Conditional handover for non-terrestrial networks

Abstract

A UE can perform location-based conditional handover (CHO) based on area information and size parameters associated with serving cells of a non-terrestrial network (NTN). In time-based CHO, the UE can perform CHO in response to expiration of a wait time configured by the network. Alternatively, the UE can perform CHO by randomly selecting a wait time from a range of times configured by the network. The selection can be randomized using a seed provided by the network or using a cell radio network temporary identifier (RNTI) value. In elevation-based CHO, the UE can perform CHO in response to an elevation angle of a satellite being less than a threshold configured by the network. When the UE is configured with multiple cells of the NTN and CHO criteria are satisfied for two or more of the cells, the UE can select a target cell for CHO based on prioritization of the cells indicated by the network.

Description

Technical Field

[0001] This disclosure relates to the field of wireless communications, and more specifically, to a mechanism for performing conditional handover in non-terrestrial networks. Background Technology

[0002] In non-terrestrial networks (NTNs), user equipment (UEs) can communicate with base stations via non-terrestrial platforms (NTPs), such as satellites, high-altitude platforms (HAPs), unmanned aerial vehicles (UAVs), or aircraft. The coverage area of ​​an NTN cell can move across the Earth's surface in response to the movement of the corresponding NTP (e.g., orbital motion). For example, when a UE is about to leave the coverage area of ​​its current serving cell due to satellite mobility, the UE may need to perform a handover from its current serving cell to a new cell. Therefore, a mechanism is needed to enable UE handover between NTN cells. Summary of the Invention

[0003] In some implementations, the User Equipment (UE) may be configured to receive area information and size parameters from a non-terrestrial network (NTN). The area information may indicate the area of ​​the serving cell associated with the non-terrestrial platform (NTP) of the NTN. The size parameters may indicate the size of the neighborhood of the area boundary. In response to determining that the UE's current location is within the neighborhood, the UE may perform a conditional handover (CHO) from the serving cell to the target cell of the NTN.

[0004] In some implementations, the user equipment (UE) can be configured to receive time information from a non-terrestrial network (NTN). This time information may be associated with a serving cell of the NTN. In response to receiving the time information, the UE can start a timer with a time value determined using the time information. In response to the expiration of the timer, the UE can perform a conditional handover (CHO) from the serving cell to a target cell of the NTN.

[0005] In some implementations, the time information may include an indication of a time value. Alternatively, the time information may include an indication of a random seed and a time range, wherein a time value is randomly selected from a timer range based on the random seed. As yet another alternative, the time information may include: a UE-specific random value; and an indication of a time range, wherein the time value is selected from a time range based on a UE-specific random value.

[0006] In some implementations, the user equipment (UE) may be configured to receive information indicating an elevation angle threshold for a non-terrestrial platform (NTP) associated with the currently serving cell of a non-terrestrial network (NTN). The UE can then determine the elevation angle of the NTP. In response to determining that the elevation angle is less than the elevation angle threshold, the UE can perform a conditional handover to the target cell of the NTN.

[0007] In some implementations, determining the elevation angle of the NTP may include: determining the NTP's position based on the NTP's ephemeris data; and determining the NTP's elevation angle based on the NTP's position and the UE's current position.

[0008] In some implementations, the User Equipment (UE) may be configured to receive configuration information, wherein, for each of a plurality of possible target cells in a non-terrestrial network (NTN), the configuration information indicates: (a) a corresponding priority level and (b) corresponding indication information defining the corresponding Conditional Handover (CHO) criteria. In response to determining that the CHO criteria of two or more possible target cells are met, the UE may select the cell with the highest priority level from the two or more possible target cells. The UE may then perform a conditional handover to the selected cell.

[0009] In some implementations, the non-transitory memory medium may store program instructions. When executed by the processing circuitry, the program instructions may cause the processing circuitry to perform any of the methods described above.

[0010] In some embodiments, the user equipment (UE) may include a wireless electronic system; processing circuitry coupled to the wireless electronic system; and a memory storing program instructions. When executed by the processing circuitry, the program instructions may cause the UE to perform any of the methods described in the embodiments above.

[0011] In some implementations, the non-transitory memory medium may store program instructions. When executed by the processing circuitry, the program instructions may cause the processing circuitry to perform any of the methods described above.

[0012] In some implementations, the base station may include a wireless electronic system; processing circuitry coupled to the wireless electronic system; and a memory storing program instructions. When executed by the processing circuitry, the program instructions may cause the base station to perform any of the methods described in the above implementations. Attached Figure Description

[0013] A better understanding of the subject matter can be obtained by considering the following detailed description of the preferred embodiments in conjunction with the accompanying drawings.

[0014] Figures 1 to 2 Examples of wireless communication systems according to some implementation schemes are shown.

[0015] Figure 3 Examples of base stations communicating with user equipment are shown according to some implementation schemes.

[0016] Figure 4 An exemplary block diagram of a user equipment (UE) device according to some implementation schemes is shown.

[0017] Figure 5 An exemplary block diagram of a base station according to some implementation schemes is shown.

[0018] Figure 6 An exemplary user equipment 600 according to some implementation schemes is shown.

[0019] Figure 7 An example of a base station 700 according to some implementation schemes is shown. The base station 700 can be used with... Figure 6 User equipment 600 communication.

[0020] Figure 8 Examples of methods for performing condition switching according to some implementation schemes are shown.

[0021] Figure 9A An example of a square area associated with conditional handover from a serving cell of a non-terrestrial network (NTN) is shown according to some implementation schemes.

[0022] Figure 9B The following are illustrated according to some implementation schemes. Figure 9A An example of the neighborhood (crossed shaded lines) of the boundary of a square region.

[0023] Figure 10A An example of a hexagonal region associated with conditional handover from a serving cell of an NTN is shown according to some implementation schemes.

[0024] Figure 10B The following are illustrated according to some implementation schemes. Figure 10A An example of the neighborhood of the boundary of a hexagonal region (crossed shaded lines).

[0025] Figure 11 An example of a location-based conditional handover method for performing communication with a non-terrestrial network for user equipment, according to some implementation schemes, is shown.

[0026] Figure 12 Examples of timer-based conditional handover methods for performing user equipment between cells in a non-terrestrial network, according to some implementation schemes, are shown.

[0027] Figure 13A Examples of elevation-based conditional handover methods for performing user equipment between cells in a non-terrestrial network, according to some implementation schemes, are shown.

[0028] Figure 13B Examples of elevation angles for non-land-based platforms (such as satellites) according to some implementation schemes are shown.

[0029] Figure 14AExamples of methods for operating user equipment (UE) based on one or more CHO criteria other than signal quality to facilitate conditional handover (CHO) in non-terrestrial networks are shown according to some implementations.

[0030] Figure 14B Examples of methods for operating a base station (BS) to facilitate conditional handover (CHO) of user equipment based on one or more CHO criteria other than signal quality, according to some implementation schemes, are shown.

[0031] Figure 15 An example of a scenario in which multiple satellites are configured for user equipment is shown, according to some implementation schemes.

[0032] Figure 16 Examples of methods for implementing a prioritization scheme for conditional handover among multiple possible target cells in a non-terrestrial network, according to some implementation schemes, are shown.

[0033] While the features described herein are susceptible to various modifications and alternatives, specific embodiments thereof are illustrated by way of example in the accompanying drawings and described in detail herein. However, it should be understood that the drawings and their detailed description are not intended to limit this document to the specific forms disclosed, but rather are intended to cover all modifications, equivalents, and alternatives falling within the substance and scope of the subject matter as defined by the appended claims. Detailed Implementation

[0034] acronym

[0035] The following acronyms are used in this disclosure:

[0036] 3GPP: Third Generation Partnership Project

[0037] 3GPP2: Third Generation Partnership Project 2

[0038] 5G NR: Fifth Generation New Radio

[0039] BW: Bandwidth

[0040] BWP: Bandwidth section

[0041] CA: Carrier Aggregation

[0042] CC: Component Carrier

[0043] CHO: Condition Switching

[0044] CSI: Channel State Information

[0045] CSI-RS: CSI Reference Signal

[0046] DCI: Downlink Control Information

[0047] DL: Downlink

[0048] DRB: Data Radio Bearer

[0049] eNB (or eNodeB): Evolved Node B, i.e., a 3GPP LTE base station.

[0050] EN-DC: E-UTRA-NR Dual Connection

[0051] E-UTRA: Evolved Universal Terrestrial Radio Access

[0052] FR n: Frequency range n

[0053] gNB (or gNodeB): Next-generation node B, i.e., 5G NR base station.

[0054] HARQ: Hybrid Automatic Repeat Request

[0055] LTE: Long Term Evolution

[0056] LTE-A: Advanced LTE

[0057] MAC: Media Access Control

[0058] MAC-CE: MAC control element

[0059] MIMO: Multiple Input Multiple Output

[0060] NR: New Radio

[0061] NR-DC: NR Dual Connection

[0062] NSA: Non-independent

[0063] NW: Network

[0064] PBCH: Physical Broadcast Channel

[0065] PDCCH: Physical Downlink Control Channel

[0066] PDCP: Packet Data Convergence Protocol

[0067] PDU: Protocol Data Unit

[0068] PDSCH: Physical Downlink Shared Channel

[0069] PRB: Physical Resource Block

[0070] QAM: Quadrature Amplitude Modulation

[0071] RAN: Radio Access Network

[0072] RAT: Radio Access Technology

[0073] RLC: Radio Link Control

[0074] RLM: Radio Link Monitoring

[0075] RNTI: Temporary Identifier for Radio Networks

[0076] RRC: Radio Resource Control

[0077] RRM: Radio Resource Management

[0078] RS: Reference signal

[0079] RTT: Round Trip Time

[0080] SCI: Sidelink Control Information

[0081] SN: serial number

[0082] SR: Scheduling Request

[0083] SSB: Synchronization Signal / PBCH Block

[0084] TB: Transport Block

[0085] UE: User Equipment

[0086] UL: Uplink

[0087] UMTS: Universal Mobile Telecommunication System

[0088] the term

[0089] The following is a glossary of terms used in this disclosure:

[0090] Memory media—any device of any type of memory device or storage device. The term “memory media” is intended to include mounting media such as CD-ROMs, floppy disks, or magnetic tape devices; computer system memory or random access memory such as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; non-volatile memory such as flash memory, magnetic media, such as hard disk drives or optical storage devices; registers, or other similar types of memory elements, etc. Memory media may also include other types of memory, or combinations thereof. Furthermore, memory media may reside in a first computer system executing a program, or may reside in a different second computer system connected to the first computer system via a network such as the Internet. In the latter case, the second computer system may provide program instructions to the first computer for execution. The term “memory media” may include two or more memory media that may reside in different locations on different computer systems connected via a network, for example. Memory media may store program instructions (e.g., representing a computer program) that can be executed by one or more processors.

[0091] Carrier medium—the memory medium as described above, and physical transmission medium, such as buses, networks and / or other physical transmission media for transmitting signals (such as electrical signals, electromagnetic signals or digital signals).

[0092] Programmable hardware elements encompass a variety of hardware devices that include multiple programmable functional blocks connected via programmable interconnects. Examples include FPGAs (Field-Programmable Gate Arrays), PLDs (Programmable Logic Devices), FPOAs (Field-Programmable Object Arrays), and CPLDs (Complex PLDs). Programmable functional blocks can vary from fine-grained (combinatorial logic units or lookup tables) to coarse-grained (arithmetic logic units or processor cores). Programmable hardware elements may also be referred to as "configurable logic units."

[0093] Computer system—any computing or processing system of all types, including personal computer systems (PCs), mainframe computer systems, workstations, network appliances, internet-connected appliances, personal digital assistants (PDAs), personal communication devices, smartphones, television systems, grid computing systems, or other devices or combinations thereof. In general, the term "computer system" can be broadly defined to encompass any device (or combination of devices) having at least one processor that executes instructions from a memory medium.

[0094] User equipment (UE) (or “UE device”) — any of a variety of computer system devices that are mobile or portable and perform wireless communications. Examples of UE devices include mobile phones or smartphones (e.g., iPhone). TMBased on Android TM Telephones (such as mobile phones) or satellite phones, portable gaming devices (such as Nintendo DS) TM PlayStation Portable TM Gameboy Advance TM iPhone TM Wearable devices (e.g., smartwatches, smart glasses), laptops, PDAs, portable networking devices, music players, data storage devices, or other handheld devices. Generally, the term "UE" or "UE device" can be broadly defined as any electronic, computing, and / or telecommunications equipment (or combination of equipment) that is easily transportable by the user and capable of wireless communication.

[0095] Base station - The term "base station" has the full range of its general meaning and includes at least a wireless communication station configured to wirelessly communicate with user equipment (UE) equipment and provide the UE equipment with access to a communication network.

[0096] Processing element—refers to any of a variety of elements or combinations of elements. Processing elements include, for example, circuitry such as ASICs (Application-Specific Integrated Circuits), portions or circuitry of individual processor cores, entire processor cores, individual processors, programmable hardware devices (such as Field-Programmable Gate Arrays (FPGAs)), and / or a large portion of a system comprising multiple processors.

[0097] Automatic—means an action or operation performed by a computer system (e.g., software executed by the computer system) or device (e.g., circuits, programmable hardware elements, ASICs, etc.) without requiring direct user input to specify or perform that action or operation. Therefore, the term "automatic" contrasts with an action performed or specified manually by a user, where the user provides input to directly perform that action. An automatic process can be initiated by user-provided input, but the subsequent actions performed "automatically" are not specified by the user; that is, they are not performed "manually," where the user specifies each action to be performed. For example, a user filling out a form by selecting each field and providing input to specify information (e.g., by typing information, selecting a checkbox, radio selection, etc.) is considered manually filling out the form, even though the computer system must update the form in response to the user's actions. The form can be automatically filled out by a computer system (e.g., software executed on the computer system) which analyzes the fields of the form and fills it out without any user input specifying answers for the fields. As indicated above, the user can invoke the automatic filling of the form but does not participate in the actual filling of the form (e.g., the user does not manually specify answers for the fields, but they are completed automatically). This manual provides various examples of operations that are automatically performed in response to actions taken by the user.

[0098] Figures 1 to 3 -Communication System

[0099] Figure 1 and Figure 2 An exemplary (and simplified) wireless communication system is shown. Note that... Figure 1 and Figure 2 The system described is merely an example of some possible systems, and various implementation schemes can be implemented in any of the various ways as needed.

[0100] Figure 1 The wireless communication system includes a base station 102A, which communicates with one or more user equipment (UE) devices 106A, 106B, etc., 106N via a transmission medium. Each of the user equipment devices may be referred to herein as a "user equipment" (UE). Figure 2 In the wireless communication system, in addition to base station 102A, base station 102B also (e.g., simultaneously or concurrently) communicates with UE devices 106A, 106B, etc. to 106N through a transmission medium.

[0101] Base stations 102A and 102B can be transceiver base stations (BTS) or cell sites, and may include hardware to enable wireless communication with user equipment 106A to 106N. Each base station 102 may also be configured to communicate with a core network 100 (e.g., base station 102A may be coupled to core network 100A, and base station 102B may be coupled to core network 100B), which may be the core network of a cellular service provider. Each core network 100 may also be coupled to one or more external networks (such as external network 108), which may include the Internet, the Public Switched Telephone Network (PSTN), or any other network. Therefore, base station 102A may facilitate communication between user equipment and / or between user equipment and network 100A; Figure 2 In the system, base station 102B can facilitate communication between user equipment and / or between user equipment and network 100B.

[0102] Base stations 102A and 102B can be configured to communicate with user equipment using any of the various radio access technologies (RATs) via a transmission medium. These radio access technologies are also known as wireless communication technologies or telecommunications standards, such as GSM, UMTS (WCDMA), LTE, LTE-A Advanced, 5G New Radio (NR), 3GPP 2CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), Wi-Fi, WiMAX, etc.

[0103] For example, base station 102A and core network 100A may operate according to a first cellular communication standard (e.g., 5G NR), while base station 102B and core network 100B may operate according to a second cellular communication standard. The second cellular communication standard (e.g., LTE, GSM, UMTS, and / or one or more CDMA2000 cellular communication standards) may be different from or the same as the first cellular communication standard. The two networks may be controlled by the same network operator (e.g., a cellular service provider or "operator") or different network operators. Furthermore, the two networks may operate independently of each other (e.g., if they operate according to different cellular communication standards), or they may operate in a manner that is either partially coupled or tightly coupled.

[0104] It should also be noted that, although in Figure 2 The network configuration shown illustrates the use of two different networks to support two different cellular communication technologies, but other network configurations implementing multiple cellular communication technologies are also possible. As an example, base stations 102A and 102B can operate according to different cellular communication standards but are coupled to the same core network. As another example, a multi-mode base station capable of simultaneously supporting different cellular communication technologies (e.g., 5G NR and LTE, LTE and CDMA 1xRTT, GSM and UMTS, or any other combination of cellular communication technologies) might be coupled to a core network that also supports different cellular communication technologies. Any other various network deployment scenarios are also possible.

[0105] As an alternative possibility, base stations 102A and 102B may also operate using the same wireless communication technology (or a set of overlapping wireless communication technologies). For example, base station 102A and core network 100A may be operated by a single cellular service provider independently of base station 102B and core network 100B, and the base stations and core network may be operated by different (e.g., competing) cellular service providers. Therefore, in this scenario, despite using similar and potentially compatible cellular communication technologies, UE devices 106A to 106N may communicate independently with base stations 102A to 102B, possibly by utilizing separate user identities to communicate with different operator networks.

[0106] UE 106 is capable of communicating using multiple wireless communication standards. For example, UE 106 can be configured to communicate using any one or two of the following 3GPP cellular communication standards (such as LTE) and / or 3GPP2 cellular communication standards (such as those in the CDMA2000 series). As another example, UE 106 can be configured to communicate using two or more different 3GPP cellular communication standards (such as GSM, UMTS, LTE, LTE-A, or 5G NR). Therefore, as described above, UE 106 can be configured to communicate with base station 102A (and / or other base stations) according to a first cellular communication standard (e.g., 5G NR), and can also be configured to communicate with base station 102B (and / or other base stations) according to a second cellular communication standard (e.g., LTE).

[0107] Base stations 102A and 102B, as well as other base stations, operating under the same or different cellular communication standards, can support one or more cell networks that can provide continuous or near-continuous overlapping services to UEs 106A to 106N and similar devices over a wide geographical area via one or more cellular communication standards.

[0108] UE 106 can also be configured, or alternatively configured, to communicate using WLAN, Bluetooth, one or more Global Navigation Satellite Systems (GNSS, such as GPS or GLONASS), one and / or more mobile television broadcasting standards (e.g., ATSC-M / H or DVB-H). Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible.

[0109] Figure 3 User equipment 106 (e.g., one of devices 106A to 106N) communicating with base station 102 (e.g., one of base stations 102A or 102B). UE 106 can be a device with wireless network connectivity, such as a mobile phone, handheld device, satellite phone, computer or tablet, wearable device, or substantially any type of wireless device. Base station 102 can be part of a non-terrestrial network. For example, base station 102 can be included in a non-terrestrial platform (NTP) that provides one or more cells for wireless communication with the UE. Alternatively, base station 102 can be located on or near the Earth's surface and configured to wirelessly communicate with one or more NTPs. The NTP can include platforms such as satellites, high-altitude platforms (HAPs), unmanned aerial vehicles (UAVs), etc.

[0110] The UE may include a processor configured to execute program instructions stored in memory. The UE can perform any of the method embodiments described herein by executing such stored instructions. Alternatively or additionally, the UE may include programmable hardware elements such as an FPGA (Field Programmable Gate Array) configured to perform any of the method embodiments described herein, or any portion thereof.

[0111] UE 106 can be configured to communicate using any of a number of wireless communication protocols. For example, UE 106 can be configured to communicate using two or more of the following: GSM, UMTS (W-DCMA, TD-SCDMA, etc.), CDMA2000 (1xRTT, 1xEV-DO, HRPD, eHRPD, etc.), LTE, LTE-A, 5G New Radio (NR), WLAN, or GNSS. Other combinations of wireless communication standards are also possible.

[0112] UE 106 may include one or more antennas (or one or more antenna arrays) for communicating using one or more wireless communication protocols. Within UE 106, one or more portions of the receive and / or transmit chain may be shared among multiple wireless communication standards; for example, UE 106 may be configured to communicate using a single shared radio component using one or both of LTE or 5G NR. The shared radio component may include a single antenna, or may include multiple antennas for performing wireless communication (e.g., for MIMO and / or beamforming). (MIMO is an acronym for Multiple-Input Multiple-Output.) Antennas may be organized into one or more arrays.

[0113] Figure 4 -Exemplary block diagram of UE

[0114] Figure 4An exemplary block diagram of UE 106 is shown. As shown, UE 106 may include a System-on-Chip (SOC) 300, which may include portions for various purposes. For example, as shown, SOC 300 may include a processor 302 capable of executing program instructions for UE 106 and display circuitry 304 capable of performing graphics processing and providing display signals to display 345. Processor 302 may also be coupled to a memory management unit (MMU) 340 and / or other circuitry or devices (such as display circuitry 304, radio components 330, connector I / F 320, and / or display 345), which may be configured to receive addresses from processor 302 and translate those addresses into locations in memory (e.g., memory 306, read-only memory (ROM) 350, NAND flash memory 310). MMU 340 may be configured to perform memory protection and page table translation or setup. In some embodiments, MMU 340 may be included as part of processor 302.

[0115] As shown in the figure, the SOC 300 can be coupled to various other circuits of the UE 106. For example, the UE 106 may include various types of memory (e.g., including flash memory 310), connector interface 320 (e.g., for coupling to computer systems, docking stations, charging stations, etc.), display 345, and radio components 330.

[0116] Radio component 330 may include one or more RF chains. Each RF chain may include a transmit chain, a receive chain, or both. For example, radio component 330 may include two RF chains to support dual connectivity with two base stations (or two cells). Radio component may be configured to support wireless communication according to one or more wireless communication standards, such as GSM, UMTS, LTE, LTE-A, 5G NR, WCDMA, CDMA2000, Bluetooth, Wi-Fi, GPS, etc.

[0117] Radio component 330 is coupled to antenna subsystem 335, which includes one or more antennas. For example, antenna subsystem 335 may include multiple antennas (e.g., organized into one or more arrays) to support applications such as dual-connectivity, MIMO, or beamforming. Antenna subsystem 335 transmits and receives radio signals to / from one or more base stations or devices via a radio propagation medium.

[0118] In some implementations, processor 302 may include a baseband processor to generate uplink baseband signals and / or process downlink baseband signals. Processor 302 may be configured to perform data processing according to one or more of one or more wireless communication standards, such as GSM, UMTS, LTE, LTE-A, 5G NR, WCDMA, CDMA2000, Bluetooth, Wi-Fi, GPS, etc.

[0119] UE 106 may also include one or more user interface elements. User interface elements may include various components such as display 345 (which may be a touch screen display), keyboard (which may be a separate keyboard or may be implemented as part of the touch screen display), mouse, microphone and / or speaker, one or more cameras, one or more sensors, one or more buttons, sliders and / or dial pads, and / or any of various other components capable of providing information to the user and / or receiving or interpreting user input.

[0120] As shown in the figure, UE 106 may also include one or more User Identity Modules (SIMs) 360. Each of the one or more SIMs may be implemented as an embedded SIM (eSIM), in which case the SIM may be implemented in device hardware and / or software. For example, in some embodiments, UE 106 may include an embedded UICC (eUICC), for example, a device built into UE 106 and not removable. The eUICC may be programmable, such that one or more eSIMs may be implemented on the eUICC. In other embodiments, the eSIM may be installed in the UE 106 software, for example, as program instructions stored on a storage medium (such as memory 306 or flash memory 310) that executes on a processor (such as processor 302) in UE 106. As an example, SIM 360 may be an application that executes on a Universal Integrated Circuit Card (UICC). Alternatively or otherwise, one or more of the SIMs 360 may be implemented as removable SIM cards.

[0121] The processor 302 of the UE device 106 may be configured to implement some or all of the methods described herein, for example, by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). In other embodiments, the processor 302 may be configured as or include: a programmable hardware element such as a FPGA (Field Programmable Gate Array); or an ASIC (Application-Specific Integrated Circuit); or a combination thereof.

[0122] Figure 5 - Example of a base station

[0123] Figure 5 A block diagram of base station 102 is shown. Note that... Figure 5The base station shown is merely one example of a possible base station. As illustrated, base station 102 may include a processor 404 capable of executing program instructions specific to base station 102. Processor 404 may also be coupled to a memory management unit (MMU) 440 or other circuitry or device, which may be configured to receive addresses from processor 404 and translate those addresses into locations in memory (e.g., memory 460 and read-only memory (ROM) 450).

[0124] Base station 102 may include at least one network port 470. Network port 470 may be configured to be coupled to a telephone network and provide services (as described above) to multiple devices such as UE device 106. Figure 1 and Figure 2 Access to the telephone network as described in the document.

[0125] Network port 470 (or an additional network port) may also be configured, or alternatively configured, to be coupled to a cellular network, such as the core network of a cellular service provider. The core network may provide mobility-related services and / or other services to various devices, such as UE device 106. In some cases, network port 470 may be coupled to a telephone network via the core network, and / or the core network may provide telephone services (e.g., in UE devices served by a network provider).

[0126] Base station 102 may include radio components 430 having one or more RF chains. Each RF chain may include a transmit chain, a receive chain, or both. (For example, base station 102 may include at least one RF chain per sector or cell). Radio components 430 are coupled to antenna subsystem 434, which includes one or more antennas, or one or more antenna arrays. For example, multiple antennas are required to support applications such as MIMO and / or beamforming. Antenna subsystem 434 transmits and receives radio signals to and from the UE via a radio propagation medium.

[0127] In some implementations, processor 404 may include a baseband processor to generate downlink baseband signals and / or process uplink baseband signals. The baseband processor may be configured to operate according to one or more wireless telecommunications standards, including but not limited to GSM, LTE, 5G New Radio, WCDMA, CDMA2000, etc.

[0128] The processor 404 of base station 102 may be configured to implement any of the methods described herein, for example, by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). In some embodiments, processor 404 may include: programmable hardware elements such as FPGA (Field Programmable Gate Array); or ASIC (Application-Specific Integrated Circuit); or combinations thereof.

[0129] In some implementations, the wireless user equipment (UE) device 600 can be as follows: Figure 6 The configuration is shown. UE device 600 may include: a wireless electronic system 605 for performing wireless communication; and a processing element 610 operatively coupled to the wireless electronic system. (UE device 600 may also include any subset of the UE features described above, for example, in combination with...) Figures 1 to 4 ).

[0130] The wireless electronic system 605 may include one or more RF chains, such as those described above. Each RF chain may be configured to receive signals from a radio propagation channel and / or transmit these signals onto the radio propagation channel. Therefore, each RF chain may include a transmit chain and / or a receive chain. The wireless electronic system 605 may be coupled to one or more antennas (or one or more antenna arrays) to facilitate signal transmission and reception. Each transmit chain (or several transmit chains) may be tuned to a desired frequency, thereby allowing the transmit chain to transmit at different frequencies at different times. Similarly, each receive chain (or several receive chains) may be tuned to a desired frequency, thereby allowing the receive chain to receive at different frequencies at different times.

[0131] Processing element 610 may be coupled to a wireless electronic system and may be configured as described in the various descriptions above. (For example, the processing element may be implemented by processor 302). The processing element may be configured to control the state of each RF chain in the wireless electronic system. The processing element may be configured to perform any of the base station-based method implementations described herein.

[0132] In some implementations, the processing element may include one or more baseband processors to (a) generate baseband signals to be transmitted by the wireless electronic system and / or (b) process baseband signals provided by the wireless electronic system.

[0133] In dual-connectivity operation mode, the processing element can instruct a first RF chain to communicate with a first base station using a first radio access technology, and instruct a second RF chain to communicate with a second base station using a second radio access technology. For example, the first RF chain can communicate with an LTE eNB, and the second RF chain can communicate with a 5G New Radio (NR) gNB. A link with an LTE eNB can be referred to as an LTE branch. A link with a gNB can be referred to as an NR branch. In some embodiments, the processing element may include a first sub-circuit implementing baseband processing relative to the LTE branch and a second sub-circuit implementing baseband processing relative to the NR branch.

[0134] The processing element 610 may be further configured as described in various sections below.

[0135] UE device 600 may include memory (e.g., in conjunction with the above). Figure 6The user equipment 106 may contain any of the memories described herein, or any combination of such memories, which store program instructions for implementing any UE method implementation described herein, such as program instructions to be executed by processing element 610. In some embodiments, the memory may store instructions for receiving and processing... Figure 8 The reconfiguration message 814 contains program instructions, such as those described above.

[0136] In some implementations, the wireless base station 700 of the wireless network (not shown) can be as follows: Figure 7 The configuration is shown. A wireless base station may include: a wireless subsystem 705 for performing wireless communication via a radio propagation channel; and a processing element 710 operatively coupled to the wireless subsystem. (The wireless base station may also include any subset of the base station features described above, for example, those combined with the above description.) Figure 5 (The aforementioned features). A wireless base station can host one or more cells. For example, in the context of a non-terrestrial network, a wireless base station can be included in a non-terrestrial platform, such as a satellite, or HAP, or UAV, or aircraft. Alternatively, the wireless base station can be located on or near the Earth's surface and configured to wirelessly communicate with one or more NTPs, each of which mediates a corresponding set of one or more cells.

[0137] The wireless electronic system 705 may include one or more RF chains. Each transmit / receive chain may be tunable to a desired frequency, allowing the transmit / receive chain to transmit / receive at different frequencies at different times. The wireless electronic system 705 may be coupled to an antenna subsystem, which includes one or more antennas, such as an antenna array or multiple antenna arrays. The wireless electronic system may employ the antenna subsystem to transmit radio signals to and from a radio wave propagation medium.

[0138] Processing element 710 may be implemented as described in the various descriptions above. For example, in one embodiment, processing element 710 may be implemented as processor 404. In some embodiments, processing element may include one or more baseband processors to: (a) generate baseband signals to be transmitted by the wireless electronic system, and / or (b) process baseband signals provided by the wireless electronic system.

[0139] The processing element 710 can be configured to perform any of the base station method implementations described herein.

[0140] Base station 700 may include a memory (e.g., Figure 5The base station 102 may have a memory 460 (or some other memory) storing program instructions for implementing any of the base station method embodiments described herein, such as program instructions to be executed by the processing element 710. In some embodiments, the memory may store instructions for writing and transmitting... Figure 8 The reconfiguration message 814 contains program instructions, such as those described above.

[0141] Conditional switching for non-terrestrial networks

[0142] User equipment (UE) can communicate with cells of a non-terrestrial network (NTN). For example, a UE can communicate with cells generated by one or more non-terrestrial platforms, such as satellites, unmanned aerial vehicles (UAVs), high-altitude platforms (HAPs), aircraft, etc. The base station hosting the cell can be based on a terrestrial and / or non-terrestrial platform. Thus, in some embodiments, a non-terrestrial platform can: receive data from a terrestrial base station and forward the data to a terrestrial UE via downlink transmission; and receive data from the UE via uplink transmission and forward the data to the terrestrial base station. (It should be noted that when using the term "terrestrial," it does not require the entity to be fixed. For example, a terrestrial base station can be located on a train or ship.) In other embodiments, the base station is included as part of a non-terrestrial platform that can receive data from a terrestrial network node of the communication network and forward the data to the UE via downlink transmission; and receive data from the UE and forward the data to the terrestrial network node.

[0143] In some implementations, the UE may be on or near the Earth's surface. In other implementations, the UE may be located above the Earth's surface, such as on an aircraft or a high-altitude platform (HAP).

[0144] The coverage area of ​​each cell can move across the Earth's surface. Therefore, even if the UE is not moving, it will enter and exit the coverage areas of different cells at different times. Thus, when the UE leaves the coverage area of ​​the first cell, it will need to perform a handover from the first cell to the second cell. The UE can be configured to perform a conditional handover from one cell to another in response to determining that one or more network configuration conditions are met.

[0145] In some implementations, the non-terrestrial platform may include one or more antenna arrays to facilitate uplink and / or downlink beamforming. The non-terrestrial platform may include one or more solar panel arrays to power the operation of the NTP and includes batteries to store the power generated by the solar panels. Non-terrestrial platforms, such as satellites, may include mechanisms for adjusting their attitude and / or position.

[0146] In some implementations, components in the non-terrestrial network can perform conditional switching procedures, for example, such as Figure 8 As shown. User Equipment (UE) 802 can transmit user data to / from source gNB 804, and the source gNB can transmit user data to / from one or more User Plane Functions (UPFs) 812. At step 0, mobility control information can be provided by Access and Mobility Management Function (AMF) 810. Mobility control information can be provided to the source gNB, for example, using the restrictionType attribute of the ALLOWED_AREAS field. At step 1, the source gNB can configure the measurement procedure to be performed by the UE; and the UE can report the measurement results to the source gNB according to the measurement configuration. At step 2, the source gNB can decide to adopt a conditional handover (CHO). Since the source gNB may not be able to predict which other gNB the UE will select for conditional handover, the source gNB can prepare multiple candidate gNBs for conditional handover.

[0147] At step 3, the source gNB may send a conditional handover request (handover request) to one or more candidate cells associated with one or more candidate gNBs. The candidate gNBs are described as including target gNB 806 and one or more other possible target gNBs 808. Each candidate gNB may perform step 4 of the admission control (e.g., as described in 3GPP TS 38.300), in response to which the candidate gNB may send an acknowledgment of the conditional handover request (referred to as a handover request acknowledgment) to the source gNB. At step 5, the acknowledgment sent by the candidate gNB may include the configuration of one or more CHO candidate cells associated with (or mediated by) the candidate gNB. In some implementations, an acknowledgment message may be sent for each candidate cell.

[0148] In response to receiving confirmation, the source gNB may transmit a reconfiguration message 814 to the UE, such as a reconfiguration message for the RRC protocol. (RRC is an acronym for Radio Resource Control.) The reconfiguration message may include a reconfiguration measurement index. In different implementations, the content of the reconfiguration message and the reconfiguration measurement index may differ. The reconfiguration message may include the configuration of the candidate gNB's CHO candidate cells and the corresponding conditions for CHO execution.

[0149] In response to receiving a reconfiguration message (including reconfiguring the measurement index), the UE may, for example, transmit a reconfiguration complete message 816 using the RRC protocol. In response to receiving the reconfiguration complete message, for example, if early data forwarding is to be applied, the source gNB may transmit an early state transmission message to the target gNB 806 and / or other possible target gNB 808 (at step 7a). (The UE may be configured to evaluate the CHO conditions for the target gNB before evaluating the CHO conditions for other possible target gNBs.) After transmitting the early state transmission message, the source gNB may forward user data from the UPF to the target gNB (and / or other possible gNBs).

[0150] Upon receiving a reconfiguration message, the UE can maintain its current connection with the source gNB and evaluate one or more conditional switching conditions for each candidate cell, as shown at 818. (One or more CHO conditions may be indicated or defined by the reconfiguration message and / or the reconfiguration measurement index.) In response to determining that one of the candidate cells satisfies the corresponding condition of the CHO, the UE can designate the determined candidate cell as the target cell, separate it from existing cells, apply the corresponding stored configuration to the target cell, and synchronize with the target cell, as indicated at 820. Figure 8 In this context, it is assumed that the target cell is the cell of target gNB 806. Although the target cell is usually a single candidate, for the purpose of waiting time, the target cell may be associated with any of the candidate gNBs (e.g., one of the possible target gNBs 808).

[0151] At step 8, the conditional handover is completed. For example, the UE can complete the conditional handover process by sending a reconfiguration completion message (not shown) to the target gNB, such as an RRC reconfiguration completion message.

[0152] At step 8a, the target gNB may send a handover success message to the source gNB to notify the source gNB that the UE has successfully accessed the target cell. At step 8b, the source gNB may send an SN status transmission message to the target gNB. (SN is an abbreviation for source / secondary node. For example, in the context of this invention, the source gNB is SN.) At step 8c, the target gNB may send a handover cancellation message to target gNB 806 and other possible target gNBs. After the SN status transmission or handover cancellation message, the target gNB can receive user data from the network and forward the user data to the UE; and receive user data from the UE and forward the user data to the network.

[0153] If the evaluation of one or more CHO conditions fails, the source gNB can forward the user data to another possible gNB and perform a new switch (e.g., condition switch) to one of the other possible target gNBs.

[0154] In various implementation schemes, Figure 8 One or more steps shown may be omitted and / or performed in a different order than shown. Furthermore, one or more steps may be added. For example, in some embodiments, steps 9 through 12 of Figure 9.2.3.2.1-1 of 3GPP TS 38.300 may be added after step 8c, for example. (TS is an acronym for Technical Specification.)

[0155] Location-based conditional switching

[0156] In some implementations, the UE can perform location-based conditional handover between NTN cells as follows: The non-terrestrial platform (NTP) can transmit area information to the UE. (For example, the NTP corresponding to the current serving cell can transmit area information.) The area information indicates or defines the area of ​​the current serving cell, i.e., an area on the Earth's surface. (The term "Earth's surface" will be interpreted broadly and includes land surfaces and lake / ocean / sea surfaces.) This area can be the coverage area of ​​the serving cell or a portion of the serving cell's coverage area. (More generally, the area information can define the coverage area or area of ​​one or more cells (e.g., cells known to be near the UE's current location by the network). The area information may include the coordinates (e.g., GNSS coordinates) of the vertices of a polygon on the Earth's surface. GNSS is an acronym for Global Navigation Satellite System. For example, the area information may include the GNSS coordinates of vertices V1 to V4 of a square, such as... Figure 9A As shown. The polygon can be a rectangle, pentagon, hexagon, or N-polygon, where N is greater than or equal to 3. (The term "N-polygon" refers to a polygon with N sides.) The polygon can correspond to the cell coverage area (or a portion of the cell coverage area) at a specific time (e.g., the current time or a future time). The NTP can send updates of the area information to the UE over time.

[0157] NTP can also transmit size parameters along with region information. These size parameters can indicate the width or radius of the neighborhood of the region's boundary polygon. For example, in... Figure 9A In the case of a square region, the size parameter can indicate the radius R of the neighborhood including the boundary square. Therefore, if the boundary square has a side length L, the neighborhood of the boundary square can be interpreted as the region defined by squares with side length L+2R and squares with side length L-2R (shown as crosshairs), such as... Figure 9BAs shown, both have the same center as the square with side length L.

[0158] As another example, in the case of a hexagonal region, the region information may include vertices V1 to V6, such as... Figure 10A As shown. The size parameter can define a neighborhood comprising the radius R (or width 2R) of the hexagonal boundary of the region. (Although the boundary hexagon is depicted as a regular hexagon, non-regular hexagons can also be used.) Figure 10B As shown, the neighborhood indicated by the cross-shading can be the set of points on the Earth's surface that are less than (or less than or equal to) R from the boundary of the hexagon.

[0159] In some implementations, the UE may use a GPS receiver to determine its current location. The UE may then determine whether the current location is within a boundary neighborhood. If the current location is within the neighborhood, the UE may determine whether one or more additional CHO conditions are met. These additional CHO conditions may include one or more conditions based on the signal quality (e.g., RSRP or RSRQ) of one or more possible target cells (or candidate cells). (The one or more additional CHO conditions may include one or more conditions defined by radio standards such as 3GPP NR or LTE.) The network may indicate one or more thresholds to be used in conjunction with testing one or more signal quality conditions. For example, it may be required that the RSRP or RSRQ of a reference signal transmitted by a possible target cell is greater than a threshold in order to perform a handover to that cell.

[0160] In some implementations, area information and size parameters may be included in CHO configuration and / or CHO measurement triggering transmitted from the network to the UE via a non-terrestrial platform (NTP). In some implementations, area information may be implemented as GNSS coordinates, and size parameters may be implemented as GPS accuracy.

[0161] In some implementations, new fields may be introduced in the 3GPP 5GNR CHO report configuration and / or 3GPP 5GNR CHO measurement trigger to transmit GNSS coordinates and / or GPS accuracy to the UE.

[0162] In some implementations, GNSS coordinates and / or GPS accuracy may be included. Figure 8 In the reconfiguration message 814 (e.g., in the RRC reconfiguration measurement index of the reconfiguration message).

[0163] In some implementations, the actual format of GNSS coordinates can be similar to the geographic area coordinates (IE) or warning area coordinates (IE) from SIB8 of 3GPP TS38.331. (IE is an acronym for Information Element.) GNSS coordinates can indicate a polygon of the area where a CHO can be applied.

[0164] Upon receiving GNSS coordinates and GPS accuracy, the UE can evaluate location-based CHO conditions as described above. If the location-based conditions are met, one or more additional CHO conditions can be evaluated. If one or more additional CHO conditions are met, the UE can begin the handover process to the target cell.

[0165] In some implementations, before designating a candidate cell as the target cell for conditional handover, the UE may apply location-based conditions to the candidate cell (i.e., the potential target cell). For example, the UE may receive area information for the candidate cell, for instance, from currently serving satellites. This area information may indicate or specify the area of ​​the potential target cell. For example, the area may be the coverage area of ​​the candidate cell or a portion of that coverage area. (Optionally, the UE may also receive a size parameter of the candidate cell, wherein the size parameter determines the radius R of the neighborhood of the area boundary). If the UE determines that its current GPS location is within this area (or alternatively, within the radius R neighborhood of the area boundary), the UE may select the candidate cell as the target cell for handover, or it may test one or more additional CHO conditions to determine whether to perform a conditional handover to the candidate cell.

[0166] In one set of embodiments, the method 1100 for operating the device may include Figure 11 The operation shown. (Method 1100 may also include the above combined with...) Figures 1 to 10B The above and the following text are combined Figures 12 to 15 Any subset of the features, elements, or operations described.) Method 1100 may be executed by processing circuitry, for example by processing element 610 of user equipment 600.

[0167] At 1110, the processing circuitry can receive area information and size parameters from a non-terrestrial network (NTN), such as from an NTN base station. The area information can indicate the region of a serving cell associated with the non-terrestrial platform (NTP) of the NTN. For example, the region can be (or include) the coverage area of ​​the serving cell or a portion of the coverage area of ​​the serving cell. The size parameters can indicate the size of a neighborhood of the region's boundary, for example, as described in the various above. For example, the size parameter can indicate the radius R of the neighborhood, where the neighborhood is defined as the set of points at a distance less than R from the region boundary.

[0168] At 1115, in response to determining that the UE's current location is within the neighborhood, the processing circuit can perform (or initiate) a conditional handover (CHO) of the UE from the serving cell to the target cell of the NTN.

[0169] In some implementations, the base station may be stationary on Earth and transmit area information and size parameters to the UE via an NTP (e.g., an NTP associated with the serving cell). Alternatively, the base station may be located within an NTP. In the context of 3GPP 5GNR, the base station may be a gNB.

[0170] In some implementations, performing a condition switching action may include testing one or more additional CHO conditions, such as those described above.

[0171] In some implementations, the NTP is a satellite or high-altitude platform (HAP) or a spacecraft or lunar-based transceiver station.

[0172] In some implementations, area information and size parameters may be received as part of a reconfiguration message in the Radio Resource Control (RRC) protocol.

[0173] In some implementations, as described above, area information and size parameters can be received as part of the measurement index of the reconfiguration message.

[0174] In some implementations, the processing circuitry may receive additional area information and additional size parameters for the target cell of the NTN, wherein the additional area information indicates an additional area of ​​the target cell, and the additional size parameters indicate the size of an additional neighborhood including the boundary of the additional area. The conditional handover to the target cell may be further conditional on the UE's current location being within the additional neighborhood, for example, as described above.

[0175] In some implementations, the UE may include a GPS receiver, wherein the GPS receiver is configured to determine the current location of the UE in response to a request from the processing circuitry.

[0176] In some implementations, performing conditional handover includes testing conditions regarding the signal quality of the target cell.

[0177] In some implementations, the UE may include: an RF transceiver; and an antenna array coupled to the RF transceiver.

[0178] In one set of embodiments, a method for operating the device may include the following operations. (The method may also include the above-described combinations.) Figures 1 to 11 The above and the following text are combined Figures 12 to 15(Any subset of the features, elements, or operations described herein.) This method may be executed by processing circuitry, for example, by processing element 610 of user equipment 600. The processing circuitry may receive area information from a non-terrestrial network (NTN), such as from an NTN base station. The area information may indicate a sub-area of ​​the coverage area of ​​a serving cell associated with a non-terrestrial platform (NTP) of the NTN. In response to determining that the UE's current location is within a sub-area, the processing circuitry may perform (or initiate) a conditional handover (CHO) of the UE from the serving cell to a target cell of the NTN. The network may assign different sub-areas to different UEs (or different subsets of UEs) served by the serving cell to distribute the load of CHO processing.

[0179] In one set of embodiments, a method for operating the device may include the following operations. (The method may also include the above-described combinations.) Figures 1 to 11 The above and the following text are combined Figures 12 to 15 (Any subset of the features, elements, or operations described herein.) This method may be performed by processing circuitry, for example by processing element 610 of user equipment 600. The processing circuitry may receive area information from a non-terrestrial network (NTN), such as from an NTN base station. This area information may indicate a sub-area of ​​the coverage area of ​​a possible target cell associated with the non-terrestrial platform (NTP) of the NTN. In response to determining that the UE's current location is within a sub-area, the processing circuitry may perform (or initiate) a conditional handover (CHO) of the UE from the serving cell to a possible target cell of the NTN. The network may assign different sub-areas to different UEs (or different subsets of UEs) served by the serving cell to distribute the load of CHO processing.

[0180] In some implementations, a method for operating a serving base station may include operations to facilitate a conditional handover of a user equipment (UE) from the serving cell of the serving base station. (The method may also include the above-described combinations...) Figures 1 to 11 The above and the following text are combined Figures 12 to 15 (Any subset of the features, elements, or operations described above.) This method can be executed by processing circuitry, such as by processing element 710 of base station 700. In response to receiving a conditional handover confirmation, for example, as described above... Figure 8 The processing circuitry can transmit a reconfiguration message, including area information and size parameters, to the user equipment (UE) served by the serving cell. The area information can indicate an area corresponding to a non-terrestrial platform (NTP) of a non-terrestrial network (NTN), such as the NTP used by the serving base station to mediate the serving cell. For example, the area can correspond to the coverage area of ​​the NTP or a portion of its coverage area. The size parameters can indicate the size (or radius) of the neighborhood of the area boundary.

[0181] Furthermore, in response to receiving a reconfiguration complete message from the UE, the processing circuitry can transmit an early state transmission message to the target base station for conditional handover and begin forwarding user data to the target base station. In response to an indication from the UE that conditional handover to the target base station is complete, the processing circuitry can transmit a handover success message to the target base station.

[0182] In some implementations, the processing circuitry can be configured with different UEs (or different subsets of UEs) in different areas with the coverage area of ​​the serving cell to distribute the load of CHO processing.

[0183] Power consumption based on location switching

[0184] Because location-based conditional handover processes may require repeated (e.g., frequent) transmissions of cell coverage information and size parameters from the network, as well as repeated testing of location-based CHO conditions until they are met, location-based CHO processes can consume power at what is considered an excessive rate in some cases. Therefore, this disclosure explores other possible solutions for conditional handover in NTN networks.

[0185] Timer-based conditional switching

[0186] In some implementations, the UE can perform a timer-based Conditional Handover (CHO). The network (e.g., a base station of the network) can transmit a timer value to the UE via a non-terrestrial platform (NTP). (For example, the NTP corresponding to the current serving cell can transmit or forward the timer value to the UE.) The timer value can indicate the amount of time the UE should wait before testing one or more additional CHO conditions. (The timer value can be indicated from a standardized list or configuration list of possible values.) The timer value can, for example, represent the amount of time the UE is guaranteed to be within the coverage area of ​​the current serving cell.

[0187] In response to receiving a timer value, the UE can start a timer (e.g., a counter device) based on the timer value. When the timer expires (i.e., when the timer has completed counting the indicated amount of time), the UE can test one or more additional CHO conditions. As described above, the one or more additional CHO conditions may include one or more conditions based on signal quality such as RSRP or RSRQ. In response to determining that one or more additional CHO conditions are met, the UE can perform a handover to a target cell (e.g., a cell associated with a different satellite).

[0188] In some implementations, timer configuration (e.g., timer values) may be provided by the network based on ephemeris data, such as ephemeris data used to mediate or host satellites of the currently serving cell.

[0189] In some implementations, the timer value has a value on the order of seconds. However, in varying environments and network deployments, a wide range of values ​​is possible.

[0190] In some implementation schemes, Figure 8 The reconfiguration message 814 (e.g., in the reconfiguration measurement index of the reconfiguration message) may include a timer value. For example, the reconfiguration measurement index may include a timer field (referred to herein as "UponTimerExpiry") carrying the timer value.

[0191] In some implementations, the network may provide ephemeris data to the UE, such as ephemeris data for mediating or hosting satellites of the currently serving cell. The UE may frequently apply CHO configurations to check whether one or more CHO criteria defined by the CHO configuration are met.

[0192] In some implementations, the timer can count clock ticks or absolute time.

[0193] In some implementations, the network may transmit a timer value corresponding to a possible target cell (e.g., via a currently serving satellite to the UE). The timer value may represent the amount of time the UE should wait before considering the possibility of a conditional handover to the possible target cell. In some cases, the network is able to predict the amount of time before the UE enters the coverage area of ​​the possible target cell and provide an appropriate timer value accordingly. Furthermore, the network may assign different timer values ​​to different UEs to distribute the handover load across possible target cells. In response to receiving a timer value, the UE may start a timer based on the timer value. When the timer expires (i.e., the count of the amount of time defined by the timer value is complete), the UE may test one or more additional CHO conditions. One or more additional CHO conditions may include, for example, signal quality conditions regarding the RF signal of the possible target cell. For example, it may be required that the signal quality of a reference signal of the possible target cell is greater than a threshold configured by the network in order to enable a handover to the possible target cell.

[0194] Timer-based CHO with time range

[0195] In some implementations, the UE can use a time range provided by the network to perform time-based conditional handover (CHO). The network (e.g., a base station of the network) can transmit time range information to the UE via an off-land platform (NTP) (e.g., an off-land platform hosting or mediating the currently serving cell). The time range information can indicate time values ​​t1 and t2 that define the time range [t1, t2] within which the off-land platform is visible to the UE, or within which the UE can perform (or initiate) a conditional handover. The network can provide different time ranges to different subsets of the UE to temporally extend the load of conditional handover processing for the UE within the cell.

[0196] In response to receiving time range information, the UE can select (e.g., randomly select) a value T within the time range [t1, t2] and start a timer based on the selected value T. In response to the timer expiring, the UE can test one or more additional CHO conditions. As described above, the one or more additional CHO conditions may include one or more conditions based on signal quality such as RSRP or RSRQ. In response to determining that one or more additional CHO conditions are met, the UE can perform a handover to a target cell (e.g., a cell associated with a different NTP).

[0197] In some implementations, the network can transmit a random seed along with time range information to the UE. The UE can use the random seed to randomize its choice of value T within the time range [t1, t2]. Randomization of the value T selection is used to temporally extend the processing load of conditional handover for UEs receiving the same time range [t1, t2]. Besides using a random seed, the UE can also employ one or more randomization techniques to select the value T. Therefore, even if different UEs receive the same time range [t1, t2] and the same random seed, they can still choose different values ​​for time T.

[0198] In some implementation schemes, Figure 8 The reconfiguration message 814 (e.g., in the reconfiguration measurement index of the reconfiguration message) may include time range information and / or a random seed.

[0199] In some implementations, the network may transmit time range information for possible target cells. This time range information indicates a time range [t1, t2] corresponding to a possible target cell. The network may assign different time ranges to different subsets of UEs to distribute the handover load across possible target cells. In response to receiving the time range information, the UE may select (e.g., randomly select) a time value T within the time range [t1, t2] and start a timer with time value T. When the timer expires, the UE may consider the likelihood of handover to a possible target cell, for example, by testing one or more (network-configured) additional CHO conditions. The one or more additional CHO conditions may include conditions regarding the RF signal quality of the possible target cell. For example, the UE may determine whether the RF signal quality (e.g., RSRP or RSRQ) of a reference signal transmitted by the possible target cell is greater than a threshold. If one or more additional CHO conditions are met, the UE may designate the possible target cell as the target cell for handover and perform a handover to the target cell. Furthermore, the network may provide a random seed along with the timer range information to allow the UE to randomize its selection of time value T.

[0200] RNTI-based randomization of time value selection

[0201] As described above, the network can provide time range information (including time values ​​t1 and t2) and a random seed. In some implementations, as an alternative to providing a random seed, the network can provide the UE with a UE-specific random value. The network can determine the UE-specific random value by selecting (e.g., randomly selecting) a value V0 and calculating the UE-specific random value V based on this relationship. UE .

[0202] V UE =V0 mod CRNTI UE ,

[0203] Where "mod" represents the modulo operation, and CRNTI UE The CRNTI is a unique temporary identifier assigned to a UE by the cell radio network. The network or base station can assign different CRNTI values ​​to different UEs within the cell. Base stations can use CRNTIs to assign uplink grants, downlink allocations, etc., to UEs. Furthermore, base stations can use CRNTIs to distinguish uplink transmissions from different UEs, such as PUSCH and PUCCH.

[0204] In response to receiving time range information and a UE-specific random value V UE The UE can use the value V UEA time value T within the range [t1, t2] is deterministically selected. The UE can then start a timer based on the time value T, as described above.

[0205] In some implementation schemes, the base station can Figure 8 In the reconfiguration message 814 (e.g., in the reconfiguration measurement index of the reconfiguration message), a UE-specific random value V is transmitted to the UE. UE-- And time range information.

[0206] Alternatively, the network may transmit the selected value V0 to the UE (instead of a UE-specific random value V). UE Furthermore, the UE can use this relationship to calculate a UE-specific random value V. UE .

[0207] V UE =V0 mod CRNTI UE .

[0208] When a UE transitions from idle mode to connected mode, the network can assign the value CRNTI to the UE. UE .

[0209] In some implementations, the network can combine time range information indicating the possible target cell's time range [t1,t2] with a UE-specific random value V. UE Transmit together (to the UE). The UE can use a timer to apply a waiting time T selected from the time range [t1, t2] as described above. The UE can use a UE-specific random value V. UE The choice of a randomized waiting time T is determined. During the waiting time, the UE does not consider handover to a possible target cell. When the timer expires (after the waiting time T has been calculated), the UE can test one or more additional CHO conditions. The one or more additional CHO conditions may include conditions regarding the RF signal quality of the possible target cell. If one or more additional CHO conditions are met, the UE can perform (or initiate) a handover to the possible target cell.

[0210] Figure 12 -Time-based condition switching

[0211] In one set of embodiments, the method 1200 for operating the device may include Figure 12 The operation shown. Method 1200 may also include the above-described combination. Figures 1 to 11 The above and the following, in conjunction with Figures 13 to 14, are described. Figure 15 Any subset of the features, elements, or operations described. Method 1200 can be executed by processing circuitry, such as by processing element 610 of user equipment 600.

[0212] At 1210, the processing circuitry can receive time information from a non-terrestrial network (NTN), such as from an NTN base station. This time information is associated with the serving cell of the NTN. The serving cell can be mediated by a non-terrestrial platform (NTP), such as a satellite, high-altitude platform (HAP), or UAV or aircraft.

[0213] At 1210, in response to receiving time information, the processing circuitry can start a timer with a time value determined using the time information. This timer can count the ticks of a clock residing in the UE. In one embodiment, the timer may include a counter device that decrements in response to clock ticks, and a comparator that determines when the value of the counter device reaches zero. However, it should be understood that various ways exist to implement a timer in the circuitry.

[0214] At 1210, in response to the expiration of the timer, the processing circuit can perform a conditional handover (CHO) of the UE from the serving cell to the target cell of the NTN, for example, as described above.

[0215] In some implementations, the base station may be stationary on Earth and transmit time information to the UE via an NTP (e.g., an NTP associated with the serving cell). Alternatively, the base station may be located within an NTP. In the context of 3GPP 5GNR, the base station may be a gNB.

[0216] In some implementations, the time information may include an indication of a time value. For example, the time information may indicate a time value from a standardized list of possible values ​​or a list of network configurations of possible values.

[0217] In some implementations, the time information may include an indication of a random seed and a time range. The time value of action 1210 may be randomly selected from a timer range based on the random seed, for example, as described above.

[0218] In some implementations, the time information may include: a UE-specific random value; and an indication of a time range, wherein the time value is selected from the time range using the UE-specific random value.

[0219] In some implementations, the serving cell can be mediated by NTN’s satellites or High Altitude Platform (HAP).

[0220] In some implementations, time information is received as part of a reconfiguration message for the Radio Resource Control (RRC) protocol, for example, as described in the various above.

[0221] In some implementations, performing a condition switching action may include determining the validity of one or more additional CHO conditions, for example, as described in the various above.

[0222] In some implementations, performing conditional handover may include verifying the validity of conditions regarding the signal quality of the target cell.

[0223] In some implementations, a method for operating a serving base station may include operations to facilitate a conditional handover of a user equipment (UE) from the serving cell of the serving base station. The method may also include the above-described combinations. Figures 1 to 12 The above and the following, in conjunction with Figures 13 to 14, are described. Figure 15 Any subset of the described features, elements, or operations. The method can be executed by processing circuitry, such as processing element 710 of base station 700. In response to receiving a conditional handover confirmation, for example, as described above... Figure 8 The processing circuitry can transmit a reconfiguration message, including time information, to a user equipment (UE) served by the serving cell. The time information can instruct the UE to apply a waiting time before initiating a conditional handover from the serving base station (or serving cell).

[0224] In response to receiving a reconfiguration complete message from the UE, the processing circuitry can transmit an early state transmission message to the target base station for conditional handover and begin forwarding user data to the target base station. In response to an indication from the UE that conditional handover to the target base station is complete, a handover success message is transmitted to the target base station.

[0225] In some implementations, the time information includes an indication of the waiting time. The serving base station can allocate different waiting times to different UEs (or different subsets of UEs) to distribute the load of CHO processing.

[0226] In some implementations, the time information includes an indication of a random seed and a time range, whereby the UE can randomly select a waiting time from the timer range based on the random seed. The serving base station can allocate different time ranges to different UEs (or different subsets of UEs) to distribute the load of CHO processing.

[0227] In some implementations, the time information includes: a UE-specific random value; and an indication of a time range, from which a time value can be selected (by the UE) based on the UE-specific random value. The serving base station can allocate different time ranges to different UEs (or different subsets of UEs) to distribute the load of CHO processing.

[0228] Conditional switching based on elevation angle

[0229] In some implementations, the UE can perform conditional handover (CHO) based on the elevation angle of a satellite (e.g., the satellite corresponding to the currently serving cell). The network (e.g., a base station of the network) can transmit satellite ephemeris data to the UE, for example, via the satellite. Each satellite can periodically broadcast ephemeris data that the UE can use to determine the satellite's position within a time window. The ephemeris data may include one or more of the following: orbital parameters, clock correction factor, data age, satellite accuracy, and week number. The UE can use the ephemeris data to calculate the satellite's current position relative to the Earth and use a GPS receiver to determine the UE's GPS position. The UE can then determine (using triangulation) the satellite elevation angle at the current time based on the calculated satellite position and the UE's GPS position. (The satellite is an example of a non-terrestrial platform.) Figure 13B The elevation angle θ of a non-land platform (NTP) relative to the horizon is shown according to some embodiments. NTP (Definition.) This calculation of satellite elevation angle takes into account the characteristics of the Earth's surface. UE can calculate the satellite's elevation angle θ. S With the threshold θ provided by the network CHO Compare them. If the satellite's elevation angle θ S Less than threshold θ CHO The UE can then test one or more additional CHO conditions, such as those described above. For example, one or more additional CHO conditions may include one or more conditions related to signal quality. If one or more additional CHO conditions are met, the UE can perform a handover to a target cell, i.e., a cell mediated or managed by a different satellite.

[0230] In some implementations, the base station may, for example, indicate an elevation angle threshold θ to the UE in a configuration message. CHO For example, it can be done Figure 8 The threshold θ is provided to the UE in the reconfiguration message 814 (e.g., in the reconfiguration measurement index of the reconfiguration message). CHO The base station can transmit an indicator of the elevation angle threshold from a standardized list of thresholds (or a network configuration list).

[0231] In some implementations, the base station can also provide the UE with an elevation angle threshold θ. TH This elevation angle threshold will be applied to the satellite S corresponding to the possible target cell (PTC). PTC The UE can be accessed from satellite S. PTC (or receive satellite S from the network via the current serving cell) PTC Ephemeris data; calculation of satellite S based on ephemeris data PTC The location; and the calculation of satellite S based on satellite location and the UE's current GPS location. PTC The angle of elevation θ sPTCThen, the UE can send satellite S PTC The angle of elevation θ sPTC With elevation angle threshold θ TH Comparison. UE can request the elevation angle θ. sPTC greater than the elevation angle threshold θ TH This allows for a switch to a potential target cell. In some cases, the elevation angle of the satellite corresponding to the potential target cell can be defined as a negative angle, while the elevation angle of the currently serving satellite can be defined as a positive angle. In these cases, the elevation angle threshold θ... TH Both are negative values, and the UE can request the elevation angle θ. sPTC Less than the elevation angle threshold θ TH This enables the handover to a potential target cell.

[0232] In some implementations, if satellite S PTC The angle of elevation θ sPTC Less than (or alternatively, depending on the elevation angle θ) sPTC The sign convention is greater than the elevation angle threshold θ. TH And the service satellite's elevation angle θ S Less than threshold θ CHO Then the UE can test one or more additional CHO conditions, such as those described above. One or more additional CHO conditions may include conditions regarding the RF signal quality of a possible serving cell.

[0233] In one set of embodiments, the method 1300 for operating the device may include Figure 13A The operation shown. Method 1300 may also include the above-described combination. Figures 1 to 12 The above, and the following in conjunction with Figure 14 and Figure 15 Any subset of the features, elements, or operations described. Method 1300 may be executed by processing circuitry, for example by processing element 610 of user equipment 600.

[0234] At 1310, the processing circuit can receive information indicating the elevation angle threshold of the non-terrestrial platform (NTP) associated with the currently serving cell of the non-terrestrial network (NTN). The elevation angle threshold can be received from the base station of the NTN via the NTP.

[0235] At position 1315, the processing circuit can determine the elevation angle θ of the NTP. NTP .like Figure 13B As shown, the elevation angle θ NTP It can be defined relative to a horizontal line (or horizontal ray), for example, residing on the zenith ray of the UE and the vector V connecting the UE position and the NTP position. UE,NTP The horizontal line in the defined plane.

[0236] Back Figure 13AAt 1320, in response to determining the elevation angle θ NTP If the elevation angle is less than the threshold, the processing circuit can perform conditional handover to the target cell of the NTN.

[0237] In some implementations, the base station may be stationary on Earth and transmit elevation thresholds to the UE via an NTP (e.g., an NTP associated with the current serving cell). Alternatively, the base station may be located within an NTP. In the context of 3GPP 5GNR, the base station may be a gNB.

[0238] In some implementations, determining the elevation angle of the NTP may include determining the NTP's position based on NTP ephemeris data; and determining the NTP's elevation angle based on the NTP's position and the UE's current position. The device may include a GPS receiver to support the determination of the UE's current position.

[0239] In some implementations, the processing circuitry can receive broadcasts of ephemeris data from the NTP before determining the elevation angle of the NTP.

[0240] In some implementations, the processing circuitry may receive additional information indicating an additional elevation angle threshold for another NTP associated with the target cell. Furthermore, the action of performing a conditional handover to the target cell may include verifying that the elevation angle of the other NTP satisfies an inequality condition relative to the additional elevation angle threshold. As mentioned above, the meaning of the inequality (greater than or less than) may depend on the notation convention used for the elevation angle.

[0241] In some implementations, the information of action 1310 may be received as part of a reconfiguration message of the Radio Resource Control (RRC) protocol, for example, as described in the various above.

[0242] In some implementations, performing condition handover may include verifying the validity of conditions regarding the signal quality of the target cell, for example, as described in the various above.

[0243] In some implementations, the NTP is a satellite or high-altitude platform (HAP).

[0244] In an alternative implementation, the UE may receive information indicating the elevation angle range of a non-terrestrial platform corresponding to the serving cell (or a possible target cell). The UE may calculate the elevation angle of the serving cell (or a possible target cell) and determine whether the calculated elevation angle is within the elevation angle range. If so, the UE may perform (or initiate) a conditional handover from the serving cell (or, to, the possible target cell), for example, as described in the various above. The base station may assign different elevation angle ranges to different UEs (or different subsets of UEs) within the serving cell.

[0245] In some implementations, a method for operating a serving base station may include operations to facilitate a conditional handover of a user equipment (UE) from the serving cell of the serving base station. The method may also include the above-described combinations. Figures 1 to 1 The above-described and the following description, in conjunction with Figures 14 to 15, further illustrate this point. Figure 15 Any subset of the described features, elements, or operations. The method can be executed by processing circuitry, such as processing element 710 of base station 700. In response to receiving a conditional handover confirmation, for example, as described above... Figure 8 The processing circuitry can transmit a reconfiguration message that indicates or specifies the elevation angle threshold of the non-terrestrial platform (NTP) of the NTN, for example, to mediate the NTP of the serving cell for the serving base station.

[0246] In response to receiving a reconfiguration complete message from the UE, the processing circuitry can transmit an early state transmission message to the target base station for conditional handover and begin forwarding user data to the target base station. In response to an indication from the UE that the conditional handover to the target base station is complete, the processing circuitry can transmit a handover success message to the target base station.

[0247] In some implementations, the processing circuitry is further configured to broadcast ephemeris data for one or more NTPs, including the NTP of the serving cell.

[0248] In some implementations, the processing circuitry can assign different elevation angle thresholds to different UEs (or different subsets of UEs) to distribute the load of CHO processing.

[0249] Combination of conditional switching standards

[0250] In some implementations, a combination of two or more of the aforementioned CHO standards may be used to provide more robust conditional handover between satellite-based cells in a non-terrestrial network (NTN). For example, in one implementation, the UE may use a location-based standard and a timer-based standard (with network indication time or network indication time range). In another implementation, the UE may use a timer-based standard (with network indication time or network indication time range) and an elevation-based standard. In yet another implementation, the UE may use a location-based standard and an elevation-based standard. In yet another implementation, the UE may use a location-based standard, a timer-based standard (with network indication time or network indication time range), and an elevation-based standard.

[0251] In one set of embodiments, the method 1400 for operating the device may include Figure 14A The operation shown. Method 1400 may also include the above-described combination. Figures 1 to 1 The above and the following text are combined Figures 14B to 16Any subset of the features, elements, or operations described. Method 1400 may be executed by processing circuitry, for example by processing element 610 of user equipment 600.

[0252] At 1410, the processing circuitry can receive configuration messages from a non-terrestrial network (NTN), such as from a non-terrestrial platform of the NTN. The configuration messages can indicate one or more Conditional Handover (CHO) criteria applied by the UE during conditional handover. Each of the one or more CHO criteria can be based on corresponding information other than signal quality, such as those described above. Figure 8 The configuration message is implemented through the reconfiguration message 814 or by reconfiguring the measurement index through the reconfiguration message 814.

[0253] At 1420, in response to determining that one or more CHO criteria are met, the processing circuitry may optionally perform a conditional handover (CHO) of the UE from the serving cell to the target cell of the NTN. The execution of the conditional handover may include testing one or more additional CHO conditions, such as one or more CHO conditions based on the signal quality of the possible target cell.

[0254] In some implementations, one or more CHO standards may include multiple CHO standards, wherein the multiple CHO standards have different types. For example, the multiple CHO standards may include two or more of the following: a location-based CHO standard; a timer-based CHO standard with an indicated time value; a timer-based CHO standard with an indicated time range; and an elevation-based CHO standard.

[0255] In one set of embodiments, method 1450 for operating a device in the context of a non-terrestrial network (NTN) may include Figure 14B The operation shown. Method 1450 may also include the above-described combination. Figures 1 to 14A The above and the following text are combined Figure 15 and Figure 16 Any subset of the features, elements, or operations described. Method 1450 may be executed by processing circuitry, for example by processing element 710 of user equipment 700.

[0256] At 1455, the processing circuitry can transmit a reconfiguration message to the User Equipment (UE), wherein the reconfiguration message indicates one or more Conditional Handover (CHO) criteria for conditional handover of the UE from the NTN's current serving cell. The reconfiguration message can be transmitted, for example, via... Figure 8 This is achieved through reconfiguration message 814 (or the reconfiguration measurement index of reconfiguration message 814), for example, as described above. Each of the one or more conditional switching criteria can be based on corresponding information other than signal quality.

[0257] In some implementations, one or more CHO standards may include multiple CHO standards, and the CHO standards among the multiple CHO standards may be of different types. For example, the multiple CHO standards may include two or more of the following: a location-based CHO standard; a timer-based CHO standard with an indicated time value; a timer-based CHO standard with an indicated time range; and an elevation-based CHO standard.

[0258] In response to receiving a reconfiguration complete message from the UE, the processing circuit can transmit an early state transmission message to the target base station of the condition switching and begin forwarding user data to the target base station.

[0259] In some implementations, transmission operation 1455 can be performed in response to receiving a conditional handover confirmation message from each of one or more possible target cells of the UE, for example, in combination with the above. Figure 8 As stated above.

[0260] Prioritization among multiple NTN cells

[0261] In some implementations, multiple NTN cells can exist that can be configured for the UE. For example, the UE can be configured for both low Earth orbit (LEO) and geostationary orbit (GEO) satellites. As another example, the UE can be configured for both high altitude platform (HAP) and LEO satellites. As yet another example, the UE can be configured for both HAP and GEO satellites. As yet another example, the UE can be configured for both medium Earth orbit (MEO) satellites, LEO satellites, and HAP. As yet another example, the UE can be configured for a first LEO satellite (LEO1), a second LEO satellite (LEO2), and a GEO satellite, for example, such as... Figure 15 As shown. A cell mediated by LEO1 can have an occupied area FP1; a cell mediated by LEO2 can have an occupied area FP2; and a cell mediated by GEO can have an occupied area FP... GEO The UE can reside in the occupied areas FP1, FP2, and FP3. GEO Two or more of the occupied areas.

[0262] When a UE is configured for multiple non-terrestrial platforms (NTPs), it is desirable to avoid conditional handovers between NTP-based cells in response to random (or short-term) changes in cell RF signal strength, especially when the target cell is already overloaded with the client UE. For example, it might be desirable to avoid unnecessary handovers to GEO satellites, which can cover large geographic areas and therefore bear a large number of client UEs. (NTPs can include platforms such as GEO, MEO, LEO, HAP, etc., or any combination thereof.)

[0263] In some implementations, each potential target cell configured for the UE is assigned (a) a corresponding priority level and (b) a corresponding initial CHO criterion for conditional handover to the potential target cell. The network transmits the priority level and the initial CHO defining each potential target cell to the UE, for example, via the current serving cell. For example, as shown in the table below, this table... Figure 15 Relatedly, a GEO satellite cell can be configured with priority level 3 and a location-based standard using GNSS coordinates and GPS accuracy; a first LEO satellite (LEO1) cell can use a time range [t1,t2] and a first random seed, configured with priority level 1 and a timer-based standard; and a second LEO satellite (LEO2) cell can use a time range [t3,t4] and a second random seed, configured with priority level 2 and a timer-based standard.

[0264] Table: Prioritization Scheme

[0265]

[0266] At any given time, the UE can determine that initial CHO criteria are met for two or more possible target cells. In this case, the UE can select the cell with the highest priority (from the two or more possible target cells). The UE can then test one or more additional CHO criteria for conditional handover to the selected cell. The one or more additional CHO criteria may include criteria based on the RF signal quality of the selected cell. If one or more additional CHO criteria are met, the UE can perform a handover to the selected cell. In at least some implementations, the network may need to provide continuous copies of user data to all possible target gNBs because there is uncertainty about which target gNB the UE will move to. While redundancy exists in copying user data to multiple possible targets, this process ensures that latency is minimized.

[0267] In some implementations, the network can transmit configuration information (to the UE) CThis configuration information indicates (a) the corresponding priority level and (b) the corresponding CHO parameters for each configured cell of the UE. A corresponding CHO standard can be selected from the above CHO standards. For example, a corresponding CHO standard can be selected from the following list (or from a sublist of the following list):

[0268] Location-based CHO standards with coverage area and size parameters for network configuration;

[0269] A timer-based CHO standard with network configuration time values;

[0270] A timer-based CHO standard with network configuration time range and random seed;

[0271] A timer-based CHO standard with network configuration time range and RNTI-based randomization;

[0272] An elevation-based CHO standard with network configuration elevation angle thresholds (or standard-defined thresholds).

[0273] In some implementation schemes, Figure 8 The reconfiguration message 814 (or the reconfiguration measurement index of reconfiguration message 814) may include the aforementioned priority configuration information I. PC .

[0274] In some implementations, the prioritization scheme described above allows for the selection of a target cell, for example, when individual RF conditions cannot produce a definite winner among the configured candidates. This prioritization scheme may be referred to herein as Modified Conditional Handover (m-CHO).

[0275] In some implementations, the network may determine the priority of configured cells based on one or more factors, such as: reports received from the UE, for example, reports of signal quality received by the UE from each cell in the cell; measurements of traffic load in each cell in the cell; the frequency of the cell; and so on.

[0276] In one set of embodiments, the method 1600 for operating the device may include Figure 16 The operations shown in the figure. Method 1600 may also include the above in combination. Figures 1 to 15 Any subset of the features, elements, and operations described. Method 1600 may be executed by processing circuitry, for example by processing element 610 of user equipment 600.

[0277] At 1610, the processing circuit can receive configuration information. For each of the multiple possible target cells in the non-terrestrial network (NTN), the configuration information can indicate: (a) the corresponding priority level and (b) the corresponding indication information defining the corresponding conditional handover (CHO) standard.

[0278] In some implementations, each of the possible target cells has a different priority than the other possible target cells. In other words, different possible target cells are assigned different priority levels. In other implementations, some (but not all) of the possible target cells may share the same priority level, and mechanisms based on one or more criteria other than priority level can be used to break ties between possible target cells with the same priority level.

[0279] At 1615, in response to determining that the CHO criteria of two or more possible target cells are met, the processing circuit can select the cell with the highest priority level from the two or more possible target cells.

[0280] At 1620, the processing circuitry can perform conditional handover to the selected cell, for example, as described above.

[0281] In some implementations, the configuration information described above may be received as part of a reconfiguration message in the Radio Resource Control (RRC) protocol, for example, as described above. Figure 8 The description is part of reconfiguration message 814 or reconfiguration measurement index.

[0282] In some implementation schemes, for each possible target cell among the possible target cells, the corresponding CHO standard belongs to a set of standards including: location-based CHO standard; timer-based CHO standard; and elevation angle-based CHO standard.

[0283] In some implementations, for each possible target cell among the possible target cells, the corresponding CHO standard belongs to a set of standards including: location-based CHO standards with coverage area and size parameters of network configuration; timer-based CHO standards with network configuration time values; timer-based CHO standards with network configuration time range and random seed; timer-based CHO standards with network configuration time range and RNTI-based randomization; elevation-based CHO standards with network configuration elevation angle threshold (or standard-defined threshold); or combinations thereof.

[0284] In some implementations, the first possible target cell in the possible target cells corresponds to a geostationary satellite, and the second possible target cell in the possible target cells corresponds to a non-terrestrial platform of a non-geostationary satellite.

[0285] In some implementations, the action of performing a conditional handover to a target cell may include verifying the validity of conditions regarding the signal quality of the target cell before handover, for example, as described above.

[0286] In some implementations, the number of possible target cells among the plurality of possible target cells is greater than or equal to 3, for example, as suggested in the table above.

[0287] In some implementations, the device may also include a GPS receiver configured to determine the current location of the UE in response to a request from the processing circuitry.

[0288] In some implementations, a method for operating a serving base station may include operations to facilitate a conditional handover of a user equipment (UE) from the serving cell of the serving base station. The method may also include the above-described combinations. Figures 1 to 16 Any subset of the features, elements, and operations described herein. This method can be executed by processing circuitry, such as processing element 710 of base station 700. The processing circuitry can transmit a reconfiguration message to user equipment (UE). For each of multiple possible target cells (conditionally switched) in a non-terrestrial network (NTN), the reconfiguration message can indicate (a) the corresponding priority level and (b) the corresponding CHO information defining the corresponding conditional switching (CHO) standard.

[0289] In some implementations, in response to receiving a reconfiguration complete message from the UE, the processing circuitry may transmit an early state delivery message to the target base station for conditional handover and begin forwarding user data to the target base station. In response to an indication from the UE that the conditional handover to the target base station is complete, the processing circuitry may transmit a handover success message to the target base station.

[0290] In some implementations, the action of transmitting a reconfiguration message can be performed in response to receiving a conditional handover acknowledgment from each of one or more possible target cells of the UE, for example, in combination with the above. Figure 8 As stated above.

[0291] In some implementations, the base station may be included as part of a non-terrestrial platform (NTP). The NTP can mediate one or more cells of the NTN. For example, the NTP can mediate the serving cell of the UE.

[0292] In some implementations, the base station may be configured to wirelessly communicate with the non-terrestrial platform of the serving cell of the mediating UE.

[0293] In some implementations, the non-transitory memory medium may store program instructions. When executed by processing circuitry, the program instructions may cause the processing circuitry to perform any of the above-described method implementations and any combination thereof. The memory medium may be incorporated as part of a base station.

[0294] Embodiments of this disclosure may be implemented in any of a variety of forms. For example, some embodiments may be implemented as computer-implemented methods, computer-readable storage media, or computer systems. Other embodiments may be implemented using one or more custom-designed hardware devices such as ASICs. Other embodiments may be implemented using one or more programmable hardware elements such as FPGAs.

[0295] In some embodiments, a non-transitory computer-readable storage medium may be configured to store program instructions and / or data, wherein if the program instructions are executed by a computer system, the computer system performs a method, such as any method embodiment of the method embodiments described herein, or any combination of the method embodiments described herein, or any subset or combination of any such subset of any method embodiments described herein.

[0296] In some implementations, a computer system may be configured to include a processor (or a group of processors) and a memory medium, wherein the memory medium stores program instructions, and the processor is configured to read from the memory medium and execute the program instructions, wherein the executable program instructions are to implement any of the various method implementations described herein (or any combination of the method implementations described herein, or any subset of any method implementations described herein, or any combination of such subsets). A computer system may be implemented in any of a variety of forms. For example, a computer system may be a personal computer (in any of its various implementations), a workstation, a computer on a card, a dedicated computer in a box, a server computer, a client computer, a handheld device, a user equipment (UE) device, a tablet computer, a wearable computer, etc.

[0297] By interpreting each message / signal X received by a user equipment (UE) communicating with a base station (or transmission-receive point) in the downlink as a message / signal X transmitted by the base station (or transmission-receive point), and interpreting each message / signal Y transmitted by the UE in the uplink as a message / signal Y received by the base station (or transmission-receive point), any method described herein for operating a UE can serve as the basis for a corresponding method for operating a base station (or transmission-receive point).

[0298] As is widely recognized, the use of personally identifiable information should comply with privacy policies and practices that are generally accepted to meet or exceed industry or governmental requirements for protecting user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of authorized use should be clearly explained to users.

[0299] Although the above embodiments have been described in considerable detail, many variations and modifications will become apparent to those skilled in the art once the disclosure is fully understood. This disclosure is intended to render the following claims as encompassing all such variations and modifications.

Claims

1. A method for conditional handover CHO of a user equipment (UE), the method comprising: Receive area information and size parameters for the serving cell and the target cell associated with the NTN from a serving cell associated with the non-terrestrial network NTN, wherein the area information indicates the area of ​​the serving cell and the area of ​​the target cell associated with the non-terrestrial platform NTP of the NTN, wherein the size parameters indicate the size of the neighborhood of the boundary of the area of ​​the serving cell and the size of the additional neighborhood of the boundary of the area of ​​the target cell, wherein the neighborhood and the additional neighborhood include the internal and external areas of the respective areas, and wherein the area information and the size parameters are included in configuration information; as well as In response to determining that the current location of the UE is within the neighboring area and the additional neighboring area, a conditional handover CHO is performed for the UE from the serving cell to the target cell of the NTN.

2. The method according to claim 1, wherein the NTP is a satellite or a high-altitude platform (HAP).

3. The method of claim 1, wherein the area information and the size parameter are received as part of a reconfiguration message of the Radio Resource Control (RRC) protocol.

4. The method of claim 3, wherein the area information and the size parameter are received as part of the measurement index of the reconfiguration message.

5. The method of claim 1, wherein the execution of the conditional handover includes testing the signal quality of the target cell.

6. The method according to claim 1, wherein the area of ​​the serving cell corresponds to the coverage area of ​​the serving cell.

7. The method of claim 1, wherein the configuration information further includes time information, and wherein the time information includes an indication of a random seed and a time range.

8. The method of claim 7, wherein a time value is randomly selected from the time range based on the random seed.

9. The method according to claim 7, wherein the time information includes: UE-specific random values.

10. The method of claim 9, wherein a time value is selected from the time range based on a random value specific to the UE.

11. An apparatus comprising processing circuitry, wherein the processing circuitry is configured to cause a user equipment (UE) to perform the method according to any one of claims 1 to 10.

12. The apparatus of claim 11, wherein the UE includes a GPS receiver, wherein the GPS receiver is configured to determine the current location of the UE in response to a request from the processing circuitry.

13. A non-transitory computer-readable storage medium storing program instructions executable by a baseband processor of a user equipment (UE) to perform the method according to any one of claims 1 to 10.

Images