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

Abstract

The present application provides a method for non-terrestrial network (NTN) satellite handover, a terminal device, and a network device, which facilitates increasing the access success rate of RACH-less handover in an NTN cell. The method is applied to satellite handover from the coverage area of a first satellite network to the coverage area of a second satellite network, and comprises: sending first information, wherein the first information is used by the second satellite network to determine a first beam corresponding to a terminal device, and the first beam comprises one or more beams; and receiving a first handover command, the first handover command being used for instructing the terminal device to execute the satellite handover, wherein the first beam is related to a first resource and / or a second resource pre-configured for the satellite handover by the second satellite network.

Description

Method, terminal equipment and network equipment for non-terrestrial network satellite switching Technical Field

[0001] The present application relates to the field of communication technology, and more specifically, to a method, terminal equipment, and network equipment for non-terrestrial network satellite switching. Background Art

[0002] In order to improve user experience and reduce the delay of terminal equipment switching from a source cell to a target cell, random access channel-less (RACH-less) handover is introduced.

[0003] However, in some communication systems (e.g., non-terrestrial networks (NTN) systems), the propagation delay between terminal devices and network equipment is significant. When performing RACH-free handover in these communication systems, how to pre-configure uplink resources to improve the success rate of terminal device handovers is a problem that needs to be solved.

[0004] Summary of the Invention

[0005] The present application provides a method, terminal device, and network device for non-terrestrial network satellite handover. The following describes various aspects of the embodiments of the present application.

[0006] In a first aspect, a method for non-terrestrial network satellite switching is provided, which is applied to satellite switching from a first satellite network coverage area to a second satellite network coverage area, including: sending first information, where the first information is used by the second satellite network to determine a first beam corresponding to the terminal device, the first beam including one or more beams; receiving a first switching command, where the first switching command is used to instruct the terminal device to perform the satellite switching; wherein the first beam is related to a first resource and / or a second resource preconfigured by the second satellite network for the satellite switching.

[0007] In a second aspect, a method for non-terrestrial network satellite switching is provided, which is applied to satellite switching from a first satellite network coverage area to a second satellite network coverage area, including: receiving first information sent by a terminal device, the first information is used by the second satellite network to determine a first beam corresponding to the terminal device, the first beam including one or more beams; sending the first information to the second satellite network; sending a first switching command to the terminal device, the first switching command is used to instruct the terminal device to perform the satellite switching; wherein the first beam is related to the first resource and / or second resource preconfigured by the second satellite network for the satellite switching.

[0008] According to a third aspect, a method for satellite switching of a non-terrestrial network is provided, which is applied to satellite switching from a first satellite network coverage area to a second satellite network coverage area, and includes: receiving first information sent by the first satellite network, the first information being used to determine a first beam corresponding to the second satellite network and a terminal device, the first beam including one or more beams; sending a switching request confirmation to the first satellite network according to a switching request sent by the first satellite network, the switching request confirmation being used by the first satellite network to send a first switching command to the terminal device, the first switching command being used to instruct the terminal device to perform the satellite switching; wherein the first beam is related to the first resource and / or second resource preconfigured by the second satellite network for the satellite switching.

[0009] In a fourth aspect, a terminal device is provided, including: a sending unit for sending first information, wherein the first information is used by the second satellite network to determine a first beam corresponding to the terminal device, and the first beam includes one or more beams; a first receiving unit for receiving a first switching command, wherein the first switching command is used to instruct the terminal device to perform a satellite switching from the first satellite network coverage area to the second satellite network coverage area; wherein the first beam is related to the first resource and / or second resource preconfigured by the second satellite network for the satellite switching.

[0010] In a fifth aspect, a network device is provided, which is a network device corresponding to a first satellite network, and the network device includes: a receiving unit, used to receive first information sent by a terminal device; a first sending unit, used to send the first information to a second satellite network, the first information is used by the second satellite network to determine a first beam corresponding to the terminal device, and the first beam includes one or more beams; a second sending unit, used to send a first switching command to the terminal device, the first switching command is used to instruct the terminal device to perform satellite switching from the first satellite network coverage area to the second satellite network coverage area; wherein the first beam is related to the first resource and / or second resource preconfigured by the second satellite network for the satellite switching.

[0011] In a sixth aspect, a network device is provided, which is a network device corresponding to a second satellite network, and the network device includes: a receiving unit, used to receive first information sent by a first satellite network, the first information is used to determine a first beam corresponding to the second satellite network and a terminal device, and the first beam includes one or more beams; a first sending unit, used to send a switching request confirmation to the first satellite network according to the switching request sent by the first satellite network, the switching request confirmation is used by the first satellite network to send a first switching command to the terminal device, and the first switching command is used to instruct the terminal device to perform a satellite switching from the first satellite network coverage area to the second satellite network coverage area; wherein the first beam is related to the first resource and / or second resource preconfigured by the second satellite network for the satellite switching.

[0012] In a seventh aspect, a communication device is provided, comprising a memory and a processor, wherein the memory is used to store a program, and the processor is used to call the program in the memory to execute the method described in any one of the first to third aspects.

[0013] In an eighth aspect, a device is provided, comprising a processor for calling a program from a memory to execute the method as described in any one of the first to third aspects.

[0014] In a ninth aspect, a chip is provided, comprising a processor for calling a program from a memory so that a device equipped with the chip executes the method described in any one of the first to third aspects.

[0015] In a tenth aspect, a computer-readable storage medium is provided, on which a program is stored, wherein the program enables a computer to execute the method as described in any one of the first to third aspects.

[0016] In an eleventh aspect, a computer program product is provided, comprising a program, wherein the program enables a computer to execute the method according to any one of the first to third aspects.

[0017] In a twelfth aspect, a computer program is provided, wherein the computer program enables a computer to execute the method as described in any one of the first to third aspects.

[0018] In an embodiment of the present application, before receiving the first handover command, the terminal device may send first information to the second satellite network to determine that the second satellite network and the terminal device share the first beam corresponding to the terminal device. The second satellite network preconfigures the first resource and / or the second resource based on the determined first beam. This allows the terminal device to know the first beam that carries the first resource authorization, thereby improving the access success rate for handover using the first resource. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG1 is a wireless communication system used in an embodiment of the present application.

[0020] FIG2 is an NTN system used in an embodiment of the present application.

[0021] FIG3 is another NTN system applied in an embodiment of the present application.

[0022] FIG4 is a flow chart of a method for NTN satellite switching provided in an embodiment of the present application.

[0023] FIG5 is a flowchart of a possible implementation of the method shown in FIG4 .

[0024] FIG6 is a flowchart of another possible implementation of the method shown in FIG4 .

[0025] FIG7 is a flow chart of another method for NTN satellite switching provided in an embodiment of the present application.

[0026] FIG8 is a schematic diagram of an implementation method for determining a switching path loss of a terminal device.

[0027] FIG9 is a schematic structural diagram of a terminal device provided in an embodiment of the present application.

[0028] FIG10 is a schematic structural diagram of a network device provided in an embodiment of the present application.

[0029] FIG11 is a schematic structural diagram of another network device provided in an embodiment of the present application.

[0030] FIG12 is a schematic structural diagram of another terminal device provided in an embodiment of the present application.

[0031] FIG13 is a schematic structural diagram of another network device provided in an embodiment of the present application.

[0032] FIG14 is a schematic structural diagram of another network device provided in an embodiment of the present application.

[0033] FIG15 is a schematic structural diagram of a communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0034] The following will describe the technical solutions in the embodiments of this application in conjunction with the drawings in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of the embodiments. With respect to the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0035] The embodiments of the present application can be applied to various communication systems. For example, the embodiments of the present application can be applied to global system of mobile communication (GSM) system, code division multiple access (CDMA) system, wideband code division multiple access (WCDMA) system, general packet radio service (GPRS), long term evolution (LTE) system, advanced long term evolution (LTE-A) system, new radio (NR) system, evolution system of NR system, LTE-based access to unlicensed spectrum (LTE-U) system on unlicensed spectrum, NR-based access to unlicensed spectrum (NR-U) system on unlicensed spectrum, NTN system, universal mobile telecommunication system (UMTS), wireless local area networks (WLAN), wireless fidelity (WiFi), and fifth generation communication (5th-generation, 5G) system. The embodiments of the present application can also be applied to other communication systems, such as future communication systems. The future communication system may be, for example, a sixth-generation (6G) mobile communication system or a satellite communication system.

[0036] Traditional communication systems support a limited number of connections and are easy to implement. However, with the development of communication technology, communication systems can not only support traditional cellular communications, but also support one or more other types of communications. For example, a communication system can support one or more of the following communications: 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, etc. The embodiments of the present application can also be applied to communication systems that support the above-mentioned communication methods.

[0037] The communication system in the embodiment of the present application can be applied to a carrier aggregation (CA) scenario, a dual connectivity (DC) scenario, and a standalone (SA) networking scenario.

[0038] The communication system in the embodiments of the present application can be applied to unlicensed spectrum. The unlicensed spectrum can also be considered a shared spectrum. Alternatively, the communication system in the embodiments of the present application can also be applied to licensed spectrum. The licensed spectrum can also be considered a dedicated spectrum.

[0039] The embodiments of the present application can be applied to NTN systems. As examples, the NTN systems may include 4G-based NTN systems, NR-based NTN systems, Internet of Things (IoT)-based NTN systems, and narrowband Internet of Things (NB-IoT)-based NTN systems.

[0040] A communication system may include one or more terminal devices. The terminal devices mentioned in the embodiments of the present application may also be referred to as user equipment (UE), access terminal, subscriber unit, subscriber station, mobile station, mobile station (MS), mobile terminal (MT), remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device, etc.

[0041] 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, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA) device, a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a wearable device, a terminal device in a next-generation communication system (e.g., a NR system), or a terminal device in a future-evolved public land mobile network (PLMN) network.

[0042] In some embodiments, a 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 connection capabilities. As some specific examples, the terminal device may be a mobile phone, a tablet computer, a laptop computer, a PDA, a mobile internet device (MID), a wearable device, a virtual reality (VR) device, an augmented reality (AR) device, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical surgery, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, etc.

[0043] In some embodiments, the terminal device can be deployed on land. For example, the terminal device can be deployed indoors or outdoors. In some embodiments, the terminal device can be deployed on the water, such as on a ship. In some embodiments, the terminal device can be deployed in the air, such as on an airplane, a balloon, or a satellite.

[0044] In addition to the terminal device, the communication system may also include one or more network devices. The network device in the embodiment of the present application may be a device for communicating with the terminal device, and the network device may also be referred to as an access network device or a radio access network device. The network device may be, for example, a base station. The network device in the embodiment of the present application may refer to a radio access network (RAN) node (or device) that connects the terminal device to a wireless network. The base station can broadly cover various names as follows, or be replaced with the following names, such as: NodeB, evolved NodeB (eNB), next generation NodeB (gNB), relay station, access point, transmission point (transmitting and receiving point, TRP], transmitting point (transmitting point, TP]), master station MeNB, secondary station SeNB, multi-standard radio (MSR) node, home base station, network controller, access node, wireless node, access point (AP), transmission node, transceiver node, baseband unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (distributed unit, DU), positioning node, etc. The base station can be a macro base station, a micro base station, a relay node, a donor node or the like, or a combination thereof. The base station can also refer to a communication module, a modem or a chip used to be set in the aforementioned equipment or device. The base station can also be a mobile switching center and a device that performs the base station function in D2D, V2X, and M2M communications, a network side device in a 6G network, a device that performs the base station function in a future communication system, etc. The base station can support networks with the same or different access technologies. The embodiments of the present application do not limit the specific technology and specific device form adopted by the network equipment.

[0045] 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 based on the location of the mobile base station. In other examples, a helicopter or drone can be configured to act as a device that communicates with another base station.

[0046] In some deployments, the network device in the embodiments of the present application may refer to a CU or a DU, or the network device may include a CU and a DU. The gNB may also include an AAU.

[0047] By way of example and not limitation, in embodiments of the present application, a network device may be mobile, for example, a mobile device. In some embodiments of the present application, the network device may be a satellite or balloon station. In some embodiments of the present application, the network device may also be a base station located on land, water, or the like.

[0048] In an embodiment of the present application, the network device can provide services for a cell, and the terminal device communicates with the network device through the transmission resources used by the cell (for example, frequency domain resources, or spectrum resources). The cell can be a cell corresponding to the network device (for example, a base station). The cell can belong to a macro base station or a base station corresponding to a small cell. The small cells here may include: metro cells, micro cells, pico cells, femto cells, etc. These small cells have the characteristics of small coverage and low transmission power, and are suitable for providing high-speed data transmission services.

[0049] For example, Figure 1 is a schematic diagram of the architecture of a communication system provided in an embodiment of the present application. As shown in Figure 1, the communication system 100 may include a network device 110, which may be a device that communicates with a terminal device 120 (or also referred to as a communication terminal or terminal). The network device 110 may provide communication coverage for a specific geographic area and may communicate with terminal devices located within the coverage area.

[0050] Figure 1 exemplarily shows a network device and two terminal devices. In some embodiments of the present 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, which is not limited in the embodiments of the present application.

[0051] For example, Figure 2 illustrates an architecture diagram of the aforementioned NTN system. NTN system 200 in Figure 2 utilizes satellite 210 as an aerial platform. As shown in Figure 2, the satellite radio access network includes satellite 210, service link 220, feeder link 230, terminal equipment 240, gateway (GW) 250, and network 260, including base stations and a core network.

[0052] Satellite 210 is a spacecraft based on a space platform. Service link 220 refers to the link between satellite 210 and terminal device 240. Feeder link 230 refers to the link between gateway 250 and satellite 210. Earth-based gateway 250 connects satellite 210 to a base station or core network, depending on the architecture selected.

[0053] The NTN architecture shown in Figure 2 is a bent-pipe transponder architecture. In this architecture, a base station is located on Earth behind gateway 250, with satellite 210 acting as a relay. Satellite 210 operates as a relay, forwarding signals from feeder link 230 to service link 220, or vice versa. In other words, satellite 210 does not function as a base station; communications between terminal device 240 and base stations in network 260 must be relayed through satellite 210.

[0054] Figure 3 illustrates another NTN system architecture. As shown in Figure 3, satellite radio access network 300 includes satellite 310, service link 320, feeder link 330, terminal equipment 340, gateway 350, and network 360. Unlike Figure 2, satellite 310 has a base station 312, while network 360 behind gateway 350 consists solely of a core network.

[0055] The NTN architecture shown in Figure 3 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.

[0056] The communication system of the architecture shown in Figures 2 and 3 may include multiple network devices, and each network device may include other number of terminal devices within its coverage area, which is not limited in the embodiments of the present application.

[0057] In the embodiment of the present application, the communication system shown in Figures 1 to 3 may also include other network entities such as a mobility management entity (MME) and an access and mobility management function (AMF), but the embodiment of the present application does not limit this.

[0058] It should be understood that in the embodiments of the present application, a device having a communication function in a network / system may be referred to as a communication device. Taking the communication system 100 shown in FIG1 as an example, the communication device may include a network device 110 and a terminal device 120 having a communication function. The network device 110 and the terminal device 120 may be the specific devices described above and will not be described in detail here. The communication device may also include other devices in the communication system 100, such as a network controller, a mobility management entity, and other network entities, which are not limited in the embodiments of the present application.

[0059] For ease of understanding, some relevant technical knowledge involved in the embodiments of this application is first introduced. The following related technologies can be combined with the technical solutions of the embodiments of this application as optional solutions, and they all fall within the scope of protection of the embodiments of this application. The embodiments of this application include at least part of the following contents.

[0060] NTN system

[0061] As communication technologies develop, communication systems (e.g., 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.

[0062] NTN refers to a network or network segment that utilizes radio frequency (RF) resources on satellite or unmanned aerial system (UAS) platforms. Taking satellites as an example, communications satellites are categorized by orbital altitude into low Earth orbit (LEO), medium Earth orbit (MEO), geostationary Earth orbit (GEO), and high elliptical orbit (HEO). LEO is an Earth-centered orbit with an altitude of 2,000 kilometers or less, or with at least 11.25 cycles per day and 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 speed (mobility) but in predictable or deterministic orbits.

[0063] Satellites at different orbital altitudes have different orbital periods.

[0064] LEO: Typical altitude is 250-1500 km, with an orbital period of 90-120 minutes.

[0065] MEO: Typical altitude is 5,000-25,000 km, and orbital period is 3-15 hours.

[0066] GEO: Altitude is approximately 35,786 kilometers, and the orbital period is 24 hours.

[0067] As shown in Figures 2 and 3, using satellites as an example, typical scenarios for terminal devices accessing an NTN system involve either a transparent NTN payload or a regenerative NTN payload. The bent-pipe transponder architecture shown in Figure 2 corresponds to the transparent NTN payload, while the regenerative transponder architecture shown in Figure 3 corresponds to the regenerative NTN payload.

[0068] In an NTN system, the propagation delay between terminal devices and network equipment depends primarily on the altitude of the satellite or airborne platform and the type of payload in the NTN. Compared to terrestrial networks (TN), the propagation delay between terminal devices and network equipment in an NTN system is much longer. For example, in the cellular networks used in traditional NR, the propagation delay of terrestrial mobile systems is typically less than 1 millisecond, while the propagation delay of NTN systems ranges from a few milliseconds to hundreds of milliseconds.

[0069] NTN systems are highly mobile, and aerial platforms like satellites cover large areas. Therefore, terminal devices must switch cells promptly to maintain stable communications. For simplicity, the following explanation uses satellites as an example.

[0070] In the NTN system, as satellites move, terminal devices must perform satellite handover from a source NTN satellite (NTN1) to a target NTN satellite (NTN2). During the handover process, the terminal device typically starts two timers to enforce timing. These timers are timer T304 and timer T430.

[0071] The terminal device starts the timer T304 when starting the handover. During the handover process, once the timer T304 expires, the terminal device initiates a radio resource control (RRC) connection re-establishment process to the target NTN cell.

[0072] During downlink (DL) and uplink (UL) synchronization, the terminal device starts timer T430. As previously mentioned, the source satellite NTN1 and the terminal device on Earth will move relative to each other, so the auxiliary information (NTN-config) of the source satellite NTN1 may be subject to validity issues. Timer T430 is used to ensure that the terminal device can continuously obtain valid auxiliary information from the source satellite NTN1. For example, timer T430 can be used to control the terminal device to obtain valid auxiliary information from the system information block (SIB) 19, thereby ensuring that the auxiliary information from the source NTN1 obtained by the terminal device before the handover is completed is valid.

[0073] Assistance information for source satellite NTN1 includes, for example, satellite ephemeris and common timing advance (TA) parameters. For NTN1, the network can broadcast ephemeris information and common TA parameters. For example, SIB19 contains satellite assistance information for NTN access. Before connecting to NTN2, the terminal device must have a valid global navigation satellite system (GNSS) position, satellite ephemeris information, and common TA parameters.

[0074] RACH-free handover (HO)

[0075] When the source cell, target cell, and terminal device are synchronized, a RACH-free handover solution can be introduced to reduce handover latency and improve user experience. In a synchronous network, the subframe boundaries between the source cell and target cell can be assumed to be aligned. Therefore, the terminal device can switch from the source cell to the target cell at the time agreed upon by the three parties, without the need for a random access process. For example, when the source cell, target cell, and terminal device are synchronized, the terminal device can switch from the source cell to the target cell at the system frame number (SFN) agreed upon by the three parties, without the need for random access.

[0076] One of the main purposes of the random access channel (RACH) procedure during a handover is to obtain the target cell's TA. In the case of a RACH handover, the RACH procedure allows the terminal device to obtain the target cell's TA. In the absence of a 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.

[0077] Another purpose of the RACH process during handover is to obtain uplink permission transmission. In the absence of a RACH process in the target cell, an uplink grant needs to be allocated in the target cell. In some embodiments, for the initial UL transmission in a RACH-free handover, a pre-allocated grant in a RACH-free handover command is supported. That is, the target cell can be pre-allocated via an uplink grant (UL-grant) in the handover command. The pre-allocated uplink grant can remain valid for a period of time, starting from the time the terminal device achieves synchronization with the target cell. For example, when a RACH-free handover is performed in the NR terrestrial network, the propagation delay between the terminal device and the network device is low. Based on the delay information propagated between the terminal device and the network device, the target cell can appropriately configure the time domain position of the uplink resource 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.

[0078] For the initial UL transmission in a RACH-free handover, support for pre-allocated grants in the RACH-free handover command is required. In an 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 satellites with the same gateway or network equipment (e.g., gNB).

[0079] Compared to cellular networks used in some communication systems (e.g., NR), the propagation delay between terminal devices and satellites in NTN is relatively long, and the propagation delay of the portion of the air interface where the terminal device correctly receives the handover command is also relatively long. When RACH-free handover is introduced in the NTN system, due to the large propagation delay, the terminal device may miss the configured uplink resources during access to the target cell, resulting in handover access failure. For example, in NTN's RACH-free handover, 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 retransmissions or hybrid automatic repeat request (HARQ) retransmissions when forwarding the handover command, which increases the propagation delay of the terminal device's air interface, making access unsuccessful.

[0080] In some scenarios, NTN, like other communication systems (e.g., 5G (NR)), uses beams to achieve coverage. For example, each serving cell carries one or more synchronization signal blocks (SSBs) or synchronization signal / physical broadcast channel (SS / PBCH) blocks. For simplicity, the term "SSB" will be used to represent either synchronization signal block or synchronization signal / physical broadcast channel (SS / PBCH) block.

[0081] SSB beams are usually static or semi-static. The maximum number of SSB beams per cell is between 4 and 64, which can form a (beam) grid covering the entire cell. Typically, after the terminal device is powered on, it searches and measures the beam and maintains a set of candidate beam sets. The candidate beam set can include beams from multiple cells. The terminal device can measure the signal of the beam to determine the beam quality. For example, the terminal device can measure the reference signal received power (RSRP) of the beam synchronization signal (SS), namely SS-RSRP. For another example, the terminal device can measure the reference signal received quality (RSRQ) based on the synchronization signal, namely SS-RSRQ. For another example, the terminal device can measure the signal-to-noise and interference ratio (SINR) of the beam based on the synchronization signal, namely SS-SINR.

[0082] In some embodiments, a network device (e.g., a gNB) may know the appropriate beam based on Layer 3 (L3) measurement reports or location reports from a terminal device. L3 measurement reports include beam-level results. However, in some cases, the network device may not have this information, such as when there is no location report.

[0083] As mentioned above, in RACH-free handover, grants are pre-assigned. If the appropriate beam for the terminal device cannot be determined, allocating grants across all beams in the target cell will result in resource loss, while allocating grants across only a few beams may cause the terminal device to miss the configured uplink resources.

[0084] For example, in 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-free switching process, making it impossible to pre-configure appropriate uplink resources.

[0085] For another example, when conditional handover (CHO) is combined with RACH-free handover, the time point of triggering the handover is uncertain, and it may also be impossible to pre-configure appropriate uplink resources.

[0086] In summary, when RACH-free handover is introduced in the NTN scenario, how to reserve and pre-configure uplink resources in the RACH-free handover command to improve the success rate of handover access of terminal devices becomes a problem that needs to be solved.

[0087] It should be noted that the problem mentioned above in which handover failure occurs due to large propagation delay and inappropriate reserved resource configuration when RACH-free handover is introduced in the NTN system is only an example. The embodiments of the present application can be applied to any type of handover scenario in which the propagation delay is large and the terminal device cannot communicate with the target cell through random access.

[0088] Based on this, embodiments of the present application propose a method for NTN satellite handover. Using this method, a terminal device can send a selected beam or beam measurement information to a target satellite network before performing a cell handover. This allows the target satellite network to configure uplink resources on an appropriate beam based on this information, thereby improving the handover success rate.

[0089] For ease of understanding, the method proposed in an embodiment of the present application is described in detail below with reference to FIG4 . FIG4 is written from the perspective of the interaction between a terminal device, a first satellite network, and a second satellite network. The method shown in FIG4 is applied to a satellite handover from a first satellite network coverage area to a second satellite network coverage area.

[0090] The terminal device is any of the terminal devices described above. In some embodiments, the terminal device is a communication device that provides services to satellites in an NTN system. In some embodiments, the terminal device is a communication device with a low service transmission rate.

[0091] The first and second satellite networks are NTN networks that integrate ground-based infrastructure and aerial platforms such as satellites. As previously mentioned, the satellites and other aerial platforms in the first and second satellite networks can serve as network devices, providing services, or acting as relays. Taking satellites as an example, the network devices corresponding to the first and second satellite networks can be satellites or ground-based base stations. For simplicity, the satellite corresponding to the first satellite network can be referred to as the first satellite, and the satellite corresponding to the second satellite network can be referred to as the second satellite. The network devices corresponding to the first satellite network can be referred to as the first network devices, and the network devices corresponding to the second satellite network can be referred to as the second network devices.

[0092] The first satellite network is the NTN network currently providing services to the terminal device. The first satellite network may also be referred to as the source NTN or source satellite network. In some embodiments, the first satellite network provides services to the terminal devices within the coverage area through its corresponding network devices.

[0093] The network device corresponding to the first satellite network is the communication device currently providing services to the terminal device. In some embodiments, the network device may be a device in relative motion with the terminal device. For example, the first network device may be a base station on a satellite providing services to the terminal device. In another example, the first network device may be a base station installed on a low-altitude aircraft. In some embodiments, the network device may be 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 device may be a base station on the ground communicating with the satellite via a gateway.

[0094] 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 a source cell. In some embodiments, the first satellite network coverage area may include one or more terrestrial network cells.

[0095] The second satellite network is an NTN network that provides services to the terminal device 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 the terminal devices within its coverage area through its corresponding network equipment. In some embodiments, the first satellite network may determine multiple satellite networks that can provide services to the terminal device 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 measurement.

[0096] The network device corresponding to the second satellite network is the next communication device to provide services to the terminal device. In some embodiments, the second network device can be a device that moves relative to the terminal device, or can be a device that is stationary relative to the terminal device or relative to the earth, which will not be described in detail here.

[0097] 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 a target cell. In some embodiments, the second satellite network coverage area may include one or more terrestrial network cells.

[0098] The satellite handover may be a handover of a satellite corresponding to an area where the terminal device is located. For example, the satellite handover may be a cell handover. For example, the physical cell identity (PCI) of the coverage area remains unchanged during the satellite handover.

[0099] 4 , in step S410 , the terminal device sends first information to the first satellite network.

[0100] The first information is used by the second satellite network to determine a first beam corresponding to the terminal device, so that the second satellite network pre-configures a first resource for satellite handover for the terminal device. The first beam is also used by the second satellite network to schedule a second resource related to satellite handover. In other words, the first beam is associated with the first resource and / or second resource used by the second satellite network for satellite handover.

[0101] In some embodiments, the first resource may be a configured or preconfigured resource. For example, the first resource may be a reserved resource for the terminal device to perform satellite handover. In another example, the first resource may include an uplink grant for satellite handover.

[0102] In some embodiments, the second resource may be a scheduled uplink resource. The uplink resource may be dynamically scheduled.

[0103] Exemplarily, the first resource is a reserved resource for satellite handover, and the second resource is a scheduled uplink resource, where the uplink resource is used by the terminal device to perform satellite handover. For example, the first resource is a reserved resource for the terminal device to send an initial uplink transmission, and the second resource is a resource dynamically scheduled via a physical downlink control channel (PDCCH).

[0104] The first beam is a beam among all beams used by the second satellite network to cover the service area. In some embodiments, the first beam can be a single beam. In some embodiments, the first beam can be multiple beams. Typically, the number of beams in the first beam is smaller than the number of all beams in the second satellite network. Therefore, the second satellite network allocates uplink resources to only some of the beams, effectively saving resources.

[0105] The terminal device can determine the multiple beams of the second satellite network in a variety of ways. In some embodiments, before the switching process, after the first satellite network informs the terminal device of the target satellite network to switch to (i.e., the second satellite network), the terminal device can determine the multiple beams of the second satellite network by measurement. In some embodiments, before the switching process, the first satellite network can provide the terminal device with information indicating the multiple beams in the second satellite network. This information can identify multiple beams, or identify the beam information by identifying the reference signal transmitted via the beam. For example, the terminal device can identify the beam information through SSB. For another example, after receiving the information, the terminal device can identify and measure one or more characteristics of the reference signal to determine the beam. The one or more characteristics are, for example, power, RSRP, RSRQ, etc.

[0106] The first beam can be one or more beams that the terminal device can use to access the second satellite network, or 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 via the first beam. When the second satellite network configures or pre-configures first resources 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.

[0107] The first beam is associated with first resources preconfigured by the second satellite network for satellite handover. For example, the second satellite network may allocate a grant 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 a handover request acknowledgment sent to the first satellite network.

[0108] The first resources may be time-frequency resources reserved by the second satellite network for the terminal device to perform satellite handover. For example, the first resources may be used for the terminal device's initial uplink transmission during a RACH-free handover. Because the terminal device uses these resources only during handover, the first resources are typically preconfigured by the second satellite network. It should be understood that in certain scenarios, the second satellite network may also dynamically configure the first resources.

[0109] In some embodiments, the first resource may include one or more pre-allocated grants, for example, and the terminal device may access the resource using the pre-allocated grants.

[0110] The second resource may be a resource scheduled by the second satellite network based on communication needs to facilitate uplink transmission by the terminal device. In some embodiments, the second resource may be an uplink resource dynamically scheduled by the second satellite network. In some embodiments, the second resource may be an uplink resource scheduled in real time by the second satellite network.

[0111] Exemplarily, the second satellite network may transmit a PDCCH on the first beam. For example, in RACH-free handover, the second satellite network does not transmit a media access control control element (MAC CE) with a contention resolution identifier of the terminal device, but instead transmits a PDCCH or a physical downlink shared channel (PDSCH) addressable to a cell-radio network temporary identifier (C-RNTI).

[0112] For example, before completing the RACH-free handover, the MAC entity may not select the uplink grant corresponding to the logical channel corresponding to the data radio bearer (DRB). The uplink grant is used for the HARQ process of the initial UL transmission. If a PDCCH addressed to the C-RNTI scheduling DL / UL is received after the initial UL transmission, the RACH-free handover is considered to be completed.

[0113] In some embodiments, the first resource may include one or more pre-allocated uplink (UL) grants. These grants may be used by the terminal device to access the network. For example, based on the measurement report, the second satellite network may provide the terminal device with one or more UL grants. The one or more UL grants may each be associated with a first beam in the second satellite network.

[0114] Exemplarily, the terminal device may use available UL grants (RRC, MAC, PHY) to send an initial uplink transmission. The initial uplink transmission includes messages such as RRCReconfigurationComplete.

[0115] 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 by using the SSB index. For example, the first beam is also used to carry one or more synchronization signal blocks for the terminal device to perform satellite handover. The indexes of the one or more synchronization signal blocks are associated with the first resource.

[0116] Exemplarily, the first information may also include the index of one or more SSBs measured by the terminal device. The second satellite network may determine the first beam by the SSB index. In the case where a single SSB is mapped to one beam, since the beam coverage is much larger than the TN and different frequency reuse patterns are considered between the beams, the SSB detectable at a specific point in time and the location of the UE will represent the appropriate beam for subsequent communications. However, in the NTN, there may be a situation where one or more SSBs are associated with one beam. If multiple SSBs are mapped to one beam, since the same satellite setting and propagation are shared, the channel quality is similar or exactly the same. In this case, the terminal device may not be able to perform SSB selection in RACH-free switching. To solve this problem, when the second satellite network allocates the terminal device a first beam for RACH-free switching, the first beam may be associated with an SSB index. The terminal device may know the reservation information related to the pre-allocated resources associated with this SSB index.

[0117] For example, the second satellite network may specify one or more SSB index-related grants. The SSB index-related grants are used to indicate SSBs available for RACH handover and corresponding resources. If a terminal device accesses these SSBs, it can directly synchronize and access the network.

[0118] The first information can include various types of content to facilitate the second satellite network's determination of the first beam. In some embodiments, the first information can directly indicate the first beam selected by the terminal device. That is, the terminal device can independently determine the appropriate first beam and then notify the second satellite network via the first satellite network. For example, the terminal device can measure multiple beams of the second satellite network, determine the first beam based on the measurement results, and then directly notify the second satellite network of this information via the first information. In some embodiments, the first information can include multiple first measurement results of the terminal device measuring 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 can also be a measurement report. For example, the terminal device can measure the strength of each reference signal, generate a respective measurement report, and provide the measurement report to the second satellite network.

[0119] In some embodiments, when a terminal device performs beam selection, the beam selection may be periodic, aperiodic, or triggered. During satellite handover, the second satellite network may know the beam selected by the terminal device through the association between the pre-assigned grant and the beam or SSB, and may use the corresponding beam to schedule subsequent transmissions.

[0120] The first measurement result may be a result of the terminal device measuring a reference signal of the beam. In some embodiments, the reference signal may be a synchronization signal block reference signal (SSB-reference signal, SSB-RS), or a channel state information (CSI) reference signal (reference signal, RS), i.e., CSI-RS, or both CSI-RS and SSB-RS.

[0121] The first measurement result may be used to indicate the signal quality of the beam reference signal. Signal quality may also be referred to as signal strength. To indicate signal quality, the first measurement result may be the RSRP, RSRQ, or SINR described above, or a reference signal strength indication (RSSI), or a combination thereof.

[0122] 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 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 identical or similar.

[0123] For example, the first measurement result corresponding to the first beam may be a maximum value among multiple first measurement results. In this scenario, the first beam may include one beam. For example, the second satellite network may generate an UL grant associated with the reference signal with the highest strength.

[0124] For example, the first measurement result corresponding to the first beam may be a specified number of larger measurement results among the plurality of first measurement results. That is, the number of first beams may be specified. For example, the first measurement result corresponding to the first beam may be the largest M values ​​among the plurality of first measurement results, where M is greater than 1. In this scenario, the first beam may include multiple beams. For example, the second satellite network may generate UL grants for a specified number of beams having the best quality level (e.g., based on strength) among the measured reference signals.

[0125] Exemplarily, the first measurement result corresponding to the first beam may be a plurality of measurement results greater than a first threshold. That is, the signal quality corresponding to the first beam may be specified. In this scenario, the first beam may include at least one beam. For another example, the second satellite network may generate a UL grant for a reference signal that is at least greater than an RSRP threshold level. In order to ensure that the first beam determined by the terminal device is consistent with the second satellite network, the second satellite network may 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 selects. 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.

[0126] In some embodiments, the terminal device may receive the second information in the received first switching command.

[0127] In some embodiments, the terminal device may receive second information after sending the first information. The second information is used to indicate the first beam. After receiving the first switching command, the terminal device may detect a downlink channel sent by the second satellite network based on the first beam indicated by the second information.

[0128] For example, the first beam may be indicated by an identifier of a reference signal associated with the first beam. For example, the second satellite network may specify the reference signal associated with the UL grant by associating an identifier (e.g., an index) of the reference signal with the UL grant. Alternatively, the second satellite network may include the identifier in a message (e.g., an RRC message) providing the UL grant to the terminal device.

[0129] Before the terminal device performs satellite handover, the first information may be sent to the first satellite network at different times. In some embodiments, the first information may 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 may measure multiple beams of the second satellite network to generate the first information. For example, after the first satellite network determines the second satellite network through a handover decision, it may 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 first information to be sent. In some embodiments, the first information may 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 may include the first information in the first measurement report used for handover.

[0130] In step S420, 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 by the first satellite network to the second satellite network. Furthermore, the second information indicating the first beam sent by the second satellite network also needs to be forwarded by the first satellite network to the terminal device.

[0131] In some embodiments, the first information may be included in a handover request sent by the first satellite network to the second satellite network, so as to reduce the interaction between the two satellite networks and save air interface resources.

[0132] In some embodiments, the second information may be included in a handover request confirmation sent by the second satellite network to the first satellite network, which may also reduce the interaction between the two satellite networks and save air interface resources.

[0133] Continuing to refer to FIG. 4 , in step S430 , a first switching command is received.

[0134] The first handover command received by the terminal device comes from the first satellite network. That is, the first satellite network currently providing service to the terminal device instructs the terminal device to perform a handover. In some embodiments, a first network device corresponding to the first satellite network sends the first handover command to the terminal device.

[0135] The first handover command is used to trigger the terminal device to perform a handover. In some embodiments, the first satellite network may trigger the handover by sending RRC signaling to the terminal device. For example, the first satellite network may trigger the RACH-free handover by sending an RRC reconfiguration message to the terminal device. In some embodiments, the first satellite network may trigger the handover using separately configured information. For example, messages related to the RACH-free handover command may be sent using additional dedicated signaling.

[0136] 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. In some embodiments, due to satellite movement, the area where the terminal device is located changes from the first satellite network coverage area to the second satellite network coverage area, necessitating a handover. In some embodiments, due to movement of the terminal device or edge communication, the area where the terminal device is located changes from the first satellite network coverage area to the second satellite network coverage area, necessitating a handover.

[0137] The first handover command can be a satellite handover command in various forms. In some embodiments, the first handover command can be a command that prevents the terminal device from performing satellite handover via the RACH. For example, the first handover command is a RACH-free handover command. In another example, the first handover command does not provide resources for the terminal device to perform random access. The embodiments of the present application will be described in detail below using RACH-free handover as an example.

[0138] 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 be switched from the first satellite network to the second satellite network due to satellite movement or other reasons, RACH-free handover may be preferred to reduce handover latency.

[0139] When satellite handover is RACH-free, the first satellite network must identify a second satellite network that meets the RACH-free handover conditions before sending the first handover command. As previously mentioned, there are multiple satellite networks that can provide service to the terminal device. These satellite networks can be referred to as candidate satellite networks. If no second satellite network meets the RACH-free handover conditions among the multiple candidate satellite networks, the terminal device can perform satellite handover according to 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 conventional handover command.

[0140] In some embodiments, the first satellite network may determine the second satellite network based on a measurement report from a terminal device. For example, the first satellite network may determine a second satellite network that meets certain conditions based on measurement results in the measurement report. In some embodiments, the first satellite network may independently determine the second satellite network. For example, after the first satellite network has determined multiple satellite networks that can provide service to the terminal device, it may determine the second satellite network based on the location information or movement information of the terminal device.

[0141] In some embodiments, when the satellite handover is RACH-free handover, the terminal device may send a first measurement report to the first satellite network. The first measurement report may include multiple second measurement results of the terminal device measuring reference signals of multiple candidate satellite networks, so as to determine a second satellite network that meets the RACH-free handover condition among the multiple candidate satellite networks.

[0142] As mentioned above, the reference signals of the multiple candidate satellite networks may also be SSB-RS and / or CSI-RS. The signal quality of the reference signal may be at least one of RSRP, RSRQ, SINR, and RSSI.

[0143] For example, the terminal device may 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 may be obtained. These second measurement results may be used to generate the first measurement report. In other words, if there are multiple target NTNs, such as NTN2, NTN3, etc., the terminal device reports the reference signal measurement results based on the multiple target NTNs.

[0144] Illustratively, the multiple second measurement results of the first measurement report can be used to determine whether a second satellite network exists that meets the RACH-free handover condition. For example, the second satellite network can be determined based on whether any one of the multiple CSI-RS measurement results meets the RACH-free handover condition. Another example is determining whether any one of the SSB-RS measurement results of one or more candidate satellite networks meets the RACH-free handover condition.

[0145] In some embodiments, satellite handover can support satellite switching without changing the PCI (no L3 mobility required). In the PCI-unchanged scenario, the terminal device can switch to a target satellite with the same cell configuration, except for satellite-specific information. For example, the terminal device can maintain its device-specific configuration, except for TA acquisition and DL / UL synchronization in the PCI-unchanged scenario. That is, the terminal device does not need to perform reconfiguration. Therefore, the PCI-unchanged scenario is a specific case of inter-satellite handover with the same gateway / gNB.

[0146] Optionally, if the first satellite network receives RACH-free switching information from a candidate satellite network containing the same PCI, the candidate satellite network may be used as a preferred target satellite network.

[0147] In certain handover scenarios, such as RACH-free handover, the quality of the reference signal from the second satellite network is crucial. For example, to ensure reliable initial UL transmission during RACH-free handover, the downlink signal quality of the second satellite network must be greater than or equal to a certain threshold. For another example, a RACH-free handover is triggered only when the downlink RSRP measured by the terminal device is greater than or equal to the RSRP threshold.

[0148] Exemplarily, the second measurement result corresponding to the second satellite network is the maximum value among the multiple second measurement results. For example, the first satellite network may select a satellite network with the largest RSRP from multiple candidate satellite networks as the second satellite network.

[0149] Exemplarily, the second measurement result corresponding to the second satellite network is a second measurement result among the multiple second measurement results that is greater than or equal to a second threshold. The second threshold may be set by the first satellite network. In some embodiments, the second threshold may be different for different signal quality parameters. In some embodiments, the second threshold may be determined based on parameters such as the actual communication environment and service type.

[0150] For example, when the first measurement report includes the RSRPs of the SSB-RSs of multiple candidate satellite networks, if the RSRP of a candidate satellite network is greater than or equal to a second threshold corresponding to the RSRP, the candidate satellite network is designated as the second satellite network. The first satellite network may, based on the measurement report of the terminal device, select RACH-free switching as the optimal switching method and switch to the candidate satellite network.

[0151] 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 determines whether to trigger RACH-free handover for the terminal device. RACH-free handover is triggered for the terminal device only when the downlink RSRP measured by the terminal device is greater than or equal to an RSRP threshold.

[0152] In some embodiments, the first satellite network may send a handover request to the second satellite network before sending the handover command, and may send the first handover command after receiving an acknowledgment of the request from the second satellite network. For example, after determining that a satellite network that meets the conditions exists and triggering a RACH-free handover, the first satellite network may send a RACH-free handover request to the second satellite network. The second satellite network may send a handover request acknowledgment (ACK) message to the first satellite network. Based on this acknowledgment, the first satellite network may send the first handover command to the terminal device.

[0153] Exemplarily, the handover request confirmation may also be referred to as a handover request response, answer information, etc. The handover request confirmation may be expressed as HANDOVER REQUEST ACKNOWLEDGE.

[0154] The handover request confirmation sent by the second satellite network may include various information to facilitate the first satellite network notifying the terminal device of the first handover command. For example, the handover request confirmation may include the UL grant determined by the second satellite network. In another example, the handover request confirmation may also include the SSB index and pre-assigned grant related to the terminal device's transmission in the second satellite network.

[0155] In some embodiments, the handover request confirmation may include information related to resource reservation, or information related to power factors when the terminal device switches access to the second satellite network, etc. The power-related information will be described in conjunction with FIG7 .

[0156] Exemplarily, 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 may indicate the first beam or SSB index associated with the first resource through the handover request confirmation.

[0157] The first satellite network may generate a first handover command according to the handover request confirmation of the second satellite network. The first handover command may include a variety of information.

[0158] In some embodiments, the first switching command includes one or more of the following information: an authorization pre-allocated by the second satellite network; a first resource pre-configured by the second satellite network; a beam index associated with the 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; the beam index associated with the specified signal quality reported within the coverage area received by the second satellite network; the average value of the access power of terminal devices other than the terminal device in the second satellite network; the maximum value of the access power of terminal devices other than the terminal device in the second satellite network.

[0159] Exemplarily, the authorization pre-allocated by the second satellite network and the pre-configured first resources are used for handover by the terminal device.

[0160] Exemplarily, 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.

[0161] Exemplarily, the maximum signal quality reported within the coverage area and its associated beam index may 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.

[0162] Optionally, the terminal device may select the signal quality reported by the second satellite network received from other terminal devices within the coverage area of ​​the second satellite network, and select the maximum signal quality and the associated beam as its access beam for accessing the second satellite network.

[0163] Exemplarily, the beam index associated with the specified signal quality reported within the coverage area may be the beam index of the signal corresponding to the specified signal quality parameter, which may be used by the terminal device to determine the optimal access beam.

[0164] Optionally, the designated signal quality may be determined based on the average signal quality and a specific reference quantity. For example, the designated signal quality may be the signal quality obtained by adding or subtracting the average signal quality from the specific reference quantity.

[0165] Optionally, the designated signal quality may be determined based on the maximum signal quality and a specific reference quantity. For example, the designated signal quality may be the signal quality obtained by subtracting the maximum signal quality from the specific reference quantity.

[0166] Optionally, a beam associated with the signal quality obtained by adding or subtracting a specific reference amount from the reported average signal quality is used as the access beam in the second satellite network.

[0167] Optionally, the signal quality may also be referred to as signal strength, and the signal quality may be represented by the aforementioned RSRP, RSRQ, RSSI, or at least one other parameter indicating signal quality.

[0168] For example, the average and maximum values ​​of the admission powers of the terminal devices other than the terminal device in the second satellite network may be used by the terminal device to determine the transmit power, which will be explained in detail below in conjunction with FIG.

[0169] For example, when the first switching command is a RACH-free switching 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 of the second satellite network relative to the terminal device based on the terminal device location information; maximum signal strength within the coverage area received by the second satellite network, such as RSRP, RSSI, etc.; average signal strength within the coverage area received by the second satellite network, such as RSRP, RSSI, etc.; average access receive power of other terminal devices allowed to access the second satellite network; maximum access receive power of other terminal devices allowed to access the second satellite network; time-related parameters of the second satellite network.

[0170] As shown in Figure 4, in certain handovers (e.g., RACH-free handovers), after determining the second satellite network to handover to, the terminal device can send information identifying the first beam to the second satellite network, enabling the second satellite network to more effectively reserve resources, thereby improving the success rate of the handover. When resource reservation is indicated by a UL grant, the UL grant can be allocated via RRC signaling and / or the PDCCH of the second satellite network for easy reception by the terminal device.

[0171] For ease of understanding, the following provides an exemplary description of two possible implementations shown in Figures 5 and 6. Figure 5 is a schematic flow chart of a terminal device sending first information to a second satellite network before receiving a first handover command. Figure 6 is a schematic flow chart of a terminal device performing RACH-free handover.

[0172] 5 , in step S510 , the terminal device sends a first measurement report to the first satellite network.

[0173] In step S520, the first satellite network makes a handover decision to determine the second satellite network.

[0174] In step S530, 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, generate and send the first information.

[0175] In step S540, the first satellite network sends a handover request to the second satellite network, wherein the handover request includes first information for the second satellite network to determine the first beam.

[0176] In step S550, the second satellite network sends a handover request confirmation to the first satellite network. The handover request confirmation includes second information for indicating the first beam to the terminal device.

[0177] In step S560, the first satellite network sends a first switching command to the terminal device.

[0178] In step S570, the terminal device sends an initial uplink transmission to the second satellite network.

[0179] In FIG5 , the first information sent by the terminal device is after the handover decision is made. 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 to facilitate the terminal device to determine the second satellite network.

[0180] 6 , in step S610 , the terminal device sends a measurement control and report to the first satellite network.

[0181] In step S620, the first satellite network makes a handover decision (HO decision).

[0182] In step S630, the first satellite network sends a handover request (HO request) to the second satellite network.

[0183] In step S640, the second satellite network sends a handover request acknowledgment (HO request ACK) to the first satellite network.

[0184] In step S650, the first satellite network sends RACH-less HO configuration information to the terminal device. The terminal device starts timers T304 and T430 in sequence.

[0185] In step S660, the terminal device sends an initial uplink transmission. The initial uplink transmission is sent using an available uplink grant (RRC, MAC, PHY). The initial uplink transmission includes sending an RRCReconfigurationComplete message.

[0186] In step S670, the terminal device receives an acknowledgment (RACH-less HO ACK) from the second satellite network, thereby completing the RACH-less handover. The second satellite network releases the pre-allocated UL grant. The terminal device stops timer T304.

[0187] The handover request confirmation in FIG6 may include the second information described above, so that the terminal device can determine the first beam or SSB associated with the reserved resources of the second satellite network.

[0188] In certain mobility scenarios, a terminal device may receive a handover command including a list of candidate satellite networks (candidate networks) and handover conditions, and autonomously perform 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 may be referred to as a "conditional handover (CHO)," and a handover command associated with a conditional handover may be referred to as a "conditional handover command." For conditional handover, the terminal device may autonomously select a target network from the candidate networks based on measurements of the candidate networks.

[0189] In NTN, if CHO is configured, the condition for the terminal device to perform satellite handover can be called the first condition. That is, satellite handover is performed when the first condition is met.

[0190] If RACH-less handover and CHO are configured, the first handover command needs to indicate multiple candidate satellite networks and multiple uplink grants. For example, the first handover command includes parameters of multiple candidate satellite networks, and the first resource in the first handover command includes multiple uplink grants. If the first condition is met, the terminal device can determine the second satellite network from the multiple candidate satellite networks and determine the uplink grant for the terminal device to perform handover from the multiple uplink grants.

[0191] Exemplarily, in configuring satellite handover with RACH-less handover and CHO, the first satellite network and the second satellite network need to indicate timing adjustment and optionally multiple pre-allocated grants.

[0192] Exemplarily, the first satellite network may further 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: a handover condition based on an SSB-RS associated with at least one candidate satellite network; a handover condition based on a CSI-RS associated with at least one candidate satellite network; measurement results / measurement information of at least one SSB-RS or CSI-RS; or at least one SSB-RS or CSI-RS associated with a contention-free random access resource.

[0193] For example, the first satellite network may receive RRC reconfiguration information from the terminal device. The RRC reconfiguration information may include a signal measurement result of at least one target satellite network, and at least one SSB-RS, at least one CSI-RS, an SSB-based CHO execution condition, and a CSI-RS-based CHO execution condition associated with performing CHO.

[0194] The above describes the introduction of RACH-free handover and CHO handover conditions in NTN, so that terminal equipment can autonomously perform satellite handover when the conditions are met.

[0195] The preceding text, in conjunction with Figure 4, describes an embodiment of a method for resolving the resource reservation problem. In a RACH-free handover process, since there is no RACH preamble transmission and random access response reception, the terminal device may set the initial transmission power to an inappropriate level due to an incorrectly estimated path loss. For example, when the terminal device receives information about the UL grant, the terminal device may fall into a logical deadlock, resulting in a handover failure. For example, the terminal device confirms the UL grant, but due to low transmission power, the network device cannot receive the uplink transmission, and the response message always fails.

[0196] In RACH-free handover, if the initial transmission power of the terminal device uplink transmission directly refers to the power control rules used for configuring the authorized physical uplink shared channel (PUSCH), problems such as path loss uncertainty and inapplicable power adjustment may occur.

[0197] For example, in RACH-free handovers, grants are pre-assigned or dynamically granted, and the path loss determination is unclear or inaccurate. In NTN systems, satellites are located at great heights above the ground and cover a large area. Inaccurate path loss estimation can significantly impact power. In certain scenarios, if the two satellites being handed over are of different types and have significantly different heights above the ground, the accuracy of the path loss estimation can also be affected.

[0198] For example, for power adjustment and power control adjustment of PUSCH, 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 transmit power are not applicable to RACH-free switching.

[0199] In summary, when RACH-free handover is introduced in the NTN scenario, how the terminal device determines the initial transmission power for uplink transmission in the pre-allocated resources to improve the success rate of the terminal device handover access becomes a problem that needs to be solved.

[0200] It should be noted that the above-mentioned problem of inappropriate transmit power due to uncertain path loss and inability to trigger power control adjustment through PRACH when introducing RACH-free switching in the NTN system is only an example. The embodiments of the present application can be used for any type of switching scenario where the path loss in the transmit power is uncertain or power adjustment cannot be triggered.

[0201] To address the aforementioned issues, embodiments of the present application propose another method for NTN satellite handover. Using this method, the first handover command can include power-related information within the coverage area of ​​the second satellite network and / or the relative position information between the network equipment corresponding to the second satellite network and the terminal device, allowing the terminal device to determine the first power for uplink transmission to the second satellite network. This first power factor takes into account the communication or location conditions of the second satellite network, helping to improve the accuracy of the first power and thus the success rate of handover.

[0202] For ease of understanding, another method proposed in an embodiment of the present application is described in detail below with reference to FIG7 . The method shown in FIG7 is executed by a terminal device. The method shown in FIG7 is also used for satellite handover from a first satellite network coverage area to a second satellite network coverage area. For the sake of brevity, the terminology explained in FIG4 will not be repeated in FIG7 .

[0203] Referring to FIG. 7 , in step S710 , a first switching command is received.

[0204] The first handover command received by the terminal device comes from the first satellite network. The first satellite network can confirm and determine the first handover command according to the handover request sent by the second satellite network.

[0205] The first handover command may be used to determine a first power for uplink transmission by the terminal device to the second satellite network. In some embodiments, the first handover command may be a RACH-free handover command. In some embodiments, the first handover command may be a handover command for other handover modes without a random access response.

[0206] The uplink transmission performed by the terminal device to the second satellite network may be the initial uplink transmission described above, or may be other uplink transmission sent by the terminal device to the second satellite network. Exemplarily, the uplink transmission is PUSCH transmission.

[0207] The uplink transmission may be transmitted on the first resource preconfigured by the second satellite network. In some embodiments, for a PUSCH transmission without reserved resources in a RACH handover, the SSB may be associated with the initial PUSCH transmission. That is, for a pre-allocated initial PUSCH transmission, the SSB may be determined before the PUSCH resources are determined.

[0208] The first power can be the transmit power of the terminal device's initial uplink transmission, or it can be the initial transmit power used by the terminal device to communicate with the second satellite network. As previously mentioned, in an NTN, if a terminal device does not perform a random access procedure when performing a 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 can include relevant information used by the terminal device to determine the initial transmit power, thereby improving the accuracy of path loss estimation and / or the rationality of power adjustment.

[0209] To improve the accuracy of the first power, the first handover command may include 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. Information related to communication parameters within the coverage area of ​​the second satellite network may be included in the handover request confirmation sent by the second satellite network.

[0210] The power-related information within the coverage area of ​​the second satellite network can represent power parameters for communication between the second satellite network and terminal devices within the coverage area. When the terminal device determines the first power based on these power parameters, it can obtain a power value more suitable for accessing the second satellite network, thereby improving the access success rate.

[0211] In some embodiments, the power-related information within the coverage area of ​​the second satellite network may include one or more of the following parameters: the average value of the signal quality of some or all uplink beams accessed within the area; the maximum value of the signal quality of some or all uplink beams accessed within the area; the transmission power of random access uplink channels sent by at least some terminal devices that have accessed within the area; the average value of the access power of terminal devices other than the terminal devices in the second satellite network; the maximum value of the access 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.

[0212] Exemplarily, the power-related information may also include signal quality of a beam associated with RACH-free switching.

[0213] Exemplarily, the signal quality may be one or more of the RSRP, RSRQ, and RSSI mentioned above.

[0214] Part or all of the uplink beams accessed within the coverage area of ​​the second satellite network refer to part or all of the uplink beams within the coverage area received by the second satellite network. In some embodiments, part of the uplink beams may be uplink beams of other terminal devices located close to the terminal device.

[0215] For example, when the handover request confirmation includes an average value of signal strengths (e.g., RSRP) of some or all uplink beams within the coverage area received by the second satellite network, the terminal device may obtain this average value through the first handover command. The terminal device may estimate, based on this average value, the transmit power required to achieve this intensity at its current location, and use this as the first power value for the terminal device to switch to the second satellite network.

[0216] For example, when the handover request confirmation includes the maximum 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 the first handover command. Based on this maximum value, the terminal device can estimate the transmit power required to achieve this intensity at its current location, and use this as the first power for handing over to the second satellite network. When the terminal device determines the first power based on the maximum value, the problem of insufficient transmit power and inability to receive a response can be effectively resolved.

[0217] The beam associated with RACH-free handover within the coverage area of ​​the second satellite network refers to the beam associated with RACH-free handover reserved within the coverage area received by the second satellite network. In some embodiments, these associated beams can be SSB beams. For example, the path loss reference signal used for PUSCH transmission can select the reference signal of the SSB used to determine the reserved PUSCH resources.

[0218] For example, when the handover request confirmation includes the signal strength (e.g., RSRP) of the beam reserved for RACH-free handover within the coverage area received by the second satellite network, the terminal device can obtain this value through the first handover command. The terminal device can estimate the transmit power required to achieve this strength at its current location based on this maximum value, and use this as the first power value for the terminal device to hand over to the second satellite network.

[0219] For example, for an initial PUSCH transmission based on a dynamic grant (DG), the second satellite network may directly indicate the SSB via the PDCCH. Since there is no random access procedure, for power control of the initial PUSCH transmission, the path loss reference may be the SSB associated with the initial PUSCH transmission.

[0220] The transmission power of the random access uplink channel sent by at least some terminal devices that have been connected within the coverage area of ​​the second satellite network refers to the power received by the second satellite network through the physical random access channel (PRACH) within the coverage area. In some embodiments, these parameters can be determined based on the initial nominal power of PUSCH. The initial nominal power of PUSCH transmission can be configured in RRC in the same way as traditional. In some embodiments, the initial nominal power of PUSCH transmission may not be configured, and these parameters can be determined as the initial target received power of PRACH in the second satellite network. Although PRACH is not initiated by the terminal device performing RACH-free switching, it can be read from the system information block (SIB) of the second satellite network.

[0221] Exemplarily, the terminal device may read the PRACH initial target received power of other terminal devices in the SIB1 of the second satellite network as a reference for determining the first power.

[0222] For example, in RACH-free switching, since there is no random access process, the transmit power of the random access uplink channel can be the transmit power of message A (msgA) sent by at least some terminal devices, or the transmit power of message 3 (msg3) sent by at least some terminal devices. In other words, 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 benchmark can be the average or maximum value of the transmit power of message A sent by some terminal devices. For another example, the benchmark can be the average or maximum value of the transmit power of message A sent by all terminal devices.

[0223] The average or maximum value of the access power of terminal devices other than the terminal device in the second satellite network refers to the average or maximum value of the access power allowed to other terminal devices by the second satellite network. For terminal devices, parameters related to the access power can serve as a reference for the first power. For example, when the terminal device's service requires timely access to the second satellite network, the first power can be equal to or close to the maximum value of the access power. In another example, the first power can be equal to the average value for initial uplink transmission.

[0224] Illustratively, the terminal devices other than the terminal device may be some of the terminal devices in the second satellite network, or may be all of the terminal devices, which is not limited here.

[0225] Exemplarily, some terminal devices may be other terminal devices that are geographically close to the terminal device.

[0226] The average path loss or maximum path loss within the coverage area of ​​the second satellite network refers to the average value or maximum value of the path loss for communication between the network device corresponding to the second satellite network and other terminal devices, and both can be used to determine the path loss in the first power.

[0227] 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 (e.g., 80%) of the maximum output power. Exemplarily, the first power is determined based on the power-related information in the first switching 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 the average value.

[0228] In step S720, a first power for uplink transmission to the second satellite network is determined based on the first handover command. The above describes various possible implementations for determining the first power in conjunction with the information in the first handover command, and will not be repeated here. The following briefly describes how to calculate the PUSCH transmission power.

[0229] The first handover command may further include relative position information between a second satellite corresponding to the second satellite network and the terminal device, so as to facilitate determining a path loss compensation factor for the terminal device in the second satellite network. The second satellite is a satellite corresponding to the second satellite network, and the first satellite is a satellite corresponding to the first satellite network.

[0230] The path loss experienced by a terminal device in the first satellite network and the second satellite network is different, 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 for the terminal device in the second satellite network can be referred to as the second path loss compensation factor.

[0231] In some embodiments, the second path loss compensation factor may be carried in a 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 may be directly sent to the terminal device via the first handover command.

[0232] In some embodiments, the relative position information may include the distance between the terminal device and the second satellite. Based on the distance parameter, the path loss may be estimated. The distance may be determined by the position coordinate information of the terminal device and the position coordinate information of the second satellite. Exemplarily, the position coordinate information of the terminal device may be obtained via GNSS position information or other means. The first satellite network may 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 may be determined via satellite ephemeris information (ephemerisInfo).

[0233] In some embodiments, the relative position information may include a bearing angle between the terminal device and the second satellite. The bearing angle may also be referred to as an azimuth. The bearing angle may be the angle between a line connecting the terminal device and the satellite and a perpendicular line between the satellite and the ground, that is, the bearing angle between the terminal device and the satellite perpendicular to the ground. The bearing angle may also be determined based on the position of the terminal device and the position of the second satellite.

[0234] In some embodiments, the relationship between the path loss between the terminal device and the first satellite network and the second satellite network may be used to determine the second path loss compensation factor.

[0235] Exemplarily, the path loss compensation factor of the terminal device in the second satellite network can be determined by the direction angle of the terminal device in the first satellite network and the direction 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:

[0236] Wherein, δ1 represents the direction angle between the terminal device and the first satellite corresponding to the first satellite network, and δ2 represents the direction angle between the terminal device and the second satellite.

[0237] For ease of understanding, the following schematically illustrates how the second path loss compensation factor is determined, with reference to FIG8 . Referring to FIG8 , satellite 810 is a first satellite corresponding to a first satellite network, and satellite 820 is a second satellite corresponding to a second satellite network. Terminal device 830 performs a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network.

[0238] As shown in Figure 8 , the distance between terminal device 830 and satellite 810 is D1, and the direction angle is δ1. The distance between terminal device 830 and satellite 820 is D2, and the direction angle is δ2. The first satellite network and the second satellite network can obtain the direction angles δ1 and δ2 between terminal device 830 and satellites 810 and 820 perpendicular to the ground at this time using the position coordinate information of terminal device 830.

[0239] The above describes a variety of methods for determining the second path loss compensation factor K. According to 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 in the uplink bandwidth b of the carrier f of the serving cell c is PUSCH,b,f,c It can be determined according to the following formula:

[0240] Among them, i represents the transmission opportunity, j represents the index of the parameter set configuration, and q d represents the index of the reference signal, l represents the index of the power control adjustment state, μ is related to the subcarrier spacing, P CMAX,f,c (i) represents the maximum output power of the terminal equipment in the second satellite network, Indicates the current transmit power of the terminal device in the first satellite network, represents the uplink resource bandwidth, α b,f,c (j) represents the path loss compensation factor of the terminal device in 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.

[0241] Optionally, It can be the number of resource blocks.

[0242] Optionally, μ may be a subcarrier spacing configuration supported by the protocol, which may enable adjustment of bandwidth resources under different subcarrier spacing configurations, thereby enabling corresponding power adjustment.

[0243] As mentioned above, α b,f,c (j) may be a first path loss compensation factor estimated by the current terminal device in the first satellite network.

[0244] Optionally, PL b,f,c (q d ) may be a downlink path loss obtained by the terminal device by measuring a downlink reference signal. This parameter may be determined using an evaluation result of the first satellite network, or based on information from the second satellite network in the first handover command sent by the first satellite network.

[0245] Optionally, the terminal device calculates PL b,f,c (q d ), the RS resources from the SS / PBCH block can be used. The index of the 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).

[0246] Optionally, the terminal device calculates PL b,f,c (q d ), RS resources from the SS / PBCH block can be used. The index of the SS / PBCH block corresponding to the RS resource is the same as the index of the SS / PBCH block used by the terminal device to monitor the PDCCH dynamically scheduled UL grant. The UL grant dynamically scheduled by the PDCCH is used for initial transmission.

[0247] Δ TF,b,c,f (i) It can be determined by the value of the preamble power ramp-up counter (PREAMBLE_POWER_RAMPING_COUNTER).

[0248] Optionally, f b,f,c (i, l) may represent the PUSCH power control adjustment state for uplink bandwidth part b corresponding to carrier f of the first satellite network in PUSCH transmission opportunity 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 may also be jointly encoded with other TPC commands in DCI format 2_2, where the cyclic redundancy check (CRC) is scrambled by the TPC-PUSCH-RNTI.

[0249] Optionally, The value of the current transmit power of the terminal device is provided. If the terminal device is in an RRC connected state, the handover request confirmation message from the second satellite network to the first satellite network may include ConfiguredGrantConfig information sent by the second satellite network to the terminal device. This information may include resources, beam indexes, and average or maximum path loss parameters within the second satellite network.

[0250] The above describes a method for determining the first power based on the second path loss compensation factor K. As mentioned above, the first handover command may be a RACH-free handover command. When the satellite handover is RACH-free, the preamble power increase counter described above may not be able to determine the power adjustment amount of the second satellite network. The power increase in the preamble power increase 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, parameters in the second satellite network cannot be associated with this counter.

[0251] To address this issue, a new power adjustment counter P can be used. Power adjustment counter P can be a counter corresponding to a non-RACH and can be used to determine the power adjustment amount in the first power. In some embodiments, the value of power adjustment counter P can be related to parameters used by the terminal device to access the first satellite network. In some embodiments, the value of power adjustment counter P can be related to the number of random accesses performed by the terminal device. For example, the value of power adjustment counter P is the number of accesses performed by the terminal device to establish a connection with the first satellite network.

[0252] In some embodiments, the power adjustment amount in the first power may also be determined according to a power adjustment factor. The power adjustment factor is, for example, N, where the value of N is a positive integer greater than 1.

[0253] For example, the power adjustment factor N can be determined according to the service type of the terminal device. In other words, N is related to the service type. For example, the higher the quality of service (QoS) requirement, the larger the value of N can be.

[0254] For example, during a handover, the power adjustment used on the first satellite network cannot be retained. To ensure a smooth handover of the terminal device to the second satellite network, the transmit power must be relatively high. While this may cause some interference to other nearby terminal devices, it can still ensure successful access. Once the terminal device transmits a successful handover message, indicating that a communication link has been established with the second satellite network, its transmit power will decrease. Even if it does not receive a TPC adjustment command in the PDCCH, the terminal device will reduce its transmit power based on the new power adjustment counter.

[0255] The above describes a method for determining the power adjustment factor N. According to 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 in the uplink bandwidth b of the carrier f of the serving cell c is PUSCH,b,f,c It can be determined according to the following formula:

[0256] Wherein, N represents the power adjustment factor, and N>1. Other parameters have been introduced above and will not be repeated here.

[0257] Optionally, the first power of the terminal device may comprehensively consider the path loss and the power adjustment amount. For example, the first power P of the terminal device for uplink transmission in the uplink bandwidth b of the carrier f of the serving cell c is PUSCH,b,f,c It can be determined according to the following formula:

[0258] Wherein, K represents the second path loss compensation factor, and N represents the power adjustment factor.

[0259] The method embodiment of the present application is described in detail above with reference to Figures 1 to 8 . The device embodiment of the present application is described in detail below with reference to Figures 9 to 15 . It should be understood that the description of the device embodiment corresponds to the description of the method embodiment. Therefore, for portions not described in detail, reference can be made to the aforementioned method embodiment.

[0260] FIG9 is a schematic block diagram of a terminal device according to an embodiment of the present application. The terminal device 900 may be any of the terminal devices described above. The terminal device 900 shown in FIG9 includes a sending unit 910 and a first receiving unit 920.

[0261] Sending unit 910 can be used to send first information, where the first information is used by the second satellite network to determine a first beam corresponding to the terminal device, where the first beam includes one or more beams; wherein the first beam is related to the first resource and / or second resource preconfigured by the second satellite network for satellite switching.

[0262] The first receiving unit 920 is configured to receive a first handover command, where the first handover command is used to instruct the terminal device to perform satellite handover from the first satellite network coverage area to the second satellite network coverage area.

[0263] Optionally, the first handover command includes one or more of the following information: a grant pre-allocated by 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; a maximum signal quality within the coverage area received by the second satellite network; an average signal quality within the coverage area received by the second satellite network; an average admission power of terminal devices other than the terminal device in the second satellite network; and a maximum admission power of terminal devices other than the terminal device in the second satellite network. Optionally, the first information includes multiple first measurement results of the reference signals of multiple beams of the second satellite network measured by the terminal device, where the multiple first measurement results are used to determine the first beam.

[0264] Optionally, the first measurement result corresponding to the first beam is a maximum value among multiple first measurement results, or the largest M values ​​among the multiple first measurement results.

[0265] Optionally, the first measurement result corresponding to the first beam is greater than a first threshold.

[0266] Optionally, the first resource is a reserved resource for satellite switching, and the second resource is a scheduled uplink resource, and the uplink resource is used for the terminal device to perform satellite switching.

[0267] Optionally, the first receiving unit 920 is also used to receive second information after sending the first information, where the second information is 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 switching command.

[0268] Optionally, the first beam is indicated by an identifier of a reference signal associated with the first beam.

[0269] Optionally, the satellite switching is RACH-free switching, and the second satellite network is a satellite network that meets the RACH-free switching condition. The sending unit 910 is further used to send a first measurement report before sending the first information, and the first measurement report is used by the first satellite network to determine the second satellite network among multiple candidate satellite networks; wherein the first measurement report includes multiple second measurement results of the terminal device measuring the reference signals of the multiple candidate satellite networks.

[0270] Optionally, the second measurement result corresponding to the second satellite network is a maximum value among multiple second measurement results, or a second measurement result among the multiple second measurement results that is greater than or equal to a second threshold.

[0271] Optionally, the reference signal includes SSB-RS and / or CSI-RS.

[0272] Optionally, the first beam is also used to carry one or more synchronization signal blocks for the terminal device to perform satellite switching, and the index of the one or more synchronization signal blocks is associated with the first resource.

[0273] Optionally, the first handover command is a RACH-free handover command.

[0274] Optionally, satellite switching is performed when a first condition is met, the first switching command includes parameters of multiple candidate satellite networks, the first resource includes multiple uplink authorizations, and the terminal device 900 also includes a first determination unit, which can be used to determine the second satellite network among the multiple candidate satellite networks; the second determination unit can be used to determine the uplink authorization for the terminal device to perform switching among the multiple uplink authorizations.

[0275] Optionally, the sending unit 910 is further used to send third information to the first satellite network, where the third information is used to indicate the first condition; wherein the third information includes one or more of the following information: a switching condition based on the association of SSB-RS with at least one candidate satellite network; a switching condition 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.

[0276] FIG10 is a schematic block diagram of a network device according to an embodiment of the present application. The network device 1000 may be any network device corresponding to the first satellite network described above. The network device 1000 shown in FIG10 includes a receiving unit 1010, a first sending unit 1020, and a second sending unit 1030.

[0277] The receiving unit 1010 may be configured to receive first information sent by a terminal device.

[0278] The first sending unit 1020 can be used to send 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; wherein the first beam is related to the first resource and / or second resource preconfigured by the second satellite network for satellite switching.

[0279] The second sending unit 1030 may be configured to send a first switching command to the terminal device, where the first switching command is used to instruct the terminal device to perform satellite switching from the first satellite network coverage area to the second satellite network coverage area.

[0280] Optionally, the first switching command includes one or more of the following information: an authorization pre-allocated by 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 value of the signal quality within the coverage area received by the second satellite network; the average value of the signal quality within the coverage area received by the second satellite network; the average value of the access power of terminal devices other than the terminal device in the second satellite network; and the maximum value of the access power of terminal devices other than the terminal device in the second satellite network.

[0281] Optionally, the first resource is a reserved resource for satellite switching, and the second resource is a scheduled uplink resource, and the uplink resource is used for the terminal device to perform satellite switching.

[0282] Optionally, the receiving unit 1010 is further used 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 used to send the second information to the terminal device, where the second information is used to indicate the first beam.

[0283] Optionally, the satellite switching is RACH-free switching, and the second satellite network is a satellite network that meets the RACH-free switching condition. The receiving unit 1010 is further used 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; wherein the first measurement report includes multiple second measurement results of the terminal device measuring the reference signals of the multiple candidate satellite networks.

[0284] Optionally, the second measurement result corresponding to the second satellite network is a maximum value among multiple second measurement results, or a second measurement result among the multiple second measurement results that is greater than or equal to a second threshold.

[0285] Optionally, the reference signal includes SSB-RS and / or CSI-RS.

[0286] Optionally, the first handover command is a RACH-free handover command.

[0287] Optionally, satellite switching is performed when a first condition is met, and the first switching command includes parameters of multiple candidate satellite networks. The receiving unit 1010 is also used to receive third information sent by the terminal device, and the third information is used to indicate the first condition; wherein the third information includes one or more of the following information: a switching condition based on SSB-RS associated with at least one candidate satellite network; a switching condition based on CSI-RS associated 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 non-contention random access resource.

[0288] FIG11 is a schematic block diagram of another network device according to an embodiment of the present application. The network device 1100 may be any network device corresponding to the second satellite network described above. The network device 1100 shown in FIG11 includes a receiving unit 1110 and a first sending unit 1120.

[0289] Receiving unit 1110 can be used to receive first information sent by the first satellite network, where the first information is used to determine a first beam corresponding to the second satellite network and the terminal device, where the first beam includes one or more beams; wherein the first beam is related to the first resource and / or second resource preconfigured by the second satellite network for satellite switching.

[0290] The first sending unit 1120 may be configured to send a handover request confirmation to the first satellite network based on 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.

[0291] Optionally, the first switching command includes one or more of the following information: an authorization pre-allocated by 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 value of the signal quality within the coverage area received by the second satellite network; the average value of the signal quality within the coverage area received by the second satellite network; the average value of the access power of terminal devices other than the terminal device in the second satellite network; and the maximum value of the access power of terminal devices other than the terminal device in the second satellite network.

[0292] Optionally, the first information includes multiple first measurement results of the terminal device measuring the reference signals of multiple beams of the second satellite network, and the multiple first measurement results are used to determine the first beam.

[0293] Optionally, the first measurement result corresponding to the first beam is a maximum value among multiple first measurement results, or the largest M values ​​among the multiple first measurement results.

[0294] Optionally, the first measurement result corresponding to the first beam is greater than a first threshold.

[0295] Optionally, the first resource is a reserved resource for satellite switching, and the second resource is a scheduled uplink resource, and the uplink resource is used for the terminal device to perform satellite switching.

[0296] Optionally, after receiving the first information, the first sending unit 1120 is also used to send second information to the first satellite network, where the second information is used to indicate the first beam; the network device 1100 also includes a second sending unit, which can be used to send a downlink channel according to the first beam after sending a switching request confirmation to the first satellite network.

[0297] Optionally, the first beam is indicated by an identifier of a reference signal associated with the first beam.

[0298] Optionally, the reference signal includes SSB-RS and / or CSI-RS.

[0299] Optionally, the first beam is also used to carry one or more synchronization signal blocks for the terminal device to perform satellite switching, and the index of the one or more synchronization signal blocks is associated with the first resource.

[0300] Optionally, the first handover command is a RACH-free handover command.

[0301] FIG12 is a schematic block diagram of another terminal device according to an embodiment of the present application. The terminal device 1200 may be any of the terminal devices described above. The terminal device 1200 shown in FIG12 includes a receiving unit 1210 and a determining unit 1220.

[0302] Receiving unit 1210 can be used to receive a first switching command, where the first switching command is used to instruct the terminal device to perform satellite switching from the first satellite network coverage area to the second satellite network coverage area. The first switching command includes power-related information within the second satellite network coverage area, and / or relative position information between the second satellite corresponding to the second satellite network and the terminal device.

[0303] The determining unit 1220 may be configured to determine a first power for uplink transmission to the second satellite network according to the first switching command.

[0304] Optionally, the power-related information within the coverage area of ​​the second satellite network includes one or more of the following parameters: the average value of the signal quality of some or all uplink beams accessed within the area; the maximum value of the signal quality of some or all uplink beams accessed within the area; the transmission power of random access uplink channels sent by at least some terminal devices that have accessed within the area; the average value of the access power of terminal devices other than the terminal devices in the second satellite network; the maximum value of the access 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.

[0305] Optionally, the first power is determined according to power-related information and a maximum output power of the terminal device.

[0306] Optionally, the signal quality is one or more of the following parameters: RSRP, RSRQ, RSSI.

[0307] Optionally, the transmission power of random access channels sent by at least some terminal devices that have accessed the area includes one or more of the following: the transmission power of message A sent by at least some terminal devices; the transmission power of message 3 sent by at least some terminal devices.

[0308] Optionally, the relative position information is used to determine a 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 information: the distance between the terminal device and the second satellite; and the direction angle between the terminal device and the second satellite.

[0309] Optionally, the path loss compensation factor is determined according to the direction angle between the terminal device and the second satellite, and the path loss compensation factor K is determined according to the following formula:

[0310] Wherein, δ1 represents the direction angle between the terminal device and the first satellite corresponding to the first satellite network, and δ2 represents the direction angle between the terminal device and the second satellite.

[0311] Optionally, the first power P of the terminal device for uplink transmission in the uplink bandwidth b of the carrier f of the serving cell c isPUSCH,b,f,c Determined according to the following formula:

[0312] Among them, i represents the transmission opportunity, j represents the index of the parameter set configuration, and q d represents the index of the reference signal, l represents the index of the power control adjustment state, μ is related to the subcarrier spacing, P CMAX,f,c (i) represents the maximum output power of the terminal equipment in the second satellite network, Indicates the current transmit power of the terminal device in the first satellite network, represents the uplink resource bandwidth, α b,f,c (j) represents the path loss compensation factor of the terminal device in 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,d,c (i, l) represents the power control adjustment state.

[0313] Optionally, the first switching command is a RACH-free switching command, and the power adjustment amount in the first power is determined according to a RACH-free power adjustment counter, and the value of the power adjustment counter is related to parameters for the terminal device to access the first satellite network.

[0314] Optionally, the value of the power adjustment counter is the number of access times by which the terminal device establishes a connection with the first satellite network.

[0315] Optionally, the power adjustment amount is further determined according to a power adjustment factor, and the power adjustment factor is determined according to a service type of the terminal device.

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

[0317] Wherein, N represents the power adjustment factor, and N>1.

[0318] Optionally, the first power P of the terminal device for uplink transmission in the uplink bandwidth b of the carrier f of the serving cell c is PUSCH,b,f,c Determined according to the following formula:

[0319] Where K represents the path loss compensation factor, and N represents the power adjustment factor.

[0320] FIG13 is a schematic block diagram of another network device according to an embodiment of the present application. The network device 1300 may be any network device corresponding to the first satellite network described above. The network device 1300 shown in FIG13 includes a determining unit 1310 and a sending unit 1310.

[0321] Determination unit 1310 may be configured to confirm and determine a first switching command based on a switching request sent by the second satellite network. The first switching command is used to instruct the terminal device to perform a satellite switching from the first satellite network coverage area to the second satellite network coverage area. The first switching command includes power-related information within the second satellite network coverage area, and / or relative position information between the second satellite corresponding to the second satellite network and the terminal device.

[0322] The sending unit 1320 may be configured to send a first switching command to the terminal device, where the first switching command is used by the terminal device to determine a first power for uplink transmission to the second satellite network.

[0323] Optionally, the power-related information within the coverage area of ​​the second satellite network includes one or more of the following parameters: the average value of the signal quality of some or all uplink beams accessed within the area; the maximum value of the signal quality of some or all uplink beams accessed within the area; the transmission power of random access uplink channels sent by at least some terminal devices that have accessed within the area; the average value of the access power of terminal devices other than the terminal devices in the second satellite network; the maximum value of the access 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.

[0324] Optionally, the first power is determined according to power-related information and a maximum output power of the terminal device.

[0325] Optionally, the signal quality is one or more of the following parameters: RSRP, RSRQ, RSSI.

[0326] Optionally, the transmission power of the random access uplink channel sent by at least some of the terminal devices that have accessed the area includes one or more of the following: the transmission power of message A sent by at least some of the terminal devices; the transmission power of message 3 sent by at least some of the terminal devices.

[0327] Optionally, the relative position information is used to determine a 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 information: the distance between the terminal device and the second satellite; and the direction angle between the terminal device and the second satellite.

[0328] Optionally, the path loss compensation factor is determined according to the direction angle between the terminal device and the second satellite, and the path loss compensation factor K is determined according to the following formula:

[0329] Wherein, δ1 represents the direction angle between the terminal device and the first satellite corresponding to the first satellite network, and δ2 represents the direction angle between the terminal device and the second satellite.

[0330] Optionally, the first power P of the terminal device for uplink transmission in the uplink bandwidth b of the carrier f of the serving cell c is PUSCH,b,f,c Determined according to the following formula:

[0331] Among them, i represents the transmission opportunity, j represents the index of the parameter set configuration, and q d represents the index of the reference signal, l represents the index of the power control adjustment state, μ is related to the subcarrier spacing, P CMAX,f,c (i) represents the maximum output power of the terminal equipment in the second satellite network, Indicates the current transmit power of the terminal device in the first satellite network, represents the uplink resource bandwidth, α b,f,c (j) represents the path loss compensation factor of the terminal device in 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.

[0332] Optionally, the first switching command is a RACH-free switching command, and the power adjustment amount in the first power is determined according to a RACH-free power adjustment counter, and the value of the power adjustment counter is related to parameters for the terminal device to access the first satellite network.

[0333] Optionally, the value of the power adjustment counter is the number of access times by which the terminal device establishes a connection with the first satellite network.

[0334] Optionally, the power adjustment amount is further determined according to a power adjustment factor, and the power adjustment factor is determined according to a service type of the terminal device.

[0335] Optionally, the first power P of the terminal device for uplink transmission in the uplink bandwidth b of the carrier f of the serving cell c is PUSCH,b,f,c Determined according to the following formula:

[0336] Wherein, N represents the power adjustment factor, and N>1.

[0337] Optionally, the first power P of the terminal device for uplink transmission in the uplink bandwidth b of the carrier f of the serving cell c is PUSCH,b,f,c Determined according to the following formula:

[0338] Where K represents the path loss compensation factor, and N represents the power adjustment factor.

[0339] FIG14 is a schematic block diagram of another network device according to an embodiment of the present application. The network device 1400 may be any network device corresponding to the second satellite network described above. The network device 1400 shown in FIG14 includes a sending unit 1410.

[0340] The sending unit 1410 may be configured to send a handover request confirmation to the first satellite network, where the handover request confirmation is used by the first satellite network to determine a first handover command, where the first handover command is used to instruct the terminal device to perform a satellite handover from an area covered by the first satellite network to an area covered by the second satellite network;

[0341] The first switching 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 switching command is used by the terminal device to determine the first power for uplink transmission to the second satellite network.

[0342] Optionally, the power-related information within the coverage area of ​​the second satellite network includes one or more of the following parameters: the average value of the signal quality of some or all uplink beams accessed within the area; the maximum value of the signal quality of some or all uplink beams accessed within the area; the transmission power of random access uplink channels sent by at least some terminal devices that have accessed within the area; the average value of the access power of terminal devices other than the terminal devices in the second satellite network; the maximum value of the access 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.

[0343] Optionally, the first power is determined according to power-related information and a maximum output power of the terminal device.

[0344] Optionally, the signal quality is one or more of the following parameters: RSRP, RSRQ, RSSI.

[0345] Optionally, the transmission power of the random access uplink channel sent by at least some of the terminal devices that have accessed the area includes one or more of the following: the transmission power of message A sent by at least some of the terminal devices; the transmission power of message 3 sent by at least some of the terminal devices.

[0346] Optionally, the relative position information is used to determine a 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 information: the distance between the terminal device and the second satellite; and the direction angle between the terminal device and the second satellite.

[0347] Optionally, the path loss compensation factor is determined according to the direction angle between the terminal device and the second satellite, and the path loss compensation factor K is determined according to the following formula:

[0348] Wherein, δ1 represents the direction angle between the terminal device and the first satellite corresponding to the first satellite network, and δ2 represents the direction angle between the terminal device and the second satellite.

[0349] Optionally, the first power P of the terminal device for uplink transmission in the uplink bandwidth b of the carrier f of the serving cell c is PUSCH,b,f,c Determined according to the following formula:

[0350] Among them, i represents the transmission opportunity, j represents the index of the parameter set configuration, and q d represents the index of the reference signal, l represents the index of the power control adjustment state, μ is related to the subcarrier spacing, P CMAX,f,c (i) represents the maximum output power of the terminal equipment in the second satellite network, Indicates the current transmit power of the terminal device in the first satellite network, represents the uplink resource bandwidth, α b,f,c (j) represents the path loss compensation factor of the terminal device in 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.

[0351] Optionally, the first switching command is a RACH-free switching command, and the power adjustment amount in the first power is determined according to a RACH-free power adjustment counter, and the value of the power adjustment counter is related to parameters for the terminal device to access the first satellite network.

[0352] Optionally, the value of the power adjustment counter is the number of access times by which the terminal device establishes a connection with the first satellite network.

[0353] Optionally, the power adjustment amount is further determined according to a power adjustment factor, and the power adjustment factor is determined according to a service type of the terminal device.

[0354] Optionally, the first power P of the terminal device for uplink transmission in the uplink bandwidth b of the carrier f of the serving cell c is PUSCH,b,f,c Determined according to the following formula:

[0355] Wherein, N represents the power adjustment factor, and N>1.

[0356] Optionally, the first power P of the terminal device for uplink transmission in the uplink bandwidth b of the carrier f of the serving cell c is PUSCH,b,f,c Determined according to the following formula:

[0357] Where K represents the path loss compensation factor, and N represents the power adjustment factor.

[0358] Figure 15 shows a schematic block diagram of a communication device according to an embodiment of the present application. The dashed lines in Figure 15 indicate that the unit or module is optional. Apparatus 1500 may be used to implement the method described in the above method embodiment. Apparatus 1500 may be a chip, a terminal device, or a network device.

[0359] The device 1500 may include one or more processors 1510. The processor 1510 may support the device 1500 to implement the method described in the method embodiment above. 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 another general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0360] The apparatus 1500 may further include one or more memories 1520. The memories 1520 store programs that can be executed by the processor 1510, causing the processor 1510 to perform the methods described in the above method embodiments. The memories 1520 may be independent of the processor 1510 or integrated into the processor 1510.

[0361] The apparatus 1500 may further include a transceiver 1530. The processor 1510 may communicate with other devices or chips via the transceiver 1530. For example, the processor 1510 may transmit and receive data with other devices or chips via the transceiver 1530.

[0362] The present application also provides a computer-readable storage medium for storing a program. The computer-readable storage medium can be applied to a terminal device or network device provided in the present application, and the program enables a computer to execute the method performed by the terminal device or network device in each embodiment of the present application.

[0363] The computer-readable storage medium may be any available medium that can be read by a computer or a data storage device such as a server or data center that includes one or more available media. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, or a magnetic tape), an optical medium (e.g., a digital versatile disc (DVD)), or a semiconductor medium (e.g., a solid state drive (SSD)).

[0364] The present application also provides a computer program product. The computer program product includes a program. The computer program product can be applied to a terminal device or network device provided in the present application, and the program causes a computer to execute the method performed by the terminal or network device in each embodiment of the present application.

[0365] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of 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, the process or function described in the embodiment of the present application is generated in whole or in part. 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 computer-readable storage medium. For example, the computer instructions can be transmitted from a website, a computer, a server or a data center via a wired

[0366] The data is transmitted to another website, computer, server or data center by means of (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.).

[0367] The present application also provides a computer program that can be applied to a terminal device or network device provided in the present application, and enables a computer to execute the method performed by the terminal or network device in each embodiment of the present application.

[0368] The terms "system" and "network" in this application may be used interchangeably. In addition, the terms used in this application are only used to explain the specific embodiments of this application and are not intended to limit this application. The terms "first," "second," "third," and "fourth" in the specification and claims of this application and the accompanying drawings are used to distinguish different objects rather than to describe a specific order. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions.

[0369] In the embodiments of this application, the term "indication" may refer to a direct indication, an indirect indication, or an indication of an association. For example, "A indicates B" may refer to a direct indication of B, e.g., B can obtain information through A; it may refer to an indirect indication of B, e.g., A indicates C, e.g., B can obtain information through C; or it may refer to an association between A and B.

[0370] In the embodiments of the present application, the term "corresponding" may indicate a direct or indirect correspondence between the two, or an association relationship between the two, or a relationship between indication and indication, configuration and configuration, etc.

[0371] In the embodiments of the present application, "pre-definition" or "pre-configuration" may be implemented by pre-storing corresponding codes, tables, or other methods that can be used to indicate relevant information in a device (e.g., including a terminal device and a network device). The present application does not limit the specific implementation method. For example, pre-definition may refer to a definition in a protocol.

[0372] In the embodiments of the present application, the "protocol" may refer to a standard protocol in the communication field, for example, it may include an LTE protocol, a NR protocol, and related protocols used in future communication systems, and this application does not limit this.

[0373] In the embodiments of the present application, determining B based on A does not mean determining B only based on A. B can also be determined based on A and / or other information.

[0374] In the embodiments of this application, the term "and / or" is simply a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0375] In the embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean 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 the present application.

[0376] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0377] The units described as separate components may or may not be physically separate, and 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 these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0378] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0379] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A method for non-terrestrial network satellite switching, characterized in that: Applicable to satellite handover from a first satellite network coverage area to a second satellite network coverage area, the method comprising: Sending first information, where the first information is used by the second satellite network to determine a first beam corresponding to the terminal device, where the first beam includes one or more beams; receiving a first switching command, where the first switching command is used to instruct the terminal device to perform the satellite switching; The first beam is related to the first resource and / or the second resource preconfigured by the second satellite network for the satellite switching.

2. The method according to claim 1, characterized in that The first switching command includes one or more of the following information: a grant pre-allocated by the second satellite network; a first resource preconfigured by the second satellite network; a beam index associated with a synchronization signal block in the second satellite network; a maximum signal quality reported within the coverage area received by the second satellite network and an associated beam index thereof; a beam index associated with a specified signal quality reported within a coverage area received by the second satellite network; an average value of the admission powers of terminal devices other than the terminal device in the second satellite network; The maximum value of the admission power of terminal devices other than the terminal device in the second satellite network.

3. The method according to claim 1 or 2, characterized in that: The first information includes multiple first measurement results of the terminal device measuring the reference signals of multiple beams of the second satellite network, and the multiple first measurement results are used to determine the first beam.

4. The method according to claim 3, characterized in that: The first measurement result corresponding to the first beam is a maximum value among the multiple first measurement results, or the largest M values ​​among the multiple first measurement results.

5. The method according to claim 3, characterized in that: A first measurement result corresponding to the first beam is greater than a first threshold.

6. The method according to any one of claims 1 to 5, characterized in that The first resource is a reserved resource for the satellite switching, and the second resource is a scheduled uplink resource, and the uplink resource is used by the terminal device to perform the satellite switching.

7. The method according to any one of claims 1 to 6, characterized in that After sending the first information, the method further includes: receiving second information, where the second information is used to indicate the first beam; After receiving the first switching command, a downlink channel sent by the second satellite network is detected according to the first beam.

8. The method according to claim 7, characterized in that The first beam is indicated by an identifier of a reference signal associated with the first beam.

9. The method according to any one of claims 1 to 8, characterized in that The satellite switching is a switching without a random access channel (RACH), and the second satellite network is a satellite network that satisfies a switching without a RACH condition. Before sending the first information, the method further includes: sending a first measurement report, where the first measurement report is used by the first satellite network to determine the second satellite network from a plurality of 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.

10. The method according to claim 7, characterized in that The second measurement result corresponding to the second satellite network is a maximum value among the multiple second measurement results, or is a second measurement result among the multiple second measurement results that is greater than or equal to a second threshold.

11. The method according to claim 3 or 9, characterized in that: The reference signal includes a synchronization signal block reference signal SSB-RS and / or a channel state information reference signal CSI-RS.

12. The method according to any one of claims 1 to 11, characterized in that The first beam is also used to carry one or more synchronization signal blocks for the terminal device to perform the satellite switching, and the indexes of the one or more synchronization signal blocks are associated with the first resource.

13. The method according to any one of claims 1 to 12, characterized in that The first handover command is a RACH-free handover command.

14. The method according to claim 13, characterized in that The satellite switching is performed when a first condition is met, the first switching command includes parameters of multiple candidate satellite networks, the first resource includes multiple uplink grants, and the method further includes: determining the second satellite network among the plurality of candidate satellite networks; An uplink authorization for the terminal device to perform switching is determined from among the multiple uplink authorizations.

15. The method according to claim 14, characterized in that The method further comprises: Sending third information to the first satellite network, where the third information is used to indicate the first condition; The third information includes one or more of the following information: A handover condition based on the SSB-RS being associated with at least one candidate satellite network; A switching condition based on the CSI-RS association with at least one candidate satellite network; at least one SSB-RS or CSI-RS measurement result / measurement information; At least one SSB-RS or CSI-RS associated with the contention-free random access resource.

16. A method for non-terrestrial network satellite switching, characterized in that: Applied to satellite handover from a first satellite network coverage area to a second satellite network coverage area, the method further comprising: receiving first information sent by a terminal device, where the first information is used by the second satellite network to determine a first beam corresponding to the terminal device, where the first beam includes one or more beams; sending the first information to the second satellite network; Sending a first switching command to the terminal device, where the first switching command is used to instruct the terminal device to perform the satellite switching; The first beam is related to the first resource and / or the second resource preconfigured by the second satellite network for the satellite switching.

17. The method according to claim 16, characterized in that The first switching command includes one or more of the following information: a grant pre-allocated by the second satellite network; a first resource preconfigured by the second satellite network; a beam index associated with a synchronization signal block in the second satellite network; a maximum value of the signal quality received by the second satellite network within the coverage area; an average value of the signal quality received by the second satellite network within the coverage area; an average value of the admission powers of terminal devices other than the terminal device in the second satellite network; The maximum value of the admission power of terminal devices other than the terminal device in the second satellite network.

18. The method according to claim 16 or 17, characterized in that The first resource is a reserved resource for the satellite switching, and the second resource is a scheduled uplink resource, and the uplink resource is used by the terminal device to perform the satellite switching.

19. The method according to any one of claims 16 to 18, characterized in that: After sending the first information to the second satellite network, the method further includes: receiving second information sent by the second satellite network; Send second information to the terminal device, where the second information is used to indicate the first beam.

20. The method according to any one of claims 16 to 19, characterized in that The satellite switching is a switching without a random access channel (RACH), and the second satellite network is a satellite network that satisfies a switching without a RACH condition. Before receiving the first information sent by the terminal device, the method further includes: receiving a first measurement report sent by a terminal device, where the first measurement report is used by the first satellite network to determine the second satellite network that meets a RACH-free switching condition 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.

21. The method according to claim 20, characterized in that The second measurement result corresponding to the second satellite network is a maximum value among the multiple second measurement results, or is a second measurement result among the multiple second measurement results that is greater than or equal to a second threshold.

22. The method according to claim 21, characterized in that The reference signal includes a synchronization signal block reference signal SSB-RS and / or a channel state information reference signal CSI-RS.

23. The method according to any one of claims 16 to 22, characterized in that The first handover command is a RACH-free handover command.

24. The method according to claim 23, characterized in that The satellite switching is performed when a first condition is met, the first switching command includes parameters of a plurality of candidate satellite networks, and the method further includes: receiving third information sent by the terminal device, where the third information is used to indicate the first condition; The third information includes one or more of the following information: A handover condition based on the SSB-RS being associated with at least one candidate satellite network; A switching condition based on the CSI-RS association with at least one candidate satellite network; at least one SSB-RS or CSI-RS measurement result / measurement information; At least one SSB-RS or CSI-RS associated with the contention-free random access resource.

25. A method for non-terrestrial network satellite switching, characterized in that: Applied to satellite handover from a first satellite network coverage area to a second satellite network coverage area, the method further comprising: receiving first information sent by the first satellite network, where the first information is used by the second satellite network to determine a first beam corresponding to a terminal device, where the first beam includes one or more beams; sending a handover request confirmation to the first satellite network according to the handover request sent by the first satellite network, wherein the handover request confirmation The first satellite network is used to send a first switching command to the terminal device, where the first switching command is used to instruct the terminal device to perform the satellite switching; The first beam is related to the first resource and / or the second resource preconfigured by the second satellite network for the satellite switching.

26. The method according to claim 25, characterized in that The first switching command includes one or more of the following information: a grant pre-allocated by the second satellite network; a first resource preconfigured by the second satellite network; a beam index associated with a synchronization signal block in the second satellite network; a maximum value of the signal quality received by the second satellite network within the coverage area; an average value of the signal quality received by the second satellite network within the coverage area; an average value of the admission powers of terminal devices other than the terminal device in the second satellite network; The maximum value of the admission power of terminal devices other than the terminal device in the second satellite network.

27. The method according to claim 25 or 26, characterized in that The first information includes multiple first measurement results of the terminal device measuring the reference signals of multiple beams of the second satellite network, and the multiple first measurement results are used to determine the first beam.

28. The method according to claim 27, characterized in that The first measurement result corresponding to the first beam is a maximum value among the multiple first measurement results, or the largest M values ​​among the multiple first measurement results.

29. The method according to claim 27, characterized in that A first measurement result corresponding to the first beam is greater than a first threshold.

30. The method according to any one of claims 25 to 29, characterized in that The first resource is a reserved resource for the satellite switching, and the second resource is a scheduled uplink resource, and the uplink resource is used by the terminal device to perform the satellite switching.

31. The method according to any one of claims 25 to 30, characterized in that After receiving the first information sent by the first satellite network, the method further includes: Sending second information to the first satellite network, where the second information is used to indicate the first beam; After sending the switching request confirmation to the first satellite network, a downlink channel is sent according to the first beam.

32. The method according to claim 31, characterized in that The first beam is indicated by an identifier of a reference signal associated with the first beam.

33. The method according to claim 27, characterized in that The reference signal includes a synchronization signal block reference signal SSB-RS and / or a channel state information reference signal CSI-RS.

34. The method according to any one of claims 25 to 33, characterized in that The first beam is also used to carry one or more synchronization signal blocks for the terminal device to perform the satellite switching, and the indexes of the one or more synchronization signal blocks are associated with the first resource.

35. The method according to any one of claims 25 to 34, characterized in that The first handover command is a handover command without a random access channel (RACH).

36. A terminal device, characterized in that: include: A sending unit, configured to send first information, where the first information is used by a second satellite network to determine a first beam corresponding to the terminal device, where the first beam includes one or more beams; A first receiving unit, configured to receive a first switching command, wherein the first switching command is used to instruct the terminal device to perform a satellite switching from a first satellite network coverage area to a second satellite network coverage area; The first beam is related to the first resource and / or the second resource preconfigured by the second satellite network for the satellite switching.

37. The terminal device according to claim 36, characterized in that: The first switching command includes one or more of the following information: a grant pre-allocated by the second satellite network; a first resource preconfigured by the second satellite network; a beam index associated with a synchronization signal block in the second satellite network; a maximum signal quality reported within the coverage area received by the second satellite network and an associated beam index thereof; a beam index associated with a specified signal quality reported within a coverage area received by the second satellite network; an average value of the admission powers of terminal devices other than the terminal device in the second satellite network; The maximum value of the admission power of terminal devices other than the terminal device in the second satellite network.

38. The terminal device according to claim 36 or 37, characterized in that: The first information includes multiple first measurement results of the terminal device measuring the reference signals of multiple beams of the second satellite network, and the multiple first measurement results are used to determine the first beam.

39. The terminal device according to claim 38, characterized in that: The first measurement result corresponding to the first beam is a maximum value among the multiple first measurement results, or the largest M values ​​among the multiple first measurement results.

40. The terminal device according to claim 38, characterized in that: A first measurement result corresponding to the first beam is greater than a first threshold.

41. The terminal device according to any one of claims 36 to 40, characterized in that: The first resource is a reserved resource for the satellite switching, and the second resource is a scheduled uplink resource, and the uplink resource is used by the terminal device to perform the satellite switching.

42. The terminal device according to any one of claims 36 to 41, characterized in that: The first receiving unit is further used to receive second information after sending the first information, where the second information is used to indicate the first beam; The terminal device further includes: The second receiving unit is configured to detect a downlink channel sent by the second satellite network according to the first beam after receiving the first switching command.

43. The terminal device according to claim 42, characterized in that: The first beam is indicated by an identifier of a reference signal associated with the first beam.

44. The terminal device according to any one of claims 36 to 43, characterized in that: The satellite handover is a handover without a random access channel (RACH), and the second satellite network is a satellite network that satisfies a handover without RACH condition. The sending unit is further configured to send a first measurement report before sending the first information, wherein the first measurement report is used for the first satellite network to determine the second satellite network from a plurality of 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.

45. The terminal device according to claim 44, characterized in that: The second measurement result corresponding to the second satellite network is a maximum value among the multiple second measurement results, or is a second measurement result among the multiple second measurement results that is greater than or equal to a second threshold.

46. ​​The terminal device according to claim 38 or 44, characterized in that: The reference signal includes a synchronization signal block reference signal SSB-RS and / or a channel state information reference signal CSI-RS.

47. The terminal device according to any one of claims 36 to 46, characterized in that: The first beam is also used to carry one or more synchronization signal blocks for the terminal device to perform the satellite switching, and the indexes of the one or more synchronization signal blocks are associated with the first resource.

48. The terminal device according to any one of claims 36-47, characterized in that: The first handover command is a RACH-free handover command.

49. The terminal device according to claim 48, characterized in that: The satellite switching is performed when a first condition is met, the first switching command includes parameters of multiple candidate satellite networks, the first resource includes multiple uplink grants, and the terminal device further includes: A first determining unit, configured to determine the second satellite network from among the plurality of candidate satellite networks; The second determining unit is used to determine the uplink authorization for the terminal device to perform switching from the multiple uplink authorizations.

50. The terminal device according to claim 49, characterized in that: The sending unit is further used to send third information to the first satellite network, where the third information is used to indicate the first condition; The third information includes one or more of the following information: A handover condition based on the SSB-RS being associated with at least one candidate satellite network; A switching condition based on the CSI-RS association with at least one candidate satellite network; at least one SSB-RS or CSI-RS measurement result / measurement information; At least one SSB-RS or CSI-RS associated with the contention-free random access resource.

51. A network device, characterized in that: The network device is a network device corresponding to the first satellite network, and the network device includes: A receiving unit, configured to receive first information sent by a terminal device; A first sending unit, configured to send the first information to a second satellite network, where the first information is used by the second satellite network to determine a first beam corresponding to the terminal device, where the first beam includes one or more beams; A second sending unit, configured to send a first switching command to the terminal device, wherein the first switching command is used to instruct the terminal device to perform a satellite switching from the first satellite network coverage area to the second satellite network coverage area; The first beam is related to the first resource and / or the second resource preconfigured by the second satellite network for the satellite switching.

52. The network device according to claim 51, characterized in that The first switching command includes one or more of the following information: a grant pre-allocated by the second satellite network; a first resource preconfigured by the second satellite network; a beam index associated with a synchronization signal block in the second satellite network; a maximum value of the signal quality received by the second satellite network within the coverage area; an average value of the signal quality received by the second satellite network within the coverage area; an average value of the admission powers of terminal devices other than the terminal device in the second satellite network; The maximum value of the admission power of terminal devices other than the terminal device in the second satellite network.

53. The network device according to claim 51 or 52, characterized in that: The first resource is a reserved resource for the satellite switching, and the second resource is a scheduled uplink resource, and the uplink resource is used by the terminal device to perform the satellite switching.

54. The network device according to any one of claims 51 to 53, characterized in that: The receiving unit is further used to receive second information sent by the second satellite network after sending the first information to the second satellite network; the first sending unit is further used to send second information to the terminal device, and the second information is used to indicate the first beam.

55. The network device according to any one of claims 51 to 54, characterized in that: The satellite handover is a handover without a random access channel (RACH), and the second satellite network is a satellite network that meets a handover without a RACH condition. The receiving unit is further configured to receive a first measurement report sent by the terminal device before receiving the first information sent by the terminal device, wherein the first measurement report is used by the first satellite network to determine the second satellite network from a plurality of 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.

56. The network device according to claim 55, characterized in that The second measurement result corresponding to the second satellite network is a maximum value among the multiple second measurement results, or is a second measurement result among the multiple second measurement results that is greater than or equal to a second threshold.

57. The network device according to claim 55, characterized in that The reference signal includes a synchronization signal block reference signal SSB-RS and / or a channel state information reference signal CSI-RS.

58. The network device according to any one of claims 51 to 57, characterized in that: The first handover command is a RACH-free handover command.

59. The network device according to claim 58, characterized in that The satellite switching is performed when a first condition is met, the first switching command includes parameters of multiple candidate satellite networks, and the receiving unit is further used to receive third information sent by the terminal device, and the third information is used to indicate the first condition; The third information includes one or more of the following information: A handover condition based on the SSB-RS being associated with at least one candidate satellite network; A switching condition based on the CSI-RS association with at least one candidate satellite network; at least one SSB-RS or CSI-RS measurement result / measurement information; At least one SSB-RS or CSI-RS associated with the contention-free random access resource.

60. A network device, characterized in that: The network device is a network device corresponding to the second satellite network, and the network device includes: A receiving unit, configured to receive first information sent by a first satellite network, where the first information is used to determine a first beam corresponding to the second satellite network and a terminal device, where the first beam includes one or more beams; A first sending unit, configured to send a handover request confirmation to the first satellite network according to the handover request sent by the first satellite network, wherein the handover request confirmation is used by the first satellite network to send a first handover command to the terminal device, wherein the first handover command is used to instruct the terminal device to perform a satellite handover from an area covered by the first satellite network to an area covered by the second satellite network; The first beam is related to the first resource and / or the second resource preconfigured by the second satellite network for the satellite switching.

61. The network device according to claim 60, characterized in that The first switching command includes one or more of the following information: a grant pre-allocated by the second satellite network; a first resource preconfigured by the second satellite network; a beam index associated with a synchronization signal block in the second satellite network; a maximum signal quality reported within the coverage area received by the second satellite network and an associated beam index thereof; a beam index associated with a specified signal quality reported within a coverage area received by the second satellite network; an average value of the admission powers of terminal devices other than the terminal device in the second satellite network; The maximum value of the admission power of terminal devices other than the terminal device in the second satellite network.

62. The network device according to claim 61, characterized in that The first information includes multiple first measurement results of the terminal device measuring the reference signals of multiple beams of the second satellite network, and the multiple first measurement results are used to determine the first beam.

63. The network device according to claim 62, characterized in that The first measurement result corresponding to the first beam is a maximum value among the multiple first measurement results, or the largest M values ​​among the multiple first measurement results.

64. The network device according to claim 62, characterized in that A first measurement result corresponding to the first beam is greater than a first threshold.

65. The network device according to any one of claims 60-64, characterized in that: The first resource is a reserved resource for the satellite switching, and the second resource is a scheduled uplink resource, and the uplink resource is used by the terminal device to perform the satellite switching.

66. The network device according to any one of claims 60-65, characterized in that: The first sending unit is further used to send second information to the first satellite network after receiving the first information sent by the first satellite network, where the second information is used to indicate the first beam; The network device also includes: The second sending unit is configured to send a downlink channel according to the first beam after sending the switching request confirmation to the first satellite network.

67. The network device according to claim 66, characterized in that The first beam is indicated by an identifier of a reference signal associated with the first beam.

68. The network device according to claim 62, characterized in that The reference signal includes a synchronization signal block reference signal SSB-RS and / or a channel state information reference signal CSI-RS.

69. The network device according to any one of claims 60 to 68, characterized in that: The first beam is also used to carry one or more synchronization signal blocks for the terminal device to perform the satellite switching, and the indexes of the one or more synchronization signal blocks are associated with the first resource.

70. The network device according to any one of claims 60-69, characterized in that: The first handover command is a handover command without a random access channel (RACH).

71. A communication device, characterized in that: It comprises a memory and a processor, wherein the memory is used to store a program, and the processor is used to call the program in the memory to execute the method as described in any one of claims 1-35.

72. A device, characterized in that The invention comprises a processor, which is used to call a program from a memory to execute the method as claimed in any one of claims 1 to 35.

73. A chip, characterized in that: It comprises a processor, which is used to call a program from a memory, so that a device equipped with the chip executes a method as claimed in any one of claims 1 to 35.

74. A computer-readable storage medium, characterized in that A program is stored thereon, the program causing a computer to execute the method according to any one of claims 1 to 35.

75. A computer program product, characterized in that The method comprises a program which causes a computer to execute the method according to any one of claims 1 to 35.

76. A computer program, characterized in that The computer program causes a computer to execute the method according to any one of claims 1 to 35.

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