Method and apparatus for activating a secondary cell in a wireless communication system

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A method performed by a terminal in a wireless communication system, the method comprising: receiving, from a base station, information on a secondary cell (SCell) activation command; and in case that condition is met and the terminal is not provided with synchronization signal block (SSB) configuration nor SSB based measurement timing configuration (SMTC) for the SCell, activating the SCell within an activation time, wherein the terminal supports SCell without the SSB for inter band carrier aggregation (CA), and wherein the condition comprises at least one of information on a receiving timing difference (RTD) between the SCell and a reference cell, information on power difference of a symbol between the SCell and the reference cell, or information on a quasi co-location (QCL) associated with a reference signal (RS).

Description

METHOD AND APPARATUS FOR ACTIVATING A SECONDARY CELL IN A WIRELESS COMMUNICATION SYSTEM

[0001] The present disclosure relates to a communication field and specifically, to a user equipment (UE) and a method perform by the same, a network node and a method perform by the same, and a computer readable storage medium.

[0002] 5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in "Sub 6GHz" bands such as 3.5GHz, but also in "Above 6GHz" bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies.

[0003] At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service.

[0004] Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as V2X (Vehicle-to-everything) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.

[0005] Moreover, there has been ongoing standardization in air interface architecture / protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture / service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions.

[0006] As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with eXtended Reality (XR) for efficiently supporting AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.

[0007] Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using OAM (Orbital Angular Momentum), and RIS (Reconfigurable Intelligent Surface), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and AI (Artificial Intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of UE operation capability by utilizing ultra-high-performance communication and computing resources.

[0008] 5th generation (5G) or new radio (NR) mobile communications is recently gathering increased momentum with all the worldwide technical activities on the various candidate technologies from industry and academia. The candidate enablers for the 5G / NR mobile communications include massive antenna technologies, from legacy cellular frequency bands up to high frequencies, to provide beamforming gain and support increased capacity, new waveform (e.g., a new radio access technology (RAT)) to flexibly accommodate various services / applications with different requirements, new multiple access schemes to support massive connections, and so on.

[0009] In order to meet the increasing demand of wireless data communication services since the deployment of 4G communication systems, efforts have been made to develop improved 5G or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also called "Beyond 4G networks" or "Post-LTE systems".

[0010] In order to achieve a higher data rate, 5G communication systems are implemented at higher frequency (millimeter, mmWave) bands, e.g., 60GHz bands. In order to reduce propagation loss of radio waves and increase a transmission distance, technologies such as beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antenna, analog beamforming and large-scale antenna are discussed in 5G communication systems.

[0011] In addition, in 5G communication systems, developments of system network improvement are underway based on advanced small cell, cloud radio access network (RAN), ultra-dense network, device-to-device (D2D) communication, wireless backhaul, mobile network, cooperative communication, coordinated multi-points (CoMP), reception-end interference cancellation, etc.

[0012] In 5G systems, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) as advanced coding modulation (ACM), and filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies have been developed.

[0013] In line with development of the communication systems, there is a need for method for cell activation. The technical subjects pursued in the disclosure may not be limited to the above mentioned technical subjects, and other technical subjects which are not mentioned may be clearly understood, through the following descriptions, by those skilled in the art to which the disclosure pertains.

[0014] The present disclosure provides a UE, a network node, methods thereof and a storage medium. A method performed by a UE includes: receiving, from a network node, a command to activate or de-activate a secondary cell; activating or de-activating the secondary cell, wherein if the user equipment is not provided with synchronization signal / physical broadcast channel block (SS / PBCH block, SSB) configuration nor SSB measurement timing configuration (SMTC) for the secondary cell, activation or de-activation delay requirement of the secondary cell is associated with at least one of a frequency separation between the secondary cell and a reference cell, a relative frequency separation between the secondary cell and the reference cell, whether or not the secondary cell and the reference cell use a same radio frequency (RF) unit module in the network node, whether or not the secondary cell and the reference cell use a same receive link at the user equipment, carrier frequencies of the secondary cell and the reference cell, a difference in path loss between the secondary cell and the reference cell, frequency band(s) in which the secondary cell and the reference cell are located, capability information of the user equipment, and grouping information of the secondary cell.

[0015] According to the first aspect of the embodiments of the present disclosure, there is provided a method performed by a user equipment in a communication system, including: receiving, from a network node, a command to activate or de-activate a secondary cell; activating or de-activating the secondary cell, wherein if the user equipment is not provided with synchronization signal / physical broadcast channel block (SS / PBCH block, SSB) configuration nor SSB measurement timing configuration (SMTC) for the secondary cell, activation or de-activation delay requirement of the secondary cell is associated with at least one of a frequency separation between the secondary cell and a reference cell, a relative frequency separation between the secondary cell and the reference cell, whether or not the secondary cell and the reference cell use a same radio frequency (RF) unit module in the network node, whether or not the secondary cell and the reference cell use a same receive link at the user equipment, carrier frequencies of the secondary cell and the reference cell, a difference in path loss between the secondary cell and the reference cell, frequency band(s) in which the secondary cell and the reference cell are located, capability information of the user equipment, and grouping information of the secondary cell.

[0016] Alternatively, the method further includes: reporting the capability information to the network node, wherein the capability information includes at least one of: first capability information indicating that the user equipment supports that the secondary cell does not carry a SSB in an intra-band carrier aggregation scenario and an inter-band carrier aggregation scenario; second capability information indicating that the user equipment supports that the secondary cell does not carry a SSB in an intra-band non-contiguous carrier aggregation scenario; third capability information indicating that the user equipment supports that the secondary cell does not carry a SSB in the inter-band carrier aggregation scenario; fourth capability information indicating that the user equipment supports that the secondary cell whose frequency separation and / or relative frequency separation with the reference cell satisfies a first condition does not carry a SSB.

[0017] Alternatively, the reference cell is determined from among serving cells of the user equipment based on a first rule or information indicating the reference cell received by the user equipment from the network node, wherein the serving cells include a primary cell or a special cell and an activated secondary cell that carries a SSB.

[0018] Alternatively, the first rule includes at least one of: determining the reference cell based on frequency separation(s) between the secondary cell and the serving cells; determining the reference cell based on relative frequency separation(s) between the secondary cell and the serving cells; and determining the reference cell based on signal quality / power of the serving cells.

[0019] Alternatively, the determining of the reference cell based on the frequency separation(s) between the secondary cell and the serving cells includes: selecting a serving cell with the smallest frequency separation as the reference cell, or selecting a serving cell with a frequency separation greater than a first threshold as the reference cell, wherein the first threshold is a threshold configured by a network node or predefined; the determining of the reference cell based on the relative frequency separation(s) between the secondary cell and the serving cells includes: selecting a serving cell with the smallest relative frequency separation as the reference cell, or selecting a serving cell with a relative frequency separation greater than a second threshold as the reference cell, wherein the second threshold is a threshold configured by the network node or predefined; the determining of the reference cell based on the signal quality / power of the serving cells includes: selecting a serving cell with the greatest signal quality / power as the reference cell, or selecting a serving cell with the signal quality / power greater than a third threshold as the reference cell, wherein the third threshold is a threshold configured by the network node or predefined.

[0020] Alternatively, the capability information is reported per a component carrier (CC), or per a combination of multiple CCs, or per a user equipment.

[0021] Alternatively, the grouping information is configured by the network node or determined according to at least one of: the frequency separation between the secondary cell and the reference cell, the relative frequency separation between the secondary cell and the reference cell, whether or not the secondary cell and the reference cell use the same RF unit module in the network node, whether or not the secondary cell and the reference cell use the same receive link at the user equipment, the carrier frequencies of the secondary cell and the reference cell, the difference in the path loss between the secondary cell and the reference cell, and the frequency band(s) in which the secondary cell and the reference cell are located.

[0022] Alternatively, the activation or de-activation delay requirement includes at least one of: a requirement regarding a receive timing difference of the secondary cell from the reference cell; a requirement regarding a difference of the reception power between the secondary cell and the reference cell; a requirement regarding a type of quasi-co-location relationship between a reference signal and a tracking reference signal of the secondary cell, and a requirement regarding a type of quasi-co-location relationship between a tracking reference signal of the secondary cell and a SSB of the reference cell.

[0023] Alternatively, a time alignment error of the network node is associated with at least one of the frequency separation between the secondary cell and the reference cell, the relative frequency separation between the secondary cell and the reference cell, whether or not the secondary cell and the reference cell uses the same RF unit module in the network node, the carrier frequencies of the secondary cell and the reference cell, the difference in the path loss between the secondary cell and the reference cell, the frequency band(s) in which the secondary cell and the reference cell are located.

[0024] According to the first aspect of the embodiments of the present disclosure, there is provided a method performed by a network node in a communication system, including: receiving capability information reported by a user equipment; and transmitting, to the user equipment, a command to activate or de-activate a secondary cell; wherein if the user equipment is not provided with synchronization signal / physical broadcast channel block (SS / PBCH block, SSB) configuration nor SSB measurement timing configuration (SMTC) for the secondary cell, activation or de-activation delay requirement of the secondary cell is associated with at least one of a frequency separation between the secondary cell and a reference cell, a relative frequency separation between the secondary cell and the reference cell, whether or not the secondary cell and the reference cell use a same radio frequency (RF) unit module in the network node, whether or not the secondary cell and the reference cell use a same receive link at the user equipment, carrier frequencies of the secondary cell and the reference cell, a difference in path loss between the secondary cell and the reference cell, frequency band(s) in which the secondary cell and the reference cell are located, capability information of the user equipment, and grouping information of the secondary cell.

[0025] Alternatively, the capability information includes at least one of: first capability information indicating that the user equipment supports that the secondary cell does not carry a SSB in an intra-band carrier aggregation scenario and an inter-band carrier aggregation scenario; second capability information indicating that the user equipment supports that the secondary cell does not carry a SSB in an intra-band non-contiguous carrier aggregation scenario; third capability information indicating that the user equipment supports that the secondary cell does not carry a SSB in the inter-band carrier aggregation scenario; fourth capability information indicating that the user equipment supports that the secondary cell whose frequency separation and / or relative frequency separation with the reference cell satisfies a first condition does not carry a SSB.

[0026] Alternatively, the method further includes: transmitting, to the user equipment, information indicating the reference cell, wherein the reference cell is determined based on the information indicating the reference cell.

[0027] Alternatively, the reference cell is determined from among serving cells of the user equipment based on at least one of frequency separation(s) between the secondary cell and the serving cells, relative frequency separation(s) between the secondary cell and the serving cells and signal quality / power of the serving cells, wherein the serving cells include a primary cell or a special cell and an activated secondary cell that carries a SSB.

[0028] Alternatively, the reference cell is a serving cell with the smallest frequency separation, or the reference cell is a serving cell with a frequency separation greater than a first threshold, wherein the first threshold is a threshold configured by a network node or predefined; or

[0029] the reference cell is a serving cell with the smallest relative frequency separation, or the reference cell is a serving cell with a relative frequency separation greater than a second threshold, wherein the second threshold is a threshold configured by the network node or predefined; or

[0030] the reference cell is a serving cell with the greatest signal quality / power , or the reference cell is a serving cell with the signal quality / power greater than a third threshold, wherein the third threshold is a threshold configured by the network node or predefined.

[0031] Alternatively, the capability information is reported per a component carrier (CC), or per a combination of multiple CCs, or per a user equipment.

[0032] Alternatively, the grouping information is configured by the network node or determined according to at least one of: the frequency separation between the secondary cell and the reference cell, the relative frequency separation between the secondary cell and the reference cell, whether or not the secondary cell and the reference cell use the same RF unit module in the network node, whether or not the secondary cell and the reference cell use the same receive link at the user equipment, the carrier frequencies of the secondary cell and the reference cell, the difference in the path loss between the secondary cell and the reference cell, and the frequency band(s) in which the secondary cell and the reference cell are located.

[0033] Alternatively, the activation or de-activation delay requirement includes at least one of: a requirement regarding a receive timing difference of the secondary cell from the reference cell; a requirement regarding a difference of the reception power between the secondary cell and the reference cell; a requirement regarding a type of quasi-co-location relationship between a reference signal and a tracking reference signal of the secondary cell, and a requirement regarding a type of quasi-co-location relationship between a tracking reference signal of the secondary cell and a SSB of the reference cell.

[0034] Alternatively, a time alignment error of the network node is associated with at least one of the frequency separation between the secondary cell and the reference cell, the relative frequency separation between the secondary cell and the reference cell, whether or not the secondary cell and the reference cell uses the same RF unit module in the network node, the carrier frequencies of the secondary cell and the reference cell, the difference in the path loss between the secondary cell and the reference cell, the frequency band(s) in which the secondary cell and the reference cell are located.

[0035] According to a third aspect of an embodiment of the present disclosure, there is provided a user equipment, the user equipment includes: a transceiver; a processor coupled to the transceiver and configured to perform the above method performed by the user equipment.

[0036] According to a fourth aspect of an embodiment of the present disclosure, there is provided a network node, the network node includes: a transceiver; a processor coupled to the transceiver and configured to perform the above method performed by the network node.

[0037] According to a fifth aspect of an embodiment of the present disclosure, there is provided a computer readable storage medium storing instructions that, when executed by at least one processor, cause the at least one processor to perform any one of the above methods.

[0038] According to the technical solutions provided by the embodiments of the present disclosure, if the user equipment is not provided with SSB configuration nor SMTC for the Scell, since activation or de-activation delay requirement of the secondary cell is associated with at least one of a frequency separation between the secondary cell and a reference cell, a relative frequency separation between the secondary cell and the reference cell, whether or not the secondary cell and the reference cell use a same radio frequency (RF) unit module in the network node, whether or not the secondary cell and the reference cell use a same receive link at the user equipment, carrier frequencies of the secondary cell and the reference cell, a difference in path loss between the secondary cell and the reference cell, frequency band(s) in which the secondary cell and the reference cell are located, capability information of the user equipment, and grouping information of the secondary cell, even if the user equipment is not provided with SSB configuration nor SMTC for the secondary cell, the user equipment is still able to correctly execute the activation or de-activation of the SCell, thereby effectively avoiding the occupation of excessive time and frequency resources due to the SSB configuration and the SMTC, which brings about a better network energy saving effect and can ensure that the activation or de-activation of the SCell is performed correctly while saving energy in the network.

[0039] It should be understood that the above general descriptions and the following detailed descriptions are only illustrative and explanatory, and do not limit the present disclosure.

[0040] The present disclosure provides an effective and efficient method for activating an SCell. Advantageous effects obtainable from the disclosure may not be limited to the above mentioned effects, and other effects which are not mentioned may be clearly understood, through the following descriptions, by those skilled in the art to which the disclosure pertains.

[0041] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing exemplary embodiments in accordance with the present disclosure and used together with the specification to explain the principles of the present disclosure, and do not constitute an improper limitation of the present disclosure.

[0042] FIG. 1 illustrates an example wireless network 100 according to various embodiments of the present disclosure;

[0043] FIG. 2a and FIG.2b illustrate an example wireless transmission path and an example wireless reception path according to the present disclosure;

[0044] FIG. 3a illustrates an example UE 116 according to the present disclosure;

[0045] FIG. 3b illustrates an example gNB 102 according to the present disclosure;

[0046] FIG. 4 is a flowchart illustrating a method performed by a user equipment according to embodiments of the present disclosure;

[0047] FIG. 5 is a flowchart illustrating an example of a method performed by a user equipment according to an embodiment of the present disclosure;

[0048] FIG. 6 is a flowchart illustrating a method performed by a network node according to embodiments of the present disclosure;

[0049] FIG. 7 is a schematic diagram illustrating an example of communication between a user equipment and a network node according to embodiments of the present disclosure;

[0050] FIG. 8 is a block diagram illustrating a user equipment according to embodiments of the present disclosure;

[0051] FIG. 9 is a block diagram illustrating a network node according to embodiments of the present disclosure.

[0052] The description is provided below with reference to the accompanying drawings to facilitate comprehensive understanding of various embodiments of the present disclosure as defined by the claims and the equivalents thereof. This description includes various specific details to help with understanding but should only be considered illustrative. Consequently, those ordinarily skilled in the art will realize that various embodiments described here can be varied and modified without departing from the scope and spirit of the present disclosure. In addition, the description of function and structure of the common knowledge may be omitted for clarity and conciseness.

[0053] The terms and expressions used in the claims and the description below are not limited to their lexicographical meaning but are used only by the inventor to enable the clear and consistent understanding of the present disclosure. Therefore, it should be apparent to those skilled in the art that the following description of the various embodiments of the present disclosure is provided only for the purpose of the illustration without limiting the present disclosure as defined by the appended claims and their equivalents.

[0054] It will be understood that, unless specifically stated, the singular forms "one", "a", and "the" used herein may also include the plural form. Thus, for example, "component surface" refers to one or more such the surfaces.

[0055] The terms "includes" and "may include" mean the presentation of the corresponding disclosed functions, operations, or components that can be used in various embodiments of the present disclosure, but do not limit the presentation of one or more additional functions, operations, or features. In addition, it should be understood that the terms "including" or "having" may be interpreted to mean certain features, numbers, steps, operations, components, assemblies or combinations thereof, but should not be interpreted to exclude the possibility of the existence of one or more of other features, numbers, steps, operations, components, assemblies and / or combinations thereof.

[0056] The term "or" used in various embodiments of the disclosure herein includes any listed term and all combinations thereof. For example, "A or B" may include A, or include B, or include both A and B.

[0057] Unless defined differently, all terms as used in the present disclosure (including technical or scientific terms) have the same meanings as understood by those skilled in the art as described in the present disclosure. As common terms defined in dictionaries are interpreted to have meanings consistent with those in the context in the relevant technical field, and they should not be idealized or overly formalized unless expressly defined as such in the present disclosure.

[0058] Exemplary embodiments of the present disclosure are further described below in conjunction with the accompanying drawings. The text and accompanying drawings are provided as examples only to assist the reader in understanding the present disclosure. They are not intended to and should not be construed as limiting the scope of the present disclosure in any way. Although certain embodiments and examples have been provided, based on what is disclosed herein, it will be apparent to those skilled in the art that changes may be made to the illustrated embodiments and examples without departing from the scope of the present disclosure.

[0059] FIG. 1 illustrates an example wireless network 100 according to various embodiments of the present disclosure. The embodiment of the wireless network 100 shown in FIG. 1 is for illustration only. Other embodiments of the wireless network 100 may be used without departing from the scope of the present disclosure.

[0060] The wireless network 100 includes a gNodeB (gNB) 101, a gNB 102, and a gNB 103. gNB 101 communicates with gNB 102 and gNB 103. gNB 101 also communicates with at least one Internet Protocol (IP) network 130, such as the Internet, a private IP network, or other data networks.

[0061] Depending on a type of the network, other well-known terms such as "base station" or "access point" may be used instead of "gNodeB" or "gNB". For convenience, the terms "gNodeB" and "gNB" are used in this patent document to refer to network infrastructure components that provide wireless access for remote terminals. And, depending on the type of the network, other well-known terms such as "mobile station", "user station", "remote terminal", "wireless terminal" or "user apparatus" may be used instead of "user equipment" or "UE". For convenience, the terms "user equipment" and "UE" are used in this patent document to refer to remote wireless devices that wirelessly access the gNB, no matter whether the UE is a mobile device (such as a mobile phone or a smart phone) or a fixed device (such as a desktop computer or a vending machine).

[0062] gNB 102 provides wireless broadband access to the network 130 for a first plurality of User Equipments (UEs) within a coverage area 120 of gNB 102. The first plurality of UEs include a UE 111, which may be located in a Small Business (SB); a UE 112, which may be located in an enterprise (E); a UE 113, which may be located in a WiFi Hotspot (HS); a UE 114, which may be located in a first residence (R); a UE 115, which may be located in a second residence (R); a UE 116, which may be a mobile device (M), such as a cellular phone, a wireless laptop computer, a wireless PDA, etc. GNB 103 provides wireless broadband access to network 130 for a second plurality of UEs within a coverage area 125 of gNB 103. The second plurality of UEs include a UE 115 and a UE 116. In some embodiments, one or more of gNBs 101-103 can communicate with each other and with UEs 111-116 using 5G, Long Term Evolution (LTE), LTE-A, WiMAX or other advanced wireless communication technologies.

[0063] The dashed lines show approximate ranges of the coverage areas 120 and 125, and the ranges are shown as approximate circles merely for illustration and explanation purposes. It should be clearly understood that the coverage areas associated with the gNBs, such as the coverage areas 120 and 125, may have other shapes, including irregular shapes, depending on configurations of the gNBs and changes in the radio environment associated with natural obstacles and man-made obstacles.

[0064] As will be described in more detail below, one or more of gNB 101, gNB 102, and gNB 103 include a 2D antenna array as described in embodiments of the present disclosure. In some embodiments, one or more of gNB 101, gNB 102, and gNB 103 support codebook designs and structures for systems with 2D antenna arrays.

[0065] Although FIG. 1 illustrates an example of the wireless network 100, various changes may be made to FIG. 1. The wireless network 100 can include any number of gNBs and any number of UEs in any suitable arrangement, for example. Furthermore, gNB 101 can directly communicate with any number of UEs and provide wireless broadband access to the network 130 for those UEs. Similarly, each gNB 102-103 can directly communicate with the network 130 and provide direct wireless broadband access to the network 130 for the UEs. In addition, gNB 101, 102 and / or 103 can provide access to other or additional external networks, such as external telephone networks or other types of data networks.

[0066] FIGs. 2a and 2b illustrate example wireless transmission and reception paths according to the present disclosure. In the following description, the transmission path 200 may be described as being implemented in a gNB, such as gNB 102, and the reception path 250 may be described as being implemented in a UE, such as UE 116. However, it should be understood that the reception path 250 may be implemented in a gNB and the transmission path 200 may be implemented in a UE. In some embodiments, the reception path 250 is configured to support codebook designs and structures for systems with 2D antenna arrays as described in embodiments of the present disclosure.

[0067] The transmission path 200 includes a channel coding and modulation block 205, a Serial-to-Parallel (S-to-P) block 210, a size N Inverse Fast Fourier Transform (IFFT) block 215, a Parallel-to-Serial (P-to-S) block 220, a cyclic prefix addition block 225, and an up-converter (UC) 230. The reception path 250 includes a down-converter (DC) 255, a cyclic prefix removal block 260, a Serial-to-Parallel (S-to-P) block 265, a size N Fast Fourier Transform (FFT) block 270, a Parallel-to-Serial (P-to-S) block 275, and a channel decoding and demodulation block 280.

[0068] In the transmission path 200, the channel coding and modulation block 205 receives a set of information bits, applies coding (such as Low Density Parity Check (LDPC) coding), and modulates the input bits (such as using Quadrature Phase Shift Keying (QPSK) or Quadrature Amplitude Modulation (QAM)) to generate a sequence of frequency domain modulated symbols. The Serial-to-Parallel (S-to-P) block 210 converts (such as demultiplexes) serial modulated symbols into parallel data to generate N parallel symbol streams, where N is a size of the IFFT / FFT used in gNB 102 and UE 116. The size N IFFT block 215 performs IFFT operations on the N parallel symbol streams to generate a time domain output signal. The Parallel-to-Serial block 220 converts (such as multiplexes) parallel time domain output symbols from the Size N IFFT block 215 to generate a serial time domain signal. The cyclic prefix addition block 225 inserts a cyclic prefix into the time domain signal. The up-converter 230 modulates (such as up-converts) the output of the cyclic prefix addition block 225 to an RF frequency for transmission via a wireless channel. The signal can also be filtered at a baseband before switching to the RF frequency.

[0069] The RF signal transmitted from gNB 102 arrives at UE 116 after passing through the wireless channel, and operations in reverse to those at gNB 102 are performed at UE 116. The down-converter 255 down-converts the received signal to a baseband frequency, and the cyclic prefix removal block 260 removes the cyclic prefix to generate a serial time domain baseband signal. The Serial-to-Parallel block 265 converts the time domain baseband signal into a parallel time domain signal. The Size N FFT block 270 performs an FFT algorithm to generate N parallel frequency domain signals. The Parallel-to-Serial block 275 converts the parallel frequency domain signal into a sequence of modulated data symbols. The channel decoding and demodulation block 280 demodulates and decodes the modulated symbols to recover the original input data stream.

[0070] Each of gNBs 101-103 may implement a transmission path 200 similar to that for transmitting to UEs 111-116 in the downlink, and may implement a reception path 250 similar to that for receiving from UEs 111-116 in the uplink. Similarly, each of UEs 111-116 may implement a transmission path 200 for transmitting to gNBs 101-103 in the uplink, and may implement a reception path 250 for receiving from gNBs 101-103 in the downlink.

[0071] Each of the components in FIGs. 2a and 2b may be implemented using only hardware, or using a combination of hardware and software / firmware. As a specific example, at least some of the components in FIGs. 2a and 2b may be implemented in software, while other components may be implemented in configurable hardware or a combination of software and configurable hardware. For example, the FFT block 270 and IFFT block 215 may be implemented as configurable software algorithms, in which the value of the size N may be modified according to the implementation.

[0072] Furthermore, although described as using FFT and IFFT, this is only illustrative and should not be interpreted as limiting the scope of the present disclosure. Other types of transforms may be used, such as Discrete Fourier transform (DFT) and Inverse Discrete Fourier Transform (IDFT) functions. It should be understood that for DFT and IDFT functions, the value of variable N may be any integer (such as 1, 2, 3, 4, etc.), while for FFT and IFFT functions, the value of variable N may be any integer which is a power of 2 (such as 1, 2, 4, 8, 16, etc.).

[0073] Although FIGs. 2a and 2b illustrate examples of wireless transmission and reception paths, various changes may be made to FIGs. 2a and 2b. For example, various components in FIGs. 2a and 2b may be combined, further subdivided or omitted, and additional components may be added according to specific requirements. Furthermore, FIGs. 2a and 2b are intended to illustrate examples of types of transmission and reception paths that may be used in a wireless network. Any other suitable architecture may be used to support wireless communication in a wireless network.

[0074] FIG. 3a illustrates an example UE 116 according to the present disclosure. The embodiment of UE 116 shown in FIG. 3a is for illustration only, and UEs 111-115 of FIG. 1 can have the same or similar configuration. However, a UE has various configurations, and FIG. 3a does not limit the scope of the present disclosure to any specific implementation of the UE.

[0075] UE 116 includes an antenna 305, a radio frequency (RF) transceiver 310, a transmission (TX) processing circuit 315, a microphone 320, and a reception (RX) processing circuit 325. UE 116 also includes a speaker 330, a processor / controller 340, an input / output (I / O) interface 345, an input device(s) 350, a display 355, and a memory 360. The memory 360 includes an operating system (OS) 361 and one or more applications 362.

[0076] The RF transceiver 310 receives an incoming RF signal transmitted by a gNB of the wireless network 100 from the antenna 305. The RF transceiver 310 down-converts the incoming RF signal to generate an intermediate frequency (IF) or baseband signal. The IF or baseband signal is transmitted to the RX processing circuit 325, where the RX processing circuit 325 generates a processed baseband signal by filtering, decoding and / or digitizing the baseband or IF signal. The RX processing circuit 325 transmits the processed baseband signal to speaker 330 (such as for voice data) or to processor / controller 340 for further processing (such as for web browsing data).

[0077] The TX processing circuit 315 receives analog or digital voice data from microphone 320 or other outgoing baseband data (such as network data, email or interactive video game data) from processor / controller 340. The TX processing circuit 315 encodes, multiplexes, and / or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The RF transceiver 310 receives the outgoing processed baseband or IF signal from the TX processing circuit 315 and up-converts the baseband or IF signal into an RF signal transmitted via the antenna 305.

[0078] The processor / controller 340 can include one or more processors or other processing devices and execute an OS 361 stored in the memory 360 in order to control the overall operation of UE 116. For example, the processor / controller 340 can control the reception of forward channel signals and the transmission of backward channel signals through the RF transceiver 310, the RX processing circuit 325 and the TX processing circuit 315 according to well-known principles. In some embodiments, the processor / controller 340 includes at least one microprocessor or microcontroller.

[0079] The processor / controller 340 is also capable of executing other processes and programs residing in the memory 360, such as operations for channel quality measurement and reporting for systems with 2D antenna arrays as described in embodiments of the present disclosure. The processor / controller 340 can move data into or out of the memory 360 as required by an execution process. In some embodiments, the processor / controller 340 is configured to execute the application 362 based on the OS 361 or in response to signals received from the gNB or the operator. The processor / controller 340 is also coupled to an I / O interface 345, where the I / O interface 345 provides UE 116 with the ability to connect to other devices such as laptop computers and handheld computers. I / O interface 345 is a communication path between these accessories and the processor / controller 340.

[0080] The processor / controller 340 is also coupled to the input device(s) 350 and the display 355. An operator of UE 116 can input data into UE 116 using the input device(s) 350. The display 355 may be a liquid crystal display or other display capable of presenting text and / or at least limited graphics (such as from a website). The memory 360 is coupled to the processor / controller 340. A part of the memory 360 can include a random access memory (RAM), while another part of the memory 360 can include a flash memory or other read-only memory (ROM).

[0081] Although FIG. 3a illustrates an example of UE 116, various changes may be made to FIG. 3a. For example, various components in FIG. 3a may be combined, further subdivided or omitted, and additional components may be added according to specific requirements. As a specific example, the processor / controller 340 may be divided into a plurality of processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). Furthermore, although FIG. 3a illustrates that the UE 116 is configured as a mobile phone or a smart phone, UEs may be configured to operate as other types of mobile or fixed devices.

[0082] FIG. 3b illustrates an example gNB 102 according to the present disclosure. The embodiment of gNB 102 shown in FIG. 3b is for illustration only, and other gNBs of FIG. 1 can have the same or similar configuration. However, a gNB has various configurations, and FIG. 3b does not limit the scope of the present disclosure to any specific implementation of a gNB. It should be noted that gNB 101 and gNB 103 can include the same or similar structures as gNB 102.

[0083] As shown in FIG. 3b, gNB 102 includes a plurality of antennas 370a-370n, a plurality of RF transceivers 372a-372n, a transmission (TX) processing circuit 374, and a reception (RX) processing circuit 376. In certain embodiments, one or more of the plurality of antennas 370a-370n include a 2D antenna array. gNB 102 also includes a controller / processor 378, a memory 380, and a backhaul or network interface 382.

[0084] RF transceivers 372a-372n receive an incoming RF signal from antennas 370a-370n, such as a signal transmitted by UEs or other gNBs. RF transceivers 372a-372n down-convert the incoming RF signal to generate an IF or baseband signal. The IF or baseband signal is transmitted to the RX processing circuit 376, where the RX processing circuit 376 generates a processed baseband signal by filtering, decoding and / or digitizing the baseband or IF signal. RX processing circuit 376 transmits the processed baseband signal to controller / processor 378 for further processing.

[0085] The TX processing circuit 374 receives analog or digital data (such as voice data, network data, email or interactive video game data) from the controller / processor 378. TX processing circuit 374 encodes, multiplexes and / or digitizes outgoing baseband data to generate a processed baseband or IF signal. RF transceivers 372a-372n receive the outgoing processed baseband or IF signal from TX processing circuit 374 and up-convert the baseband or IF signal into an RF signal transmitted via antennas 370a-370n.

[0086] The controller / processor 378 can include one or more processors or other processing devices that control the overall operation of gNB 102. For example, the controller / processor 378 can control the reception of forward channel signals and the transmission of backward channel signals through the RF transceivers 372a-372n, the RX processing circuit 376 and the TX processing circuit 374 according to well-known principles. The controller / processor 378 can also support additional functions, such as higher-layer wireless communication functions. For example, the controller / processor 378 can perform a Blind Interference Sensing (BIS) process such as that performed through a BIS algorithm, and decode a received signal from which an interference signal is subtracted. A controller / processor 378 may support any of a variety of other functions in gNB 102. In some embodiments, the controller / processor 378 includes at least one microprocessor or microcontroller.

[0087] The controller / processor 378 is also capable of executing programs and other processes residing in the memory 380, such as a basic OS. The controller / processor 378 can also support channel quality measurement and reporting for systems with 2D antenna arrays as described in embodiments of the present disclosure. In some embodiments, the controller / processor 378 supports communication between entities such as web RTCs. The controller / processor 378 can move data into or out of the memory 380 as required by an execution process.

[0088] The controller / processor 378 is also coupled to the backhaul or network interface 382. The backhaul or network interface 382 allows gNB 102 to communicate with other devices or systems through a backhaul connection or through a network. The backhaul or network interface 382 can support communication over any suitable wired or wireless connection(s). For example, when gNB 102 is implemented as a part of a cellular communication system, such as a cellular communication system supporting 5G or new radio access technology or NR, LTE or LTE-A, the backhaul or network interface 382 can allow gNB 102 to communicate with other gNBs through wired or wireless backhaul connections. When gNB 102 is implemented as an access point, the backhaul or network interface 382 can allow gNB 102 to communicate with a larger network, such as the Internet, through a wired or wireless local area network or through a wired or wireless connection. The backhaul or network interface 382 includes any suitable structure that supports communication through a wired or wireless connection, such as an Ethernet or an RF transceiver.

[0089] The memory 380 is coupled to the controller / processor 378. A part of the memory 380 can include an RAM, while another part of the memory 380 can include a flash memory or other ROMs. In certain embodiments, a plurality of instructions, such as the BIS algorithm, are stored in the memory. The plurality of instructions are configured to cause the controller / processor 378 to execute the BIS process and decode the received signal after subtracting at least one interference signal determined by the BIS algorithm.

[0090] As will be described in more detail below, the transmission and reception paths of gNB 102 (implemented using RF transceivers 372a-372n, TX processing circuit 374 and / or RX processing circuit 376) support aggregated communication with FDD cells and TDD cells.

[0091] Although FIG. 3b illustrates an example of gNB 102, various changes may be made to FIG. 3b. For example, gNB 102 can include any number of each component shown in FIG. 3a. As a specific example, the access point can include many backhaul or network interfaces 382, and the controller / processor 378 can support routing functions to route data between different network addresses. As another specific example, although shown as including a single instance of the TX processing circuit 374 and a single instance of the RX processing circuit 376, gNB 102 can include multiple instances of each (such as one for each RF transceiver).

[0092] With the continuous development of a wireless communication system, a network needs to use more antennas, more bandwidth, and more frequency bands in order to achieve a higher data rate, and a high energy cost has gradually become one of the challenges for operators. Meanwhile, in 5G NR, a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH) together form a Synchronization Signal Block (SS / PBCH block, SSB), which is mainly used for downlink synchronization and measurement. The SSB appears several times in a half-frame at regular intervals, and these SSBs form a Synchronization Signal Block set (SSB set), which may have a period of, for example, 5ms, 10ms, 20ms, 40ms, 80ms, 160ms, etc. However, transmitting these SSBs takes up a lot of time and frequency resources, which consumes a lot of energy of the network.

[0093] With respect to this, the present disclosure proposes a conception capable of realizing network energy saving. Specifically, according to the conception of the present disclosure, at least one user equipment, a method performed by a user equipment, a network node, and a method performed by a network node are provided.

[0094] In a wireless network, in order to support a wider transmission bandwidth for the purpose of increasing a data rate of a single user equipment, two or more component carriers (CCs) are assigned to the same user equipment for data transmission, and this aggregation of the component carriers is called Carrier Aggregation (CA). That multiple component carriers are in the same frequency band and their spectra are continuous, which is called intra-band contiguous CA; that multiple component carriers are in the same frequency band and there is a certain interval between their spectra, which is called intra-band non-contiguous CA; that multiple component carriers are in different frequency bands, which is called inter-band CA. Multiple cells united by the CA technology form a cell group, in which a cell used to initiate an initial access is a Primary Cell (PCell) or a Special Cell (SpCell), and the other cells in the cell group, except for the PCell or the SpCell, are Secondary Cells (SCells).

[0095] The conception proposed in the present disclosure that realizes network energy saving may be applied at least for network energy saving in intra-band contiguous carrier aggregation, intra-band non-contiguous carrier aggregation, and / or inter-band carrier aggregation scenarios.

[0096] In the following, the conception of the present disclosure will be described in detail with reference to FIGS. 4 through 9.

[0097] FIG. 4 is a flowchart illustrating a method performed by a user equipment according to embodiments of the present disclosure.

[0098] Referring to FIG. 4, at step S410, a command to activate or de-activate a SCell is received from a network node. As an example, the network node may be any network device (e.g., a base station device, a sidelink device, etc.), or a network functional entity. For example, the user equipment may receive a Media Access Control-Control Element (MAC-CE) signaling from the network node to know which SCell or SCells to be activated or de-activated.

[0099] Next, at step S420, the SCell is activated or de-activated. According to embodiments, if the user equipment is not provided with synchronization signal / physical broadcast channel block (SS / PBCH block, SSB) configuration nor SSB measurement timing configuration (SMTC) for the secondary cell, activation or de-activation delay requirement of the SCell is associated with at least one of a frequency separation between the SCell and a reference cell, a relative frequency separation between the SCell and the reference cell, whether or not the SCell and the reference cell use a same radio frequency (RF) unit module in the network node, whether or not the SCell and the reference cell use a same receive link at the user equipment, carrier frequencies of the SCell and the reference cell, a difference in path loss between the SCell and the reference cell, frequency band(s) in which the SCell and the reference cell are located, capability information of the user equipment, and grouping information of the SCell.

[0100] For example, the frequency separation between the SCell and the reference cell may be defined as a frequency separation between a SCell CC and a reference cell CC, or a frequency separation between the SCell CC and a frequency band in which the reference cell CC is located. The frequency separation between the SCell CC and the reference cell CC may be defined as one of: a difference between an upper frequency edge of the SCell CC and a lower frequency edge of the reference cell CC, a difference between a center frequency of the SCell CC and a center frequency of the reference cell CC, a difference between the upper frequency edge of the SCell CC and an upper frequency edge of the reference cell CC, a difference between a lower frequency edge of the SCell CC and the lower frequency edge of the reference cell CC, and a difference between the lower frequency edge of the SCell CC and the upper frequency edge of the reference cell CC. If the SCell CC and the reference cell CC are in the same frequency band, a frequency separation between the frequency bands in which the SCell CC and the reference cell CC are located may be defined as one of: a difference between an upper frequency edge of a CC with the highest frequency and a lower frequency edge of a CC with the lowest frequency in the same frequency band, a difference between a center frequency of the CC with the highest frequency and a center frequency of the CC with the lowest frequency in the same frequency band, a difference between the upper frequency edge of the CC with the highest frequency and an upper frequency edge of the CC with the lowest frequency in the same frequency band, a difference between a lower frequency edge of the CC with the highest frequency and the lower frequency edge of the CC with the lowest frequency in the same frequency band, and a difference between the lower frequency edge of the CC with the highest frequency and the upper frequency edge of the CC with the lowest frequency in the same frequency band. If the SCell CC and the reference cell CC are in different frequency bands, frequency separation(s) between the frequency bands in which the SCell CC and the reference cell CC are located may be defined as one of: a difference between an upper frequency edge of a CC with the highest frequency in a frequency band with the highest frequency and a lower frequency edge of a CC with the lowest frequency in a frequency band with the lowest frequency, a difference between a center frequency of the CC with the highest frequency in the frequency band with the highest frequency and a center frequency of the CC with the lowest frequency in the frequency band with the lowest frequency, a difference between the upper frequency edge of the CC with the highest frequency in the frequency band with the highest frequency and an upper frequency edge of the CC with the lowest frequency in the frequency band with the lowest frequency, a difference between a lower frequency edge of the CC with the highest frequency in the frequency band with the highest frequency and the lower frequency edge of the CC with the lowest frequency in the frequency band with the lowest frequency, a difference between the lower frequency edge of the CC with the highest frequency in the frequency band with the highest frequency and the lower frequency edge of the CC with the lowest frequency in the frequency band with the lowest frequency, but not limited to thereto.

[0101] For example, the relative frequency separation between the SCell and the reference cell may be defined as one of: dividing the frequency separation between the SCell CC and the reference cell CC by an upper frequency edge or a center frequency or a lower frequency edge of a CC of the SCell, dividing the frequency separation between the SCell and the reference cell by an upper frequency edge or a center frequency or a lower frequency edge of a CC of the reference cell, dividing the frequency separation between the SCell and the reference cell by an upper frequency edge or a center frequency or a lower frequency edge of a CC with the highest or lowest frequency in the frequency band in which the SCell is located, and dividing the frequency separation between the SCell and the reference cell by an upper frequency edge or a center frequency or a lower frequency edge of a CC with the highest or lowest frequency in the frequency band in which the reference cell is located, but not limited thereto.

[0102] Optionally, the method shown in FIG. 4 further includes: reporting capacity information to the network node. According to embodiments, the capability information includes at least one of: first capability information indicating that the user equipment supports that the SCell does not carry a SSB in an intra-band carrier aggregation scenario and an inter-band carrier aggregation scenario; second capability information indicating that the user equipment supports that the SCell does not carry a SSB in an intra-band non-contiguous carrier aggregation scenario; third capability information indicating that the user equipment supports that the SCell does not carry a SSB in the inter-band carrier aggregation scenario; fourth capability information indicating that the user equipment supports that the SCell whose frequency separation and / or relative frequency separation with the reference cell satisfies a first condition does not carry a SSB. In the present disclosure, the SCell not carrying a SSB may mean that the SCell does not have a SSB configuration and does not have a SSB measurement timing configuration (SMTC). According to embodiments, if the user equipment reports the fourth capability information, it indicates that the user equipment supports that the SCell whose frequency separation and / or relative frequency separation with the reference cell satisfies the first condition does not carry a SSB, while that the user equipment supports that the SCell whose frequency separation and / or relative frequency separation with the reference cell satisfies the first condition does not carry a SSB, and it may implicitly indicate that the user equipment supports that the SCell does not carry a SSB in an intra-band non-contiguous carrier aggregation scenario and / or an inter-band carrier aggregation scenario. Here, the frequency separation and / or the frequency separation with the reference cell, and the first condition may be predefined.

[0103] For example, the first condition may be that the frequency separation between the SCell and the reference cell is less than or equal to a first predetermined value, and / or, the first condition may be that the relative frequency separation between the SCell and the reference cell is less than or equal to a second predetermined value, but not limited thereto.

[0104] According to embodiments, the capability information may be reported per a component carrier (CC), or per a combination of multiple CCs, or per a user equipment. For example, if the capability information is reported per the CC, it indicates that the user equipment has a capability indicated by the capability information on that CC. If the capability information is reported per the combination of CCs, it indicates that the user equipment has a capability indicated by the capability information on that combination of CCs. If the capability information is reported per the user equipment, it indicates that the user equipment has a capability indicated by the capability information on any CC and any combination of CCs.

[0105] According to embodiments, the reference cell may provide a reference to the SCell regarding at least one of timing difference information, frequency difference information and channel state information. The user equipment may provide a reference for timing difference and / or frequency difference and / or channel state information to the SCell that does not have a SSB configuration and does not have a SSB measurement timing configuration (SMTC) using information of the reference cell, to perform activation or de-activation of the SCell.

[0106] According to embodiments, the reference cell is determined from among serving cells of the user equipment based on a first rule or information indicating the reference cell received by the user equipment from the network node. For example, the serving cells include a primary or special cell and an activated SCell carrying a SSB. The information indicating the reference cell is hereinafter also referred to as "first information". In the present disclosure, the SCell carrying a SSB may be a SCell with a SSB configuration or with a SSB measurement timing configuration (SMTC), whereas the SCell without a SSB configuration and without a SSB measurement timing configuration (SMTC) may be referred to simply as a SCell not carrying a SSB.

[0107] For example, determining the reference cell may have the following three alternative schemes:

[0108] In a first scheme, the user equipment selects a reference cell based on information indicating the reference cell received from a network node. For example, the information may directly indicate which cell or cells are the reference cell(s) for the SCell, such that the user equipment may directly determine the reference cell(s) by means of the information.

[0109] In a second scheme, the user equipment determines a reference cell based on the first rule. According to embodiments, the first rule may include at least one of: determining the reference cell based on frequency separation(s) between the Scell and the serving cells; determining the reference cell based on relative frequency separation(s) between the Scell and the serving cells; and determining the reference cell based on signal quality / power of the serving cells. It is noted that the first rule may include at least one of the above items, meaning that the reference cell may be determined based on at least one of the frequency separation, the relative frequency separation, and the signal quality / power , and is not limited to determining the reference cell based only on the frequency separation, the relative frequency separation, or the signal quality / power . For example, the reference cell may be determined based on the frequency separation and the signal quality / power , e.g., a plurality of cells may first be selected from the serving cells based on the frequency separation, and then the reference cell may be determined from the plurality of cells based on the signal quality / power of the plurality of cells.

[0110] For example, determining the reference cell based on the frequency separation may include: selecting a serving cell with the smallest frequency separation as the reference cell, or selecting a serving cell with a frequency separation greater than a first threshold as the reference cell, wherein the first threshold is a threshold configured by a network node or predefined. For example, determining the reference cell based on the relative frequency separation may include: selecting a serving cell with the smallest relative frequency separation as the reference cell, or selecting a serving cell with a relative frequency separation greater than a second threshold as the reference cell, wherein the second threshold is a threshold configured by the network node or predefined. For example, determining the reference cell based on the signal quality / power of the serving cells may include: selecting a serving cell with the greatest signal quality / power as the reference cell, or selecting a serving cell with the signal quality / power greater than a third threshold as the reference cell, wherein the third threshold is a threshold configured by the network node or predefined. For example, the user equipment may select a reference cell for a SCell that does not carry a SSB among activated cells of a current cell group based on the first rule. For example, an activated cell with the smallest carrier frequency separation and / or relative frequency separation with a SCell not carrying a SSB in the same cell group is selected as the reference cell, or the reference cell may be selected in accordance with the principle of the largest signal quality / power (e.g., RSRP / SINR / RSRQ), or it may be selected in accordance with a predefined threshold, and an activated cell carrying a SSB that satisfies the requirement of the predefined threshold is the reference cell.

[0111] In a third scheme, the user equipment determines a reference cell based on both the first rule and the information indicating the reference cell. For example, the user equipment first determines a reference cell by means of the information indicating the reference cell, and then the user equipment may change the reference cell again according to the first rule in accordance with changes of activated cells in a cell group.

[0112] According to embodiments, the activation or de-activation delay requirement of the SCell is not only related to the frequency separation between the Scell and the reference cell, the relative frequency separation between the Scell and the reference cell, whether or not the Scell and the reference cell use the same RF unit module in the network node, whether or not the Scell and the reference cell use the same receive link at the user equipment, the carrier frequencies of the Scell and the reference cell, the difference in the path loss between the Scell and the reference cell, the frequency band(s) in which the Scell and the reference cell are located, the capability information of the user equipment, and the grouping information of the Scell, bur also related to the capability information of the user equipment and / or the grouping information of the SCell.

[0113] According to embodiments, the grouping information may be configured by the network node or determined according to at least one of: the frequency separation between the Scell and the reference cell, the relative frequency separation between the Scell and the reference cell, whether or not the Scell and the reference cell use the same RF unit module in the network node, whether or not the Scell and the reference cell use the same receive link at the user equipment, the carrier frequencies of the Scell and the reference cell, the difference in the path loss between the Scell and the reference cell, and the frequency band(s) in which the Scell and the reference cell are located. For example, the grouping information may be obtained based on second information received from the network node, or the grouping information is obtained based on a predefined grouping rule. For example, the grouping information may be indicated to the user equipment by the network node by means of the second information, or, the grouping information may be obtained based on a predefined grouping rule that the user equipment uses the same grouping rule as the network node.

[0114] According to embodiments, the grouping rule may be grouping of a SCell based on at least one of: the frequency separation between the Scell and the reference cell, the relative frequency separation between the Scell and the reference cell, whether or not the Scell and the reference cell use the same RF unit module in the network node, whether or not the Scell and the reference cell use the same receive link at the user equipment, the carrier frequencies of the Scell and the reference cell, the difference in the path loss between the Scell and the reference cell, and the frequency band(s) in which the Scell and the reference cell are located. For example, the grouping of the SCell based on the carrier frequencies of the SCell and the reference cell may include grouping of the SCell based on a carrier frequency ratio between the SCell and the reference cell, and the grouping of the SCell based on the frequency band(s) in which the SCell and the reference cell are located may include grouping of the SCell based on a combination of the frequency bands in which the SCell is located and the reference cell is located.

[0115] For example, the SCell may be grouped into a first group (denoted by SetA), a second group (denoted by SetB), a third group (denoted by SetC), or a fourth group (SetD group), and the like, based on the frequency separation between the SCell, which does not carry a SSB, and the reference cell. For example, if the SCell is grouped into SetA, it is necessary to satisfy that the frequency separation between the SCell and the reference cell does not exceed a first value, and there are various possibilities for the value of the first value, for example, the value may be taken as 200MHz; if the SCell is grouped into SetB, it is necessary to satisfy that the frequency separation between the SCell and the reference cell is greater than the first value and does not exceed a second value, and there are various possibilities for the value of the second value, for example, the value of the second value may be taken as 600MHz; if the SCell is grouped into SetC, it is necessary to satisfy that the frequency separation between the SCell and the reference cell is greater than the second value and does not exceed a third value, and there are various possibilities for the value of the third value, for example, the value may be taken as 1200MHz; if the SCell is grouped into SetD, it is necessary to satisfy that the frequency separation between the SCell and the reference cell is greater than the third value. This is shown in Table 1 below.

[0116]

[0117] As an example, the frequency separation between the SCell and the reference cell may be defined as one of: a frequency separation between a SCell CC and a reference cell CC, a frequency separation between frequency bands in which the SCell CC and the reference cell CC are located. The frequency separation between the SCell CC and the reference cell CC may be defined as one of: a difference between an upper frequency edge of the SCell CC and a lower frequency edge of the reference cell CC, a difference between a center frequency of the SCell CC and a center frequency of the reference cell CC, a difference between the upper frequency edge of the SCell CC and an upper frequency edge of the reference cell CC, a difference between a lower frequency edge of the SCell CC and the lower frequency edge of the reference cell CC and a difference between the lower frequency edge of the SCell CC and the upper frequency edge of the reference cell CC. If the SCell CC and the reference cell CC are in the same frequency band, a frequency separation between the frequency bands in which the SCell CC and the reference cell CC are located may be defined as one of: a difference between an upper frequency edge of a CC with the highest frequency and a lower frequency edge of a CC with the lowest frequency in the same frequency band, a difference between a center frequency of the CC with the highest frequency and a center frequency of the CC with the lowest frequency in the same frequency band, a difference between the upper frequency edge of the CC with the highest frequency and an upper frequency edge of the CC with the lowest frequency in the same frequency band, a difference between a lower frequency edge of the CC with the highest frequency and the lower frequency edge of the CC with the lowest frequency in the same frequency band, and a difference between the lower frequency edge of the CC with the highest frequency and the upper frequency edge of the CC with the lowest frequency in the same frequency band. If the SCell CC and the reference cell CC are in different frequency bands, the frequency separation between the frequency bands in which the SCell CC and the reference cell CC are located may be defined as one of: a difference between an upper frequency edge of a CC with the highest frequency in a frequency band with the highest frequency and a lower frequency edge of a CC with the lowest frequency in a frequency band with the lowest frequency, a difference between a center frequency of the CC with the highest frequency in the frequency band with the highest frequency and a center frequency of the CC with the lowest frequency in the frequency band with the lowest frequency, a difference between the upper frequency edge of the CC with the highest frequency in the frequency band with the highest frequency and an upper frequency edge of the CC with the lowest frequency in the frequency band with the lowest frequency, a difference between a lower frequency edge of the CC with the highest frequency in the frequency band with the highest frequency and the lower frequency edge of the CC with the lowest frequency in the frequency band with the lowest frequency, a difference between the lower frequency edge of the CC with the highest frequency in the frequency band with the highest frequency and the lower frequency edge of the CC with the lowest frequency in the frequency band with the lowest frequency.

[0118] For another example, the SCell may be grouped into a first group (denoted by SetA), a second group (denoted by SetB), a third group (denoted by SetC), or a fourth group (SetD group) based on the relative frequency separation between the SCell and the reference cell. For example, if the SCell is grouped into SetA, it is necessary to satisfy that the relative frequency separation between the SCell and the reference cell does not exceed a fourth value, and there are various possibilities for the value of the fourth value, for example, it may be taken as the value of 0.2; if the SCell is grouped into SetB, it is necessary to satisfy that the relative frequency separation between the SCell and the reference cell is greater than the fourth value and does not exceed a fifth value, and there are various possibilities for the value of the fifth value, for example, it may be taken as the value of 0.3; if the SCell is grouped to SetC, it is necessary to satisfy that the relative frequency separation between the SCell and the reference cell is greater than the fifth value and does not exceed a sixth value, and there are various possibilities for the value of the sixth value, for example, the value may be taken as the value of 0.6; if the SCell is grouped to SetD, it is necessary to satisfy that the relative frequency separation between the SCell and the reference cell is greater than the sixth value. This is shown in the table below.

[0119]

[0120] As an example, the relative frequency separation between the SCell and the reference cell may be defined as one of: dividing the frequency separation between the SCell CC and the reference cell CC by an upper frequency edge or a center frequency or a lower frequency edge of a CC of the SCell, dividing the frequency separation between the SCell and the reference cell by an upper frequency edge or a center frequency or a lower frequency edge of a CC of the reference cell, dividing the frequency separation between the SCell and the reference cell by an upper frequency edge or a center frequency or a lower frequency edge of a CC with the highest or lowest frequency in the frequency band in which the SCell is located, and dividing the frequency separation between the SCell and the reference cell by an upper frequency edge or a center frequency or a lower frequency edge of a CC with the highest or lowest frequency in the frequency band in which the reference cell is located

[0121] As another example, the grouping may also be based directly on a combination of the frequency bands in which the SCell and the reference cell are located. For example, it is assumed that the combination of the frequency bands is a combination in an intra-band non-contiguous carrier aggregation scenario, the grouping may be performed as shown in Table 3A below. For example, it is assumed that the combination of the frequency bands is a combination of two frequency bands, the grouping may be performed as shown in Table 3B below.

[0122]

[0123]

[0124] In Table 3A and Table 3B, n denotes a frequency band number. CA_nX(*) denotes an intra-band non-contiguous carrier aggregation for a frequency band nX. n1, n3 is a combination of NR frequency bands in which the SCell and the reference cell are located, and CA_n1-n3 is a combination of NR carrier aggregation frequency bands in which the SCell the reference cell are located, and the SCell is grouped to SetA if combination of NR frequency bands in which the SCell and the reference cell are located is n1, n3 and the combination of NR carrier aggregation frequency bands in which the SCell and the reference cell are located is CA_n1-n3, then the SCell is grouped to SetA.

[0125] According to embodiments, the activation or de-activation delay requirement may include at least one of: a requirement regarding a receive timing difference (RTD) of the Scell from the reference cell; a requirement regarding a difference of the reception power between the Scell and the reference cell; a requirement regarding a type of quasi-co-location relationship between a reference signal and a tracking reference signal of the Scell, and a requirement regarding a type of quasi-co-location relationship between a tracking reference signal of the Scell and a SSB of the reference cell.

[0126] As an example, the activation or de-activation delay requirement may be a minimum requirement for the activation or de-activation delay, but is not limited thereto.

[0127] According to embodiments, as described above, the activation or de-activation delay requirement of the SCell may be associated with the capability information of the user equipment and / or the grouping information of the SCell, if the user equipment is not provided with SSB configuration nor SMTC for the Scell. For example, different groups and / or different capabilities of the user equipment may correspond to different minimum requirements for the activation or de-activation delay.

[0128] For example, the minimum requirement may be described by the following Table 4 and may include one or more columns in Table 4, or may include one or more rows in Table 4. Wherein, in Table 4, different groups correspond to different minimum requirements for activation or de-activation delay.

[0129]

[0130] Optionally, the minimum requirement described above may also be described in Table 5 below, and may include one or more columns in Table 5, or may include one or more rows in Table 5. In Table 5, this minimum requirement may be indicated by a requirement index, and different requirement indexes may correspond to different RTD minimum requirements and receive power difference minimum requirements.

[0131]

[0132] In Table 5 above, for example, groups SetA, SetB, SetC, and SetD may correspond to requirement indexes 0, 1, 2, and 3, respectively. i.e., different groups may correspond to different minimum requirements for activation or de-activation. Alternatively, different capabilities of the user equipment to support the SCell not carrying a SSB may correspond to different minimum requirements for activation or de-activation, e.g., if the user equipment reports a first capability information, it indicates that the user equipment supports that the Scell does not carry a SSB in an intra-band carrier aggregation scenario and an inter-band carrier aggregation scenario, in which case the minimum requirement may be a requirement index of 3; and for example , if the user equipment reports a second capability information, it indicates that the user equipment supports that the Scell does not carry a SSB in an intra-band non-contiguous carrier aggregation scenario, in which case the minimum requirement may be a requirement index of 0. Usually, the stronger the capability of the user equipment to support the SCell not to carry a SSB is, the wider the minimum requirement may be, and the weaker the capability of the user equipment to support the SCell not to carry a SSB is, the more stringent the minimum requirement may be.

[0133] Optionally, the above minimum requirement may also be described by the following table 6, which may, for example, include one or more columns in table 6, or may include one or more rows in table 6.

[0134]

[0135] In Table 6, the grouping of the SCell that does not carry a SSB may be determined based on the second through fourth columns, and different groups may correspond to different requirement indexes. Optionally, while considering the grouping, the above capability information may be further considered to determine a minimum requirement for the activation or de-activation delay of the SCell not carrying a SSB. Optionally, this minimum requirement may also be determined based on the capability information only, or based on the grouping information only.

[0136] It is noted that RTD and difference of the reception power are parameters that may affect the activation or de-activation delay Tactivation_time, however, the parameters affecting the of activation or de-activation delay are not limited to the RTD and the difference of the reception power, and therefore, the activation or de-activation delay requirement is not limited to include the above examples, but may be a requirement regarding any parameter that may affect the activation or de-activation delay.

[0137] According to embodiments, the requirement regarding the RTD and / or the requirement regarding the difference of the reception power may affect the activation delay Tactivation_timeof the SCell, or may also not affect the activation delay Tactivation_timeof the SCell.

[0138] For example, if a SCell to be activated belongs to FR1 and has a reference cell that is in an activated state, if the user equipment is not provided with synchronization signal / physical broadcast channel block (SS / PBCH block, SSB) configuration nor SSB measurement timing configuration (SMTC) for the secondary cell, and if the user equipment has a capability indicated by either of the first capability information through the fourth capability information above, the activation delay Tactivation_timeof the SCell is X, X having various possible values, e.g. 3ms, if the following conditions are met:

[0139] - When the SCell belongs to the group SetA or SetB or SetC or SetD or when the user equipment has a different capability to support the SCells not to carry a SSB, the receive timing difference (RTD) between the SCell and the reference cell is within a range of Y, and Y has different values corresponding to different groups, and there are various possible values, such as ±260ns; such as ±min(a cyclic prefix length, 3μs), wherein the cyclic prefix is a cyclic prefix corresponding to the maximum subcarrier interval between the SCell and the reference cell; and such as ±(3μs + Y1), there are various possible values of Y1;

[0140] - The difference of the reception power between the SCell and the reference cell is in a range of Z. There are various possible values for Z, such as 6dB + Z1, and Z1 has different values corresponding to different groups, such as 0dB;

[0141] - The reference signal of the SCell is in a quasi-co-location relationship of TypeA with the tracking reference signal (TRS), and the TRS of the SCell is in a quasi-co-location relationship of TypeC with the SSB of the reference cell.

[0142] For example, if a SCell to be activated belongs to FR1 and has a reference cell that is in an activated state, if the user equipment is not provided with SSB configuration nor SMTC for the Scell, and if the user equipment has a capability indicated by either of the first capability information through the fourth capability information above, the activation delay Tactivation_timeof the SCell is X1, X1 having various possible values, e.g. 3ms, if the following conditions are met:

[0143] - When the SCell belongs to the group SetA or when the user equipment has the capability to support the SCell not to carry a SSB, the RTD between the SCell and the reference cell is within a range of Y, there are various possible values for Y, such as ±260ns;

[0144] - The difference of the reception power between the SCell and the reference cell is in a range of Z, there are various possible values for Z, such as 6dB+Z1, and Z1 has different values corresponding to different groups, such as 0dB;

[0145] - The reference signal of the SCell is in a quasi-co-location relationship of TypeA with the tracking reference signal (TRS), and the TRS of the SCell is in a quasi-co-location relationship of TypeC with the SSB of the reference cell.

[0146] For example, if a SCell to be activated belongs to FR1 and has a reference cell that is in an activated state, if the user equipment is not provided with SSB configuration nor SMTC for the Scell, and if the user equipment has a capability indicated by either of the first capability information through the fourth capability information above, the activation delay Tactivation_timeof the SCell is X2, X2 having various possible values, e.g. 3ms, if the following conditions are met:

[0147] - When the SCell belongs to the group SetB or when the user equipment has the capability to support the SCell not to carry a SSB, the RTD between the SCell and the reference cell is within a range of Y, there are various possible values for Y, such as ±min (a cyclic prefix length, 3μs), wherein the cyclic prefix is a cyclic prefix corresponding to the maximum subcarrier interval between the SCell and reference cell;

[0148] - The difference of the reception power between the SCell and the reference cell is in a range of Z, there are various possible values for Z, such as 6dB+Z1, and Z1 has different values corresponding to different groups, such as 0dB;

[0149] - The reference signal of the SCell is in a quasi-co-location relationship of TypeA with the tracking reference signal (TRS), and the TRS of the SCell is in a quasi-co-location relationship of TypeC with the SSB of the reference cell.

[0150] For example, if a SCell to be activated belongs to FR1 and has a reference cell that is in an activated state, if the user equipment is not provided with SSB configuration nor SMTC for the Scell, and if the user equipment has a capability indicated by either of the first capability information through the fourth capability information above, the activation delay Tactivation_timeof the SCell is X3, X3 having various possible values, e.g. 3ms, if the following conditions are met:

[0151] - When the SCell belongs to the group SetC or SetD or when the user equipment has the capability to support the SCell not to carry a SSB, the RTD between the SCell and the reference cell is within a range of Y, there are various possible values for Y, such as （3μs + Y1）, and there are various possible values of Y1;

[0152] - The difference of the reception power between the SCell and the reference cell is in a range of Z. There are various possible values for Z, such as 6dB + Z1, and Z1 has different values corresponding to different groups, such as 0dB;

[0153] - The reference signal of the SCell is in a quasi-co-location relationship of TypeA with the tracking reference signal (TRS), and the TRS of the SCell is in a quasi-co-location relationship of TypeC with the SSB of the reference cell.

[0154] The values of X1, X2, X3 above may be different or the same.

[0155] Optionally, according to embodiments, a Time Alignment Error (TAE) of the network node may be associated with at least one of: the frequency separation between the Scell and the reference cell, the relative frequency separation between the Scell and the reference cell, whether or not the Scell and the reference cell uses the same RF unit module in the network node, the carrier frequencies of the Scell and the reference cell, the difference in the path loss between the Scell and the reference cell, the frequency band(s) in which the Scell and the reference cell are located. For example, the requirement with respect to the TAE may be determined based on at least one of the above information, or based on the grouping information, wherein the grouping information is determined based on at least one of the above information. For example, for intra-band non-contiguous carrier aggregation and / or inter-band carrier aggregation, the SCells not carrying a SSB may be grouped according to different frequency separation(s) and / or relative frequency separation(s) with or without multiple inputs and multiple outputs, and the TAE of the network node may have different minimum requirements corresponding to different groups. For example, corresponding to the aforementioned group SetA or SetB or SetC or SetD, the TAE should be within a time M. M has different values corresponding to different groups and there are various possible values of M, such as 260 ns; such as min(a cyclic prefix length, 3μs), wherein the cyclic prefix is a cyclic prefix corresponding to the largest subcarrier interval in a carrier component of carrier aggregation; such as 3μs, etc.

[0156] According to embodiments, the requirement with respect to the receive timing difference may be affected only by the TAE of the network node, or the requirement with respect to the receive timing difference may be further affected by other factors in addition to the TAE of the network node, to which the present disclosure is not limited.

[0157] According to embodiments, step S420 may include: determining an activation or de-activation delay requirement for the SCell based on at least one of: a frequency separation between the SCell and a reference cell, a relative frequency separation between the SCell and the reference cell, whether or not the SCell and the reference cell uses a same RF unit module in the network node, whether or not the SCell and the reference cell uses a same receive link in the user equipment, carrier frequencies of the SCell and the reference cell, a difference in path loss between the SCell and the reference cell, frequency band(s) in which the SCell and the reference cell are located, capability information of the user equipment, and grouping information of the SCell; and activating or de-activating the SCell upon satisfying the activation or de-activation delay requirement. For example, the SCell is activated or de-activated using the information of the reference cell in the case of satisfying the activation or de-activation delay requirements. As an example, the information of the reference cell may include, without limitation, at least one of: timing difference information of the reference cell, frequency difference information of the reference cell and channel state information of the reference cell.

[0158] In above, the method performed by a user equipment according to the present disclosure has been described with reference to FIG. 4, and according to the method, when there is no SSB configuration for a SCell and there is no SMTC, since the activation or de-activation delay requirement of the SCell is associated with at least one of: the frequency separation between the SCell and the reference cell, the relative frequency separation between the SCell and the reference cell, whether or not the SCell and the reference cell use the same RF unit module in the network node, whether or not the SCell and the reference cell use the same receive link in the user equipment, the carrier frequencies of the SCell and the reference cell, the difference in the path loss between the Scell and the reference cell, the frequency band(s) in which the SCell and the reference cell are located, and the capability information of the user equipment, the grouping information of the SCell, even if the user equipment is not provided with SSB configuration nor SMTC for the Scell, the user equipment is still able to correctly execute the activation or de-activation of the SCell, thereby effectively avoiding the occupation of excessive time and frequency resources due to the SSB configuration and the SMTC, which brings about a better network energy saving effect and can ensure that the activation or de-activation of the SCell is performed correctly while saving energy in the network. Further, if the activation or de-activation delay requirement of the SCell is associated with the grouping information and / or the capability information, the activation or de-activation delay requirement may be separately formulated for SCells belonging to different groups and / or having different capability information, thereby avoiding unnecessary waiting time, and better achieving the purpose of reducing the network delay, increasing the system throughput, and saving energy in the network.

[0159] To facilitate understanding of the above method, one example of the method shown in FIG. 4 is briefly described. FIG. 5 is a flowchart illustrating an example of a method performed by a user equipment according to an embodiment of the present disclosure.

[0160] Referring to FIG. 5, at step S510, the user equipment reports capability information. The capability information has been described above and will not be repeated herein.

[0161] Next, at step S520, the user equipment determines a reference cell based on a first rule and / or first information received by the user equipment from the network node. For example, the reference cell is selected from a primary cell or a special cell and an activated SCell carrying a SSB, based on the first rule and / or the first information.

[0162] Subsequently, at step S530, the user equipment determines grouping information based on second information received from the network node and / or a predefined grouping rule and determines an activation or de-activation delay requirement for the SCell based on the grouping information and / or the capability information.

[0163] Finally, at step S540, the user equipment performs the activation or de-activation of the SCell using information of the reference cell in the case that the activation or de-activation delay requirement is satisfied.

[0164] Above, the method performed by the user equipment has been described with reference to FIGS. 4 and 5, and below, a method performed by the network node will be described with reference to FIG. 6. In the present disclosure, the network node may be is any network device (e.g., a base station device, a sidelink device, etc.), or a network functional entity.

[0165] Referring to FIG. 6, at step S610, capability information reported by the user equipment is received. According to embodiments, the capability information may include at least one of: first capability information indicating that the user equipment supports that the Scell does not carry a SSB in an intra-band carrier aggregation scenario and an inter-band carrier aggregation scenario; second capability information indicating that the user equipment supports that the Scell does not carry a SSB in an intra-band non-contiguous carrier aggregation scenario; third capability information indicating that the user equipment supports that the Scell does not carry a SSB in the inter-band carrier aggregation scenario; fourth capability information indicating that the user equipment supports that the Scell whose frequency separation and / or relative frequency separation with the reference cell satisfies a first condition does not carry a SSB, which have been described above in the description of FIG. 4 with respect to the capability information, and all of the descriptions of the capability information in the above may be applicable to the method shown in FIG. 6, therefore they are not repeated here. According to the embodiment, when the user equipment reports the above capability information, the SSB configuration and the SMTC may not be performed for the SCell of the user equipment.

[0166] Next, at step S620, a command to activate or de-activate the SCell is transmitted to the user equipment. According to embodiments, the activation or de-activation delay requirement of the SCell may be associated with at least one of: a frequency separation between the Scell and a reference cell, a relative frequency separation between the Scell and the reference cell, whether or not the Scell and the reference cell use a same radio frequency (RF) unit module in the network node, whether or not the Scell and the reference cell use a same receive link at the user equipment, carrier frequencies of the Scell and the reference cell, a difference in path loss between the Scell and the reference cell, frequency band(s) in which the Scell and the reference cell are located, capability information of the user equipment, and grouping information of the Scell. According to the method shown in FIG. 6, the network device may receive the capability information reported by the user equipment, and when the SSB configuration and the SMTC are not performed for the SCell of the user equipment based on the capability information, excessive time and frequency resources due to the SSB configuration and the SMTC are effectively avoided, which brings about a better effect of energy saving in the network.

[0167] Optionally, the method shown in FIG. 6 may further include: transmitting to the user equipment information indicating a reference cell. According to embodiments, the reference cell may be determined from among serving cells of the user equipment based on the information indicating the reference cell, wherein the serving cells includes a primary cell or a special cell and an activated secondary cell that carries a SSB.

[0168] Optionally, the method shown in FIG. 6 may further include: determining a reference cell based on a first rule. For example, the first rule may include at least one of: determining the reference cell based on frequency separation(s) between the secondary cell and the serving cells; determining the reference cell based on relative frequency separation(s) between the secondary cell and the serving cells; and determining the reference cell based on signal quality / power of the serving cells. Details of determining the reference cell may be found in the description above and will not be repeated here.

[0169] Optionally, the grouping information may be configured by the network node or determined according to at least one of: the frequency separation between the secondary cell and the reference cell, the relative frequency separation between the secondary cell and the reference cell, whether or not the secondary cell and the reference cell use the same RF unit module in the network node, whether or not the secondary cell and the reference cell use the same receive link at the user equipment, the carrier frequencies of the secondary cell and the reference cell, the difference in the path loss between the secondary cell and the reference cell, and the frequency band(s) in which the secondary cell and the reference cell are located.

[0170] For example, the method shown in FIG. 6 may further include: transmitting second information to the user equipment, wherein the second information is used for the user equipment to obtain the grouping information. According to embodiments, the activation or de-activation delay requirement may include at least one of: a requirement regarding a receive timing difference of the secondary cell from the reference cell; a requirement regarding a difference of the reception power between the secondary cell and the reference cell; a requirement regarding a type of quasi-co-location relationship between a reference signal and a tracking reference signal of the secondary cell, and a requirement regarding a type of quasi-co-location relationship between a tracking reference signal of the secondary cell and a SSB of the reference cell, but not limited thereto. Additionally, optionally, according to embodiments, the time alignment error of the network node may be associated with at least one of: the frequency separation between the secondary cell and the reference cell, the relative frequency separation between the secondary cell and the reference cell, whether or not the secondary cell and the reference cell uses the same RF unit module in the network node, the carrier frequencies of the secondary cell and the reference cell, the difference in the path loss between the secondary cell and the reference cell, the frequency band(s) in which the secondary cell and the reference cell are located.

[0171] In the description with reference to FIG. 4, the grouping-related contents have been described and will not be repeated here, and the relevant details may be found in the description above.

[0172] The method performed by a user equipment and the method performed by a network node involved in the idea of the present disclosure have been described above with reference to FIGS. 4 to 6, and it is helpful to the energy saving of the network according to the above methods.

[0173] FIG. 7 is a schematic diagram illustrating an example of communication between a user equipment and a network node according to embodiments of the present disclosure.

[0174] In order to facilitate a more intuitive understanding of the idea of the present disclosure, below, an example of the communication between the user equipment and the network node is briefly described with reference to FIG. 7. However, it should be understood that FIG. 7 is only an example and does not indicate that the communication between the user equipment and the network node may only be performed with the process shown in FIG. 7.

[0175] As shown in FIG. 7, firstly, the user equipment may report capability information as described above to the network node (e.g., a base station device). Subsequently, the network node may instruct to add / modify / release the SCell through a Radio Resource Control (RRC) reconfiguration message. With the RRC reconfiguration message, the user equipment knows which SCell or SCells need to be added / modified / released, and upon completion of the addition / modification / release, the user equipment may transmit an RRC reconfiguration completion response to the network node. Next, the network node may transmit first information and second information to the user equipment. The first information may be used to determine that the user equipment determines a reference cell for the SCell, and the second information may be used to obtain grouping information, and the grouping information may be used to determine an activation or de-activation delay requirement to be satisfied by the user equipment to perform the activation or de-activation of the SCell when the SCell has no SSB configuration and has no SMTC. In addition, the network node may transmit a Media Access Control-Control Element (MAC-CE) message to the user equipment to tell the user equipment which SCell or SCells to be activated or de-activated. Finally, the user equipment performs the activation or de-activation for the SCell(s) in the case that the activation or de-activation delay requirement is satisfied.

[0176] It is noted that although the first information, the second information and the MAC-CE are shown as being transmitted in sequence in FIG. 7, there is no fixed sequence in which the first information, the second information and the MAC-CE message are transmitted, and it is possible to transmit the first information and the second information prior to the MAC-CE message, as well as to transmit the first information and the second information after the MAC-CE message. In addition, there is no fixed sequence for transmitting the first information and the second information, either the first information may be transmitted at first, followed by the second information, or the second information may be transmitted at first, followed by the first information, or the first information and the second information may be transmitted together.

[0177] FIG. 8 is a block diagram illustrating a user equipment according to embodiments of the present disclosure. Referring to FIG. 8, the user equipment 800 may include a transceiver 801 and a processor 802, wherein the processor 802 is coupled to the transceiver 801 and configured to perform the method performed by the user equipment described above.

[0178] By way of example, the user equipment may be a PC computer, a tablet device, a personal digital assistant, a smartphone, or other device capable of executing the above set of instructions. In addition, the user equipment does not have to be a single user equipment, but may also be any collection of devices or circuits capable of executing instructions (or sets of instructions) individually or jointly. The user equipment may also be part of an integrated control system or system manager, or may be any portable electronic device.

[0179] In a user equipment, a processor may 802 may include a central processing unit (CPU), a graphics processing unit (GPU), a programmable logic device, a dedicated processor system, a microcontroller, or a microprocessor, among others. By way of example and not limitation, the processor may also include an analog processor, a digital processor, a microprocessor, a multi-core processor, a processor array, and the like.

[0180] FIG. 9 is a block diagram illustrating a network node according to embodiments of the present disclosure. Referring to FIG. 9, the network node 900 may include a transceiver 901 and a processor 902, wherein the processor 902 is coupled to the transceiver 901 and configured to perform the method performed by a network node described above. As an example, the network node may be any network entity (e.g., a base station device, a sidelink device, etc.), or a network functional entity.

[0181] In addition, according to an embodiment of the present disclosure, a computer readable storage medium storing instructions is also provided. The instructions, when executed by at least one processor, causes the at least one processor to perform any of the above methods as described above. Examples of computer-readable storage media herein include: Read Only Memory (ROM), Random Access Programmable Read Only Memory (RAPROM), Electrically Erasable Programmable Read Only Memory (EEPROM), Random Access Memory (RAM), Dynamic Random Access Memory (DRAM), Static Random Access Memory (SRAM), flash memory, non-volatile memory, CD-ROM, CD-R, CD+R, CD-RW, CD+RW, DVD-ROM, DVD-R, DVD+R, DVD-RW, DVD+RW, DVD-RAM, BD-ROM, BD-R, BD-R LTH, BD-RE, Blue-ray or optical disk storage, Hard Disk Drive (HDD), Solid State Drive (SSD), card storage (such as multimedia cards, secure digital (SD) cards or extremely fast digital (XD) cards), magnetic tapes, floppy disks, magneto-optical data storage devices, optical data storage devices, hard disks, solid state disks, and any other devices that are configured to store computer programs and any associated data, data files and data structures in a non-transitory manner and provide the computer programs and any associated data, data files and data structures to a processor or computer so that the processor or computer can execute the computer programs. The instructions or computer programs in the computer-readable storage medium described above may be executed in an environment deployed in a computer device, such as client, host, proxy device, server, etc. In addition, in one example, the computer programs and any associated data, data files, and data structures are distributed on a networked computer system, so that the computer programs and any associated data, data files, and data structures are stored, accessed and executed through one or more processors or computers in a distributed manner.

[0182] Other embodiments of the present disclosure will readily be conceived by those skill in the art after considering the specification and practicing the invention disclosed herein. The present disclosure is intended to cover any variation, use, or adaptation of the present disclosure that follows the general principle of the present disclosure and includes commonly known or customary technical means in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of the disclosure is limited by the claims.

Claims

1.A method performed by a terminal in a wireless communication system, the method comprising:receiving, from a base station, information on a secondary cell (SCell) activation command; andin case that condition is met and the terminal is not provided with synchronization signal block (SSB) configuration nor SSB based measurement timing configuration (SMTC) for the SCell, activating the SCell within an activation time,wherein the terminal supports SCell without the SSB for inter band carrier aggregation (CA), andwherein the condition comprises at least one of information on a receiving timing difference (RTD) between the SCell and a reference cell, information on power difference of a symbol between the SCell and the reference cell, or information on a quasi co-location (QCL) associated with a reference signal (RS).2.The method of claim 1, further comprising:transmitting, to the base station, information indicating whether the terminal supports the SCell without the SSB for the inter-band CA.3.The method of claim 1, further comprising:receiving, from the base station, information on the reference cell.4.The method of claim 1,wherein the SCell belongs to frequency range 1 (FR1),wherein the reference cell is on different FR1 band from the SCell, andwherein the activation time is an activation delay Tactivation_time.5.A method performed by a base station in a wireless communication system, the method comprising:transmitting, to a terminal, information on a secondary cell (SCell) activation command,wherein, in case that condition is met and the terminal is not provided with synchronization signal block (SSB) configuration nor SSB based measurement timing configuration (SMTC) for the SCell, the SCell is activated within an activation time,wherein the terminal supports SCell without the SSB for inter band carrier aggregation (CA), andwherein the condition comprises at least one of information on a receiving timing difference (RTD) between the SCell and a reference cell, information on power difference of a symbol between the SCell and the reference cell, or information on a quasi co-location (QCL) associated with a reference signal (RS).6.The method of claim 5, further comprising:receiving, from the terminal, information indicating whether the terminal supports the SCell without the SSB for the inter-band CA; andtransmitting, to the terminal, information on the reference cell.7.The method of claim 5,wherein the SCell belongs to frequency range 1 (FR1),wherein the reference cell is on different FR1 band from the SCell, andwherein the activation time is an activation delay Tactivation_time.8.A terminal in a wireless communication system, the terminal comprising:a transceiver; andat least one processor coupled with the transceiver and configured to:receive, from a base station, information on a secondary cell (SCell) activation command, andin case that condition is met and the terminal is not provided with synchronization signal block (SSB) configuration nor SSB based measurement timing configuration (SMTC) for the SCell, activate the SCell within an activation time,wherein the terminal supports SCell without the SSB for inter band carrier aggregation (CA), andwherein the condition comprises at least one of information on a receiving timing difference (RTD) between the SCell and a reference cell, information on power difference of a symbol between the SCell and the reference cell, or information on a quasi co-location (QCL) associated with a reference signal (RS).9.The terminal of claim 8, wherein the at least one processor is configured to:transmit, to the base station, information indicating whether the terminal supports the SCell without the SSB for the inter-band CA.10.The terminal of claim 8, wherein the at least one processor is configured to:receive, from the base station, information on the reference cell.11.The terminal of claim 8,wherein the SCell belongs to frequency range 1 (FR1),wherein the reference cell is on different FR1 band from the SCell, andwherein the activation time is an activation delay Tactivation_time.12.A base station in a wireless communication system, the base station comprising:a transceiver; andat least one processor coupled with the transceiver and configured to:transmit, to a terminal, information on a secondary cell (SCell) activation command,wherein, in case that condition is met and the terminal is not provided with synchronization signal block (SSB) configuration nor SSB based measurement timing configuration (SMTC) for the SCell, the SCell is activated within an activation time,wherein the terminal supports SCell without the SSB for inter band carrier aggregation (CA), andwherein the condition comprises at least one of information on a receiving timing difference (RTD) between the SCell and a reference cell, information on power difference of a symbol between the SCell and the reference cell, or information on a quasi co-location (QCL) associated with a reference signal (RS).13.The base station of claim 12, wherein the at least one processor is configured to:receive, from the terminal, information indicating whether the terminal supports the SCell without the SSB for the inter-band CA.14.The base station of claim 12, wherein the at least one processor is configured to:transmit, to the terminal, information on the reference cell.15.The base station of claim 12,wherein the SCell belongs to frequency range 1 (FR1),wherein the reference cell is on different FR1 band from the SCell, andwherein the activation time is an activation delay Tactivation_time.

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