Method and apparatus for sib-based cell change in wireless communication system

Abstract

The disclosure relates to a pre-5G communication system, a 5G communication system, or a 6G communication system for supporting higher data rates beyond 4G communication systems, such as long term evolution (LTE). Methods and apparatuses in a wireless communication system. A method of a UE includes receiving a system information block (SIB) from a base station (BS) in a non-terrestrial network (NTN), determining that the SIB includes first neighboring cell information and first timing information associated therewith, determining that the first neighboring cell is not a candidate cell for a cell selection or reselection operation when a current time is before or equal to a time indicated by the first timing information, and determining that the first neighboring cell is a candidate cell for the cell selection or reselection operation when the current time is after the time indicated by the first timing information.

Description

TECHNICAL FIELD

[0001] The disclosure relates generally to a wireless communication system, and more particularly, the disclosure relates to a cell change based on a system information block (SIB) in a wireless communication system. BACKGROUND

[0002] To meet increasing wireless data traffic demands that have arisen since the deployment of 4th-Generation (4G) communication systems, efforts have been made to develop an improved 5th-Generation (5G) or pre-5G communication system. Therefore, 5G or pre-5G communication systems are also called "beyond 4G networks" or "post LTE systems."

[0003] 5G communication systems are considered to be implemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, beamforming, massive Multiple-Input Multiple-Output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna, analog beam forming, and large scale antenna techniques are discussed in 5G communication systems.

[0004] In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud Radio Access Networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), reception-end interference cancellation and the like.

[0005] In 5G systems, Hybrid FSK and QAM Modulation (FQAM) and sliding window superposition coding (SWSC) are developed as advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) are developed as advanced access technology.

[0006] In view of the development of each generation of wireless communication, these technologies have been developed mainly targeting services for humans such as voice calls, multimedia services and data services. As 5G (5th-Generation) communication systems are commercialized, it is expected that the number of connected devices will increase exponentially. These will be increasingly connected to communication networks. Examples of Internet of Things (IoT) can include vehicles, robots, drones, home appliances, displays, smart sensors connected to various infrastructures, construction machines, and factory equipment. Mobile devices are expected to evolve in various forms, such as augmented reality glasses, virtual reality headsets, and hologram devices. In order to provide various services by connecting hundreds of billions of devices and things in the 6G (6th-Generation) era, efforts have been made to develop an improved 6G communication system. For these reasons, the 6G communication system is called a beyond-5G system.

[0007] The 6G communication system is expected to be commercialized around 2030, and its peak data rate will reach 1000 giga (G) bits per second (bps), and the radio latency will be less than 100 microseconds (µsec), so its speed will be 50 times faster than that of the 5G communication system, and the radio latency will be 1 / 10 of that of the 5G communication system.

[0008] To achieve such a high data rate and an ultra-low latency, it has been considered to implement the 6G communication system in a terahertz band (for example, 95 GHz to 3 THz bands). It is expected that, since the path loss and atmospheric absorption of the terahertz band are more severe than those of the millimeter wave band introduced in the 5G, the technologies capable of securing signal transmission distance (that is, coverage) will become more crucial. As major technologies for securing coverage, it is necessary to develop radio frequency (RF) elements, antennas, new waveforms having better coverage than orthogonal frequency division multiplexing (OFDM), beamforming, and massive multiple input multiple output (MIMO), full dimensional MIMO (FD-MIMO), array antennas, and multi-antenna transmission techniques such as large scale antennas. In addition, new technologies regarding improving coverage of the terahertz band signals, such as metamaterials-based lenses and antennas, orbital angular momentum (OAM), and reconfigurable intelligent surface (RIS), have also been discussed.

[0009] In addition, in order to improve the spectral efficiency and overall network performance, the following technologies have been developed for the 6G communication system: a full duplex technology for enabling uplink transmission and downlink transmission to use the same frequency resource at the same time; a network technology for utilizing satellites, high altitude platform stations (HAPS), and the like in an integrated manner; an improved network structure for supporting mobile base stations and the like and implementing network operation optimization and automation and the like; a dynamic spectrum sharing technology through collision avoidance based on spectrum usage prediction; the use of artificial intelligence (AI) in wireless communication, improvement of overall network operation by utilizing AI from the design stage of developing 6G and internalizing end-to-end AI support functions; and a next-generation distributed computing technology for overcoming the limitations of UE computing capability through ultra-high-performance communication and computing resources reachable on the network, such as mobile edge computing (MEC), cloud, and the like. In addition, by designing a new protocol for the 6G communication system, developing a mechanism for implementing a hardware-based secure environment and secure use of data, and developing a technology for maintaining privacy, attempts are being made to enhance connectivity between devices, optimize networks, promote softwareization of network entities, and increase openness of wireless communication.

[0010] It is expected that the development of hyper-connected 6G communication systems, including human-to-machine (P2M) and machine-to-machine (M2M), will bring the next hyper-connected experience. In particular, it is expected that services such as truly immersive extended reality (XR), high-fidelity mobile holograms, and digital replicas can be provided through 6G communication systems. In addition, services such as remote surgery for security and reliability enhancement, industrial automation, and emergency response will also be provided through 6G communication systems, so that these technologies can be applied to various fields such as industry, medicine, automobiles, and home appliances.

[0011] Fifth generation (5G) or new radio (NR) mobile communication is recently growing momentum with global technology activities of various candidate technologies from industry and academia. The candidate enablers of 5G / NR mobile communication include massive antenna technology from a conventional cellular band to a high frequency to provide beamforming gain and support increased capacity; a new waveform (e.g., a new radio access technology (RAT)) to flexibly accommodate various services / applications with different requirements; a new multiple access scheme to support massive connectivity; etc. SUMMARY

[0012] TECHNICAL PROBLEM

[0013] The disclosure relates to a wireless communication system, and more particularly, the disclosure relates to a SIB-based cell change in a wireless communication system.

[0014] TECHNICAL SOLUTION

[0015] In one embodiment, a user equipment (UE) is provided. The UE includes a transceiver configured to receive a system information block (SIB) from a base station (BS) in a non-terrestrial network (NTN). The UE also includes a processor operably coupled to the transceiver, the processor configured to determine that the SIB includes first neighboring cell information and first timing information associated therewith, determine that the first neighboring cell is not a candidate cell for a cell selection or reselection operation when a current time is before or equal to a time indicated by the first timing information, and determine that the first neighboring cell is a candidate cell for the cell selection or reselection operation when the current time is after the time indicated by the first timing information.

[0016] In another embodiment, a method of a UE is provided. The method includes receiving a SIB from a BS in a NTN, determining that the SIB includes first neighboring cell information and first timing information associated therewith, determining that a first neighboring cell is not a candidate cell for a cell selection or reselection operation when a current time is before or equal to a time indicated by the first timing information, and determining that the first neighboring cell is a candidate cell for the cell selection or reselection operation when the current time is after the time indicated by the first timing information.

[0017] In yet another embodiment, a BS in an NTN is provided. The BS includes a processor configured to generate a SIB including first neighboring cell information and first timing information associated therewith. The BS further includes a transceiver operably coupled to the processor, the transceiver configured to transmit the SIB to a UE, wherein: when a current time is before or equal to a time indicated by the first timing information, the first neighboring cell is not determined to be a candidate cell for a cell selection or reselection operation; and when the current time is after the time indicated by the first timing information, the first neighboring cell is determined to be a candidate cell for the cell selection or reselection operation.

[0018] Other technical features can be readily apparent to one skilled in the art from the following figures, descriptions, and claims.

[0019] Before undertaking the detailed description below, it can be advantageous to set forth definitions of certain terms and phrases used in this patent document. The term “couple” and its derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with one another. The terms “transmit,” “receive,” and “communicate,” as well as derivatives thereof, encompass both direct and indirect communication. The terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation. The term “or” is inclusive, meaning and / or. The phrase “associated with” as well as derivatives thereof means to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, be proximate to, be bound to or with, have a property of, have, have a characteristic of, be related to or with, or the like. The term “controller” means any device, system or component that controls at least one operation. Such a controller can be implemented in hardware or a combination of hardware and software and / or firmware. The functionality associated with any particular controller can be centralized or distributed, whether locally or remotely. The phrase “at least” when used with a list of items suggests that different combinations of one or more of the listed items can be used and only one item in the list can be required. For example, “at least one of A, B, and C” includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C.

[0020] Moreover, various functions described below can be implemented or supported by one or more computer programs, each of which is formed from computer readable program code. The terms "application" and "program" refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof, suitable for implementation on a suitable computer readable program code. The phrase "computer readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer readable medium" includes any type of medium capable of storing computer readable program code, such as a solid state drive, a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. The term "non-transitory" is used herein to exclude transitory, propagating signals per se.

[0021] Definitions for other certain words and phrases are provided throughout this patent document. Those of ordinary skill in the art will understand that in many, if not most instances, such definitions apply to prior as well as future uses of such defined words and phrases.

[0022] Benefits

[0023] According to the present disclosure, improvements are present in, and related to, cell change based on SIB (System Information Block). BRIEF DESCRIPTION OF DRAWINGS

[0024] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings in which like parts are marked with like numerals:

[0025] Figure 1 shows an example wireless network, in accordance with embodiments of the present disclosure;

[0026] Figure 2 shows an example gNB, in accordance with embodiments of the present disclosure;

[0027] Figure 3 shows an example UE, in accordance with embodiments of the present disclosure;

[0028] Figure 4 and Figure 5 shows an example wireless transmit and receive path, in accordance with the present disclosure;

[0029] Figure 6 shows an example NTN communication, in accordance with embodiments of the present disclosure;

[0030] Figure 7An example NTN cell according to embodiments of the disclosure is shown;

[0031] Figure 8 An example signaling flow for enhanced cell (re)selection according to embodiments of the disclosure is shown;

[0032] Figure 9 A flow diagram of a method for UE behavior according to embodiments of the disclosure is shown;

[0033] Figure 10 Another example signaling flow for enhanced cell (re)selection according to embodiments of the disclosure is shown; and

[0034] Figure 11 A flow diagram of a method for SIB-based cell change according to embodiments of the disclosure is shown. DETAILED DESCRIPTION

[0035] The following discussion is presented to enable a Figures 1 to 11 The principles of the application described in this patent document should not be interpreted in any way that would limit the scope of the application. Those skilled in the art will understand that the principles of the application can be implemented in any suitably arranged system or device.

[0036] The following documents are hereby incorporated by reference into the present disclosure as if fully set forth herein: 3GPP TS 38.821, v. 16.0.0, “Solutions for NR to support non-terrestrial networks (NTN);” 3GPP TS 38.331 v. 16.2.0, “Radio Resource Control (RRC) protocol specification;” and 3GPP TS 38.304 v. 16.2.0, “User Equipment (UE) procedures in Idle mode and RRC.”

[0037] The following Figures 1-3 Various embodiments implemented using Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA) communication techniques are described. Figures 1-3 The description of the various embodiments does not imply that the described embodiments are the only way(s) in which different embodiments can be implemented. Different embodiments of the disclosure can be implemented in any suitable arrangement.

[0038] Figure 1 An example wireless network according to embodiments of the disclosure is shown. Figure 1The illustrated embodiment of the wireless network is for illustration only. Other embodiments of the wireless network 100 can be used without departing from the scope of the disclosure.

[0039] As Figure 1 illustrated, the wireless network includes a gNB 101 (e.g., base station, BS), a gNB 102, and a gNB 103. The gNB 101 communicates with the gNB 102 and the gNB 103. The gNB 101 also communicates with at least one network 130, such as the Internet, a proprietary Internet Protocol (IP) network, or other data network.

[0040] The gNB 102 provides wireless broadband access to the network 130 for a first plurality of UEs within a coverage area 120 of the gNB 102. The first plurality of UEs includes a UE 111, which can be located in a small business; a UE 112, which can be located in a enterprise (E); a UE 113, which can be located in a WiFi hotspot (HS); a UE 114, which can be located in a first residence (R); a UE 115, which can be located in a second residence (R); and a UE 116, which can be a mobile device (M), such as a cell phone, a wireless laptop, a wireless PDA, or the like. The gNB 103 provides wireless broadband access to the network 130 for a second plurality of UEs within a coverage area 125 of the gNB 103. The second plurality of UEs includes the UE 115 and the UE 116. In some embodiments, one or more of the gNBs 101-103 can communicate with each other and with UEs 111-116 using 5G / NR, LTE, LTE-A, WiMAX, WiFi, or other wireless communication techniques.

[0041] Depending on the network type, the term "base station" or "BS" can refer to any component (or collection of components) configured to provide wireless access to a network, such as a transmit point (TP), transmit-receive point (TRP), an enhanced base station (eNodeB or eNB), a 5G / NR base station (gNB), a macrocell, a femtocell, a WiFi access point (AP), or other wireless-enabled devices. Base stations can provide wireless access to a plurality of remote terminals in accordance with one or more wireless communication protocols, such as 5G / NR Third Generation Partnership Project (3GPP) NR, Long-Term Evolution (LTE), LTE-Advanced (LTE-A), High Speed Packet Access (HSPA), Wi-Fi 802.11a / b / g / n / ac, etc. For the sake of convenience, the terms "BS" and "TRP" are used interchangeably herein to refer to a network infrastructure component that provides wireless access to remote terminals. Further, depending on the network type, the term "user equipment" or "UE" can refer to any component, such as a "mobile station," "subscriber station," "remote terminal," "wireless terminal," "receive point," or "user device." For the sake of convenience, the terms "user equipment" and "UE" are used interchangeably herein to refer to a remote wireless device that wirelessly accesses an access BS, whether the UE is a mobile device (such as a mobile telephone or smartphone) or typically thought of as a fixed device (such as a desktop computer or vending machine).

[0042] Dotted lines show the approximate extents of the coverage areas 120 and 125, which are shown as approximately circular for the purposes of illustration and explanation only. It should be clearly understood that the coverage areas associated with gNBs, such as the coverage areas 120 and 125, can have other shapes, including irregular shapes, depending upon the configuration of the gNBs and variations in the radio environment associated with natural and man-made obstructions.

[0043] As described in more detail below, one or more of the UEs 111-116 include circuitry, programming or a combination thereof for UE assistance information reporting for SIB-based cell change in NTN. In certain embodiments, one or more of the gNBs 101-103 include circuitry, programming or a combination thereof for beam management and coverage enhancement for SIB-based cell change in NTN. Further, the network 100 can be an NTN in which one or more of the gNBs 101-103 are replaced with or receive network access via non-terrestrial nodes, such as satellites.

[0044] Although Figure 1 One example of a wireless network is illustrated, but Figure 1Various modifications can be made. For example, the wireless network can include any number of gNBs and any number of UEs in any suitable arrangement. Furthermore, gNB 101 can communicate directly with any number of UEs and provide these UEs with wireless broadband access to network 130. Similarly, each gNB 102-103 can communicate directly with network 130 and provide the UEs with direct wireless broadband access to network 130. Additionally, gNBs 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.

[0045] Figure 2 An example gNB 102 according to an embodiment of this disclosure is shown. Figure 2 The embodiment of gNB 102 shown is for illustrative purposes only. Figure 1 gNBs 101 and 103 can have the same or similar configurations. However, gNBs have multiple configurations, and Figure 2 This disclosure is not intended to limit the scope to any particular implementation of gNB.

[0046] like Figure 2 As shown, gNB 102 includes multiple antennas 205a-205n, multiple RF transceivers 210a-210n, transmit (TX) processing circuitry 215, and receive (RX) processing circuitry 220. gNB 102 also includes a controller / processor 225, a memory 230, and a backhaul or network interface 235.

[0047] RF transceivers 210a-210n receive input RF signals from antennas 205a-205n, such as signals transmitted by a UE in network 100. RF transceivers 210a-210n down-convert the input RF signals to generate IF or baseband signals. The IF or baseband signals are sent to RX processing circuitry 220, which generates a processed baseband signal by filtering, decoding, and / or digitizing the baseband or IF signals. RX processing circuitry 220 sends the processed baseband signal to controller / processor 225 for further processing.

[0048] The TX processing circuit 215 receives analog or digital data (such as voice data, network data, email, or interactive video game data) from the controller / processor 225. The TX processing circuit 215 encodes, multiplexes, and / or digitizes the output baseband data to generate a processed baseband or IF signal. RF transceivers 210a-210n receive the processed baseband or IF signal output from the TX processing circuit 215 and up-convert the baseband or IF signal into an RF signal transmitted via antennas 205a-205n.

[0049] The controller / processor 225 can include one or more processors or other processing devices to control the overall operation of the gNB 102. For example, the controller / processor 225 could control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceivers 210a-210n, the RX processing circuitry 220, and the TX processing circuitry 215 in accordance with well-known principles. The controller / processor 225 could also support additional functions not directly related to RF transmission and / or reception, such as more advanced wireless communication techniques. For instance, the controller / processor 225 can support beam-forming or directional routing operations in which outgoing signals from / to multiple antennas 205a-205n are weighted differently to effectively steer the outgoing signals in a desired direction. The controller / processor 225 can support any of a variety of other functions as well.

[0050] The controller / processor 225 is also capable of executing programs and other processing to reside in the memory 230. The controller / processor 225 can move data in and out of memory 230 as needed during execution of the programs and other processes.

[0051] The controller / processor 225 is also coupled to a backhaul or network interface 235. The backhaul or network interface 235 allows the gNB 102 to communicate with other devices or systems over a backhaul connection or over a network. The interface 235 could support communications over any suitable wired or wireless connection. For example, when the gNB 102 is implemented as part of a cellular communication system (such as one supporting 5G / NR, LTE, or LTE-A), the interface 235 could allow the gNB 102 to communicate with other gNBs over a wired or wireless backhaul connection (e.g., a wireless network link including non-terrestrial nodes). When the gNB 102 is implemented as an access point, the interface 235 could allow the gNB 102 to communicate over a wired or wireless local area network or over a wired or wireless connection to a larger network (e.g., the Internet). The interface 235 includes any suitable structure supporting communications over a wired or wireless connection, such as an Ethernet or RF transceiver.

[0052] The memory 230 is coupled to the controller / processor 225. The portion of the memory 230 could include RAM, and the other portion of the memory 230 could include flash memory or other ROM.

[0053] Although Figure 2 Although one example of a gNB 102 is shown, various changes could be made to Figure 2 the gNB 102. For example, the gNB 102 could include Figure 2Each component can be any number shown. As a particular example, an access point may include multiple interfaces 235, and a controller / processor 225 may support SIB-based cell changes in the NTN. For example, gNB 102 may be or can be accessed via a non-terrestrial node receiving network, such as a satellite. As another particular example, although shown as a single instance including TX processing circuitry 215 and a single instance including RX processing circuitry 220, gNB 102 may include multiple instances thereof (such as one per RF transceiver). Furthermore, Figure 2 The various components can be combined, further subdivided, or omitted, and other components can be added as needed.

[0054] Figure 3 An example UE 116 according to an embodiment of this disclosure is shown. Figure 3 The embodiment of UE 116 shown is for illustrative purposes only. Figure 1 UEs 111-115 can have the same or similar configurations. However, UEs have multiple configurations, and Figure 3 This disclosure is not intended to limit the scope to any particular implementation of the UE.

[0055] like Figure 3 As shown, UE 116 includes an antenna 305, a radio frequency (RF) transceiver 310, a TX processing circuit 315, a microphone 320, and a receive (RX) processing circuit 325. UE 116 also includes a speaker 330, a processor 340, an input / output (I / O) interface (IF) 345, a touchscreen 350, a display 355, and a memory 360. The memory 360 includes an operating system (OS) 361 and one or more applications 362.

[0056] RF transceiver 310 receives an input RF signal transmitted by a gNB of network 100 from antenna 305. RF transceiver 310 down-converts the input RF signal to generate an intermediate frequency (IF) or baseband signal. The IF or baseband signal is sent to RX processing circuitry 325, which generates a processed baseband signal by filtering, decoding, and / or digitizing the baseband or IF signal. RX processing circuitry 325 sends the processed baseband signal to speaker 330 (e.g., for voice data) or processor 340 for further processing (e.g., for web browsing data).

[0057] The TX processing circuitry 315 receives analog or digital voice data from the microphone 320 or other output baseband data (such as web access data, e-mail, or interactive video game data) from the processor 340. The TX processing circuitry 315 conditions (e.g., encodes, multiplexes, and / or digitizes) the output baseband data to generate a processed baseband or IF signal. The RF transceiver 310 receives the output processed baseband or IF signal from the TX processing circuitry 315 and up-converts the baseband signal or IF signal to an RF signal that is transmitted via the antenna 305.

[0058] The processor 340 can include one or more processors or other processing devices and execute the OS 361 stored in the memory 360 in order to control the overall operation of the UE 116. For example, the processor 340 can control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceiver 310, the RX processing circuitry 325, and the TX processing circuitry 315 in accordance with well-known principles. In some embodiments, the processor 340 includes at least one microprocessor or microcontroller.

[0059] The processor 340 is also capable of executing other processing and program code stored in the memory 360, such as for SIB-based cell change in NTN. For example, in various embodiments, the UE 116 can communicate directly or indirectly with a non-terrestrial node, such as a satellite. The processor 340 can move data into or out of the memory 360 as required by the processing. In some embodiments, the processor 340 is configured to execute the application 362 based on the OS 361 or in response to signals received from gNBs or an operator. The processor 340 is further coupled to the I / O interface 345, which provides the UE 116 with the ability to connect to other devices such as laptop computers and handheld computers. The I / O interface 345 is the communication path between these accessories and the processor 340.

[0060] The processor 340 is also coupled to the touchscreen 350 and the display 355. The operator of the UE 116 can use the touchscreen 350 to enter data into the UE 116. The display 355 can be a liquid crystal display, light emitting diode display, or other display capable of rendering text and / or at least limited graphics, such as from web sites.

[0061] The memory 360 is coupled to the processor 340. Part of the memory 360 can include random access memory (RAM), and another part of the memory 360 can include a flash memory or other read-only memory (ROM).

[0062] Although Figure 3 One example of a UE 116 is shown, but various changes can be made Figure 3 For example, Figure 3The various components in the environment 300 can be combined, further subdivided, or omitted and other components can be added in accordance with particular needs. As a particular example, the processor 340 can be divided into multiple processors such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). Also, while the environment 300 illustrates the UE 116 as being configured as a mobile telephone or smartphone, the UE can be configured to operate as other types of mobile or stationary devices. Figure 3 The UE 116 is illustrated as being configured as a mobile telephone or smartphone, but the UE can be configured to operate as other types of mobile or stationary devices.

[0063] To meet increasing demand with respect to wireless data traffic after deployment of 4G communication systems, efforts have been made to develop and deploy 5G / NR communication systems. The 5G / NR communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 28 GHz or 60 GHz bands, so as to accomplish higher data rates or in lower frequency bands such as 6 GHz, to enable robust coverage and mobility support. To decrease the propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques have been discussed in 5G / NR communication systems.

[0064] In addition, in 5G / NR communication systems, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, a technology for reception-end interference cancellation, cooperative communication, coordinated multi-points (CoMP), reception-end interference cancellation, and the like.

[0065] Since certain embodiments of the present disclosure can be implemented in 5G systems, the discussion of 5G systems and their related frequency bands is for reference only. However, the present disclosure is not limited to 5G systems or frequency bands associated therewith, and embodiments of the present disclosure can be used in conjunction with any frequency band. For example, aspects of the present disclosure can also be applied to 5G communication systems, 6G or even higher versions of deployment, which can use terahertz (THz) bands.

[0066] The communication system includes a downlink (DL) that refers to transmission from a base station or one or more transmission points to a UE and an uplink (UL) that refers to transmission from a UE to a base station or one or more reception points.

[0067] A time unit for DL signaling or UL signaling on a cell is referred to as a slot, and can include one or more symbols. A symbol can also be used as an additional time unit. A frequency (or bandwidth (BW)) unit is referred to as a resource block (RB). One RB includes a number of subcarriers (SCs). For example, a slot can have a duration of 0.5 milliseconds or 1 millisecond, including 14 symbols, an RB can include 12 SCs, an SC interval is 15 KHz or 30 KHz, and the like.

[0068] DL signals include data signals conveying information content, control signals conveying DL control information (DCI), and reference signals (RS) also known as pilot signals. A gNB transmits data information or DCI through a corresponding physical DL shared channel (PDSCH) or physical DL control channel (PDCCH). A PDSCH or PDCCH can be transmitted over a variable number of slot symbols including one slot symbol. For brevity, a DCI format scheduling a UE’s PDSCH reception is referred to as a DL DCI format, and a DCI format scheduling a physical uplink shared channel (PUSCH) transmission from a UE is referred to as a UL DCI format.

[0069] A gNB transmits one or more of multiple types of RS including channel state information RS (CSI-RS) and demodulation RS (DMRS). A CSI-RS is mainly used for a UE to perform measurements and provide CSI to the gNB. For channel measurements, a non-zero-power CSI-RS (NZP CSI-RS) resource is used. For interference measurement reporting (IMR), a CSI interference measurement (CSI-IM) resource associated with a zero-power CSI-RS (ZP CSI-RS) configuration is used. A CSI process includes a NZP CSI-RS and a CSI-IM resource.

[0070] A UE can determine CSI-RS transmission parameters through DL control signaling or higher layer signaling (such as radio resource control (RRC) signaling) from a gNB. Transmission instances of a CSI-RS can be indicated by DL control signaling or configured by higher layer signaling. A DMRS is transmitted only in a BW of a corresponding PDCCH or PDSCH, and a UE can use the DMRS to demodulate data or control information.

[0071] Figure 4 and Figure 5An example wireless transmit and receive path is shown according to this disclosure. In the following description, the transmit path 400 can be described as being implemented in a gNB (such as gNBs 102), while the receive path 500 can be described as being implemented in a UE (such as UEs 116). However, it can be understood that the receive path 500 can be implemented in a gNB, while the transmit path 400 can be implemented in a UE. In some embodiments, the receive path 500 is configured to support SIB-based cell change in NTN as described in embodiments of this disclosure.

[0072] As shown in FIG. 4, the transmit path 400 includes a channel coding and modulation block 405, a serial-to-parallel (S-to-P) block 410, a size N inverse fast Fourier transform (IFFT) block 415, a parallel-to-serial (P-to-S) block 420, an add cyclic prefix block 425, and a Figure 4 Figure 5 As shown in FIG. 5, the receive path 500 includes a down-converter (DC) 555, a remove cyclic prefix block 560, a serial-to-parallel (S-to-P) block 565, a size N fast Fourier transform (FFT) block 570, a parallel-to-serial (P-to-S) block 575, and a channel decoding and demodulation block 580.

[0073] As shown in FIG. 4, the channel coding and modulation block 405 receives a set of information bits, applies coding (such as a 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 modulation symbols. Figure 4

[0074] The serial-to-parallel block 410 converts (such as de-multiplexes) the serial modulated symbols to parallel data in order to generate N parallel symbol streams, where N is the IFFT / FFT size used in the gNB 102 and the UE 116. The size N inverse fast Fourier transform (IFFT) block 415 performs an IFFT operation on the N parallel symbol streams to generate time-domain output signals. The parallel-to-serial block 420 converts (such as multiplexes) the parallel time-domain output symbols from the size N inverse fast Fourier transform (IFFT) block 415 in order to generate a serial time-domain signal. The add cyclic prefix block 425 inserts a cyclic prefix to the time-domain signal. The up-converter 430 modulates (such as up-converts) the output of the add cyclic prefix block 425 to an RF frequency for transmission via a wireless channel. The signal can also be filtered at baseband before conversion to the RF frequency.

[0075] The RF signal transmitted from the gNB 102 arrives at the UE 116 after passing through the wireless channel, and operations performed at the UE 116 are substantially inverses of the operations performed at the gNB 102.

[0076] As shown in FIG. 5, the channel coding and modulation block 580 receives a set of information bits, applies coding (such as a 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 modulation symbols. Figure 5 ​​As shown, the down-converter 555 down-converts the received signal to a baseband frequency and the remove cyclic prefix block 560 removes the cyclic prefix to generate a serial time-domain baseband signal. The serial-to-parallel block 565 converts the time-domain baseband signal to parallel time-domain signals. The size N FFT block 570 performs an FFT algorithm to generate N parallel frequency-domain signals. The parallel-to-serial block 575 converts the N parallel frequency-domain signals to a sequence of modulation symbols. The channel decoding and demodulation block 580 demodulates and decodes the modulation symbols to recover the original input data stream.

[0077] Each of the gNBs 101-103 can implement a transmit path 400 as Figure 4 shown to transmit in the downlink to UEs 111-116 and can implement a receive path 500 as Figure 5 shown to receive in the uplink from UEs 111-116. Similarly, each of the UEs 111-116 can implement a transmit path 400 to transmit in the uplink to the gNBs 101-103 and can implement a receive path 500 to receive in the downlink from gNBs 101-103.

[0078] Figure 4 Each of the components in Figure 5 may be implemented using only hardware or using a combination of hardware and software / firmware. As a specific example, Figure 4 and Figure 5 At least some of the components in may be implemented in software, while others can be implemented by configurable hardware or a mixture of software and configurable hardware. For example, the FFT blocks 570 and the IFFT blocks 515 can be implemented as configurable software algorithms, where the value of N is modified according to the implementation.

[0079] While described as using FFT and IFFT, this is merely an illustrative example and is not to be construed as limiting the scope of the disclosure. Other types of transforms can be used, such as a discrete Fourier transform (DFT) and inverse discrete Fourier transform (IDFT) functions. It can be understood that for DFT and IDFT functions, the value of the variable N can be any integer (such as 1, 2, 3, 4, etc.), while for FFT and IFFT functions, the value of the variable N can also be any integer that is a power of 2 (such as 1, 2, 4, 8, 16, etc.).

[0080] Figure 4 While Figure 4 illustrate examples of wireless transmit and receive paths, various changes can be made to Figure 5 and 5 For example, Figure 4 and Figure 5The various components in the diagram can be combined, further subdivided, or omitted and additional components can be added according to particular needs. Further, Figure 6 and Figure 1 are intended to illustrate examples of types of transmit and receive paths that can be used in a wireless network. Any other suitable architecture can be used to support wireless communication in a wireless network.

[0081] Figure 6 An exemplary NTN communication network 600 according to embodiments of the disclosure is shown. The NTN communication network 600 can be implemented, for example, in the network 100 in Figure 6 FIG. 1. Figure 7 The embodiment of the NTN communication network 600 shown is for illustration only.

[0082] In the Third Generation Partnership Project (3GPP) wireless standards, a new radio access technology (NR) is being discussed as a 5G wireless communication technology. One of the NR features being discussed is NTN. NTN refers to a network or network segment that uses RF resources on a satellite (or unmanned aerial system (UAS) platform), such as Figure 1 shown.

[0083] NTNs typically have the following elements: (1) one or more satellite gateways connecting the non-terrestrial network to a public data network; (2) GEO satellites fed by one or more satellite gateways deployed over the satellite target coverage (e.g., regional or even continental coverage). It can be assumed that UEs in a cell are served by only one satellite gateway; (3) non-GEO satellites served continuously by one or more satellite gateways at a time. The system ensures service and feeder link continuity between consecutive serving satellite gateways with sufficient duration for mobility anchoring and handover; (4) feeder links or radio links between satellite gateways and satellites (or UAS platforms); (5) service links or radio links between user equipment and satellites (or UAS platforms); (6) satellites (or UAS platforms), which can implement transparent or regenerative (with on-board processing) payloads. Satellites (or UAS platforms) generate beams, typically several beams over a given service area defined by a field of view. The coverage area of a beam is typically elliptical. The satellite (or UAS platform) field of view depends on the on-board antenna pattern and minimum elevation angle; (7) transparent payload: radio frequency filtering, frequency conversion, and amplification. The waveform signal of the payload is thus not changed; (8) regenerative payload: radio frequency filtering, frequency conversion, and amplification, and demodulation / decoding, switching and / or routing, encoding / modulation. This is effectively equivalent to having full or partial base station functionality (e.g., gNB) on the satellite (or UAS platform); (9) optionally, in the case of a constellation of satellites, inter-satellite links (ISL). This can require a regenerative payload on the satellite. ISLs can operate in RF frequencies or optical bands; and / or (10) UEs served by a satellite (or UAS platform) within the target service area.

[0084] Figure 7 An exemplary NTN cell 700 according to embodiments of the present disclosure is shown. For example, the NTN cell 700 can be implemented in a cell of the network 100 in Figure 7 FIG. 1. Figure 8 The embodiment of the NTN cell 700 shown is for illustration only.

[0085] Figure 1 One example of how an NTN can provide a cell that is fixed relative to a particular location on Earth at a particular time is illustrated. This can be achieved by an NTN platform that generates steerable beams whose coverage areas are fixed on the ground. Satellite 1 (SAT1) (also referred to herein as low earth orbit 1 (LEO-1)) and satellite 2 (SAT2) (also referred to herein as LEO2) are moving from west to east. T1, T2, and T3 are particular consecutive durations of time (e.g., T1 is between absolute time tl to t2, T2 is between absolute time t2 to t3, and T3 is between absolute time t3 to t4).

[0086] During the T1 duration, SAT1 provides NR service to a first cell location on Earth, and SAT2 provides NR service to a second cell location on Earth. During the T2 duration, both SAT1 and SAT2 provide NR service to the second cell location on Earth. Note that the physical cell IDs (physical cell IDs are also referred to as PCIs herein) of SAT1 and SAT2 at the second cell location on Earth can be different, meaning that the second cell location on Earth is covered by two PCIs, and each PCI and associated NR service is provided by each satellite (e.g., SAT1 and SAT 2). For example, during the T2 duration, the second cell location on Earth is served by PCI #N through SAT1, while the second cell location on Earth is served by PCI #M through SAT2. However, PCI #M of SAT2 can disappear sooner or later, as SAT2 can serve a third cell location on Earth in the next T3 duration. Therefore, during the T2 duration, an effective mechanism is needed to move the UEs served by PCI #M of SAT2 to be served by PCI #N of SAT1.

[0087] Figure 8 An example signaling flow 800 for enhanced cell (re)selection according to embodiments of the disclosure is shown. For example, the signaling flow 800 can be performed by UEs such as 111-116 and BSs such as 101-103, as shown. Figure 8 The embodiments of the signaling flow 800 shown are for illustration only. Figure 8 The embodiments of the signaling flow 800 shown are for illustration only. Figure 8 One or more components shown in FIG. 11 can be implemented in dedicated circuitry configured to perform the functions described, or one or more components can be implemented by one or more processors executing instructions to perform the functions described.

[0088] Figure 7 An example of the signaling flow to the provided mechanism is shown. As shown, Figure 7 When the T2 duration comes, the gNB for SAT1 and the gNB for SAT2 provide assistance information to the UEs located in the cell with its own PCI. The gNB for SAT1 provides temporary blocked cell information. This information includes physical cell ID information (possibly with frequency information) and timer information. Once the UEs served by SAT1 receive this information, the UEs start the indicated timer, and while the indicated timer is running, the UEs do not consider the cell with the indicated PCI (possibly on the indicated frequency) in cell (re)selection. If the indicated timer expires, the UEs return to the normal cell (re)selection procedure. For example, based on Figure 7In the example described in, if the gNB of SAT1 provides a UE in a cell served by SAT1 with temporary blocking cell information including PCI#M (served by SAT2) and a timer T2-1, the UE starts timer T2-1 and does not consider a cell with PCI#M in the same frequency (intra-frequency) in cell (re)selection while timer T2-1 is running.

[0089] Note that if frequency information is included, it can be assumed that the cell with PCI#M in the indicated frequency (inter-frequency) is considered in cell (re)selection while timer T2-1 is running. Although Figure 7 An example is shown where this information is provided by SIB, but it can also be signaled by other means than SIB, e.g. by dedicated RRC signaling, common physical control signaling or MAC control information, etc. If timer T2-1 expires, the UE returns to the normal cell (re)selection procedure without restrictions.

[0090] The gNB for SAT2 provides redirection information. This information includes physical cell ID information (possibly with frequency information) and timer information.

[0091] Once a UE served by SAT2 receives this information, the UE starts the indicated timer, the UE performs cell (re)selection to a cell with the indicated physical cell ID before the timer expires, and once the UE (re)selects (or camps) on a cell, the UE does not consider the previous serving cell (the cell where the UE received the redirection information) in cell (re)selection while the indicated timer is running. If the indicated timer expires, the UE returns to the normal cell (re)selection procedure.

[0092] For example, based on Figure 8 In the example described in, if the gNB of SAT2 provides a UE in a cell served by SAT2 with redirection information including PCI#N (served by SAT1) and a timer T2-2, the UE starts timer T2-2, performs cell (re)selection to a cell with PCI#N before timer T2-2 expires, and once the UE (re)selects (or camps) on a cell with PCI#N, the UE does not consider the previous serving cell with PCI#M in the previous frequency (the cell where the UE received the redirection information and the frequency) in cell (re)selection while timer T2-2 is running.

[0093] Although Figure 8 An example is shown where this information is provided by SIB, but it can also be signaled by other means than SIB, e.g. by dedicated RRC signaling, common physical control signaling or MAC control information, etc. If timer T2-2 expires, the UE returns to the normal cell (re)selection procedure without restrictions.

[0094] Note that if timers T2-1 and T2-2 are the same, there can be no timer T2-2 in the signaling provided by the gNB of SAT2. In this case, once the UE (re)selects (or camps) on a cell with PCI#N, the T2-1 provided by the gNB of SAT1 can be used for the purpose of timer T2-2. Note also that although Figure 9 Examples are described based on a single cell in the signaling provided by the gNB of SAT1 and the gNB of SAT2, multiple cells can be included in the signaling provided by the gNB of SAT1 and the gNB of SAT2, in which case, while timer T2-1 is running, the UE served by the gNB of SAT1 does not consider the multiple cells indicated in the cell (re)selection, when the UE receives the redirection information, the UE served by the gNB of SAT2 can perform cell (re)selection on any of the multiple cells indicated.

[0095] Note also that although Figure 1An example is described based on timers (e.g., timers T2-1 and T2-2), but instead of timers, absolute timing information can be signaled and used. In this case, the UE has GNSS capability, so the UE knows when the indicated absolute timing information is. If absolute timing information #3-1 is signaled (replacing timer T2-1), the UE served by PCI #N (SAT1) does not consider the cell with PCI #M in cell (re)selection if the current time is before (or equal to) the time indicated by absolute timing information #3-1. If the current time is after (or equal to) the time indicated by absolute timing information #3-1, the UE can consider the cell with PCI #M in cell (re)selection. If absolute timing information #3-2 is signaled (replacing timer T2-2), the UE served by PCI #M (SAT2) performs cell (re)selection on the indicated cell with PCI #N before the time indicated by absolute timing information #3-2, and once the UE (re)selects (or camps) on the cell with PCI #N, the UE does not consider the previous serving cell with PCI #M in cell (re)selection if the current time is before (or equal to) the time indicated by absolute timing information #3-2, where the UE receives the redirection information in cell (re)selection. If the current time is after (or equal to) the time indicated by absolute timing information #3-2, the UE can consider the previous serving cell with PCI #M in cell (re)selection. Note that if absolute timing information #3-1 and absolute timing information #3-2 are the same, absolute timing information #3-2 can not exist in the signaling provided by the gNB of SAT2. In this case, once the UE (re)selects (or camps) on the cell with PCI #N, absolute timing information #3-1 provided by the gNB of SAT1 can be used for the purpose of absolute timing information #3-2.

[0096] Figure 9 A flowchart illustrating a method 900 for UE behavior according to embodiments of the present disclosure is shown. For example, the method 900 can be performed by a UE such as the UE 111-116 shown. Figure 9 Figure 9 Embodiments of the method 900 shown are for illustration only. Figure 10 One or more components shown in FIG. 11-16 can be implemented in dedicated circuitry configured to perform the recited functions, or one or more components can be implemented by one or more processors executing instructions to perform the recited functions.

[0097] Figure 1 ​An example of corresponding UE behavior is shown. The UE receives system information (or SIB) in a serving cell (step 901). If the UE receives temporary blocking cell information in the received system information (or SIB) including PCI information (e.g., PCI#M), frequency information, and timer information (e.g., timer T2-1), the UE starts timer T2-1, and excludes the cell with PCI#M in cell (re)selection in the same frequency (if frequency information is not included) or in the indicated frequency (if frequency information is included) while timer T2-1 is running (steps 911 and 921).

[0098] If timer T2-1 expires, the UE applies normal cell (re)selection (step 931). If the UE receives redirection information in the received system information (or SIB) including PCI information (e.g., PCI#N), frequency information, and timer information (e.g., timer T2-2), the UE starts timer T2-2, and performs cell (re)selection to the cell with PCI#N in the same frequency (if frequency information is not included) or in the indicated frequency (if frequency information is included) before timer T2-2 expires (steps 941 and 951).

[0099] The cell (re)selection can be done based on the measured radio channel conditions (as defined in 3GPP standards, such as TS 38.304) or based on new standards to be introduced for NTN. As a new standard, for example, to (re)select a cell, a configured minimum (or maximum) propagation delay between a satellite and a UE can be met (assuming satellite position related information is provided by system information and UE position information is provided by its own GNSS), or a configured minimum (or maximum) distance between a reference point and a UE can be met (assuming reference point related information is provided by system information and UE position information is provided by its own GNSS), or a configured minimum (or maximum) UL timing advance between a satellite and a UE (or between a gNB of a satellite and a UE) can be met (assuming satellite position / gNB position related information is provided by system information and UE position information is provided by its own GNSS).

[0100] As a result of the cell (re)selection, if the UE camps on the cell with PCI#N, the UE excludes the cell where the UE receives redirection information in cell (re)selection while timer T2-2 is running (step 961). If timer T2-2 expires, the UE applies normal cell (re)selection (step 971). If the UE does not receive any temporary blocking cell information or redirection information, the UE applies normal cell (re)selection (step 981).

[0101] The PCI#M of SAT2 can be eliminated sooner or later as SAT2 can serve a third cell location on earth in the next T3 duration. In T3, if SAT2 switches the serving location from the second cell location on earth to a third cell location on earth, all UEs located in the second cell location on earth served by SAT2 can perform cell (re)selection on the cell served by SAT1. This can cause significant congestion problem as all massive UEs perform cell (re)selection on the cell served by SAT2 (almost) simultaneously (e.g. around T3). Therefore, an efficient mechanism is needed to enable UEs to perform cell (re)selection on the new target cell while avoiding possible congestion.

[0102] Figure 10 Another example signaling flow 1000 for enhanced cell (re)selection according to embodiments of the present disclosure is shown. For example, as Figure 10 shown, the signaling flow 1000 can be performed by UEs such as 111-116 and BSs such as 101-103. Figure 10 The embodiments of the signaling flow 1000 shown are for illustration only. Figure 10 One or more of the components shown in FIG. 11 can be implemented in specialized circuitry configured to perform the functions described, or one or more of the components can be implemented by one or more processors executing instructions to perform the functions described.

[0103] Figure 7 An example of the signaling flow to the provided cell (re)selection mechanism is shown. As Figure 10 shown, the gNB of SAT2 (step 1003) provides assistance information (step 1001) to UEs located in the second cell location on earth before T3 arrives. The assistance information includes target cell information (including PCI of the target cell, etc.), switching time (or an alternative timer), and a distributed cell (re)selection indicator (step 1011).

[0104] Note that in step 1011, the information can be sent to UEs through SIB. If the distributed cell (re)selection indicator is set, the UEs perform cell (re)selection on the indicated target cell according to steps 1021 and 1031. Otherwise, the UEs perform cell (re)selection on the indicated target cell at the indicated switching time. The PCI of the target cell indicates the PCI of the next cell which can serve UEs mainly in the corresponding location on earth after the indicated switching time (or the indicated timer expires).

[0105] For example, in Figure 10In the scenario described in the background, if the handover time indication T3, the PCI of the target cell indicates the PCI of SAT1 at the second cell location on the earth, which can serve the UEs in the second cell location mainly after the handover time. The handover time indicates the timing when the current serving cell can disappear in the corresponding cell location on the earth and the new incoming cell can become the new serving cell for the UEs in this location. Therefore, the UEs in this location can perform cell (re)selection to the new target cell at the latest at the handover time. Note that the handover time can be provided as absolute timing information (e.g., GPS timing, absolute number of units from a reference timing delivery, etc.) or a timer (e.g., a timer value related to the message reception or some other indicated time).

[0106] It can be assumed that the distributed cell (re)selection indicator is set. Then, the UE derives the timing of the cell (re)selection to the target cell using the UE ID (e.g., s-temporary mobile subscription identifier (s-TMSI) or international mobile subscriber identity (IMSI) of the UE, etc.) and the received handover time (or timer) (step 1021).

[0107] Note that the S-TMSI is a temporary UE identity provided by the core network, which uniquely identifies a UE within a tracking area, as introduced in 3GPP standard specification TS 23.003. It should also be noted that the 5G-S-TMSI is considered for NR (5GC) specific S-TMSI. One example of deriving the timing of the cell (re)selection to the target cell can be: (1) the UE first calculates the total number of slots (e.g., M slots) (or any other timing unit item) until the handover time; and (2) the UE calculates the value of {UE id MOD M} (let’s call it N value), then the timing of performing the cell (re)selection to the target cell is after N slots can pass. Note that if a timer is provided in step 1011, the UE first calculates the total number of slots (or any other timing unit item) corresponding to the timer value indicated in (1) above.

[0108] Another example of deriving the timing of the cell (re)selection to the target cell can be a random selection of the timing during the time period until the handover time (or until the timer expires if a timer is provided in step 1011).

[0109] Note that if the timer is provided in step 1011, the UE starts the timer upon reception in step 1011. Once the timing of the cell (re)selection to the target cell is determined in step 1021, the UE performs the cell (re)selection to the target cell in step 1022 (e.g., step 1031) at the timing determined in step 1022. When the UE performs the cell reselection to the target cell, the UE can consider the target cell has higher cell reselection priority than other cells in the cell reselection even in the case that the current serving cell and the target cell are in the same frequency.

[0110] In the case of the higher cell reselection priority, the UE can camp on the target cell if the measurement result of the target cell meets the gNB-configured threshold (e.g., if the measurement result of the target cell is better than the gNB-configured threshold).

[0111] Note that although not described in Figure 10 , the corresponding threshold information for the cell reselection to the cell with the higher priority in the same frequency (e.g., the cell reselection in the same frequency can be considered as the intra-frequency cell reselection) can be included in step 1011.

[0112] Although not shown in Figure 11 , as another example, step 1011 can further include the start time of the cell reselection to the indicated target cell. In this case, in step 1021, the UE considers the total number of slots (or any other timing unit item) between the indicated start time and the handover time, and the timing of the cell (re)selection to the target cell is after N slots from the indicated start time. And if the timer is provided in step 1011, the UE starts the timer at the indicated start time for the cell (re)selection to the target cell.

[0113] If the distributed cell (re)selection indicator is not set in step 1011, the UE performs the cell (re)selection to the target cell at the indicated handover time (or the indicated timer expires). Note that if the timer is included in step 1011, the UE starts the timer upon reception of step 1011).

[0114] When the UE performs cell reselection to a target cell, the UE can consider that the target cell has a higher cell reselection priority than other cells in the cell reselection (also referred to as intra-frequency cell reselection) even in the case where the current serving cell, the target cell, and other cells are in the same frequency. In the case of the higher cell reselection priority, the UE can camp on the target cell if the measurement result of the target cell satisfies a threshold value configured by the gNB (for example, if the measurement result of the target cell is better than the gNB configuration threshold value).

[0115] Note that although not shown in Figure 1 , step 1011 can include corresponding threshold value information for cell reselection to a cell having a higher cell reselection priority in intra-frequency cell reselection.

[0116] Figure 11 A flowchart of a method 1100 for SIB-based cell change according to embodiments of the present disclosure is shown. For example, the method 1100 can be performed by a UE such as the UE 102 shown in Figure 11 . Figure 11 Embodiments of the method 1100 shown in ​ may be implemented in dedicated circuitry configured to perform the functions described, or one or more components can be implemented by one or more processors executing instructions to perform the functions described.

[0117] As shown in ​ , the method 1100 starts at step 1102. In step 1102, the UE receives a SIB from a BS in an NTN.

[0118] Subsequently, in step 1104, the UE determines that the SIB includes first neighboring cell information and first timing information associated therewith.

[0119] Next, in step 1106, the UE determines that the first neighboring cell is not a candidate cell for a cell selection or reselection operation when a current time is before or equal to a time indicated by the first timing information.

[0120] In one embodiment, the time is indicated by the first timing information via a timer or an absolute time, and the time indicates a timing instance at which the first neighboring cell stops serving an area.

[0121] In one embodiment, the first neighboring cell information includes a first physical cell identifier (PCI), first frequency information of the first neighboring cell, and information associated with the first timing information. In such an embodiment, the first frequency information is omitted when a first frequency included in the first frequency information is a same frequency as a frequency of a serving cell.

[0122] Finally, in step 1108, the UE determines that the first neighboring cell is a candidate cell for a cell selection or reselection operation when a current time is after a time indicated by the first timing information.

[0123] In one embodiment, the UE further determines whether the SIB includes redirection information, and performs a cell selection or reselection operation for the second neighboring cell based on a determination that the SIB includes the redirection information.

[0124] In such an embodiment, the redirection information includes a second PCI, second frequency information of the second neighboring cell, and information associated with second timing information. In such an embodiment, the second frequency information is omitted when a second frequency included in the second frequency information is a same frequency as a frequency of the serving cell.

[0125] In such an embodiment, the second timing information indicates a second time via a timer or an absolute time, and the second time indicates a timing instance when the serving cell stops a service area.

[0126] In one embodiment, the UE further performs a cell selection or reselection operation for the second neighboring cell when a current time is before or equal to a time indicated by the second timing information, and the previous serving cell is not a candidate cell for the cell selection or reselection operation when the UE camps on the second neighboring cell when the current time is before or equal to the time indicated by the second timing information.

[0127] In one embodiment, the UE further determines that the previous serving cell is a candidate cell for the cell selection or reselection operation when a current time is after a time indicated by the second timing information.

[0128] The above flowcharts illustrate example methods that can be implemented in accordance with the principles of the present disclosure, and various changes can be made to the methods illustrated in the flowcharts herein. For example, while shown as a series of steps, various steps in each figure could overlap, occur in parallel, occur in a different order, or occur multiple times. In another example, steps can be omitted or replaced.

[0129] While this application has been described in example embodiments, it will be appreciated that those skilled in the art can devise various changes and modifications without departing from the scope of the application. The application is intended to cover all such changes and modifications that come within the scope of the appended claims. No description in the present application should be understood as indicating any particular element, step or function is an essential element necessary for the practice of the application. The scope of the patent topic is defined by the claims.

Claims

1. A user equipment (UE) in a wireless communication system, the UE comprising: a transceiver; and a processor operably coupled to the transceiver, the processor configured to: receive, from a base station (BS) in a non-terrestrial network (NTN), a system information block (SIB), determine that the SIB includes neighbor cell information of a first neighbor cell and first timing information associated with the first neighbor cell, perform a measurement on the first neighbor cell before a time indicated by the first timing information, and perform a cell reselection based on the measurement on the first neighbor cell. 2.The UE of claim 1, wherein: the first timing information is absolute timing information, and the time indicates a timing instance at which a serving cell stops serving a current serving area. 3.The UE of claim 1, wherein: the neighbor cell information includes a first physical cell identifier (PCI), and the cell reselection is performed on a cell indicated by the first PCI.

4. The UE of claim 1, wherein, the processor is further configured to: determine that the SIB includes redirection information; and based on the determination that the SIB includes the redirection information, perform a cell selection or reselection on a second neighbor cell. 5.The UE of claim 4, wherein: the redirection information includes a second PCI, second frequency information of the second neighbor cell, and second timing information associated with the second neighbor cell. 6.The UE of claim 5, wherein: the second timing information indicates a second time via an absolute time; and the second time indicates a timing instance at which the second neighbor cell stops serving an area.

7. The UE of claim 4, wherein, the processor is further configured to: perform the cell selection or reselection on the second neighbor cell when a current time is before or equal to the time indicated by the second timing information; and determine that a previous serving cell is not a candidate cell for the cell selection or reselection when the UE camps on the second neighbor cell and when the current time is before or equal to the time indicated by the second timing information.

8. The UE of claim 7, wherein, the processor is further configured to determine that the previous serving cell is a candidate cell for the cell selection or reselection operation when the current time is after the time indicated by the second timing information. 9.A method performed by a user equipment (UE) in a wireless communication system, comprising: receiving, from a base station (BS) in a non-terrestrial network (NTN), a system information block (SIB); determining that the SIB includes neighbor cell information of a first neighbor cell and first timing information associated with the first neighbor cell, performing a measurement on the first neighbor cell before a time indicated by the first timing information, and performing a cell reselection based on the measurement on the first neighbor cell. 10.The method of claim 9, wherein: the first timing information is absolute timing information, and the time indicates a timing instance at which a serving cell stops serving a current serving area. 11.The method of claim 9, wherein: the first neighbor cell information includes a first physical cell identifier (PCI), and the cell reselection is performed on a cell indicated by the first PCI.

12. A base station (BS) in a non-terrestrial network (NTN), the BS comprising: a transceiver; and a processor operably coupled to the transceiver, the processor configured to: generate a system information block (SIB) comprising neighboring cell information of a first neighboring cell and first timing information associated with the first neighboring cell, and transmit the SIB to a user equipment (UE), wherein a measurement of the first neighboring cell by the UE is performed before a time indicated by the first timing information, and wherein a cell reselection is performed based on the measurement of the first neighboring cell.

13. The BS of claim 12, wherein: the first timing information is absolute timing information, and the time indicates a timing instance at which a serving cell stops serving a current service area.

14. The BS of claim 12, wherein: the first neighboring cell information comprises a first physical cell identifier (PCI), and the cell reselection is performed on a cell indicated by the first PCI.

15. The BS of claim 12, wherein: the processor is further configured to generate the SIB comprising redirection information, and the redirection information comprises a second PCI, second frequency information of a second neighboring cell, and second timing information associated with the second neighboring cell.

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