WO2025033757A1

WO2025033757A1 - Ue, network node and methods thereof and storage medium

Info

Publication number: WO2025033757A1
Application number: PCT/KR2024/010351
Authority: WO
Inventors: Lili Wang; Yanze FU; Haijie QIU; Min Wu
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2023-08-09
Filing date: 2024-07-18
Publication date: 2025-02-13
Anticipated expiration: 2026-02-09
Also published as: CN119483848A

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. The present disclosure provides a UE, a network node, methods thereof and a storage medium. A method performed by a user equipment in a wireless communication system, including: receiving information indicating a timing difference between a reference cell and a secondary cell transmitted by a network node; and performing uplink transmission on the secondary cell, wherein a transmission time of an uplink frame is related to the timing difference and an uplink transmission timing advance of the reference cell in a case that the secondary cell does not have a downlink signal.

Description

UE, NETWORK NODE AND METHODS THEREOF AND STORAGE MEDIUM

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.

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 (THz) 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.

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.

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.

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.

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.

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.

In order to meet the increasing requirement 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".

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.

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.

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.

The present disclosure relates to controlling a plurality of reference signal ports.

According to a first aspect of the embodiments of the present disclosure, there is provided a method performed by a user equipment in a wireless communication system, the method includes: receiving information indicating a timing difference between a reference cell and a secondary cell transmitted by a network node; and performing uplink transmission on the secondary cell, wherein a transmission time of an uplink frame is related to the timing difference and an uplink transmission timing advance of the reference cell in a case that the secondary cell does not have a downlink signal.

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.

Aspects of the present disclosure provide efficient communication methods in a wireless communication system.

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.

FIGURE 1 illustrates an example wireless network 100 according to various embodiments of the present disclosure;

FIGURE 2a and 2b illustrate an example wireless transmission path and an example wireless reception path according to the present disclosure;

FIGURE 3a illustrates an example UE 116 according to the present disclosure;

FIGURE 3b illustrates an example gNB 102 according to the present disclosure;

FIGURE 4 illustrates a flowchart illustrating a method performed by a user equipment according to embodiments of the present disclosure;

FIGURE 5 illustrates a flowchart illustrating a first example of a method performed by a user equipment according to an embodiment of the present disclosure;

FIGURE 6 illustrates a flowchart illustrating a second example of a method performed by a user equipment according to an embodiment of the present disclosure;

FIGURE 7 illustrates a flowchart illustrating a method performed by a network node according to embodiments of the present disclosure;

FIGURE 8 illustrates a schematic diagram illustrating a first example of communication between a user equipment and a network node according to embodiments of the present disclosure;

FIGURE 9 illustrates a schematic diagram illustrating a second example of communication between a user equipment and a network node according to embodiments of the present disclosure;

FIGURE 10 illustrates a schematic diagram illustrating a third example of communication between a user equipment and a network node according to embodiments of the present disclosure;

FIGURE 11 illustrates a block diagram illustrating a user equipment according to embodiments of the present disclosure;

FIGURE 12 illustrates a block diagram illustrating a network node according to embodiments of the present disclosure;

FIGURE 13 illustrates a block diagram illustrating a structure of a UE according to various embodiments of the present disclosure; and

FIGURE 14 illustrates a block diagram illustrating a structure of a base station according to various embodiments of the present disclosure, as disclosed herein.

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.

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.

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.

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.

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.

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.

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.

FIGURE 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.

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.

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).

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.

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.

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.

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.

FIGUREs 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.

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.

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.

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.

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.

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.

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.).

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.

FIGURE 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.

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.

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).

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.

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.

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.

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).

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 FIGURE 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.

FIGURE 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.

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.

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.

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.

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.

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.

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.

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.

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.

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).

With the contiguous 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 a wireless network, in order to support a wider transmission bandwidth for the purpose of increasing　throughput 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 contiguous, which is called intra-band contiguous CA; that multiple component carriers are in the same frequency band and there is a certain separation 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).

The energy consumed by a network device for uplink reception is only 0.2 to 0.5 of the energy consumed for downlink transmission. Therefore, for scenarios that require more uplink services, such as remote driving, machine vision, and factory video surveillance, network energy saving may be achieved by turning off downlink transmission for the SCell and using only uplink transmission for the SCell. How to ensure that uplink transmission may be performed correctly while saving energy in the network is a matter of concern. The present disclosure proposes an idea to ensure that uplink transmission may be performed correctly while saving energy in the network. Specifically, according to the idea 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. The idea of the present disclosure may be applied at least in a carrier aggregation scenario to achieve network energy saving while ensuring that uplink transmission may be performed correctly.

In the following, the idea of the present disclosure will be described in detail with reference to FIGS. 4 through 14.

FIGURE 4 illustrates a flowchart illustrating a method performed by a user equipment according to embodiments of the present disclosure.

Referring to FIG. 4, at step S410, information indicating a timing difference between a reference cell and a Scell transmitted by a network node is received. As an example, the user equipment may receive first information transmitted by the network node, wherein the first information may include the information indicating the timing difference between the reference cell and the Scell.

According to embodiments, the reference cell is determined based on information for indicating the reference cell received from the network node; or the reference cell is determined from among serving cells of the user equipment based on at least one of frequency separations between the Scell and the serving cells, relative frequency separations between the Scell and the serving cells and signal strength/quality/power of the serving cells, wherein the serving cells include a primary cell or a special cell and an activated Scell that carries a synchronization signal/physical broadcast channel block (SS/PBCH block, SSB).

In the present disclosure, the information for indicating the reference cell may be referred to as "second information". For example, there may be three options for how to select the reference cell:

In a first option, the user equipment determines the reference cell based on the second information received from the network node. For example, the user equipment may obtain from the network node, by using the second information, which activated cell is a reference cell for the SCell that does not carry a downlink signal.

In a second option, the reference cell is determined from among serving cells of the user equipment based on at least one of frequency separations between the Scell and the serving cells, relative frequency separations between the Scell and the serving cells and signal strength/quality/power of the serving cells, wherein the serving cells include a primary cell or a special cell and an activated Scell that carries a synchronization signal/physical broadcast channel block (SS/PBCH block, SSB). In the following, the determining of the reference cell from the serving cells based on at least one of the above information is also referred to as determining the reference cell based on a first rule. For example, the determining of the reference cell based on the frequency separations between the Scell and the serving cells of the user equipment 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, the determining of the reference cell based on the relative frequency separations between the Scell and the serving cells 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, the determining of the reference cell based on the signal strength/quality/power of the serving cells may include: selecting a serving cell with the greatest signal strength/quality/power as the reference cell, or selecting a serving cell with the signal strength/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 the SCell that does not carry a downlink signal among activated cells of a current cell group based on at least one of the above information. For example, an activated cell having the smallest carrier frequency separation and/or relative frequency separation in the same cell group as the SCell not carrying a downlink signal is selected as the reference cell, or the reference cell may be selected in accordance with a principle of a maximum signal strength/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 a requirement of the predefined threshold is the reference cell.

In a third option, the user equipment determines the reference cell based on the second information and at least one of the frequency separations between the Scell and the serving cells of the user equipment, the relative frequency separations between the Scell and the serving cells and the signal strength/quality/power of the serving cells. For example, the user equipment first determines a reference cell from the network node by means of the second information, and then the user equipment may change the reference cell in accordance with changes in activated cells in a cell group and based on at least one of the frequency separations between the Scell and the serving cells of the user equipment, the relative frequency separations between the Scell and the serving cells and the signal strength/quality/power of the serving cells.

The reference cell may provide, for a Scell that does not carry a downlink signal, a reference for correct execution of activation and de-activation of the Scell and uplink transmission on the Scell. For example, information of the reference cell may include uplink timing synchronization information and/or uplink power control information of the reference cell. The user equipment may provide, for the SCell that does not carry a downlink signal, the reference for uplink timing synchronization and/or uplink power control information by using the information of the reference cell, to perform the activation, the de-activation of the Scell that does not carry a downlink signal and/or the uplink transmission on the Scell. Optionally, in addition to providing the reference for the correct execution of the activation, the de-activation of the Scell that does not carry a downlink signal and the uplink transmission on the Scell by means of the information of the reference cell, it is also possible to further perform the activation, the de-activation of the Scell and the uplink transmission on the Scell in conjunction with first information transmitted from the network node on the basis of the information of the reference cell. Alternatively, it is also possible to perform the activation and de-activation and/or uplink transmission on the Scell using only the first information.

According to embodiments, the first information may include at least one of information indicating a timing difference between the Scell and the reference cell and/or information indicating a power difference between the Scell and the reference cell; timing difference information and/or power difference information of the Scell. For example, if the first information includes the information indicating the timing difference between the Scell and the reference cell and/or the information indicating the power difference between the Scell and the reference cell, the activation, the de-activation of the Scell and/or the uplink transmission on the Scell may be performed using the information of the reference cell together with the first information. For another example, if the first information includes the timing difference information and/or the power difference information of the Scell, the activation, the de-activation of the Scell and/or the uplink transmission on the Scell may be performed using only the first information.

As an example, the first information may be RRC or MAC-CE or DCI signaling.

At step 420, uplink transmission is performed on the Scell. According to embodiments, a transmission time of an uplink frame is related to the timing difference and an uplink transmission timing advance of the reference cell in a case that the Scell does not have a downlink signal.

According to the method performed by the user equipment according to embodiments of the present disclosure, since the user equipment receives the information indicating the timing difference between the reference cell and the Scell from the network node, and the transmission time of the uplink frame is related to the timing difference and the uplink transmission timing advance of the reference cell in the case that the Scell does not have a downlink signal, it is possible to ensure that the uplink transmission may be performed correctly while saving energy in the network.

Alternatively, the method shown in FIG. 4 may further include: reporting capability information to the 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. According to embodiments, the capability information is used to indicate that the user equipment supports that a SCell does not carry a downlink signal. According to embodiments, the SCell may be a cell other than a PCell or SpCell in a cell group consisting of multiple cells joined together by a carrier aggregation (CA) technology. For example, 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 downlink signal in any carrier aggregation scenario, wherein the carrier aggregation scenario includes an intra-band carrier aggregation scenario and an inter-band carrier aggregation scenario; second capability information indicating that the user equipment only supports that the Scell does not carry a downlink signal in an intra-band contiguous carrier aggregation scenario; third capability information indicating that the user equipment only supports that the Scell does not carry a downlink signal in the intra-band carrier aggregation scenario, wherein the intra-band carrier aggregation scenario includes an intra-band contiguous carrier aggregation scenario and an intra-band non-contiguous carrier aggregation scenario; fourth capability information indicating that the user equipment only supports that the Scell does not carry a downlink signal in the inter-band carrier aggregation scenario; fifth 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 downlink signal. Here, if the user equipment reports the fifth 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 a first condition does not carry a downlink signal, and the user equipment supporting that the Scell whose frequency separation and/or relative frequency separation with the reference cell satisfies the first condition does not carry a downlink signal may implicitly indicates that the user equipment supports that the Scell does not carry a downlink signal in a carrier aggregation scenario. Here, the frequency separation and/or relative frequency separation with the reference cell, and the first condition may be predefined.

For example, the frequency separation with 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 limit of the SCell CC and a lower frequency limit 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 limit of the SCell CC and an upper frequency limit of the reference cell CC, a difference between a lower frequency limit of the SCell CC and the lower frequency limit of the reference cell CC, and a difference between the lower frequency limit of the SCell CC and the upper frequency limit 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 limit of a CC with the highest frequency and a lower frequency limit 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 limit of the CC with the highest frequency and an upper frequency limit of the CC with the lowest frequency in the same frequency band, a difference between a lower frequency limit of the CC with the highest frequency and the lower frequency limit of the CC with the lowest frequency in the same frequency band, and a difference between the lower frequency limit of the CC with the highest frequency and the upper frequency limit 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 separations 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 limit of a CC with the highest frequency in a frequency band with the highest frequency and a lower frequency limit 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 limit of the CC with the highest frequency in the frequency band with the highest frequency and an upper frequency limit of the CC with the lowest frequency in the frequency band with the lowest frequency, a difference between a lower frequency limit of the CC with the highest frequency in the frequency band with the highest frequency and the lower frequency limit of the CC with the lowest frequency in the frequency band with the lowest frequency, a difference between the lower frequency limit of the CC with the highest frequency in the frequency band with the highest frequency and the lower frequency limit of the CC with the lowest frequency in the frequency band with the lowest frequency, but not limited to thereto.

For example, the relative frequency separation with 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 limit or a center frequency or a lower frequency limit of a CC of the SCell, dividing the frequency separation between the SCell and the reference cell by an upper frequency limit or a center frequency or a lower frequency limit of a CC of the reference cell, dividing the frequency separation between the SCell and the reference cell by an upper frequency limit or a center frequency or a lower frequency limit 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 limit or a center frequency or a lower frequency limit of a CC with the highest or lowest frequency in the frequency band in which the reference cell is located, but not limited thereto.

For example, the first condition may include at least one of the frequency separation between the SCell that does not carry a downlink signal and the reference cell being within a certain range, the relative frequency separation being within a certain ratio range, but not limited to thereto.

According to embodiments, the capability information is reported per a component carrier (CC), or per a combination of multiple CCs, or per a user equipment. If the capability information is reported per the CC, it indicates that the user equipment supports that the Scell does not carry a downlink signal on that component carrier. If the capability information is reported per the combination of CCs, it indicates that the user equipment supports that the Scell does not carry a downlink signal on that combination of CCs. If the capability information is reported per the user equipment, it indicates that the user equipment supports that the Scell does not carry a downlink signal on any CC and any combination of CCs.

According to embodiments, the network node may not transmit a downlink signal to the Scell based on the capability information. According to embodiments, in the case that the Scell does not have a downlink signal, there are three options for determining the uplink timing synchronization information of the Scell as follows:

Option 1: determining the uplink timing synchronization information of the Scell based on the uplink timing synchronization information of the reference cell. For example, the uplink timing synchronization information of the reference cell may include an uplink timing advance N_TA information of the reference cell and a fixed timing advance difference N_{TA_offset} of the Scell. In this case, the uplink timing synchronization information of the SCell that does not carry a downlink signal may be determined directly based on the uplink timing advance N_TA information of the reference cell in combination with the fixed timing advance difference N_{TA_offset} of the Scell. For example, the uplink timing advance N_TA of the reference cell is directly used as the uplink timing advance of the SCell that does not carry a downlink signal and the fixed timing advance difference N_{TA_offset} of the Scell is used as the fixed timing advance difference of the SCell that does not carry a downlink signal, and then the uplink timing synchronization information of the SCell that does not carry a downlink signal is determined based on the determined uplink timing advance and the fixed timing advance difference of the SCell that does not carry a downlink signal.

Option 2: determining the uplink timing synchronization information of the Scell based on the uplink timing synchronization information of the reference cell and information included in the first information regarding the timing difference between the Scell and the reference cell. For example, the uplink timing synchronization information of the SCell that does not carry a downlink signal may be determined based on the uplink timing advance N_TA information of the reference cell in combination with the fixed timing advance difference N_{TA_offset} of the Scell, together with the timing difference deltaT included in the first information, wherein deltaT describes the timing difference between the Scell that does not carry a downlink signal and the reference cell.

Option 3: determining the uplink timing synchronization information of the Scell based on timing difference information regarding the Scell included in the first information. In Option 3, the network node may directly indicate by the first information the timing difference information required for determining the uplink timing synchronization information of the Scell.

Whether to adopt Option 1, Option 2 or Option 3 may depend on whether there is the first information, or what is included in the first information. If the user equipment does not receive the first information from the network node, the uplink timing synchronization information of the Scell that does not carry a downlink signal may be determined based on the uplink timing synchronization information of the reference cell. If the user equipment receives the first information from the network node and the first information includes information regarding the timing difference between the Scell that does not carry a downlink signal and the reference cell, the uplink timing synchronization information of the Scell may be determined based on the uplink timing synchronization information of the reference cell and the first information. If the user equipment receives the first information from the network node and the first information includes the timing difference information regarding the Scell that does not carry a downlink signal, the uplink timing synchronization information of the Scell may be determined based on the first information without the information of the reference cell.

The transmission time of the uplink frame belongs to one of the uplink timing synchronization information, and according to the above Option 2, in the case that the Scell does not have a downlink signal, the transmission time of the uplink frame may be related to the uplink transmission timing advance of the reference cell and the timing difference between the reference cell and the Scell.

According to embodiments, the transmission time of the uplink frame being related to the timing difference and the uplink transmission timing advance of the reference cell includes: the transmission time of the uplink frame satisfies a requirement that the uplink frame transmission takes place before the reception of the first detected path (in time) of the corresponding downlink frame from the reference cell, the time is related to the timing difference and the uplink transmission timing advance of the reference cell.

For example, when the uplink transmission is performed on the Scell, the transmission time of the uplink frame shall satisfy the following requirement: if the user equipment has a capability to support that the SCell does not carry a downlink signal as indicated by any of the aforementioned capability information, the uplink frame transmission takes place before the reception of the first detected path (in time) of the corresponding downlink frame from the reference cell, e.g., the time is (N_TA+N_{TA_offset})×T_c, in this case, the user equipment uses the uplink transmission timing advance N_TA of the reference cell as the uplink reference transmission timing advance of the Scell; for example, the time is (N_TA+N_{TA_offset})+deltaT)×T_c, in this case, the user equipment uses the uplink transmission timing advance N_TA of the reference cell as the uplink reference transmission timing advance of the Scell and uses the timing difference deltaT indicated in the above first information; for another example, the time is (N_{TA_NEW}+N_{TA_offset})×T_c, in this case, the user equipment uses the timing difference information of the Scell (indicated as N_{TA_NEW})) in the above first information as the uplink transmission timing advance of the Scell. Wherein N_{TA_offset} is the fixed timing advance difference of the Scell and T_c is the basic unit of time.

According to embodiments, when the uplink transmission is performed on the Scell at step S420, uplink timing requirement(s) with respect to the Scell may include at least one of: an initial transmission timing control requirement of the user equipment; and a minimum transmission timing error requirement that the Scell should satisfy, but not limited to thereto.

Optionally, the method shown in FIG. 4 may further include: determining a reference point for an initial transmission timing control requirement, wherein the reference point is determined based on a downlink timing of the reference cell, the timing difference, and the uplink transmission timing advance of the reference cell. According to embodiments, the downlink timing of the reference cell may be a first time corresponding to a time of reception of a first path on a time domain of a downlink frame, and the first time is received from the reference cell at an antenna of the user equipment for determining the downlink timing by the user equipment. For example, if the user equipment has a capability to support that the SCell does not carry a downlink signal as indicated by any of the foregoing capability information, the user equipment may, for example, after obtaining the information of the reference cell, use the uplink transmission timing advance N_TA of the reference cell as the uplink reference transmission timing advance of the SCell that does not carry a downlink signal, use the fixed timing advance difference N_{TA_offset} of the Scell as a reference fixed timing advance difference of the SCell that does not carry a downlink signal, and may further use the timing difference deltaT indicated in the first information if there is the first information, to determine the reference point for the initial transmission timing control requirement of the user equipment for the SCell that does not carry a downlink signal. For example, if the user equipment receives the first information from the network node and the first information includes the timing difference deltaT, the reference point may be the downlink timing of the reference cell minus (N_TA+N_{TA_offset}+deltaT)×T_c, wherein T_c is the basic unit of time, the downlink timing is defined as the first time which is a receiving time of a first path on a time domain of a corresponding downlink frame, and the first time is received from the reference cell at an antenna of the user equipment for determining the downlink timing by the user equipment. And if the user equipment does not receive the first information, delatT=0 in the above (N_TA+N_{TA_offset}+deltaT). For another example, if the user equipment receives the first information from the network node and the first information includes timing difference information (denoted as N_{TA_NEW}) of the SCell that does not carry a downlink signal, the reference point may be determined by using the timing difference N_{TA_NEW} of the SCell that does not carry a downlink signal and the fixed timing advance difference N_{TA_offset} of the SCell that does not carry a downlink signal, e.g., the reference point may be the downlink timing of the reference cell minus (N_{TA_NEW}+N_{TA_offset})×T_c. For another example, when the user equipment does not obtain reference cell information of the SCell that does not carry a downlink signal or there is no reference cell that satisfies a reference cell selection threshold requirement, a PCell or a SpCell may be used as the reference cell.

According to embodiments, the Scell should satisfy a minimum transmission timing error requirement to ensure that a transmission timing error between the Scell and a reference timing does not exceed a timing error limit value, wherein the reference timing is a second time before a downlink timing of the reference cell, the second time being determined based on the timing difference and the uplink transmission timing advance of the reference cell. For example, the SCell should satisfy the minimum transmission timing error requirement to ensure that the transmission timing error between the SCell and the reference timing does not exceed ±T_e, and when the transmission timing error between the SCell and the reference timing exceeds ±T_e, it should be adjusted to be within ±T_e, and then the user equipment may transmit an uplink signal on the SCell, wherein T_e is a timing error limit value. The reference timing is the second time before the downlink timing of the reference cell, for example, the second time is (N_TA+N_{TA_offset})×T_c, in this case, the user equipment uses the uplink transmission timing advance N_TA of the reference cell as the uplink reference transmission timing advance of the Scell; for example, the second time is (N_TA+N_{TA_offset}+deltaT)×T_c, in this case, the user equipment uses the uplink transmission timing advance N_TA of the reference cell as the uplink reference transmission timing advance of the Scell, and uses the timing difference deltaT indicated in the above first information; and for another example, the second time is (N_{TA_NEW}+N_{TA_offset})×T_c, in this case, the user equipment uses the timing difference information (denoted as N_{TA_NEW}) of the Scell in the above first information as the uplink transmission timing advance of the Scell. Wherein N_{TA_offset} is the fixed timing advance difference of the Scell and T_c is the basic unit of time.

Optionally, the method described in FIG. 4 may further include: determining uplink power control information of the Scell according to uplink power control information of the reference cell and a power difference between the Scell and the reference cell configured by the network node. For example, the network node may configure the power difference between the Scell and the reference cell by means of the first information mentioned above. As mentioned above, the first information may include at least one of information indicating a timing difference between the Scell and the reference cell and/or information indicating a power difference between the Scell and the reference cell; timing difference information and/or the power difference information of the Scell.

Determining the uplink power control information of the Scell according to uplink power control information of the reference cell and the power difference between the Scell and the reference cell configured by the network node is one option for determining the uplink power control information of the Scell. However, the method of determining the uplink power control information of the Scell is not limited to this option, but optionally may be other options.

For example, according to embodiments of the present disclosure, determining the uplink power control information of the Scell may have the following three schemes:

Option 1: determining the uplink power control information of the Scell based on the uplink power control information of the reference cell. For example, the uplink power control information of the SCell that does not carry a downlink signal may be determined by: using the uplink power control information of the reference cell, and calculating a path loss difference between the SCell that does not carry a downlink signal and the reference cell through respective carrier frequencies of the reference cell and the SCell that does not carry a downlink signal, optionally adjusting a path loss compensation factor, and ultimately based on the uplink power control information of the reference cell and the path loss difference and/or the adjusted path loss compensation factor.

Option 2: determining the uplink power control information of the Scell based on the uplink power control information of the reference cell and the information regarding the power difference between the Scell and the reference cell included in the first information. For example, the uplink power control information of the Scell that does not carry a downlink signal may be determined by using the uplink power control information of the reference cell in combination with the power difference deltaP indicated in the first information, wherein deltaP describes the difference of the uplink path loss of the SCell that does not carry a downlink signal between the reference cell as estimated from the network device.

Option 3: determining the uplink power control information of the Scell based on the information regarding the power difference of the Scell included in the first information. In Option 3, the network node may directly indicate, by the first information, the power difference information of the Scell required for determining the uplink power control information of the Scell.

Whether to adopt Option 1, Option 2 or Option 3 may depend on whether there is the first information, or the information content included in the first information. If the user equipment does not receive the first information from the network node, the uplink power control information of the Scell that does not carry a downlink signal may be determined based on the uplink power control information of the reference cell. If the user equipment receives the first information from the network node and the first information includes the information regarding the power difference between the Scell that does not carry a downlink signal and the reference cell, the uplink power control information of the Scell may be determined based on the uplink power control information of the reference cell and the first information. If the user equipment receives the first information from the network node and the first information includes the information regarding the power difference of the Scell that does not carry a downlink signal, the uplink power control information of the Scell may be determined based on the first information without using the information of the reference cell.

Optionally, according to embodiments, the activation, the de-activation of the Scell and/or the uplink transmission on the Scell may be performed based on the uplink timing synchronization information and/or uplink power control information of the Scell, when the uplink timing synchronization information and/or uplink power control information of the Scell is determined.

Optionally, the present disclosure further proposes that the activation and/or the de-activation of the Scell that does not carry a downlink signal may be initiated by the user equipment, thereby solving the problem that the network device has no way of determining when it should initiate the activation and/or the de-activation of the SCell that does not carry a downlink signal. For example, there may be two options for initiating activation and/or de-activation of the Scell that does not carry a downlink signal by the user equipment. One option is that the user equipment first notifies the network node that the Scell that does not carry a downlink signal needs to be activated and/or de-activated, and then activates and/or de-activates the Scell based on signaling received from the network node for notifying it to activate and/or de-activate the Scell. Another option is that the user equipment directly informs the network node that the user equipment will activate and/or de-activate the Scell that does not carry a downlink signal at a predetermined time, in which case the user equipment does not need to receive from the network node the signaling for informing it to activate and/or de-activate the Scell so as to activate and/or de-activate the Scell.

In order to realize both of the above options, although not shown, optionally, the method shown in FIG. 4 may further include: transmitting, to the network node, a notification that the Scell needs to be activated or de-activated, receiving a command for activating or de-activating the Scell transmitted by the network node, and activating or de-activating the Scell according to the command; or transmitting, to the network node, a notification for activating or de-activating the Scell, activating or de-activating the Scell at a predetermined time, information of the predetermined time being included in the notification or is a predefined value or a value configured by a network high layer.

For example, the user equipment may transmit third information to the network node and receive signaling from the network node for activating or de-activating the Scell, wherein the third information is used to notify the network node that the Scell needs to be activated or de-activated. Alternatively, the user equipment may transmit the third information to the network node, wherein the third information is used to notify activation or de-activation of the Scell, and wherein the third information includes information about a predetermined time at which the Scell is activated or de-activated, and subsequently, the user equipment may activate or de-activate the Scell at the predetermined time. Alternatively, the user equipment may transmit the third information to the network node, wherein the third information is used to notify activation or de-activation of the Scell, and subsequently, the user equipment may activate or de-activate the Scell at a time which is a predefined value or a value configured by a network high layer. As an example, the third information may be Radio Resource Control (RRC) information or Media Access Control-Control Element (MAC-CE)information.

For example, the user equipment determines, based on a situation of a uplink data service, that when additional SCell(s) is/are required to share the uplink data service, the user equipment may notify the network device via a PCell or a SpCell or a reference cell using the third information that the SCell that do not carry a downlink signal needs to be activated, and then the network device may notify, via MAC-CE signaling, the user equipment to activate the SCell that does not carry a downlink signal. For another example, the user equipment determines, based on the situation of the uplink data service, that when the additional SCell(s) is/are required to share the uplink data service, the user equipment may notify the network device via the PCell or the SpCell or the reference cell using the third information that the SCell that does not carry a downlink signal will be activated in the n+ kth time slot, where n is a current time slot, k may be a predefined value or a value configured by a network high layer, or k may be included in the third information.

By initiating the activation and/or de-activation of the Scell that does not carry a downlink signal by the user equipment, not only does it solve the problem that the network device has no way of determining when it should initiate the activation and/or de-activation of the SCell that does not carry a downlink signal, but it also helps to reduce the network latency and improve the system throughput.

According to embodiments, the activation or de-activation delay requirement of the Scell may include, without limitation, a requirement regarding a receive timing difference (RTD) between the Scell and the reference cell and/or a requirement regarding a reception power difference between the Scell and the reference cell. According to embodiments, the requirement regarding the RTD and/or the requirement regarding the reception power difference may be determined based on the capability of the user equipment. For example, the requirement regarding the RTD and/or the requirement regarding the reception power difference may be broader if the user equipment has a stronger capability to support that the SCells does not carry a downlink signal, while the requirement regarding the RTD and/or the requirement regarding the reception power difference may be more stringent if the user equipment has a weaker capability to support that the SCell does not carry a downlink signal. By determining the requirement regarding the RTD and/or the requirement regarding reception power difference according to the capability of the user equipment, and by separately formulating activation or de-activation delay requirements for user equipment having different capabilities, the unnecessary waiting time may be avoided, and the reduction of network delay, the improved system throughput and the network energy saving may be better achieved.

As an example, all of the above requirements may be minimum requirements, but are not limited thereto. According to embodiments, different capabilities of different user equipments may correspond to different minimum requirements for the RTD and/or the reception power difference. Alternatively, the requirement regarding the RTD and/or the requirement regarding the reception power difference may affect the activation delay T_{activation_time} of the Scell that does not carry a downlink signal, or may also not affect the activation delay T_{activation_time} of the Scell that does not carry a downlink signal.

According to embodiments, if an activated SCell belongs to FR1 and there is a reference cell that is in an activated state, if the SCell does not carry a downlink signal and does not have SSB measurement timing configuration (SS/PBCH block measurement timing configuration, SMTC), and if the user equipment has a capability to support that the SCell does not carry a downlink signal as indicated in any of the aforementioned capability information, then the activation delay T_{activation_time} of the SCell is X, , X having various possible values, e.g. 3ms, if the following conditions are met,:

- When the frequency separation and/or the relative frequency separation between the SCell and the reference cell is(are) within a certain range, or when the user equipment has different capabilities to support that the SCell does not carry a downlink signal, the RTD between the SCell and the reference cell is within a range of Y, and Y has different values corresponding to different frequency separations and/or relative frequency separations, and there are various possible values of Y such as ±260ns, ±min(a cyclic prefix length, 3μs), where the cyclic prefix is a cyclic prefix corresponding to the maximum subcarrier separation between the SCell and the reference cell; and such as ±(3μs + Y1), there are various possible values of Y1; and

- The reception power difference between the SCell and the reference cell is within a range of Z. There are various possible values for Z, such as 6dB + Z1, and Z1 has different values corresponding to different frequency separations and/or relative frequency separations, such as 0dB.

Specifically, for example, if the activated SCell belongs to FR1 and there is the reference cell that is in the activated state, and if the SCell does not carry a downlink signal and does not have a SSB measurement timing configuration (SS/PBCH block measurement timing configuration, SMTC), the user equipment has a capability to support that the SCell does not carry a downlink signal as indicated in any of the aforementioned capability information, then the activation delay T_{activation_time} of the SCell is X1, X1 having various possible values, e.g. 3ms, if the following conditions are met:

- When the frequency separation and/or the relative frequency separation between the SCell and the reference cell is(are) within a certain range, or when the user equipment has different capabilities to support that the SCell does not carry a downlink signal, the RTD between the SCell and the reference cell is within a range of Y, and Y has different values, such as ±260ns; and

- The reception power difference between the 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 frequency separations and/or relative frequency separations, such as 0dB.

For another example, if the activated SCell belongs to FR1 and there is a reference cell that is in the activated state, if the SCell does not carry a downlink signal and does not have a SSB measurement timing configuration (SS/PBCH block measurement timing configuration, SMTC), and the user equipment has a capability to support that the SCell does not carry a downlink signal as indicated in any of the aforementioned capability information, then the activation delay T_{activation_time} of the SCell is X2, X2 having various possible values, e.g. 3ms, if the following conditions are met:

- When the frequency separation and/or the relative frequency separation between the SCell and the reference cell is(are) within a certain range, or when the user equipment has different capabilities to support that the SCell does not carry a downlink signal, the RTD between the SCell and the reference cell is within a range of Y, and Y has different values, such as ±min(a cyclic prefix length, 3μs), where the cyclic prefix is a cyclic prefix corresponding to the maximum subcarrier separation between the SCell and the reference cell; and

As a further example, if the activated SCell belongs to FR1 and there is a reference cell in the active state, and if the SCell does not carry a downlink signal and does not have a SSB measurement timing configuration (SS/PBCH block measurement timing configuration, SMTC), the user equipment has a capability to support that the SCell does not carry a downlink signal as indicated in any of the aforementioned capability information, then the activation delay T_{activation_time} of the SCell is X3, X3 having various possible values, e.g. 3ms, if the following conditions are met:

- When the frequency separation and/or the relative frequency separation between the SCell and the reference cell is(are) within a certain range, or when the user equipment has different capabilities to support that the SCell does not carry a downlink signal, the RTD between the SCell and the reference cell is within a range of Y, and Y has different values, such as ±(3μs + Y1), there are various possible values of Y1; and

In the above example, the values of X1, X2and X3 may be different or the same.

Optionally, according to embodiments, the method shown in FIG. 4 may further include: receiving a command for activating or de-activating the Scell at a time slot n, and performing an action corresponding to the command at a time no later than a third time, the third time being determined based on a first offset and an activation or de-activation delay time, wherein the first offset is related to a delay time, wherein the delay time is a predetermined value or is determined based on information of the reference cell. According to embodiments, the delay time may include a first delay time and/or a second delay time. For example, the first delay time may be a delay time determined based on a time difference between downlink data transmission and acknowledgement of the reference cell, which may, for example, be equal to a period of reporting Hybrid Automatic Repeat Request (HARQ) acknowledgement of the reference cell. For example, the second delay time may be a delay time determined based on the information of the reference cell, which may, for example, be a delay time determined based on a period of reporting channel status information of the reference cell, such as be equal to the period of reporting the channel status information of the reference cell. For example, when the activated SCell is a SCell that does not carry a downlink signal, if an activation command for the SCell that does not carry a downlink signal is received at a time slot n, the user equipment should be able to perform a first behavior and/or perform an associated action corresponding to the activation command for the SCell that does not carry a downlink signal no later than a time slot

, wherein T_{activation_time} is a SCell activation delay in milliseconds; T_duration1 is a first delay time (e.g., in milliseconds), which may be, for example, the THARQ of the reference cell; T_duration2 is a second delay time (e.g., in milliseconds), which may be, for example, the T_{CSI_reporting} of the reference cell; NR slot length is a time slot length in milliseconds corresponding to the numerology of the activated SCell NR mode (e.g., 1ms for a mode 0, 0.5ms for a mode 1, 0.5ms for a mode 2, and 0.125ms for a mode 3, etc.). The first behavior includes, but is not limited to, transmitting a valid CSI report to the reference cell.

In above, the method performed by the user equipment according to embodiments of the present disclosure has been described with reference to FIG. 4 and in conjunction with the examples, according to which it is possible to realize the network energy saving while ensuring that uplink transmission may be performed normally.

To facilitate understanding of the above methods, two examples of the method performed by the user equipment according to embodiments of the present disclosure are briefly described below with reference to FIGS. 5 and 6. However, the methods performed by the user equipment are not limited to the examples of FIGS. 5 and 6, but are subject to a variety of possible variations.

FIGURE 5 illustrates a flowchart illustrating a first example of a method performed by a user equipment according to embodiments of the present disclosure.

Referring to FIG. 5, at step S510, the user equipment reports capacity information to a network node. The capability information is used to indicate that the user equipment supports that a Scell does not carry a downlink signal.

Next, at step S520, the user equipment obtains information of a reference cell based on a first rule and/or second information received from the network node. For example, the user equipment selects the reference cell based on the first rule and/or the second information received from the network node, thereby obtaining the information of the reference cell.

Subsequently, at step S530, the user equipment determines uplink timing synchronization information and/or uplink power control information of the Scell that does not carry a downlink signal according to the information of the reference cell and/or the first information received from the network node.

Finally, at step S540, the user equipment performs activation and de-activation of the Scell, and/or uplink transmission on the Scell based on the uplink timing synchronization information and/or the uplink power control information. For example, when the uplink transmission is performed on the Scell, a transmission time of an uplink frame may be related to a timing difference between the Scell and the reference cell indicated in the first information and to an uplink transmission timing advance of the reference cell if the Scell does not have a downlink signal.

The details involved in the above steps have all been mentioned in the description with respect to FIG. 4 and are therefore not repeated here.

FIGURE 6 illustrates a flowchart illustrating a second example of a method performed by a user equipment according to embodiments of the present disclosure.

Referring to FIG. 6, at step S610, the user equipment reports capability information to a network node. The capability information is used to indicate that the user equipment supports that a Scell does not carry a downlink signal.

Next, at step S620, the user equipment obtains information of a reference cell based on a first rule and/or second information received from the network node. For example, the user equipment selects the reference cell based on the first rule and/or the second information received from the network node, thereby obtaining the information of the reference cell.

Subsequently, at step S630, the user equipment determines uplink timing synchronization information and/or uplink power control information of the Scell that does not carry a downlink signal according to the information of the reference cell and/or the first information received from the network node.

At step S640, the user equipment transmits third information to the network device. For example, the third information is used to inform the network node that the Scell not carrying a downlink signal needs to be activated and/or de-activated, or, the third information is used to inform the network node that the Scell will be activated and/or de-activated at a predetermined time.

Finally, at step S650, the user equipment performs activation and de-activation of the Scell, and/or uplink transmission on the Scell based on uplink timing synchronization information and/or uplink power control information. For example, when the uplink transmission is performed on the Scell, a transmission time of an uplink frame may be related to a timing difference between the Scell and the reference cell indicated in the first information and to an uplink transmission timing advance of the reference cell if the Scell does not have a downlink signal.

The details involved in the above steps have all been mentioned in the description with respect to FIG. 4, and therefore will not be repeated here.

Above, the methods performed by the user equipment has been described with reference to FIGS. 4 to 6, and below, a method performed by a network node will be described with reference to FIG. 7. In the present disclosure, the network node may be any network device (e.g., a base station device, a sidelink device, etc.), or a network functional entity.

FIGURE 7 illustrates a flowchart illustrating a method performed by a network node according to embodiments of the present disclosure.

Referring to FIG. 7, at step S710, information indicating a timing difference between a reference cell and a Scell is transmitted to a user equipment. For example, the network node may transmit first information to the user equipment, wherein the first information may include information indicating the timing difference between the reference cell and the Scell.

According to embodiments, the reference cell may be determined based on the following methods: the reference cell is determined based on information for indicating the reference cell received from the network node, or the reference cell is determined from among serving cells of the user equipment based on at least one of frequency separations between the secondary cell and the serving cells, relative frequency separations between the secondary cell and the serving cells and signal strength/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 synchronization signal/physical broadcast channel block (SS/PBCH block, SSB).

At step S720, uplink transmission is received on the Scell. According to embodiments, in a case that the Scell does not have a downlink signal, a transmission time of an uplink frame is related to the timing difference and an uplink transmission timing advance of the reference cell. For example, the transmission time of the uplink frame being related to the timing difference and the uplink transmission timing advance of the reference cell includes: the transmission time of the uplink frame satisfies a requirement that the uplink frame transmission takes place before the reception of the first detected path (in time) of the corresponding downlink frame from the reference cell, the time is related to the timing difference and the uplink transmission timing advance of the reference cell.

Optionally, according to embodiments, a reference point for an initial transmission timing control requirement of the initial transmission is determined based on a downlink timing of the reference cell, the timing difference, and the uplink transmission timing advance of the reference cell. For example, the downlink timing of the reference cell is a first time corresponding to a receiving time of a first path on a time domain of a downlink frame, and the first time is received from the reference cell at an antenna of the user equipment for determining the downlink timing by the user equipment.

Optionally, the Scell should satisfy a minimum transmission timing error requirement to ensure that a transmission timing error between the Scell and the reference timing does not exceed a timing error limit value; wherein the reference timing is a second time before the downlink timing of the reference cell, and wherein the second time is determined based on the timing difference and an uplink transmission timing advance of the reference cell.

As mentioned above, optionally, the activation or de-activation of the Scell may be initiated by the user equipment. In this case, optionally, the method shown in FIG. 7 may further include: receiving from the user equipment a notification that the Scell needs to be activated or de-activated, and transmitting to the user equipment a command for activating or de-activating the Scell; or, receiving a notification of activation or de-activation of the Scell from the user equipment, wherein information of a predetermined time at which the Scell is activated or de-activated by the user equipment is included in this notification, or wherein the predetermined time is a predefined value or a value configured by a network high layer. The activation or de-activation delay requirement for the Scell has been described above and will not be repeated here.

Optionally, the method shown in FIG. 7 may further include: transmitting a command for activating or de-activating the Scell to the user equipment at a time slot n, wherein the user equipment performs an action corresponding to the command at a time no later than a third time, the third time being determined based on a first offset and an activation or de-activation delay time, wherein the first offset is related to a delay time, wherein the delay time is a predetermined value or is determined based on information of the reference cell. For example, the delay time includes a first delay time and/or a second delay time, wherein the first delay time is a delay time determined based on a time difference between downlink data transmission and acknowledgement of the reference cell, and the second delay time is a delay time determined based on a period of reporting channel state information of the reference cell.

Optionally, the method shown in FIG. 7 may further include: transmitting to the user equipment information indicating a power difference between the Scell and the reference cell, wherein the uplink power control information of the Scell is determined based on the power difference and uplink power control information of the reference cell.

Optionally, the method shown in FIG. 7 may further include: receiving capacity information reported by the user equipment. According to embodiments, the capability information may be used to indicate that the user equipment supports that the Scell does not carry a downlink signal. The capability information has been described above in the description of FIG. 4, and all the descriptions of the capability information above may be applicable to the method shown in FIG. 7, and therefore will not be repeated here. Based on the capability information, the network node may not transmit a downlink signal to the Scell.

According to the method shown in FIG. 7, since the network node transmits to the user equipment the information indicating the timing difference between the reference cell and the Scell, in the case that the Scell does not have a downlink signal, the transmission time of the uplink frame is related to the timing difference and the uplink transmission timing advance of the reference cell, and therefore it is possible to ensure the correct reception of uplink transmission on the Scell while saving energy in the network.

FIGURES 8 through 10 illustrate schematic diagrams illustrating examples of communication between a user equipment and a network node according to embodiments of the present disclosure.

In order to facilitate a more intuitive understanding of the idea of the present disclosure, below, examples of the communication between the user equipment and the network node are briefly described with reference to FIGS. 8-10. However, it should be understood that FIGS. 8-10 are only the examples and do not indicate that the communication between the user equipment and the network node may only be performed at the flows shown in FIGS. 8-10.

FIGURE 8 illustrates a schematic diagram illustrating a first example of communication between a user equipment and a network node according to embodiments of the present disclosure.

As shown in FIG. 8, 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 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 second information and first information to the user equipment. For example, the second information may be information indicating the reference cell. For example, the first information may be used to indicate a timing difference and/or a power difference between the SCell and the reference cell. In addition, the network node may transmit a MAC-CE message to the user equipment to inform the user equipment which SCell or SCells to be activated. Thereafter, the user equipment may perform the activation for the SCell that does not carry a downlink signal according to the message.

FIGURE 9 illustrates a schematic diagram illustrating a second example of communication between a user equipment and a network node according to embodiments of the present disclosure.

As shown in FIG. 9, 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 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 second information and first information to the user equipment. For example, the second information may be information indicating the reference cell. For example, the first information may be used to indicate a timing difference and/or a power difference between the SCell and the reference cell. Subsequently, the user equipment may transmit third information to the network node. In the example of FIG. 9, the third information is used to inform the network node that the SCell that does not carry a downlink signal needs to be activated and/or de-activated. After receiving the third information, the network node may transmit a MAC-CE message to the user equipment to notify the user equipment of the activation and/or de-activation of the SCell. Thereafter, the user equipment may perform the activation and/or de-activation of the SCell based on the message.

FIGURE 10 illustrates a schematic diagram illustrating a third example of communication between a user equipment and a network node according to embodiments of the present disclosure.

As shown in FIG. 10, 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 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 second information and first information to the user equipment. For example, the second information may be information indicating the reference cell. For example, the first information may be used to indicate a timing difference and/or a power difference between the SCell and the reference cell. Subsequently, the user equipment may transmit third information to the network node. In the example of FIG. 10, the third information is used to inform the network node that the SCell that does not carry a downlink signal will be activated and/or de-activated at a predetermined time. Thereafter, at the predetermined time, the user equipment may directly perform the activation and/or de-activation of the SCell that does not carry a downlink signal.

It is to be noted that although the second information, the first information, the MAC-CE message and the third information are shown as being transmitted in a certain order in the examples of FIGS. 8 to 10, there is no fixed order in which the second information, the first information, the MAC-CE message and the third information are transmitted, and the second information and the first information may be transmitted either before the third information and/or the MAC-CE message or after the third information and/or the MAC-CE message. In addition, there is no fixed order in which the second information and the first information are transmitted, and the second information may be transmitted first, followed by the first information, or the first information may be transmitted first, followed by the second information, or the second information and the first information may be transmitted together.

Furthermore, it should be noted that although the examples of FIGS. 8 to 10 only show that the activation or de-activation of the SCell is performed in the case that the SCell does not have a downlink signal, it should be understood that the basic communication flows between the user equipment and the network node of FIGS. 8 to 9 are also applicable to the uplink transmission on the SCell in the case that the SCell does not have a downlink signal.

FIGURE 11 illustrates a block diagram illustrating a user equipment according to embodiments of the present disclosure. Referring to FIG. 11, the user equipment 1100 may include a transceiver 1101 and a processor 1102, wherein the processor 1102 is coupled to the transceiver 1101 and configured to perform the method performed by the user equipment described above.

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.

In a user equipment, a processor may 1102 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.

FIGURE 12 illustrates a block diagram illustrating a network node according to embodiments of the present disclosure. Referring to FIG. 12, the network node 1200 may include a transceiver 1201 and a processor 1202, wherein the processor 1202 is coupled to the transceiver 1201 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.

FIGURE 13 illustrates a block diagram illustrating a structure of a UE according to various embodiments of the present disclosure. FIG. 13 corresponds to the example of the UE of FIG. 11.

As shown in FIG. 13, the UE according to an embodiment may include a transceiver 1310, a memory 1320, and a processor (e.g. controller) 1330. The transceiver 1310, the memory 1320, and the processor 1330 of the UE may operate according to a communication method of the UE described above. However, the components of the UE are not limited thereto. For example, the UE may include more or fewer components than those described above. In addition, the processor 1330, the transceiver 1310, and the memory 1320 may be implemented as a single chip. Also, the processor 1330 may include at least one processor.

The transceiver 1310 collectively refers to a UE receiver and a UE transmitter, and may transmit/receive a signal to/from a base station. The signal transmitted or received to or from the base station may include control information and data. The transceiver 1310 may include a RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and a RF receiver for amplifying low-noise and down-converting a frequency of a received signal. However, this is only an example of the transceiver 1310 and components of the transceiver 1310 are not limited to the RF transmitter and the RF receiver.

Also, the transceiver 1310 may receive and output, to the processor 1330, a signal through a wireless channel, and transmit a signal output from the processor 1330 through the wireless channel.

The memory 1320 may store a program and data required for operations of the UE. Also, the memory 1320 may store control information or data included in a signal obtained by the UE. The memory 1320 may be a storage medium, such as read-only memory (ROM), random access memory (RAM), a hard disk, a CD-ROM, and a DVD, or a combination of storage media.

The processor 1330 may control a series of processes such that the UE operates as described above. For example, the transceiver 1310 may receive a data signal including a control signal transmitted by the base station, and the processor 1330 may determine a result of receiving the control signal and the data signal transmitted by the base station.

FIGURE 14 illustrates a block diagram illustrating a structure of a base station according to various embodiments of the present disclosure. FIG. 14 corresponds to the example of the network node of FIG. 12.

As shown in FIG. 14, the base station according to an embodiment may include a transceiver 1410, a memory 1420, and a processor (e.g. controller) 1430. The transceiver 1410, the memory 1420, and the processor 1430 of the base station may operate according to a communication method of the base station described above. However, the components of the network entity are not limited thereto. For example, the base station may include more or fewer components than those described above. In addition, the processor 1430, the transceiver 1410, and the memory 1420 may be implemented as a single chip. Also, the processor 1430 may include at least one processor.

The transceiver 1410 collectively refers to a base station receiver and a base station transmitter, and may transmit/receive a signal to/from a terminal. The signal transmitted or received to or from the terminal may include control information and data. The transceiver 1410 may include a RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and a RF receiver for amplifying low-noise and down-converting a frequency of a received signal. However, this is only an example of the transceiver 1410 and components of the transceiver 1410 are not limited to the RF transmitter and the RF receiver.

Also, the transceiver 1410 may receive and output, to the processor 1430, a signal through a wireless channel, and transmit a signal output from the processor 1430 through the wireless channel.

The memory 1420 may store a program and data required for operations of the base station. Also, the memory 1420 may store control information or data included in a signal obtained by the base station. The memory 1420 may be a storage medium, such as read-only memory (ROM), random access memory (RAM), a hard disk, a CD-ROM, and a DVD, or a combination of storage media.

The processor 1430 may control a series of processes such that the network entity operates as described above. For example, the transceiver 1410 may receive a data signal including a control signal transmitted by the terminal, and the processor 1430 may determine a result of receiving the control signal and the data signal transmitted by the terminal.

Alternatively, the transmission time of the uplink frame being related to the timing difference and the uplink frame transmission timing advance of the reference cell includes: the transmission time of the uplink frame satisfies a requirement that the uplink frame transmission takes place before the reception of the first detected path (in time) of the corresponding downlink frame from the reference cell, the time is related to the timing difference and the uplink frame transmission timing advance of the reference cell.

Alternatively, the method further includes: determining a reference point for an initial transmission timing control requirement, wherein the reference point is determined based on a downlink timing of the reference cell, the timing difference, and the uplink transmission timing advance of the reference cell.

Alternatively, the downlink timing of the reference cell is a first time corresponding to a receiving time of a first path on a time domain of a downlink frame, and the first time is received from the reference cell at an antenna of the user equipment for determining the downlink timing by the user equipment.

Alternatively, the secondary cell should satisfy a minimum transmission timing error requirement, to ensure that a transmission timing error between the secondary cell and a reference timing does not exceed a timing error limit value; wherein the reference timing is a second time before a downlink timing of the reference cell, the second time being determined based on the timing difference and the uplink transmission timing advance of the reference cell.

Alternatively, the method further includes: transmitting, to the network node, a notification that the secondary cell needs to be activated or de-activated, receiving a command for activating or de-activating the secondary cell transmitted by the network node, and activating or de-activating the secondary cell according to the command; or transmitting, to the network node, a notification for activating or de-activating the secondary cell, activating or de-activating the secondary cell at a predetermined time, information of the predetermined time being included in the notification or being a predefined value or a value configured by a network high layer.

Alternatively, the method further includes: receiving a command for activating or de-activating the secondary cell at a time slot n, performing an action corresponding to the command at a time no later than a third time, the third time being determined based on a first offset and an activation or de-activation delay time, wherein the first offset is related to a delay time, wherein the delay time is a predetermined value or is determined based on information of the reference cell.

Alternatively, the delay time includes a first delay time and/or a second delay time, wherein the first delay time is a delay time determined based on a time difference between downlink data transmission and acknowledgement of the reference cell, and the second delay time is a delay time determined based on a period of reporting channel state information of the reference cell.

Alternatively, an activation or de-activation delay requirement for the secondary cell includes a requirement regarding a receive timing difference between the secondary cell and the reference cell and/or a requirement regarding a reception power difference between the secondary cell and the reference cell; wherein the requirement regarding the receive timing difference and/or the requirement regarding the reception power difference is determined based on a capability of the user equipment.

Alternatively, the method further includes: determining uplink power control information of the secondary cell according to uplink power control information of the reference cell and a power difference between the secondary cell and the reference cell configured by the network node.

Alternatively, the method further includes: reporting 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 downlink signal in any carrier aggregation scenario, wherein the carrier aggregation scenario includes an intra-band carrier aggregation scenario and an inter-band carrier aggregation scenario;

second capability information indicating that the user equipment only supports that the secondary cell does not carry a downlink signal in an intra-band contiguous carrier aggregation scenario;

third capability information indicating that the user equipment only supports that the secondary cell does not carry a downlink signal in the intra-band carrier aggregation scenario, wherein the intra-band carrier aggregation scenario includes an intra-band contiguous carrier aggregation scenario and an intra-band non-contiguous carrier aggregation scenario;

fourth capability information indicating that the user equipment only supports that the secondary cell does not carry a downlink signal in the inter-band carrier aggregation scenario;

fifth 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 downlink signal.

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

Alternatively, the reference cell is determined based on information for indicating the reference cell received from the network node; or the reference cell is determined from among serving cells of the user equipment based on at least one of frequency separations between the secondary cell and the serving cells, relative frequency separations between the secondary cell and the serving cells and signal strength/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 synchronization signal/physical broadcast channel block (SS/PBCH block, SSB).

According to a second aspect of the embodiments of the present disclosure, there is provided a method performed by a network node in a wireless communication system, the method include: transmitting, to a user equipment, information indicating a timing difference between a reference cell and a secondary cell; and receiving uplink transmission on the secondary cell, wherein a transmission time of an uplink frame is related to the timing difference and an uplink transmission timing advance of the reference cell in a case that the secondary cell does not have a downlink signal.

Alternatively, the transmission time of the uplink frame being related to the timing difference and the uplink transmission timing advance of the reference cell includes: the transmission time of the uplink frame satisfies a requirement that the uplink frame transmission takes place before the reception of the first detected path (in time) of the corresponding downlink frame from the reference cell, the time is related to the timing difference and the uplink transmission timing advance of the reference cell.

Alternatively, a reference point for an initial transmission timing control requirement of the uplink transmission is determined based on a downlink timing of the reference cell, the timing difference, and the uplink transmission timing advance of the reference cell.

Alternatively, the method further includes: receiving, from the user equipment, a notification that the secondary cell needs to be activated or de-activated, transmitting, to the user equipment, a command for activating or de-activating the secondary cell; or receiving, from the user equipment, a notification for activating or de-activating the secondary cell, wherein information of a predetermined time at which the secondary cell is activated or de-activated by the user equipment is included in the notification or is a predefined value or a value configured by a network high layer.

Alternatively, the method further includes: transmitting, to the user equipment, a command for activating or de-activating the secondary cell at a time slot n, wherein the user equipment performs an action corresponding to the command at a time no later than a third time, the third time being determined based on a first offset and an activation or de-activation delay time, wherein the first offset is related to a delay time, wherein the delay time is a predetermined value or is determined based on information of the reference cell.

Alternatively, the method further includes: transmitting, to the user equipment, information indicating a power difference between the secondary cell and the reference cell, wherein uplink power control information of the secondary cell is determined based on the power difference and uplink power control information of the reference cell.

Alternatively, the method further includes: receiving capability information reported by the user equipment, wherein the capability information includes at least one of:

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.

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.

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.

According to the technical solutions provided by the embodiments of the present disclosure, since the user equipment receives the information indicating the timing difference between the reference cell and the Scell from the network node, and the transmission time of the uplink frame is related to the uplink transmission timing advance of the reference cell and the timing difference in the case that the Scell does not have a downlink signal, it is possible to ensure that the uplink transmission may be performed correctly while saving energy in the network.

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.

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

A method performed by a user equipment (UE) in a wireless communication system, the method comprising:

receiving, from a base station, information indicating a timing difference between a reference cell and a secondary cell; and

performing an uplink transmission on the secondary cell,

wherein a transmission time of an uplink frame is related to the timing difference and an uplink transmission timing advance of the reference cell, in a case that the secondary cell does not have a downlink signal.
The method of claim 1,

wherein, in case that the secondary cell satisfies a minimum transmission timing error requirement, a transmission timing error between the secondary cell and a reference timing does not exceed a timing error limit value.
The method of claim 1, further comprising:

transmitting, to the base station, a notification that the secondary cell needs to be activated or de-activated;

receiving, from the base station, a command for activating or de-activating the secondary cell; and

activating or de-activating the secondary cell according to the command.
The method of claim 1, further comprising:

transmitting, to the base station, capability information associated with the secondary,

wherein the capability information is per a component carrier (CC), per a combination of multiple CCs, or per a terminal.
A method performed by a base station in a wireless communication system, the method comprising:

transmitting, to a user equipment (UE), information indicating a timing difference between a reference cell and a secondary cell; and

receiving an uplink transmission on the secondary cell,

wherein a transmission time of an uplink frame is related to the timing difference and an uplink transmission timing advance of the reference cell, in a case that the secondary cell does not have a downlink signal.
The method of claim 5,

wherein, in case that the secondary cell satisfies a minimum transmission timing error requirement, a transmission timing error between the secondary cell and a reference timing does not exceed a timing error limit value.
The method of claim 5, further comprising:

receiving, from the UE, a notification that the secondary cell needs to be activated or de-activated; and

transmitting, to the UE, a command for activating or de-activating the secondary cell.
The method of claim 5, further comprising:

receiving, from the UE, capability information associated with the secondary,

wherein the capability information is per a component carrier (CC), per a combination of multiple CCs, or per a terminal.
A user equipment (UE) in a wireless communication system, the UE comprising:

a transceiver; and

a controller coupled to the transceiver, and configured to:

receive, from a base station, information indicating a timing difference between a reference cell and a secondary cell, and

perform an uplink transmission on the secondary cell,

wherein a transmission time of an uplink frame is related to the timing difference and an uplink transmission timing advance of the reference cell, in a case that the secondary cell does not have a downlink signal.
The UE of claim 9,

wherein, in case that the secondary cell satisfies a minimum transmission timing error requirement, a transmission timing error between the secondary cell and a reference timing does not exceed a timing error limit value.
The UE of claim 9, wherein the controller is further configured to:

transmit, to the base station, a notification that the secondary cell needs to be activated or de-activated,

receive, from the base station, a command for activating or de-activating the secondary cell, and

activate or de-activate the secondary cell according to the command.
The UE of claim 9, wherein the controller is further configured to:

transmit, to the base station, capability information associated with the secondary,

wherein the capability information is per a component carrier (CC), per a combination of multiple CCs, or per a terminal.
A base station in a wireless communication system, the base station comprising:

a transceiver; and

a controller coupled to the transceiver, and configured to:

transmit, to a user equipment (UE), information indicating a timing difference between a reference cell and a secondary cell, and

receive an uplink transmission on the secondary cell,

wherein a transmission time of an uplink frame is related to the timing difference and an uplink transmission timing advance of the reference cell, in a case that the secondary cell does not have a downlink signal.
The method of claim 13,

wherein, in case that the secondary cell satisfies a minimum transmission timing error requirement, a transmission timing error between the secondary cell and a reference timing does not exceed a timing error limit value.
The method of claim 13, wherein the controller is further configured to:

receive, from the UE, a notification that the secondary cell needs to be activated or de-activated, and

transmit, to the UE, a command for activating or de-activating the secondary cell.