Timing and availability signaling for feed link switching in non-terrestrial networks

Abstract

In a non-terrestrial network (NTN), a source cell may be configured to determine a first time period associated with a handover of a feed link from the source cell to a target cell. The source cell may be further configured to send a message indicating the handover of the feed link based on the first time period. The message may also indicate a second time period associated with availability of the target cell. A user equipment (UE) may be configured to receive the message indicating the feed link handover from the source cell to the target cell and the second time period associated with availability of the target cell. The UE may establish a connection associated with the target cell based on the message.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Indian Provisional Application Serial No. 202241044925 filed on August 5, 2022, entitled “TIMING AND AVAILABILITYSIGNALLING FOR FEEDER LINK SWITCH OVER IN NON-TERRESTRIAL NETWORKS,” the entire text of which is expressly incorporated herein by reference. Background Art Technical Field

[0003] The present disclosure relates generally to communication systems, and more particularly to signaling between user equipment (UE) and network entities related to timing and location for feeder link switching and UE handover.

[0004] introduction

[0005] Wireless communication systems are widely deployed to provide a variety of telecommunication services, such as telephony, video, data, messaging, and broadcast. Typical wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

[0006] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at city, national, regional, and even global levels. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of the continuous mobile broadband evolution promulgated by the Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with the Internet of Things (IoT)) and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable low latency communications (URLLC). Certain aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. Further improvements to 5G NR technology are needed. In addition, these improvements may also be applicable to other multiple access technologies and telecommunication standards that employ these technologies. Summary of the invention

[0007] The following presents a simplified summary of one or more aspects in order to provide a basic understanding of these aspects. This summary is not an extensive overview of all contemplated aspects, and is neither intended to identify key or important elements of all aspects, nor to describe the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to a more detailed description presented later.

[0008] In a first aspect of the present disclosure, a first method, a first computer-readable medium, and a first device are provided. The first device may be a user equipment (UE) or a component thereof. The first device may be configured to receive a message indicating a feeder link switch from a source NTN entity to a target NTN entity and a time period associated with the switch in a non-terrestrial network (NTN). The first device may be further configured to establish a connection associated with the target NTN entity based on the time period.

[0009] In a second aspect of the present disclosure, a second method, a second computer-readable medium, and a second device are provided. The second device may be a source NTN entity or a component thereof. The second device may be configured to determine a first time period associated with a switch of a feeder link from the source NTN entity to a target NTN entity. The second device may be further configured to send a message indicating the switch of the feeder link based on the first time period, the message also indicating a second time period associated with the availability of the target NTN entity.

[0010] In a third aspect of the present disclosure, a third method, a third computer-readable medium, and a third device are provided. The third device may be a target NTN entity or a component thereof. The third device may be configured to obtain the feeder link in a first time period based on a switch of the feeder link from the source NTN entity. The third device may be further configured to establish a corresponding connection with each UE in a group of UEs connected to the source NTN entity in the first time period based on a second time period indicated to each UE in a group of UEs connected to the source NTN entity in a message from the source NTN entity.

[0011] To achieve the foregoing and related ends, one or more aspects include the features fully described below and particularly pointed out in the claims. The following description and the accompanying drawings set forth in detail some illustrative features of one or more aspects. However, these features are merely indicative of some of the various ways in which the principles of the various aspects may be employed, and this specification is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a diagram illustrating an example of a wireless communication system and an access network.

[0013] Figure 2Ais a diagram illustrating an example of a first frame according to various aspects of the present disclosure.

[0014] Figure 2B is a diagram illustrating an example of downlink channels within a subframe according to various aspects of the present disclosure.

[0015] Figure 2C is a diagram illustrating an example of a second frame according to various aspects of the present disclosure.

[0016] Figure 2D is a diagram illustrating an example of uplink channels within a subframe according to various aspects of the present disclosure.

[0017] Figure 3 is a diagram illustrating an example of a base station and a user equipment (UE) in an access network.

[0018] Figure 4 is a diagram illustrating an example of switching of a feeder link in a non-terrestrial network (NTN).

[0019] Figure 5 is a diagram illustrating an example of hard switching of a feeder link in an NTN.

[0020] Figure 6 is a diagram illustrating an example of soft switching of a feeder link in an NTN.

[0021] Figure 7 is a call flow diagram illustrating an example of connection establishment by a UE after feeder link switching in an NTN.

[0022] Figure 8 is a call flow diagram illustrating an example of connection release with redirection for a UE for feeder link handover in an NTN.

[0023] Fig. 9 is a diagram illustrating an example of redirection information included in a Radio Resource Control (RRC) Connection Release message.

[0024] Fig.10 is a flow chart illustrating an example method at a UE for connection establishment after feeder link switching in an NTN.

[0025] Fig.11 is a flow chart illustrating an example method at a source NTN entity for providing connection establishment information to a group of UEs prior to a radio link failure caused by a feeder link switch in the NTN.

[0026] Fig.12 is a flow chart illustrating an example method at a target NTN entity for establishing a respective connection with each UE in a group of UEs upon feeder link switching in an NTN.

[0027] Fig.13 is a diagram illustrating an example of a hardware implementation for an example apparatus.

[0028] Fig.14 is a diagram illustrating another example of a hardware implementation for another example apparatus.

[0029] Fig.15 is a diagram illustrating another example of a hardware implementation for another example apparatus. DETAILED DESCRIPTION

[0030] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of various configurations and is not intended to represent the only configuration with which the concepts described herein can be practiced. In order to provide a thorough understanding of the various concepts, the specific embodiments include specific details. However, the concepts and related aspects described in this disclosure can be implemented in the absence of some or all of such specific details. In some instances, well-known structures, components, etc. are shown in block diagram form to avoid blurring such concepts.

[0031] Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether these elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0032] As an example, an element, or any part of an element, or any combination of elements, may be implemented as a "processing system" that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on chip (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gate logic components, discrete hardware circuits, and other suitable hardware configured to perform various functionalities described throughout the present disclosure. One or more processors in a processing system may execute software. Software should be broadly interpreted as meaning instructions, instruction sets, computer executable codes, code segments, program codes, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether it is described in software, firmware, middleware, microcode, hardware description languages, or other terms.

[0033] Therefore, in one or more example embodiments, the described functions can be implemented with hardware, software or any combination thereof. If implemented in software, each function can be stored or encoded on a computer-readable medium as one or more instructions or computer executable code. Computer-readable media include computer storage media. Storage media can be any available medium that can be accessed by a computer. As an example and not limitation, such computer-readable media can include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage device, magnetic disk storage device, other magnetic storage devices, a combination of computer-readable media of the above type, or any other medium that can be used to store instructions or data structure forms of computer executable code that can be accessed by a computer.

[0034] Figure 1 1 is a diagram illustrating an example of a wireless communication system and access network 100. The wireless communication system (also referred to as a wireless wide area network (WWAN)) includes a base station 102, a user equipment (UE) 104, an evolved packet core (EPC) 160, and another core network 190 (e.g., a 5G core (5GC)). The base station 102 may include a macro cell (a high-power cellular base station) and / or a small cell (a low-power cellular base station). A macro cell includes a base station. A small cell includes a femto cell, a pico cell, and a micro cell.

[0035] The base station 102 configured for 4G Long Term Evolution (LTE) (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) can interface with the EPC 160 via a first backhaul link 132 (e.g., S1 interface). The base station 102 configured for 5G New Radio (NR) (collectively referred to as Next Generation Radio Access Network (RAN) (NG-RAN)) can interface with the core network 190 via a second backhaul link 134.

[0036] The base station 102 may perform, among other functions, one or more of the following functions: delivery of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, RAN sharing, Multimedia Broadcast Multicast Service (MBMS), subscriber and equipment tracking, RAN Information Management (RIM), paging, positioning, and delivery of warning messages.

[0037] In some aspects, the base stations 102 may communicate with each other directly or indirectly (e.g., via the EPC 160 or the core network 190) via a third backhaul link 136 (e.g., an X2 interface). The first backhaul link 132, the second backhaul link 134, and the third backhaul link 136 may be wired, wireless, or some combination thereof. At least some of the base stations 102 may be configured for integrated access and backhaul (IAB). Accordingly, such base stations may communicate wirelessly with other base stations (and may also be configured for IAB).

[0038] At least some base stations 102 configured for IAB may have a split architecture that includes at least one of a central unit (CU), a distributed unit (DU), a radio unit (RU), a remote radio head (RRH), and / or a remote unit, some or all of which may be co-located or distributed and / or may communicate with each other. In some configurations of such a split architecture, the CU may implement some or all functionality of a radio resource control (RRC) layer, and the DU may implement some or all functionality of a radio link control (RLC) layer.

[0039] Illustratively, some of the base stations 102 configured for IAB may communicate with a DU of an IAB donor node or other parent IAB node (e.g., base station) through a corresponding CU, and further, may communicate with a child IAB node (e.g., other base stations) and / or one or more of the UEs 104 through a corresponding DU. One or more of the base stations 102 configured for IAB may be an IAB donor connected to at least one of the EPC 160 and / or the core network 190 through a CU.

[0040] Through such connections to the EPC 160 and / or the core network 190, the base station 102 operating as an IAB donor may provide a link to the EPC 160 and / or the core network 190 to one or more UEs and / or other IAB nodes that may be directly or indirectly connected to the IAB donor (e.g., separated from the IAB donor by more than one hop). In the context of communicating with the EPC 160 or the core network 190, both the UE and the IAB node may communicate with the DU of the IAB donor. In some additional aspects, one or more base stations 102 may be configured with connectivity in an open RAN (ORAN) and / or a virtualized RAN (VRAN), which may be achieved through at least one corresponding CU, DU, RU, RRH, and / or remote unit.

[0041] Base station 102 can communicate wirelessly with UE 104. Examples of UE 104 include cellular phones, smart phones, session initiation protocol (SIP) phones, laptops, personal digital assistants (PDAs), satellite radios, global positioning systems, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, tablets, smart devices, wearable devices, vehicles, electric meters, gas pumps, large or small kitchen appliances, healthcare equipment, implants, sensors / actuators, displays, or any other similarly functional devices. Some of UE 104 may be referred to as IoT devices (e.g., parking meters, gas pumps, toasters, vehicles, heart monitors, etc.). UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

[0042] Each base station 102 may provide communication coverage for a corresponding geographic coverage area 110 (which may also be referred to as a "cell"). Potentially, two or more geographic coverage areas 110 may at least partially overlap with each other, or one of the geographic coverage areas 110 may contain another of the geographic coverage areas. For example, a small cell 102' may have a coverage area 110' that overlaps with the coverage area 110 of one or more macro base stations 102. A network that includes both small cells and macro cells may be referred to as a heterogeneous network. A heterogeneous network may also include a home evolved Node B (eNB) (HeNB), which may provide services to a restricted group referred to as a closed subscriber group (CSG).

[0043] The communication link 120 between the base station 102 and the UE 104 may include uplink (also known as reverse link) transmission from the UE 104 to the base station 102 and / or downlink (also known as forward link) transmission from the base station 102 to the UE 104. The communication link 120 may use multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming and / or transmit diversity. The wireless link or radio link may be on one or more carriers or component carriers (CCs). The base station 102 and / or the UE 104 may use a spectrum of up to Y MHz (e.g., Y may be equal to or approximately equal to 5, 10, 15, 20, 100, 400, etc.) bandwidth per carrier allocated in a carrier aggregation of up to Yx megahertz (MHz) (e.g., x CCs) for transmission in each direction. These CCs may or may not be adjacent to each other. The allocation of CCs may be asymmetric with respect to downlink and uplink (e.g., more or fewer CCs may be allocated to downlinks than to uplinks).

[0044] A CC may include a primary CC and one or more secondary CCs. A primary CC may be referred to as a primary cell (PCell), and each secondary CC may be referred to as a secondary cell (SCell). When the UE is known to both a base station at the access network level and at least one core network entity (e.g., AMF and / or MME) at the core network level, and the UE may be configured to receive downlink control information in the access network (e.g., the UE may be in an RRC connected state), the PCell may also be referred to as a "serving cell". In some instances where carrier aggregation is configured for a UE, each of the PCell and one or more SCells may be a serving cell.

[0045] Some UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. The D2D communication link 158 may use downlink / uplink WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). The D2D communication may be through a variety of wireless D2D communication systems, such as, for example, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

[0046] The wireless communication system may also include a Wi-Fi access point (AP) 150 that communicates with a Wi-Fi station (STA) 152 via a communication link 154 in, for example, a 5 gigahertz (GHz) unlicensed spectrum. When communicating in the unlicensed spectrum, the STA 152 / AP 150 may perform a clear channel assessment (CCA) to determine whether a channel is available prior to communication.

[0047] The small cell 102' may operate in a licensed and / or unlicensed spectrum. When operating in an unlicensed spectrum, the small cell 102' may employ NR and use the same unlicensed spectrum (e.g., 5 GHz, etc.) as used by the Wi-Fi AP 150. The small cell 102' employing NR in the unlicensed spectrum may improve the coverage of the access network and / or increase the capacity of the access network.

[0048] The electromagnetic spectrum is typically subdivided into various categories, bands, channels, etc. based on frequency / wavelength. In 5GNR, two initial operating bands have been identified as frequency range designations FR1 (410 MHz to 7.125 GHz) and FR2 (24.25 GHz to 52.6 GHz). Frequencies between FR1 and FR2 are typically referred to as mid-band frequencies. Although a portion of FR1 is greater than 6 GHz, FR1 is typically (interchangeably) referred to as the “below 6 GHz” band in various documents and articles. Similar naming issues sometimes arise regarding FR2, although unlike the extremely high frequency (EHF) band (30 GHz–300 GHz) identified by the International Telecommunication Union (ITU) as the “millimeter wave” (or “mmWave” or simply “mmW”) band, FR2 is typically (interchangeably) referred to as “millimeter wave” in various documents and articles.

[0049] In view of the above aspects, unless otherwise specifically stated, for the scope used herein, the terms "below 6 GHz", "below 7 GHz", etc. can broadly represent frequencies that can be less than 6 GHz, frequencies that can be less than 7 GHz, frequencies that can be within FR1, and / or frequencies that can include mid-band frequencies. In addition, unless otherwise specifically stated, for the scope used herein, the terms "millimeter wave" and other similar references can broadly represent frequencies that can include mid-band frequencies, frequencies that can be within FR2, and / or frequencies that can be within the EHF band.

[0050] The base station 102 (whether a small cell 102' or a large cell (e.g., a macro base station)) may include and / or be referred to as an eNB, a gNodeB (gNB), or another type of base station. Some base stations 180 (such as gNBs) may operate in traditional sub-6 GHz spectrum, mmW frequencies, and / or near mmW frequencies to communicate with UEs 104. When such base stations 180 (e.g., gNBs) operate at mmW or near mmW frequencies, the base stations 180 may be referred to as mmW base stations. The (mmW) base stations 180 may utilize beamforming 186 with the UEs 104 to compensate for path loss and short range. The base stations 180 and the UEs 104 may each include multiple antennas (such as antenna elements, antenna panels, and / or antenna arrays) to facilitate beamforming.

[0051] The base station 180 may transmit beamformed signals to the UE 104 in one or more transmit directions 182. The UE 104 may receive beamformed signals from the base station 180 in one or more receive directions 184. The UE 104 may also transmit beamformed signals to the base station 180 in one or more transmit directions. The base station 180 may receive beamformed signals from the UE 104 in one or more receive directions. One or both of the base station 180 and / or the UE 104 may perform beam training to determine the best receive and / or transmit direction for one or both of the base station 180 and / or the UE 104. The transmit direction and receive direction of the base station 180 may be the same or different. The transmit direction and receive direction of the UE 104 may be the same or different.

[0052] In various aspects, one or more of the base stations 102 / 180 may include and / or be referred to as a gNB, a Node B, an eNB, an access point, a transceiver base station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit receive point (TRP), or some other suitable term. In addition, the terms "network node" and / or "network entity" may cover one or more of the base stations 102 / 180.

[0053] In some aspects, one or more of the base stations 102 / 180 may be connected to the EPC 160 and may provide one or more of the UEs 104 with a corresponding access point to the EPC 160. The EPC 160 may include a mobility management entity (MME) 162, other MMEs 164, a serving gateway 166, an MBMS gateway 168, a broadcast multicast service center (BM-SC) 170, and a packet data network (PDN) gateway 172. The MME 162 may communicate with a home subscriber server (HSS) 174. The MME 162 is a control node that handles signaling between the UE 104 and the EPC 160. In general, the MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are delivered through the serving gateway 166, which is connected to the PDN gateway 172. The PDN gateway 172 provides UE IP address allocation and other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176. The IP Services 176 may include the Internet, an Intranet, an IP Multimedia Subsystem (IMS), a Packet Switched (PS) Streaming Service, and / or other IP Services. The BM-SC 170 may provide functionality for MBMS user service configuration and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmissions, may be used to authorize and initiate MBMS bearer services in a public land mobile network (PLMN), and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to allocate MBMS services to base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area of ​​a broadcast specific service, and may be responsible for session management (start / stop) and for collecting eMBMS related charging information.

[0054] In some other aspects, one or more of the base stations 102 / 180 may be connected to the core network 190 and may provide one or more of the UEs 104 with corresponding access points to the core network 190. The core network 190 may include an access and mobility management function (AMF) 192, other AMFs 193, a session management function (SMF) 194, and a user plane function (UPF) 195. The AMF 192 may communicate with a unified data management (UDM) 196. The AMF 192 is a control node that handles signaling between the UE 104 and the core network 190. Typically, the AMF 192 provides quality of service (QoS) flows and session management. All user IP packets are delivered through the UPF 195. The UPF 195 provides UE IP address allocation and other functions. The UPF 195 is connected to an IP service 197. The IP service 197 may include the Internet, an intranet, an IMS, a PS streaming service, and / or other IP services.

[0055] In certain aspects of the present disclosure, the wireless communication system and access network 100 may include a non-terrestrial network (NTN). Using the NTN, one or more of the base stations 102 / 180 may be connected to a gateway, which may communicate with the NTN payload. For example, the NTN payload may be implemented via a satellite. The NTN payload may provide a feeder link to the gateway connected to the base station 102 / 180, and may provide some or all of the connectivity and services available through the base station 102 / 180 to the NTN payload via the feeder link. The NTN entity may include any system or device configured to be connected to or connected through the NTN, such as a base station and / or a gateway. For example, in one aspect, when the UE 104 is handed over to the target NTN entity (such as the base station 102' / 180'), the base station 102 / 180 communicating with the UE 104 may be the source NTN entity.

[0056] In certain aspects, the UE 104 may be configured to receive a message (198) in the NTN indicating a feeder link switch from the source base station 102 / 180 to the target base station 102' / 180' and a time period associated with the switch. In some aspects, the message (198) may also indicate that the feeder link switch is associated with a radio link failure or radio link interruption that the source base station 102 / 180 may experience (e.g., the feeder link switch may be experienced contemporaneously). The UE 104 may establish a connection associated with the target base station 102' / 180' based on the message (198). For example, the UE 104 may establish a connection associated with the target base station 102' / 180' based on the time period associated with the switch indicated by the message (198). In some aspects, the message (198) may also indicate information identifying the target base station 102' / 180' and / or a time period that the target base station 102' / 180' may be used to establish a connection.

[0057] The source base station 102 / 180 may be configured to determine a first time period associated with a switch of a feeder link from the source base station 102 / 180 to the target base station 102' / 180'. The source base station 102 / 180 may be further configured to send (e.g., broadcast) a message (198) indicating the switch of the feeder link based on the first time period. The message (198) may also indicate a second time period associated with the availability of the target base station 102' / 180'. In some aspects, the message (198) may also indicate that the feeder link switch is associated with a radio link failure or radio link interruption that the source base station 102 / 180 may experience (e.g., the feeder link switch may be experienced contemporaneously). The UE 104 may establish a connection associated with the target base station 102' / 180' based on the message (198). For example, the UE 104 may establish a connection associated with the target base station 102' / 180' based on the time period associated with the switch indicated by the message (198). In some aspects, the message (198) may also indicate information identifying the target base station 102' / 180' and / or a time period during which the target base station 102' / 180' may be available to establish a connection.

[0058] The target base station 102' / 180' may be configured to obtain the feeder link in a first time period based on the switching of the feeder link from the source base station 102 / 180. The target base station 102' / 180' may be further configured to establish a corresponding connection with the UE 104 connected to the same source base station 102 / 180 in the first time period based on the second time period indicated to each UE in a group of UEs in a message (198) from the source base station 102 / 180.

[0059] In some aspects, the target base station 102' / 180' or the NTN control function may notify the source base station 102 / 180 of the switch of the feeder link from the source base station 102 / 180 to the target base station 102' / 180', the first time period during which the switch will occur, and / or whether the feeder link switch is a hard handoff or a soft handoff. In some aspects, the target base station 102' / 180' or the NTN control function may notify the source base station 102 / 180 of a second time period associated with the availability of the target base station 102' / 180'. In some aspects, the target base station 102' / 180' or the NTN control function may notify the source base station 102 / 180 of information identifying the target base station 102' / 180'.

[0060] Although the present disclosure may focus on 5G NR, the concepts and aspects described herein may be applicable to other similar areas such as LTE, Advanced LTE (LTE-A), Code Division Multiple Access (CDMA), Global System for Mobile Communications (GSM), and / or other wireless / radio access technologies.

[0061] Figure 2Ais a diagram illustrating an example of a first subframe 200 within a 5G NR frame structure. Figure 2B is a diagram illustrating an example of a downlink channel within a 5G NR subframe 230. Figure 2C is a diagram illustrating an example of a second subframe 250 within a 5G NR frame structure. Figure 2D is a diagram illustrating an example of an uplink channel within a 5G NR subframe 280. The 5G NR frame structure can be frequency division duplex (FDD), where for a particular set of subcarriers (carrier system bandwidth), subframes within the set of subcarriers are dedicated to either downlink or uplink; or can be time division duplex (TDD), where for a particular set of subcarriers (carrier system bandwidth), subframes within the set of subcarriers are dedicated to both downlink and uplink. Figure 2A , Figure 2C In the example provided, the 5G NR frame structure is assumed to be TDD, where subframe 4 is configured with slot format 28 (mostly downlink) and subframe 3 is configured with slot format 34 (mostly uplink), where D is downlink, U is uplink, and F is flexible between downlink / uplink. Although subframes 3 and 4 are shown with slot formats 34 and 28, respectively, any particular subframe can be configured with any of the various available slot formats 0-61. Slot formats 0 and 1 are full downlink and full uplink, respectively. Other slot formats 2-61 include a mix of downlink, uplink and flexible symbols. The UE is configured with a slot format (dynamically configured through downlink control information (DCI) or semi-statically / statically configured through RRC signaling) through the received slot format indicator (SFI). Note that the following description also applies to the 5G NR frame structure as TDD.

[0062] Other wireless communication technologies may have different frame structures and / or different channels. For example, a 10 millisecond (ms) frame may be divided into 10 equally sized subframes (1 ms). Each subframe may include one or more time slots. A subframe may also include a microslot, which may include 7, 4, or 2 symbols. Each time slot may contain 7 or 14 symbols, depending on the time slot configuration. For time slot configuration 0, each time slot may include 14 symbols, and for time slot configuration 1, each time slot may include 7 symbols. The symbols on the downlink may be cyclic prefix (CP) orthogonal frequency division multiplexing (OFDM) (CP-OFDM) symbols. The symbols on the uplink may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also known as single carrier frequency division multiple access (SC-FDMA) symbols) (for power-limited scenarios; limited to single stream transmission). The number of time slots in a subframe is based on the time slot configuration and parameter set. For slot configuration 0, different parameter sets μ0 to 4 allow 1, 2, 4, 8, and 16 slots per subframe, respectively. For slot configuration 1, different parameter sets 0 to 2 allow 2, 4, and 8 slots per subframe, respectively. Thus, for slot configuration 0 and parameter set μ, there are 14 symbols per slot and 2 per subframe. μ time slots. The subcarrier spacing and symbol length / duration are functions of the parameter set. The subcarrier spacing can be equal to 2 μ *15 kilohertz (kHz), where μ is parameter set 0 to 4. Therefore, the subcarrier spacing for parameter set μ=0 is 15 kHz, and the subcarrier spacing for parameter set μ=4 is 240 kHz. The symbol length / duration is inversely related to the subcarrier spacing. FIG. 2A to FIG. 2D An example is provided for slot configuration 0 with 14 symbols per slot and parameter set μ=2 with 4 slots per subframe. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 microseconds (μs). Within a set of frames, there may be one or more different bandwidth parts (BWPs) that are frequency-division multiplexed (see Figure 2B ). Each BWP can have a specific set of parameters.

[0063] A resource grid may be used to represent the frame structure. Each slot includes a resource block (RB) (also referred to as a physical RB (PRB)) extending over 12 consecutive subcarriers. The resource grid is divided into a number of resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0064] like Figure 2AAs illustrated, some REs carry at least one pilot signal for the UE, such as a reference signal (RS). Broadly speaking, RSs may be used for beam training and management, tracking and positioning, channel estimation, and / or other such purposes. In some configurations, the RSs may include at least one demodulation RS (DM-RS) (indicated as R for a particular configuration) for channel estimation at the UE. x , where 100x is the port number, but other DM-RS configurations are possible) and / or at least one channel state information (CSI) RS (CSI-RS). In some other configurations, the RS may additionally or alternatively include at least one beam measurement (or management) RS (BRS), at least one beam refinement RS (BRRS) and / or at least one phase tracking RS (PT-RS).

[0065] Figure 2B Examples of various downlink channels within a subframe of a frame are illustrated. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs), each CCE includes nine RE groups (REGs), and each REG includes four consecutive REs in an OFDM symbol. The PDCCH within one BWP may be referred to as a control resource set (CORESET). Additional BWPs may be located at higher and / or lower frequencies across the channel bandwidth. The primary synchronization signal (PSS) may be within symbol 2 of a particular subframe of a frame. UEs (such as Figure 1 The PSS may be used by UE 104 to determine subframe / symbol timing and physical layer identification. The secondary synchronization signal (SSS) may be in symbol 4 of a particular subframe of a frame. Figure 1 The UE 104) can use the SSS to determine the physical layer cell identity group number and the radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine the physical cell identifier (PCI). Based on the PCI, the UE can determine the location of the aforementioned DM-RS. The physical broadcast channel (PBCH) carrying the master information block (MIB) can be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block (also referred to as an SS block (SSB)). The MIB provides the system frame number (SFN) and the number of RBs in the system bandwidth. The physical downlink shared channel (PDSCH) carries user data, broadcast system information such as system information blocks (SIBs) that are not sent through the PBCH, and paging messages.

[0066] like Figure 2CAs illustrated, some of the REs carry DM-RS (indicated as R for a particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE may send a DM-RS for a physical uplink control channel (PUCCH) and a DM-RS for a physical uplink shared channel (PUSCH). The PUSCH DM-RS may be sent in the first or first two symbols of the PUSCH. Depending on whether a short PUCCH or a long PUCCH is sent and depending on the specific PUCCH format used, the PUCCH DM-RS may be sent in different configurations. The UE may send a sounding reference signal (SRS). The SRS may be sent in the last symbol of a subframe. The SRS may have a comb structure, and the UE may send the SRS on one of the teeth of the comb. The SRS may be used by the base station for channel quality estimation to enable frequency-dependent scheduling on the uplink.

[0067] Figure 2D Examples of various uplink channels within a subframe of a frame are illustrated. The PUCCH may be located at a position as indicated in one configuration. The PUCCH carries uplink control information (UCI), which may include a scheduling request (SR), a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and hybrid automatic repeat request (HARQ) acknowledgement (ACK) / negative acknowledgement (NACK) feedback. The PUSCH carries data and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0068] Figure 33 is a block diagram of a base station 310 in an access network 300 communicating with a UE 350. In the downlink, IP packets from the EPC 160 may be provided to a controller / processor 375. The controller / processor 375 implements layer 2 (L2) and layer 3 (L3) functionality. The L3 includes an RRC layer, and the L2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, an RLC layer, and a medium access control (MAC) layer. The controller / processor 375 provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with delivery of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0069] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 (L1) functionality associated with various signal processing functions. The L1 including the physical (PHY) layer may include error detection of transport channels, forward error correction (FEC) coding / decoding of transport channels, interleaving, rate matching, mapping onto physical channels, modulation / demodulation of physical channels, and MIMO antenna processing. The TX processor 316 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-order phase shift keying (M-PSK), M-order quadrature amplitude modulation (M-QAM)). The decoded and modulated symbols may then be divided into parallel streams. Subsequently, each stream may be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., a pilot) in the time and / or frequency domain, and then combined using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially pre-coded to generate multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation schemes, as well as for spatial processing. Channel estimates may be derived from reference signals and / or channel state feedback sent by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate a radio frequency (RF) carrier for transmission using a corresponding spatial stream.

[0070] At the UE 350, each receiver 354RX receives a signal through at least one corresponding antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides the information to a receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement L1 functionality associated with various signal processing functions. The RX processor 356 can perform spatial processing on the information to recover any spatial stream destined for the UE 350. If multiple spatial streams are destined for the UE 350, they can be combined into a single OFDM symbol stream by the RX processor 356. The RX processor 356 then converts the OFDM symbol stream from the time domain to the frequency domain using a fast Fourier transform (FFT). The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier and the reference signal are recovered and demodulated by determining the most likely signal constellation point sent by the base station 310. These soft decisions can be based on channel estimates calculated by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally sent on the physical channel by the base station 310. The data and control signals are then provided to a controller / processor 359, which implements L3 and L2 functionality.

[0071] The controller / processor 359 may be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer readable medium. In the uplink, the controller / processor 359 provides demultiplexing between transport channels and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection using an ACK and / or NACK protocol to support HARQ operations.

[0072] Similar to the functionality described in conjunction with downlink transmissions performed by the base station 310, the controller / processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functionality associated with header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functionality associated with delivery of upper layer PDUs, error correction through ARQ, concatenation, segmentation and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0073] The TX processor 368 may use channel estimates derived by the channel estimator 358 from a reference signal or feedback sent by the base station 310 to select appropriate coding and modulation schemes and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via corresponding transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0074] Uplink transmissions are processed at the base station 310 in a manner similar to that described in conjunction with the receiver functionality at the UE 350. Each receiver 318RX receives a signal through at least one corresponding antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

[0075] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer readable medium. In the uplink, the controller / processor 375 provides demultiplexing between transport channels and logical channels, packet reassembly, decryption, header decompression, control signal processing to recover IP packets from the UE 350. The IP packets from the controller / processor 375 may be provided to the EPC 160. The controller / processor 375 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operations.

[0076] In some aspects, at least one of the TX processor 368, the RX processor 356, and the controller / processor 359 may be configured to perform operations related to Figure 1 (198) All aspects of the combination.

[0077] In some other aspects, at least one of the TX processor 316, the RX processor 370, and the controller / processor 375 may be configured to perform operations related to Figure 1 (198) All aspects of the combination.

[0078] Figure 4 is a diagram illustrating an example of feeder link switching in NTN 400. Feeder link switching is a procedure whereby the feeder link is changed from a source NTN Gateway (GW) 406a to a target NTN GW 406b for a specific NTN payload 410. Feeder link switching is a transport network layer procedure.

[0079] Feeder link switching may result in the connection established for the UE being transferred from the source gNB 402a to the target gNB 402b. Both hard feeder link switching and soft feeder link switching are applicable to NTN. Hard switching is a break-before-make switching, while soft switching is a make-before-break switching.

[0080] For soft feeder link switching, the NTN payload 410 can be connected to two or more NTN GWs 406a, 406b during a period of time, and thus, the feeder link 414a through one NTN GW 406a can temporarily overlap with the feeder link 414b through another NTN GW 406b. This temporary overlap can shorten or eliminate the duration of the UE's lack of connectivity or radio link.

[0081] For hard feeder link switching, the NTN payload 410 can only be connected to one NTN GW at a time. Therefore, the UE may experience a radio link failure or interruption during the transition between the feeder links 414a, 414b.

[0082] The NTN control function may determine a moment to perform a feeder link switch between the two gNBs 402a, 402b. For example, a transition threshold 412 may be established, and once the NTN payload 410 reaches the transition threshold 412, the feeder link switch may be performed. The transfer of the context of the affected UE between the source gNB 402a and the target gNB 402b at the feeder link switch may be performed via one of a variety of methods such as an RRC reestablishment procedure, a UE handover, and / or an RRC release procedure including an RRC connection release with redirection. Different gNBs may be implemented differently by the NTN control function and / or configured differently.

[0083] Figure 5 is a diagram illustrating an example of a hard feeder link switch in an NTN 500. The UE 504 may operate on a cell provided by a source gNB 502a because the source gNB 502a may be connected to the NTN via a first GW 506a due to the NTN payload providing a feeder link 514a to the first GW 506a. However, the NTN payload 510 may cross a transition threshold 512, thereby triggering a feeder link switch. In the illustrated aspect, the NTN payload 510 may only be able to maintain one feeder link at a time. Therefore, when the NTN payload 510 crosses the transition threshold 512 during a time period T1, the feeder link 514a provided to the first GW 506a may be terminated. The NTN payload 510 may switch to providing a feeder link 514b to a second GW 506b. During this switch, the UE 504 has not yet been handed over to the target gNB 502b or synchronized with the target gNB. Therefore, when the feeder link 514a to the first GW 506a is switched to the feeder link 514b to the second GW 506b, the UE 504 experiences a radio link failure (RLF) or radio link interruption.

[0084] During time period T2, the NTN payload 510 may have crossed the transition threshold 512, and a feeder link 514b may be established to the second GW 506b. Thus, the target gNB 502b is available for use by the UE 504. In some aspects, the UE 504 may be handed over from the source gNB 502a to the target gNB 502b via a conditional handover procedure, for example, based on a conditional handover configuration provided by the source gNB 502a to the UE 504. In some other aspects, the UE 504 may reestablish the connection, such as by performing an RRC connection reestablishment procedure with the target gNB 502b. For example, the UE 504 may send an RRC connection reestablishment request to the target gNB 502b, and the target gNB 502b may respond with an RRC connection reestablishment message that configures the RRC connection reestablishment with the UE 504. Based on the RRC connection reestablishment, the UE 504 may send an RRC connection reestablishment complete message to the target gNB 502b.

[0085] Figure 6 6 is a diagram illustrating an example of soft feeder link switching in NTN 600. UE 604 may operate on a cell provided by source gNB 602a because source gNB 602a may be connected to NTN through first GW 606a because NTN payload is providing feeder link 614a to first GW 606a in time period T1. 1.5 , the NTN payload 610 may cross the transition threshold 612, thereby triggering a feeder link switch. In the illustrated aspect, the NTN payload 610 is capable of maintaining at least two feeder links simultaneously. 1.5 When the transition threshold 612 is crossed, the feeder link 614a provided to the first GW 606a may remain active while establishing a feeder link 614b with the target gNB 602b. During this switch, the UE 604 may be handed over to the target gNB 602b, which may prevent the UE 604 from experiencing RLF or radio link interruption when the feeder link 614a to the first GW 606a is switched to the feeder link 614b to the second GW 606b.

[0086] In time period T2, the NTN payload 610 may have crossed the transition threshold 612, and a feeder link 614b may be established to the second GW 606b. 1.5 may have already been handed over, so that UE 604 may continue radio link communications during time period T2, for example, so that the feeder link switching is largely transparent to UE 604.

[0087] In some aspects, the UE 604 may be handed over from the source gNB 602a to the target gNB 602b via a conditional handover procedure, e.g., based on a conditional handover configuration provided by the source gNB 602a to the UE 604. In some other aspects, the UE 604 may be handed over from the source gNB 602a to the target gNB 602b via a blind handover procedure, e.g., in which the UE 604 does not provide any measurements for the handover procedure to the source gNB 602a.

[0088] Figure 7 is a call flow diagram illustrating an example operational flow 700 for connection establishment by a UE 704 after a feeder link handover 730 in an NTN. In some aspects, the UE 704 may be an Internet of Things (IoT) UE or other IoT device.

[0089] Prior to time period T1, UE 704 may be connected to source gNB 702a and may therefore be operating in an RRC connected state with source gNB 702a. However, source gNB 702a may determine that a feeder link switch is about to occur. Therefore, source gNB 702a may send (e.g., broadcast) SIB 724 indicating that a feeder link switch is about to occur. Source gNB 702a may also indicate the type of feeder link switch (e.g., hard switch or soft switch) and / or the time period T1 during which the feeder link switch will occur. Source gNB 702a may also send (e.g., broadcast) an indication 726 of the target gNB 702b that will be next available after the feeder link switch and / or the time period T1+x during which the target gNB 702b will be available after the feeder link switch. In some aspects, indication 726 may be included in SIB 724. In some aspects, indication 726 may be sent over the Uu interface.

[0090] In some aspects, the SIB may be SIB19. For example, SIB19 may be used in 5G NR NTN. In some other aspects, the SIB may be SIB3. For example, SIB3 may be used in LTE networks, such as for NTN IoT.

[0091] During the time period T1 of the feeder link switching, the source gNB 702a may be configured to send the corresponding context associated with UE704 (and other UEs that have a connection with the source gNB 702a during the time period) to the target gNB 702b. In some aspects, the source gNB 702a may send the UE context via an Xn interface. For example, the source gNB 702a may use the XnAP control protocol to send the UE context. In some other aspects, the source gNB 702a may send the UE context (x) via an X2 interface (e.g., for NTN IoT in LTE).

[0092] In some aspects, the feeder link switch 730 is a hard switch. In some such aspects, the NTN payload may terminate the feeder link to the source gNB 702a in time period T1. The feeder link switch 730 may occur, and therefore, the feeder link with the source gNB 702a may be disconnected, and the feeder link with the target gNB 702b may be established. In some aspects, the UE 704 may be handed over from the source gNB 702a to the target gNB 702b. The handover may be a conditional handover, which may be initiated by measurements performed by the UE 704. The source gNB 702a may provide a conditional handover configuration to the UE 704 prior to time period T1. The conditional handover configuration may configure at least one of the type of measurement and / or the threshold that may trigger the handover. In another example, the RRC connection between the UE 704 and the source gNB 702a may be terminated.

[0093] In some other aspects, the feeder link handover 730 is a soft handover. In some such aspects, the NTN payload may contemporaneously maintain a feeder link toward the source gNB 702a and a feeder link toward the target gNB 702b. In some aspects, during this period, the UE 704 may handover from the source gNB 702a to the target gNB 702b. In one example, the handover may be a conditional handover, which may be initiated by measurements performed by the UE 704. The source gNB 702a may provide a conditional handover configuration to the UE 704, which may configure at least one of the type of measurement and / or thresholds that may trigger the handover. In another example, the handover may be a blind handover, which may not be triggered by UE measurements.

[0094] Due to the feeder link switch 730, the UE 704 may experience RLF or radio link interruption with the source gNB 702a. In some instances, the UE 704 may be configured to report the RLF to the network. However, in the case of the feeder link switch 730, the RLF is expected and the radio link with the target gNB 702b may be established shortly thereafter. Therefore, in some aspects, the UE 704 may be configured to avoid reporting RLF associated with the source gNB 702a, for example based on the SIB 724 indicating the switch 730 (the switch 730 is the cause of the RLF). In some aspects, to avoid reporting RLF, the UE 704 may be configured to detect RLF associated with the source gNB 702a, but may be configured to avoid reporting RLF (e.g., based on the received SIB 724 indicating the switch 730). In some other aspects, to avoid reporting RLF, the UE 704 may be configured (e.g., based on a received SIB 724 indicating the switch 730) to avoid detecting RLF with the source gNB 702a during a time period occurring concurrently with time period T1 of the feeder link switch 730. In aspects where the switch 730 is a soft switch 730, the UE 704 may move to the target gNB 702b before the RLF occurs.

[0095] In some aspects, at time period T1+x, the UE 704 may be configured to trigger a handover procedure based on the feeder link switch 730. The handover procedure may be a conditional handover procedure, which may be based on measurements performed by the UE 704 at a particular time T1+x. For example, the source gNB 702a may send a configuration for a conditional handover to the UE 704, which may indicate measurements to be performed by the UE 704 at a particular time T1+x and / or measurement thresholds to be reported by the UE 704 to trigger the handover. In some other aspects where the handover 730 is a soft handover, the handover procedure may be a blind handover procedure that is not based on measurements and reports from the UE 704.

[0096] In some aspects, the UE 704 may be further configured to identify the target gNB 702b based on an indication 726 associated with the availability of the target gNB 702b. For example, the UE 704 may decode the received SIB 724 to obtain an indication 726 of one or more of: a cell identifier (ID) of the target gNB 702b (e.g., PCI), a carrier frequency of the target gNB 702b, an ARFCN of the target gNB 702b, a subcarrier spacing of SSBs transmitted by the target gNB 702b, and / or an SSB measurement and timing configuration associated with the target gNB 702b.

[0097] During the time period T1+x that the target gNB 702b becomes available, the UE 704 may be configured to establish a connection associated with the target gNB 702b. For example, the UE 704 may synchronize or attach to the target gNB 702b. The UE 704 may establish a connection with the target gNB 702b based on the time period T1+x that the target gNB 702b is available after the feeder link switch 730, which may be indicated in the received indication 726 (e.g., included in the SIB 724).

[0098] In some aspects, the UE 704 may establish a connection associated with the target gNB 702b by reestablishing an RRC connection with the target gNB 702b. For example, the UE 704 may be configured to send an RRC connection reestablishment request 734 to the target gNB 702b based on a time period T1+x, and the UE 704 may be configured to reestablish the RRC connection through the target gNB 702b based on the RRC connection reestablishment request. Based on receiving the RRC connection reestablishment request 734, the target gNB 702b may send an RRC connection reestablishment complete message to the UE 704, for example, so that radio resources can be allocated to the UE 704 through the target gNB 702b.

[0099] In some other aspects, the UE 704 may establish a connection associated with the target gNB 702b by attaching to the target gNB 702b. For example, the UE 704 may synchronize with the target gNB 702b, such as by acquiring a MIB and / or one or more SIBs transmitted by the target gNB 702b, by performing a random access channel (RACH) procedure with the target gNB 702b, and the like.

[0100] Figure 8 is a call flow diagram illustrating an example operational flow 800 of connection release with redirection for a UE 804 for feeder link switching 830 in an NTN. In some aspects, the UE 804 may be an Internet of Things (IoT) UE or other IoT device.

[0101] Prior to time period T1, UE 804 may be connected to source gNB 802a and may therefore be operating in an RRC connected state with source gNB 802a. Source gNB 802a may be notified of the feeder link switch 730 at time period T1 (e.g., by the NTN control function). In some aspects, source gNB 802a may also be notified of the type of switch (e.g., hard or soft) and / or the next available target gNB 802b after the switch 830 at time period T1.

[0102] Based on the notification (e.g., from the NTN control function), the source gNB 802a may send an RRC connection release message 824 to the UE 804 in time period T1. The RRC connection release message 824 may include redirection information. For example, the source gNB 802a may be notified of the (hard) handover of the feeder link and the target gNB 802b that will be available after the feeder link handover 830 in time period T1. The source gNB 802a may include information indicating the time period T1+x during which the target gNB 802b and the target gNB 802b will become available, which may be an offset x from a reference time period T1 during which the feeder link handover 830 occurs.

[0103] Fig. 9 is a diagram illustrating an example portion of an RRC connection release message 900 including redirection information 910. The redirection information 910 may indicate an ARFCN 912 of a target gNB 802b, a subcarrier spacing of an SSB 914 transmitted by the target gNB 802b, and / or an SSB measurement and timing (smtc) configuration 916 associated with the target gNB 802b, some or all of which may be used by a UE 804 to identify the target gNB 802b and / or operate on a cell provided by the target gNB 802b. The redirection information 910 may also indicate an availability time 920 at which the target gNB 802b is available after a feeder link switch 830. The availability time 920 may be indicated as a reference time to which an offset x may be added (e.g., feeder link switch time period T1), or the availability time 920 may be indicated as an absolute or clock time period T1+x at which the target gNB 802b will be available.

[0104] Reference again Figure 8 , at time T1, the NTN payload may switch the feeder link from the source gNB 802a to the target gNB 702b. In some aspects, the switch 830 is a hard switch. In some such aspects, the NTN payload may terminate the feeder link to the source gNB 802a at time period T1 and establish a feeder link with the target gNB 802b.

[0105] The UE 804 may be configured to identify the target gNB 802b based on the redirection information 910 associated with the target gNB 802b included in the RRC connection release message 824. For example, the UE 804 may decode the received RRC connection release message 824 to obtain information indicating one or more of: a cell ID (e.g., PCI) of the target gNB 802b, a carrier frequency of the target gNB 802b, an ARFCN of the target gNB 802b, a subcarrier spacing of an SSB sent by the target gNB 802b, and / or an SSB measurement and timing configuration associated with the target gNB 802b. The UE 804 may tune receiver circuitry (e.g., circuitry of an RF front end and / or circuitry of a PHY layer) to the carrier frequency and / or ARFCN of the target gNB 802b.

[0106] During the availability time period T1+x indicated in the redirection information 910, the UE 804 may be configured to establish a connection associated with the target gNB 802b. In some aspects, the UE 804 may establish a connection associated with the target gNB 802b by attaching or synchronizing 832 to the target gNB 802b. For example, the UE 804 may synchronize 832 with the target gNB 802b by acquiring a MIB and / or one or more SIBs transmitted by the target gNB 802b. In another example, the UE 804 may synchronize 832 with the target gNB 802b by performing a RACH procedure with the target gNB 802b.

[0107] In some aspects, the UE 804 may establish a connection with the target gNB 802b based on the redirection information 910 included in the RRC connection release message 824. For example, the UE 804 may decode and / or parse the redirection information 910 to obtain the carrier frequency, ARFCN, SSB subcarrier spacing, SSB measurement and timing configuration, and / or other information that may be used alone or with other information to identify the target gNB 802b and / or operate on a cell provided by the target gNB 802b.

[0108] Fig.10 1 is a flow chart of a method 1000 of wireless communication. The method 1000 may be performed by or at a UE (e.g., UE 104, 350), another wireless communication device, or one or more components thereof. According to various aspects, one or more of the illustrated blocks of the method 1000 may be omitted, swapped, and / or performed concurrently.

[0109] At operation 1002, the UE may be configured to receive a message in the NTN indicating a feeder link switch from a source NTN entity to a target NTN entity and a time period associated with the switch. In some aspects, the message includes one of a SIB or an RRC connection release message. In some aspects, the SIB includes one of SIB3 or SIB19. In some aspects, the RRC connection release message includes redirection information, and the connection may be further established based on the redirection information.

[0110] exist Figure 7 In the context of , operation 1002 may be illustrated by UE 704 receiving SIB 724 in NTN indicating switch 730. In some aspects, SIB 724 may also indicate that feeder link switch 730 in time period T1 is a hard switch (e.g., as described above with respect to Figure 5 ) or soft switching (e.g., as described above with respect to Figure 6 ). In addition, the UE 704 may receive an indication 726 of the availability of the target gNB 702b after the handover 730. The UE 704 may receive the SIB 724 and / or the availability 726 of the target gNB 702b before the time period T1 in which the handover 730 occurs. In some aspects, the availability 726 of the target gNB 702b may be indicated in the SIB 724. In some aspects, the availability 726 of the target gNB 702b may be indicated to the UE 704 as a time period T1+x offset from the handover time period T1. In some other aspects, the availability 726 of the target gNB 702b may be indicated to the UE 704 as or using information identifying the target gNB 702b, such as a cell ID (e.g., PCI), a carrier frequency, an ARFCN, and / or other information that may be used to locate the target gNB 702b and / or synchronize with the target gNB.

[0111] exist Figure 8 In the context of , operation 1002 may be illustrated by UE 804 receiving an RRC connection release message 824 in the NTN. UE 804 may receive the RRC connection release message 824 before a time period T1 at which a handover from source gNB 802a to target gNB 802b occurs. The RRC connection release message 824 may include redirection information identifying the target gNB 802b. For example, in Fig. 9 In the context of, the RRC connection release message 824 may include redirection information 910 of the target gNB 802b, and the redirection information 910 may indicate the ARFCN 912 of the target gNB 802b to which the UE 804 is to attach.

[0112] In addition, the RRC Connection Release message 824 may indicate a time at which the target gNB 802b will be available for handover of the UE 804 from the source gNB 802a and / or for synchronization 830 of the UE 804 with the target gNB 802b (such as by receiving a MIB and / or one or more SIBs, by performing a RACH procedure, etc.). Fig. 9 In the context of, the RRC connection release message 824 may include redirection information 910, which includes an available time field indicating the target gNB availability time 920, which may be indicated as a reference time to which the offset x can be applied (e.g., the feeder link switching time period T1).

[0113] At operation 1004, in some optional aspects, the UE may be configured to identify the target NTN entity based on information associated with the target NTN entity included in the message. For example, the UE may decode the received message to obtain information indicating one or more of the following: a carrier frequency of the target NTN entity, an ARFCN of the target NTN entity, a subcarrier spacing of an SSB sent by the target NTN entity, and / or an SSB measurement and timing configuration associated with the target NTN entity. The UE may tune a receiver circuit (e.g., circuitry of an RF front end and / or circuitry of a PHY layer) to the carrier frequency and / or ARFCN of the target NTN entity.

[0114] exist Figure 7 In the context of , operation 1002 may be illustrated by UE 704 identifying target gNB 702b based on information included in SIB 724. Figure 8 In the context of , operation 1002 may be illustrated by UE 804 identifying target gNB 802b based on redirection information included in RRC connection release message 824. Fig. 9 , for example, the RRC connection release message 824 may include redirection information 910 indicating an ARFCN 912, which the UE 804 can use to tune the receiver circuit to the carrier frequency of the target gNB 802b.

[0115] At operation 1006, in some other optional aspects, the UE may be configured to avoid reporting RLF associated with the source NTN entity based on the message. The message may indicate to the UE that a feeder link switch is about to occur. If the feeder link switch is a hard switch in time period T1, the UE may lose connectivity to the NTN (temporarily) in time period T1. In one example, the UE may avoid reporting RLF based on an indication that the switch is associated with RLF. In some aspects, to avoid reporting RLF, the UE may be configured to detect RLF associated with the source NTN entity, but may be configured to avoid reporting RLF (e.g., based on the received message). In some other aspects, to avoid reporting RLF, the UE may be configured to avoid detecting RLF during a time period that occurs concurrently with time period T1 of the feeder link switch (e.g., based on the received message).

[0116] exist Figure 7 In the context of , operation 1006 may be illustrated by the UE 704 avoiding reporting an RLF that occurs concurrently with a feeder link switch 730. In the event that the radio link to the NTN is unavailable to the UE 704 during a time period T1 due to a (hard) feeder link switch 730, the UE 704 may be configured to avoid reporting an RLF associated with (e.g., caused by) the feeder link switch 730. For example, the UE may be configured to detect an RLF associated with the source gNB 702a, which may be caused by the feeder link switch 730. However, the UE 704 may be configured (e.g., based on the received SIB 724) to avoid sending a report indicating that an RLF was detected (e.g., based on the indication of the time period T1 of the feeder link switch 730 included in the SIB 724). In another example, the UE may be configured (e.g., based on the received SIB 724) to avoid RLF detection during a time period that occurs concurrently with the time period T1 of the feeder link switch 730.

[0117] At operation 1008, the UE may be configured to establish a connection associated with the target NTN entity based on the time period. The UE may establish a connection with the target NTN entity based on a time period T1+x during which the target NTN entity is available after the feeder link switch, which may be indicated in the received message indicating the switch.

[0118] In some aspects, the UE may establish a connection associated with the target NTN entity by reestablishing an RRC connection with the NTN. For example, the UE may be configured to send an RRC connection reestablishment request to the target NTN entity based on a time period (e.g., time period T1+x), and the UE may be configured to reestablish the connection associated with the target NTN entity based on the RRC connection reestablishment request. The UE may receive an RRC connection reestablishment complete message from the target NTN entity, which may indicate that the bearer has been allocated to the UE and the UE is (re)connected with the NTN through the target NTN entity.

[0119] In some other aspects, the UE may establish a connection associated with the target NTN entity by attaching to the target NTN entity. For example, the UE may synchronize with the target NTN entity, such as by acquiring a MIB and / or one or more SIBs sent by the target NTN entity, by performing a RACH procedure with the target NTN entity, etc.

[0120] In some further aspects, the UE may establish a connection associated with the target NTN entity by sending an RRC connection request to the target NTN entity. The UE may receive an RRC connection establishment message from the target NTN entity in response to the RRC connection request. Based on the RRC connection establishment message, the UE may send an RRC connection establishment complete message to the target NTN entity.

[0121] In yet other aspects, the UE may establish a connection associated with the target NTN entity by receiving an RRC connection reconfiguration message from the target NTN entity. The RRC connection reconfiguration message may be used to configure one or more logical, transport and / or physical channels between the UE and the target NTN entity. Additionally or alternatively, the RRC connection reconfiguration message may be used to establish or modify one or more radio bearers of the UE through the target NTN entity.

[0122] In some aspects, the connection may be established further based on information associated with the target NTN entity. For example, the information associated with the target NTN entity may include redirection information included in an RRC connection release message with redirection information. The UE may decode and parse the redirection information to obtain carrier frequency, ARFCN, SSB subcarrier spacing, SSB measurement and timing configuration, and / or other information that may be used alone or in conjunction with other information to identify the target NTN entity and / or operate on a cell provided by the target NTN entity.

[0123] In some aspects, when a configuration associated with a conditional handover of the UE from the source NTN entity to the target NTN entity has been received from the source NTN entity, the UE may further establish a connection associated with the target NTN entity based on the conditional handover. The conditional handover configuration may indicate a set of conditions to be satisfied in order for the UE to initiate a handover procedure from the source NTN entity to the target NTN entity. For example, the configuration may indicate a time period T1 during which a feeder link switch 730 is to occur, which may cause the source NTN entity to become unavailable for connectivity to the UE. Thus, when the UE detects a condition that the clock time (or current time) is equal to the time period T1 (or within a threshold margin of the time period T1), the UE may initiate a conditional handover procedure from the source NTN entity to the target NTN entity.

[0124] exist Figure 7 In the context of , operation 1008 may be illustrated by UE 704 sending an RRC connection reestablishment request 734 during a time period T1+x when target gNB 702b is available after feeder link switching 730. UE 704 may receive an RRC connection reestablishment complete message from target gNB 702b based on request 734.

[0125] exist Figure 8 In the context of , operation 1008 may be illustrated by UE 804 synchronizing 832 to target gNB 802b. In some aspects, UE 804 may obtain MIB and / or SIB from target gNB 802b and / or UE 804 may perform RACH procedures with target gNB 802b to synchronize 832 with target gNB 802b.

[0126] Fig.11 1 is a flow chart of a method 1100 of wireless communication. The method 1100 may be performed by or at a network entity (e.g., base station 102 / 180, 310), another wireless communication device, or one or more components thereof. For example, the method 1100 may be performed by or at a source NTN entity. According to various aspects, one or more of the illustrated blocks of the method 1100 may be omitted, swapped, and / or performed concurrently.

[0127] At operation 1102, the source NTN entity may be configured to determine a first time period associated with a switch of a feeder link from the source NTN entity to a target NTN entity. In some aspects, the source NTN entity may be notified of a time period T1 in which the feeder link switch will occur. For example, the source NTN entity may be notified by a gateway or other similar network entity configured to communicate with the source NTN entity. In some other aspects, the target NTN entity may also be notified that a group of UEs connected to the source NTN entity in time period T1 will be connected to the target NTN entity in another time period T1+x after the feeder link switch. For example, the source NTN entity may be notified of a cell ID (e.g., PCI) of the target NTN entity, a carrier frequency of the target NTN entity, an ARFCN of the target NTN entity, a subcarrier spacing of an SSB sent by the target NTN entity, an smtc configuration associated with the target NTN entity, and / or other redirection information that may be used by a UE to identify the target NTN entity and / or operate on a cell provided by the target NTN entity.

[0128] exist Figure 7 In the context of , operation 1102 may be illustrated by the source gNB 702a determining a time period T1 during which a feeder link switch 730 occurs (or is to occur). Figure 8 In the context of , operation 1102 may be illustrated by the source gNB 802a determining a time period T1 during which a feeder link handover 830 occurs (or is about to occur). For example, the source gNB 802a may be notified of an upcoming (hard) handover of the feeder link during time period T1. The source gNB 802a may also be notified of the next available target gNB 802b.

[0129] At operation 1104, the source NTN entity may be configured to send a message indicating the switching of the feeder link based on the first time period, the message also indicating a second time period associated with the availability of the target NTN entity. In some aspects, the message includes one of a SIB or an RRC connection release message. For example, the SIB may include one of SIB3 or SIB19. In some aspects, the RRC connection release message may include redirection information identifying the target NTN entity. In some aspects, the message also includes an indication that the switching is associated with RLF. Such an indication that the switching is associated with RLF may prevent the UE from reporting an RLF that may occur concurrently with the feeder link switching.

[0130] exist Figure 7 In the context of , operation 1104 may be illustrated by source gNB 702a sending SIB 724. For example, source gNB 702a may broadcast SIB 724 in a cell provided by source gNB 702a.

[0131] exist Figure 8In the context of , operation 1104 may be illustrated by the source gNB 802a sending an RRC connection release message 824. The RRC connection release message 824 may include redirection information. For example, the source gNB 802a may be notified of the (hard) handover of the feeder link and the target gNB 802b that will be available after the feeder link handover 830 in time period T1. The source gNB 802a may include information indicating the time period T1+x during which the target gNB 802b and the target gNB 802b will become available, which may be an offset x from a reference time period T1 during which the feeder link handover 830 occurs.

[0132] refer to Fig. 9 , the redirection information 910 may indicate the ARFCN of the target gNB 802b, the subcarrier spacing of the SSBs sent by the target gNB 802b, and / or the SSB measurement and timing configuration associated with the target gNB 802b, some or all of which may be used by the UE to identify the target gNB 802b and / or operate on a cell provided by the target gNB 802b. The redirection information 910 may also indicate an availability time 920 at which the target gNB 802b is available after the feeder link switch. The availability time may be indicated as a reference time (e.g., feeder link switch time period T1) to which an offset x may be added.

[0133] At 1106, in some optional aspects, the source NTN entity may be configured to send, to the target NTN entity, a corresponding context associated with each UE in a set of UEs that have a connection with the source NTN entity during the first time period. The source NTN entity may send the UE context via an Xn interface. For example, the source NTN entity may send the UE context using an XnAP control protocol.

[0134] exist Figure 7 In the context of , operation 1106 may be illustrated by the source gNB 702a performing a UE context transfer 728. During the UE context transfer 728, the source gNB 702a may send a respective UE context for each of the UEs connected to the source gNB 702a to the target gNB 702b at time period T1 or a time period before time period T1.

[0135] At 1108, in some optional aspects, the source NTN entity may be configured to perform a handover of each UE in a group of UEs to the target NTN entity based on the switching of the feeder link associated with the first time period. For example, the source NTN entity may send a handover request to the target NTN entity, and based on this, the source NTN entity may receive a handover request confirmation from the target NTN entity. The source NTN entity may also send a sequence number (SN) status transfer message to the target NTN entity, for example, after receiving the handover request confirmation. In some aspects, the source NTN entity may be configured to send a configuration associated with a conditional handover to the target NTN entity to at least one UE in the group of UEs, and may hand over the at least one UE in the group of UEs to the target NTN entity based on the configuration.

[0136] exist Figure 7 In the context of , operation 1108 may be illustrated by the source gNB 702a performing a handover of the UE 704 to the target gNB 702b based on the feeder link switch 730 in time period T1. Figure 8 In the context of , operation 1108 may be illustrated by the source gNB 802a performing a handover of the UE 804 to the target gNB 802b based on the feeder link switch 830 in the time period T1.

[0137] In some aspects, the source NTN entity may send an RRC connection release message (e.g., before or during a handover procedure or without performing a handover procedure). The RRC connection release message may be an RRC connection release with a redirection message that includes redirection information associated with the target NTN entity. For example, the source NTN entity may be notified of a (hard or soft) switch of a feeder link at time period T1 and information associated with the target NTN entity that will be available after the feeder link switch. The source NTN entity may include information indicating the target NTN entity, the time period T1, and / or the time period T1+x during which the target NTN entity will become available.

[0138] The redirection information may indicate one or more of the following: a cell ID (e.g., PCI) of the target NTN entity, a carrier frequency of the target NTN entity, an ARFCN of the target NTN entity, a subcarrier spacing of an SSB sent by the target NTN entity, and / or an SSB measurement and timing configuration associated with the target NTN entity, some or all of which may be used by a UE to identify the target NTN entity and / or operate on a cell provided by the target NTN entity. The redirection information may also indicate an availability time available to the target NTN entity after the feeder link switch. The availability time may be indicated as a reference time (e.g., a feeder link switch time period T1) to which an offset x may be added.

[0139] Fig.12 1 is a flow chart of a method 1200 for wireless communication. The method 1200 may be performed by or at a network entity (e.g., base station 102 / 180, 310), another wireless communication device, or one or more components thereof. For example, the method 1200 may be performed by or at a target NTN entity. According to various aspects, one or more of the illustrated blocks may be omitted, swapped, and / or performed concurrently.

[0140] At operation 1202, the target NTN entity may be configured to obtain the feeder link in a first time period based on a handover of the feeder link from the source NTN entity. For example, the target NTN entity may receive information indicating a group of satellites that may supply the feeder link to the target NTN entity. For example, once one of the group of satellites reaches a handover threshold in time period T1, the target NTN entity may connect to the one of the group of satellites.

[0141] exist Figure 4 In the context of , operation 1202 may be illustrated by gNB2 402b obtaining feeder link 414b from NTN payload 410 via GW2 406b. Figure 5 In the context of , operation 1202 may be illustrated by gNB2 502b obtaining feeder link 514b from NTN payload 510 via GW2 506b. Figure 6 In the context of , operation 1202 may be illustrated by gNB2 602b obtaining a second feeder link 614b from the NTN payload 610 via GW2 606b.

[0142] At operation 1204, in some optional aspects, the target NTN entity may receive a corresponding UE context associated with each UE in a set of UEs from the source NTN entity. Each UE in the set of UEs has a connection with the source NTN entity during the first time period. The target NTN entity may receive the UE context via an Xn interface. For example, the target NTN entity may receive the UE context using an XnAP control protocol.

[0143] exist Figure 7 In the context of , operation 1204 may be illustrated by the target gNB 702b receiving a UE context transfer 728 from the source gNB 702a. During the UE context transfer 728, the target gNB 702b may receive, from the source gNB 702a, a respective UE context for each of the UEs connected to the source gNB 702a at time period T1 or before time period T1.

[0144] At operation 1206, the target NTN entity may be configured to establish a corresponding connection with each UE in the set of UEs connected to the source NTN entity in the first time period based on a second time period indicated to each UE in the set of UEs connected to the source NTN entity in a message from the source NTN entity. In some aspects, the message includes one of a SIB or an RRC connection release message. In some aspects, the SIB includes one of SIB3 or SIB19. In some aspects, the RRC connection release message includes redirection information identifying the target NTN entity.

[0145] In some aspects, establishing a corresponding connection with each UE in the group of UEs handed over from the source NTN entity based on the second time period indicated to each UE in the message from the source NTN entity includes: receiving a corresponding request for RRC connection reestablishment from each UE in the group of UEs based on the second time period; and reestablishing the corresponding connection with each UE in the group of UEs based on the corresponding request.

[0146] In some other aspects, the UE may establish a connection associated with the target NTN entity by synchronizing with the target NTN entity (such as by acquiring a MIB and / or one or more SIBs sent by the target NTN entity, by performing a RACH procedure with the target NTN entity, etc.).

[0147] In some further aspects, establishing a corresponding connection with each UE in the group of UEs handed over from the source NTN entity based on the second time period indicated to each UE in the message from the source NTN entity includes: receiving a corresponding RRC connection request from each UE in the group of UEs; sending a corresponding RRC connection establishment message to each UE in the group of UEs in response to the corresponding RRC connection request; and receiving a corresponding RRC connection establishment completion message from each UE in the group of UEs based on the corresponding RRC connection establishment message.

[0148] In some further aspects, establishing a corresponding connection with each UE in the group of UEs handed over from the source NTN entity based on the second time period indicated to each UE in the message from the source NTN entity includes: sending a corresponding RRC connection reconfiguration message to each UE in the group of UEs. The RRC connection reconfiguration message may be used to configure one or more logical, transport and / or physical channels between the UE and the target NTN entity. Additionally or alternatively, the RRC connection reconfiguration message may be used to establish or modify one or more radio bearers of the UE through the target NTN entity.

[0149] exist Figure 7In the context of , operation 1206 may be illustrated by the target gNB 702b receiving an RRC connection reestablishment request 734 from the UE 704 during a time period T1+x that the target gNB 702b is available for after the feeder link switch 730. The target gNB 702b may send an RRC connection reestablishment complete message to the UE 704 based on the request 734.

[0150] exist Figure 8 In the context of , operation 1206 may be illustrated by the target gNB 802b synchronizing 832 with the UE 804 for a time period T1+x that is available to the target gNB 802b after the feeder link switch 830. In some aspects, the target gNB 802b may perform a RACH procedure with the UE 804 to synchronize 832 the UE 804 with the target gNB 802b.

[0151] At operation 1208, in some optional aspects, the target NTN entity may be configured to perform a handover of each UE in the set of UEs from the source NTN entity based on the switching of the feeder link. In some aspects, the handover may be based on a configuration associated with a conditional handover from the source NTN entity, and at least one UE in the set of UEs may be handed over from the source NTN entity based on the configuration. For example, the target NTN entity may receive a handover request from the source NTN entity, and based thereon, the target NTN entity may send a handover request confirmation to the source NTN entity. The target NTN entity may also receive an SN status transfer message from the source NTN entity, for example, after sending the handover request confirmation.

[0152] exist Figure 7 In the context of , operation 1208 may be illustrated by the target gNB 702b performing a handover of the UE 704 from the source gNB 702a based on the feeder link switch 730 in the time period T1 (e.g., in the target gNB availability time period T1+x). Figure 8 In the context of , operation 1208 may be illustrated by the target gNB 802b performing a handover of the UE 804 from the source gNB 802a based on a feeder link switch 830 in time period T1 (e.g., in a target gNB availability time period T1+x).

[0153] Fig.13 1300 is a diagram illustrating an example of a hardware implementation of an apparatus 1302. The apparatus 1302 may be a UE or similar device, or the apparatus 1302 may be a component of a UE or similar device. The apparatus 1302 may include a cellular baseband processor 1304 (also referred to as a modem) and / or a cellular RF transceiver 1322, which may be coupled together and / or integrated into the same package, component, circuit, chip, and / or other circuitry.

[0154] In some aspects, the device 1302 may accommodate or include one or more subscriber identity module (SIM) cards 1320, which may include one or more integrated circuits, chips, or similar circuits, and may be removable or embedded. One or more SIM cards 1320 may carry identification and / or authentication information, such as an International Mobile Subscriber Identity (IMSI) and / or IMSI-related keys. In addition, the device 1302 may include one or more of an application processor 1306 coupled to a secure digital (SD) card 1308 and a screen 1310, a Bluetooth module 1312, a wireless local area network (WLAN) module 1314, a global positioning system (GPS) module 1316, and / or a power source 1318.

[0155] The cellular baseband processor 1304 communicates with the UE 104 and / or the base station 102 / 180 via the cellular RF transceiver 1322. The cellular baseband processor 1304 may include a computer-readable medium / memory. The computer-readable medium / memory may be non-transitory. The cellular baseband processor 1304 is responsible for general processing, including executing software stored on the computer-readable medium / memory. The software, when executed by the cellular baseband processor 1304, enables the cellular baseband processor 1304 to perform the various functions described above. The computer-readable medium / memory may also be used to store data manipulated by the cellular baseband processor 1304 when executing the software. The cellular baseband processor 1304 also includes a receiving component 1330, a communication manager 1332, and a sending component 1334. The communication manager 1332 includes one or more of the illustrated components. The components within the communication manager 1332 may be stored in a computer-readable medium / memory and / or configured as hardware within the cellular baseband processor 1304.

[0156] exist Figure 4 In the context of , the cellular baseband processor 1304 may be a component of the UE 450 and may include the memory 460 and / or at least one of the TX processor 468, the RX processor 456, and / or the controller / processor 459. In one configuration, the device 1302 may be a modem chip and / or may be implemented as the baseband processor 1304, while in another configuration, the device 1302 may be the entire UE (e.g., Figure 4 UE 450) and may include some or all of the above components, circuits, chips, and / or other circuits exemplified in the context of device 1302. In one configuration, the cellular RF transceiver 1322 may be implemented as at least one of the transmitter 454TX and / or the receiver 454RX.

[0157] The receiving component 1330 may be configured to receive signaling on a wireless channel, such as signaling from a base station 102 / 180 or a UE 104. The sending component 1334 may be configured to send signaling on a wireless channel, such as signaling to a base station 102 / 180 or a UE 104. The communication manager 1332 may coordinate or manage some or all wireless communications by the device 1302, including wireless communications across the receiving component 1330 and the sending component 1334.

[0158] Receiving component 1330 may provide some or all data and / or control information included in received signaling to communications manager 1332, and communications manager 1332 may generate and provide some or all data and / or control information to be included in transmitted signaling to transmitting component 1334. Communications manager 1332 may include various illustrated components, including one or more components configured to process received data and / or control information and / or one or more components configured to generate data and / or control information for transmission.

[0159] The communication manager 1332 may include an identification component 1340, a reporting component 1342, and a connection component 1344. The receiving component 1330 may be configured to receive a message in the NTN indicating a feeder link switch from a source NTN entity 102 / 180 102 / 180 to a target NTN entity 102' / 180' and a time period associated with the switch, e.g., as in conjunction with Fig.10 In some aspects, the message includes one of a SIB or an RRC connection release message. In some aspects, the SIB includes one of SIB3 or SIB19. In some aspects, the RRC connection release message includes redirection information, and the connection may be further established based on the redirection information.

[0160] The identification component 1340 may be configured to identify the target NTN entity 102' / 180' based on information associated with the target NTN entity 102' / 180' included in the message, for example, in combination with Fig.10 1004. For example, the identification component 1340 may decode the received message to obtain information indicating one or more of the following: a carrier frequency of the target NTN entity 102' / 180', an ARFCN of the target NTN entity 102' / 180', a subcarrier spacing of an SSB sent by the target NTN entity 102' / 180', and / or an SSB measurement and timing configuration associated with the target NTN entity 102' / 180'. The identification component 1340 may tune a receiver circuit (e.g., a circuit of an RF front end and / or a circuit of a PHY layer) to the carrier frequency and / or ARFCN of the target NTN entity 102' / 180'.

[0161] The reporting component 1342 can be configured to avoid reporting the RLF associated with the source NTN entity 102 / 180 based on the message, for example, as combined with Fig.10 1006. The message may indicate to the reporting component 1342 that a feeder link switch is about to occur. If the feeder link switch is a hard switch in time period T1, the device 1302 may lose connectivity to the NTN (temporarily) in time period T1. In one example, the reporting component 1342 may avoid reporting the RLF based on an indication that the switch is associated with the RLF. In some aspects, to avoid reporting the RLF, the reporting component 1342 may be configured to detect the RLF associated with the source NTN entity 102 / 180, but may be configured to avoid reporting the RLF (e.g., based on the received message). In some other aspects, to avoid reporting the RLF, the reporting component 1342 may be configured to avoid detecting the RLF during a time period that occurs concurrently with the time period T1 of the feeder link switch (e.g., based on the received message).

[0162] The connection component 1344 may be configured to establish a connection associated with the target NTN entity 102' / 180' based on the time period, for example, in conjunction with Fig.10 1008. The connection component 1344 may establish a connection with the target NTN entity 102' / 180' based on a time period T1+x during which the target NTN entity 102' / 180' is available after the feeder link switch, which may be indicated in the received message indicating the switch.

[0163] In some aspects, the connection component 1344 can establish a connection associated with the target NTN entity 102' / 180' by reestablishing an RRC connection with the NTN. For example, the sending component 1334 can be configured to send an RRC connection reestablishment request to the target NTN entity 102' / 180' based on a time period (e.g., time period T1+x), and the connecting component 1344 can be configured to reestablish the connection associated with the target NTN entity 102' / 180' based on the RRC connection reestablishment request. The receiving component 1330 can receive an RRC connection reestablishment complete message from the target NTN entity 102' / 180', which can indicate that the bearer has been allocated to the device 1302 and the device 1302 is (re)connected with the NTN through the target NTN entity 102' / 180'.

[0164] In some other aspects, the connection component 1344 can establish a connection associated with the target NTN entity 102' / 180' by attaching to the target NTN entity 102' / 180'. For example, the connection component 1344 can synchronize with the target NTN entity 102' / 180', such as by acquiring a MIB and / or one or more SIBs sent by the target NTN entity 102' / 180', by performing a RACH procedure with the target NTN entity 102' / 180', and the like.

[0165] In yet other aspects, the connecting component 1344 can establish a connection associated with the target NTN entity 102' / 180' by sending an RRC connection request to the target NTN entity 102' / 180'. The receiving component 1330 can receive an RRC connection establishment message from the target NTN entity 102' / 180' in response to the RRC connection request. Based on the RRC connection establishment message, the sending component 1334 can send an RRC connection establishment complete message to the target NTN entity 102' / 180'.

[0166] In yet other aspects, the connection component 1344 may establish a connection associated with the target NTN entity 102' / 180' by receiving an RRC connection reconfiguration message from the target NTN entity 102' / 180'. The RRC connection reconfiguration message may be used to configure one or more logical, transport, and / or physical channels between the device 1302 and the target NTN entity 102' / 180'. Additionally or alternatively, the RRC connection reconfiguration message may be used to establish or modify one or more radio bearers of the device 1302 through the target NTN entity 102' / 180'.

[0167] In some aspects, the connection can be established further based on information associated with the target NTN entity 102' / 180'. For example, the information associated with the target NTN entity 102' / 180' can include redirection information included in the RRC connection release message with redirection information. The connection component 1344 can decode and parse the redirection information to obtain the carrier frequency, ARFCN, SSB subcarrier spacing, SSB measurement and timing configuration, and / or other information that can be used alone or with other information to identify the target NTN entity 102' / 180' and / or operate on a cell provided by the target NTN entity 102' / 180'.

[0168] In some aspects, when a configuration associated with a conditional handover of the device 1302 from the source NTN entity 102 / 180 to the target NTN entity 102' / 180' has been received from the source NTN entity 102 / 180, the connection component 1344 may further establish a connection associated with the target NTN entity 102' / 180' based on the conditional handover. The conditional handover configuration may indicate a set of conditions to be satisfied in order for the connection component 1344 to initiate a handover procedure from the source NTN entity 102 / 180 to the target NTN entity 102' / 180'. For example, the configuration may indicate a time period T1 during which a feeder link switch 730 is to occur, which may result in the source NTN entity 102 / 180 becoming unavailable to the connection component 1344 for connectivity. Thus, when the connection component 1344 detects a condition that the clock time (or current time) is equal to the time period T1 (or within a threshold margin of the time period T1), the connection component 1344 may initiate a conditional handover procedure from the source NTN entity 102 / 180 to the target NTN entity 102' / 180'.

[0169] The device 1302 may include executing Figure 7 , Figure 8 and / or Fig.10 Some or all of the additional components of the aforementioned call flow diagrams and / or the blocks, operations, signaling, etc. of the algorithms in the flow diagrams. Therefore, Figure 7 , Figure 8 and / or Fig.10 Some or all of the blocks, operations, signaling, etc. in the aforementioned call flow diagrams and / or flow diagrams may be performed by one or more components, and the device 1302 may include one or more of such components. These components may be one or more hardware components that are specifically configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored in a computer-readable medium so as to be implemented by a processor, or some combination thereof.

[0170] In one configuration, the apparatus 1302 (and specifically, the cellular baseband processor 1304) includes means for receiving, in the NTN, a message indicating a feeder link switch from a source NTN entity to a target NTN entity and a time period associated with the switch; and means for establishing a connection associated with the target NTN entity based on the time period.

[0171] In one configuration, the message includes one of a SIB or an RRC connection release message.

[0172] In one configuration, the SIB comprises one of SIB3 or SIB19.

[0173] In one configuration, the RRC connection release message includes redirection information, and the connection is established further based on the redirection information.

[0174] In one configuration, the apparatus 1302 (and specifically the cellular baseband processor 1304) may also include means for identifying the target NTN entity based on information associated with the target NTN entity included in the message, and further establishing the connection based on the information associated with the target NTN entity.

[0175] In one configuration, the time period includes at least one of a first time period during which the handover occurs or a second time period available for the target NTN entity to establish the connection, the second time period being offset from the first time period.

[0176] In one configuration, the means for establishing the connection associated with the target NTN entity based on the time period is configured to send a request for RRC connection reestablishment to the target NTN entity based on the time period; and reestablish the connection associated with the target NTN entity based on the request.

[0177] In one configuration, the apparatus 1302 (and specifically the cellular baseband processor 1304) may also include means for refraining from reporting a RLF associated with the source NTN entity based on the message.

[0178] In one configuration, the message also includes an indication that the handover is associated with the RLF, and the avoiding reporting the RLF is based on the indication that the handover is associated with the RLF.

[0179] In one configuration, the means for avoiding reporting the RLF is configured to detect the RLF associated with the source NTN entity; and avoid sending a report indicating the RLF based on the message.

[0180] In one configuration, the means for avoiding reporting the RLF is configured to avoid detecting the RLF associated with the source NTN entity based on the message.

[0181] In one configuration, when a configuration associated with a conditional handover of the UE from the source NTN entity to the target NTN entity has been received from the source NTN entity, the connection is further established based on the conditional handover.

[0182] The aforementioned means may be one or more of the aforementioned components of the apparatus 1302 configured to perform the functions recited by the aforementioned means. As described above, the apparatus 1302 may include the TX processor 468, the RX processor 456, and the controller / processor 459. Therefore, in one configuration, the aforementioned means may be the TX processor 468, the RX processor 456, and the controller / processor 459 configured to perform the functions recited by the aforementioned means.

[0183] Fig.14 1400 is an example of a hardware implementation of an exemplary apparatus 1402. The apparatus 1402 may be a base station or similar device or system, or the apparatus 1402 may be a component of a base station or similar device or system. The apparatus 1402 may include a baseband unit 1404. The baseband unit 1404 may communicate via a cellular RF transceiver. For example, the baseband unit 1404 may communicate with the UE 104 (such as for downlink communication and / or uplink communication) and / or communicate with the base station 102 / 180 (such as for IAB) via the cellular RF transceiver.

[0184] The baseband unit 1404 may include a computer-readable medium / memory that may be non-transitory. The baseband unit 1404 is responsible for general processing, including executing software stored on the computer-readable medium / memory. The software, when executed by the baseband unit 1404, enables the baseband unit 1404 to perform the various functions described above. The computer-readable medium / memory may also be used to store data manipulated by the baseband unit 1404 when executing the software. The baseband unit 1404 also includes a receiving component 1430, a communication manager 1432, and a sending component 1434. The communication manager 1432 includes one or more of the illustrated components. The components within the communication manager 1432 may be stored in a computer-readable medium / memory and / or configured as hardware within the baseband unit 1404. The baseband unit 1404 may be a component of the base station 410 and may include a memory 476 and / or at least one of the TX processor 416, the RX processor 470, and the controller / processor 475.

[0185] The receiving component 1430 may be configured to receive signaling on a wireless channel, such as signaling from the UE 104 or the base station 102 / 180. The sending component 1434 may be configured to send signaling on a wireless channel, such as signaling to the UE 104 or the base station 102 / 180. The communication manager 1432 may coordinate or manage some or all wireless communications performed by the device 1402, including wireless communications across the receiving component 1430 and the sending component 1434.

[0186] The receiving component 1430 may provide some or all of the data and / or control information included in the received signaling to the communication manager 1432, and the communication manager 1432 may generate and provide some or all of the data and / or control information to be included in the transmitted signaling to the transmitting component 1434. The communication manager 1432 may include various illustrated components, including one or more components configured to process the received data and / or control information and / or one or more components configured to generate data and / or control information for transmission. In some aspects, the generation of the data and / or control information may include packetizing or otherwise reformatting the data and / or control information received from the core network (such as the core network 190 or the EPC 160) for transmission.

[0187] The communication manager 1432 may include a timing component 1440 and a handover component 1442. The timing component 1440 may be configured to determine a first time period associated with a handover of a feeder link from the device 1402 to the target NTN entity 102' / 180', for example, as described in conjunction with Fig.11 1102. In some aspects, the timing component 1440 entity may be notified of the time period T1 during which the feeder link switching will occur. For example, the timing component 1440 may be notified by a gateway or other similar network entity configured to communicate with the device 1402. In some other aspects, the timing component 1440 may also be notified of the target NTN entity 102' / 180' that a group of UEs 104s connected to the device 1402 during the time period T1 will be connected to the target NTN entity during another time period T1+x after the feeder link switching. For example, the timing component 1440 may be informed of a cell ID (e.g., PCI) of the target NTN entity 102' / 180', a carrier frequency of the target NTN entity 102' / 180', an ARFCN of the target NTN entity 102' / 180', a subcarrier spacing of SSBs transmitted by the target NTN entity 102' / 180', an smtc configuration associated with the target NTN entity 102' / 180', and / or other redirection information that may be used by the UE 104 to identify the target NTN entity 102' / 180' and / or operate on a cell provided by the target NTN entity 102' / 180'.

[0188] The sending component 1434 may be configured to send a message indicating the switching of the feeder link based on the first time period, the message also indicating a second time period associated with the availability of the target NTN entity 102' / 180', for example, as combined with Fig.111104. In some aspects, the message includes one of a SIB or an RRC connection release message. For example, the SIB may include one of SIB3 or SIB19. In some aspects, the RRC connection release message may include redirection information identifying the target NTN entity 102' / 180'. In some aspects, the message also includes an indication that the switch is associated with RLF. Such an indication that the switch is associated with RLF may prevent UE 104s from reporting RLF that may occur concurrently with the feeder link switch.

[0189] The sending component 1434 may be configured to send, to the target NTN entity 102' / 180', a respective context associated with each UE in a set of UEs 104 that have a connection with the device 1402 during the first time period, e.g., as described in conjunction with Fig.11 1106. The sending component 1434 can send the UE 104 context via the Xn interface. For example, the sending component 1434 can use the XnAP control protocol to send the UE 104 context.

[0190] The handover component 1442 may be configured to perform a handover of each UE in a group of UEs 104 to a target NTN entity 102' / 180' based on the switching of the feeder link associated with the first time period, for example, as described in conjunction with Fig.11 1108 of . For example, the sending component 1434 may send a handover request to the target NTN entity 102' / 180', and based on this, the receiving component 1430 may receive a handover request confirmation from the target NTN entity 102' / 180'. The sending component 1434 may also send a sequence number (SN) status transfer message to the target NTN entity 102' / 180', for example, after receiving the handover request confirmation. In some aspects, the sending component 1434 may be configured to send a configuration associated with a conditional handover to the target NTN entity 102' / 180' to at least one UE in the group of UEs 104, and may hand over the at least one UE in the group of UEs 104 to the target NTN entity 102' / 180' based on the configuration.

[0191] In some aspects, the sending component 1434 may send an RRC connection release message (e.g., before or during a handover procedure or without performing a handover procedure). The RRC connection release message may be an RRC connection release with a redirection message that includes redirection information associated with the target gNB. For example, the handover component 1442 may be notified of a (hard or soft) switch of a feeder link at time period T1 and information associated with the target NTN entity 102' / 180' that will be available after the feeder link switch. The handover component 1442 may include information indicating the target gNB, the time period T1, and / or the time period T1+x during which the target gNB will become available.

[0192] The redirection information may indicate one or more of the following: a cell ID (e.g., PCI) of the target NTN entity 102' / 180', a carrier frequency of the target NTN entity 102' / 180', an ARFCN of the target NTN entity 102' / 180', a subcarrier spacing of SSBs sent by the target NTN entity 102' / 180', and / or SSB measurement and timing configuration associated with the target NTN entity 102' / 180', some or all of which may be used by the UE 104 to identify the target NTN entity 102' / 180' and / or operate on a cell provided by the target NTN entity 102' / 180'. The redirection information may also indicate an availability time at which the target NTN entity 102' / 180' is available after the feeder link switch. The availability time may be indicated as a reference time (e.g., feeder link switch time period T1) to which an offset x may be added.

[0193] The device 1402 may include executing Figure 7 , Figure 8 and / or Fig.11 Some or all of the additional components of the aforementioned call flow diagrams and / or the blocks, operations, signaling, etc. of the algorithms in the flow diagrams. Therefore, Figure 7 , Figure 8 and / or Fig.11 Some or all of the blocks, operations, signaling, etc. in the aforementioned call flow diagrams and / or flow diagrams may be performed by components, and the device 1402 may include one or more of those components. These components may be one or more hardware components that are specifically configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored in a computer-readable medium so as to be implemented by a processor, or some combination thereof.

[0194] In one configuration, the apparatus 1402 (and specifically, the baseband unit 1404) includes means for determining a first time period associated with a switch of a feeder link from the source NTN entity to a target NTN entity; and means for sending a message indicating the switch of the feeder link based on the first time period, the message also indicating a second time period associated with the availability of the target NTN entity.

[0195] In one configuration, the message includes one of a SIB or an RRC connection release message.

[0196] In one configuration, the SIB comprises one of SIB3 or SIB19.

[0197] In one configuration, the RRC connection release message includes redirection information identifying a target NTN entity.

[0198] In one configuration, the apparatus 1402 (and specifically the baseband unit 1404) may also include means for sending, in a single message, to the target NTN entity a respective context associated with each UE in a group of UEs having a connection with the source NTN entity during the first time period.

[0199] In one configuration, the apparatus 1402 (and specifically the baseband unit 1404) may further include means for performing a handover of each UE in a group of UEs to the target NTN entity based on the switching of the feeder link associated with the first time period prior to the second time period.

[0200] In one configuration, the apparatus 1402 (and specifically the baseband unit 1404) may also include a component for sending a configuration associated with the conditional handover to the target NTN entity to at least one UE in the group of UEs, and handing over the at least one UE in the group of UEs to the target NTN entity based on the configuration.

[0201] In one configuration, the second time period is offset from the first time period.

[0202] In one configuration, the message also includes an indication that the handover is associated with RLF.

[0203] The aforementioned means may be one or more of the aforementioned components of the apparatus 1402 configured to perform the functions recited by the aforementioned means. As described above, the apparatus 1402 may include the TX processor 416, the RX processor 470, and the controller / processor 475. Therefore, in one configuration, the aforementioned means may be the TX processor 416, the RX processor 470, and the controller / processor 475 configured to perform the functions recited by the aforementioned means.

[0204] Fig.15 1500 is an example of a hardware implementation of an exemplary apparatus 1502. The apparatus 1502 may be a base station or similar device or system, or the apparatus 1502 may be a component of a base station or similar device or system. The apparatus 1502 may include a baseband unit 1504. The baseband unit 1504 may communicate via a cellular RF transceiver. For example, the baseband unit 1504 may communicate with the UE 104 (such as for downlink communication and / or uplink communication) and / or communicate with the base station 102 / 180 (such as for IAB) via the cellular RF transceiver.

[0205] The baseband unit 1504 may include a computer-readable medium / memory that may be non-transitory. The baseband unit 1504 is responsible for general processing, including executing software stored on the computer-readable medium / memory. The software, when executed by the baseband unit 1504, enables the baseband unit 1504 to perform the various functions described above. The computer-readable medium / memory may also be used to store data manipulated by the baseband unit 1504 when executing the software. The baseband unit 1504 also includes a receiving component 1530, a communication manager 1532, and a sending component 1534. The communication manager 1532 includes one or more of the illustrated components. The components within the communication manager 1532 may be stored in a computer-readable medium / memory and / or configured as hardware within the baseband unit 1504. The baseband unit 1504 may be a component of the base station 410 and may include a memory 476 and / or at least one of the TX processor 416, the RX processor 470, and the controller / processor 475.

[0206] The receiving component 1530 may be configured to receive signaling on a wireless channel, such as signaling from the UE 104 or the base station 102 / 180. The sending component 1534 may be configured to send signaling on a wireless channel, such as signaling to the UE 104 or the base station 102 / 180. The communication manager 1532 may coordinate or manage some or all wireless communications performed by the device 1502, including wireless communications across the receiving component 1530 and the sending component 1534.

[0207] Receiving component 1530 may provide some or all of the data and / or control information included in the received signaling to communication manager 1532, and communication manager 1532 may generate and provide some or all of the data and / or control information to be included in the transmitted signaling to transmitting component 1534. Communication manager 1532 may include various illustrated components, including one or more components configured to process received data and / or control information and / or one or more components configured to generate data and / or control information for transmission. In some aspects, the generation of data and / or control information may include packetizing or otherwise reformatting data and / or control information received from a core network, such as core network 190 or EPC 160, for transmission.

[0208] The communication manager 1532 may include a feeder link component 1540, a handover component 1542, and a connection component 1544. The feeder link component 1540 may be configured to obtain a feeder link in a first time period based on a handover of a feeder link from a source NTN entity 102 / 180, for example, as described in conjunction with Fig.12 1202. For example, the feed link component 1540 can receive information indicating a set of satellites that can supply feeder links to the device 1502. For example, once one of the satellites in the set of satellites reaches a switching threshold in a time period T1, the feed link component 1540 can connect to the one of the satellites in the set of satellites.

[0209] The receiving component 1530 can receive, from the source NTN entity 102 / 180, a respective UE 104 context associated with each UE in a set of UEs 104, e.g., as described in conjunction with Fig.12 1204. Each UE in the group of UEs 104 may have a connection with the source NTN entity 102 / 180 in the first time period. The receiving component 1530 may receive the UE 104 context via the Xn interface. For example, the receiving component 1530 may receive the UE 104 context using the XnAP control protocol.

[0210] The connection component 1544 may be configured to establish a corresponding connection with each UE in the set of UEs 104 during a first time period based on a second time period indicated in a message from the source NTN entity 102 / 180 to each UE in the set of UEs 104 connected to the source NTN entity 102 / 180, e.g., as described in conjunction with Fig.12 In some aspects, the message includes one of a SIB or an RRC connection release message. In some aspects, the SIB includes one of SIB3 or SIB19. In some aspects, the RRC connection release message includes redirection information of the identification device 1502.

[0211] In some aspects, establishing a corresponding connection with each UE in a group of UEs 104 handed over from the source NTN entity 102 / 180 based on a second time period indicated to each UE in the group of UEs 104 in a message from the source NTN entity 102 / 180 includes: receiving a corresponding request for RRC connection re-establishment from each UE in the group of UEs 104 based on the second time period; and re-establishing the corresponding connection with each UE in the group of UEs 104 based on the corresponding request.

[0212] In some other aspects, UE 104 can establish a connection associated with device 1502 by synchronizing with connection component 1544 (such as by obtaining the MIB and / or one or more SIBs sent by transmission component 1534, by performing a RACH procedure with device 1502, etc.).

[0213] In some further aspects, establishing a corresponding connection with each UE in a group of UEs 104 handed over from the source NTN entity 102 / 180 based on the second time period indicated to each UE in the message from the source NTN entity 102 / 180 includes: receiving a corresponding RRC connection request from each UE in the group of UEs 104; sending a corresponding RRC connection establishment message to each UE in the group of UEs 104 in response to the corresponding RRC connection request; and receiving a corresponding RRC connection establishment completion message from each UE in the group of UEs 104 based on the corresponding RRC connection establishment message.

[0214] In yet other aspects, establishing a respective connection with each UE in a group of UEs 104 handed over from the source NTN entity 102 / 180 based on the second time period indicated to each UE in the group of UEs 104 in the message from the source NTN entity 102 / 180 includes sending a respective RRC connection reconfiguration message to each UE in the group of UEs 104. The RRC connection reconfiguration message may be used to configure one or more logical, transport, and / or physical channels between the UE 104 and the device 1502. Additionally or alternatively, the RRC connection reconfiguration message may be used to establish or modify one or more radio bearers of the UE 104 by the device 1502.

[0215] The handover component 1542 may be configured to perform a handover of each UE in a group of UEs 104 from a source NTN entity 102 / 180 based on the switching of the feeder link, for example, as described in conjunction with Fig.121208 of . In some aspects, the handover may be based on a configuration associated with a conditional handover from the source NTN entity 102 / 180, and at least one UE in a group of UEs 104 may be handed over from the source NTN entity 102 / 180 based on the configuration. For example, the handover component 1542 may receive a handover request from the source NTN entity 102 / 180, and based on this, the handover component 1542 may send a handover request confirmation to the source NTN entity 102 / 180. The handover component 1542 may also receive an SN status transfer message from the source NTN entity 102 / 180, for example, after sending the handover request confirmation.

[0216] Means 1502 may include executing Figure 7 , Figure 8 and / or Fig.12 Some or all of the additional components of the aforementioned call flow diagrams and / or the blocks, operations, signaling, etc. of the algorithms in the flow diagrams. Therefore, Figure 7 , Figure 8 and / or Fig.12 Some or all of the blocks, operations, signaling, etc. in the aforementioned call flow diagrams and / or flow diagrams may be performed by components, and the apparatus 1502 may include one or more of those components. These components may be one or more hardware components that are specifically configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored in a computer-readable medium so as to be implemented by a processor, or some combination thereof.

[0217] In one configuration, the apparatus 1502 (and specifically, the baseband unit 1504) includes a component for obtaining a feeder link in a first time period based on a switching of the feeder link from a source NTN entity; and a component for establishing a corresponding connection with each UE in a group of UEs connected to the source NTN entity in the first time period based on a second time period indicated to each UE in the group of UEs connected to the source NTN entity in a message from the source NTN entity.

[0218] In one configuration, the apparatus 1502 (and specifically the baseband unit 1504) may also include means for receiving, from the source NTN entity, a respective context associated with each UE in the set of UEs, each UE in the set of UEs having a connection with the source NTN entity during the first time period.

[0219] In one configuration, the contexts respectively associated with the group of UEs are received in a single message from the source NTN entity.

[0220] In one configuration, the apparatus 1502 (and specifically the baseband unit 1504) may also include means for communicating information associated with the feeder link switch from the source NTN entity to the target NTN entity over an Xn interface.

[0221] In one configuration, the information associated with the feeder link switch includes at least one of: the first time period during which the feeder link switch occurs; the second time period during which the target NTN entity is available; or an indication of whether the feeder link switch is associated with a radio link failure.

[0222] In one configuration, the apparatus 1502 (and specifically the baseband unit 1504) may also include means for performing a handover of each UE in the group of UEs from the source NTN entity based on the switching of the feeder link before the second time period.

[0223] In one configuration, the handover is based on a configuration associated with a conditional handover from the source NTN entity, and at least one UE in the group of UEs is handed over from the source NTN entity based on the configuration.

[0224] In one configuration, the second time period is offset from the first time period.

[0225] In one configuration, the component for establishing a corresponding connection with each UE in the group of UEs handed over from the source NTN entity based on the second time period indicated to each UE in the message from the source NTN entity is configured to receive a corresponding request for RRC connection reestablishment from each UE in the group of UEs based on the second time period; and reestablish the corresponding connection with each UE in the group of UEs based on the corresponding request.

[0226] The aforementioned means may be one or more of the aforementioned components of the apparatus 1502 configured to perform the functions recited by the aforementioned means. As described above, the apparatus 1502 may include the TX processor 416, the RX processor 470, and the controller / processor 475. Therefore, in one configuration, the aforementioned means may be the TX processor 416, the RX processor 470, and the controller / processor 475 configured to perform the functions recited by the aforementioned means.

[0227] The specific order or hierarchy of each frame or operation in each of the above-mentioned processes, flow charts and other diagrams disclosed herein is an illustration of an exemplary method. Based on design preferences, the specific order or hierarchy of frames or operations in each of these processes, flow charts and other diagrams can be rearranged, omitted and / or performed concurrently without departing from the scope of the present disclosure. In addition, some frames or operations can be combined or omitted. The attached method claims present the elements of various frames or operations in an exemplary order, and are not meant to be limited to the specific order or hierarchy presented.

[0228] The following examples are merely illustrative and may be combined with aspects of other embodiments or teachings described herein, but are not limited thereto.

[0229] Embodiment 1 is a device at a UE, the device being configured to: receive a message in an NTN indicating a feeder link switch from a source NTN entity to a target NTN entity and a time period associated with the switch; and establish a connection associated with the target NTN entity based on the time period.

[0230] Embodiment 2 may be the apparatus according to embodiment 1, and the message includes one of a SIB or an RRC connection release message.

[0231] Embodiment 3 may be the apparatus according to embodiment 2, and the SIB includes one of SIB3 or SIB19.

[0232] Embodiment 4 may be the apparatus according to embodiment 2, and the RRC connection release message includes redirection information, and the connection is further established based on the redirection information.

[0233] Embodiment 5 may be the apparatus according to embodiment 1, and the apparatus is further configured to: identify the target NTN entity based on information associated with the target NTN entity included in the message, and further establish the connection based on the information associated with the target NTN entity.

[0234] Embodiment 6 may be the apparatus according to embodiment 1, and the time period includes at least one of a first time period during which the handover occurs or a second time period during which the target NTN entity can use to establish the connection, the second time period being offset from the first time period.

[0235] Embodiment 7 may be the apparatus according to embodiment 1, and establishing the connection associated with the target NTN entity based on the time period includes: sending a request for RRC connection reestablishment to the target NTN entity based on the time period; and reestablishing the connection associated with the target NTN entity based on the request.

[0236] Embodiment 8 may be the apparatus according to embodiment 1, and the apparatus is further configured to: avoid reporting a RLF associated with the source NTN entity based on the message.

[0237] Embodiment 9 may be the apparatus according to embodiment 8, and the message further includes an indication that the handover is associated with the RLF, and the avoiding reporting the RLF is based on the indication that the handover is associated with the RLF.

[0238] Embodiment 10 may be the apparatus according to embodiment 8, and avoiding reporting the RLF comprises: detecting the RLF associated with the source NTN entity; and avoiding sending a report indicating the RLF based on the message.

[0239] Embodiment 11 may be the apparatus according to embodiment 8, and avoiding reporting the RLF includes avoiding detecting the RLF associated with the source NTN entity based on the message.

[0240] Embodiment 12 may be the apparatus according to embodiment 1, and when a configuration associated with a conditional handover of the UE from the source NTN entity to the target NTN entity has been received from the source NTN entity, the connection is further established based on the conditional handover.

[0241] Embodiment 13 may be a device at a source NTN entity, the device being configured to determine a first time period associated with a switch of a feeder link from the source NTN entity to a target NTN entity; and to send a message indicating the switch of the feeder link based on the first time period, the message also indicating a second time period associated with the availability of the target NTN entity.

[0242] Embodiment 14 may be the apparatus according to embodiment 13, and the message includes one of a SIB or an RRC connection release message.

[0243] Embodiment 14 may be the apparatus according to embodiment 14, and the SIB includes one of SIB3 or SIB19.

[0244] Embodiment 16 may be the apparatus according to embodiment 14, and the RRC connection release message includes redirection information identifying the target NTN entity.

[0245] Embodiment 17 may be the apparatus according to embodiment 13, and the apparatus is further configured to: send, to the target NTN entity in a single message, a respective context associated with each UE in a group of UEs having a connection with the source NTN entity during the first time period.

[0246] Embodiment 18 may be the apparatus according to embodiment 13, and the apparatus is further configured to: before the second time period, perform handover of each UE in a group of UEs to the target NTN entity based on the switching of the feeder link associated with the first time period.

[0247] Embodiment 19 may be an apparatus according to embodiment 18, and the apparatus is further configured to: send a configuration associated with a conditional handover to the target NTN entity to at least one UE in the group of UEs, and hand over the at least one UE in the group of UEs to the target NTN entity based on the configuration.

[0248] Embodiment 20 may be the apparatus according to embodiment 13, and the second time period is offset from the first time period.

[0249] Embodiment 21 may be the apparatus according to embodiment 13, and the message further includes an indication that the handover is associated with RLF.

[0250] Embodiment 22 may be a device at a target NTN entity, the device being configured to: obtain the feeder link in a first time period based on switching of the feeder link from a source NTN entity; and establish a corresponding connection with each UE in a group of UEs connected to the source NTN entity in the first time period based on a second time period indicated to each UE in the group of UEs connected to the source NTN entity in a message from the source NTN entity.

[0251] Embodiment 23 may be an apparatus according to embodiment 22, and the apparatus is further configured to: receive, from the source NTN entity, a corresponding context associated with each UE in the group of UEs, each UE in the group of UEs having a connection with the source NTN entity in the first time period.

[0252] Embodiment 24 may be the apparatus according to embodiment 23, and the contexts respectively associated with the group of UEs are received in a single message from the source NTN entity.

[0253] Embodiment 25 may be the apparatus according to embodiment 23, and the apparatus is further configured to: communicate information associated with feeder link switching from the source NTN entity to the target NTN entity through an Xn interface.

[0254] Embodiment 26 may be an apparatus according to embodiment 25, and the information associated with the feeder link switching includes at least one of the following: the first time period during which the feeder link switching occurs; the second time period during which the target NTN entity is available; or an indication of whether the feeder link switching is associated with a radio link failure.

[0255] Embodiment 27 may be the apparatus according to embodiment 22, and the apparatus is further configured to: perform a handover of each UE in the group of UEs from the source NTN entity based on the switching of the feeder link.

[0256] Embodiment 28 may be the apparatus of embodiment 27, and the handover is based on a configuration associated with a conditional handover from the source NTN entity, and at least one UE in the group of UEs is handed over from the source NTN entity based on the configuration.

[0257] Embodiment 29 may be the apparatus according to embodiment 22, and the second time period is offset from the first time period.

[0258] Embodiment 30 may be an apparatus according to embodiment 22, and establishing a corresponding connection with each UE in the group of UEs handed over from the source NTN entity based on the second time period indicated to each UE in the group of UEs in the message from the source NTN entity includes: receiving a corresponding request for RRC connection reestablishment from each UE in the group of UEs based on the second time period; and reestablishing the corresponding connection with each UE in the group of UEs based on the corresponding request.

[0259] The previous description is provided to enable one of ordinary skill in the art to practice the various aspects described herein. Various modifications to these aspects will be readily understood by one of ordinary skill in the art, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not intended to be limited to the various aspects shown herein, but should be given the full scope consistent with the language. Therefore, the language employed herein is not intended to limit the scope of the claims to only those aspects shown herein, but should be given the full scope consistent with the language of the claims.

[0260] As an example, the language "determine" may encompass a wide variety of actions and, therefore, may not be limited to the concepts and aspects explicitly described or illustrated by the present disclosure. In some contexts, "determine" may include calculating, computing, processing, measuring, deriving, investigating, searching (e.g., searching in a table, database, or another data structure), ascertaining, resolving, selecting, choosing, establishing, and the like. In some other contexts, "determining" may include communications and / or memory operations / procedures such as "receiving" (e.g., receiving information), "accessing" (e.g., accessing data in a memory), "detecting," and the like by obtaining information or values.

[0261] As another example, reference to a singular element is not intended to mean "there is and only one" (unless otherwise specifically stated), but "one or more". In addition, terms such as "if", "when ..." and "when ..." should be interpreted as meaning "under ..." conditions, rather than implying a direct temporal relationship or reaction. That is, these phrases (e.g., "when ...") do not imply an immediate action in response to the occurrence of an action or event or during the occurrence of an action or event, but imply that another action or event will occur if a condition is met, without requiring a specific or immediate time constraint or direct correlation for the occurrence of the other action or event. The word "exemplary" is used herein to mean "used as an example, instance, or illustration". Any aspect described herein as "exemplary" is not necessarily interpreted as being preferred or having an advantage over other aspects. Unless otherwise specified, the term "some" refers to one or more. Combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof” include any combination of A, B, and / or C, and may include multiple A, multiple B, or multiple C. Specifically, combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof” may be only A, only B, only C, A and B, A and C, B and C, or A and B and C, where any such combination may include one or more members of A, B, or C. All structural and functional equivalents to the elements of the various aspects described throughout the disclosure that are known or later become known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Furthermore, nothing disclosed herein is intended to be disclosed to the public, regardless of whether such disclosure is explicitly recited in the claims. Words such as "module," "mechanism," "element," "device," etc. cannot replace the word "component." Thus, no claim element will be construed as part-plus-function unless the element is explicitly stated using the phrase "component for..."

Claims

1. A method for wireless communication at a user equipment (UE), the method comprising: receiving, in a non-terrestrial network (NTN), a message indicating a feeder link switch from a source NTN entity to a target NTN entity and a time period associated with the switch; as well as A connection associated with the target NTN entity is established based on the time period.

2. The method of claim 1, wherein the message comprises one of a system information block (SIB) or a radio resource control (RRC) connection release message. The method of claim 2 , wherein the SIB comprises one of SIB3 or SIB19.

4. The method of claim 2, wherein the RRC connection release message includes redirection information, and wherein the connection is established further based on the redirection information.

5. The method according to claim 1, further comprising: The target NTN entity is identified based on information associated with the target NTN entity included in the message, wherein the connection is established further based on the information associated with the target NTN entity.

6. The method of claim 1, wherein the time period comprises at least one of a first time period during which the handover occurs or a second time period available for the target NTN entity to establish the connection, the second time period being offset from the first time period.

7. The method of claim 1 , wherein establishing the connection associated with the target NTN entity based on the time period comprises: sending a request for radio resource control (RRC) connection reestablishment to the target NTN entity based on the time period; as well as The connection associated with the target NTN entity is reestablished based on the request.

8. The method according to claim 1, further comprising: Reporting of a radio link failure (RLF) associated with the source NTN entity is avoided based on the message.

9. The method of claim 8, wherein the message further comprises an indication that the handover is associated with the RLF, and wherein the avoiding reporting the RLF is based on the indication that the handover is associated with the RLF.

10. The method of claim 8, wherein avoiding reporting the RLF comprises: detecting said RLF associated with said source NTN entity; as well as Sending a report indicating the RLF is avoided based on the message.

11. The method of claim 8, wherein avoiding reporting the RLF comprises: Detection of the RLF associated with the source NTN entity is avoided based on the message.

12. The method of claim 1, wherein when a configuration associated with a conditional handover of the UE from the source NTN entity to the target NTN entity has been received from the source NTN entity, establishing the connection is further based on the conditional handover.

13. A method of wireless communication at a source non-terrestrial network (NTN) entity, the method comprising: determining a first time period associated with a handover of a feeder link from the source NTN entity to a target NTN entity; as well as A message indicating the switching of the feeder link is sent based on the first time period, the message further indicating a second time period associated with availability of the target NTN entity.

14. The method of claim 13, wherein the message comprises one of a system information block (SIB) or a radio resource control (RRC) connection release message. The method of claim 14 , wherein the SIB comprises one of SIB3 or SIB19.

16. The method of claim 14, wherein the RRC connection release message includes redirection information identifying the target NTN entity.

17. The method according to claim 13, further comprising: A respective context associated with each user equipment (UE) in a group of user equipments (UE) having a connection with the source NTN entity during the first time period is sent to the target NTN entity in a single message.

18. The method according to claim 13, further comprising: Prior to the second time period, a handover of each user equipment (UE) in a group of user equipments (UEs) to the target NTN entity is performed based on the switching of the feeder link associated with the first time period.

19. The method according to claim 18, further comprising: A configuration associated with a conditional handover to the target NTN entity is sent to at least one UE in the group of UEs, wherein the at least one UE in the group of UEs is handed over to the target NTN entity based on the configuration.

20. The method of claim 13, wherein the second time period is offset from the first time period.

21. The method of claim 13, wherein the message further includes an indication that the handover is associated with a radio link failure (RLF).

22. A method for wireless communication at a target non-terrestrial network (NTN) entity, the method comprising: obtaining the feeder link in a first time period based on a switching of the feeder link from a source NTN entity; as well as A respective connection is established with each of a group of user equipments (UEs) connected to the source NTN entity during the first time period based on a second time period indicated to each of the group of UEs in a message from the source NTN entity.

23. The method according to claim 22, further comprising: Respective contexts associated with each UE in the set of UEs are received from the source NTN entity, each UE in the set of UEs having a connection with the source NTN entity during the first time period.

24. The method of claim 23, wherein the contexts respectively associated with the group of UEs are received in a single message from the source NTN entity.

25. The method according to claim 23, further comprising: Information associated with the switching of a feeder link from the source NTN entity to the target NTN entity is communicated over an Xn interface.

26. The method of claim 25, wherein the information associated with the feeder link switching comprises at least one of: the first time period during which the feeder link switching occurs, the second time period available to the target NTN entity, or an indication of whether the feeder link switching is associated with a radio link failure.

27. The method according to claim 22, further comprising: Prior to the second time period, a handover of each UE in the group of UEs from the source NTN entity is performed based on the switching of the feeder link.

28. The method of claim 27, wherein the handover is based on a configuration associated with a conditional handover from the source NTN entity, wherein at least one UE in the group of UEs is handed over from the source NTN entity based on the configuration.

29. The method of claim 22, wherein the second time period is offset from the first time period.

30. The method of claim 22, wherein establishing a corresponding connection with each UE in the group of UEs handed over from the source NTN entity based on the second time period indicated to each UE in the group of UEs in the message from the source NTN entity comprises: receiving, from each UE in the set of UEs, a respective request for a radio resource control (RRC) connection reestablishment based on the second time period; as well as The corresponding connection is reestablished with each UE in the group of UEs based on the corresponding request.

31. An apparatus for wireless communication at a user equipment (UE), the apparatus comprising: Memory; and at least one processor coupled to the memory and configured to: receiving, in a non-terrestrial network (NTN), a message indicating a feeder link switch from a source NTN entity to a target NTN entity and a time period associated with the switch; as well as A connection associated with the target NTN entity is established based on the time period.

32. The apparatus of claim 31, wherein the message comprises one of a system information block (SIB) or a radio resource control (RRC) connection release message.

33. The device of claim 32, wherein the SIB comprises one of SIB3 or SIB19.

34. The apparatus of claim 32, wherein the RRC connection release message includes redirection information, and wherein the connection is established further based on the redirection information.

35. The apparatus of claim 31 , wherein the at least one processor is further configured to: The target NTN entity is identified based on information associated with the target NTN entity included in the message, wherein the connection is established further based on the information associated with the target NTN entity.

36. The apparatus of claim 31, wherein the time period comprises at least one of a first time period during which the handover occurs or a second time period available for the target NTN entity to establish the connection, the second time period being offset from the first time period.

37. The apparatus of claim 31 , wherein establishing the connection associated with the target NTN entity based on the time period comprises: sending a request for radio resource control (RRC) connection reestablishment to the target NTN entity based on the time period; as well as The connection associated with the target NTN entity is reestablished based on the request.

38. The apparatus of claim 31 , wherein the at least one processor is further configured to: Reporting of a radio link failure (RLF) associated with the source NTN entity is avoided based on the message.

39. The apparatus of claim 38, wherein the message further comprises an indication that the handover is associated with the RLF, and wherein the avoiding reporting the RLF is based on the indication that the handover is associated with the RLF.

40. The apparatus of claim 38, wherein refraining from reporting the RLF comprises: detecting said RLF associated with said source NTN entity; as well as Sending a report indicating the RLF is avoided based on the message.

41. The apparatus of claim 38, wherein refraining from reporting the RLF comprises: Detection of the RLF associated with the source NTN entity is avoided based on the message.

42. The apparatus of claim 31, wherein when a configuration associated with a conditional handover of the UE from the source NTN entity to the target NTN entity has been received from the source NTN entity, the connection is established further based on the conditional handover.

43. An apparatus for wireless communication at a source non-terrestrial network (NTN) entity, the apparatus comprising: Memory; and at least one processor coupled to the memory and configured to: determining a first time period associated with a handover of a feeder link from the source NTN entity to a target NTN entity; and A message indicating the switching of the feeder link is sent based on the first time period, the message further indicating a second time period associated with availability of the target NTN entity.

44. The apparatus of claim 43, wherein the message comprises one of a system information block (SIB) or a radio resource control (RRC) connection release message.

45. The device of claim 44, wherein the SIB comprises one of SIB3 or SIB19.

46. ​​The apparatus of claim 44, wherein the RRC connection release message includes redirection information identifying the target NTN entity.

47. The apparatus of claim 43, wherein the at least one processor is further configured to: A respective context associated with each user equipment (UE) in a group of user equipments (UE) having a connection with the source NTN entity during the first time period is sent to the target NTN entity in a single message.

48. The apparatus of claim 43, wherein the at least one processor is further configured to: Prior to the second time period, a handover of each user equipment (UE) in a group of user equipments (UEs) to the target NTN entity is performed based on the switching of the feeder link associated with the first time period.

49. The apparatus of claim 48, wherein the at least one processor is further configured to: A configuration associated with a conditional handover to the target NTN entity is sent to at least one UE in the group of UEs, wherein the at least one UE in the group of UEs is handed over to the target NTN entity based on the configuration.

50. The apparatus of claim 43, wherein the second time period is offset from the first time period.

51. The apparatus of claim 43, wherein the message further comprises an indication that the handover is associated with a radio link failure (RLF).

52. An apparatus for wireless communication at a target non-terrestrial network (NTN) entity, the apparatus comprising: Memory; and at least one processor coupled to the memory and configured to: obtaining the feeder link in a first time period based on a switching of the feeder link from a source NTN entity; as well as A respective connection is established with each of a group of user equipments (UEs) connected to the source NTN entity during the first time period based on a second time period indicated to each of the group of UEs in a message from the source NTN entity.

53. The apparatus of claim 52, wherein the at least one processor is further configured to: Respective contexts associated with each UE in the set of UEs are received from the source NTN entity, each UE in the set of UEs having a connection with the source NTN entity during the first time period.

54. The apparatus of claim 53, wherein the contexts respectively associated with the group of UEs are received in a single message from the source NTN entity.

55. The apparatus of claim 53, wherein the at least one processor is further configured to: Information associated with the switching of a feeder link from the source NTN entity to the target NTN entity is communicated over an Xn interface.

56. The apparatus of claim 55, wherein the information associated with the feeder link switching comprises at least one of: the first time period during which the feeder link switching occurs, the second time period available to the target NTN entity, or an indication of whether the feeder link switching is associated with a radio link failure.

57. The apparatus of claim 52, wherein the at least one processor is further configured to: Prior to the second time period, a handover of each UE in the group of UEs from the source NTN entity is performed based on the switching of the feeder link.

58. The apparatus of claim 57, wherein the handover is based on a configuration associated with a conditional handover from the source NTN entity, wherein at least one UE in the group of UEs is handed over from the source NTN entity based on the configuration.

59. The apparatus of claim 52, wherein the second time period is offset from the first time period.

60. The apparatus of claim 52, wherein establishing a respective connection with each UE in the group of UEs handed over from the source NTN entity based on the second time period indicated to each UE in the group of UEs in the message from the source NTN entity comprises: receiving, from each UE in the set of UEs, a respective request for a radio resource control (RRC) connection reestablishment based on the second time period; as well as The corresponding connection is reestablished with each UE in the group of UEs based on the corresponding request.

61. An apparatus for wireless communication at a user equipment (UE), the apparatus comprising: means for receiving, in a non-terrestrial network (NTN), a message indicating a switch of a feeder link from a source NTN entity to a target NTN entity and a time period associated with said switch; and Means for establishing a connection associated with the target NTN entity based on the time period.

62. The apparatus of claim 61, wherein the message comprises one of a system information block (SIB) or a radio resource control (RRC) connection release message.

63. The device of claim 62, wherein the SIB comprises one of SIB3 or SIB19.

64. The apparatus of claim 62, wherein the RRC connection release message includes redirection information, and wherein the connection is established further based on the redirection information.

65. The apparatus of claim 61, further comprising: means for identifying the target NTN entity based on information associated with the target NTN entity included in the message, wherein the connection is established further based on the information associated with the target NTN entity.

66. The apparatus of claim 61, wherein the time period comprises at least one of a first time period during which the handover occurs or a second time period available for the target NTN entity to establish the connection, the second time period being offset from the first time period.

67. The apparatus of claim 61 , wherein the means for establishing the connection associated with the target NTN entity based on the time period is configured to: sending a request for a radio resource control (RRC) connection reestablishment to the target NTN entity based on the time period; and The connection associated with the target NTN entity is reestablished based on the request.

68. The apparatus of claim 61, further comprising: Means for avoiding reporting a radio link failure (RLF) associated with the source NTN entity based on the message.

69. The apparatus of claim 68, wherein the message further comprises an indication that the handover is associated with the RLF, and wherein the avoiding reporting the RLF is based on the indication that the handover is associated with the RLF.

70. The apparatus of claim 68, wherein the means for avoiding reporting the RLF is configured to: detecting the RLF associated with the source NTN entity; and Sending a report indicating the RLF is avoided based on the message.

71. The apparatus of claim 68, wherein the means for avoiding reporting the RLF is configured to: Detection of the RLF associated with the source NTN entity is avoided based on the message.

72. The apparatus of claim 61, wherein when a configuration associated with a conditional handover of the UE from the source NTN entity to the target NTN entity has been received from the source NTN entity, the connection is established further based on the conditional handover.

73. An apparatus for wireless communication at a source non-terrestrial network (NTN) entity, the apparatus comprising: means for determining a first time period associated with a handover of a feeder link from said source NTN entity to a target NTN entity; and Means for sending a message indicating the switching of the feeder link based on the first time period, the message further indicating a second time period associated with availability of the target NTN entity.

74. The apparatus of claim 73, wherein the message comprises one of a system information block (SIB) or a radio resource control (RRC) connection release message.

75. The device of claim 74, wherein the SIB comprises one of SIB3 or SIB19.

76. The apparatus of claim 74, wherein the RRC connection release message includes redirection information identifying the target NTN entity.

77. The apparatus of claim 73, further comprising: Means for sending, in a single message, to the target NTN entity, respective contexts associated with each user equipment (UE) in a group of user equipments (UE) having a connection with the source NTN entity during the first time period.

78. The apparatus of claim 73, further comprising: Means for performing a handover of each user equipment (UE) in a group of user equipments (UEs) to the target NTN entity based on the switching of the feeder link associated with the first time period prior to the second time period.

79. The apparatus of claim 78, further comprising: Means for sending a configuration associated with a conditional handover to the target NTN entity to at least one UE in the group of UEs, wherein the at least one UE in the group of UEs is handed over to the target NTN entity based on the configuration.

80. The apparatus of claim 73, wherein the second time period is offset from the first time period.

81. The apparatus of claim 73, wherein the message further comprises an indication that the handover is associated with a radio link failure (RLF).

82. An apparatus for wireless communication at a target non-terrestrial network (NTN) entity, the apparatus comprising: means for obtaining a feeder link during a first time period based on a switching of the feeder link from a source NTN entity; and Means for establishing a respective connection with each of a group of user equipments (UEs) connected to the source NTN entity during the first time period based on a second time period indicated to each of the group of user equipments (UEs) connected to the source NTN entity in a message from the source NTN entity.

83. The apparatus of claim 82, further comprising: Means for receiving, from the source NTN entity, respective contexts associated with each UE in the set of UEs, each UE in the set of UEs having a connection with the source NTN entity during the first time period.

84. The apparatus of claim 83, wherein the contexts respectively associated with the group of UEs are received in a single message from the source NTN entity.

85. The apparatus of claim 83, further comprising: Means for communicating information associated with a feeder link switch from said source NTN entity to said target NTN entity over an Xn interface.

86. The apparatus of claim 85, wherein the information associated with the feeder link switching comprises at least one of: the first time period during which the feeder link switching occurs, the second time period available to the target NTN entity, or an indication of whether the feeder link switching is associated with a radio link failure.

87. The apparatus of claim 82, further comprising: Means for performing a handover of each UE in the group of UEs from the source NTN entity based on the switching of the feeder link before the second time period.

88. The apparatus of claim 87, wherein the handover is based on a configuration associated with a conditional handover from the source NTN entity, wherein at least one UE in the group of UEs is handed over from the source NTN entity based on the configuration.

89. The apparatus of claim 82, wherein the second time period is offset from the first time period.

90. The apparatus of claim 82, wherein the means for establishing a respective connection with each UE in the group of UEs handed over from the source NTN entity based on the second time period indicated to each UE in the group of UEs in the message from the source NTN entity is configured to: receiving, from each UE in the set of UEs, a respective request for a radio resource control (RRC) connection re-establishment based on the second time period; and The corresponding connection is reestablished with each UE in the group of UEs based on the corresponding request.

91. A computer readable medium storing computer executable code for wireless communication at a user equipment (UE), the code when executed by a processor causing the processor to: receiving, in a non-terrestrial network (NTN), a message indicating a feeder link switch from a source NTN entity to a target NTN entity and a time period associated with the switch; and A connection associated with the target NTN entity is established based on the time period.

92. A computer readable medium storing computer executable code for wireless communication at a source non-terrestrial network (NTN) entity, which when executed by a processor causes the processor to: determining a first time period associated with a handover of a feeder link from the source NTN entity to a target NTN entity; and A message indicating the switching of the feeder link is sent based on the first time period, the message further indicating a second time period associated with availability of the target NTN entity.

93. A computer readable medium storing computer executable code for wireless communication at a target non-terrestrial network (NTN) entity, the code when executed by a processor causing the processor to: obtaining the feeder link during a first time period based on a switching of the feeder link from a source NTN entity; and A respective connection is established with each of a group of user equipments (UEs) connected to the source NTN entity during the first time period based on a second time period indicated to each of the group of UEs in a message from the source NTN entity.

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