Method, terminal device and network device for non-terrestrial network satellite handover

Abstract

The application provides a method, a terminal device and a network device for non-terrestrial network satellite switching, which helps to improve the access success rate of RACH-free switching in an NTN cell. The method is applied to satellite switching from a first satellite network coverage area to a second satellite network coverage area, and includes: receiving a first switching command, wherein the first switching command includes power-related information in the second satellite network coverage area and / or relative position information between a second satellite corresponding to the second satellite network and the terminal device; and determining a first power for uplink transmission to the second satellite network according to the first switching command.

Description

Technical Field

[0001] This application relates to the field of communication technology, and more specifically, to a method, terminal equipment, and network equipment for satellite handover in non-terrestrial networks. Background Technology

[0002] To improve user experience and reduce the latency of terminal devices switching from the source cell to the target cell, random access channel-less (RACH-less) handover has been introduced.

[0003] However, in some communication systems (e.g., non-terrestrial network (NTN) systems), the transmission distance between terminal equipment and network equipment is relatively large. In these communication systems, how the terminal equipment determines the uplink transmit power to improve the handover success rate during RACH-less handover is a problem that needs to be solved. Summary of the Invention

[0004] This application provides a method, terminal device, and network device for satellite handover in non-terrestrial networks. The various aspects involved in the embodiments of this application are described below.

[0005] In a first aspect, a method for satellite handover in a non-terrestrial network is provided, applied to satellite handover from a first satellite network coverage area to a second satellite network coverage area, comprising: receiving a first handover command, the first handover command including power-related information within the coverage area of ​​the second satellite network, and / or, relative position information of a second satellite corresponding to the second satellite network and a terminal device; and determining a first power for uplink transmission to the second satellite network based on the first handover command.

[0006] In a second aspect, a method for satellite handover in a non-terrestrial network is provided, comprising: applying satellite handover from a first satellite network coverage area to a second satellite network coverage area, including: confirming and determining a first handover command based on a handover request sent by the second satellite network, the first handover command including power-related information within the coverage area of ​​the second satellite network, and / or, relative position information of a second satellite corresponding to the second satellite network and a terminal device; sending the first handover command to the terminal device, the first handover command being used by the terminal device to determine a first power for uplink transmission to the second satellite network.

[0007] Thirdly, a method for satellite handover in a non-terrestrial network is provided, applied to satellite handover from a first satellite network coverage area to a second satellite network coverage area, comprising: sending a handover request confirmation to the first satellite network, the handover request confirmation being used by the first satellite network to determine a first handover command; wherein the first handover command includes power-related information within the coverage area of ​​the second satellite network, and / or, relative position information of a second satellite corresponding to the second satellite network and a terminal device, the first handover command being used by the terminal device to determine a first power for uplink transmission to the second satellite network.

[0008] Fourthly, a terminal device is provided, comprising: a receiving unit, configured to receive a first handover command, the first handover command instructing the terminal device to perform a satellite handover from a first satellite network coverage area to a second satellite network coverage area, the first handover command including power-related information within the second satellite network coverage area, and / or, relative position information of a second satellite corresponding to the second satellite network and the terminal device; and a determining unit, configured to determine a first power for uplink transmission to the second satellite network based on the first handover command.

[0009] Fifthly, a network device is provided, the network device being a network device corresponding to a first satellite network, the network device comprising: a determining unit, configured to confirm and determine a first handover command based on a handover request sent by a second satellite network, the first handover command being used to instruct a terminal device to perform a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network, the first handover command including power-related information within the coverage area of ​​the second satellite network, and / or, relative position information between the second satellite corresponding to the second satellite network and the terminal device; and a sending unit, configured to send the first handover command to the terminal device, the first handover command being used by the terminal device to determine a first power for uplink transmission to the second satellite network.

[0010] In a sixth aspect, a network device is provided, the network device being a network device corresponding to a second satellite network, the network device comprising: a transmitting unit, configured to send a handover request confirmation to a first satellite network, the handover request confirmation being used by the first satellite network to determine a first handover command, the first handover command being used to instruct a terminal device to perform a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network; wherein, the first handover command includes power-related information within the coverage area of ​​the second satellite network, and / or, relative position information between the second satellite corresponding to the second satellite network and the terminal device, the first handover command being used by the terminal device to determine a first power for uplink transmission to the second satellite network.

[0011] A seventh aspect provides a communication device including a memory and a processor, the memory for storing a program and the processor for calling the program in the memory to perform the method as described in any one of the first to third aspects.

[0012] Eighth aspect, an apparatus is provided, including a processor for calling a program from memory to perform the method as described in any one of the first to third aspects.

[0013] A ninth aspect provides a chip including a processor for calling a program from memory, causing a device having the chip mounted to perform the method as described in any one of the first to third aspects.

[0014] A tenth aspect provides a computer-readable storage medium having a program stored thereon that causes a computer to perform the method described in any one of the first to third aspects.

[0015] Eleventh aspect: A computer program product is provided, comprising a program that causes a computer to perform the method as described in any one of the first to third aspects.

[0016] In a twelfth aspect, a computer program is provided that causes a computer to perform the method described in any one of the first to third aspects.

[0017] In this embodiment, the first handover command received by the terminal device includes power-related information within the coverage area of ​​the second satellite network, and / or, the relative position information between the terminal device and the second satellite corresponding to the second satellite network. The power-related information can serve as a reference for the terminal device to determine or adjust the first power. The relative position information can improve the accuracy of the path loss estimated by the terminal device. Therefore, the first power determined by the terminal device takes into account the relevant conditions within the second satellite network, thereby improving the success rate of the terminal device accessing the second satellite network. Attached Figure Description

[0018] Figure 1 This is the wireless communication system used in the embodiments of this application.

[0019] Figure 2 This is an NTN system used in the embodiments of this application.

[0020] Figure 3 This is another NTN system used in the embodiments of this application.

[0021] Figure 4 This is a flowchart illustrating a method for NTN satellite handover provided in an embodiment of this application.

[0022] Figure 5This is a schematic diagram illustrating one method for determining the switching path loss of terminal devices.

[0023] Figure 6 This is a flowchart illustrating another method for NTN satellite handover provided in an embodiment of this application.

[0024] Figure 7 yes Figure 6 The flowchart illustrates one possible implementation of the method shown.

[0025] Figure 8 yes Figure 6 A flowchart illustrating another possible implementation of the method shown.

[0026] Figure 9 This is a schematic diagram of the structure of a terminal device provided in an embodiment of this application.

[0027] Figure 10 This is a schematic diagram of the structure of a network device provided in an embodiment of this application.

[0028] Figure 11 This is a schematic diagram of the structure of another network device provided in an embodiment of this application.

[0029] Figure 12 This is a schematic diagram of the structure of another terminal device provided in an embodiment of this application.

[0030] Figure 13 This is a schematic diagram of the structure of another network device provided in the embodiments of this application.

[0031] Figure 14 This is a schematic diagram of the structure of another network device provided in the embodiments of this application.

[0032] Figure 15 This is a schematic structural diagram of a communication device provided in an embodiment of this application. Detailed Implementation

[0033] The technical solutions of the embodiments of this application will now be described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art without creative effort regarding the embodiments of this application are within the scope of protection of this application.

[0034] The embodiments of this application can be applied to various communication systems. For example, the embodiments of this application can be applied to Global System for Mobile Communication (GSM), Code Division Multiple Access (CDMA), Wideband Code Division Multiple Access (WCDMA), General Packet Radio Service (GPRS), Long Term Evolution (LTE), Advanced Long Term Evolution (LTE-A), New Radio (NR), evolution systems of NR, LTE-based access to unlicensed spectrum (LTE-U), NR-based access to unlicensed spectrum (NR-U), NTN, Universal Mobile Telecommunication System (UMTS), Wireless Local Area Networks (WLAN), Wireless Fidelity (WiFi), and 5th-generation (5G) systems. The embodiments of this application can also be applied to other communication systems, such as future communication systems. These future communication systems could be, for example, sixth-generation (6G) mobile communication systems or satellite communication systems.

[0035] Traditional communication systems support a limited number of connections and are easy to implement. However, with the development of communication technology, communication systems can support not only traditional cellular communication but also one or more other types of communication. For example, a communication system can support one or more of the following communication methods: device-to-device (D2D) communication, machine-to-machine (M2M) communication, machine-type communication (MTC), enhanced machine-type communication (eMTC), vehicle-to-vehicle (V2V) communication, and vehicle-to-everything (V2X) communication. The embodiments of this application can also be applied to communication systems that support the above-mentioned communication methods.

[0036] The communication system in this application embodiment can be applied to carrier aggregation (CA) scenarios, dual connectivity (DC) scenarios, and standalone (SA) network deployment scenarios.

[0037] The communication system in this application embodiment can be applied to unlicensed spectrum. This unlicensed spectrum can also be considered a shared spectrum. Alternatively, the communication system in this application embodiment can also be applied to licensed spectrum. This licensed spectrum can also be considered a dedicated spectrum.

[0038] The embodiments of this application can be applied to NTN systems. As an example, the NTN system may include a 4G-based NTN system, an NR-based NTN system, an Internet of Things (IoT)-based NTN system, and a narrowband Internet of Things (NB-IoT)-based NTN system.

[0039] A communication system may include one or more terminal devices. The terminal devices mentioned in the embodiments of this application may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station (MS), mobile terminal (MT), remote station, remote terminal, mobile device, user terminal, terminal, wireless communication equipment, user agent, or user device, etc.

[0040] In some embodiments, the terminal device may be a station (ST) in a WLAN. In some embodiments, the terminal device may be a cellular phone, cordless phone, session initiation protocol (SIP) phone, wireless local loop (WLL) station, personal digital assistant (PDA) device, handheld device with wireless communication capabilities, computing device or other processing device connected to a wireless modem, in-vehicle device, wearable device, terminal device in a next-generation communication system (e.g., NR system), or terminal device in a future evolved public land mobile network (PLMN) network, etc.

[0041] In some embodiments, the terminal device may be a device that provides voice and / or data connectivity to a user. For example, the terminal device may be a handheld device, an in-vehicle device, etc., with wireless connectivity. As some specific examples, the terminal device may be a mobile phone, tablet, laptop, PDA, mobile internet device (MID), wearable device, virtual reality (VR) device, augmented reality (AR) device, wireless terminal in industrial control, wireless terminal in self-driving, wireless terminal in remote medical surgery, wireless terminal in smart grid, wireless terminal in transportation safety, wireless terminal in smart city, wireless terminal in smart home, etc.

[0042] In some embodiments, the terminal device may be deployed on land. For example, the terminal device may be deployed indoors or outdoors. In some embodiments, the terminal device may be deployed on water, such as on a ship. In some embodiments, the terminal device may be deployed in the air, such as on an airplane, balloon, or satellite.

[0043] In addition to terminal devices, the communication system may also include one or more network devices. In this embodiment, the network device can be a device for communicating with the terminal device; this network device may also be referred to as an access network device or a radio access network device. For example, the network device may be a base station. In this embodiment, the network device may refer to a radio access network (RAN) node (or device) that connects the terminal device to the wireless network. Base stations can broadly encompass various names listed below, or be replaced by names such as: NodeB, Evolved NodeB (eNB), Next Generation NodeB (gNB), Relay Station, Access Point, Transmitting and Receiving Point (TRP), Transmitting Point (TP), Master NodeB, Secondary NodeB (SeNB), Multimode Radio (MSR) Node, Home Base Station, Network Controller, Access Node, Wireless Node, Access Point (AP), Transmitting Node, Transceiver Node, Baseband Unit (BBU), Remote Radio Unit (RRU), Active Antenna Unit (AAU), Remote Radio Head (RRH), Central Unit (CU), Distributed Unit (CU) Base stations can be macro base stations, micro base stations, relay nodes, donor nodes, or similar entities, or combinations thereof. A base station can also refer to a communication module, modem, or chip installed within the aforementioned equipment or apparatus. A base station can also be a mobile switching center, equipment performing base station functions in D2D, V2X, and M2M communications, network-side equipment in 6G networks, or equipment performing base station functions in future communication systems. Base stations can support networks using the same or different access technologies. The embodiments of this application do not limit the specific technologies or equipment forms used in the network equipment.

[0044] Base stations can be fixed or mobile. For example, a helicopter or drone can be configured to act as a mobile base station, and one or more cells can move depending on the location of the mobile base station. In other examples, a helicopter or drone can be configured as a device to communicate with another base station.

[0045] In some deployments, the network device in this application embodiment may refer to a CU or a DU, or the network device may include both a CU and a DU. The gNB may also include an AAU.

[0046] By way of example and not limitation, in the embodiments of this application, the network device may have mobility characteristics; for example, the network device may be a mobile device. In some embodiments of this application, the network device may be a satellite or a balloon station. In some embodiments of this application, the network device may also be a base station located on land, water, or other similar locations.

[0047] In this embodiment, the network device can provide services to a cell. The terminal device communicates with the network device through the transmission resources (e.g., frequency domain resources, or spectrum resources) used by the cell. The cell can be the cell corresponding to the network device (e.g., a base station). The cell can belong to a macro base station or to a base station corresponding to a small cell. The small cell can include: metro cell, micro cell, pico cell, femto cell, etc. These small cells have the characteristics of small coverage area and low transmission power, and are suitable for providing high-speed data transmission services.

[0048] For example, Figure 1 This is a schematic diagram of the architecture of a communication system provided in an embodiment of this application. Figure 1 As shown, the communication system 100 may include a network device 110, which may be a device that communicates with a terminal device 120 (or a communication terminal, terminal). The network device 110 can provide communication coverage for a specific geographical area and can communicate with terminal devices located within that coverage area.

[0049] Figure 1 An exemplary diagram shows a network device and two terminal devices. In some embodiments of this application, the communication system 100 may include multiple network devices and each network device may include other numbers of terminal devices within its coverage area. This application does not limit the scope of the embodiments.

[0050] For example, Figure 2 This is a schematic diagram of an architecture of the NTN system mentioned above. Figure 2 The NTN system 200 shown uses satellite 210 as its airborne platform. For example... Figure 2 As shown, the satellite radio access network includes a satellite 210, a service link 220, a feeder link 230, terminal equipment 240, a gateway (GW) 250, and a network 260 including base stations and a core network.

[0051] Satellite 210 is a spacecraft based on a space platform. Service link 220 refers to the link between satellite 210 and terminal equipment 240. Feeder link 230 refers to the link between gateway 250 and satellite 210. The Earth-based gateway 250 connects satellite 210 to a base station or core network, depending on the chosen architecture.

[0052] Figure 2 The NTN architecture shown is a bend-type transponder architecture. In this architecture, the base station is located on Earth behind gateway 250, and satellite 210 acts as a relay. Satellite 210 operates as a relay that forwards signals from feeder link 230 to serving link 220, or forwards signals from serving link 220 to feeder link 230. That is, satellite 210 does not have the function of a base station; communication between terminal device 240 and the base station in network 260 needs to be relayed through satellite 210.

[0053] For example, Figure 3 This is a schematic diagram of another architecture for the NTN system. (Example:) Figure 3 As shown, the satellite radio access network 300 includes a satellite 310, a service link 320, a feeder link 330, terminal equipment 340, a gateway 350, and a network 360. Figure 2 The difference is that satellite 310 has base station 312, while the network 360 behind gateway 350 only includes the core network.

[0054] Figure 3 The NTN architecture shown is a regenerative transponder architecture. In this architecture, satellite 310 carries base station 312, which can be directly connected to the earth-based core network via a link. Satellite 310 functions as a base station, and terminal device 340 can communicate directly with satellite 310. Therefore, satellite 310 can be referred to as a network device.

[0055] exist Figure 2 and Figure 3 The communication system with the architecture shown may include multiple network devices, and each network device may include other terminal devices within its coverage area. This application embodiment does not limit this.

[0056] In the embodiments of this application, Figures 1 to 3 The communication system shown may also include other network entities such as a mobility management entity (MME) and an access and mobility management function (AMF), but this application does not limit this.

[0057] It should be understood that devices with communication functions in the network / system of this application embodiment can be referred to as communication devices. Figure 1Taking the communication system 100 shown as an example, the communication equipment may include a network device 110 and a terminal device 120 with communication functions. The network device 110 and the terminal device 120 may be the specific devices described above, which will not be repeated here. The communication equipment may also include other devices in the communication system 100, such as network controllers, mobility management entities and other network entities. This application embodiment does not limit this.

[0058] To facilitate understanding, some related technical knowledge involved in the embodiments of this application is first introduced. The following related technologies are optional solutions and can be arbitrarily combined with the technical solutions of the embodiments of this application, all of which fall within the protection scope of the embodiments of this application. The embodiments of this application include at least some of the following contents.

[0059] NTN system

[0060] With the development of communication technologies, communication systems (such as 5G) will integrate the market potential of satellite and terrestrial network infrastructure. For example, the 5G standard makes NTN, including satellite segments, part of the recognized 3rd Generation Partnership Project (3GPP) 5G connectivity infrastructure.

[0061] NTN refers to a network or network segment that uses radio frequency (RF) resources on satellite or unmanned aerial system (UAS) platforms. Taking satellites as an example, communication satellites are classified according to their orbital altitude into low Earth orbit (LEO) satellites, medium Earth orbit (MEO) satellites, geostationary Earth orbit (GEO) satellites, and highly elliptical orbit (HEO) satellites. LEO is a geocentric orbit with an altitude of 2000 kilometers or less, or at least 11.25 cycles per day, with an eccentricity of less than 0.25. Most man-made objects in outer space are located in LEO. LEO satellites orbit the Earth at high speeds (mobility), but in predictable or deterministic orbits.

[0062] Satellites at different orbital altitudes have different orbital periods.

[0063] LEO: Typical altitude is 250-1500 km, orbital period is 90-120 minutes.

[0064] MEO: Typical altitude is 5,000-25,000 km, and orbital period is 3-15 hours.

[0065] GEO: The altitude is approximately 35,786 kilometers, and the orbital period is 24 hours.

[0066] From the example of satellites mentioned earlier Figure 2 and Figure 3 It is known that typical scenarios for terminal devices accessing the NTN system involve NTN transparent payloads or NTN regenerated payloads. Among these, Figure 2 The bent-tube transponder architecture shown corresponds to the NTN transparent payload. Figure 3 The regenerative transponder architecture shown corresponds to the NTN regenerative payload.

[0067] In NTN systems, the propagation delay between terminal devices and network devices depends primarily on the altitude of the spaceborne or airborne platform and the type of payload within the NTN. Compared to terrestrial networks (TN), the propagation delay between terminal devices and network devices in NTN systems is significantly longer. For example, in traditional NR cellular networks, the propagation delay of terrestrial mobile systems is typically less than 1 millisecond, while the propagation delay in NTN systems ranges from several milliseconds to hundreds of milliseconds.

[0068] NTN systems offer strong mobility, and the coverage area provided by satellite and other aerial platforms is extensive, requiring terminal equipment to perform timely cell handovers to maintain stable communication. For simplicity, the following explanation will use satellite as an example.

[0069] In an NTN system, as satellites move, terminal equipment needs to perform satellite handover from the source NTN satellite (NTN1) to the target NTN satellite (NTN2). During the handover process, the terminal equipment typically starts two timers to enhance the timing relationship. These two timers are timer T304 and timer T430.

[0070] When the terminal device begins handover, it starts timer T304. During the handover process, once timer T304 expires, the terminal device initiates a radio resource control (RRC) connection re-establishment procedure with the target NTN cell.

[0071] During downlink (DL) and uplink (UL) synchronization, the terminal device starts timer T430. As mentioned earlier, the source satellite NTN1 and the terminal device on Earth will move relative to each other, thus raising the validity issue of the source satellite NTN1's auxiliary information (NTN-config). Timer T430 is used to ensure that the terminal device can continuously obtain valid source satellite NTN1 auxiliary information. For example, timer T430 can control the terminal device to obtain valid auxiliary information from the system information block (SIB) 19, ensuring that the source NTN1 auxiliary information obtained by the terminal device before the handover is completed is still valid.

[0072] The auxiliary information for the source satellite NTN1 includes satellite ephemeris and common timing advance (TA) parameters. For NTN1, the network side can broadcast ephemeris information and common TA parameters. For example, SIB19 includes satellite auxiliary information for NTN access. Before connecting to NTN2, the terminal device has a valid Global Navigation Satellite System (GNSS) position, satellite ephemeris information, and common TA.

[0073] No RACH handover (HO)

[0074] When synchronizing the source cell, target cell, and terminal device, a RACH-free handover solution can be introduced to reduce handover latency and improve user experience. In a synchronized network, the subframe boundaries between the source and target cells can be considered aligned. Therefore, the terminal device can hand over from the source cell to the target cell at a time agreed upon by all three parties, eliminating the need for a random access procedure. For example, when synchronizing the source cell, target cell, and terminal device, the terminal device can hand over from the source cell to the target cell using the agreed-upon system frame number (SFN) without requiring random access.

[0075] One of the main purposes of the random access channel (RACH) procedure during handover is to obtain the target cell's touchpoint (TA). With RACH handover in progress, the terminal device can obtain the TA of the target cell through the RACH procedure. Without the RACH procedure, when the source and target cells are time-synchronized, the terminal device can obtain the target cell's TA without an explicit TA command.

[0076] Another objective of the RACH procedure during handover is to obtain uplink granted transmissions. In the absence of a RACH procedure in the target cell, uplink grants need to be allocated within the target cell. In some embodiments, for the initial UL transmission in a RACH-free handover, pre-allocation of grants in the RACH-free handover command is supported. That is, the target cell can pre-allocate uplink grants (UL-grants) through the handover command. The pre-allocated uplink grants can remain valid for a period of time, starting from the point where the terminal device achieves synchronization with the target cell. For example, during a RACH-free handover in an NR terrestrial network, the propagation delay between the terminal device and network devices is low. Based on the propagation delay information between the terminal device and network devices, the target cell can appropriately configure the temporal location of uplink resources in the handover command to facilitate the sending of an RRCReconfigurationComplete message (i.e., a handover completion message) when the terminal device accesses the target cell.

[0077] For the initial UL transmission in a RACH-free handover, pre-allocation authorization in the RACH-free handover command needs to be supported. In the NTN system, RACH-free handover is supported regardless of whether the handover occurs within satellites with the same feeder link or within satellites with different feeder links. Satellites with the same feeder link refer to those with the same gateway or network equipment (e.g., gNB).

[0078] In a RACH-less handover process, due to the lack of RACH preamble transmission and random access response reception, the terminal device may set the initial transmit power to an inappropriate level due to incorrectly estimated path loss. For example, when the terminal device receives information about UL authorization, it may fall into a logical deadlock, leading to handover failure. For instance, the terminal device may have confirmed UL authorization, but due to low transmit power, the network device cannot receive uplink transmissions, and the response message always fails.

[0079] In a RACH-less handover, if the initial transmission power of the terminal device's uplink transmission is directly referenced to the power control rules of the licensed physical uplink shared channel (PUSCH) used for configuration, there may be problems such as uncertain path loss and inapplicable power adjustment.

[0080] For example, in RACH-free handovers, grants are pre-allocated or dynamically granted, and the determination of path loss is unclear or inaccurate. In NTN systems, satellites are at high altitudes and cover large areas, so inaccurate path loss estimates have a significant impact on power. In some scenarios, if the two satellites being handed over are of different types and have significantly different altitudes, this can also affect the accuracy of path loss estimation.

[0081] For example, for PUSCH power adjustment and power control adjustment, since the current specification has conditions such as "if the UE receives a random access response message in response to PRACH transmission", power adjustment and power control adjustment based on PRACH transmission power are not applicable to handover without RACH.

[0082] In summary, when introducing RACH-free handover in NTN scenarios, how terminal devices determine the initial transmission power for uplink transmission within pre-allocated resources to improve the success rate of handover access becomes a problem that needs to be solved.

[0083] It should be noted that the problem mentioned above, where the transmission power is unsuitable due to uncertain path loss and inability to trigger power control adjustment via PRACH when introducing RACH-less handover in NTN system, is only an example. The embodiments of this application can be used in any type of handover scenario where the path loss in the transmission power is uncertain or the power adjustment cannot be triggered.

[0084] To address the aforementioned issues, this application proposes a method for NTN satellite handover. This method allows a first handover command to include power-related information within the coverage area of ​​the second satellite network and / or the relative location information of network devices and terminal devices corresponding to the second satellite network. This enables the terminal device to determine a first power for uplink transmission to the second satellite network. Therefore, the first power takes into account the communication or location conditions of the second satellite network, helping to improve the accuracy of the first power and thus increasing the handover success rate.

[0085] To facilitate understanding, the following will be combined with... Figure 4 A method proposed in the embodiments of this application will be described in detail. Figure 4 The method shown is executed by the terminal device. Figure 4 The method shown is used for satellite handover from a first satellite network coverage area to a second satellite network coverage area.

[0086] The terminal device can be any of the terminal devices described above. In some embodiments, the terminal device is a communication device providing services to satellites in the NTN system. In some embodiments, the terminal device is a communication device with a low service transmission rate.

[0087] The first and second satellite networks are NTN networks that integrate ground facilities and aerial platforms such as satellites. As mentioned earlier, the aerial platforms such as satellites in the first and second satellite networks can provide services as network equipment or as relays. Taking satellites as an example, the network equipment corresponding to the first and second satellite networks can be satellites or ground base stations. For simplicity, the satellites corresponding to the first satellite network can be referred to as the first satellite, and the satellites corresponding to the second satellite network can be referred to as the second satellite. The network equipment corresponding to the first satellite network can be referred to as the first network equipment, and the network equipment corresponding to the second satellite network can be referred to as the second network equipment.

[0088] The first satellite network is the NTN network currently providing services to the terminal devices. The first satellite network can also be referred to as the source NTN or source satellite network. In some embodiments, the first satellite network provides services to terminal devices within its coverage area through its corresponding network equipment.

[0089] The network equipment corresponding to the first satellite network is the communication equipment that provides services to the terminal device at the current moment. In some embodiments, the network equipment may be a device that moves relative to the terminal device. For example, the first network equipment may be a base station on a satellite that provides services to the terminal device. Alternatively, the first network equipment may be a base station installed on a low-altitude aircraft. In some embodiments, the network equipment may be a device that is stationary relative to the terminal device or the Earth. For example, when a satellite in the first satellite network acts as a relay, the first network equipment may be a ground-based base station that communicates with the satellite through a gateway.

[0090] The first satellite network coverage area is the area where the first satellite network provides communication services. In some scenarios, the first satellite network coverage area may also be referred to as the source cell. In some embodiments, the first satellite network coverage area may include one or more terrestrial network cells.

[0091] The second satellite network is an NTN network that provides services to terminal devices after the first satellite network. The second satellite network may also be referred to as a target NTN or target satellite network. In some embodiments, the second satellite network provides services to terminal devices within its coverage area through its corresponding network devices. In some embodiments, the first satellite network may determine multiple satellite networks that can provide services to terminal devices based on satellite motion trajectories and / or ephemeris information, and then determine a second satellite network. In some embodiments, the terminal device may determine the second satellite network from multiple candidates through signal measurements.

[0092] The network equipment corresponding to the second satellite network is the next communication equipment to provide services to the terminal device. In some embodiments, the second network equipment may be a device that moves relative to the terminal device, or it may be a device that is stationary relative to the terminal device or relative to the Earth, which will not be elaborated further here.

[0093] The second satellite network coverage area is the area where the second satellite network provides communication services. In some scenarios, the second satellite network coverage area may also be referred to as the target cell. In some embodiments, the second satellite network coverage area may include one or more terrestrial network cells.

[0094] Satellite handover can be a handover of satellites corresponding to the area where the terminal device is located. For example, satellite handover can be cell handover. For example, the physical cell identity (PCI) of the coverage area can remain unchanged during satellite handover.

[0095] See Figure 4 In step S410, the first switching command is received.

[0096] The terminal device receives a first handover command from a first satellite network. The first satellite network can confirm the first handover command based on a handover request sent by a second satellite network.

[0097] The first handover command can be used to determine the first power for uplink transmission from the terminal device to the second satellite network. In some embodiments, the first handover command can be a handover command without RACH. In some embodiments, the first handover command can be a handover command for other handover methods without a random access response.

[0098] The uplink transmission from the terminal device to the second satellite network can be the initial uplink transmission described above, or other uplink transmissions sent by the terminal device to the second satellite network. For example, the uplink transmission is a PUSCH transmission.

[0099] Uplink transmissions can be performed on the first resources pre-configured in the second satellite network. In some embodiments, for PUSCH transmissions without reserved resources during RACH handover, a synchronization signal block (SSB) or a synchronization signal and PBCH block (SS / PBCH block) can be associated with the initial PUSCH transmission. That is, for pre-allocated initial PUSCH transmissions, the SSB can be determined before the PUSCH resources are determined. For simplicity, SSB in the following text can refer to either a synchronization signal block or a synchronization signal and PBCH block.

[0100] The first power can be the transmit power of the terminal device sending its initial uplink transmission, or the initial transmission power of the terminal device communicating with the second satellite network. As mentioned earlier, in an NTN, if the terminal device does not perform a random access procedure during handover, and there is no random access response as a reference when determining the first power, inaccurate path loss estimation or unreasonable power adjustment may occur. Therefore, the first handover command may include relevant information for the terminal device to determine the initial transmission power, in order to improve the accuracy of path loss estimation and / or the rationality of power adjustment.

[0101] To improve the accuracy of the first power rating, the first handover command may include power-related information within the coverage area of ​​the second satellite network, and / or the relative position information between the second satellite and the terminal device corresponding to the second satellite network. Information related to communication parameters within the coverage area of ​​the second satellite network may be carried in the handover request confirmation sent by the second satellite network.

[0102] Power-related information within the coverage area of ​​the second satellite network can represent the power parameters for communication between the second satellite network and terminal devices within the area. When terminal devices determine their initial power based on these power parameters, they can obtain a more suitable power value for accessing the second satellite network, thereby improving the access success rate.

[0103] In some embodiments, power-related information within the coverage area of ​​the second satellite network may include one or more of the following parameters: the average signal quality of some or all uplink beams accessing the area; the maximum signal quality of some or all uplink beams accessing the area; the transmit power of at least some of the terminal devices already accessed in the area transmitting random access uplink channels; the average admission power of terminal devices other than the terminal devices in the second satellite network; the maximum admission power of terminal devices other than the terminal devices in the second satellite network; the average path loss within the coverage area of ​​the second satellite network; and the maximum path loss within the coverage area of ​​the second satellite network.

[0104] For example, power-related information may also include the signal quality of the beam associated with no RACH switching.

[0105] For example, the signal quality can be one or more of the following: reference signal received power (RSRP), reference signal received quality (RSRQ), and reference signal strength indication (RSSI).

[0106] The part or all of the uplink beams used for access within the coverage area of ​​the second satellite network refers to part or all of the uplink beams received by the second satellite network within the coverage area. In some embodiments, part of the uplink beams may be the uplink beams of other terminal devices located near the terminal device.

[0107] For example, when a handover request confirms the average signal strength (e.g., RSRP) of some or all uplink beams within the coverage area received by the second satellite network, the terminal device can obtain this average value via a first handover command. The terminal device can then estimate the transmit power it needs to achieve that strength at its current location based on this average value, using it as the first power level for handover to the second satellite network.

[0108] For example, when a handover request confirms the maximum value of the signal strength (e.g., RSRP) of some or all uplink beams within the coverage area received by the second satellite network, the terminal device can obtain this maximum value through a first handover command. The terminal device can then estimate the transmit power it needs to achieve that strength at its current location based on this maximum value, using it as the first power level for handover to the second satellite network. By determining the first power based on the maximum value, the problem of insufficient transmit power leading to no response can be effectively solved.

[0109] The beams associated with RACH-free handover within the coverage area of ​​the second satellite network refer to the beams reserved for RACH-free handover within the coverage area received by the second satellite network. In some embodiments, these associated beams may be SSB beams. For example, the path loss reference signal for PUSCH transmission may be a reference signal for the SSB used to determine reserved PUSCH resources.

[0110] For example, when the handover request confirms the signal strength (e.g., RSRP) of the reserved beam associated with no RACH handover within the coverage area received by the second satellite network, the terminal device can obtain this value through a first handover command. The terminal device can estimate the transmit power it needs to achieve that strength at its current location based on this maximum value, as the first power level for the terminal device to handover to the second satellite network.

[0111] For example, for an initial PUSCH transmission based on a dynamic grant (DG), the second satellite network can directly indicate the SSB via the physical downlink control channel (PDCCH). Since there is no random access procedure, the path loss reference for power control of the initial PUSCH transmission can be the SSB associated with the initial PUSCH transmission.

[0112] The transmit power of random access uplink channels transmitted by at least a portion of the terminal devices already connected within the coverage area of ​​the second satellite network refers to the power received by the second satellite network within the coverage area via the physical random access channel (PRACH). In some embodiments, these parameters can be determined based on the initial nominal power of the PUSCH. The initial nominal power of PUSCH transmission can be configured in the RRC in the same manner as conventional methods. In some embodiments, the initial nominal power of PUSCH transmission may not be configured, and these parameters can be determined as the initial target receive power of the PRACH in the second satellite network. Although the PRACH is not initiated by the terminal device performing a RACH-less handover, it can be read from the system information block (SIB) of the second satellite network.

[0113] For example, the terminal device can read the initial target receive power of the PRACH of other terminal devices in SIB1 of the second satellite network as a reference for determining the first power.

[0114] For example, in a RACH-free handover, since there is no random access procedure, the transmit power of the random access uplink channel can be the transmit power of at least some terminal devices sending message A (msgA), or it can be the transmit power of at least some terminal devices sending message 3 (msg3). That is, the first power is determined based on the transmit power of message A and / or message 3 sent by other terminal devices. For example, the reference could be the average or maximum value of the transmit power of message A sent by some terminal devices. Alternatively, the reference could be the average or maximum value of the transmit power of message A sent by all terminal devices.

[0115] The average or maximum access power of terminal devices other than the terminal devices in the second satellite network refers to the average or maximum access power that the second satellite network allows other terminal devices to access. For terminal devices, the relevant parameters of access power can be used as a reference for the first power. For example, when a terminal device's service needs to access the second satellite network in a timely manner, the first power can be equal to or close to the maximum access power. Alternatively, the first power can be equal to the average value for initial uplink transmission.

[0116] For example, the terminal devices other than the terminal devices can be some or all of the terminal devices in the second satellite network, without limitation.

[0117] For example, some terminal devices may be other terminal devices that are geographically close to the terminal device.

[0118] The average or maximum path loss within the coverage area of ​​the second satellite network refers to the average or maximum path loss of the network devices corresponding to the second satellite network communicating with other terminal devices. Both can be used to determine the path loss in the first power.

[0119] In some embodiments, the determination of the first power also needs to consider the maximum output power of the terminal device. The first power may be less than or equal to a specific percentage of the maximum output power (e.g., 80%). Exemplarily, the first power is determined based on power-related information in the first handover command and the maximum output power of the terminal device. For example, if the maximum output power is less than the maximum value of the admission power, the first power may be determined with reference to an average value.

[0120] In step S420, based on the first handover command, the first power for uplink transmission to the second satellite network is determined. The above section introduced various possible implementations for determining the first power in conjunction with the information in the first handover command, which will not be repeated here. The following section briefly introduces the calculation method for PUSCH transmission power.

[0121] The first handover command may also include the relative position information between the second satellite corresponding to the second satellite network and the terminal device, in order to determine the path loss compensation factor of the terminal device in the second satellite network. The second satellite is the satellite corresponding to the second satellite network, and the first satellite is the satellite corresponding to the first satellite network.

[0122] The path loss of a terminal device differs between the first and second satellite networks, and the path loss is related to both distance and frequency. The path loss compensation factor for the terminal device in the second satellite network can be used to compensate for the path loss in the second satellite network. For simplicity, the path loss compensation factor for the terminal device in the first satellite network can be referred to as the first path loss compensation factor, and the path loss compensation factor in the second satellite network can be referred to as the second path loss compensation factor.

[0123] In some embodiments, the second path loss compensation factor can be carried in the first handover command sent by the first satellite network to the terminal device. That is, after the second satellite network determines the second path loss compensation factor, it can directly send it to the terminal device through the first handover command.

[0124] In some embodiments, relative position information may include the distance between the terminal device and the second satellite. Path loss can be estimated based on this distance parameter. This distance can be determined using the position coordinates of the terminal device and the second satellite. Exemplarily, the position coordinates of the terminal device can be obtained through GNSS position information or other means. The first satellite network can send the position information of the terminal device to the second satellite network via a handover request message. The position information of the second satellite can be determined using satellite ephemeris information.

[0125] In some embodiments, the relative position information may include the azimuth angle between the terminal device and the second satellite. The azimuth angle can also be called the orientation angle. It can be the angle between the line connecting the terminal device and the satellite and the perpendicular line from the satellite to the ground, that is, the azimuth angle between the terminal device and the satellite perpendicular to the ground. The azimuth angle can also be determined based on the position of the terminal device and the position of the second satellite.

[0126] In some embodiments, the relationship between the path loss from the terminal device to the first satellite network and the second satellite network can be used to determine the second path loss compensation factor.

[0127] For example, the path loss compensation factor of the terminal device in the second satellite network can be determined by the azimuth angle of the terminal device in the first satellite network and the azimuth angle of the second satellite network. When the second path loss compensation factor is represented by K, K can be determined according to the following formula:

[0128]

[0129] Wherein, δ1 represents the azimuth angle between the terminal device and the first satellite corresponding to the first satellite network, and δ2 represents the azimuth angle between the terminal device and the second satellite.

[0130] To facilitate understanding, the following will be combined with... Figure 5 The method for determining the second path loss compensation factor is illustrated below. (See attached image.) Figure 5 Satellite 510 is the first satellite corresponding to the first satellite network, and satellite 520 is the second satellite corresponding to the second satellite network. Terminal device 530 performs satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network.

[0131] like Figure 5 As shown, the distance between terminal device 530 and satellite 510 is D1, and the azimuth angle is δ1. The distance between terminal device 530 and satellite 520 is D2, and the azimuth angle is δ2. The first satellite network and the second satellite network can obtain the azimuth angles δ1 and δ2 between terminal device 530 and satellites 510 and 520 perpendicular to the ground using the position coordinate information of terminal device 530.

[0132] The above section introduced several methods for determining the second path loss compensation factor K. Based on the value of K, the first power of the terminal device can be determined. For example, the first power P of the terminal device for uplink transmission on the uplink bandwidth b of carrier f in serving cell c is... PUSCH,b,f,c It can be determined using the following formula:

[0133]

[0134] Where i represents the transmission timing, j represents the index of the parameter set configuration, and q d The index represents the reference signal, l represents the index of the power control adjustment state, μ is related to the subcarrier spacing, and P CMAX,f,c (i) represents the maximum output power of the terminal device in the second satellite network. This indicates the current transmit power of the terminal device within the first satellite network. Indicates uplink resource bandwidth, α b,f,c (j) represents the path loss compensation factor of the terminal device within the first satellite network, PL b,f,c (q d ) represents the downlink path loss, Δ TF,b,c,f (i) represents the power adjustment amount, f b,f,c (i,l) represents the power control adjustment state. Optionally, This can be the number of resource blocks.

[0135] Optionally, μ can be a subcarrier spacing configuration supported by the protocol, which can adjust bandwidth resources under different subcarrier spacing configurations, thereby achieving corresponding power adjustment.

[0136] As mentioned above, α b,f,c (j) can be the first path loss compensation factor estimated by the current terminal device in the first satellite network.

[0137] Optionally, PL b,f,c (q d This parameter can be the downlink path loss obtained by the terminal device through measuring the downlink reference signal. This parameter can be determined using the results of an evaluation by the first satellite network, or based on information from the second satellite network in the first handover command sent by the first satellite network.

[0138] Optionally, the terminal device calculates PL b,f,c (q dWhen the terminal device obtains the master information block (MIB), it can use the reference signal (RS) resource from the SS / PBCH block. The index of this SS / PBCH block is the same as the index of the SS / PBCH block from which the terminal device obtains the master information block (MIB).

[0139] Optionally, the terminal device calculates PL b,f,c (q d When this occurs, RS resources from the SS / PBCH block can be used. The index of the SS / PBCH block corresponding to this RS resource is the same as the index of the SS / PBCH block used by the terminal device to monitor the PDCCH dynamic scheduling UL authorization. The UL authorization for this PDCCH dynamic scheduling is used for the initial transmission.

[0140] Δ TF,b,c,f (i) can be determined using the value of the pre-leader power boost counter (PREAMBLE_POWER_RAMPING_COUNTER).

[0141] Optionally, f b,f,c (i,l) can represent the PUSCH power control adjustment state of the uplink bandwidth part b corresponding to the carrier f of the first satellite network during PUSCH transmission time i. The power control adjustment state value includes the transmit power control (TPC) command value in the downlink control information (DCI) format. The power control adjustment state value can also be co-encoded with other TPC commands in DCI format 2_2, where the cyclic redundancy check (CRC) is scrambled by TPC-PUSCH-RNTI.

[0142] Optionally, This represents the current transmit power value of the terminal device. If the terminal device is in an RRC connected state, the handover request confirmation information from the second satellite network to the first satellite network may include the ConfiguredGrantConfig information sent by the second satellite network to the terminal device. This information may involve resources, beam indexes, and parameters such as the average path loss or maximum path loss within the second satellite network.

[0143] The preceding text introduced a method for determining the first power based on the second path loss compensation factor K. As mentioned earlier, the first handover command can be a RACH-free handover command. When a satellite handover is performed without RACH, the preamble power boost counter described earlier may fail to determine the power adjustment amount for the second satellite network. The power boost in the preamble power boost counter is related to the PUSCH and / or PRACH of the first satellite network message A. The PUSCH and / or PRACH of the first satellite network message A use the same spatial transmission beam. However, the parameters in the second satellite network cannot be correlated with this counter.

[0144] To address this issue, a new power adjustment counter P can be used. The power adjustment counter P can be a counter corresponding to a no-RACH system and can be used to determine the amount of power adjustment in the first power. In some embodiments, the value of the power adjustment counter P can be related to parameters of the terminal device accessing the first satellite network. In some embodiments, the value of the power adjustment counter P can be related to the number of random accesses by the terminal device. For example, the value of the power adjustment counter P is the number of accesses by the terminal device establishing a connection with the first satellite network.

[0145] In some embodiments, the power adjustment amount in the first power can also be determined based on a power adjustment factor. This power adjustment factor is, for example, N, where N is a positive integer greater than 1.

[0146] For example, the power adjustment factor N can be determined based on the service type of the terminal device. That is, N is related to the service type. For instance, the higher the quality of service (QoS) requirement, the larger the value of N can be.

[0147] For example, during handover, the power adjustment amount from the first satellite network cannot be reused. To ensure a smooth handover to the second satellite network, the transmit power needs to be relatively high. Although this may cause some interference to other nearby terminal devices, it ensures a high success rate for access. Once the terminal device sends a handover success message, indicating that a communication link has been established with the second satellite network, its transmit power will decrease. Even without receiving a TPC adjustment command in the PDCCH, the terminal device will still reduce its transmit power according to the new power adjustment counter.

[0148] The method for determining the power adjustment factor N has been described above. Based on the value of N, the first power of the terminal device can be determined. For example, the first power P of the terminal device for uplink transmission on the uplink bandwidth b of carrier f in serving cell c is... PUSCH,b,f,c It can be determined using the following formula:

[0149]

[0150] Where N represents the power adjustment factor, and N > 1. Other parameters have been introduced above and will not be repeated here.

[0151] Optionally, the first power of the terminal device can comprehensively consider path loss and power adjustment. For example, the first power P of the terminal device for uplink transmission on the uplink bandwidth b of carrier f in serving cell c is... PUSCH,b,f,c It can be determined using the following formula:

[0152]

[0153] Where K represents the second path loss compensation factor and N represents the power adjustment factor.

[0154] Combined with the preceding text Figure 4 and Figure 5 This paper introduces a method and implementation example for improving the handover success rate by introducing RACH-free handover in an NTN system and determining the transmit power after receiving the handover command. The terminal equipment typically performs uplink transmissions on pre-configured or dynamically scheduled uplink resources of a second satellite network.

[0155] Compared to cellular networks used in some communication systems (e.g., NR), the propagation delay between terminal devices and satellites is greater in NTN, resulting in a larger propagation delay for the portion of the air interface where the terminal device correctly receives the handover command. When introducing RACH-less handover in an NTN system, the large propagation delay may cause the terminal device to miss configured uplink resources during the process of accessing the target cell, leading to handover failure. For example, in RACH-less handover in NTN, due to the delay in the handover command from the target satellite to the terminal device, the source satellite may also experience radio link control (RLC) layer retransmission or hybrid automatic repeat reQuest (HARQ) retransmission when forwarding the handover command, further increasing the propagation delay of this portion of the air interface for the terminal device, thus preventing successful access.

[0156] In some scenarios, NTN achieves coverage based on beams, just like other communication systems (e.g., 5G(NR)). For example, each serving cell carries one or more SSB beams.

[0157] SSB beams are typically static or semi-static. The maximum number of SSB beams per cell ranges from 4 to 64, forming a (beam) grid covering the entire cell. Typically, after powering on, the terminal equipment searches for and measures beams, maintaining a set of candidate beams. This candidate beam set can contain beams from multiple cells. The terminal equipment can measure the beam signal to determine beam quality. For example, the terminal equipment can measure the RSRP of the synchronization signal (SS), i.e., SS-RSRP. It can also measure the RSRQ based on the synchronization signal, i.e., SS-RSRQ. Furthermore, the terminal equipment can measure the signal-to-noise and interference ratio (SINR) of the beam based on the synchronization signal, i.e., SS-SINR.

[0158] In some embodiments, a network device (e.g., a gNB) can determine the appropriate beam based on a layer 3 (L3) measurement report or a location report from an end device. The L3 measurement report includes beam level results. However, in some cases, the network device may not have this information, such as when there is no location report available.

[0159] As mentioned earlier, in RACH-free handover, grants are pre-allocated. If the appropriate beam for the terminal device cannot be determined, allocating grants on all beams of the target cell will result in resource issues, while allocating grants on only some beams may cause the terminal device to miss the configured uplink resources.

[0160] For example, in an NTN, the target NTN2 cannot know the beam associated with the terminal device without a location report or L3 measurement report, or the appropriate beam may change before or during the RACH handover process, thus making it impossible to pre-configure appropriate uplink resources.

[0161] For example, when conditional handover (CHO) is combined with non-RACH handover, the timing of the handover is uncertain, and suitable uplink resources may not be pre-configured.

[0162] In summary, when introducing RACH-free handover in NTN scenarios, how to reserve and pre-configure uplink resources in the RACH-free handover command to improve the success rate of terminal device handover access becomes a problem that needs to be solved.

[0163] It should be noted that the above-mentioned problem of handover failure due to large propagation delay and inappropriate reserved resource configuration when introducing RACH-free handover in NTN system is only an example. The embodiments of this application can be applied to any type of handover scenario where the propagation delay is large and the terminal device cannot communicate with the target cell through random access.

[0164] Based on this, this application proposes another method for NTN satellite handover. Using this method, the terminal device can send a selected beam or beam measurement information to the target satellite network before cell handover, so that the target satellite network can configure uplink resources on the appropriate beam based on this information, thereby improving the handover success rate.

[0165] To facilitate understanding, the following will be combined with... Figure 6 Another method proposed in the embodiments of this application will be described in detail. Figure 6 It was written from the perspective of the interaction between terminal devices, the first satellite network, and the second satellite network. Figure 6 The method shown is also applicable to satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network. For simplicity, Figure 4 The terminology explanations in the course of Figure 6 The lieutenant general will not elaborate further.

[0166] See Figure 6 In step S610, the terminal device sends the first information to the first satellite network.

[0167] The first information is used by the second satellite network to determine the first beam corresponding to the terminal device, so that the second satellite network can pre-configure the terminal device with a first resource for satellite handover. This first beam is also used by the second satellite network to schedule a second resource. In other words, the first beam is associated with the first and / or second resources of the second satellite network used for satellite handover.

[0168] In some embodiments, the first resource may be a configured or pre-configured resource. For example, the first resource is a reserved resource for the terminal device to perform satellite handover. Alternatively, the first resource may include uplink authorization for satellite handover.

[0169] In some embodiments, the second resource may be a scheduled uplink resource. This uplink resource may be dynamically scheduled.

[0170] For example, the first resource is a reserved resource for satellite handover, and the second resource is a scheduled uplink resource used by the terminal device to perform satellite handover. For instance, the first resource can be a reserved resource for the terminal device to send the initial uplink transmission, and the second resource can be a resource dynamically scheduled through PDCCH.

[0171] The first beam is one of all beams used by the second satellite network to cover the service area. In some embodiments, the first beam may be a single beam. In some embodiments, the first beam may be multiple beams. Typically, the number of beams in the first beam is less than the total number of beams in the second satellite network, so the second satellite network allocates uplink resources only on a subset of beams, effectively saving resources.

[0172] Terminal devices can determine multiple beams of a second satellite network in various ways. In some embodiments, prior to the handover process, after the first satellite network informs the terminal device of the target satellite network (i.e., the second satellite network), the terminal device can determine multiple beams of the second satellite network through measurement. In some embodiments, prior to the handover process, the first satellite network can provide the terminal device with information indicating multiple beams in the second satellite network. This information can identify multiple beams, or beam information can be identified by identifying reference signals transmitted via the beams. For example, the terminal device can identify beam information via SSB. Alternatively, after receiving this information, the terminal device can identify and measure one or more characteristics of the reference signal to determine the beam. These one or more characteristics are, for example, power, RSRP, RSRQ, etc.

[0173] The first beam can be one or more beams through which the terminal device can access the second satellite network, or it can be an appropriate beam for subsequent communication between the terminal device and the second satellite network. In other words, the terminal device can establish communication with the second satellite network through the first beam. When the second satellite network configures or pre-configures the first resource for satellite handover on the first beam, the terminal device can better utilize these resources for network access, thereby improving the success rate of satellite handover while avoiding resource waste.

[0174] The first beam is associated with a first resource pre-configured by the second satellite network for satellite handover. For example, the second satellite network allocates authorization for satellite handover on the first beam. The second satellite network may reserve resources associated with the first beam and include information related to the resource reservation in the handover request confirmation sent to the first satellite network.

[0175] The first resource can be the time-frequency resources reserved by the second satellite network for satellite handover of terminal devices. For example, the first resource can be used for the initial uplink transmission of the terminal device during handover without RACH. Since the terminal device only uses these resources during handover, the first resource is usually pre-configured by the second satellite network. It should be understood that in some scenarios, the second satellite network can also dynamically configure the first resource.

[0176] In some embodiments, the first resource may include one or more pre-assigned licenses. For example, a terminal device may access the network through these pre-assigned licenses.

[0177] The second resource can be a resource scheduled by the second satellite network according to communication needs to facilitate uplink transmission by the terminal device. In some embodiments, the second resource can be an uplink resource dynamically scheduled by the second satellite network. In some embodiments, the second resource can be an uplink resource scheduled in real time by the second satellite network.

[0178] For example, the second satellite network may transmit PDCCH on the first beam. For instance, in a RACH-free handover, the second satellite network does not transmit the Media Access Control Control Element (MAC CE) that resolves contention for terminal equipment, but instead transmits a PDCCH or Physical Downlink Shared Channel (PDSCH) that can be addressed to the Cell-Radio Network Temporary Identifier (C-RNTI).

[0179] For example, before completing a RACH-free handover, the MAC entity may not select an uplink grant for the logical channel corresponding to the data radio bearer (DRB). This uplink grant is used for the uplink grant of the HARQ procedure during the initial UL transmission. If a PDCCH addressed to the C-RNTI-scheduled DL / UL is received after the initial UL transmission, the RACH-free handover is considered complete.

[0180] In some embodiments, the first resource may include one or more pre-assigned uplink (UL) grants. These grants can be used by the terminal device to access the network. For example, based on measurement reports, a second satellite network may provide one or more UL grants to the terminal device. Each of the one or more UL grants may be associated with a first beam in the second satellite network.

[0181] For example, the terminal device can send an initial uplink transmission using available UL authorizations (RRC, MAC, PHY). The initial uplink transmission includes messages such as RRCReconfigurationComplete.

[0182] In some embodiments, the first resource may also be associated with the SSB index of the first beam, so that the terminal device can determine the beam in which the first resource is located through the SSB index. For example, the first beam may also be used to carry one or more synchronization signal blocks for satellite handover by the terminal device. The index of the one or more synchronization signal blocks is associated with the first resource.

[0183] For example, the first information may also include the index of one or more SSBs measured by the terminal device. The second satellite network can determine the first beam through the SSB index. When a single SSB is mapped to a beam, because the beam coverage is much larger than the TN and different frequency reuse patterns are considered between beams, the SSB detectable at a specific time point and the UE's location will represent the appropriate beam for subsequent communication. However, in an NTN, there may be one or more SSBs associated with a single beam. If multiple SSBs are mapped to a single beam, the channel quality is nearly similar or identical because the same satellite setup and propagation are shared. In this case, the terminal device may be unable to perform SSB selection during RACH-free handover. To address this issue, when the second satellite network allocates the first beam for the terminal device to use for RACH-free handover, the first beam can be associated with an SSB index. The terminal device can then know the reservation information related to pre-allocated resources associated with this SSB index.

[0184] For example, the second satellite network can specify one or more SSB index-related authorizations. The SSB index-related authorizations indicate the SSBs available without RACH handover and their corresponding resources. If the terminal device connects to these SSBs, it can directly perform synchronization and network access.

[0185] The first information may include various types of content to facilitate the second satellite network in determining the first beam. In some embodiments, the first information may directly indicate the first beam selected by the terminal device. That is, the terminal device may determine a suitable first beam on its own and then inform the second satellite network through the first satellite network. For example, the terminal device may measure multiple beams of the second satellite network, determine the first beam based on the measurement results, and then directly inform the second satellite network of this information through the first information. In some embodiments, the first information may include multiple first measurement results from the terminal device's measurement of multiple beams of the second satellite network. The multiple first measurement results are used by the second satellite network to determine the first beam. That is, the first information may also be a measurement report. For example, the terminal device may measure the respective strengths of reference signals, generate respective measurement reports, and provide the measurement reports to the second satellite network.

[0186] In some embodiments, when a terminal device selects a beam, the beam selection can be periodic, aperiodic, or triggered. During satellite handover, through pre-allocated authorization and the association between the beam or SSB, the second satellite network can know the beam selected by the terminal device and use the corresponding beam to schedule subsequent transmissions.

[0187] The first measurement result can be the result of the terminal device measuring the reference signal of the beam. In some embodiments, the reference signal can be the synchronization block reference signal (SSB-RS), or the RS of channel state information (CSI), i.e., CSI-RS, or a combination of CSI-RS and SSB-RS.

[0188] The first measurement result can be used to represent the signal quality of the beam reference signal. Signal quality can also be referred to as signal strength. To indicate signal quality, the first measurement result can be any one of the RSRP, RSRQ, RSSI, and SINR mentioned above, or multiple of them.

[0189] In some embodiments, the terminal device or the second satellite network may determine the first beam based on multiple first measurement results and / or a first threshold. The first threshold may be set by the terminal device or by the second satellite network. In some embodiments, the terminal device and the second satellite network may share this parameter through the first satellite network so that the first beams determined by both are the same or similar.

[0190] For example, the first measurement result corresponding to the first beam can be the maximum value among multiple first measurement results. In this scenario, the first beam may include a single beam. For instance, a second satellite network can generate a UL authorization associated with the reference signal of the highest intensity.

[0191] For example, the first measurement result corresponding to the first beam can be a specified number of larger measurement results among a plurality of first measurement results. That is, the number of first beams can be specified. For example, the first measurement result corresponding to the first beam can be the largest M values ​​among a plurality of first measurement results, where M is greater than 1. In this scenario, the first beam can include multiple beams. For example, the second satellite network can generate UL certification for a specified number of beams that have the best quality level (e.g., based on intensity) in the measured reference signal.

[0192] For example, the first measurement result corresponding to the first beam can be multiple measurement results greater than a first threshold. That is, the signal quality corresponding to the first beam can be specified. In this scenario, the first beam can include at least one beam. As another example, the second satellite network can generate a UL license for a reference signal at least greater than the RSRP threshold level. To ensure the first beam determined by the terminal device is compatible with the second satellite network, the second satellite network can send second information indicating the first beam to the terminal device through the first satellite network. If the second information indicates a single beam or multiple beams, the terminal device will monitor the PDCCH of the second satellite network based on the indicated beam, thereby improving the access success rate; otherwise, the terminal device will monitor the PDCCH based on the beam it has selected. For example, the terminal device directly suggests the selected first beam in the first information, and the second satellite network sends the PDCCH according to the first beam.

[0193] In some embodiments, the terminal device may receive the second information in the first switching command it receives.

[0194] In some embodiments, the terminal device may receive second information after sending first information. The second information is used to indicate the first beam. After receiving the first handover command, the terminal device can detect the downlink channel transmitted by the second satellite network based on the first beam indicated by the second information.

[0195] For example, the first beam can be indicated by an identifier of a reference signal associated with the first beam. For instance, the second satellite network can specify a reference signal associated with a UL license by associating an identifier (e.g., an index) of the reference signal with a UL license. Optionally, the second satellite network can include the identifier in a message (e.g., an RRC message) that provides the UL license to the terminal device.

[0196] Before the terminal device performs a satellite handover, the first information can be sent to the first satellite network at different times. In some embodiments, the first information can be sent to the first satellite network after the first satellite network makes a handover decision. For example, after the first satellite network determines the second satellite network through a handover decision, the terminal device can measure multiple beams of the second satellite network to generate the first information. For example, after determining the second satellite network, the first satellite network can send information about multiple beams in the second satellite network to the terminal device. After receiving this information, the terminal device performs beam measurement or beam selection to generate the transmitted first information. In some embodiments, the first information can be included in a first measurement report sent by the terminal device. For example, if the second satellite network does not require a decision from the first satellite network, or if the beam information of the second satellite network does not need to be communicated to the terminal device by the first satellite network, the terminal device can include the first information in the first measurement report used for handover.

[0197] In step S620, the first satellite network sends first information to the second satellite network. Since the terminal device has not yet connected to the second satellite network, the first information needs to be forwarded from the first satellite network to the second satellite network. Furthermore, the second information sent by the second satellite network to indicate the first beam also needs to be forwarded from the first satellite network to the terminal device.

[0198] In some embodiments, the first information may be included in a handover request sent by the first satellite network to the second satellite network to reduce interaction between the two satellite networks and save air interface resources.

[0199] In some embodiments, the second information may be included in the handover request confirmation sent by the second satellite network to the first satellite network, which can also reduce the interaction between the two satellite networks and save air interface resources.

[0200] See also Figure 6 In step S630, the first switching command is received.

[0201] The first handover command received by the terminal device comes from the first satellite network. That is, the first satellite network currently providing services to the terminal device instructs the terminal device to perform a handover. In some embodiments, the first network device corresponding to the first satellite network sends the first handover command to the terminal device.

[0202] The first handover command is used to trigger a handover by the terminal device. In some embodiments, the first satellite network can trigger a handover by sending RRC signaling to the terminal device. For example, the first satellite network can trigger a RACH-free handover by sending an RRC Reconfiguration message to the terminal device. In some embodiments, the first satellite network can complete the handover triggering through separately configured information. For example, messages related to the RACH-free handover command can be sent through additional proprietary signaling.

[0203] The first handover command instructs the terminal device to perform a satellite handover from the coverage area of ​​a first satellite network to the coverage area of ​​a second satellite network. In some embodiments, due to satellite movement, the area where the terminal device is located changes from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network, requiring a handover. In some embodiments, due to the movement of the terminal device or edge communication, the area where the terminal device is located changes from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network, requiring a handover.

[0204] The first handover command can be a satellite handover command in various forms. In some embodiments, the first handover command can be a command indicating that the terminal device cannot perform satellite handover via RACH. For example, the first handover command is a RACH-free handover command. Alternatively, the first handover command may not provide the terminal device with resources for random access. The embodiments of this application will be specifically described below using RACH-free handover as an example.

[0205] In some embodiments, the first satellite network may determine whether to send a RACH-free handover command to the terminal device based on actual circumstances. For example, when the terminal device's serving network needs to switch from the first satellite network to the second satellite network due to satellite movement or other reasons, a RACH-free handover may be preferred to reduce handover latency.

[0206] When a satellite handover is performed without RACH, the first satellite network needs to determine a second satellite network that meets the RACH-free handover conditions before sending the first handover command. As mentioned earlier, there are multiple satellite networks that can provide services to the terminal device; these satellite networks can be called candidate satellite networks. If no second satellite network meets the RACH-free handover conditions among the candidate satellite networks, the terminal device can perform a satellite handover following the traditional handover process. In other words, if the first satellite network does not find a second satellite network that meets the conditions, the first handover command is a command using the conventional handover method.

[0207] In some embodiments, the first satellite network may determine the second satellite network based on the measurement report of the terminal device. For example, the first satellite network may determine the second satellite network that meets certain conditions based on the measurement results in the measurement report. In some embodiments, the first satellite network may determine the second satellite network itself. For example, after determining multiple satellite networks that can provide services to the terminal device, the first satellite network may determine the second satellite network based on the location information or movement information of the terminal device.

[0208] In some embodiments, when a satellite handover is performed without RACH, the terminal device may send a first measurement report to a first satellite network. The first measurement report may include multiple second measurement results obtained by the terminal device from measuring reference signals of multiple candidate satellite networks, in order to determine a second satellite network among the multiple candidate satellite networks that meets the conditions for RACH-free handover.

[0209] As mentioned above, the reference signal for multiple candidate satellite networks can also be SSB-RS and / or CSI-RS. The signal quality of the reference signal can be at least one of RSRP, RSRQ, SINR, and RSSI.

[0210] For example, the terminal device can measure the signal power and / or signal quality of the reference signal in the coverage area of ​​each candidate satellite network. When there are multiple candidate satellite networks, multiple second measurement results can be obtained. These second measurement results can be used to generate a first measurement report. That is, if there are multiple target NTNs, such as NTN2, NTN3, etc., the terminal device reports reference signal measurement results based on multiple target NTNs.

[0211] For example, multiple second measurement results from a first measurement report can determine whether there is a second satellite network that meets the RACH-free handover condition. For instance, a second satellite network can be determined based on whether any one of multiple CSI-RS measurement results meets the RACH-free handover condition. Alternatively, it can be determined whether any SSB-RS measurement result from one or more candidate satellite networks meets the RACH-free handover condition.

[0212] In some embodiments, satellite handover can be satellite switching that supports no change to the PCI (no L3 mobility required). In scenarios where the PCI remains unchanged, the terminal device can switch to a target satellite with the same cell configuration except for satellite-specific information. For example, apart from TA acquisition and DL / UL synchronization in PCI-unchanged scenarios, the terminal device can maintain its terminal-specific configuration. That is, the terminal device does not need to perform reconfiguration. Therefore, the PCI-unchanged scenario is a specific case of handover between satellites with the same gateway / gNB.

[0213] Optionally, if the first satellite network receives RACH-free handover information from a candidate satellite network containing the same PCI, that candidate satellite network can be used as the preferred target satellite network.

[0214] In specific handover methods such as RACH-free handover, the quality of the reference signal from the second satellite network is crucial. For example, in RACH-free handover, to ensure reliable initial UL transmission, the downlink signal quality of the second satellite network needs to be greater than or equal to a certain threshold. Furthermore, RACH-free handover is only triggered when the downlink RSRP measured by the terminal equipment is greater than or equal to the RSRP threshold.

[0215] For example, the second measurement result corresponding to the second satellite network is the maximum value among multiple second measurement results. For instance, the first satellite network can select the satellite network with the largest RSRP from multiple candidate satellite networks as the second satellite network.

[0216] For example, the second measurement result corresponding to the second satellite network is one of a plurality of second measurement results that is greater than or equal to a second threshold. The second threshold can be set by the first satellite network. In some embodiments, the second threshold can be different for different signal quality parameters. In some embodiments, the second threshold can be determined based on parameters such as the actual communication environment and service type.

[0217] For example, if the first measurement report includes the RSRP of the SSB-RS of multiple candidate satellite networks, and the RSRP of a candidate satellite network is greater than or equal to the second threshold corresponding to the RSRP, then that candidate satellite network becomes the second satellite network. The first satellite network will, based on the measurement report from the terminal device, select no RACH handover as the optimal handover method and switch to that candidate satellite network.

[0218] For example, the terminal device reports a first measurement report to the first satellite network. After receiving the first measurement report, the first satellite network decides whether to trigger a RACH-free handover for the terminal device. The terminal device will only be triggered to perform a RACH-free handover if the downlink RSRP measured by the terminal device is greater than or equal to the RSRP threshold.

[0219] In some embodiments, the first satellite network sends a handover request to the second satellite network before sending a handover command, and sends the first handover command after receiving confirmation of the request from the second satellite network. For example, after determining that a satellite network meets the conditions and triggering a RACH-free handover, the first satellite network sends a RACH-free handover request to the second satellite network. The second satellite network may send a handover request confirmation (ACK) message to the first satellite network. Based on this, the first satellite network may send the first handover command to the terminal device.

[0220] For example, a handover request acknowledgment can also be called a handover request response, an answer message, etc. A handover request acknowledgment can be represented as HANDOVER REQUEST ACKNOWLEDGE.

[0221] The handover request confirmation sent by the second satellite network may include various information to enable the first satellite network to inform the terminal device via the first handover command. For example, the handover request confirmation may include the UL authorization determined by the second satellite network. Alternatively, the handover request confirmation may also include the SSB index and pre-assigned authorization related to the terminal device sent by the second satellite network.

[0222] In some embodiments, the handover request confirmation may include information related to resource reservation, or power-related factor information when the terminal device switches access to the second satellite network. The power-related information has been combined... Figure 4 Please provide an explanation.

[0223] For example, the handover request confirmation includes the second information described above to reduce interaction between the terminal device, the first satellite network, and the second satellite network. That is, the second satellite network can indicate the first beam or SSB index associated with the first resource through the handover request confirmation.

[0224] The first satellite network can generate a first handover command based on the handover request from the second satellite network. The first handover command may include various types of information.

[0225] In some embodiments, the first handover command includes one or more of the following information: a pre-allocated authorization from the second satellite network; a first resource pre-configured by the second satellite network; a beam index associated with a synchronization signal block in the second satellite network; the maximum signal quality reported within the coverage area received by the second satellite network and its associated beam index; a beam index associated with a specified signal quality reported within the coverage area received by the second satellite network; the average admission power of terminal devices other than the terminal device in the second satellite network; and the maximum admission power of terminal devices other than the terminal device in the second satellite network.

[0226] For example, the authorization and pre-configured first resources pre-allocated by the second satellite network are used by the terminal device for handover.

[0227] For example, the beam index associated with the synchronization signal block in the second satellite network refers to the beam index corresponding to the SSB associated with the pre-allocated authorization or the first resource in the second satellite network.

[0228] For example, the maximum signal quality reported within the coverage area and its associated beam index can be the beam index corresponding to the signal with the highest signal quality received in the second satellite network, so that the terminal device can determine the access beam.

[0229] Optionally, the terminal device can select the highest signal quality and associated beam from the signal quality reported by other terminal devices within the coverage area of ​​the second satellite network as its access beam for accessing the second satellite network.

[0230] For example, the beam index associated with a specified signal quality reported within the coverage area can be the beam index of the signal corresponding to the specified signal quality parameter, which can be used by the terminal device to determine the optimal access beam.

[0231] Optionally, the specified signal quality can be determined based on the average signal quality and a specific reference value. For example, the specified signal quality can be the signal quality obtained by adding or subtracting the average signal quality from the specific reference value.

[0232] Optionally, the specified signal quality can be determined based on the maximum signal quality and a specific reference value. For example, the specified signal quality can be the signal quality obtained by subtracting the maximum signal quality from the specific reference value.

[0233] Optionally, the beam associated with the reported average signal quality plus or minus a specific reference amount is used as its access beam in the second satellite network.

[0234] Alternatively, signal quality can also be referred to as signal strength. Signal quality can be represented by at least one parameter that indicates signal quality, such as RSRP, RSRQ, RSSI, or others mentioned above.

[0235] For example, the average and maximum values ​​of the admission power of terminal devices other than the terminal devices in the second satellite network can be used by the terminal devices to determine the transmission power.

[0236] For example, when the first handover command is a no-RACH handover command, the command may include one or more of the following information: pre-allocated authorization, beam index associated with SSB access, and resource reservation; azimuth angle of the second satellite network relative to the terminal device based on the terminal device location information; maximum signal strength received by the second satellite network within its coverage area, such as RSRP and RSSI; average signal strength received by the second satellite network within its coverage area, such as RSRP and RSSI; average access received power of other terminal devices admitted to the second satellite network; maximum access received power of other terminal devices admitted to the second satellite network; and time-related parameters of the second satellite network.

[0237] Depend on Figure 6 It is understood that in certain handovers (e.g., handovers without RACH), the terminal device can send information to the second satellite network after determining the second satellite network to be handed over, specifying the first beam, so that the second satellite network can make more effective resource reservations, thereby improving the success rate of the handover. When resource reservation is indicated by UL authorization, UL authorization can be allocated through RRC signaling and / or the PDCCH of the second satellite network for the terminal device to receive.

[0238] To facilitate understanding, the following will be combined with... Figure 7 and Figure 8 The two possible implementations shown are illustrated by example. Figure 7 It is a schematic flowchart of a terminal device sending first information to a second satellite network before receiving the first handover command. Figure 8 This is a schematic flowchart illustrating the RACH-free handover process for terminal devices.

[0239] See Figure 7 In step S710, the terminal device sends a first measurement report to the first satellite network.

[0240] In step S720, the first satellite network makes a handover decision to determine the second satellite network.

[0241] In step S730, the terminal device sends first information to the first satellite network. The terminal device can identify and measure the beam identification information of the second satellite network sent by the first satellite network, and generate and send the first information.

[0242] In step S740, the first satellite network sends a handover request to the second satellite network. The handover request contains first information for the second satellite network to determine the first beam.

[0243] In step S750, the second satellite network sends a handover request confirmation to the first satellite network. The handover request confirmation includes second information used to indicate the first beam to the terminal device.

[0244] In step S760, the first satellite network sends a first handover command to the terminal device.

[0245] In step S770, the terminal device sends an initial uplink transmission to the second satellite network.

[0246] Figure 7 The first information sent by the terminal device occurs after the handover decision. For example, before the terminal device sends the first information for the second satellite network to determine the first beam, the first satellite network may send the decision result of step S504 to the terminal device so that the terminal device can determine the second satellite network.

[0247] See Figure 8 In step S810, the terminal device sends a measurement control and report to the first satellite network.

[0248] In step S820, the first satellite network makes a handover decision (HO decision).

[0249] In step S830, the first satellite network sends a handover request (HO request) to the second satellite network.

[0250] In step S840, the second satellite network sends a handover request acknowledgment (HO requestACK) to the first satellite network.

[0251] In step S850, the first satellite network sends RACH-lessHO configuration information to the terminal device. The terminal device will then start timers T304 and T430 sequentially.

[0252] In step S860, the terminal device sends an initial uplink transmission. This initial uplink transmission is sent using available uplink grants (RRC, MAC, PHY). The initial uplink transmission includes the transmission of an RRCReconfigurationComplete message.

[0253] In step S870, the terminal device receives an acknowledgment (RACH-less HO ACK) from the second satellite network, thus completing the RACH-less handover. The second satellite network releases the pre-allocated UL authorization. The terminal device stops timer T304.

[0254] Figure 8 The handover request confirmation will include the second information mentioned above, so that the terminal device can determine the first beam or SSB associated with the reserved resources of the second satellite network.

[0255] In certain mobility scenarios, a terminal device can receive a list of candidate satellite networks (which may be simply referred to as candidate networks) and a handover command with handover conditions, and autonomously execute a handover (or handover attempt) to a target satellite network. The target satellite network is one of the candidate networks that meets the handover conditions. This handover can be called a "conditional handover (CHO)," and the handover command associated with a conditional handover can be called a "conditional handover command." For conditional handovers, the terminal device can autonomously select a target network from the candidate networks based on measurements of the candidate networks.

[0256] In NTN, if a CHO is configured, the condition for a terminal device to perform satellite handover can be called the first condition. That is, satellite handover is performed only if the first condition is met.

[0257] If RACH-free handover and CHO are configured, the first handover command needs to specify multiple candidate satellite networks and multiple uplink grants. For example, the first handover command includes parameters for multiple candidate satellite networks, and the first resource in the first handover command includes multiple uplink grants. The terminal device can determine a second satellite network from among the multiple candidate satellite networks and determine the uplink grant for satellite handover from among the multiple uplink grants, provided that the first condition is met.

[0258] For example, in configuring satellite handover without RACH and CHO, the first and second satellite networks need to indicate timing adjustments and optional multiple pre-assigned authorizations.

[0259] For example, the first satellite network may also receive third information sent by the terminal device. The third information is used to indicate the first condition. The third information may include one or more of the following: handover conditions based on the association of an SSB-RS with at least one candidate satellite network; handover conditions based on the association of a CSI-RS with at least one candidate satellite network; measurement results / measurement information of at least one SSB-RS or CSI-RS; at least one SSB-RS or CSI-RS associated with a contention-free random access resource.

[0260] For example, the first satellite network can receive RRC reconfiguration information from the terminal equipment. This RRC reconfiguration information may include signal measurement results from at least one target satellite network, as well as at least one SSB-RS, at least one CSI-RS, SSB-based CHO execution conditions, and CSI-RS-based CHO execution conditions associated with the execution of CHO.

[0261] The above text introduces the handover conditions of no RACH handover and CHO in NTN, so that terminal equipment can autonomously perform satellite handover when the conditions are met.

[0262] The above text combined Figures 1 to 8 The method embodiments of this application are described in detail below. Figures 9 to 15 The present application provides a detailed description of the apparatus embodiments. It should be understood that the descriptions of the apparatus embodiments correspond to the descriptions of the method embodiments; therefore, any parts not described in detail can be found in the foregoing method embodiments.

[0263] Figure 9 This is a schematic block diagram of a terminal device according to an embodiment of this application. The terminal device 900 can be any of the terminal devices described above. Figure 9 The terminal device 900 shown includes a transmitting unit 910 and a first receiving unit 920.

[0264] The transmitting unit 910 can be used to transmit first information, which is used by the second satellite network to determine a first beam corresponding to the terminal device. The first beam includes one or more beams. The first beam is related to a first resource and / or a second resource pre-configured by the second satellite network for satellite handover.

[0265] The first receiving unit 920 can be used to receive a first handover command, which instructs the terminal device to perform a satellite handover from the first satellite network coverage area to the second satellite network coverage area.

[0266] Optionally, the first handover command includes one or more of the following information: a pre-allocated authorization for the second satellite network; a first resource pre-configured for the second satellite network; a beam index associated with a synchronization signal block in the second satellite network; the maximum signal quality received by the second satellite network within its coverage area; the average signal quality received by the second satellite network within its coverage area; the average admission power of terminal devices other than the terminal device in the second satellite network; and the maximum admission power of terminal devices other than the terminal device in the second satellite network.

[0267] Optionally, the first information includes multiple first measurement results obtained by the terminal device from measuring reference signals of multiple beams of the second satellite network, and the multiple first measurement results are used to determine the first beam.

[0268] Optionally, the first measurement result corresponding to the first beam is the maximum value among multiple first measurement results, or the M largest values ​​among the multiple first measurement results.

[0269] Optionally, the first measurement result corresponding to the first beam is greater than the first threshold.

[0270] Optionally, the first resource is a reserved resource for satellite handover, and the second resource is a scheduled uplink resource used by the terminal equipment to perform satellite handover.

[0271] Optionally, the first receiving unit 920 is further configured to receive second information after sending the first information, the second information being used to indicate the first beam; the terminal device 900 also includes a second receiving unit, which can be used to detect the downlink channel sent by the second satellite network according to the first beam after receiving the first handover command.

[0272] Optionally, the first beam is indicated by an identifier of a reference signal associated with the first beam.

[0273] Optionally, the satellite handover is a RACH-free handover, and the second satellite network is a satellite network that meets the RACH-free handover conditions. The transmitting unit 910 is further configured to transmit a first measurement report before transmitting the first information. The first measurement report is used by the first satellite network to determine the second satellite network among multiple candidate satellite networks. The first measurement report includes multiple second measurement results of the terminal device measuring the reference signals of the multiple candidate satellite networks.

[0274] Optionally, the second measurement result corresponding to the second satellite network is the maximum value among multiple second measurement results, or it is a second measurement result that is greater than or equal to a second threshold among multiple second measurement results.

[0275] Optionally, the reference signal includes SSB-RS and / or CSI-RS.

[0276] Optionally, the first beam is also used to carry one or more synchronization signal blocks for satellite switching by the terminal equipment, and the index of the one or more synchronization signal blocks is associated with the first resource.

[0277] Optionally, the first switching command is a no-RACH switching command.

[0278] Optionally, satellite handover is performed if a first condition is met. The first handover command includes parameters of multiple candidate satellite networks, the first resource includes multiple uplink grants, and the terminal device 900 further includes a first determining unit, which can be used to determine a second satellite network among multiple candidate satellite networks; and a second determining unit, which can be used to determine an uplink grant for the terminal device to perform handover among multiple uplink grants.

[0279] Optionally, the transmitting unit 910 is further configured to transmit third information to the first satellite network, the third information being used to indicate the first condition; wherein the third information includes one or more of the following: handover conditions based on the association of the SSB-RS with at least one candidate satellite network; handover conditions based on the association of the CSI-RS with at least one candidate satellite network; measurement results / measurement information of at least one SSB-RS or CSI-RS; at least one SSB-RS or CSI-RS associated with a contention-free random access resource.

[0280] Figure 10 This is a schematic block diagram of a network device according to an embodiment of this application. The network device 1000 can be any type of network device corresponding to the first satellite network described above. Figure 10 The network device 1000 shown includes a receiving unit 1010, a first transmitting unit 1020, and a second transmitting unit 1030.

[0281] The receiving unit 1010 can be used to receive the first information sent by the terminal device.

[0282] The first transmitting unit 1020 can be used to transmit first information to the second satellite network. The first information is used by the second satellite network to determine a first beam corresponding to the terminal device. The first beam includes one or more beams. The first beam is related to a first resource and / or a second resource pre-configured by the second satellite network for satellite handover.

[0283] The second sending unit 1030 can be used to send a first handover command to the terminal device. The first handover command is used to instruct the terminal device to perform a satellite handover from the first satellite network coverage area to the second satellite network coverage area.

[0284] Optionally, the first handover command includes one or more of the following information: a pre-allocated authorization for the second satellite network; a first resource pre-configured for the second satellite network; a beam index associated with a synchronization signal block in the second satellite network; the maximum signal quality received by the second satellite network within its coverage area; the average signal quality received by the second satellite network within its coverage area; the average admission power of terminal devices other than the terminal device in the second satellite network; and the maximum admission power of terminal devices other than the terminal device in the second satellite network.

[0285] Optionally, the first resource is a reserved resource for satellite handover, and the second resource is a scheduled uplink resource used by the terminal equipment to perform satellite handover.

[0286] Optionally, the receiving unit 1010 is further configured to receive second information sent by the second satellite network after sending the first information to the second satellite network, and the first sending unit 1020 is further configured to send the second information to the terminal device, the second information being used to indicate the first beam.

[0287] Optionally, the satellite handover is a RACH-free handover, and the second satellite network is a satellite network that meets the RACH-free handover conditions. The receiving unit 1010 is further configured to receive a first measurement report sent by the terminal device before receiving the first information sent by the terminal device. The first measurement report is used by the first satellite network to determine the second satellite network among multiple candidate satellite networks. The first measurement report includes multiple second measurement results of the terminal device measuring the reference signals of the multiple candidate satellite networks.

[0288] Optionally, the second measurement result corresponding to the second satellite network is the maximum value among multiple second measurement results, or it is a second measurement result that is greater than or equal to a second threshold among multiple second measurement results.

[0289] Optionally, the reference signal includes SSB-RS and / or CSI-RS.

[0290] Optionally, the first switching command is a no-RACH switching command.

[0291] Optionally, satellite handover is performed when a first condition is met. The first handover command includes parameters of multiple candidate satellite networks. The receiving unit 1010 is further configured to receive third information sent by the terminal device. The third information is used to indicate the first condition. The third information includes one or more of the following: handover conditions based on the association of SSB-RS with at least one candidate satellite network; handover conditions based on the association of CSI-RS with at least one candidate satellite network; measurement results / measurement information of at least one SSB-RS or CSI-RS; and at least one SSB-RS or CSI-RS associated with a contention-free random access resource.

[0292] Figure 11 This is a schematic block diagram of another network device according to an embodiment of this application. The network device 1100 can be any type of network device corresponding to the second satellite network described above. Figure 11 The network device 1100 shown includes a receiving unit 1110 and a first transmitting unit 1120.

[0293] The receiving unit 1110 can be used to receive first information sent by the first satellite network. The first information is used to determine the first beam corresponding to the second satellite network and the terminal device. The first beam includes one or more beams. The first beam is related to the first and / or second resources pre-configured by the second satellite network for satellite handover.

[0294] The first transmitting unit 1120 can be used to send a handover request confirmation to the first satellite network according to the handover request sent by the first satellite network. The handover request confirmation is used by the first satellite network to send a first handover command to the terminal device. The first handover command is used to instruct the terminal device to perform a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network.

[0295] Optionally, the first handover command includes one or more of the following information: a pre-allocated authorization for the second satellite network; a first resource pre-configured for the second satellite network; a beam index associated with a synchronization signal block in the second satellite network; the maximum signal quality received by the second satellite network within its coverage area; the average signal quality received by the second satellite network within its coverage area; the average admission power of terminal devices other than the terminal device in the second satellite network; and the maximum admission power of terminal devices other than the terminal device in the second satellite network.

[0296] Optionally, the first information includes multiple first measurement results obtained by the terminal device from measuring reference signals of multiple beams of the second satellite network, and the multiple first measurement results are used to determine the first beam.

[0297] Optionally, the first measurement result corresponding to the first beam is the maximum value among multiple first measurement results, or the M largest values ​​among the multiple first measurement results.

[0298] Optionally, the first measurement result corresponding to the first beam is greater than the first threshold.

[0299] Optionally, the first resource is a reserved resource for satellite handover, and the second resource is a scheduled uplink resource used by the terminal equipment to perform satellite handover.

[0300] Optionally, after receiving the first information, the first transmitting unit 1120 is further configured to transmit second information to the first satellite network, the second information being used to indicate the first beam; the network device 1100 also includes a second transmitting unit, which can be used to transmit a downlink channel according to the first beam after sending a handover request confirmation to the first satellite network.

[0301] Optionally, the first beam is indicated by an identifier of a reference signal associated with the first beam.

[0302] Optionally, the reference signal includes SSB-RS and / or CSI-RS.

[0303] Optionally, the first beam is also used to carry one or more synchronization signal blocks for satellite switching by the terminal equipment, and the index of the one or more synchronization signal blocks is associated with the first resource.

[0304] Optionally, the first switching command is a no-RACH switching command.

[0305] Figure 12 This is a schematic block diagram of another terminal device according to an embodiment of this application. The terminal device 1200 can be any of the terminal devices described above. Figure 12 The terminal device 1200 shown includes a receiving unit 1210 and a determining unit 1220.

[0306] The receiving unit 1210 can be used to receive a first handover command, which instructs the terminal device to perform a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network. The first handover command includes power-related information within the coverage area of ​​the second satellite network and / or the relative position information of the second satellite corresponding to the second satellite network and the terminal device.

[0307] The determining unit 1220 can be used to determine the first power for uplink transmission to the second satellite network according to the first switching command.

[0308] Optionally, the power-related information within the coverage area of ​​the second satellite network includes one or more of the following parameters: the average signal quality of some or all uplink beams accessing the area; the maximum signal quality of some or all uplink beams accessing the area; the transmit power of at least some of the terminal devices already accessed in the area transmitting random access uplink channels; the average admission power of terminal devices other than the terminal devices in the second satellite network; the maximum admission power of terminal devices other than the terminal devices in the second satellite network; the average path loss within the coverage area of ​​the second satellite network; and the maximum path loss within the coverage area of ​​the second satellite network.

[0309] Optionally, the first power is determined based on power-related information and the maximum output power of the terminal device.

[0310] Optionally, signal quality is one or more of the following parameters: RSRP, RSRQ, RSSI.

[0311] Optionally, the transmit power of at least some of the terminal devices already connected in the area for transmitting the random access uplink channel includes one or more of the following: the transmit power of at least some of the terminal devices for transmitting message A; the transmit power of at least some of the terminal devices for transmitting message 3.

[0312] Optionally, the relative position information is used to determine the path loss compensation factor of the terminal device in the second satellite network. The relative position information includes one or more of the following: the distance between the terminal device and the second satellite; the azimuth angle between the terminal device and the second satellite.

[0313] Optionally, the path loss compensation factor is determined based on the azimuth angle between the terminal equipment and the second satellite, and the path loss compensation factor K is determined according to the following formula:

[0314]

[0315] Wherein, δ1 represents the azimuth angle between the terminal device and the first satellite corresponding to the first satellite network, and δ2 represents the azimuth angle between the terminal device and the second satellite.

[0316] Optionally, the terminal device performs uplink transmission with a first power P on the uplink bandwidth b of the carrier f in the serving cell c. PUSCH,b,f,c Determined according to the following formula:

[0317]

[0318] Where i represents the transmission timing, j represents the index of the parameter set configuration, and q d The index represents the reference signal, l represents the index of the power control adjustment state, μ is related to the subcarrier spacing, and P CMAX,f,c (i) represents the maximum output power of the terminal device in the second satellite network. This indicates the current transmit power of the terminal device within the first satellite network. Indicates uplink resource bandwidth, α b,f,c (j) represents the path loss compensation factor of the terminal device within the first satellite network, PL b,f,c (q d ) represents the downlink path loss, Δ TF,b,c,f (i) represents the power adjustment amount, f b,f,c (i,l) represents the power control adjustment state.

[0319] Optionally, the first handover command is a RACH-free handover command, and the power adjustment amount in the first power is determined based on the RACH-free power adjustment counter. The value of the power adjustment counter is related to the parameters of the terminal device accessing the first satellite network.

[0320] Optionally, the value of the power adjustment counter is the number of times the terminal device establishes a connection with the first satellite network.

[0321] Optionally, the power adjustment amount is also determined based on the power adjustment factor, which is determined based on the service type of the terminal equipment.

[0322] Optionally, the terminal device performs uplink transmission with a first power P on the uplink bandwidth b of the carrier f in the serving cell c. PUSCH,b,f,c Determined according to the following formula:

[0323]

[0324] Where N represents the power adjustment factor, and N > 1.

[0325] Optionally, the terminal device performs uplink transmission with a first power P on the uplink bandwidth b of the carrier f in the serving cell c. PUSCH,b,f,c Determined according to the following formula:

[0326]

[0327] Where K represents the path loss compensation factor and N represents the power adjustment factor.

[0328] Figure 13 This is a schematic block diagram of another network device according to an embodiment of this application. The network device 1300 can be any type of network device corresponding to the first satellite network described above. Figure 13 The network device 1300 shown includes a determining unit 1310 and a sending unit 1310.

[0329] The determining unit 1310 can be used to confirm and determine a first handover command based on a handover request sent by the second satellite network. The first handover command is used to instruct the terminal device to perform a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network. The first handover command includes power-related information within the coverage area of ​​the second satellite network and / or the relative position information between the second satellite corresponding to the second satellite network and the terminal device.

[0330] The transmitting unit 1320 can be used to send a first handover command to the terminal device. The first handover command is used by the terminal device to determine the first power for uplink transmission to the second satellite network.

[0331] Optionally, the power-related information within the coverage area of ​​the second satellite network includes one or more of the following parameters: the average signal quality of some or all uplink beams accessing the area; the maximum signal quality of some or all uplink beams accessing the area; the transmit power of at least some of the terminal devices already accessed in the area transmitting random access uplink channels; the average admission power of terminal devices other than the terminal devices in the second satellite network; the maximum admission power of terminal devices other than the terminal devices in the second satellite network; the average path loss within the coverage area of ​​the second satellite network; and the maximum path loss within the coverage area of ​​the second satellite network.

[0332] Optionally, the first power is determined based on power-related information and the maximum output power of the terminal device.

[0333] Optionally, signal quality is one or more of the following parameters: RSRP, RSRQ, RSSI.

[0334] Optionally, the transmit power of at least some of the terminal devices already connected in the area for transmitting the random access uplink channel includes one or more of the following: the transmit power of at least some of the terminal devices for transmitting message A; the transmit power of at least some of the terminal devices for transmitting message 3.

[0335] Optionally, the relative position information is used to determine the path loss compensation factor of the terminal device in the second satellite network. The relative position information includes one or more of the following: the distance between the terminal device and the second satellite; the azimuth angle between the terminal device and the second satellite.

[0336] Optionally, the path loss compensation factor is determined based on the azimuth angle between the terminal equipment and the second satellite, and the path loss compensation factor K is determined according to the following formula:

[0337]

[0338] Wherein, δ1 represents the azimuth angle between the terminal device and the first satellite corresponding to the first satellite network, and δ2 represents the azimuth angle between the terminal device and the second satellite.

[0339] Optionally, the terminal device performs uplink transmission with a first power P on the uplink bandwidth b of the carrier f in the serving cell c. PUSCH,b,f,c Determined according to the following formula:

[0340]

[0341] Where i represents the transmission timing, j represents the index of the parameter set configuration, and q d The index represents the reference signal, l represents the index of the power control adjustment state, μ is related to the subcarrier spacing, and P CMAX,f,c(i) represents the maximum output power of the terminal device in the second satellite network. This indicates the current transmit power of the terminal device within the first satellite network. Indicates uplink resource bandwidth, α b,f,c (j) represents the path loss compensation factor of the terminal device within the first satellite network, PL b,f,c (q d ) represents the downlink path loss, Δ TF,b,c,f (i) represents the power adjustment amount, f b,f,c (i,l) represents the power control adjustment state.

[0342] Optionally, the first handover command is a RACH-free handover command, and the power adjustment amount in the first power is determined based on the RACH-free power adjustment counter. The value of the power adjustment counter is related to the parameters of the terminal device accessing the first satellite network.

[0343] Optionally, the value of the power adjustment counter is the number of times the terminal device establishes a connection with the first satellite network.

[0344] Optionally, the power adjustment amount is also determined based on the power adjustment factor, which is determined based on the service type of the terminal equipment.

[0345] Optionally, the terminal device performs uplink transmission with a first power P on the uplink bandwidth b of the carrier f in the serving cell c. PUSCH,b,f,c Determined according to the following formula:

[0346]

[0347] Where N represents the power adjustment factor, and N > 1.

[0348] Optionally, the terminal device performs uplink transmission with a first power P on the uplink bandwidth b of the carrier f in the serving cell c. PUSCH,b,f,c Determined according to the following formula:

[0349]

[0350] Where K represents the path loss compensation factor and N represents the power adjustment factor.

[0351] Figure 14 This is a schematic block diagram of another network device according to an embodiment of this application. The network device 1400 can be any type of network device corresponding to the second satellite network described above. Figure 14 The network device 1400 shown includes a transmitting unit 1410.

[0352] The sending unit 1410 can be used to send a handover request confirmation to the first satellite network. The handover request confirmation is used by the first satellite network to determine a first handover command. The first handover command is used to instruct the terminal device to perform a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network.

[0353] The first handover command includes power-related information within the coverage area of ​​the second satellite network, and / or the relative position information between the second satellite corresponding to the second satellite network and the terminal device. The first handover command is used by the terminal device to determine the first power for uplink transmission to the second satellite network.

[0354] Optionally, the power-related information within the coverage area of ​​the second satellite network includes one or more of the following parameters: the average signal quality of some or all uplink beams accessing the area; the maximum signal quality of some or all uplink beams accessing the area; the transmit power of at least some of the terminal devices already accessed in the area transmitting random access uplink channels; the average admission power of terminal devices other than the terminal devices in the second satellite network; the maximum admission power of terminal devices other than the terminal devices in the second satellite network; the average path loss within the coverage area of ​​the second satellite network; and the maximum path loss within the coverage area of ​​the second satellite network.

[0355] Optionally, the first power is determined based on power-related information and the maximum output power of the terminal device. Optionally, the signal quality is one or more of the following parameters: RSRP, RSRQ, RSSI.

[0356] Optionally, the transmit power of at least some of the terminal devices already connected in the area for transmitting the random access uplink channel includes one or more of the following: the transmit power of at least some of the terminal devices for transmitting message A; the transmit power of at least some of the terminal devices for transmitting message 3.

[0357] Optionally, the relative position information is used to determine the path loss compensation factor of the terminal device in the second satellite network. The relative position information includes one or more of the following: the distance between the terminal device and the second satellite; the azimuth angle between the terminal device and the second satellite.

[0358] Optionally, the path loss compensation factor is determined based on the azimuth angle between the terminal equipment and the second satellite, and the path loss compensation factor K is determined according to the following formula:

[0359]

[0360] Wherein, δ1 represents the azimuth angle between the terminal device and the first satellite corresponding to the first satellite network, and δ2 represents the azimuth angle between the terminal device and the second satellite.

[0361] Optionally, the terminal device performs uplink transmission with a first power P on the uplink bandwidth b of the carrier f in the serving cell c. PUSCH,b,f,c Determined according to the following formula:

[0362]

[0363] Where i represents the transmission timing, j represents the index of the parameter set configuration, and q d The index represents the reference signal, l represents the index of the power control adjustment state, μ is related to the subcarrier spacing, and P CMAX,f,c (i) represents the maximum output power of the terminal device in the second satellite network. This indicates the current transmit power of the terminal device within the first satellite network. Indicates uplink resource bandwidth, α b,f,c (j) represents the path loss compensation factor of the terminal device within the first satellite network, PL b,f,c (q d ) represents the downlink path loss, Δ TF,b,c,f (i) represents the power adjustment amount, f b,f,c (i,l) represents the power control adjustment state.

[0364] Optionally, the first handover command is a RACH-free handover command, and the power adjustment amount in the first power is determined based on the RACH-free power adjustment counter. The value of the power adjustment counter is related to the parameters of the terminal device accessing the first satellite network.

[0365] Optionally, the value of the power adjustment counter is the number of times the terminal device establishes a connection with the first satellite network.

[0366] Optionally, the power adjustment amount is also determined based on the power adjustment factor, which is determined based on the service type of the terminal equipment.

[0367] Optionally, the terminal device performs uplink transmission with a first power P on the uplink bandwidth b of the carrier f in the serving cell c. PUSCH,b,f,c Determined according to the following formula:

[0368]

[0369] Where N represents the power adjustment factor, and N > 1.

[0370] Optionally, the terminal device performs uplink transmission with a first power P on the uplink bandwidth b of the carrier f in the serving cell c. PUSCH,b,f,c Determined according to the following formula:

[0371]

[0372] Where K represents the path loss compensation factor and N represents the power adjustment factor.

[0373] Figure 15 The diagram shown is a schematic structural diagram of a communication device according to an embodiment of this application. Figure 15 The dashed lines indicate that the unit or module is optional. The device 1500 can be used to implement the methods described in the above method embodiments. The device 1500 can be a chip, a terminal device, or a network device.

[0374] Apparatus 1500 may include one or more processors 1510. The processor 1510 may support apparatus 1500 in implementing the methods described in the preceding method embodiments. The processor 1510 may be a general-purpose processor or a special-purpose processor. For example, the processor may be a central processing unit (CPU). Alternatively, the processor may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0375] The apparatus 1500 may further include one or more memories 1520. The memories 1520 store a program that can be executed by the processor 1510, causing the processor 1510 to perform the methods described in the preceding method embodiments. The memories 1520 may be independent of the processor 1510 or integrated into the processor 1510.

[0376] The device 1500 may also include a transceiver 1530. The processor 1510 can communicate with other devices or chips via the transceiver 1530. For example, the processor 1510 can send and receive data with other devices or chips via the transceiver 1530.

[0377] This application also provides a computer-readable storage medium for storing a program. This computer-readable storage medium can be applied to a terminal device or network device provided in this application embodiment, and the program causes a computer to execute the methods performed by the terminal device or network device in the various embodiments of this application.

[0378] The computer-readable storage medium can be any available medium that a computer can read, or a data storage device such as a server or data center that integrates one or more available media. The available medium can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital video discs, DVDs), or semiconductor media (e.g., solid-state disks, SSDs), etc.

[0379] This application also provides a computer program product. The computer program product includes a program. This computer program product can be applied to a terminal device or network device provided in this application embodiment, and the program causes a computer to execute the methods performed by the terminal or network device in various embodiments of this application.

[0380] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0381] This application also provides a computer program. This computer program can be applied to a terminal device or network device provided in this application, and the computer program causes the computer to execute the methods performed by the terminal or network device in various embodiments of this application.

[0382] In this application, the terms "system" and "network" are used interchangeably. Furthermore, the terminology used in this application is only for explaining specific embodiments of the application and is not intended to limit the application. The terms "first," "second," "third," and "fourth," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. In addition, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0383] In the embodiments of this application, the term "instruction" can be a direct instruction, an indirect instruction, or an indication of a relationship. For example, A instructing B can mean that A directly instructs B, such as B being able to obtain information through A; it can also mean that A indirectly instructs B, such as A instructing C, so B can obtain information through C; or it can mean that there is a relationship between A and B.

[0384] In the embodiments of this application, the term "correspondence" may indicate a direct or indirect correspondence between two things, or an association between two things, or a relationship such as instruction and being instructed, configuration and being configured.

[0385] In the embodiments of this application, "predefined" or "preconfigured" can be implemented by pre-storing corresponding codes, tables, or other means that can be used to indicate relevant information in the device (e.g., including terminal devices and network devices). This application does not limit the specific implementation method. For example, predefined can refer to what is defined in the protocol.

[0386] In the embodiments of this application, the term "protocol" may refer to standard protocols in the field of communications, such as LTE protocols, NR protocols, and related protocols applied in future communication systems. This application does not limit the scope of these protocols.

[0387] In the embodiments of this application, determining B based on A does not mean determining B solely based on A; B can also be determined based on A and / or other information.

[0388] In the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0389] In the embodiments of this application, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0390] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0391] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0392] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0393] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for satellite handover in non-terrestrial networks, characterized in that, The method, applied to satellite handover from a first satellite network coverage area to a second satellite network coverage area, includes: Receive a first handover command, the first handover command including power-related information within the coverage area of ​​the second satellite network, or the first handover command including power-related information within the coverage area of ​​the second satellite network and the relative position information of the second satellite and the terminal device corresponding to the second satellite network; Based on the first switching command, a first power for uplink transmission to the second satellite network is determined; The power-related information includes the transmit power of at least some of the terminal devices that have been connected within the coverage area of ​​the second satellite network when sending random access uplink channels.

2. The method according to claim 1, characterized in that, The power-related information within the coverage area of ​​the second satellite network also includes one or more of the following parameters: The average signal quality of some or all uplink beams accessed within the area; The maximum signal quality of some or all uplink beams accessed within the area; The average access power of terminal devices other than the terminal device in the second satellite network; The maximum access power of terminal devices other than the aforementioned terminal device in the second satellite network; Average path loss within the coverage area of ​​the second satellite network; The maximum path loss within the coverage area of ​​the second satellite network.

3. The method according to claim 2, characterized in that, The first power is determined based on the power-related information and the maximum output power of the terminal device.

4. The method according to claim 2, characterized in that, The signal quality is one or more of the following parameters: Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), and Reference Signal Strength Indication (RSSI).

5. The method according to claim 2, characterized in that, The transmit power of at least some of the terminal devices already connected within the area that transmit through the random access channel includes one or more of the following: The transmission power of at least some of the terminal devices transmitting message A; The transmission power of at least some of the terminal devices sending message 3.

6. The method according to any one of claims 1-5, characterized in that, The relative position information is used to determine the path loss compensation factor of the terminal device in the second satellite network, and the relative position information includes one or more of the following: The distance between the terminal device and the second satellite; The azimuth angle between the terminal device and the second satellite.

7. The method according to claim 6, characterized in that, The path loss compensation factor is determined based on the azimuth angle between the terminal device and the second satellite, and the path loss compensation factor K is determined according to the following formula: ； Wherein, δ1 represents the azimuth angle between the terminal device and the first satellite corresponding to the first satellite network, and δ2 represents the azimuth angle between the terminal device and the second satellite.

8. The method according to claim 7, characterized in that, The terminal device performs uplink transmission with a first power P on the uplink bandwidth b of carrier f in serving cell c. PUSCH,b,f,c Determined according to the following formula: ； Where i represents the transmission timing, j represents the index of the parameter set configuration, and q d The index represents the reference signal, l represents the index of the power control adjustment state, and μ is related to the subcarrier spacing. This indicates the maximum output power of the terminal device in the second satellite network. This indicates the current transmission power of the terminal device within the first satellite network. Indicates uplink bandwidth. This represents the path loss compensation factor for the terminal device within the first satellite network. Indicates downlink path loss. Indicates the amount of power adjustment. This indicates the power control adjustment status.

9. The method according to any one of claims 1-5, characterized in that, The first handover command is a RACH-free handover command, and the power adjustment amount in the first power is determined based on the RACH-free power adjustment counter. The value of the power adjustment counter is related to the parameters of the terminal device accessing the first satellite network.

10. The method according to claim 9, characterized in that, The value of the power adjustment counter is the number of times the terminal device has established a connection with the first satellite network.

11. The method according to claim 9, characterized in that, The power adjustment amount is also determined based on a power adjustment factor, which is determined based on the service type of the terminal device.

12. The method according to claim 11, characterized in that, The terminal device performs uplink transmission with a first power P on the uplink bandwidth b of carrier f in serving cell c. PUSCH,b,f,c Determined according to the following formula: ； Where i represents the transmission timing, j represents the index of the parameter set configuration, and q d The index represents the reference signal, l represents the index of the power control adjustment state, and μ is related to the subcarrier spacing. This indicates the maximum output power of the terminal device in the second satellite network. This indicates the current transmission power of the terminal device within the first satellite network. Indicates uplink bandwidth. This represents the path loss compensation factor for the terminal device within the first satellite network. Indicates downlink path loss. Indicates the amount of power adjustment. This indicates the power control adjustment state, where N represents the power adjustment factor, and N >

1.

13. The method according to claim 12, characterized in that, The terminal device performs uplink transmission with a first power P on the uplink bandwidth b of carrier f in serving cell c. PUSCH,b,f,c Determined according to the following formula: ； Wherein, K represents the path loss compensation factor, and N represents the power adjustment factor.

14. A method for satellite handover in non-terrestrial networks, characterized in that, Satellite handover applications from the coverage area of ​​a first satellite network to the coverage area of ​​a second satellite network include: The first handover command is confirmed based on the handover request sent by the second satellite network; the first handover command includes power-related information within the coverage area of ​​the second satellite network, or the first handover command includes power-related information within the coverage area of ​​the second satellite network and the relative position information of the second satellite and the terminal device corresponding to the second satellite network. Send the first handover command to the terminal device, wherein the first handover command is used by the terminal device to determine the first power for uplink transmission to the second satellite network; The power-related information includes the transmit power of at least some of the terminal devices that have been connected within the coverage area of ​​the second satellite network when sending random access uplink channels.

15. The method according to claim 14, characterized in that, The power-related information within the coverage area of ​​the second satellite network also includes one or more of the following parameters: The average signal quality of some or all uplink beams accessed within the area; The maximum signal quality of some or all uplink beams accessed within the area; The average access power of terminal devices other than the terminal device in the second satellite network; The maximum access power of terminal devices other than the aforementioned terminal device in the second satellite network; Average path loss within the coverage area of ​​the second satellite network; The maximum path loss within the coverage area of ​​the second satellite network.

16. The method according to claim 14, characterized in that, The relative position information is used to determine the path loss compensation factor of the terminal device in the second satellite network, and the relative position information includes one or more of the following: The distance between the terminal device and the second satellite; The azimuth angle between the terminal device and the second satellite.

17. The method according to any one of claims 14-16, characterized in that, The first handover command is a RACH-free handover command, and the power adjustment amount in the first power is determined based on the RACH-free power adjustment counter. The value of the power adjustment counter is related to the parameters of the terminal device accessing the first satellite network.

18. A method for satellite handover in non-terrestrial networks, characterized in that, Satellite handover applications from the coverage area of ​​a first satellite network to the coverage area of ​​a second satellite network include: Send a handover request confirmation to the first satellite network, the handover request confirmation being used by the first satellite network to determine the first handover command; The first handover command includes power-related information within the coverage area of ​​the second satellite network, or the first handover command includes power-related information within the coverage area of ​​the second satellite network and the relative position information of the second satellite corresponding to the second satellite network and the terminal device; the first handover command is used by the terminal device to determine a first power for uplink transmission to the second satellite network; the power-related information includes the transmit power of at least some terminal devices already connected within the coverage area of ​​the second satellite network for sending random access uplink channels.

19. The method according to claim 18, characterized in that, The power-related information within the coverage area of ​​the second satellite network also includes one or more of the following parameters: The average signal quality of some or all uplink beams accessed within the area; The maximum signal quality of some or all uplink beams accessed within the area; The average access power of terminal devices other than the terminal device in the second satellite network; The maximum access power of terminal devices other than the aforementioned terminal device in the second satellite network; Average path loss within the coverage area of ​​the second satellite network; The maximum path loss within the coverage area of ​​the second satellite network.

20. The method according to claim 19, characterized in that, The first power is determined based on the power-related information and the maximum output power of the terminal device.

21. The method according to claim 19, characterized in that, The terminal transmit power of at least some of the terminal devices already connected within the area that transmit through the random access channel includes one or more of the following: The transmission power of at least some of the terminal devices transmitting message A; The transmission power of at least some of the terminal devices sending message 3.

22. The method according to any one of claims 18-21, characterized in that, The relative position information is used to determine the path loss compensation factor of the terminal device in the second satellite network, and the relative position information includes one or more of the following: The distance between the terminal device and the second satellite; The azimuth angle between the terminal device and the second satellite.

23. The method according to claim 22, characterized in that, The path loss compensation factor is determined based on the azimuth angle between the terminal device and the second satellite, and the path loss compensation factor K is determined according to the following formula: ； Wherein, δ1 represents the azimuth angle between the terminal device and the first satellite corresponding to the first satellite network, and δ2 represents the azimuth angle between the terminal device and the second satellite.

24. The method according to any one of claims 18-21, characterized in that, The first handover command is a RACH-free handover command, and the power adjustment amount in the first power is determined based on the RACH-free power adjustment counter. The value of the power adjustment counter is related to the parameters of the terminal device accessing the first satellite network.

25. A terminal device, characterized in that, include: A receiving unit is configured to receive a first handover command, which instructs the terminal device to perform a satellite handover from a first satellite network coverage area to a second satellite network coverage area. The first handover command includes power-related information within the second satellite network coverage area, or the first handover command includes power-related information within the second satellite network coverage area and the relative position information of the second satellite corresponding to the second satellite network and the terminal device. The determining unit is configured to determine, based on the first switching command, the first power for uplink transmission to the second satellite network; The power-related information includes the transmit power of at least some of the terminal devices that have been connected within the coverage area of ​​the second satellite network when sending random access uplink channels.

26. The terminal device according to claim 25, characterized in that, The power-related information within the coverage area of ​​the second satellite network also includes one or more of the following parameters: The average signal quality of some or all uplink beams accessed within the area; The maximum signal quality of some or all uplink beams accessed within the area; The average access power of terminal devices other than the terminal device in the second satellite network; The maximum access power of terminal devices other than the aforementioned terminal device in the second satellite network; Average path loss within the coverage area of ​​the second satellite network; The maximum path loss within the coverage area of ​​the second satellite network.

27. The terminal device according to claim 26, characterized in that, The first power is determined based on the power-related information and the maximum output power of the terminal device.

28. The terminal device according to claim 26, characterized in that, The signal quality is one or more of the following parameters: Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), and Reference Signal Strength Indication (RSSI).

29. The terminal device according to claim 26, characterized in that, The transmit power of at least some of the terminal devices already connected within the area that transmit random access uplink channels includes one or more of the following: The transmission power of at least some of the terminal devices transmitting message A; The transmission power of at least some of the terminal devices sending message 3.

30. The terminal device according to any one of claims 25-29, characterized in that, The relative position information is used to determine the path loss compensation factor of the terminal device in the second satellite network, and the relative position information includes one or more of the following: The distance between the terminal device and the second satellite; The azimuth angle between the terminal device and the second satellite.

31. The terminal device according to claim 30, characterized in that, The path loss compensation factor is determined based on the azimuth angle between the terminal device and the second satellite, and the path loss compensation factor K is determined according to the following formula: ； Wherein, δ1 represents the azimuth angle between the terminal device and the first satellite corresponding to the first satellite network, and δ2 represents the azimuth angle between the terminal device and the second satellite.

32. The terminal device according to claim 31, characterized in that, The terminal device performs uplink transmission with a first power P on the uplink bandwidth b of carrier f in serving cell c. PUSCH,b,f,c Determined according to the following formula: ； Where i represents the transmission timing, j represents the index of the parameter set configuration, and q d The index represents the reference signal, l represents the index of the power control adjustment state, and μ is related to the subcarrier spacing. This indicates the maximum output power of the terminal device in the second satellite network. This indicates the current transmission power of the terminal device within the first satellite network. Indicates uplink bandwidth. This represents the path loss compensation factor for the terminal device within the first satellite network. Indicates downlink path loss. Indicates the amount of power adjustment. This indicates the power control adjustment status.

33. The terminal device according to any one of claims 25-29, characterized in that, The first handover command is a RACH-free handover command, and the power adjustment amount in the first power is determined based on the RACH-free power adjustment counter. The value of the power adjustment counter is related to the parameters of the terminal device accessing the first satellite network.

34. The terminal device according to claim 33, characterized in that, The value of the power adjustment counter is the number of times the terminal device has established a connection with the first satellite network.

35. The terminal device according to claim 33, characterized in that, The power adjustment amount is also determined based on a power adjustment factor, which is determined based on the service type of the terminal device.

36. The terminal device according to claim 35, characterized in that, The terminal device performs uplink transmission with a first power P on the uplink bandwidth b of carrier f in serving cell c. PUSCH,b,f,c Determined according to the following formula: ； Where i represents the transmission timing, j represents the index of the parameter set configuration, and q d The index represents the reference signal, l represents the index of the power control adjustment state, and μ is related to the subcarrier spacing. This indicates the maximum output power of the terminal device in the second satellite network. This indicates the current transmission power of the terminal device within the first satellite network. Indicates uplink bandwidth. This represents the path loss compensation factor for the terminal device within the first satellite network. Indicates downlink path loss. Indicates the amount of power adjustment. This indicates the power control adjustment state, where N represents the power adjustment factor, and N >

1.

37. The terminal device according to claim 36, characterized in that, The terminal device performs uplink transmission with a first power P on the uplink bandwidth b of carrier f in serving cell c. PUSCH,b,f,c Determined according to the following formula: ； Wherein, K represents the path loss compensation factor, and N represents the power adjustment factor.

38. A network device, characterized in that, The network device is the network device corresponding to the first satellite network, and the network device includes: The determining unit is configured to confirm and determine a first handover command based on a handover request sent by the second satellite network. The first handover command is used to instruct the terminal device to perform a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network. The first handover command includes power-related information within the coverage area of ​​the second satellite network, or the first handover command includes power-related information within the coverage area of ​​the second satellite network and the relative position information of the second satellite corresponding to the second satellite network and the terminal device. A transmitting unit is configured to send a first handover command to a terminal device, wherein the first handover command is used by the terminal device to determine a first power for uplink transmission to the second satellite network. The power-related information includes the transmit power of at least some of the terminal devices that have been connected within the coverage area of ​​the second satellite network when sending random access uplink channels.

39. The network device according to claim 38, characterized in that, The power-related information within the coverage area of ​​the second satellite network also includes one or more of the following parameters: The average signal quality of some or all uplink beams accessed within the area; The maximum signal quality of some or all uplink beams accessed within the area; The average access power of terminal devices other than the terminal device in the second satellite network; The maximum access power of terminal devices other than the aforementioned terminal device in the second satellite network; Average path loss within the coverage area of ​​the second satellite network; The maximum path loss within the coverage area of ​​the second satellite network.

40. The network device according to claim 38, characterized in that, The relative position information is used to determine the path loss compensation factor of the terminal device in the second satellite network, and the relative position information includes one or more of the following: The distance between the terminal device and the second satellite; The azimuth angle between the terminal device and the second satellite.

41. The network device according to any one of claims 38-40, characterized in that, The first handover command is a RACH-free handover command, and the power adjustment amount in the first power is determined based on the RACH-free power adjustment counter. The value of the power adjustment counter is related to the parameters of the terminal device accessing the first satellite network.

42. A network device, characterized in that, The network device is the network device corresponding to the second satellite network, and the network device includes: The sending unit is configured to send a handover request confirmation to a first satellite network. The handover request confirmation is used by the first satellite network to determine a first handover command. The first handover command is used to instruct the terminal device to perform a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network. The first handover command includes power-related information within the coverage area of ​​the second satellite network, or the first handover command includes power-related information within the coverage area of ​​the second satellite network and the relative position information of the second satellite corresponding to the second satellite network and the terminal device; the first handover command is used by the terminal device to determine a first power for uplink transmission to the second satellite network, and the power-related information includes the transmit power of at least some terminal devices already connected within the coverage area of ​​the second satellite network for sending random access uplink channels.

43. The network device according to claim 42, characterized in that, The power-related information within the coverage area of ​​the second satellite network also includes one or more of the following parameters: The average signal quality of some or all uplink beams accessed within the area; The maximum signal quality of some or all uplink beams accessed within the area; The average access power of terminal devices other than the terminal device in the second satellite network; The maximum access power of terminal devices other than the aforementioned terminal device in the second satellite network; Average path loss within the coverage area of ​​the second satellite network; The maximum path loss within the coverage area of ​​the second satellite network.

44. The network device according to claim 43, characterized in that, The first power is determined based on the power-related information and the maximum output power of the terminal device.

45. The network device according to claim 43, characterized in that, The terminal transmit power of at least some of the terminal devices already connected within the area that transmit through the random access channel includes one or more of the following: The transmission power of at least some of the terminal devices transmitting message A; The transmission power of at least some of the terminal devices sending message 3.

46. ​​The network device according to any one of claims 42-45, characterized in that, The relative position information is used to determine the path loss compensation factor of the terminal device in the second satellite network, and the relative position information includes one or more of the following: The distance between the terminal device and the second satellite; The azimuth angle between the terminal device and the second satellite.

47. The network device according to claim 46, characterized in that, The path loss compensation factor is determined based on the azimuth angle between the terminal device and the second satellite, and the path loss compensation factor K is determined according to the following formula: ； Wherein, δ1 represents the azimuth angle between the terminal device and the first satellite corresponding to the first satellite network, and δ2 represents the azimuth angle between the terminal device and the second satellite.

48. The network device according to any one of claims 42-45, characterized in that, The first handover command is a RACH-free handover command, and the power adjustment amount in the first power is determined based on the RACH-free power adjustment counter. The value of the power adjustment counter is related to the parameters of the terminal device accessing the first satellite network.

49. A communication device, characterized in that, It includes a memory and a processor, the memory being used to store a program, and the processor being used to invoke the program in the memory to perform the method as described in any one of claims 1-24.

50. An apparatus, characterized in that, Includes a processor for calling a program from memory to perform the method as described in any one of claims 1-24.

51. A chip, characterized in that, Includes a processor for calling a program from memory, causing a device on which the chip is mounted to perform the method as described in any one of claims 1-24.

52. A computer-readable storage medium, characterized in that, It contains a program that causes a computer to perform the method as described in any one of claims 1-24.

53. A computer program product, characterized in that, Includes a program that causes a computer to perform the method as described in any one of claims 1-24.

Images