Method and apparatus for handling on-demand synchronization signal block (OD-SSB) transmission / reception

Abstract

Methods and apparatuses for handling On-Demand Synchronization Signal Block (OD-SSB) transmissions / receptions are provided. The method includes receiving one or more Radio Resource Control (RRC) configurations indicating at least one of at least one OD-SSB configuration identifier, at least one duration, at least one SSB index, or at least one periodicity; receiving a Medium Access Control (MAC) Control Element (CE) including at least one field and at least one indication; in response to determining that a first field of the at least one field is set to a first value, determining that a Synchronization Signal Block (SSB) transmission from a first cell corresponding to the first field is activated, and receiving an SSB from the first cell based on an SSB pattern corresponding to the first cell; and in response to determining that the first field is set to a second value, determining that the SSB transmission is deactivated.

Description

METHOD AND APPARATUS FOR HANDLING ON-DEMAND SYNCHRONIZATION SIGNAL BLOCK (OD-SSB) TRANSMISSION / RECEPTION

[0001] The present disclosure is related to wireless communication and, more specifically, to methods and apparatuses for handling On-Demand Synchronization Signal Block (OD-SSB) transmissions / receptions.

[0002] The present disclosure claims the benefit of and priority to U.S. Provisional Patent Application Serial No. 63 / 559,215, filed on February 29, 2024, entitled “On-demand SSB triggering,” the content of which is hereby incorporated herein fully by reference into the present application for all purposes.

[0003] Various efforts have been made to improve different aspects of wireless communication for the cellular wireless communication systems, such as the 5thGeneration (5G) New Radio (NR) system, by improving data rate, latency, reliability, and mobility. The 5G NR system is designed to provide flexibility and configurability to optimize network services and types, accommodating various use cases, such as enhanced Mobile Broadband (eMBB), massive Machine-Type Communication (mMTC), and Ultra-Reliable and Low-Latency Communication (URLLC). As the demand for radio access continues to increase, however, there exists a need for further improvements in the art.Summery of Invention

[0004] The present disclosure is related to methods and apparatuses for handling On-Demand Synchronization Signal Block (OD-SSB) transmissions / receptions.

[0005] According to a first aspect of the present disclosure, a User Equipment (UE) for handling On-Demand-Synchronization Signal Block (OD-SSB) receptions is provided. The UE includes at least one processor and at least one non-transitory computer-readable medium coupled to the at least one processor and storing one or more computer-executable instructions that, when executed by the at least one processor, cause the UE to receive one or more Radio Resource Control (RRC) configurations indicating at least one of at least one OD-SSB configuration identifier, at least one duration, at least one SSB index, or at least one periodicity; receive a Medium Access Control (MAC) Control Element (CE) including at least one field and at least one indication that indicates at least one of a subset of the at least one OD-SSB configuration identifier, a subset of the at least one duration, a subset of the at least one SSB index, or a subset of the at least one periodicity; in response to determining that a first field of the at least one field is set to a first value, determine that a Synchronization Signal Block (SSB) transmission from a first cell corresponding to the first field is activated, and receive an SSB from the first cell based on an SSB pattern corresponding to the first cell, where the SSB pattern is determined based on the RRC configuration and the MAC CE; and in response to determining that the first field is set to a second value, determine that the SSB transmission from the first cell is deactivated.

[0006] In some implementations of the first aspect of the present disclosure, the one or more computer-executable instructions, when executed by the at least one processor, further cause the UE to: in response to determining that the SSB transmission from the first cell corresponding to the first field is activated, perform a Radio Resource Management (RRM) measurement on the first cell; and in response to determining that the SSB transmission from the first cell is deactivated, forgo performing the RRM measurement on the first cell.

[0007] In some implementations of the first aspect of the present disclosure, the at least one field includes multiple fields including the first field, and each field of the multiple fields corresponds to a respective cell.

[0008] In some implementations of the first aspect of the present disclosure, among cells corresponding to the multiple fields, a first portion of the cells supports an OD-SSB operation and a second portion of the cells does not support the OD-SSB operation.

[0009] In some implementations of the first aspect of the present disclosure, all cells corresponding to the multiple fields are Secondary Cells (SCells).

[0010] In some implementations of the first aspect of the present disclosure, all cells corresponding to the multiple fields support an OD-SSB operation.

[0011] In some implementations of the first aspect of the present disclosure, the one or more computer-executable instructions, when executed by the at least one processor, further cause the UE to determine the SSB pattern based on the RRC configuration and the at least one indication of the MAC CE in response to receiving the MAC CE.

[0012] In some implementations of the first aspect of the present disclosure, each field of the at least one field is a 1-bit indicator.

[0013] According to a second aspect of the present disclosure, a method of a User Equipment (UE) for handling On-Demand-Synchronization Signal Block (OD-SSB) receptions is provided. The method includes receiving one or more Radio Resource Control (RRC) configurations indicating at least one of at least one OD-SSB configuration identifier, at least one duration, at least one SSB index, or at least one periodicity; receiving a Medium Access Control (MAC) Control Element (CE) including at least one field and at least one indication that indicates at least one of a subset of the at least one OD-SSB configuration identifier, a subset of the at least one duration, a subset of the at least one SSB index, or a subset of the at least one periodicity; in response to determining that a first field of the at least one field is set to a first value, determining that a Synchronization Signal Block (SSB) transmission from a first cell corresponding to the first field is activated, and receiving an SSB from the first cell based on an SSB pattern corresponding to the first cell, where the SSB pattern is determined based on the RRC configuration and the MAC CE; and in response to determining that the first field is set to a second value, determining that the SSB transmission from the first cell is deactivated.

[0014] According to a third aspect of the present disclosure, a Base Station (BS) is provided. The BS includes at least one processor and at least one non-transitory computer-readable medium coupled to the at least one processor and storing one or more computer-executable instructions that, when executed by the at least one processor, cause the BS to transmit, to a User Equipment (UE), one or more Radio Resource Control (RRC) configurations indicating at least one of at least one OD-SSB configuration identifier, at least one duration, at least one SSB index, or at least one periodicity; transmit, to the UE, a Medium Access Control (MAC) Control Element (CE) including at least one field and at least one indication that indicates at least one of a subset of the at least one OD-SSB configuration identifier, a subset of the at least one duration, a subset of the at least one SSB index, or a subset of the at least one periodicity; in response to setting a first field of the at least one field to a first value, activate a Synchronization Signal Block (SSB) transmission by transmitting, based on an SSB pattern determined based on the RRC configuration and the MAC CE, at least one OD-SSB to the UE via a first cell corresponding to the first field for a Radio Resource Management (RRM) measurement; and in response to setting the first field to a second value, deactivate the SSB transmission by forgoing transmitting any OD-SSB to the UE via the first cell.

[0015] In some implementations of the third aspect of the present disclosure, the at least one field includes multiple fields including the first field, and each field of the multiple fields corresponds to a respective cell.

[0016] In some implementations of the third aspect of the present disclosure, among cells corresponding to the multiple fields, a first portion of the cells supports an OD-SSB operation and a second portion of the cells does not support the OD-SSB operation.

[0017] In some implementations of the third aspect of the present disclosure, the second portion of the cells includes a second cell corresponding to a second field of the multiple fields, and the one or more computer-executable instructions, when executed by the at least one processor, further cause the BS to set the second field to the first value; and transmit an SSB to the UE via the second cell.

[0018] In some implementations of the third aspect of the present disclosure, all cells corresponding to the multiple fields are Secondary Cells (SCells).

[0019] In some implementations of the third aspect of the present disclosure, all cells corresponding to the multiple fields support an OD-SSB operation.

[0020] Aspects of the present disclosure are best understood from the following detailed disclosure when read with the accompanying drawings. Various features are not drawn to scale. Dimensions of various features may be arbitrarily increased or reduced for clarity of discussion.

[0021] FIG. 1 is a flowchart illustrating method / process for handling OD-SSB receptions, according to an example implementation of the present disclosure.

[0022] FIG. 2 is a flowchart illustrating method / process for handling OD-SSB transmissions, according to an example implementation of the present disclosure.

[0023] FIG. 3 is a block diagram illustrating node for wireless communications, in accordance with various aspects of the present disclosure.

[0024] Some of the abbreviations in the present application are defined as follows and, unless otherwise specified, the abbreviations have the following meanings: Abbreviation　　　　　　　　Full name 3GPP　　　　　　　　3rd Generation Partnership Project 5G　　　　　　　　　　　　5th Generation 5GC　　　　　　　　　　　　5G Core ACK　　　　　　　　Acknowledgement AN-PDB　　　　　　　　Access Network Packet Delay Budget ARFCN　　　　　　　　Absolute Radio Frequency Channel Number AS　　　　　　　　　　　　Access Stratum ASN.1　　　　　　　　Abstract Syntax Notation One BFRQ　　　　　　　　Beam Failure Recovery Request BS　　　　　　　　　　　　Base Station BSR　　　　　　　　　　　　Buffer Status Report BWP　　　　　　　　Bandwidth Part C-RNTI　　　　　　　　Cell Radio Network Temporary Identifier CA　　　　　　　　　　　　Carrier Aggregation CAG　　　　　　　　Closed Access Group CB　　　　　　　　　　　　Codebook-Based CG　　　　　　　　　　　　Configured Grant CIF　　　　　　　　　　　　Carrier Indicator Field CJT　　　　　　　　　　　　Coherent Joint Transmission CN　　　　　　　　　　　　Core Network CN-PDB　　　　　　　　Core Network Packet Delay Budget CORESET　　　　Control Resource Set CPE　　　　　　　　　　　　Customer Premises Equipment CQI　　　　　　　　　　　　Channel Quality Indication CRC　　　　　　　　Cyclic Redundancy Check CSI　　　　　　　　　　　　Channel State Information CSI-RS　　　　　　　　Channel State Information Reference Signal CS-RNTI　　　　　　　　Configured Scheduling Radio Network Temporary Identifier CSS　　　　　　　　　　　　Common Search Space CU　　　　　　　　　　　　Central Unit DAPS　　　　　　　　Dual Active Protocol Stack DC　　　　　　　　　　　　Dual Connectivity DCI　　　　　　　　　　　　Downlink Control Information DG　　　　　　　　　　　　Dynamic Grant DI　　　　　　　　　　　　Delay Information DL　　　　　　　　　　　　Downlink DL-SCH　　　　　　　　Downlink Shared Channel DMRS　　　　　　　　Demodulation Reference Signal DR　　　　　　　　　　　　Delay Report DRB　　　　　　　　Data Radio Bearer DTCH　　　　　　　　Dedicated Traffic Channel DU　　　　　　　　　　　　Distributed Unit ETSI　　　　　　　　European Telecommunications Standards Institute E-UTRA　　　　　　　　Evolved Universal Terrestrial Radio Access EN-DC　　　　　　　　E-UTRA NR Dual Connectivity EPC　　　　　　　　　　　　Evolved Packet Core eMBB　　　　　　　　Enhanced Mobile BroadBand eMTC　　　　　　　　Enhanced Machine Type Communication eNB　　　　　　　　　　　　Evolved Node B FDD　　　　　　　　Frequency Division Duplexing FDRA　　　　　　　　Frequency Domain Resource Allocation FR　　　　　　　　　　　　Frequency Range FR1　　　　　　　　　　　　Frequency Range 1 FR2　　　　　　　　　　　　Frequency Range 2 FWA　　　　　　　　Fixed Wireless Access GEO　　　　　　　　Geostationary Equatorial Orbit gNB　　　　　　　　　　　　Next Generation Node B GNSS　　　　　　　　Global Navigation Satellite System GPS　　　　　　　　　　　　Global Positioning System GW　　　　　　　　　　　　Gateway HARQ　　　　　　　　Hybrid Automatic Repeat Request HO　　　　　　　　　　　　Handover FR　　　　　　　　　　　　Frequency Range IAB　　　　　　　　　　　　Integrated Access and Backhaul ID　　　　　　　　　　　　Identity IE　　　　　　　　　　　　Information Element IoT　　　　　　　　　　　　Internet of Things ITS　　　　　　　　　　　　Intelligent Transportation System ITU　　　　　　　　　　　　International Telecommunication Union L1　　　　　　　　　　　　Layer 1 L2　　　　　　　　　　　　Layer 2 L3　　　　　　　　　　　　Layer 3 LAN　　　　　　　　Local Area Network LCH　　　　　　　　Logical Channel LCID　　　　　　　　Logical Channel Identity LEO　　　　　　　　　　　　Low Earth Orbit LTE 　　　　　　　　Long Term Evolution LSB　　　　　　　　　　　　Least Significant Bit MAC　　　　　　　　Medium Access Control MAC CE　　　　　　　　MAC Control Element MCG　　　　　　　　Master Cell Group MCS　　　　　　　　Modulation and Coding Scheme MEO　　　　　　　　Medium Earth Orbit MIB　　　　　　　　　　　　Master Information Block MIMO　　　　　　　　Multi-Input Multi-Output mMTC　　　　　　　　Massive Machine Type Communications MN　　　　　　　　　　　　Master Node MTC　　　　　　　　Machine Type Communication NACK　　　　　　　　Negative Acknowledgement NAS　　　　　　　　Non-Access Stratum NB-IoT　　　　　　　　Narrow Band Internet of Things NCB　　　　　　　　Non-Codebook-Based NDI　　　　　　　　　　　　New Data Indicator NES　　　　　　　　　　　　Network Energy Saving NPN　　　　　　　　Non-Public Network NR　　　　　　　　　　　　New Radio NR-U　　　　　　　　NR Unlicensed NTN　　　　　　　　Non-Terrestrial Network OD-SSB　　　　　　　　On-Demand Synchronization Signal Block PA　　　　　　　　　　　　Power Amplifier PBCH　　　　　　　　Physical Broadcast Channel PCell　　　　　　　　Primary Cell PCI　　　　　　　　　　　　Physical Cell Identity PDB　　　　　　　　　　　　Packet Delay Budget PDCCH　　　　　　　　Physical Downlink Control Channel PDCP　　　　　　　　Packet Data Convergence Protocol PDSCH　　　　　　　　Physical Downlink Shared Channel PDU　　　　　　　　Protocol Data Unit PHY　　　　　　　　Physical PLMN 　　　　　　　　Public Land Mobile Network PMI　　　　　　　　　　　　Precoding Matrix indicator PNI-NPN　　　　　　　　Public Network Integrated Non-Public Network PRACH　　　　　　　　Physical Random Access Channel PSDB　　　　　　　　PDU Set Delay Budget PUCCH　　　　　　　　Physical Uplink Control Channel PUSCH　　　　　　　　Physical Uplink Shared Channel QCL　　　　　　　　Quasi-CoLocation QoS　　　　　　　　　　　　Quality of Service RA　　　　　　　　　　　　Random Access RACH　　　　　　　　Random Access Channel RAN　　　　　　　　Radio Access Network RAR　　　　　　　　Random Access Response RAT　　　　　　　　　　　　Radio Access Technology RE　　　　　　　　　　　　Resource Element Rel-15　　　　　　　　Release 15 Rel-16　　　　　　　　Release 16 Rel-17 　　　　　　　　Release 17 Rel-18　　　　　　　　Release 18 RF　　　　　　　　　　　　Radio Frequency RLC　　　　　　　　　　　　Radio Link Control RS　　　　　　　　　　　　Reference Signal RLF　　　　　　　　　　　　Radio Link Failure RSTD　　　　　　　　Reference Signal Time Difference Measurement RNTI　　　　　　　　Radio Network Temporary Identifier RO　　　　　　　　　　　　RACH Occasion RRC　　　　　　　　Radio Resource Control RRM　　　　　　　　Radio Resource Management RS　　　　　　　　　　　　Reference Signal RSRP　　　　　　　　Reference Signal Received Power RSRQ　　　　　　　　Reference Signal Receiving Quality RV　　　　　　　　　　　　Redundancy Version RX　　　　　　　　　　　　Reception SCell　　　　　　　　Secondary Cell SCG　　　　　　　　　　　　Secondary Cell Group SDT　　　　　　　　　　　　Small Data Transmission SI　　　　　　　　　　　　System Information SIB　　　　　　　　　　　　System Information Block SL　　　　　　　　　　　　Sidelink SLIV　　　　　　　　Start and Length Indicator Value SN　　　　　　　　　　　　Secondary Node SNPN　　　　　　　　Stand-alone Non-Public Network SpCell　　　　　　　　Special Cell SR　　　　　　　　　　　　Scheduling Request SRB　　　　　　　　　　　　Signaling Radio Bearer SRS　　　　　　　　　　　　Sounding Reference Signal SRI　　　　　　　　　　　　SRS Resource Indicator SSB　　　　　　　　　　　　Synchronization Signal Block SSS　　　　　　　　　　　　Secondary Synchronization Signal SUL　　　　　　　　　　　　Supplementary Uplink TA　　　　　　　　　　　　Timing Advance TAG　　　　　　　　　　　　Timing Advance Group TAT 　　　　　　　　Time Alignment Timer TAU　　　　　　　　　　　　Tracking Area Update TB　　　　　　　　　　　　Transport Block TCI　　　　　　　　　　　　Transmission Configuration Indication TDD　　　　　　　　Time Division Duplexing TDRA　　　　　　　　Time Domain Resource Allocation TN　　　　　　　　　　　　Terrestrial Network TPC　　　　　　　　　　　　Transmission Power Control TPMI　　　　　　　　Transmit Precoder Matrix Indication TRP　　　　　　　　　　　　Transmission Reception Point TRS 　　　　　　　　Tracking Reference Signal TRX　　　　　　　　Transmission / Reception TS　　　　　　　　　　　　Technical Specification TX　　　　　　　　　　　　Transmission UCI　　　　　　　　　　　　Uplink Control Information UE　　　　　　　　　　　　User Equipment UL　　　　　　　　　　　　Uplink UL-CG　　　　　　　　Uplink-Configured Grant UPF　　　　　　　　　　　　User Plane Function URLLC　　　　　　　　Ultra-Reliable and Low-Latency Communications USIM　　　　　　　　Universal Subscriber Identity Module USS 　　　　　　　　UE-specific Search Space UTC　　　　　　　　Coordinated Universal Time V2X　　　　　　　　　　　　Vehicle-to-Everything VSAT　　　　　　　　Very Small Aperture Terminal XR　　　　　　　　　　　　Extended Reality

[0025] The following contains specific information related to implementations of the present disclosure. The drawings and their accompanying detailed disclosure are merely directed to implementations. However, the present disclosure is not limited to these implementations. Other variations and implementations of the present disclosure will be obvious to those skilled in the art.

[0026] Unless noted otherwise, like or corresponding elements among the drawings may be indicated by like or corresponding reference numerals. Moreover, the drawings and illustrations in the present disclosure are generally not to scale and are not intended to correspond to actual relative dimensions.

[0027] For consistency and ease of understanding, like features may be identified (although, in some examples, not illustrated) by the same numerals in the drawings. However, the features in different implementations may be different in other respects and shall not be narrowly confined to what is illustrated in the drawings.

[0028] References to “one implementation,” “an implementation,” “example implementation,” “various implementations,” “some implementations,” “implementations of the present application,” etc., may indicate that the implementation(s) of the present application so described may include a particular feature, structure, or characteristic, but not every possible implementation of the present application necessarily includes the particular feature, structure, or characteristic. Further, repeated use of the phrase “in one implementation,” or “in an example implementation,” “an implementation,” do not necessarily refer to the same implementation, although they may. Moreover, any use of phrases like “implementations” in connection with “the present application” are never meant to characterize that all implementations of the present application must include the particular feature, structure, or characteristic, and should instead be understood to mean “at least some implementations of the present application” includes the stated particular feature, structure, or characteristic.

[0029] The term “coupled” is defined as connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The term “comprising,” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series, and the equivalent.

[0030] The expression “at least one of A, B and C” or “at least one of the following: A, B and C” means “only A, or only B, or only C, or any combination of A, B and C.” The terms “system” and “network” may be used interchangeably. The term “and / or” is only an association relationship for describing associated objects and represents that three relationships may exist such that A and / or B may indicate that A exists alone, A and B exist at the same time, or B exists alone. The character “ / ” generally represents that the associated objects are in an “or” relationship.

[0031] For the purposes of explanation and non-limitation, specific details, such as functional entities, techniques, protocols, and standards, are set forth for providing an understanding of the disclosed technology. In other examples, detailed disclosure of well-known methods, technologies, systems, and architectures are omitted so as not to obscure the present disclosure with unnecessary details.

[0032] Persons skilled in the art will immediately recognize that any network function(s) or algorithm(s) disclosed may be implemented by hardware, software, or a combination of software and hardware. Disclosed functions may correspond to modules which may be software, hardware, firmware, or any combination thereof.

[0033] A software implementation may include computer executable instructions stored on a computer-readable medium, such as memory or other type of storage devices. One or more microprocessors or general-purpose computers with communication processing capability may be programmed with corresponding executable instructions and perform the disclosed network function(s) or algorithm(s).

[0034] The microprocessors or general-purpose computers may include Application-Specific Integrated Circuits (ASICs), programmable logic arrays, and / or one or more Digital Signal Processor (DSPs). Although some of the disclosed implementations are oriented to software installed and executing on computer hardware, alternative implementations implemented as firmware, as hardware, or as a combination of hardware and software are well within the scope of the present disclosure. The computer-readable medium includes but is not limited to Random Access Memory (RAM), Read Only Memory (ROM), Erasable Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), flash memory, Compact Disc Read-Only Memory (CD-ROM), magnetic cassettes, magnetic tape, magnetic disk storage, or any other equivalent medium capable of storing computer-readable instructions.

[0035] A radio communication network architecture such as a Long-Term Evolution (LTE) system, an LTE-Advanced (LTE-A) system, an LTE-Advanced Pro system, or a 5G NR Radio Access Network (RAN) typically includes at least one base station (BS), at least one UE, and one or more optional network elements that provide connection within a network. The UE communicates with the network such as a Core Network (CN), an Evolved Packet Core (EPC) network, an Evolved Universal Terrestrial RAN (E-UTRAN), a 5G Core (5GC), or an internet via a RAN established by one or more BSs.

[0036] A UE may include, but is not limited to, a mobile station, a mobile terminal or device, or a user communication radio terminal. The UE may be a portable radio equipment that includes, but is not limited to, a mobile phone, a tablet, a wearable device, a sensor, a vehicle, or a Personal Digital Assistant (PDA) with wireless communication capability. The UE is configured to receive and transmit signals over an air interface to one or more cells in a RAN.

[0037] The BS may be configured to provide communication services according to at least a Radio Access Technology (RAT) such as Worldwide Interoperability for Microwave Access (WiMAX), Global System for Mobile communications (GSM) that is often referred to as 2G, GSM Enhanced Data rates for GSM Evolution (EDGE) RAN (GERAN), General Packet Radio Service (GPRS), Universal Mobile Telecommunication System (UMTS) that is often referred to as 3G based on basic wideband-code division multiple access (W-CDMA), high-speed packet access (HSPA), LTE, LTE-A, evolved LTE (eLTE) that is LTE connected to 5GC, NR (often referred to as 5G), and / or LTE-A Pro. However, the scope of the present disclosure is not limited to these protocols.

[0038] The BS may include, but is not limited to, a node B (NB) in the UMTS, an evolved node B (eNB) in LTE or LTE-A, a radio network controller (RNC) in UMTS, a BS controller (BSC) in the GSM / GERAN, an ng-eNB in an Evolved Universal Terrestrial Radio Access (E-UTRA) BS in connection with 5GC, a next generation Node B (gNB) in the 5G-RAN, or any other apparatus capable of controlling radio communication and managing radio resources within a cell. The BS may serve one or more UEs via a radio interface.

[0039] The BS may be operable to provide radio coverage to a specific geographical area using multiple cells forming the RAN. The BS may support the operations of the cells. Each cell may be operable to provide services to at least one UE within its radio coverage.

[0040] Each cell (often referred to as a serving cell) may provide services to serve one or more UEs within its radio coverage, such that each cell schedules the DL (and optionally UL resources) to at least one UE within its radio coverage for DL (and optionally UL packet transmissions from the UE). The BS may communicate with one or more UEs in the radio communication system via the plurality of cells.

[0041] A cell may allocate sidelink (SL) resources for supporting the Proximity Service (ProSe) or Vehicle to Everything (V2X) service. Each cell may have overlapped coverage areas with other cells.

[0042] In Multi-RAT Dual Connectivity (MR-DC) cases, the primary cell of a Master Cell Group (MCG) or a Secondary Cell Group (SCG) may be referred to as a Special Cell (SpCell). A Primary Cell (PCell) may include the SpCell of an MCG. A Primary SCG Cell (PSCell) may include the SpCell of an SCG. MCG may include a group of serving cells associated with the Master Node (MN), including the SpCell and optionally one or more Secondary Cells (SCells). An SCG may include a group of serving cells associated with the Secondary Node (SN), including the SpCell and optionally one or more SCells.

[0043] As described above, the frame structure for NR supports flexible configurations for accommodating various next generation (e.g., 5G) communication requirements, such as Enhanced Mobile Broadband (eMBB), Massive Machine Type Communication (mMTC), and Ultra-Reliable and Low-Latency Communication (URLLC), while fulfilling high reliability, high data rate, and low latency requirements. The Orthogonal Frequency-Division Multiplexing (OFDM) technology in the 3GPP may serve as a baseline for an NR waveform. The scalable OFDM numerology, such as adaptive sub-carrier spacing, channel bandwidth, and Cyclic Prefix (CP), may also be used.

[0044] Two coding schemes may be considered for NR, specifically Low-Density Parity-Check (LDPC) code and Polar Code. The coding scheme adaption may be configured based on channel conditions and / or service applications.

[0045] At least the DL transmission data, a guard period, and UL transmission data should be included in a transmission time interval (TTI) of a single NR frame. The respective portions of the DL transmission data, the guard period, and the UL transmission data should also be configurable based on, for example, the network dynamics of NR. SL resources may also be provided in an NR frame to support ProSe services or V2X services.

[0046] Any two or more of the following paragraphs, (sub)-bullets, points, actions, behaviors, terms, or claims described in the present disclosure may be combined logically, reasonably, and properly to form a specific method.

[0047] Any sentence, paragraph, (sub)-bullet, point, action, behaviors, terms, or claims described in the present disclosure may be implemented independently and separately to form a specific method.

[0048] Dependency, e.g., “based on”, “more specifically”, “preferably”, “in one embodiment”, “in some implementations”, etc., in the present disclosure is just one possible example which would not restrict the specific method.

[0049] “A and / or B” in the present disclosure may refer to either A or B, both A and B, or at least one of A and B.

[0050] In this disclosure, “X / Y” may encompass the meanings of “X or Y,” “X and Y,” and “X and / or Y,” as indicated by two or more of the sentences, paragraphs, sub-bullets, points, actions, behaviors, terms, alternatives, aspects, examples, embodiments, or claims described in the following invention(s).

[0051] One aspect of the present disclosure may be applied in various contexts, including communications, communication equipment (such as mobile telephone apparatus, base station apparatus, wireless LAN apparatus, and / or sensor devices), integrated circuits (such as communication chips), and software programs, among others.

[0052] The terms “an antenna port” and “antenna ports,” as discussed in the present disclosure, may refer to “an antenna port used for transmission of PUSCH(s) / PUCCH(s)” and “antenna ports used for transmission of PUSCH(s) / PUCCH(s),” respectively.

[0053] Some of the terms, definitions, and / or abbreviations included in the present disclosure may either be sourced from existing documents (such as those from ETSI, ITU, or other sources) or may be newly created by experts from the 3GPP whenever there was a need for a precise vocabulary.

[0054] Examples of some selected terms in the present disclosure are provided as follows.

[0055] Antenna Panel: A conceptual term for a UE antenna implementation. It may be assumed that a panel may be an operational unit for controlling a transmit spatial filter (beam). A panel may typically include multiple antenna elements. In some implementations, a beam may be formed by a panel, and in order to form two beams simultaneously, two panels may be needed. Such simultaneous beamforming by multiple panels may be subject to the UE capability. A similar definition for “panel” may be applicable by applying spatial receiving filtering characteristics.

[0056] Beam: A beam may include a spatial (domain) filtering. In one example, the spatial filtering may be applied in the analog domain by adjusting a phase and / or amplitude of the signal before being transmitted by a corresponding antenna element. In another example, the spatial filtering may be applied in the digital domain by the Multi-Input Multi-Output (MIMO) technique in the wireless communication system. For example, “a UE made a PUSCH transmission by using a specific beam” may mean that the UE made the PUSCH transmission by using the specific spatial / digital domain filter. The “beam” may also be, but is not limited to be, represented as an antenna, an antenna port, an antenna element, a group of antennas, a group of antenna ports, or a group of antenna elements. The beam may also be formed by a certain reference signal resource. In short, the beam may be equivalent to a spatial domain filter through which the EM wave is radiated. Beam information may include details about the selected or utilized beam or spatial filter. In some implementations, the individual beams (e.g., spatial filters) may be used to transmit individual reference signals. Consequently, a beam or beam information may be represented by one or more reference signal resource indices.

[0057] DCI: DCI may include downlink control information, and there may be various DCI formats used in a PDCCH. The DCI format may be a predefined format in which the downlink control information may be packed / formed and transmitted in a PDCCH.

[0058] TCI state: a TCI state may include parameters for configuring a QCL relationship between one or more DL reference signals and a target reference signal set. For example, a target reference signal set may be the DMRS ports of a PDSCH or a PDCCH.

[0059] HARQ: A functionality that ensures the delivery between peer entities at Layer 1 (e.g., Physical Layer). A single HARQ process may support one Transport Block (TB) when the physical layer is not configured for the downlink / uplink spatial multiplexing, and when the physical layer is configured for downlink / uplink spatial multiplexing, a single HARQ process may support one or more TBs. There may be one HARQ entity per serving cell. Each HARQ entity may support a parallel (number of) DL and UL HARQ process.

[0060] In the present disclosure, although the term “gNB” may have been used throughout the document, it should be understood that the term “gNB” may be replaced by any other type of BS (e.g., an eNB). Additionally, unless specifically noted otherwise, the terms “SSB” and “OD-SSB” may be used interchangeably in the present disclosure.

[0061] Network Energy Saving (NES) technology may be considered of great importance for environmental sustainability, for reducing the environmental impact through greenhouse gas emissions reduction, and for achieving operational cost savings. As the 5G technology may become pervasive across industries and geographical areas, and the handling of more advanced services and applications may require very high data rates, such as Extended Reality (XR), the networks may become denser and may use more antennas, larger bandwidths, and more frequency bands. The environmental impact of the 5G technology may need to stay under control, and novel solutions to improve the network energy savings may need to be developed.

[0062] The 3GPP Rel-18 work on NES for New Radio (NR) technology may have led to the specification of beneficial techniques, primarily for the Radio Resource Control (RRC) Connected mode, the user-specific signals and channels, and the low load scenarios. The techniques specified in Release-18 may include the SSB-less Secondary Cell (SCell) operation for inter-band Carrier Aggregation (CA) for Frequency Range 1 (FR1) and co-located cells, the enhancement on the cell DTX / DRX mechanism including the alignment of the cell DTX / DRX operations and the UE DRX operations in the RRC_CONNECTED mode, the inter-node information exchange on the cell DTX / DRX operations, the techniques in the spatial and power domains to enable efficient adaptation of spatial elements as well as efficient adaptation of power offset values between the Physical Downlink Shared Channel (PDSCH) and the Channel State Information-Reference Signal (CSI-RS), the mechanisms to prevent legacy UEs from camping on cells adopting the Rel-18 NES techniques, the Conditional Handover (CHO) procedure enhancement(s), and the inter-node beam activation and enhancements on restricting paging in a limited area, and the corresponding Radio Resource Management (RRM) / Radio Frequency (RF) core requirements.

[0063] In the upcoming Release-19 work, one of the objectives may be to specify procedures and signaling method(s) to support On-Demand SSB (OD-SSB) SCell operations for UEs in the RRC_CONNECTED mode configured with CA, for both intra- / inter-band CA. More specifically, the triggering method(s) may be for further study, including selection from the UE uplink wake-up-signal using an existing signal / channel, the cell on / off indication via backhaul, and the SCell activation / deactivation signaling.

[0064] In general, upon a successful reception of the PDSCH carrying an SCell activation MAC CE, a UE may send a Hybrid Automatic Repeat Request (HARQ) feedback to the network. Subsequently, the UE may obtain time and frequency synchronization based on the reference signal (e.g., the SSB) from the target SCell (e.g., the SCell(s) activated by the SCell activation MAC CE). The UE may then perform CSI-RS measurements and CQI and / or CSI reporting, after which the UE may be scheduled for reception / transmission at the SCell. For a configured SSB-less SCell, the network may send an SCell activation MAC CE to activate the SSB-less SCell. However, since there is no SSB transmitted in the corresponding SSB-less SCell, such absence may lead to the failure of SCell activation. For example, the time / frequency synchronization may not be completed and the UE may not perform subsequent measurements for supporting the data transmission. Therefore, a triggering mechanism of enabling / activating an SSB-less SCell to perform SSB transmissions while a gNB sends an SCell activation MAC CE may be required. Additionally, the gNB may request the UE to measure a deactivated SCell or a neighboring cell, and there may be a need to trigger the relative SSB transmission from the deactivated SCell or the neighboring cell for the purpose. Therefore, a triggering mechanism may be needed in addition to the SCell activation. For example, after the initial access, or upon the handover / RRC connection reestablishment in consequence of UE mobility, the gNB may trigger the transmission of OD-SSB on candidate SCell(s) via a PCell.

[0065] The present disclosure provides several approaches for implementing an OD-SSB triggering mechanism. A first approach may include utilizing DCI containing the CIF(s) to indicate the SSB transmission (e.g., to indicate the UE that one or more corresponding SSB-less cells are activated to perform the SSB transmission) in case the corresponding SCell is deactivated. A second approach may include using a MAC CE to indicate the SSB transmission (e.g., to indicate the UE that one or more corresponding SSB-less cells are activated to perform the SSB transmission, along with an additional IE that indicates whether the corresponding SCell is activated. A third approach may include using the DCI format 2_9 to indicate the SSB transmission (e.g., to indicate the UE that one or more corresponding SSB-less cells are activated to perform the SSB transmission in a case that the corresponding SCell is (de)activated. A fourth approach may include utilizing RRC signaling to indicate the SSB pattern and the SSB transmission (e.g., to indicate the UE the SSB pattern and to indicate the UE that one or more corresponding SSB-less cells are activated to perform the SSB transmission) in a case that the cell DTX operation is (de)activated.

[0066] The first, second, third, and fourth approaches may be implemented in combination to achieve enhanced flexibility and effectiveness in the OD-SSB triggering mechanism. These approaches may not be mutually exclusive, and the network may select and combine different approaches based on various operational scenarios and requirements.

[0067] The following descriptions provide further details regarding the first through fourth approaches for implementing the OD-SSB triggering mechanism.

[0068] First approach: using DCI with a CIF to indicate the SSB transmission in case the corresponding SCell is deactivated.

[0069] In the first approach, the DCI with a CIF may be used to indicate the SSB transmission in a case that the corresponding SCell is deactivated. The gNB may request the UE to perform measurements on an SCell regardless of whether the SCell is activated or deactivated. The SCell in the context of the present disclosure may refer to a cell that has been configured and added as an SCell within the network configuration. A normal cell may refer to a cell that may maintain continuous SSB transmissions in accordance with legacy specifications, in contrast to either an SSB-less cell or a cell that implements sparse SSB transmission patterns.

[0070] Once the gNB makes the (UE measurement) request, an SSB-less SCell, which originally does not transmit any SSB, may resume its SSB transmission in response to the request to facilitate the measurement and such operation may be triggered by the network. The measurement requirement and the SCell activation / deactivation behavior may not be coupled. That is, the requirements for UE measurement and the procedures for SCell activation / deactivation may operate independently, such that the execution of one procedure may not be contingent upon the execution of the other procedure.

[0071] In some implementations, the gNB may use the CIF in the DCI format(s) to enable cross-carrier scheduling, where a scheduling cell may provide a resource grant for a scheduled cell. An RRC (re)configuration message / IE, e.g., the CrossCarrierSchedulingConfig IE, may be applied to configure which cells may function as scheduling cells and which cells may function as scheduled cells. After receiving the RRC configuration, the UE may interpret the CIF value as a serving cell index, thereby enabling the UE to identify the resources granted to the corresponding SCell through DCI decoding. In some implementations, the CIF may typically be utilized to indicate an activated SCell.

[0072] In some implementations, with the same RRC configuration (e.g., the RRC (re)configuration message / IE, CrossCarrierSchedulingConfig), the gNB may set the corresponding CIF in the DCI for the deactivated SCell. This method may not require any new RRC message or new DCI format, thereby maintaining the DCI size and signaling overhead within the limits of the current specification. Additionally, this method may offer enhanced flexibility by enabling the gNB to utilize existing DCI fields, such as the MCS field, the NDI field, the RV field, and other fields, to indicate the SSB pattern information for OD-SSB transmission purposes. Through this method, the UE may interpret the bit patterns within the existing fields to determine the timing and location of the SSB transmission from the indicated SCell. The SSB pattern information may include parameters such as the SSB periodicity, the SSB index, and / or the duration.

[0073] After the UE receives the indication in the DCI, the UE may recognize the grant of the deactivated SCell from the gNB as an OD-SSB indication, whereby the UE may proceed to perform measurements on the associated reference signals. The other field(s) in the DCI, such as the TDRA and the FDRA fields, may be ignored by the UE since there may be no actual PDSCH / PUSCH resource grant corresponding to these fields. In some implementations, all bits in the RV field or the MCS field may be set to “1” to signify the absence of a data grant in the corresponding DCI. To enable the UE to differentiate between the DCI indicating a TCI state without data assignment and the DCI indicating an OD-SSB transmission, an existing DCI field, such as the NDI field, may be configured with a specific value (e.g., “0” or “1”) for the OD-SSB signaling. The gNB may transmit the DCI with a CIF to indicate the corresponding SCell, where the RV / MCS / FDRA field(s) may be set to a value that indicates no data assignment, while the NDI field may be set to a specific value (e.g., NDI= 0 or NDI= 1) to indicate the SSB transmission.

[0074] The gNB may resume the SSB transmission unless the gNB’s implementation prevents the resumption of the SSB transmission or the next DCI with the same CIF value (for the corresponding SCell) indicates the termination of the SSB transmission. In some implementations, the SSB transmission pattern may conform to the patterns specified in legacy specifications.

[0075] In some implementations, the gNB may use the MCS field, the NDI field, the RV field and / or other existing DCI fields to indicate the applied SSB pattern for OD-SBB transmission purposes. The UE may interpret the received bits within these fields and thus the UE may know where and when the UE may receive the SSB transmission from the indicated SCell. The SSB pattern may include the information to indicate at least one of the SSB periodicity, the SSB index, or the duration.

[0076] In some implementations, with a separate RRC configuration different from the RRC (re)configuration message / IE (e.g., the CrossCarrierSchedulingConfig IE), the gNB may use a respective CIF for the deactivated SCell. The gNB may use a new RRC message or a new RRC configuration / IE to configure an index for respective SSB-less SCells with at least one corresponding SSB pattern. Several patterns may be configured for the SCells and may be identified by separate pattern IDs.

[0077] When the UE receives DCI with a CIF (or CIF indication), the UE may further check existing resource allocation and retransmission-relating fields such as the FDRA field, and / or the HARQ process number field, and / or the Redundancy version field. Once the value is set to be all “0” or all “1” for Type 0 or Type 1 or dynamic switch, the UE may recognize that the associating CIF may refer to the SSB-less SCell configuration. The UE may interpret the CIF value based on the RRC configuration and the IE such as the index for the respective SSB-less SCells with corresponding SSB transmission pattern. In some implementations, all bits in the RV field or the MCS field may be set to “1” to represent that there is no data grant for the corresponding DCI. To let the UE distinguish from the DCI indicating the TCI state without data assignment, the existing DCI field, such as the NDI field, may be set to a specific value (e.g., “0” or “1”) for the OD-SSB signaling. The gNB may send the DCI with the CIF to indicate the corresponding SCell and may set no data assignment relative setting in the RV / MCS / FDRA field but may set the existing DCI field to the specific value to indicate the transmission of the SSB. For example, the gNB may transmit DCI that may contain two distinct types of information: the CIF may identify the target SCell, while the specific configuration of other DCI fields may indicate that this DCI may be interpreted as an SSB transmission trigger rather than a conventional data assignment. The RV field, MCS field, and FDRA field may be set to indicate no data assignment by containing predetermined values, such as all zeros or all ones, thereby signaling to the UE that this DCI may not carry conventional resource allocation information. Simultaneously, another existing DCI field, such as the NDI field, may be configured with a specific value to explicitly indicate that this DCI may serve as an SSB transmission trigger.

[0078] After sending the DCI, the gNB may resume the SSB transmission unless the gNB’s implementation prevents the resumption of the SSB transmission or the next DCI with the same CIF value (for the corresponding SSB-less SCell) indicates the termination of the SSB transmission. The resumption of the SSB transmission may follow the configured SSB pattern upon the configuration. If multiple SSB patterns are configured, the UE may re-interpret other DCI fields to acquire the indicated SSB pattern ID.

[0079] One or more SSB patterns may be used to indicate that an SIB1 is to be transmitted together with an SSB. The gNB may resume the SSB and SIB1 transmission after sending the DCI. The termination of the SSB and SIB1 transmission may be executed together with another DCI signaling.

[0080] In some implementations, with a separate RRC configuration different from the RRC (re)configuration message / IE (e.g., the CrossCarrierSchedulingConfig IE), the gNB may use a specific DCI format for the SCell. The gNB may use a new RRC message or a new RRC configuration / IE to configure an index and at least one SSB pattern for respective ones of the SSB-less SCells.

[0081] A new DCI format (e.g., an NES-specific / dedicated DCI format) with a CRC scrambled by a common RNTI (e.g., an SI-RNTI), a group-common RNTI (e.g., a G-RNTI), or a C-RNTI may be used to indicate the trigger of the OD-SSB transmission. Multiple CIFs corresponding to multiple SSB patterns may be simultaneously included in the DCI to support multiple OD-SSB triggers. For example, the DCI may simultaneously carry multiple CIFs, and each CIF may correspond to a specific SSB pattern, thereby enabling the DCI to trigger multiple OB-SSB transmissions.

[0082] After sending the DCI, the gNB may resume the SSB transmission unless the gNB’s implementation prevents the resumption of the SSB transmission or the next DCI with the same CIF value (for the corresponding SSB-less SCell) indicates the termination of the SSB transmission. One or more SSB patterns may be used to indicate that the SIB1 is to be transmitted together with the SSB. The gNB may resume the SSB and SIB1 transmission after sending the DCI. The termination of the SSB and SIB1 may be executed together with another DCI signaling.

[0083] Second approach: using a MAC CE to indicate the SSB transmission and using an additional IE to indicate whether corresponding SCell is to be activated.

[0084] In the second approach, a MAC CE may be used to indicate the SSB transmission and an additional IE to indicate whether the corresponding SCell may be activated. In some implementations, it is feasible for an NW to trigger the OD-SSB transmission when NW intends to activate the SCell. Several methods are introduced to use an activation / deactivation MAC CE to indicate the OD-SSB transmission. For example, one of the methods includes using a legacy activation MAC CE to implicitly trigger the OD-SSB transmission while activating the SCell; one of the methods includes using a new / enhanced activation MAC CE to explicitly trigger the OD-SSB transmission while activating the SCell. In some implementations, if the OD-SSB transmission can be resumed earlier than the activation, it may facilitate the process and can reduce the SCell activation delay, thus a separate signaling (other than activation MAC CE) may be designed to have two-stage activation. The activation MAC CE may be an SCell activation / deactivation MAC CE.

[0085] In the second approach, the gNB may transmit an SSB activation MAC CE to the UE to indicate that the corresponding SCells will activate the SSB transmission in a specific way. The corresponding SCells may be separately configured or jointly configured with a CA configuration. For example, the UE may be configured with a list of normal SCells and a list of SCells supporting OD-SSB operations while receiving a CA configuration or a Serving Cell configuration from the gNB. Alternatively, the UE may be configured with a list of SCells. It is possible that only the SSB-less SCell(s) may be involved in the SSB activation MAC CE, where an octet with Ci field may be used to indicate the SSB activation (while the associated Ci bit set to 1) for the SCell with SCellIndex i if the separate configuration other than SCellIndex is applied. On the other hand, all SCells may be involved in this MAC CE regardless of its SSB transmission in a case that a unified CA configuration is applied and the gNB may always set the Ci value to 1 for the normal SCell. The Ci field may be used to indicate the SSB deactivation (when the associated Ci bit is set to 0) for the SCell with an SCellIndex i.

[0086] The specific way may represent that SSB will be transmitted in a specific pattern where the pattern includes on which SSB index of the SCell, which periodicity, and which duration to accomplish the transmission. For example, a specific transmission pattern may be used to define how the SSB will be transmitted, where the pattern may include al least one of the following: (1) a specific SSB index of the SCell on which the transmission occurs, (2) a transmission periodicity, or (3) a transmission duration for accomplishing the SSB transmission. The gNB may use an existing pattern (which is the same as that of the normal SCell) or configure a separate pattern. The configuration may be achieved via an RRC message / IE or the SSB activation MAC CE.

[0087] For the second approach, at least one of the following design considerations (1) to (4) may be involved:

[0088] (1) One or more than one OD-SSB configuration ID (ODSSB_ID) field:

[0089] If the field(s) is included and / or present, the field(s) may be placed in an ascending order based on the SCellIndex for the SCells to activate its SSB transmission indicated by the Ci field(s) (e.g., the value of Ci field is set to “1”). If ODSSB_ID j is set to a non-zero value, it may indicate the corresponding OD-SSB configuration with the index ODSSB_ID j. If ODSSB_ID j is set to zero, it may indicate that no OD-SSB configuration is used for the corresponding SCell, which means that the UE may assume a legacy SSB pattern for the corresponding SCell should be transmitted.

[0090] In some implementations, this field(s) may be included and / or may be present only when at least one OD-SSB configuration is configured for the SCell with Ci set to 1.

[0091] (2) Zero, one, or more than one duration field:

[0092] If the field(s) is included and / or present, the field(s) may be placed in an ascending order based on the SCellIndex for SSB to be activated indicated by the Ci field(s).

[0093] In some implementations, this field may be included and / or may be present only when the corresponding ODSSB_ID field are included and / or present as well and set to a non-zero value. In this case, if the value indicated in the duration field is set to a non-zero value, this field (e.g., duration field) may further indicate the field value overrides the OD-SSB transmission duration configured in the configuration with the corresponding ODSSB_ID. If the value indicated in the duration field is set to a zero value, the UE may ignore this field.

[0094] (3) Zero, one, or more than one SSB index field:

[0095] If the field(s) is included and / or present, the field(s) may be placed in ascending order based on the SCellIndex for SSB to be activated indicated by the Ci field(s). The UE may measure the SSB with the an SSB index field on the SCell with the corresponding SCellIndex.

[0096] (4) Zero, one, or more than one periodicity index field:

[0097] If the field(s) is included and / or present, the field(s) may be placed in ascending order based on the SCellIndex for SSB to be activated indicated by the Ci field(s).

[0098] After receiving the SSB activation MAC CE, the UE may perform (RRM) measurement on the corresponding SCells. UE may send an acknowledgement toward the SSB activation MAC CE while (1) successfully receiving the SSB activation MAC CE, or (2) successfully finishing the measurement, or (3) both (1) and (2) being completed. The gNB may re-transmit the SSB activation MAC CE and keep the SSB transmission if there is an NACK or a failure report from the UE or if the gNB does not receive any acknowledgement from the UE within a time interval. Alternatively, the gNB may keep SSB transmission until receiving a positive acknowledgement from the UE.

[0099] The gNB may send a consequent (2nd) activation MAC CE (e.g., legacy activation MAC CE) after receiving the positive acknowledgement from the UE to activate the SSB transmission. In some implementations, the gNB may append one or more SCell activation fields to the activation MAC CE. If the field(s) is included and / or present in the activation MAC CE, the field(s) may be placed in ascending order based on the SCellIndex for the SCells to activate the SSB transmission associated with the SCells indicated by the Ci field(s). If the SCell activation field is set to a non-zero value, the UE may know the corresponding SCell should be activated after n+X slot where UE receives the SSB activation MAC CE on n slot and X may be a value based on at least one of the following factors: the SCell’s SCS, the UE’s capability, the gNB’ configuration, and a default value specified by the NW.

[0100] Otherwise, if the SCell activation field is set to a zero value, UE will assume there is no consequent activation request from gNB. gNB may not append the SCell activation field in SSB activation MAC CE and UE will assume a default behavior will be applied for the determination of SCell activation or a configured behavior will be applied. For instance, if the field is skipped in the SSB activation MAC CE, UE will not activate the corresponding SCell(s) accordingly.

[0101] Another embodiment is to use DCI signaling to activate the SSB (like the designs described in the first approach) and then use existing SCell activation MAC CE to activate the SCell afterwards. It might configure an offset in RRC configuration or indicate an offset value in DCI and that UE will assume the corresponding SCell will be activated after n+X (X here refer the same parameter defined above) slot and the SCell activation MAC CE may be skipped.

[0102] Third approach: using DCI format 2_9 to indicate the SSB transmission in case the corresponding SCell is activated / deactivated.

[0103] In the third approach, a UE configured for operation on a serving cell according to one or both of a cell DTX operation by a cell DTX configuration (e.g., the cellDTXConfig IE) and a cell DRX operation by the cellDRXConfig for the serving cell, may be additionally provided by the DCI Format 2_9 a search space set to monitor the PDCCH for receiving the DCI Format 2_9 according to a common search space or a group common search space. If the UE is configured with both cell DTX operation and cell DRX operation for the serving cell, the cell DTX / DRX indicator field includes two bits where the first bit indicates the cell DTX operation and the second bit indicates the cell DRX operation. A '0' value for a bit of the cell DTX / DRX indicator field may indicate the deactivation of the cell DTX / DRX operation and a '1' value for a bit of the cell DTX / DRX indicator field may indicate the activation of cell DTX / DRX operation. It is reasonable to consider the SSB activation together with cell DTX behavior (In Rel-18, always-transmitted SSB is assumed under cell DTX active time). Regarding the third approach, the following description will be presented through Case 1, 2, and 3 scenarios:

[0104] Case 1: the SCell is activated

[0105] The UE may be requested to perform PDCCH monitoring while the activated SCell is within the Cell DTX active time. An activated SSB-less SCell may resume its SSB transmission while the DCI format 2_9 indicates the change of the Cell DTX activation / deactivation operation. As a result, the DCI format 2_9 may be an implicit trigger for OD-SSB operations. When receiving the associated DCI format 2_9, the UE may assume that the SSB-less SCell will transmit the SSB based on a legacy (SSB) pattern (e.g., with the same periodicity) if there is no further additional configuration. The UE may then perform measurements based on the legacy pattern. If an additional configuration is applied (e.g., together with SCell serving configuration or together with Cell DTX configuration), UE will assume the SSB will be transmitted in a configured way after receiving the DCI format 2_9 for the corresponding SCells. The configuration may include at least one of the following: the periodicity of SSB, the applied SSB index, the duration of SSB transmission, or the SSB transmission pattern, where the configuration may be associated with the corresponding SCells.

[0106] The gNB may resume the SSB transmission after sending the DCI format 2_9 and may terminate the SSB transmission based on the gNB’s implementation or the configured pattern. It is also possible that the gNB may adapt the SSB transmission based on the state of the cell DTX operation. For instance, if the cell DTX operation is activated (indicated by DCI format 2_9 with an indicator set to 1), the gNB may transmit the SSB in one pattern, and the gNB may transmit the SSB in another pattern if the cell DTX operation is deactivated (indicated by DCI format 2_9 with an indicator set to 0). Similarly, the different SSB patterns applied for the respective Cell DTX states may be configured or by a default setting.

[0107] Case 2: the SCell is deactivated

[0108] The UE may be required to perform SSB measurements while the deactivated SCell is within the Cell DTX active time or the Cell DTX inactive time (based on the Rel-18 specification, the SCell should keep performing SSB transmissions regardless of the Cell DTX state). It implies a deactivated SSB-less SCell should resume its SSB while the DCI format 2_9 indicates the change of Cell DTX activation / deactivation operation. As a result, the DCI format 2_9 may be an implicit trigger for OD-SSB transmissions / operations. While receiving the associating DCI format 2_9, the UE may assume that the SSB-less SCell will transmit its SSB based on a legacy pattern (e.g., with the same periodicity) if there is no further additional configuration and be able to perform relevant measurements. If the additional configuration is applied (e.g., together with the SCell serving configuration or together with the Cell DTX configuration), the UE may assume that the SSB will be transmitted in a configured way after receiving the DCI format 2_9 for the corresponding SCells. The configuration may include at least one of the following: the periodicity of SSB, the applied SSB index, the duration of SSB transmission, or the SSB transmission pattern, where the configuration is associated with the corresponding SCells. Additionally, an applied SSB pattern may be different for a deactivated SCell(s) and an activated SCell(s) with its corresponding Cell DTX activation state. An example is given in Table 1. 　　　　　　　　　　　　　　　　Table1: SSB patterns under different operations.

[0109] In some implementations, SSB pattern 1 may be sparer than SSB pattern 2, where SSB pattern 2 serves as a default pattern for a normal activated SCell.

[0110] In some implementations, SSB pattern 3 may be sparser than SSB pattern 1, as SSB pattern 3 may be designed specifically for measurement purposes during certain periods (e.g., the Cell DTX active time). Additionally, SSB pattern 3 may be sparser than SSB pattern 4.

[0111] In some implementations, SSB pattern 1 may be the same as pattern 2, but different from pattern 3 and 4.

[0112] In some implementations, all SSB patterns (e.g., SSB pattern 1, 2, 3, and 4 in Table 1) may be the same as default one or the same as a configured one.

[0113] In some implementations, a new field may be added to the DCI format 2_9 to indicate the corresponding SSB pattern for the corresponding SCell. In this case, more than one pattern may be configured for an operation state (e.g., an activated SCell with an activated cell DTX operation) and the DCI format 2_9 may dynamically indicate the SSB pattern. In some implementations, the pattern may be associated with the operation state and the existing DCI format 2_9 may be reused and the UE may implicitly determine the applied SSB pattern based on the state indicated by DCI format 2_9.

[0114] In some implementations, the gNB may resume the SSB transmission after sending the DCI format 2_9 and may terminate the SSB transmission based on gNB’s implementation or the configured pattern. The gNB may send another DCI format 2_9 to replace the previous indications and configure no SSB transmission as one of the SSB patterns. Thus, with the appropriate setting, the DCI format 2_9 may be used as termination signaling.

[0115] Fourth approach: using RRC signaling to indicate the SSB pattern and transmission in a case that the cell DTX (which is also referred to as cell DTX operation(s) in the present disclosure) is activated / deactivated.

[0116] In the fourth approach, a UE may be configured with a periodic cell DTX pattern separately or together with an (on-demand) SSB transmission pattern by a cell DTX configuration (e.g., the cellDTXConfig IE) via RRC signaling. For example, the RRC signaling may be considered as signaling for an OD-SSB triggering. In some implementations, the cell DTX and / or OD-SSB operations may be activated / deactivated in (one or any combinations of) the following ways:

[0117] (1) If the cell DTX operation is configured and the cell DTX activation status (e.g., the cellDTXactivationStatus IE) is set to activated, the cell DTX operation and / or SSB transmission pattern may be activated upon the reception of the cell DTX configuration. The cellDTXDRXactivationStatus IE may be included in the cellDTXConfig IE.

[0118] (2) If the cell DTX operation is configured and the cellDTXactivationStatus IE is set to deactivated, the cell DTX operation and / or SSB transmission pattern may be deactivated upon the UE receives the cell DTX configuration, where the cellDTXDRXactivationStatus IE may be included in the cellDTXConfig IE.

[0119] (3) If the cell DTX configuration is released, the cell DTX operation and / or SSB transmission pattern may be deactivated. In some implementations, the different secondary cells may be associated with different cellDTXactivationStatus IEs (e.g.,, one cellDTXactivationStatus IE may be associated with one specific secondary cell that is configured by the serving RAN, e.g., via RRC signaling). In some implementations, the cellDTXactivationStatus IE may be associated with a specific cell group (e.g., a master cell group, a secondary cell group or a group of secondary configured by the serving RAN). In some implementations, the cellDTXactivationStatus IE may be configured with a value of Need Maintain / Need Release / Need Specify.

[0120] (4) In some implementations, another IE (e.g., the CellDTXSSBStatus IE) included in an RRC message may be configured to further indicate that the concerned / target SSB patterns may be (automatically) associated with the cell DTX pattern. For example, if CellDTXSSBStatus= ‘CellDTX,’ it may mean that the concerned / target secondary cell would transmit SSB(s) automatically by jointly considering the given cell DTX pattern assocaited with the same secondary cell. In another condition, if CellDTXSSBStatus = ‘Broadcast’ or the CellDTXSSBStatus IE is absent in the received RRC signaling, it may mean that the concerned / target secondary cell would transmit an SSB set automatically / continuously regardless of whether the cell DTX operation is activated or deactivated.

[0121] In some implementations, for an SSB-less SCell, while receiving a cell DTX configuration via RRC signaling and the cellDTXactivationStatus IE is set to activated, the UE may assume that the SSB-less SCell may perform SSB transmissions based on a legacy pattern (same periodicity) if there is no further additional SSB pattern configuration and the UE may perform relevant measurement. If the additional SSB pattern configuration is applied / provided / configured (e.g., together with an SCell serving configuration or together with a cell DTX configuration), the UE may assume that the OD-SSB will be transmitted based on the configured SSB pattern after receiving the cell DTX configuration. The method of providing the SSB pattern configuration in the third approach may be applied to the fourth approach.

[0122] In some implementations, for an SSB-less SCell, when the UE receives the cell DTX configuration via RRC signaling, if the cellDTXactivationStatus IE is set to deactivated or the UE is indicated to release the cell DTX configuration, the UE may assume that the SSB-less SCell will terminate its SSB transmission or change its SSB transmission pattern. In some implementations, the UE may assume that the SSB transmission pattern will be changed if the additional SSB pattern configuration is applied (e.g., together with an SCell serving configuration or together with a cell DTX configuration). For example, the UE may assume that the OD-SSB will be transmitted based on the configured SSB pattern after receiving the cell DTX configuration.

[0123] FIG. 1 is a flowchart illustrating method / process 100 for handling OD-SSB receptions, according to an example implementation of the present disclosure. Although actions 102, 104, 106, and 108 are illustrated, as separate actions, represented as independent blocks in FIG. 1, these separately illustrated actions should not be construed as to be necessarily order-dependent. The order in which the actions are performed in FIG. 1 is not intended to be construed as a limitation, and any number of the disclosed blocks may be combined in any order to implement the method, or an alternative method. Each of actions 102, 104, 106, and 108 may be performed independent of the other actions, and may be omitted in some implementations of the present disclosure. Moreover, method / process 100 may be combined with other procedures / methods described in the present disclosure. Process 100 may be performed by a UE, with each action of process 100 corresponding to an operation executed by the UE.

[0124] In action 102, process 100 may start by receiving one or more RRC configurations. The one or more RRC configurations may indicate at least one of: at least one OD-SSB configuration identifier, at least one duration, at least one SSB index, or at least one periodicity.

[0125] In action 104, process 100 may receive a MAC CE including at least one field and at least one indication. The at least one indication may indicate at least one of: a subset of the at least one OD-SSB configuration identifier, a subset of the at least one duration, a subset of the at least one SSB index, or a subset of the at least one periodicity.

[0126] In action 106, in response to determining that a first field of the at least one field is set to a first value, process 100 may determine that an SSB transmission from a first cell corresponding to the first field is activated, and process 100 may receive an SSB from the first cell based on an SSB pattern corresponding to the first cell. In some implementations, the UE may determine the SSB pattern based on the RRC configuration and the at least one indication of the MAC CE in response to receiving the MAC CE. For example, the one or more RRC configurations may establish RRC parameters that include at least one OD-SSB configuration identifier, at least one duration, at least one SSB index, and / or at least one periodicity. The MAC CE may then specify which subset of the RRC parameters should be used for a specific cell (e.g., the first cell). In response to determining that a field in the MAC CE corresponding to the cell is set to a first value, the UE may know that the cell corresponding to the field will perform OD-SSB transmissions. The UE may then determine the SSB pattern for the cell by using the RRC parameter(s) specified by the MAC CE from within the set of RRC parameters configured through the one or more RRC configurations. For example, the UE may apply the SSB pattern to identify the resource locations of the SSB transmissions from the cell.

[0127] In action 108, in response to determining that the first field is set to a second value, process 100 may determine that the SSB transmission from the first cell is deactivated.

[0128] In some implementation, in response to determining that the SSB transmission from the first cell corresponding to the first field is activated, process 100 may perform an RRM measurement on the first cell. In response to determining that the SSB transmission from the first cell is deactivated, process 100 may forgo performing the RRM measurement on the first cell. For example, when the field (in the received MAC CE) corresponding to a cell is set to the second value, it indicates to the UE that the SSB transmission (e.g., the OD-SSB transmission) from that cell is deactivated. As a result, the UE may forgo performing the RRM measurement on this cell.

[0129] In some implementations, the at least one field may include multiple fields that include the first field, and each field of the multiple fields corresponds to a respective cell.

[0130] In some implementations, among cells corresponding to the multiple fields, a first portion of the cells supports an OD-SSB operation and a second portion of the cells does not support the OD-SSB operation.

[0131] In some implementations, the second portion of the cells includes a second cell corresponding to a second field of the multiple fields. The UE may maintain performing RRM measurements on the second cell regardless of whether the second field is set to the first value or the second value.

[0132] For example, consider a MAC CE containing at least 4 fields corresponding to cell#1, cell#2, cell#3, and cell#4, where cell#1 and cell#2 may support OD-SSB operation (first portion), while cell#3 and cell#4 may not support OD-SSB operation (second portion). When the field corresponding to cell#2 (e.g., the first field) is set to the first value, the UE may determine that the SSB transmission from cell#2 is activated. In this case, the UE may expect to receive SSBs from cell#2 after receiving the MAC CE, and consequently perform RRM measurement on cell#2 based on the specified SSB pattern. When this field is set to the second value, the UE may determine that the SSB transmission from cell#2 is deactivated. In this case, the UE may expect no SSB transmission from cell#2 and consequently forgo performing RRM measurement on cell#2. For cell#3 (e.g., the second cell) and cell#4 which do not support OD-SSB operation, the UE may maintain the RRM measurement for these cells, regardless of whether the fields corresponding to these cells (cell#3 and cell#4) are set to the first value or the second value.

[0133] In some implementations, all cells corresponding to the multiple fields may be Secondary Cells (SCells).

[0134] In some implementations, all cells corresponding to the multiple fields may support an OD-SSB operation.

[0135] In some implementations, each field of the at least one field is a 1-bit indicator.

[0136] Process 100 may enable effective control of OD-SSB receptions for a UE through a dynamic signaling mechanism. A MAC CE may be used to inform the UE whether an SSB transmission from a specific cell is activated or deactivated. In a case that the UE determines that the SSB transmission from a cell is activated, the UE may identify an SSB pattern for the upcoming OD-SSB receptions by combining pre-configured RRC parameters with a MAC CE parameter subset selection. This mechanism may provide the network with flexible control over OD-SSB transmissions while ensuring the UE may efficiently manage reception activities based on each cell’s OD-SSB transmission state.

[0137] It should also be noted that the BS may perform methods / actions corresponding to those performed by the UE. For example, the receiving actions performed by the UE may correspond to the transmitting / configuring actions of the BS; the transmitting actions performed by the UE may correspond to the receiving actions of the BS. That is, the BS and the UE may have reciprocally aligned roles in transmission and reception, as illustrated in FIG. 2.

[0138] FIG. 2 is a flowchart illustrating method / process 200 for handling OD-SSB transmissions, according to an example implementation of the present disclosure. Although actions 202, 204, 206, and 208 are illustrated, as separate actions, represented as independent blocks in FIG. 2, these separately illustrated actions should not be construed as to be necessarily order-dependent. The order in which the actions are performed in FIG. 2 is not intended to be construed as a limitation, and any number of the disclosed blocks may be combined in any order to implement the method, or an alternative method. Each of actions 202, 204, 206, and 208 may be performed independent of the other actions, and may be omitted in some implementations of the present disclosure. Moreover, method / process 200 may be combined with other procedures / methods described in the present disclosure. Process 200 may be performed by a BS, with each action of process 200 corresponding to an operation executed by the BS.

[0139] In action 202, process 200 may start by transmitting, to a UE, one or more RRC configurations. The one or more RRC configurations may indicate at least one of: at least one OD-SSB configuration identifier, at least one duration, at least one SSB index, or at least one periodicity.

[0140] In action 204, process 200 may transmit, to the UE, a MAC CE including at least one field and at least one indication. The at least one indication may indicate at least one of: a subset of the at least one OD-SSB configuration identifier, a subset of the at least one duration, a subset of the at least one SSB index, or a subset of the at least one periodicity.

[0141] In action 206, in response to setting a first field of the at least one field to a first value, process 200 may activate an SSB transmission by transmitting, based on an SSB pattern determined based on the RRC configuration and the MAC CE, at least one OD-SSB to the UE via a first cell corresponding to the first field for an RRM measurement.

[0142] In action 208, in response to setting the first field to a second value, process 200 may deactivate the SSB transmission by forgoing transmitting any OD-SSB to the UE via the first cell.

[0143] In some implementations, the at least one field may include multiple fields that include the first field, and each field of the multiple fields may correspond to a respective cell.

[0144] In some implementations, among cells corresponding to the multiple fields, a first portion of the cells may support an OD-SSB operation and a second portion of the cells may not support the OD-SSB operation.

[0145] In some implementations, the second portion of the cells may include a second cell corresponding to a second field of the multiple fields. The BS may set the second field to the first value and transmit an SSB to the UE via the second cell.

[0146] In some implementations, all cells corresponding to the multiple fields may be SCells.

[0147] In some implementations, all cells corresponding to the multiple fields may support an OD-SSB operation.

[0148] FIG. 3 is a block diagram illustrating node 300 for wireless communications, in accordance with various aspects of the present disclosure. As illustrated in FIG. 3, node 300 may include transceiver 320, processor 328, memory 334, one or more presentation components 338, and at least one antenna 336. Node 300 may also include a radio frequency (RF) spectrum band module, a BS communications module, a network communications module, and a system communications management module, Input / Output (I / O) ports, I / O components, and a power supply (not illustrated in FIG. 3).

[0149] Each of the components may directly or indirectly communicate with each other over one or more buses 340. Node 300 may be a UE or a BS that performs various functions disclosed with reference to FIG. 1 and FIG. 2.

[0150] Transceiver 320 has transmitter 322 (e.g., transmitting / transmission circuitry) and receiver 324 (e.g., receiving / reception circuitry) and may be configured to transmit and / or receive time and / or frequency resource partitioning information. Transceiver 320 may be configured to transmit in different types of subframes and slots including, but not limited to, usable, non-usable, and flexibly usable subframes and slot formats. Transceiver 320 may be configured to receive data and control channels.

[0151] Node 300 may include a variety of computer-readable media. Computer-readable media may be any available media that may be accessed by node 300 and include volatile (and / or non-volatile) media and removable (and / or non-removable) media.

[0152] The computer-readable media may include computer-storage media and communication media. Computer-storage media may include both volatile (and / or non-volatile media), and removable (and / or non-removable) media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules, or data.

[0153] Computer-storage media may include RAM, ROM, EPROM, EEPROM, flash memory (or other memory technology), CD-ROM, Digital Versatile Disks (DVD) (or other optical disk storage), magnetic cassettes, magnetic tape, magnetic disk storage (or other magnetic storage devices), etc. Computer-storage media may not include a propagated data signal. Communication media may typically embody computer-readable instructions, data structures, program modules, or other data in a modulated data signal, such as a carrier wave, or other transport mechanisms and include any information delivery media.

[0154] The term “modulated data signal” may mean a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. Communication media may include wired media, such as a wired network or direct-wired connection, and wireless media, such as acoustic, RF, infrared, and other wireless media. Combinations of any of the aforementioned listed components should also be included within the scope of computer-readable media.

[0155] Memory 334 may include computer-storage media in the form of volatile and / or non-volatile memory. Memory 334 may be removable, non-removable, or a combination thereof. Example memory may include solid-state memory, hard drives, optical-disc drives, etc. As illustrated in FIG. 3, memory 334 may store a computer-readable and / or computer-executable instructions 332 (e.g., software codes) that are configured to, when executed, cause processor 328 to perform various functions disclosed herein, for example, with reference to FIG. 1 and FIG. 2. Alternatively, instructions 332 may not be directly executable by processor 328 but may be configured to cause node 300 (e.g., when compiled and executed) to perform various functions disclosed herein.

[0156] Processor 328 (e.g., having processing circuitry) may include an intelligent hardware device, e.g., a Central Processing Unit (CPU), a microcontroller, an ASIC, etc. Processor 328 may include memory. Processor 328 may process data 330 and instructions 332 received from memory 334, and information transmitted and received via transceiver 320, the baseband communications module, and / or the network communications module. Processor 328 may also process information to send to transceiver 320 for transmission via antenna 336 to the network communications module for transmission to a CN.

[0157] One or more presentation components 338 may present data indications to a person or another device. Examples of presentation components 338 may include a display device, a speaker, a printing component, a vibrating component, etc.

[0158] In view of the present disclosure, it is obvious that various techniques may be used for implementing the disclosed concepts without departing from the scope of those concepts. Moreover, while the concepts have been disclosed with specific reference to certain implementations, a person of ordinary skill in the art may recognize that changes may be made in form and detail without departing from the scope of those concepts. As such, the disclosed implementations are to be considered in all respects as illustrative and not restrictive. It should also be understood that the present disclosure is not limited to the particular implementations disclosed and many rearrangements, modifications, and substitutions are possible without departing from the scope of the present disclosure.

Claims

1. A User Equipment (UE) for handling On-Demand Synchronization Signal Block (OD-SSB) receptions, the UE comprising: 　　　　at least one processor; and 　　　　at least one non-transitory computer-readable medium coupled to the at least one processor and storing one or more computer-executable instructions that, when executed by the at least one processor, cause the UE to: 　　　　receive one or more Radio Resource Control (RRC) configurations indicating at least one of: 　　　　　　　　at least one OD-SSB configuration identifier, 　　　　　　　　at least one duration, 　　　　　　　　at least one SSB index, or 　　　　　　　　at least one periodicity; 　　　　receive a Medium Access Control (MAC) Control Element (CE) comprising at least one field and at least one indication that indicates at least one of: 　　　　　　　　a subset of the at least one OD-SSB configuration identifier, 　　　　　　　　a subset of the at least one duration, 　　　　　　　　a subset of the at least one SSB index, or 　　　　　　　　a subset of the at least one periodicity; 　　　　in response to determining that a first field of the at least one field is set to a first value, determine that a Synchronization Signal Block (SSB) transmission from a first cell corresponding to the first field is activated, and receive an SSB from the first cell based on an SSB pattern corresponding to the first cell, wherein the SSB pattern is determined based on the RRC configuration and the MAC CE; and 　　　　in response to determining that the first field is set to a second value, determine that the SSB transmission from the first cell is deactivated.

2. The UE of claim 1, wherein the one or more computer-executable instructions, when executed by the at least one processor, further cause the UE to: 　　　　in response to determining that the SSB transmission from the first cell corresponding to the first field is activated, perform a Radio Resource Management (RRM) measurement on the first cell; and 　　　　in response to determining that the SSB transmission from the first cell is deactivated, forgo performing the RRM measurement on the first cell.

3. The UE of claim 1, wherein the at least one field comprises a plurality of fields including the first field, and each field of the plurality of fields corresponds to a respective cell.

4. The UE of claim 3, wherein among cells corresponding to the plurality of fields, a first portion of the cells supports an OD-SSB operation and a second portion of the cells does not support the OD-SSB operation.

5. The UE of claim 3, wherein all cells corresponding to the plurality of fields are Secondary Cells (SCells).

6. The UE of claim 3, wherein all cells corresponding to the plurality of fields support an OD-SSB operation.

7. The UE of claim 1, wherein the one or more computer-executable instructions, when executed by the at least one processor, further cause the UE to: 　　　　in response to receiving the MAC CE, determine the SSB pattern based on the RRC configuration and the at least one indication of the MAC CE.

8. The UE of claim 1, wherein each field of the at least one field is a 1-bit indicator.

9. A method of a User Equipment (UE) for handling On-Demand Synchronization Signal Block (OD-SSB) receptions, the method comprising: 　　　　receiving one or more Radio Resource Control (RRC) configurations indicating at least one of: 　　　　　　　　at least one OD-SSB configuration identifier, 　　　　　　　　at least one duration, 　　　　　　　　at least one SSB index, or 　　　　　　　　at least one periodicity; 　　　　receiving a Medium Access Control (MAC) Control Element (CE) comprising at least one field and at least one indication that indicates at least one of: 　　　　　　　　a subset of the at least one OD-SSB configuration identifier, 　　　　　　　　a subset of the at least one duration, 　　　　　　　　a subset of the at least one SSB index, or 　　　　　　　　a subset of the at least one periodicity; 　　　　in response to determining that a first field of the at least one field is set to a first value, determining that a Synchronization Signal Block (SSB) transmission from a first cell corresponding to the first field is activated, and receiving an SSB from the first cell based on an SSB pattern corresponding to the first cell, wherein the SSB pattern is determined based on the RRC configuration and the MAC CE; and 　　　　in response to determining that the first field is set to a second value, determining that the SSB transmission from the first cell is deactivated.

10. A Base Station (BS) comprising: 　　　　at least one processor; and 　　　　at least one non-transitory computer-readable medium coupled to the at least one processor and storing one or more computer-executable instructions that, when executed by the at least one processor, cause the BS to: 　　　　transmit, to a User Equipment (UE), one or more Radio Resource Control (RRC) configurations indicating at least one of: 　　　　　　　　at least one OD-SSB configuration identifier, 　　　　　　　　at least one duration, 　　　　　　　　at least one SSB index, or 　　　　　　　　at least one periodicity; 　　　　transmit, to the UE, a Medium Access Control (MAC) Control Element (CE) comprising at least one field and at least one indication that indicates at least one of: 　　　　　　　　a subset of the at least one OD-SSB configuration identifier, 　　　　　　　　a subset of the at least one duration, 　　　　　　　　a subset of the at least one SSB index, or 　　　　　　　　a subset of the at least one periodicity; 　　　　in response to setting a first field of the at least one field to a first value, activate a Synchronization Signal Block (SSB) transmission by transmitting, based on an SSB pattern determined based on the RRC configuration and the MAC CE, at least one OD-SSB to the UE via a first cell corresponding to the first field for a Radio Resource Management (RRM) measurement; and 　　　　in response to setting the first field to a second value, deactivate the SSB transmission by forgoing transmitting any OD-SSB to the UE via the first cell.

11. The BS of claim 10, wherein the at least one field comprises a plurality of fields including the first field, and each field of the plurality of fields corresponds to a respective cell.

12. The BS of claim 11, wherein among cells corresponding to the plurality of fields, a first portion of the cells supports an OD-SSB operation and a second portion of the cells does not support the OD-SSB operation.

13. The BS of claim 12, wherein the second portion of the cells comprises a second cell corresponding to a second field of the plurality of fields, and the one or more computer-executable instructions, when executed by the at least one processor, further cause the BS to: 　　　　set the second field to the first value; and 　　　　transmit an SSB to the UE via the second cell.

14. The BS of claim 11, wherein all cells corresponding to the plurality of fields are Secondary Cells (SCells).

15. The BS of claim 11, wherein all cells corresponding to the plurality of fields support an OD-SSB operation.

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