Methods, terminal equipment, and network equipment for non-terrestrial network satellite handover.

Abstract

The present invention provides a method, terminal equipment and network equipment for non-terrestrial network satellite handover, which is advantageous in improving the access success rate of RACH-free handover in NTN cells. The method is applied to a satellite handover from a coverage area of ​​a first satellite network to a coverage area of ​​a second satellite network and includes the steps of: transmitting first information, the first information being used by the second satellite network to determine a first beam corresponding to terminal equipment, the first beam comprising one or more beams; and receiving a first handover command, the first handover command being used to instruct the terminal equipment to perform the satellite handover, the first beam relating to first and / or second resources pre-configured by the second satellite network for the satellite handover.

Description

[Technical Field]

[0001] This application relates to the field of communications technology, and more specifically, to a method, terminal equipment, and network equipment for handover of non-terrestrial network satellites. [Background technology]

[0002] To improve the user experience and reduce the time delay when terminal devices hand over from a source cell to a target cell, random access channel-less (RACH-less) handover will be introduced.

[0003] However, in some communication systems (for example, non-terrestrial network (NTN) systems), the propagation delay between terminal devices and network devices is relatively large. When performing RACH-less 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. [Overview of the project] [Problems that the invention aims to solve]

[0004] This application provides a method, terminal equipment, and network equipment for non-terrestrial network satellite handover. The following describes various embodiments of this application. [Means for solving the problem]

[0005] In a first embodiment, the method for a non-terrestrial network satellite handover is applied to a satellite handover from a coverage area of ​​a first satellite network to a coverage area of ​​a second satellite network and includes the steps of: transmitting first information, the first information being used by the second satellite network to determine a first beam corresponding to a terminal device, the first beam comprising one or more beams; and receiving a first handover command, the first handover command being used to instruct the terminal device to perform the satellite handover, the first beam relating to first and / or second resources pre-configured by the second satellite network for the satellite handover.

[0006] In a second aspect, a method for a non-terrestrial network satellite handover is provided, which is applied to a satellite handover from a coverage area of ​​a first satellite network to a coverage area of ​​a second satellite network, and includes the steps of: receiving first information transmitted from a terminal device, the first information being used by the second satellite network to determine a first beam corresponding to the terminal device, the first beam comprising one or more beams; transmitting the first information to the second satellite network; and transmitting a first handover command to the terminal device, the first handover command being used to instruct the terminal device to perform the satellite handover, wherein the first beam relates to first and / or second resources pre-configured by the second satellite network for the satellite handover.

[0007] In a third aspect, the method for a non-terrestrial network satellite handover is applied to a satellite handover from the coverage area of ​​a first satellite network to the coverage area of ​​a second satellite network, and includes the steps of: receiving first information transmitted from the first satellite network, the first information being used by the second satellite network to determine a first beam corresponding to a terminal device, the first beam comprising one or more beams; and transmitting a handover request confirmation to the first satellite network based on a handover request transmitted from the first satellite network, the handover request confirmation being used by the first satellite network to transmit a first handover command to the terminal device, the first handover command being used to instruct the terminal device to perform the satellite handover, wherein the first beam relates to first and / or second resources pre-configured by the second satellite network for the satellite handover.

[0008] In a fourth aspect, the present invention provides a transmitting unit for transmitting first information, the first information being used by a second satellite network to determine a first beam corresponding to the terminal equipment, the first beam comprising one or more beams; and a first receiving unit for receiving a first handover command, the first handover command being used by a first receiving unit to instruct the terminal equipment to perform a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network, the first beam relating to first and / or second resources pre-configured by the second satellite network for the satellite handover.

[0009] In a fifth aspect, a network device is provided, the network device being a network device corresponding to a first satellite network, the network device comprising: a receiving unit for receiving first information transmitted from a terminal device; a first transmitting unit for transmitting the first information to a second satellite network, the first information being used by the second satellite network to determine a first beam corresponding to the terminal device, the first beam comprising a first transmitting unit comprising one or more beams; and a second transmitting unit for transmitting a first handover command to the terminal device, the first handover command comprising a second transmitting unit used to instruct the terminal device to perform a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network, the first beam relating to first and / or second resources pre-configured by the second satellite network for the satellite handover.

[0010] In a sixth aspect, a network device is provided, the network device being a network device corresponding to a second satellite network, the network device comprising a receiving unit for receiving first information transmitted from a first satellite network, the first information being used by the second satellite network to determine a first beam corresponding to a terminal device, the first beam comprising a receiving unit comprising one or more beams, and a first transmitting unit for transmitting a handover request confirmation to the first satellite network based on a handover request transmitted from the first satellite network, the handover request confirmation being used by the first satellite network to transmit a first handover command to the terminal device, the first handover command being used by a first transmitting unit to instruct the terminal device to perform a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network, the first beam relating to first and / or second resources pre-configured by the second satellite network for the satellite handover.

[0011] In the seventh aspect, a communication device is provided that includes a memory for storing a program and a processor for calling the program in the memory and executing the method according to any one of the first to third aspects.

[0012] The eighth aspect provides an apparatus including a processor for calling a program from memory and performing the method described in any one of the first to third aspects.

[0013] In the ninth aspect, a chip is provided that includes a processor that causes a device equipped with the chip to perform the method described in any one of the first to third aspects by calling a program from memory.

[0014] In the tenth aspect, a computer-readable storage medium is provided which stores a program that causes a computer to perform the method described in any one of the first to third aspects.

[0015] In the eleventh aspect, a computer program product is provided which includes a program that causes a computer to perform the method described in any one of the first to third aspects.

[0016] The twelfth aspect provides a computer program that causes a computer to perform the method described in any one of the first to third aspects. [Effects of the Invention]

[0017] The terminal device in the embodiment of the present invention can transmit first information to the second satellite network before receiving a first handover command, thereby determining the first beam corresponding to the terminal device, which is shared between the second satellite network and the terminal device. The second satellite network preconfigures the first and / or second resources based on the determined first beam. As can be seen from the above, the terminal device can know the first beam that carries authorization for the first resource, thereby improving the success rate of access when performing a handover using the first resource.

Brief Description of the Drawings

[0018] [Figure 1] It is a wireless communication system applied to the embodiments of the present application. [Figure 2] It is an NTN system applied to the embodiments of the present application. [Figure 3] It is another NTN system applied to the embodiments of the present application. [Figure 4] It is a flowchart of a method for NTN satellite handover according to the embodiments of the present application. [Figure 5] It is a flowchart of a possible embodiment of the method shown in FIG. 4. [Figure 6] It is a flowchart of another possible embodiment of the method shown in FIG. 4. [Figure 7] It is a flowchart of another method for another NTN satellite handover according to the embodiments of the present application. [Figure 8] It is a schematic diagram of a possible embodiment for determining the handover path loss of a terminal device. [Figure 9] It is a schematic structural diagram of a terminal device according to the embodiments of the present application. [Figure 10] It is a schematic structural diagram of a network device according to the embodiments of the present application. [Figure 11] It is a schematic structural diagram of another network device according to the embodiments of the present application. [Figure 12] It is a schematic structural diagram of another terminal device according to the embodiments of the present application. [[ID=4*]] [Figure 13] It is a schematic structural diagram of yet another network device according to the embodiments of the present application. [Figure 14] It is a schematic structural diagram of yet another network device according to the embodiments of the present application. [Figure 15] It is a schematic structural diagram of a communication device according to the embodiments of the present application.

Modes for Carrying Out the Invention

[0019] The technical solutions of the embodiments of the present application will be described below with reference to the drawings of the embodiments of the present application, and as will be clear, the embodiments described are some embodiments of the present application, not all embodiments. All other embodiments that a person skilled in the art can obtain without creative work based on the embodiments of the present application are within the scope of protection of the present application.

[0020] The embodiments of this application can be applied to various communication systems. For example, the embodiments of this application can be applied to global systems of mobile communication (GSM), code division multiple access (CDMA) systems, wideband code division multiple access (WCDMA®) systems, general packet radio service (GPRS), long term evolution (LTE) systems, advanced long term evolution (LTE-A) systems, new radio (NR) systems, evolved NR systems, LTE-based access to unlicensed spectrum (LTE-U) systems, NR-based access to unlicensed spectrum (NR-U) systems, NTN systems, universal mobile telecommunication systems (UMTS), wireless local area networks (WLAN), and wireless fidelity systems. This invention is applicable to fidelity (WiFi) and 5th-generation (5G) communication systems. Embodiments of this invention are applicable to other communication systems, such as future communication systems, which may be, for example, 6th-generation (6G) mobile communication systems or satellite communication systems.

[0021] Conventional communication systems have limitations on the number of connections they can support, and are easy to implement. However, with advancements in communication technology, communication systems can support not only conventional cellular communication but also one or more other types of communication. For example, a communication system can support one or more of the following: 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 / vehicle-to-infrastructure (V2X) communication. The embodiments of this application can also be applied to communication systems that support the above communication methods.

[0022] The communication system in the embodiment of the present invention can be applied to carrier aggregation (CA) scenarios, dual connectivity (DC) scenarios, and standalone (SA) networking scenarios.

[0023] The communication system in the embodiment of the present application is applicable to the non-licensed spectrum. This non-licensed spectrum can also be considered as a shared spectrum. Alternatively, the communication system in the embodiment of the present application is also applicable to the licensed spectrum. This licensed spectrum can also be considered as a dedicated spectrum.

[0024] The embodiments of this application are applicable to NTN systems. For example, the NTN system may include an NTN system based on 4G, an NTN system based on NR, an NTN system based on the Internet of Things (IoT), and an NTN system based on the narrow-band Internet of Things (NB-IoT).

[0025] The communication system may include one or more terminal devices. The terminal devices according to the embodiments of this application may also be called user equipment (UE), access terminal, user unit, user station, mobile station (MS), mobile terminal (MT), remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, or user equipment.

[0026] 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., an NR system), or a terminal device in a future advanced public land mobile network (PLMN).

[0027] In some embodiments, a terminal device may refer to a device that provides voice and / or data connectivity to a user. For example, a terminal device may be a handheld device with wireless connectivity, an in-vehicle device, etc. Some specific examples of terminal devices may be a mobile phone, tablet PC (Pad), laptop computer, personal digital assistant (PDA), mobile internet device (MID), wearable device, virtual reality (VR) device, augmented reality (AR) device, wireless terminal in industrial control, wireless terminal in self-driving, wireless terminal in remote medical surgery, wireless terminal in smart grid, wireless terminal in transportation safety, wireless terminal in smart city, wireless terminal in smart home, etc.

[0028] In some embodiments, the terminal equipment may be located on land. For example, the terminal equipment may be located indoors or outdoors. In some embodiments, the terminal equipment may be located on water, for example, on a ship. In some embodiments, the terminal equipment may be located in the air, for example, on an airplane, balloon or satellite.

[0029] In addition to terminal equipment, the communication system may further include one or more network devices. The network devices in the embodiments of the present application may be devices for communicating with terminal equipment, and such network devices may also be called access network devices or wireless access network devices. Such network devices may be, for example, base stations. The network devices in the embodiments of the present application may refer to radio access network (RAN) nodes (or devices) that connect terminal equipment to a wireless network. The term "base station" broadly covers, or may be replaced by, various names such as NodeB, evolved NodeB (eNB), next-generation NodeB (gNB), relay station, access point, transmitting and receiving point (TRP), transmitting point (TP), primary evolutionary base station (MeNB), secondary evolutionary base station (SeNB), multi-standard radio (MSR) node, home base station, network controller, access node, radio node, access point (AP), transmitting node, transmitting and receiving node, base band unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (DU), and positioning node. A base station may also be a macro base station, micro base station, relay node, donor node, or similar, or a combination thereof. A base station may further refer to a communication module, modem, or chip installed within the aforementioned equipment or device. A base station may also refer to a mobile switching center, equipment that performs base station functions in D2D, V2X, and M2M communications, network-side equipment in a 6G network, or equipment that performs base station functions in a future communication system.Base stations can support networks with the same or different access technologies. The embodiments of this application do not limit the specific technologies employed in network equipment or the specific forms of equipment.

[0030] Base stations may be fixed or mobile. For example, a helicopter or drone may be configured as a mobile base station, with one or more cells moving according to the location of the mobile base station. In another example, a helicopter or drone may be configured as equipment for communicating with another base station.

[0031] In some examples, the network equipment in the embodiments of the present application refers to a CU or DU, or the network equipment may include both a CU and a DU. The gNB may further include an AAU.

[0032] As a non-limiting example, in the embodiments of the present application, the network equipment may have mobile characteristics; for example, the network equipment may be a mobile device. In some embodiments of the present application, the network equipment may be a satellite or a balloon station. In some embodiments of the present application, the network equipment may further be a base station installed at a location such as on land or in a body of water.

[0033] In embodiments of the present invention, network equipment can provide services to a cell, and terminal equipment communicates with the network equipment using the transmission resources (e.g., frequency domain resources, i.e., spectral resources) used by the cell, the cell may be a cell corresponding to network equipment (e.g., a base station), the cell may belong to a macro base station, or to a base station corresponding to a small cell, the small cell here including metro cells, micro cells, pico cells, femto cells, etc., these small cells are characterized by a small coverage range and low transmission power and are applied to provide high-rate data transmission services.

[0034] For illustrative purposes, Figure 1 is a schematic diagram of the architecture of a communication system according to an embodiment of the present application. As shown in Figure 1, the communication system 100 may include network equipment 110, and the network equipment 110 may be equipment that communicates with terminal equipment 120 (also referred to as a communication terminal or terminal). The network equipment 110 can provide communication coverage to a specific geographic area and can communicate with terminal equipment located within that coverage area.

[0035] Figure 1 illustrates one network device and two terminal devices. In some embodiments of the present application, the communication system 100 may include multiple network devices, and the coverage of each network device may include, but is not limited to, other terminal devices.

[0036] For illustrative purposes, Figure 2 is a schematic diagram of the NTN system architecture described above. The NTN system 200 shown in Figure 2 uses a satellite 210 as an aerial platform. As shown in Figure 2, the satellite radio access network includes the satellite 210, a service link 220, a feeder link 230, terminal equipment 240, a gateway (GW) 250, and a network 260 including base stations and a core network.

[0037] Satellite 210 is a spacecraft based on a space platform. Service link 220 refers to the link between satellite 210 and terminal equipment 240. Feeder link 230 refers to the link between gateway 250 and satellite 210. The Earth-based gateway 250 connects satellite 210 to a base station or core network, specifically determined according to the architecture selection.

[0038] The NTN architecture shown in Figure 2 is a bent-pipe transponder architecture. In this architecture, the base station is located on Earth behind the gateway 250, and the satellite 210 functions as a relay. The satellite 210 acts as a repeater, forwarding signals from the feeder link 230 to the service link 220, or forwarding signals from the service link 220 to the feeder link 230. In other words, the satellite 210 does not have base station functionality, and communication between terminal equipment 240 and the base station in the network 260 must be relayed by the satellite 210.

[0039] Exemplary, Figure 3 is a schematic diagram of another NTN system architecture. As shown in Figure 3, the satellite radio access network 300 includes a satellite 310, a service link 320, a feeder link 330, terminal equipment 340, a gateway 350, and a network 360. The difference from Figure 2 is that the satellite 310 has a base station 312, and the network 360 behind the gateway 350 includes only the core network.

[0040] The NTN architecture shown in Figure 3 is a regenerative transponder architecture. In this architecture, satellite 310 has a base station 312 and can be directly connected to the Earth-based core network via a link. Satellite 310 has the function of a base station, and terminal equipment 340 can communicate directly with satellite 310. Therefore, satellite 310 may also be called network equipment.

[0041] The communication system architecture shown in Figures 2 and 3 may include multiple network devices, and the coverage area of ​​each network device may include other terminal devices; however, the embodiments of this application are not limited to this.

[0042] In the embodiments of the present application, the communication system shown in Figures 1 to 3 may further include other network entities such as a mobility management entity (MME) and an access and mobility management function (AMF), but is not limited to these embodiments.

[0043] One point that can be understood is that, in the embodiments of this application, devices having communication functions in a network / system may be called communication devices. Taking the communication system 100 shown in Figure 1 as an example, the communication devices may include network devices 110 and terminal devices 120 having communication functions, and the network devices 110 and terminal devices 120 may be the specific devices described above. Here, a detailed explanation is omitted, and the communication devices may further include other devices in the communication system 100, such as a network controller, a mobility management entity, and other network entities, and are not limited to these in the embodiments of this application.

[0044] For the sake of understanding, some relevant technical knowledge relating to the embodiments of this application will be explained first. The following related technologies can be optionally combined with the technical solutions of the embodiments of this application as selectable means, and all of them fall within the scope of protection of the embodiments of this application. The embodiments of this application include at least some of the following:

[0045] NTN Systems With advancements in communication technology, communication systems (e.g., 5G) are opening up market potential for integrating satellite and terrestrial network infrastructure. For example, the 5G standard has made NTN, including its satellite segment, part of the 5G connectivity infrastructure of the well-known 3rd generation partnership project (3GPP®).

[0046] NTN refers to a network or network segment that uses radio frequency (RF) resources on a satellite or unmanned aerial system (UAS) platform. Taking satellites as an example, communication satellites are classified by their orbital altitude into low Earth orbit (LEO), medium Earth orbit (MEO), geostationary Earth orbit (GEO), and high elliptical orbit (HEO) satellites. Among these, LEO is an orbit centered on the Earth, with an altitude of 2,000 km or less, or at least 11.25 orbits 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 are in predictable or achievable orbits.

[0047] Satellites with different orbital altitudes have different orbital periods.

[0048] LEO: Typical altitudes are 250km to 1,500km, and orbital periods are 90 to 120 minutes.

[0049] MEO: Typical altitudes are 5,000 km to 25,000 km, and orbital periods are 3 to 15 hours.

[0050] GEO: Altitude is approximately 35,786 km, and orbital period is 24 hours.

[0051] As can be seen from Figures 2 and 3, which use the aforementioned satellite as an example, typical scenarios for NTN systems accessed by terminal equipment relate to NTN transparent payloads or NTN regenerative payloads. The vented-pipe transponder architecture shown in Figure 2 corresponds to NTN transparent payloads, and the regenerative transponder architecture shown in Figure 3 corresponds to NTN regenerative payloads.

[0052] In NTN systems, propagation delay between terminal equipment and network equipment primarily depends on the height of the satellite or aircraft-mounted platform and the load type in NTN. Compared to terrestrial networks (TN), propagation delay between terminal equipment and network equipment in NTN systems is significantly longer. For example, in cellular networks used by conventional NR, propagation delay in ground mobile systems is typically less than 1 millisecond, while propagation delay in NTN systems ranges from several milliseconds to several hundred milliseconds.

[0053] The NTN system has relatively high mobility, and the area covered by aerial platforms such as satellites is relatively large. Therefore, terminal equipment needs to perform timely cell handovers to maintain communication stability. For simplicity, the following explanation will use satellites as an example.

[0054] In the NTN system, as satellites move, terminal equipment needs to perform a satellite handover from the source NTN satellite (NTN1) to the target NTN satellite (NTN2). During the handover process, terminal equipment typically activates two timers to enhance timing relationships. These two timers are Timer T304 and Timer T430.

[0055] The terminal device activates timer T304 when initiating the handover process. During the handover process, when timer T304 expires, the terminal device initiates the radio resource control (RRC) connection re-establishment process with the target NTN cell.

[0056] The terminal equipment activates timer T430 during the synchronization of the downlink (DL) and uplink (UL). As can be seen from the above, relative movement occurs between the source satellite NTN1 and the terminal equipment on Earth, and therefore the auxiliary information (NTN-config) of source satellite NTN1 is relevant to validity issues. Timer T430 is used to ensure that the terminal equipment continuously acquires valid auxiliary information from source satellite NTN1. For example, timer T430 can be used to control the terminal equipment to acquire valid clock auxiliary information in the system information block (SIB) 19, thereby ensuring that the auxiliary information from source NTN1 acquired by the terminal equipment remains valid before the handover is completed.

[0057] Auxiliary information for source satellite NTN1 includes, for example, satellite ephemeris and common timing advance (TA) parameters. In the case of NTN1, the network side can broadcast ephemeris information and common TA parameters. For example, SIB19 contains satellite auxiliary information for NTN access. Before accessing NTN2, terminal equipment has valid global navigation satellite system (GNSS) position, satellite ephemeris information, and common TA.

[0058] Handover without RACH (HO) When source cells, target cells, and terminal devices are synchronized, a RACH-free handover solution can be implemented to reduce handover time delays and improve the user experience. In a synchronized network, the subframe boundaries between source and target cells are considered aligned, and therefore, terminal devices can be handed over from the source cell to the target cell at a point agreed upon by all three parties, without requiring a random access process. For example, when source cells, target cells, and terminal devices are synchronized, terminal devices can be handed over from the source cell to the target cell at a system frame number (SFN) agreed upon by all three parties, without requiring random access.

[0059] One of the main objectives of the Random Access Channel (RACH) handover process is to obtain the Target Audience (TA) of the target cell. Under RACH handover conditions, the RACH process allows the terminal device to obtain the TA of the target cell. Without the RACH process, if the source and target cells are time-synchronized, the terminal device can obtain the TA of the target cell without an explicit TA instruction.

[0060] Another objective of the RACH process during the handover period is to obtain uplink transmission permission. If there is no RACH process in the target cell, uplink permission needs to be allocated in the target cell. In some embodiments, for initial UL transmission in a no-RACH handover, pre-allocated permission in the no-RACH handover command is supported. That is, the target cell can pre-allocate through uplink permission (UL-grant) in the handover command. From the start of synchronization between the terminal device and the target cell, the pre-allocated uplink permission can remain valid for a certain period of time. For example, when performing a no-RACH handover in an NR terrestrial network, the propagation delay between the terminal device and the network device is relatively low. Based on the propagation delay information 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 in order to send the RRCReconfigurationComplete message (i.e., handover complete message) when the terminal device accesses the target cell.

[0061] For initial UL transmission in RACH-less handovers, support for pre-allocation authorization in RACH-less handover instructions is required. NTN systems can support RACH-less handovers in NTN, whether the handover is between satellites with the same feeder link or between satellites with different feeder links. Satellites with the same feeder link mean satellites that share the same gateway or the same network equipment (e.g., gNB).

[0062] Compared to the cellular networks used by some communication systems (e.g., NR), NTN has relatively large propagation delays between terminal equipment and satellites, and relatively large propagation delays in the air interface for terminal equipment to accurately receive handover commands. When implementing RACH-less handover in NTN systems, the large propagation delays may cause terminal equipment to miss configured uplink resources in the process of accessing the target cell, resulting in handover access failure. For example, in RACH-less handover in NTN, regarding the delay of the handover command from the target satellite to the terminal equipment, the source satellite may experience further radio link control (RLC) layer retransmissions or hybrid automatic repeat reQuest (HARQ) retransmissions when forwarding the handover command, increasing the propagation delay of the terminal equipment's air interface and thus failing to access the device.

[0063] In some scenarios, NTN achieves beam-based coverage, similar to other communication systems (e.g., 5G(NR)). For example, each serving cell has a beam carrying one or more synchronization signal blocks (SSBs) or synchronization signal and PBCH blocks (SS / PBCH blocks). For simplicity, hereafter, SSB may refer to either a synchronization signal block or a synchronization signal / PBCH block.

[0064] SSB beams are typically either static or semi-static. Each cell can have a maximum of 4 to 64 SSB beams, forming a (beam)mesh that covers the entire cell. Typically, terminal equipment searches for and measures beams after power-up, maintaining a set of candidate beams. This set of candidate beams may include beams from multiple cells. Terminal equipment can measure beam signals to determine beam quality. For example, terminal equipment can measure the reference signal received power (RSRP) of the beam synchronization signal (SS), i.e., SS-RSRP. Alternatively, terminal equipment can measure the reference signal received quality (RSRQ) based on the synchronization signal, i.e., SS-RSRQ. Furthermore, terminal equipment can measure the signal-to-noise and interference ratio (SINR) of the beam based on the synchronization signal, i.e., SS-SINR.

[0065] In some embodiments, network equipment (e.g., gNB) can determine the appropriate beam based on Layer 3 (L3) measurement reports or terminal equipment location reports. L3 measurement reports include beam level results. However, in some cases, network equipment does not have this information, such as location reports.

[0066] As can be seen from the above, in a RACH-less handover, authorization is pre-allocated. If the appropriate beam for the terminal device cannot be determined, the target cell will waste resources if it assigns authorization on all beams, and if it assigns authorization on some beams, the terminal device may miss out on configured uplink resources.

[0067] For example, in NTN, if there is no location report or L3 measurement report for target NTN2, it is not possible to know the beam associated with the terminal equipment, or the appropriate beam may change before or during the RACH-less handover process, thereby making it impossible to pre-configure the appropriate uplink resources.

[0068] Furthermore, for example, when combining conditional handover (CHO) with handover without RACH, the timing of the handover is uncertain, and similarly, it may not be possible to pre-configure the appropriate uplink resources.

[0069] In summary, when introducing RACH-less handover in the NTN scenario, the problem that needs to be solved is how to improve the success rate of handover access for terminal devices by reserving and pre-configuring uplink resources in the RACH-less handover instruction.

[0070] It should be noted that the problem of large propagation delays and inappropriate configuration of reserved resources causing handover failures when introducing RACH-less handover in the NTN system described above is only one example. The embodiment of this application may be applied to any type of handover scenario where propagation delays are relatively large and terminal devices cannot communicate with the target cell through random access.

[0071] Based on this, embodiments of the present invention provide a method for NTN satellite handover. The method allows terminal equipment to transmit selected beam or beam measurement information to the target satellite network before performing a cell handover, thereby enabling the target satellite network to configure uplink resources with the appropriate beam based on this information and improve the handover success rate.

[0072] For ease of understanding, the method proposed by the embodiment of the present application will be described in detail below with reference to Figure 4. Figure 4 is created from the perspective of the interaction between terminal equipment, the first satellite network, and the second satellite network. The method shown in Figure 4 is applied to satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network.

[0073] The terminal equipment is one of the terminal devices described above. In some embodiments, the terminal equipment is a communication device that is serviced by satellite in the NTN system. In some embodiments, the terminal equipment is a communication device with a relatively low service transmission rate.

[0074] The first satellite network and the second satellite network are NTN networks that integrate ground facilities and aerial platforms such as satellites. As mentioned above, the aerial platforms such as satellites in the first satellite network and the second satellite network can provide services as network equipment or as relays. Taking satellites as an example, the network equipment corresponding to the first satellite network and the second satellite network may be satellites or ground base stations. For simplicity, satellites corresponding to the first satellite network may be called first satellites, and satellites corresponding to the second satellite network may be called second satellites. Network equipment corresponding to the first satellite network may be called first network equipment, and network equipment corresponding to the second satellite network may be called second network equipment.

[0075] The first satellite network is an NTN network that provides services to terminal equipment at the present time. The first satellite network may also be called Source NTN or Source Satellite Network. In some embodiments, the first satellite network provides services to terminal equipment within its coverage area through its corresponding network equipment.

[0076] The network equipment corresponding to the first satellite network is communication equipment that provides services to terminal equipment at the present time. In some embodiments, the network equipment may be equipment that moves relative to the terminal equipment. For example, the first network equipment may be a base station on a satellite that provides services to terminal equipment. Alternatively, for example, the first network equipment may be a base station mounted on a low-altitude aircraft. In some embodiments, the network equipment may be equipment that is stationary relative to the terminal equipment or the Earth. For example, if the satellite in the first satellite network is a relay, the first network equipment may be a base station on the ground that communicates with the satellite via a gateway.

[0077] The coverage area of ​​the first satellite network is the area in which the first satellite network provides communication services. In some scenarios, the coverage area of ​​the first satellite network may be called a source cell. In some embodiments, the coverage area of ​​the first satellite network may include one or more ground network cells.

[0078] The second satellite network is an NTN network that provides services to terminal equipment after the first satellite network. The second satellite network may also be called the target NTN or target satellite network. In some embodiments, the second satellite network provides services to terminal equipment within the coverage area by its corresponding network equipment. In some embodiments, the first satellite network can determine a number of satellite networks that can provide services to terminal equipment based on satellite trajectory and / or ephemeris information, and determine one second satellite network. In some embodiments, terminal equipment can determine the second satellite network from among several candidates by signal measurement.

[0079] The network equipment corresponding to the second satellite network is the following communication equipment that provides services to the terminal equipment. In some embodiments, the second network equipment may be equipment that moves relative to the terminal equipment, equipment that is stationary relative to the terminal equipment, or equipment that is stationary relative to the Earth, which will not be repeated here.

[0080] The coverage area of ​​the second satellite network is the area in which the second satellite network provides communication services. In some scenarios, the coverage area of ​​the second satellite network may be called a target cell. In some embodiments, the coverage area of ​​the second satellite network may include one or more ground network cells.

[0081] A satellite handover may be a handover to the satellite corresponding to the area where the terminal device is located. For example, a satellite handover may be a cell handover. Exemplary, the physical cell identity (PCI) of the coverage area in a satellite handover does not change.

[0082] Referring to Figure 4, in step S410, the terminal device transmits the first information to the first satellite network.

[0083] The first information is used by the second satellite network to determine the first beam corresponding to the terminal equipment, thereby pre-configuring the first resource for satellite handover to the terminal equipment. The first beam is also used by the second satellite network to schedule the second resource related to satellite handover. In other words, the first beam is related to the first and / or second resource for satellite handover of the second satellite network.

[0084] In some embodiments, the first resource may be a configured or pre-configured resource. For example, the first resource may be a reserved resource for terminal equipment to perform a satellite handover. Alternatively, the first resource may include uplink permission for a satellite handover.

[0085] In some embodiments, the second resource may be a scheduled uplink resource, which may be dynamically scheduled.

[0086] For example, the first resource is a reserved resource for satellite handover, and the second resource is a scheduled uplink resource, which is used by terminal equipment to perform satellite handover. For instance, the first resource is a reserved resource for terminal equipment to transmit the initial uplink transmission, and the second resource is a resource dynamically scheduled by the physical downlink control channel (PDCCH).

[0087] The first beam is the beam in all the beams that the second satellite network uses to cover its service area. In some embodiments, the first beam may be a single beam. In some embodiments, the first beam may be multiple beams. Typically, the number of beams in the first beam is less than the total number of beams in the second satellite network, so that the second satellite network can allocate uplink resources using only a portion of the beams, which can effectively conserve resources.

[0088] Terminal equipment can determine multiple beams of the second satellite network by various means. In some embodiments, before the handover process, the first satellite network notifies the terminal equipment of the target satellite network for the handover (i.e., the second satellite network), and then the terminal equipment can determine multiple beams of the second satellite network by measurement. In some embodiments, before the handover process, the first satellite network can provide the terminal equipment with information indicating multiple beams in the second satellite network. This information may identify the multiple beams, or it may identify the beam information by identifying the reference signals transmitted by the beams. For example, the terminal equipment may identify the beam information by SSB. Alternatively, for example, after receiving this information, the terminal equipment may determine the beams by identifying and measuring one or more characteristics of the reference signals. These one or more characteristics may be, for example, power, RSRP, RSRQ, etc.

[0089] The first beam may be one or more beams that allow terminal equipment to access the second satellite network, or it may be a suitable beam for terminal equipment to conduct subsequent communications with the second satellite network. In other words, terminal equipment can establish communication with the second satellite network by the first beam. When the second satellite network configures or preconfigures the first resources for satellite handover on the first beam, terminal equipment can better utilize these resources to access the network, thereby avoiding resource waste and improving the success rate of satellite handover.

[0090] The first beam is associated with the first resources pre-configured by the second satellite network for satellite handover. Exemplarily, the second satellite network assigns permission for satellite handover on the first beam. The second satellite network can make resource reservations associated with the first beam, and the handover request confirmation sent to the first satellite network includes information related to the resource reservation.

[0091] The first resource may be a time-frequency resource reserved by the second satellite network for satellite handover by terminal equipment. For example, the first resource may be used for initial uplink transmission in a no-RACH handover by terminal equipment. Since terminal equipment uses these resources only when performing a handover, the first resource is usually pre-configured by the second satellite network. In some scenarios, it should be understood that the second satellite network can also dynamically configure the first resource.

[0092] In some embodiments, the first resource may include one or more pre-assigned permissions. For example, terminal devices may be accessed by these pre-assigned permissions.

[0093] The second resource may be a resource scheduled by the second satellite network in response to communication demand, thereby enabling terminal equipment to perform uplink transmission. 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.

[0094] For example, the second satellite network may transmit a PDCCH on the first beam. For instance, in a no-RACH handover, the second satellite network does not transmit the media access control control element (MACCE) of the terminal device's conflict resolution identifier, but instead transmits a PDCCH or physical downlink shared channel (PDSCH) that can be addressed to the cell-radio network temporary identifier (C-RNTI).

[0095] For example, a MAC entity does not need to select uplink authorization for the logical channel corresponding to the data radio bearer (DRB) before completing a no-RACH handover. This uplink authorization is used in the HARQ process for the initial UL transmission. A no-RACH handover is considered complete when a PDCCH addressed to C-RNTI and scheduled for DL / UL is received after the initial UL transmission.

[0096] In some embodiments, the first resource may include one or more pre-assigned uplink (UL) licenses. These licenses may be used by terminal equipment to access the network. For example, based on measurement reports, the second satellite network may provide one or more UL licenses to terminal equipment. Each of the one or more UL licenses may be associated with the first beam in the second satellite network.

[0097] For example, a terminal device can send an initial uplink transmission using available UL authorizations (RRC, MAC, PHY). The initial uplink transmission includes messages such as RRCReconfigurationComplete.

[0098] In some embodiments, the first resource may be associated with the SSB index of the first beam, so that the terminal equipment can determine the beam on which the first resource is located by the SSB index. For example, the first beam is further used to carry one or more synchronization signal blocks for which the terminal equipment performs a satellite handover. The index of the one or more synchronization signal blocks is associated with the first resource.

[0099] Exemplary, the first information may include indices of one or more SSBs measured by the terminal equipment. The second satellite network can determine the first beam by the SSB index. When one SSB is mapped to one beam, the beam's coverage range is much larger than that of a TN, and different frequency reuse modes are considered between the beams, so an SSB with a detectable position for the UE at a particular time indicates the appropriate beam for subsequent communications. However, in an NTN, one or more SSBs may be associated with one beam. When multiple SSBs are mapped to one beam, the channel quality is similar or exactly the same because similar satellite configurations and propagation are shared. In this case, the terminal equipment may not be able to perform SSB selection in a RACH-less handover. To solve this problem, when the second satellite network assigns the first beam to the terminal equipment for a RACH-less handover, the first beam can be associated with an SSB index. The terminal equipment can then know the reservation information for the pre-allocated resources associated with this SSB index.

[0100] For example, a second satellite network may identify authorizations associated with one or more SSB indices. Authorizations associated with SSB indices are used to indicate SSBs and corresponding resources available for RACH-free handover. Once terminal equipment accesses these SSBs, it can directly synchronize and access the network.

[0101] The first information may include multiple types of content for the second satellite network to determine the first beam. In some embodiments, the first information can directly indicate the first beam selected by a terminal device. That is, the terminal device can self-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 may include multiple first measurement results from 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 may be a single measurement report. For example, the terminal device can measure the intensity of each reference signal, generate a measurement report for each, and provide the measurement reports to the second satellite network.

[0102] In some embodiments, when terminal equipment performs beam selection, the beam selection may be periodic or aperiodic, or it may be triggered. During satellite handover, the association between pre-assigned authorizations and beams or SSBs allows the second satellite network to know the beam selected by the terminal equipment and schedule subsequent transmissions using the corresponding beam.

[0103] The first measurement result may be the measurement result of the beam reference signal from the terminal equipment. In some embodiments, the reference signal may be a synchronization signal block reference signal (SSB-RS), or a channel state information (CSI) reference signal (RS), that is, it may be CSI-RS, or CSI-RS and SSB-RS.

[0104] The first measurement result may be used to indicate the signal quality of the beam's reference signal. Signal quality may also be called signal strength. To indicate signal quality, the first measurement result may be the RSRP, RSRQ, or SINR mentioned above, or a reference signal strength indication (RSSI), or a combination of the above.

[0105] In some embodiments, a terminal device or a second satellite network can determine a first beam by a plurality of first measurement results and / or a first threshold. The first threshold may be set by the terminal device or by the second satellite network. In some embodiments, the terminal device and the second satellite network can share the parameters by the first satellite network, so that the first beams determined by both are the same or similar.

[0106] For example, the first measurement result corresponding to the first beam may be the maximum value among several first measurement results. In this scenario, the first beam may consist of a single beam. For instance, the second satellite network may generate a UL authorization associated with the reference signal with the highest intensity.

[0107] For example, the first measurement result corresponding to the first beam may be a relatively large number of the first measurement results among a 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 a 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 authorization for a specified number of beams that have the best quality (e.g., based on intensity) of the measured reference signals.

[0108] For example, the first measurement result corresponding to the first beam may be multiple measurement results greater than the 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. Alternatively, for example, the second satellite network may generate UL authorization for a reference signal greater than at least the RSRP threshold. To ensure that the first beam determined by the terminal equipment matches the first beam of the second satellite network, the second satellite network may transmit second information to the terminal equipment via the first satellite network to indicate the first beam. Once the second information indicates one or more beams, the terminal equipment monitors the PDCCH of the second satellite network based on the indicated beam, thereby improving the success rate of access, or otherwise monitors the PDCCH based on the selected beam. For example, the terminal equipment directly proposes the first beam selected in the first information, and the second satellite network transmits the PDCCH based on the first beam.

[0109] In some embodiments, a terminal device can receive second information in a first handover command it receives.

[0110] In some embodiments, a terminal device may receive second information after transmitting first information. The second information is used to indicate the first beam. After receiving the first handover command, the terminal device may detect the downlink channel transmitted from the second satellite network based on the first beam indicated by the second information.

[0111] For example, the first beam may be indicated by an identifier of a reference signal associated with the first beam. For instance, a second satellite network can identify a reference signal associated with a UL authorization by associating the reference signal identifier (e.g., an index) with the UL authorization. Optionally, the second satellite network may include the identifier in a message (e.g., an RRC message) providing the UL authorization to terminal equipment.

[0112] Prior to the terminal device performing a satellite handover, the first information may be transmitted to the first satellite network on a different occasion. In some embodiments, the first information may be transmitted to the first satellite network after the first satellite network has made a handover decision. Exemplarily, after the first satellite network has determined the second satellite network by a handover decision, the terminal device may measure multiple beams of the second satellite network to generate the first information. Exemplarily, after the first satellite network has determined the second satellite network by a handover decision, information on multiple beams in the second satellite network may be transmitted to the terminal device. The terminal device performs beam measurements or beam selection after receiving this information to generate the first information to be transmitted. In some embodiments, the first information may be included in a first measurement report transmitted from the terminal device. For example, if the second satellite network does not require a determination of the first satellite network, or does not require beam information of the second satellite network to be notified to the terminal device by the first satellite network, the terminal device may include the first information in the first measurement report for the handover.

[0113] In step S420, the first satellite network transmits the first information to the second satellite network. Since the terminal equipment has not yet accessed the second satellite network, the first information needs to be forwarded to the second satellite network by the first satellite network. Furthermore, the first satellite network needs to forward the second information, which directs the first beam transmitted from the second satellite network, to the terminal equipment.

[0114] In some embodiments, the first information may be included in a handover request transmitted from the first satellite network to the second satellite network, thereby reducing interaction between the two satellite networks and conserving air interface resources.

[0115] In some embodiments, the second information may be included in the handover request confirmation transmitted from the second satellite network to the first satellite network, and similarly, interaction between the two satellite networks can be reduced and air interface resources can be saved.

[0116] Next, referring to Figure 4, in step S430, the first handover instruction is received.

[0117] The first handover command received by the terminal device originates from the first satellite network. That is, the first satellite network currently providing services to the terminal device instructs the terminal device to perform a handover. In some embodiments, the first network device corresponding to the first satellite network transmits the first handover command to the terminal device.

[0118] A first handover command is used to trigger a handover by a terminal device. In some embodiments, the first satellite network can trigger a handover by sending RRC signaling to a terminal device. For example, the first satellite network can trigger a no-RACH handover by sending an RRCReconfiguration message to a terminal device. In some embodiments, the first satellite network can trigger a handover by separately configured information. For example, messages related to a no-RACH handover command may be sent by additional proprietary signaling.

[0119] The first handover command is used to instruct a terminal device to perform a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network. In some embodiments, due to satellite movement, the area in which the terminal device is located changes from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network, requiring a handover. In some embodiments, due to terminal device movement or edge communication, the area in which the terminal device is located changes from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network, requiring a handover.

[0120] The first handover instruction may be a satellite handover instruction of several different forms. In some embodiments, the first handover instruction may be an instruction that prevents the terminal device from performing a satellite handover via RACH. For example, the first handover instruction is a RACH-free handover instruction. Also, for example, the first handover instruction does not provide the terminal device with resources for random access. Hereinafter, embodiments of the present application will be specifically described using a RACH-free handover as an example.

[0121] In some embodiments, the first satellite network can decide whether or not to send a no-RACH handover command to terminal equipment based on the actual situation. For example, if the service network of terminal equipment needs to hand over from the first satellite network to the second satellite network due to satellite movement or other reasons, the no-RACH handover can be preferred, thereby reducing handover time delays.

[0122] If the satellite handover is a no-RACH handover, the first satellite network must determine a second satellite network that satisfies the no-RACH handover conditions before sending the first handover command. As can be seen from the above, there are multiple satellite networks that can serve the terminal equipment, and these satellite networks may be called candidate satellite networks. If none of the multiple candidate satellite networks are a second satellite network that satisfies the no-RACH handover conditions, the terminal equipment can perform the satellite handover according to the conventional handover process. That is, if the first satellite network does not find a second satellite network that satisfies the conditions, the first handover command is a command for the normal handover method.

[0123] In some embodiments, the first satellite network can determine the second satellite network based on measurement reports from terminal equipment. For example, the first satellite network can determine a second satellite network that meets certain conditions based on the measurement results in the measurement report. In some embodiments, the first satellite network can determine the second satellite network itself. For example, after determining multiple satellite networks that can provide services to terminal equipment, the first satellite network can determine the second satellite network based on the location information or movement information of the terminal equipment.

[0124] In some embodiments, if the satellite handover is a no-RACH handover, the terminal equipment can transmit a first measurement report to the first satellite network. The first measurement report may include a plurality of second measurement results in which the terminal equipment measures reference signals of a plurality of candidate satellite networks, thereby determining from the plurality of candidate satellite networks a second satellite network that satisfies the no-RACH handover condition.

[0125] As mentioned above, the reference signals of multiple candidate satellite networks may be SSB-RS and / or CSI-RS. The signal quality of the reference signals may be at least one of RSRP, RSRQ, SINR, and RSSI.

[0126] For example, a terminal device can measure the signal power and / or signal quality of a reference signal in the coverage area of ​​each candidate satellite network. If there are multiple candidate satellite networks, multiple second measurement results can be obtained. These second measurement results may be used to prepare the first measurement report. That is, if there are multiple target NTNs, for example NTN2, NTN3, etc., the terminal device will report the measurement results of the reference signal based on multiple target NTNs.

[0127] For example, multiple second measurement results from a first measurement report can be used to determine whether a second satellite network satisfies the RACH-free handover condition. For instance, the second satellite network can be determined by whether any of the multiple CSI-RS measurement results satisfy the RACH-free handover condition. Alternatively, for example, one can determine whether any single SSB-RS measurement result from one or more candidate satellite networks satisfies the RACH-free handover condition.

[0128] In some embodiments, satellite handover may be a PCI-less satellite handover (not requiring L3 mobility). In PCI-less scenarios, terminal equipment can hand over to a target satellite that has the same cell configuration, except for specific satellite information. Exemplary, in PCI-less scenarios, terminal equipment may not need to change any specific configuration of the terminal equipment other than TA acquisition and DL / UL synchronization. That is, the terminal equipment does not need to be reconfigured. Therefore, PCI-less scenarios are one specific situation for handovers between satellites having the same gateway / gNB.

[0129] If a first satellite network receives RACH-free handover information from a candidate satellite network containing the same PCI, that candidate satellite network may be designated as the preferred target satellite network.

[0130] In certain handover schemes, such as RACH-less handover, the quality of the reference signal on the second satellite network is extremely important. For example, in RACH-less handover, the signal quality of the second satellite network's downlink must be above a certain threshold to ensure reliable initial UL transmission. Alternatively, a RACH-less handover can be triggered simply by the downlink RSRP measured by the terminal equipment being above the RSRP threshold.

[0131] For example, the second measurement result corresponding to the second satellite network is the maximum value among multiple second measurement results. For instance, the first satellite network can select the satellite network with the largest RSRP as the second satellite network from among several candidate satellite networks.

[0132] Exemplary, the second measurement result corresponding to the second satellite network is one of several second measurement results that is above the second threshold. The second threshold may be set by the first satellite network. In some embodiments, the second threshold may differ 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.

[0133] For example, if the first measurement report includes the RSRPs of SSB-RS for multiple candidate satellite networks, and the RSRP of a certain candidate satellite network is equal to or greater than the second threshold corresponding to the RSRP, then that candidate satellite network is the second satellite network. Based on the measurement report of the terminal equipment, the first satellite network performs a handover to the candidate satellite network using a no-RACH handover as the optimal handover method.

[0134] For example, a terminal device reports a first measurement report to the first satellite network. After receiving the first measurement report, the first satellite network decides whether or not to trigger a no-RACH handover for the terminal device. A no-RACH handover for the terminal device can be triggered simply if the downlink RSRP measured by the terminal device is above the RSRP threshold.

[0135] In some embodiments, the first satellite network sends a handover request to the second satellite network before sending a handover command, and sends the first handover command after receiving an acknowledgment from the second satellite network. Exemplary, after determining that there is a satellite network that meets the conditions and triggering a no-RACH handover, the first satellite network sends a no-RACH 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, the first satellite network may send the first handover command to the terminal equipment.

[0136] For example, a handover request acknowledgment may also be called a handover request response, response information, etc. A handover request acknowledgment may also be indicated as HANDOVER REQUEST ACKNOWLEDGE.

[0137] The handover request acknowledgment transmitted from the second satellite network may include various pieces of information that the first satellite network uses to notify terminal equipment via the first handover command. For example, the handover request acknowledgment may include UL authorization determined by the second satellite network. Alternatively, for example, the handover request acknowledgment may include the SSB index and pre-assigned authorizations related to the terminal equipment's transmission on the second satellite network.

[0138] In some embodiments, the handover request confirmation includes information related to resource reservations, or coefficient information related to power when terminal equipment hands over to and accesses the second satellite network. Refer to Figure 7 for an explanation of the power-related information.

[0139] For example, to reduce interaction between terminal equipment, the first satellite network, and the second satellite network, the handover request confirmation includes the aforementioned second information. That is, the second satellite network can indicate the first beam or SSB index associated with the first resource by the handover request confirmation.

[0140] The first satellite network can generate a first handover instruction based on confirmation of a handover request from the second satellite network. The first handover instruction may contain multiple pieces of information.

[0141] In some embodiments, the first handover instruction includes one or more pieces of information, including a permission 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 signal quality and associated beam index reported within the coverage area received by the second satellite network, a beam index associated with a specified signal quality reported within the coverage area received by the second satellite network, the average admission power of non-terminal equipment in the second satellite network, and the maximum admission power of non-terminal equipment in the second satellite network.

[0142] For example, the pre-allocated, pre-configured first resources provided by the second satellite network are used by the terminal equipment for handover.

[0143] For example, a beam index related to a synchronization signal block in the second satellite network refers to a beam index corresponding to a pre-allocated permission or SSB related to the first resource in the second satellite network.

[0144] For example, 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 received signal quality in the second satellite network, thereby facilitating terminal equipment to determine the access beam.

[0145] Selectively, a terminal device can select the maximum signal quality and beams associated with the maximum signal quality from the signal quality reported by other terminal devices received by the second satellite network within the coverage area of ​​the second satellite network, as the access beam it accesses in the second satellite network.

[0146] For example, a beam index related to a identified signal quality reported within the coverage area may be the beam index of the signal corresponding to the identified signal quality parameter, and may be used by terminal equipment to determine the optimal access beam.

[0147] The specified signal quality may be determined based on the average signal quality and a specific reference quantity. For example, the specified signal quality may be the signal quality obtained by adding a specific reference quantity to the average signal quality or subtracting a specific reference quantity from the average signal quality.

[0148] The specified signal quality may be determined based on the maximum signal quality and a specific reference quantity. For example, the specified signal quality may be the signal quality obtained by subtracting a specific reference quantity from the maximum signal quality.

[0149] Selectively, the beam associated with the signal quality after adding a specific reference quantity to the reported average signal quality or subtracting a specific reference quantity from the reported average signal quality will be designated as the access beam for terminal equipment in the second satellite network.

[0150] Optionally, signal quality may also be called signal strength, and signal quality may be indicated by the aforementioned RSRP, RSRQ, RSSI, or at least one other parameter indicating signal quality.

[0151] For example, the average and maximum admission powers of terminal equipment other than terminal equipment in the second satellite network may be used to determine the transmit power of the terminal equipment. Further details will be discussed later with reference to Figure 7.

[0152] For example, if the first handover instruction is a no-RACH handover instruction, the instruction may include pre-assigned authorizations, access beam indexes and reserved resources associated with the SSB, providing the azimuth angle of the second satellite network relative to the terminal equipment based on the terminal equipment's location information, and one or more pieces of information among the following: the maximum signal strength in the coverage area received by the second satellite network such as RSRP, RSSI, the average signal strength in the coverage area received by the second satellite network such as RSRP, RSSI, the average value of the admission received power of other terminal equipment recognized by the second satellite network, the maximum value of the admission received power of other terminal equipment recognized by the second satellite network, and time-related parameters of the second satellite network.

[0153] As can be seen from Figure 4, in some handovers (e.g., handovers without RACH), terminal equipment can transmit information determining the first beam to the second satellite network after determining the second satellite network for the handover, thereby improving the success rate of the handover, so that the second satellite network can make more effective resource reservations. If resource reservations are indicated by UL authorization, UL authorization may be assigned by RRC signaling and / or PDCCH of the second satellite network to facilitate reception by terminal equipment.

[0154] To facilitate understanding, the following illustrative explanation will refer to two possible implementations shown in Figures 5 and 6. Figure 5 is a schematic flowchart in which a terminal device transmits first information to the second satellite network before receiving the first handover command. Figure 6 is a schematic flowchart in which a terminal device performs a handover without RACH.

[0155] Referring to Figure 5, in step S510, the terminal device transmits the first measurement report to the first satellite network.

[0156] In step S520, the first satellite network performs a handover decision to determine the second satellite network.

[0157] In step S530, the terminal device transmits the first information to the first satellite network. Based on the beam identification information of the second satellite network transmitted from the first satellite network, the terminal device can perform identification and measurement, generate and transmit the first information.

[0158] In step S540, the first satellite network sends a handover request to the second satellite network. The handover request includes first information for the second satellite network to determine the first beam.

[0159] In step S550, the second satellite network sends a handover request confirmation to the first satellite network. The handover request confirmation includes second information to instruct terminal equipment to use the first beam.

[0160] In step S560, the first satellite network transmits the first handover command to the terminal equipment.

[0161] In step S570, the terminal device transmits an initial uplink transmission to the second satellite network.

[0162] In Figure 5, the terminal device transmits the first information after the handover decision. For example, before the second satellite network transmits the first information for determining the first beam, the first satellite network can transmit the decision result of step S504 to the terminal device, thereby allowing the terminal device to determine the second satellite network.

[0163] Referring to Figure 6, in step S610, the terminal device transmits measurement control and report to the first satellite network.

[0164] In step S620, the first satellite network performs a handover decision (HO decision).

[0165] In step S630, the first satellite network sends a handover request (HO request) to the second satellite network.

[0166] In step S640, the second satellite network sends a handover request acknowledgment (HO request ACK) to the first satellite network.

[0167] In step S650, the first satellite network transmits RACH-less HO configuration information to the terminal equipment. The terminal equipment then sequentially activates timers T304 and T430.

[0168] In step S660, the terminal device sends an initial uplink transmission. This initial uplink transmission is sent based on available uplink permissions (RRC, MAC, PHY). The initial uplink transmission includes sending an RRCReconfigurationComplete message.

[0169] 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 a pre-assigned UL authorization. The terminal device stops timer T304.

[0170] The handover request confirmation in Figure 6 includes the second piece of information mentioned above, which allows the terminal equipment to determine whether the first beam or SSB is associated with the reserved resource of the second satellite network.

[0171] In some mobile scenarios, terminal equipment can receive a list of candidate satellite networks (which may be abbreviated as candidate networks) and a conditional handover command, and autonomously perform a handover (or attempt to handover) to a target satellite network. The target satellite network is one of the candidate networks that satisfies the handover conditions. This handover may be called a "conditional handover (CHO)," and the handover command associated with a conditional handover may be called a "conditional handover command." In the case of a conditional handover, terminal equipment can autonomously select a target network from among the candidate networks based on measurements of the candidate networks.

[0172] In NTN, when a CHO (Chief Handover Officer) is configured, the condition under which terminal equipment performs a satellite handover may be called the first condition. That is, a satellite handover is performed when the first condition is met.

[0173] When a no-RACH handover and CHO are configured, the first handover instruction must specify multiple candidate satellite networks and also specify multiple uplink authorizations. For example, the first handover instruction includes parameters for multiple candidate satellite networks, and the first resource in the first handover instruction includes multiple uplink authorizations. If the first condition is met, the terminal equipment can determine the second satellite network from among the multiple candidate satellite networks and determine the uplink authorization for the terminal equipment to perform the handover from among the multiple uplink authorizations.

[0174] For example, in a satellite handover using a no-RACH and CHO configuration, the first and second satellite networks need to direct timing coordination and selectable pre-assigned authorizations.

[0175] For example, the first satellite network may further receive third information transmitted from terminal equipment. The third information is information for indicating the first condition. The third information may include one or more of the following: handover conditions associated with at least one candidate satellite network based on SSB-RS; handover conditions associated with at least one candidate satellite network based on CSI-RS; measurement results / measurement information for at least one SSB-RS or CSI-RS; and at least one SSB-RS or CSI-RS associated with a non-conflict random access resource.

[0176] For example, the first satellite network can receive RRC reconstruction information from terminal equipment. The RRC reconstruction information may include signal measurement results of at least one target satellite network, and at least one SSB-RS, at least one CSI-RS, CHO execution conditions based on SSB, and CHO execution conditions based on CSI-RS associated with CHO execution.

[0177] The above explains the handover conditions for implementing RACH-less handover and CHO at NTN, and that terminal equipment can autonomously perform satellite handover when the conditions are met.

[0178] The above describes an example of a method for resolving the resource reservation problem with reference to Figure 4. In a handover process without RACH, because there is no transmission of the RACH preamble and no reception of random access responses, terminal equipment may set the initial transmit power to an inappropriate level due to incorrectly estimated path loss. For example, if terminal equipment receives information related to UL authorization, the terminal equipment may fall into a logical deadlock, and the handover may fail. For example, terminal equipment may decide to grant UL authorization, but because the transmit power is low, the network equipment cannot receive the uplink transmission, and the response message fails.

[0179] In a handover without RACH, if terminal equipment directly references the power control rules of the physical uplink shared channel (PUSCH) configured for initial transmit power of uplink transmission, problems may arise such as uncertain path loss and inability to apply power regulation.

[0180] For example, in RACH-less handovers, authorizations are pre-assigned or dynamically granted, and the determination of path loss is unclear or inaccurate. In NTN systems, the high elevation of satellites from the ground and the large area of ​​satellite coverage mean that inaccurate path loss estimations have a significant impact on power. In some scenarios, if the two handed-over satellites are of different types, their elevations from the ground will differ significantly, affecting the accuracy of path loss estimations.

[0181] For example, regarding PUSCH power adjustment and power control adjustment, the current specifications include conditions such as "if the UE receives a random access response message in response to the PRACH transmission," therefore, power adjustment and power control adjustment based on PRACH transmission power are not applicable to RACH-less handovers.

[0182] In summary, when implementing RACH-less handover in the NTN scenario, the problem to be solved is how terminal equipment determines the initial transmit power for uplink transmission using pre-allocated resources and how to improve the success rate of handover access for terminal equipment.

[0183] Furthermore, the problem of inappropriate transmit power due to the inability to trigger power control adjustment by PRACH because path loss is uncertain when introducing a RACH-less handover in the NTN system described above is only one example, and the embodiment of this application may be used in any type of handover scenario where path loss in transmit power is uncertain or power adjustment cannot be triggered.

[0184] To solve the above problems, an embodiment of the present invention provides an alternative method for NTN satellite handover. In this method, 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 network equipment corresponding to the second satellite network and the terminal equipment, thereby enabling the terminal equipment to determine a first power to perform uplink transmission to the second satellite network. Thus, the first power is advantageous in taking into account the communication or positional conditions of the second satellite network and improving the accuracy of the first power, thereby improving the handover success rate.

[0185] For ease of understanding, another method proposed by the embodiments of the present application will be described in detail below with reference to Figure 7. The method shown in Figure 7 is performed by terminal equipment. The method shown in Figure 7 may also be used for satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network. Note that, in order to simplify the explanation, terms explained in Figure 4 will not be repeated in Figure 7.

[0186] Referring to Figure 7, in step S710, the first handover instruction is received.

[0187] The first handover command received by the terminal equipment originates from the first satellite network. The first satellite network can determine the first handover command based on the handover request confirmation transmitted from the second satellite network.

[0188] The first handover instruction may be used to determine the first power at which the terminal device will perform an uplink transmission to the second satellite network. In some embodiments, the first handover instruction may be a no-RACH handover instruction. In some embodiments, the first handover instruction may be a handover instruction for another handover scheme without a random access response.

[0189] The uplink transmission by the terminal device to the second satellite network may be the initial uplink transmission described above, or it may be any other uplink transmission that the terminal device transmits to the second satellite network. For example, the uplink transmission is a push transmission.

[0190] Uplink transmissions may be transmitted using a first resource pre-configured by the second satellite network. In some embodiments, for push transmissions using reserved resources in no-RACH handovers, the SSB may be associated with the initial push transmission. That is, for pre-allocated initial push transmissions, the SSB can be determined before determining the push resource.

[0191] The first power may be the transmit power used by the terminal equipment to send the initial uplink transmission, or it may be the initial transmit power used by the terminal equipment to communicate with the second satellite network. As can be seen from the above, in NTN, if the terminal equipment performs a handover without executing a random access process and determines the first power without a random access response as a basis, problems may arise in the estimation of path loss or inefficient power adjustment. Therefore, in order to improve the accuracy of path loss estimation and the rationality of power adjustment, the first handover instruction may include relevant information for the terminal equipment to determine the initial transmit power.

[0192] To improve the accuracy of the first power, the first handover instruction 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 equipment. Information related to communication parameters within the coverage area of ​​the second satellite network may be carried in the handover request confirmation transmitted from the second satellite network.

[0193] Power-related information within the coverage area of ​​the second satellite network can indicate the power parameters that the second satellite network uses to communicate with terminal equipment within that area. When terminal equipment determines the first power based on these power parameters, it can obtain a power value that is more suitable for accessing the second satellite network, thereby improving the success rate of access.

[0194] In some embodiments, power-related information within the coverage area of ​​the second satellite network may include one or more parameters among the following: the average signal quality of some or all uplink beams accessed within the area; the maximum signal quality of some or all uplink beams accessed within the area; the transmit power transmitted by at least some terminal equipment accessed within the area through random access uplink channels; the average admission power of terminal equipment other than terminal equipment in the second satellite network; the maximum admission power of terminal equipment other than terminal equipment 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.

[0195] For example, power-related information may include beam signal quality associated with RACH-less handovers.

[0196] For example, the signal quality may be one or more of the aforementioned RSRP, RSRQ, and RSSI.

[0197] Some or all uplink beams accessed within the coverage area of ​​the second satellite network refer to some or all uplink beams within the coverage area received by the second satellite network. In some embodiments, some uplink beams may be uplink beams of other terminal equipment located closer to the terminal equipment's location.

[0198] For example, if the handover request confirmation includes the average value of the signal strength (e.g., RSRP) of some or all uplink beams within the coverage area received by the second satellite network, the terminal equipment can obtain this average value by the first handover instruction. Based on this average value, the terminal equipment can estimate the amount of transmit power required to reach that signal strength at its current location, which is the amount of first power for the terminal equipment to hand over to the second satellite network.

[0199] For example, if a handover request confirmation includes the maximum value of the signal strength (e.g., RSRP) of some or all uplink beams within the coverage area received by the second satellite network, the terminal equipment can obtain this maximum value by the first handover command. Based on this maximum value, the terminal equipment can estimate the amount of transmit power required to reach this signal strength at its current location, which is the amount of first power for the terminal equipment to hand over to the second satellite network. When the terminal equipment determines the first power based on the maximum value, the problem of the transmit power being too low and failing to receive a response can be effectively solved.

[0200] Beams associated with RACH-less handovers within the coverage area of ​​the second satellite network refer to beams associated with reserved RACH-less handovers within the coverage area received by the second satellite network. In some embodiments, these associated beams may be SSB beams. For example, a path loss reference signal for PUSCH transmission may be selected as the SSB reference signal for determining reserved PUSCH resources.

[0201] For example, if a handover request confirmation includes the signal strength (e.g., RSRP) of a beam associated with a reserved RACH-free handover in a coverage area received by the second satellite network, the terminal equipment can obtain this value by the first handover instruction. The terminal equipment can then estimate the magnitude of the transmit power required to reach this signal strength at its current location, based on the maximum value, as the magnitude of the first power for the terminal equipment to hand over to the second satellite network.

[0202] For example, for an initial push transmission based on dynamic grant (DG), the second satellite network can directly direct the SSB via PDCCH. Since there is no random access process, for power control of the initial push transmission, the path loss criterion may be the SSB associated with the initial push transmission.

[0203] The transmit power of random access uplink channels transmitted by at least some terminal equipment accessed within the coverage area of ​​the second satellite network refers to the power of the physical random access channel (PRACH) within the coverage area received by the second satellite network. In some embodiments, these parameters may be determined based on the initial nominal power of the PRACH. The initial nominal power of the PRACH transmit may be set in the RRC, as in the conventional case. In some embodiments, if the initial nominal power of the PRACH transmit is not set, these parameters may be determined as the initial target received power of the PRACH in the second satellite network. The PRACH is not initiated by terminal equipment performing a no-RACH handover, but may be read from the system information block (SIB) of the second satellite network.

[0204] For example, a terminal device can read the initial target received power of another terminal device's PRACH in the SIB1 of the second satellite network as a criterion for determining the first power.

[0205] For example, in a handover without RACH, since there is no random access process, the transmit power of the random access uplink channel may be the transmit power at least some terminal devices that transmit message A (msgA), or the transmit power at least some terminal devices that transmit message 3 (msg3). That is, the first power is determined based on the transmit power of message A and / or message 3 transmitted by other terminal devices. Examples of such examples include the average or maximum transmit power at which some terminal devices transmit message A. Alternatively, for example, the reference may be the average or maximum transmit power at which all terminal devices transmit message A.

[0206] The average or maximum admission power of terminal equipment other than terminal equipment in the second satellite network refers to the average or maximum admission power that the second satellite network allows other terminal equipment to access. For terminal equipment, the relevant parameters of admission power can serve as a benchmark for the first power. For example, if the service of terminal equipment needs to access the second satellite network in a timely manner, the first power may be equal to or close to the maximum admission power. Alternatively, for example, the first power may be equal to the average value for initial uplink transmission.

[0207] For example, terminal equipment other than terminal equipment may be some of the terminal equipment in the second satellite network, or all of the terminal equipment, and is not limited thereto.

[0208] For example, some terminal devices may be other terminal devices located geographically close to the terminal device.

[0209] The average or maximum path loss within the coverage area of ​​the second satellite network refers to the average or maximum path loss of network equipment corresponding to the second satellite network communicating with other terminal equipment, and may be used to determine the path loss in the first power.

[0210] In some embodiments, the determination of the first power may further require consideration of the maximum output power of the terminal equipment. The first power may be less than or equal to a certain percentage (e.g., 80%) of the maximum output power. Exemplarily, the first power is determined based on power-related information in the first handover instruction and the maximum output power of the terminal equipment. For example, if the maximum output power is less than the maximum value of the admission power, the first power can be determined by referring to the average value.

[0211] In step S720, based on the first handover instruction, the first power for uplink transmission to the second satellite network is determined. The above describes several possible embodiments of determining the first power in combination with the information in the first handover instruction, and these will not be repeated here. The calculation method for PUSCH transmission power is briefly described below.

[0212] The first handover instruction may further include relative position information between the second satellite corresponding to the second satellite network and the terminal equipment, which the terminal equipment uses to determine the path loss compensation coefficient in the second satellite network. The second satellite is the satellite corresponding to the second satellite network, and the first satellite is the satellite corresponding to the first satellite network.

[0213] The path loss of terminal equipment differs between the first and second satellite networks, and path loss is related to both distance and frequency. The path loss compensation coefficient for terminal equipment in the second satellite network may be used to compensate for the path loss in the second satellite network. For simplicity, the path loss compensation coefficient for terminal equipment in the first satellite network may be called the first path loss compensation coefficient, and the path loss compensation coefficient for the second satellite network may be called the second path loss compensation coefficient.

[0214] In some embodiments, the second path loss compensation coefficient may be carried in a first handover command transmitted from the first satellite network to the terminal equipment. That is, after the second satellite network has determined the second path loss compensation coefficient, it may be transmitted directly to the terminal equipment by the first handover command.

[0215] In some embodiments, relative position information may include the distance between the terminal device and the second satellite. Path loss can be estimated based on this distance parameter. This distance may be determined by the position coordinates of the terminal device and the position coordinates of the second satellite. Exemplarily, the position coordinates of the terminal device may be obtained by GNSS position information or by other means. The first satellite network may transmit the terminal device's position information to the second satellite network via a handover request message. The position information of the second satellite may be determined by satellite ephemeris information (ephemerisInfo).

[0216] In some embodiments, relative position information may include a directional angle between the terminal device and the second satellite. The directional angle may also be called an azimuth angle. The directional angle may be the angle between the line connecting the terminal device and the satellite and the perpendicular from the satellite to the ground, i.e., the angle between the terminal device and a point on the ground directly below the satellite. The directional angle may be determined based on the position of the terminal device and the position of the second satellite.

[0217] In some embodiments, the relationship between path loss from terminal equipment to the first satellite network and the second satellite network may be used to determine the second path loss compensation coefficient.

[0218] For example, the path loss compensation coefficient for a terminal device in the second satellite network may be determined by the direction angle of the terminal device in the first satellite network and the direction angle of the terminal device in the second satellite network. If the second path loss compensation coefficient is denoted by K, K can be calculated by the following formula.

[0219]

number

[0220] However, δ1 indicates the directional angle between the terminal device and the first satellite corresponding to the first satellite network, and δ2 indicates the directional angle between the terminal device and the second satellite corresponding to the second satellite network.

[0221] To facilitate understanding, the method for determining the second path loss compensation coefficient will be outlined below with reference to Figure 8. Referring to Figure 8, satellite 810 is the first satellite corresponding to the first satellite network, and satellite 820 is the second satellite corresponding to the second satellite network. Terminal equipment 830 performs a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network.

[0222] 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 a point on the ground directly below satellites 810 and 820 at this time, using the position coordinate information of terminal device 830.

[0223] The method for determining the second path loss compensation coefficient K has been explained above. Based on the value of K, the first power of the terminal equipment can be determined. For example, the first power P of the terminal equipment performing uplink transmission with the uplink bandwidth b of the carrier f of serving cell c. PUSCH,b,f,c This may be determined based on the following formula:

[0224]

number

[0225] However, i indicates the transmission opportunity, j indicates the index of the parameter set configuration, and q dindicates the index of the reference signal, l indicates the index of the power control adjustment state, and μ is related to the subcarrier interval.

number

number

number

number

number

number

number

[0226] Selectable,

number

[0227] Selectively, μ may be a subcarrier spacing configuration supported by the protocol, which can enable the adjustment of bandwidth resources with different subcarrier spacing configurations, thereby enabling corresponding power adjustments.

[0228] As mentioned above,

number

[0229] Selectable,

number

[0230] The terminal device can be selected as follows:

number

[0231] The terminal device can be selected as follows:

number

[0232]

number

[0233] Selectable,

number

[0234] Selectable,

number

[0235] The above describes how to determine the first power based on the second path loss compensation coefficient K. As can be seen from the above, the first handover instruction may be a no-RACH handover instruction. If the satellite handover is a no-RACH handover, the preamble power rampping counter described above may not be able to determine the power adjustment amount for the second satellite network. The power increase of the preamble power rampping counter is related to the PUSCH and / or PRACH of message A in the first satellite network. The PUSCH and / or PRACH of message A in the first satellite network use the same spatial domain transmit beam. However, the parameters in the second satellite network may not be relevant to the counter.

[0236] To solve this problem, a new power adjustment counter P may be used. The power adjustment counter P may be a counter that corresponds to no RACH and may be used to determine the amount of power adjustment in the first power. In some embodiments, the value of the power adjustment counter P may be related to a parameter that the terminal device uses to access the first satellite network. In some embodiments, the value of the power adjustment counter P may be related to the number of random accesses by the terminal device. Exemplarily, the value of the power adjustment counter P is the number of accesses by the terminal device to establish a connection with the first satellite network.

[0237] In some embodiments, the power adjustment amount of the first power may be further determined based on a power adjustment coefficient, for example, N, where the value of N is a positive integer greater than 1.

[0238] For example, the power adjustment coefficient N may be determined based on the service type of the terminal equipment. That is, N is related to the service type. For instance, the higher the quality of service (QoS) requirement, the larger the value of N may be.

[0239] For example, during the period when a handover occurs, the power adjustment amount on the first satellite network cannot be used continuously. To ensure that the terminal equipment can smoothly hand over to the second satellite network, the transmit power at this time needs to be relatively high. This may cause some interference to other nearby terminal equipment, but it can guarantee the success rate of access. After the terminal equipment transmits information that the handover was successful, that is, when the terminal equipment has already established a communication link with the second satellite network, the transmit power of the terminal equipment decreases accordingly. Even without receiving a TPC adjustment command in the PDCCH, the terminal equipment reduces its transmit power based on a new power adjustment counter.

[0240] The method for determining the power adjustment coefficient N has been explained above. Based on the value of N, the first power of the terminal equipment can be determined. For example, the first power P required for the terminal equipment to perform uplink transmission with the uplink bandwidth b of the carrier f of serving cell c is... PUSCH,b,f,c This may be determined based on the following formula:

[0241]

number

[0242] However, N represents the power adjustment coefficient, and N > 1. Other parameters have already been explained and will not be repeated here.

[0243] Optionally, the first power of the terminal equipment may take into account path loss and power adjustment. For example, the first power P for the terminal equipment to perform uplink transmission with the uplink bandwidth b of the carrier f of serving cell c. PUSCH,b,f,c This may be determined based on the following formula:

[0244]

number

[0245] However, K is the second path loss compensation coefficient, and N is the power adjustment coefficient.

[0246] The method embodiments of the present application have been described in detail above with reference to FIGS. 1 to 8. Hereinafter, the apparatus embodiments of the present application will be described in detail with reference to FIGS. 9 to 15. It should be understood that the description of the apparatus embodiments corresponds to the description of the method embodiments, and therefore, for parts not described in detail, reference may be made to the previous method embodiments.

[0247] FIG. 9 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 above-described terminal devices. The terminal device 900 shown in FIG. 9 includes a transmission unit 910 and a first reception unit 920.

[0248] The transmission unit 910 may be used to transmit first information, and the first information is used for the second satellite network to determine a first beam corresponding to the terminal device. The first beam includes one or more beams, and the first beam is related to a first resource and / or a second resource preconfigured by the second satellite network for satellite handover.

[0249] The first reception unit 920 may be used to receive a first handover command, and 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.

[0250] Optionally, the first handover command includes one or more pieces of information selected from: a permission pre-assigned by the second satellite network, a first resource pre-configured by the second satellite network, a beam index related to a synchronization signal block in the second satellite network, the maximum signal quality reported within the coverage area received by the second satellite network and the related beam index, the beam index related to the specified signal quality reported within the coverage area received by the second satellite network, the average value of the admission power of terminal devices other than the terminal device in the second satellite network, and the maximum value of the admission power of terminal devices other than the terminal device in the second satellite network. Optionally, the first information includes a plurality of first measurement results obtained by the terminal device measuring the reference signals of a plurality of beams of the second satellite network, and the plurality of first measurement results are used to determine the first beam.

[0251] Optionally, the first measurement result corresponding to the first beam is the maximum value among the plurality of first measurement results, or the maximum M values among the plurality of first measurement results.

[0252] Optionally, the first measurement result corresponding to the first beam is greater than a first threshold.

[0253] Optionally, the first resource is a reserved resource for satellite handover, the second resource is a scheduled uplink resource, and the uplink resource is used by the terminal device to perform satellite handover.

[0254] Optionally, after further transmitting the first information, the first receiving unit 920 is used to receive second information, the second information is used to indicate the first beam, the terminal device 900 further includes a second receiving unit, and after receiving the first handover command, the second receiving unit may be used to detect a downlink channel transmitted from the second satellite network based on the first beam.

[0255] Selectively, the first beam is indicated by an identifier of the reference signal associated with the first beam.

[0256] Selectively, the satellite handover is a no-RACH handover, the second satellite network is a satellite network that satisfies the no-RACH handover condition, the transmitting unit 910 is further used to transmit a first measurement report before transmitting first information, the first measurement report is used by the first satellite network to determine the second satellite network from among several candidate satellite networks, and the first measurement report includes several second measurement results in which terminal equipment measures reference signals of several candidate satellite networks.

[0257] Selectively, the second measurement result corresponding to the second satellite network is either the maximum value among multiple second measurement results, or one of multiple second measurement results that is greater than or equal to the second threshold.

[0258] Selectively, the reference signal includes SSB-RS and / or CSI-RS.

[0259] Optionally, the first beam is also used to carry one or more synchronization signal blocks for terminal equipment to perform satellite handover, and the index of one or more synchronization signal blocks is associated with the first resource.

[0260] Selectively, the first handover instruction is a no-RACH handover instruction.

[0261] Optionally, a satellite handover is performed if a first condition is met, the first handover instruction includes parameters for multiple candidate satellite networks, the first resource includes multiple uplink authorizations, and the terminal device 900 further includes a first decision unit and a second decision unit, the first decision unit may be used to determine a second satellite network from among multiple candidate satellite networks, and the second decision unit may be used to determine an uplink authorization from among multiple uplink authorizations for the terminal device to perform a handover.

[0262] Optionally, the transmitting unit 910 is used to transmit third information to a first satellite network, the third information is used to indicate the first condition, the third information includes one or more of the following: handover conditions associated with at least one candidate satellite network based on SSB-RS; handover conditions associated with at least one candidate satellite network based on CSI-RS; measurement results / measurement information for at least one SSB-RS or CSI-RS; and at least one SSB-RS or CSI-RS associated with a non-conflict random access resource.

[0263] Figure 10 is a schematic block diagram of a network device according to an embodiment of the present application. The network device 1000 may be any of the network devices corresponding to the first satellite network described above. The network device 1000 in Figure 10 includes a receiving unit 1010, a first transmitting unit 1020, and a second transmitting unit 1030.

[0264] The receiving unit 1010 may be used to receive first information transmitted from a terminal device.

[0265] The first transmitting unit 1020 may be used to transmit first information to a second satellite network, the first information being used by the second satellite network to determine a first beam corresponding to terminal equipment, the first beam comprising one or more beams, and the first beam relating to first and / or second resources pre-configured by the second satellite network for satellite handover.

[0266] The second transmission unit 1030 may be used to transmit a first handover command to a terminal device, which 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.

[0267] Optionally, the first handover instruction includes one or more of the following pieces of information: authorization pre-allocated by the second satellite network; first resources pre-configured by the second satellite network; beam index associated with synchronization signal blocks in the second satellite network; maximum signal quality in the coverage area received by the second satellite network; average signal quality in the coverage area received by the second satellite network; average admission power of non-terminal equipment in the second satellite network; and maximum admission power of non-terminal equipment in the second satellite network.

[0268] Selectively, the first resource is a reserved resource for satellite handover, and the second resource is a scheduled uplink resource, which is used by terminal equipment to perform satellite handover.

[0269] Optionally, the receiving unit 1010 may be used to receive second information transmitted from the second satellite network after further transmitting first information to the second satellite network, and the first transmitting unit 1020 may be used to transmit second information to terminal equipment, and the second information may be used to direct the first beam.

[0270] Selectively, the satellite handover is a no-RACH handover, the second satellite network is a satellite network that satisfies the no-RACH handover condition, the receiving unit 1010 is used to receive a first measurement report transmitted from the terminal equipment before receiving first information transmitted from the terminal equipment, the first measurement report is used by the first satellite network to determine the second satellite network that satisfies the no-RACH handover condition from among a plurality of candidate satellite networks, and the first measurement report includes a plurality of second measurement results in which the terminal equipment measures the reference signals of a plurality of candidate satellite networks.

[0271] Optionally, the second measurement result corresponding to the second satellite network is the maximum value among a plurality of second measurement results, or is one second measurement result greater than or equal to a second threshold among the plurality of second measurement results.

[0272] Optionally, the reference signal includes SSB-RS and / or CSI-RS.

[0273] Optionally, the first handover command is a handover command without RACH.

[0274] Optionally, the satellite handover is executed when a first condition is satisfied. The first handover command includes parameters of a plurality of candidate satellite networks and is further used for the receiving unit 1010 to receive third information transmitted from the terminal device. The third information is used to indicate the first condition and includes one or more pieces of information among a handover condition associated with at least one candidate satellite network based on SSB-RS, a handover condition associated with at least one candidate satellite network based on CSI-RS, 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.

[0275] FIG. 11 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 FIG. 11 includes a receiving unit 1110 and a first transmitting unit 1120.

[0276] The receiving unit 1110 may be used to receive first information transmitted from the first satellite network. The first information is used for the second satellite network to determine a first beam corresponding to the terminal device. The first beam includes one or more beams and is related to a first resource and / or a second resource preconfigured by the second satellite network for satellite handover.

[0277] The first transmitting unit 1120 may also be used to send a handover request confirmation to the first satellite network based on a handover request sent from the first satellite network, the handover request confirmation being used by the first satellite network to send a first handover command to terminal equipment, the first handover command being used to instruct terminal equipment to perform a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network.

[0278] Optionally, the first handover instruction includes one or more of the following pieces of information: authorization pre-allocated by the second satellite network; first resources pre-configured by the second satellite network; beam index associated with synchronization signal blocks in the second satellite network; maximum signal quality in the coverage area received by the second satellite network; average signal quality in the coverage area received by the second satellite network; average admission power of non-terminal equipment in the second satellite network; and maximum admission power of non-terminal equipment in the second satellite network.

[0279] Optionally, the first information includes multiple first measurement results obtained when a terminal device measures reference signals for multiple beams of the second satellite network, and these multiple first measurement results are used to determine the first beam.

[0280] Selectively, the first measurement result corresponding to the first beam is the maximum value among a plurality of first measurement results, or the maximum M values ​​among the plurality of first measurement results.

[0281] Selectively, the first measurement result corresponding to the first beam is greater than the first threshold.

[0282] Selectively, the first resource is a reserved resource for satellite handover, and the second resource is a scheduled uplink resource, which is used by terminal equipment to perform satellite handover.

[0283] Optionally, after receiving first information transmitted from the first satellite network, the first transmitting unit 1120 may be used to transmit second information to the first satellite network, the second information being used to indicate the first beam, and the network equipment 1100 may further include a second transmitting unit, which may be used to transmit a downlink channel based on the first beam after sending a handover request confirmation to the first satellite network.

[0284] Selectively, the first beam is indicated by an identifier of the reference signal associated with the first beam.

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

[0286] Optionally, the first beam is also used to carry one or more synchronization signal blocks for terminal equipment to perform satellite handover, and the index of one or more synchronization signal blocks is associated with the first resource.

[0287] Selectively, the first handover instruction is a no-RACH handover instruction.

[0288] Figure 12 is a schematic block diagram of another terminal device of 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 Figure 12 includes a receiving unit 1210 and a decision unit 1220.

[0289] The receiving unit 1210 may be used to receive a first handover command, which is used to instruct a terminal device to perform a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network, and which 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.

[0290] The decision unit 1220 may be used to determine a first power for uplink transmission to the second satellite network based on a first handover instruction.

[0291] Optionally, power-related information within the coverage area of ​​the second satellite network includes one or more parameters from the following: the average signal quality of some or all uplink beams accessed within the area; the maximum signal quality of some or all uplink beams accessed within the area; the transmit power transmitted by at least some terminal equipment accessed within the area through random access uplink channels; the average admission power of non-terminal equipment in the second satellite network; the maximum admission power of non-terminal equipment 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.

[0292] Selectively, the first power is determined based on power-related information and the maximum output power of the terminal equipment.

[0293] The selectable signal quality is one or more of RSRP, RSRQ, or RSSI.

[0294] Selectively, the transmit power transmitted by at least some terminal devices accessed within the region to send random access uplink channels includes one or more of the transmit power transmitted by at least some terminal devices to send message A and the transmit power transmitted by at least some terminal devices to send message 3.

[0295] Optionally, relative position information is used to determine the path loss compensation coefficient for the terminal device in the second satellite network, and the relative position information includes one or more pieces of information, such as the distance between the terminal device and the second satellite, and the azimuth angle between the terminal device and the second satellite.

[0296] Selectively, the path loss compensation coefficient is determined based on the directional angle between the terminal equipment and the second satellite, and the path loss compensation coefficient K is determined based on the following formula:

[0297]

number

[0298] However, δ1 indicates the directional angle between the terminal device and the first satellite corresponding to the first satellite network, and δ2 indicates the directional angle between the terminal device and the second satellite corresponding to the second satellite network.

[0299] Selectively, a first power P for the terminal device to perform uplink transmission with the uplink bandwidth b of the carrier f of serving cell c. PUSCH,b,f,c This is determined based on the following formula:

[0300]

number

[0301] However, i indicates the transmission opportunity, j indicates the index of the parameter set configuration, and q d indicates the index of the reference signal, l indicates the index of the power control adjustment state, and μ is related to the subcarrier interval.

number

number

number

number

number

number

number

[0302] Selectively, the first handover instruction is a no-RACH handover instruction, and the power adjustment amount for the first power is determined based on the no-RACH power adjustment counter, the value of which is related to the parameters by which the terminal equipment accesses the first satellite network.

[0303] Selectively, the value of the power adjustment counter is the number of access attempts by the terminal device to establish a connection with the first satellite network.

[0304] Selectively, the power adjustment amount is further determined based on a power adjustment coefficient, which is determined based on the service type of the terminal equipment.

[0305] Selectively, a first power P for the terminal device to perform uplink transmission with the uplink bandwidth b of the carrier f of serving cell c. PUSCH,b,f,c This is determined based on the following formula:

[0306]

number

[0307] However, N represents the power adjustment coefficient, and N > 1.

[0308] Selectively, a first power P for the terminal device to perform uplink transmission with the uplink bandwidth b of the carrier f of serving cell c. PUSCH,b,f,c This is determined based on the following formula:

number

[0309] However, K represents the second path loss compensation coefficient, and N represents the power adjustment coefficient.

[0310] Figure 13 is a schematic block diagram of further network equipment of an embodiment of the present invention. The network equipment 1300 may be any of the network equipment corresponding to the first satellite network described above. The network equipment 1300 shown in Figure 13 includes a decision unit 1310 and a transmission unit 1310.

[0311] The decision unit 1310 may also be used to determine a first handover command based on a handover request confirmation transmitted from the second satellite network, the first handover command being used to instruct terminal equipment to perform a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network, the first handover command including power-related information within the coverage area of ​​the second satellite network, and / or relative position information between the second satellite corresponding to the second satellite network and the terminal equipment.

[0312] The transmitting unit 1320 may also be used to transmit a first handover command to a terminal device, which is used to determine a first power for the terminal device to perform an uplink transmission to the second satellite network.

[0313] Optionally, power-related information within the coverage area of ​​the second satellite network includes one or more parameters from the following: the average signal quality of some or all uplink beams accessed within the area; the maximum signal quality of some or all uplink beams accessed within the area; the transmit power transmitted by at least some terminal equipment accessed within the area through random access uplink channels; the average admission power of non-terminal equipment in the second satellite network; the maximum admission power of non-terminal equipment 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.

[0314] Selectively, the first power is determined based on power-related information and the maximum output power of the terminal equipment.

[0315] The selectable signal quality is one or more of RSRP, RSRQ, or RSSI.

[0316] Selectively, the transmit power transmitted by at least some terminal devices accessed within the region to send random access uplink channels includes one or more of the transmit power transmitted by at least some terminal devices to send message A and the transmit power transmitted by at least some terminal devices to send message 3.

[0317] Optionally, relative position information is used to determine the path loss compensation coefficient for the terminal device in the second satellite network, and the relative position information includes one or more pieces of information, such as the distance between the terminal device and the second satellite, and the azimuth angle between the terminal device and the second satellite.

[0318] Optionally, the path loss compensation factor is determined based on the direction angle between the terminal device and the second satellite, and the path loss compensation factor K is determined based on the following formula:

[0319]

Number

[0320] However, 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 corresponding to the second satellite network.

[0321] Optionally, the first power P for the terminal device to perform uplink transmission with the uplink bandwidth b of the carrier f of the serving cell c PUSCH,b,f,c is determined based on the following formula:

[0322]

Number

[0323] However, i indicates the transmission opportunity, j indicates the index of the parameter set configuration, q d indicates the index of the reference signal, l indicates the index of the power control adjustment state, μ is related to the subcarrier spacing, and

Number

Number

Number

Number

number

number

number

[0324] Selectively, the first handover instruction is a no-RACH handover instruction, and the power adjustment amount for the first power is determined based on the no-RACH power adjustment counter, the value of which is related to the parameters by which the terminal equipment accesses the first satellite network.

[0325] Selectively, the value of the power adjustment counter is the number of access attempts by the terminal device to establish a connection with the first satellite network.

[0326] Selectively, the power adjustment amount is further determined based on a power adjustment coefficient, which is determined based on the service type of the terminal equipment.

[0327] Selectively, a first power P for the terminal device to perform uplink transmission with the uplink bandwidth b of the carrier f of serving cell c. PUSCH,b,f,c This is determined based on the following formula:

[0328]

number

[0329] However, N represents the power adjustment coefficient, and N > 1.

[0330] Selectively, a first power P for the terminal device to perform uplink transmission with the uplink bandwidth b of the carrier f of serving cell c.PUSCH,b,f,c This is determined based on the following formula:

[0331]

number

[0332] However, K represents the path loss compensation coefficient, and N represents the power adjustment coefficient.

[0333] Figure 14 is a schematic block diagram of yet another network device of an embodiment of the present invention. The network device 1400 may be any of the network devices corresponding to the second satellite network described above. The network device 1400 shown in Figure 14 includes a transmitting unit 1410.

[0334] The transmitting unit 1410 may also be used to transmit a handover request confirmation to the first satellite network, which is used to determine a first handover command, which is used to instruct terminal equipment to perform a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network.

[0335] The first handover instruction 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 equipment, and the first handover instruction is used to determine the first power for the terminal equipment to perform uplink transmission to the second satellite network.

[0336] Optionally, power-related information within the coverage area of ​​the second satellite network includes one or more parameters from the following: the average signal quality of some or all uplink beams accessed within the area; the maximum signal quality of some or all uplink beams accessed within the area; the transmit power transmitted by at least some terminal equipment accessed within the area through random access uplink channels; the average admission power of non-terminal equipment in the second satellite network; the maximum admission power of non-terminal equipment 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.

[0337] Selectively, the first power is determined based on power-related information and the maximum output power of the terminal equipment.

[0338] The selectable signal quality is one or more of RSRP, RSRQ, or RSSI.

[0339] Selectively, the transmit power transmitted by at least some terminal devices accessed within the region to send random access uplink channels includes one or more of the transmit power transmitted by at least some terminal devices to send message A and the transmit power transmitted by at least some terminal devices to send message 3.

[0340] Optionally, relative position information is used to determine the path loss compensation coefficient for the terminal device in the second satellite network, and the relative position information includes one or more pieces of information, such as the distance between the terminal device and the second satellite, and the azimuth angle between the terminal device and the second satellite.

[0341] Selectively, the path loss compensation coefficient is determined based on the directional angle between the terminal equipment and the second satellite, and the path loss compensation coefficient K is determined based on the following formula:

[0342]

number

[0343] However, δ1 indicates the directional angle between the terminal device and the first satellite corresponding to the first satellite network, and δ2 indicates the directional angle between the terminal device and the second satellite corresponding to the second satellite network.

[0344] Selectively, a first power P for the terminal device to perform uplink transmission with the uplink bandwidth b of the carrier f of serving cell c. PUSCH,b,f,c This is determined based on the following formula:

[0345]

number

[0346] However, i indicates the transmission opportunity, j indicates the index of the parameter set configuration, and q d indicates the index of the reference signal, l indicates the index of the power control adjustment state, and μ is related to the subcarrier interval.

number

number

number

number

number

number

number

[0347] Selectively, the first handover instruction is a no-RACH handover instruction, and the power adjustment amount for the first power is determined based on the no-RACH power adjustment counter, the value of which is related to the parameters by which the terminal equipment accesses the first satellite network.

[0348] Selectively, the value of the power adjustment counter is the number of access attempts by the terminal device to establish a connection with the first satellite network.

[0349] Selectively, the power adjustment amount is further determined based on a power adjustment coefficient, which is determined based on the service type of the terminal equipment.

[0350] Selectively, a first power P for the terminal device to perform uplink transmission with the uplink bandwidth b of the carrier f of serving cell c. PUSCH,b,f,c This is determined based on the following formula:

[0351]

number

[0352] However, N represents the power adjustment coefficient, and N > 1.

[0353] Selectively, a first power P for the terminal device to perform uplink transmission with the uplink bandwidth b of the carrier f of serving cell c. PUSCH,b,f,c This is determined based on the following formula:

[0354]

number

[0355] However, K represents the path loss compensation coefficient, and N represents the power adjustment coefficient.

[0356] Figure 15 is a schematic diagram of the structure of a communication device in an embodiment of the present application. The dashed lines in Figure 15 indicate that a unit or module is selectable. The device 1500 can be used to implement the method described in the above embodiment. The device 1500 may be a chip, terminal equipment, or network equipment.

[0357] The apparatus 1500 may include one or more processors 1510. The processors 1510 can support the apparatus 1500 in implementing the method described in the above embodiment. The processors 1510 may be general-purpose processors or dedicated processors. 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, a discrete gate or transistor logic device, a discrete hardware component, etc. The general-purpose processor may be a microprocessor, or the processor may be any conventional processor, etc.

[0358] The device 1500 may further include one or more memories 1520. A program is stored in the memory 1520, which is executed by the processor 1510 to cause the processor 1510 to perform the method described in the above embodiment. The memory 1520 may be independent of the processor 1510 or may be integrated with the processor 1510.

[0359] The device 1500 may further include a transceiver 1530. The processor 1510 can communicate with other devices or chips via the transceiver 1530. For example, the processor 1510 can send and receive data with other devices or chips via the transceiver 1530.

[0360] Embodiments of the present application further provide a computer-readable storage medium for storing a program. The computer-readable storage medium can be applied to a terminal device or network device according to an embodiment of the present application, and the program causes a computer to execute the program in the manner that is performed by the terminal device or network device in each embodiment of the present application.

[0361] The computer-readable storage medium may be any available medium that a computer can read, or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital video discs (DVDs)), or semiconductor media (e.g., solid state disks (SSDs)).

[0362] Embodiments of the present application further provide a computer program product configured to store a program. The computer program product includes a program. The computer program product can be applied to a terminal or network device according to an embodiment of the present application, and the program causes a computer to perform the same actions as those performed by the terminal or network device in each embodiment of the present application.

[0363] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware, or any combination thereof. If implemented by software, all or part of the embodiments may be implemented 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 into a computer and executed, all or part of the processes or functions described in the embodiments of the present application are generated. The computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable device. The computer instructions may 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 may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wire (e.g., coaxial cable, fiber optic cable, digital subscriber line (DSL)) or wirelessly (e.g., infrared, radio, microwave, etc.).

[0364] Embodiments of the present application further provide a computer program. The computer program can be applied to terminal equipment or network equipment according to embodiments of the present application, and the computer program causes a computer to execute the methods performed by the terminal equipment or network equipment in each embodiment of the present application.

[0365] In this application, the terms “system” and “network” may be used interchangeably. Furthermore, the terms used in this application are used solely to interpret the specific embodiments of this application and are not intended to limit this application. The terms “first,” “second,” “third,” and “fourth,” etc., in the specification, claims, and drawings of this application are used to distinguish different subjects, not to describe a specific order. Furthermore, the terms “include,” “have,” and any variations thereof are intended to cover non-exclusive inclusion.

[0366] In the embodiments of the present application, the “instruction” referred to may be a direct instruction, an indirect instruction, or an indication of a related relationship. For example, A instructing B may mean that A directly instructs B, for example, that B can be accessed by A; or A indirectly instructs B, for example, that A instructs C, and B can be instructed by C; or an indication of a related relationship between A and B.

[0367] In the embodiments of this application, the term "correspondence" may indicate a direct or indirect correspondence between the two, a related relationship between the two, or a relationship such as instruction and instruction, setting and setting.

[0368] In the embodiments of this application, “pre-defined” or “pre-configured” may be implemented by pre-storing in the device (including, for example, terminal devices and network devices) any other form that can indicate the corresponding code, table or related information, and this application does not limit the specific implementation. For example, pre-defined may refer to something defined in a protocol.

[0369] In the embodiments of this application, the term "protocol" may refer to a standard protocol in the field of communications, and may include, for example, the LTE protocol, the NR protocol, and related protocols applicable to future communications systems, but is not limited thereto.

[0370] In the embodiments of the present application, determining B in accordance with A does not mean determining B in accordance with A alone, but rather B may be determined in accordance with A and / or other information.

[0371] In the embodiments of this application, the term "and / or" simply describes the relationship between related objects and indicates that there are three types of relationships. For example, A and / or B includes the cases where only A exists, where A and B exist simultaneously, and where only B exists. In this specification, the symbol " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0372] In the various embodiments of the present application, the magnitude of the number of each process does not indicate the order of execution, and the execution order of each process should be determined based on its function and inherent logic, and does not constitute any limitation on the implementation processes of the embodiments of the present application.

[0373] In some embodiments relating to this application, it should be understood that the disclosed systems, apparatus and methods can be implemented in other forms. For example, the apparatus embodiments described above are merely illustrative, and for instance, the division of the units is merely one logic function division. In actual implementation, other division schemes may be employed, for example, multiple units or components may be combined or integrated into another system, or some features may be ignored or omitted. Furthermore, the mutual coupling, direct coupling or communication connection described or considered may also be an indirect coupling or communication connection via several interfaces, apparatus or units, and may be in the form of electrical, mechanical or other means.

[0374] The units described as separation members may or may not be physically separated, and the members referred to as units may or may not be physical units; that is, they may be located in one place or distributed among multiple network units. Some or all of the units can be selected as needed to achieve the objectives of the means of this embodiment.

[0375] Furthermore, each functional unit in each embodiment of the present application may be integrated into a single processing unit, each unit may exist physically separately, and two or more units may be integrated into a single unit.

[0376] Although specific embodiments of the present application have been described above, the scope of protection of the present application is not limited thereto. All modifications and substitutions that a person skilled in the art could easily conceive without departing from the technical scope disclosed herein should be included in the scope of protection of the present application. Accordingly, the scope of protection of the present application should be the same as the scope of protection of the claims described above. [Explanation of Symbols]

[0377] 100 Communication Systems 110 Network Equipment 120 terminal devices 200 NTN Systems 210 satellite 220 Service Links 230 Feeder Link 240 terminal devices 250 Gateways 260 Networks 300 Satellite Radio Access Networks 310 satellite 320 Service Links 330 Feeder Link 340 terminal devices 350 Gateways 360 Network 810 satellite 820 satellite 830 Terminal equipment

Claims

1. A method for non-terrestrial network satellite handover, applicable to satellite handover from a coverage area of ​​a first satellite network to a coverage area of ​​a second satellite network, wherein the method is A step of transmitting first information, wherein the first information is used by the second satellite network to determine a first beam corresponding to terminal equipment, and the first beam includes one or more beams. The steps include receiving a first handover command, wherein the first handover command is used to instruct the terminal device to perform the satellite handover, A method for non-terrestrial network satellite handover, characterized in that the first beam relates to a first and / or second resource pre-configured by the second satellite network for the satellite handover.

2. The first handover instruction is, The permission pre-allocated by the second satellite network, The first resource pre-configured by the second satellite network, The beam index related to the synchronization signal block in the second satellite network, The maximum signal quality and associated beam index reported within the coverage area received by the second satellite network, The beam index related to the identified signal quality reported within the coverage area received by the second satellite network, The average value of admission power of terminal equipment other than the terminal equipment in the second satellite network, The method according to claim 1, characterized in that it includes one or more pieces of information, such as the maximum value of admission power of terminal equipment other than the terminal equipment in the second satellite network.

3. The method according to 1 or 2, characterized in that the first information includes a plurality of first measurement results obtained by the terminal device measuring reference signals of a plurality of beams of the second satellite network, and the plurality of 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 the maximum value among the plurality of first measurement results, or the maximum M values ​​among the plurality of first measurement results.

5. The method according to the present invention, characterized in that the first measurement result corresponding to the first beam is greater than the 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 handover, the second resource is a scheduled uplink resource, and the uplink resource is used by the terminal equipment to perform the satellite handover.

7. After transmitting the first information, the method A step of receiving second information, wherein the second information is used to indicate the first beam, The method according to any one of claims 1 to 6, further comprising the step of detecting a downlink channel transmitted from the second satellite network based on the first beam after receiving the first handover command.

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

9. The satellite handover is a Random Access Channel (RACH)-free handover, the second satellite network is a satellite network that satisfies the RACH-free handover conditions, and before the step of transmitting the first information, the method The further step includes transmitting a first measurement report, the first measurement report being used by the first satellite network to determine the second satellite network from among a plurality of candidate satellite networks. The method according to any one of claims 1 to 8, characterized in that the first measurement report includes a plurality of second measurement results in which the terminal device measures the reference signals of the plurality of candidate satellite networks.

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

11. The method according to 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, wherein the first beam is further used to carry one or more synchronization signal blocks for the terminal equipment to perform the satellite handover, and the index of the one or more synchronization signal blocks is associated with the first resource.

13. The method according to any one of claims 1 to 12, characterized in that the first handover instruction is a no-RACH handover instruction.

14. The satellite handover is performed when a first condition is met, the first handover instruction includes parameters for a plurality of candidate satellite networks, the first resource includes a plurality of uplink permissions, and the method is The step of determining the second satellite network from among the plurality of candidate satellite networks, The method according to 13, further comprising the step of determining from among the plurality of uplink permissions that the terminal device will use to perform the satellite handover.

15. The process further includes the step of transmitting third information to the first satellite network, wherein the third information is used to indicate the first condition. The aforementioned third information is, Handover conditions associated with at least one candidate satellite network based on SSB-RS, Handover conditions associated with at least one candidate satellite network based on CSI-RS, At least one SSB-RS or CSI-RS measurement result / measurement information, The method according to 14, characterized by including information on one or more SSB-RS or CSI-RS associated with a non-conflict random access resource.

16. A method for non-terrestrial network satellite handover, applicable to satellite handover from a coverage area of ​​a first satellite network to a coverage area of ​​a second satellite network, wherein the method is A step of receiving first information transmitted from a terminal device, 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, The steps include transmitting the first information to the second satellite network, The steps include transmitting a first handover command to the terminal device, wherein the first handover command is used to instruct the terminal device to perform the satellite handover, A method for non-terrestrial network satellite handover, characterized in that the first beam relates to a first and / or second resource pre-configured by the second satellite network for the satellite handover.

17. The first handover instruction is, The permission pre-allocated by the second satellite network, The first resource pre-configured by the second satellite network, The beam index related to the 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 admission power of terminal equipment other than the terminal equipment in the second satellite network, The method according to 16, characterized in that it includes one or more pieces of information, such as the maximum value of admission power of terminal equipment other than the terminal equipment in the second satellite network.

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

19. After the step of transmitting the first information to the second satellite network, the method The steps include receiving second information transmitted from the second satellite network, The method according to any one of claims 16 to 18, further comprising the step of transmitting the second information to the terminal device, wherein the second information is used to direct the first beam.

20. The satellite handover is a Random Access Channel (RACH)-free handover, the second satellite network is a satellite network that satisfies the RACH-free handover conditions, and before the step of receiving the first information transmitted from the terminal device, the method The process further includes the step of receiving a first measurement report transmitted from a terminal device, wherein the first measurement report is used to determine the second satellite network from among a plurality of candidate satellite networks that satisfies the RACH-free handover condition, The method according to any one of claims 16 to 19, characterized in that the first measurement report includes a plurality of second measurement results in which the terminal device measures the reference signals of the plurality of candidate satellite networks.

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

22. The method according to 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 instruction is a no-RACH handover instruction.

24. The satellite handover is performed when a first condition is met, the first handover instruction includes parameters for a plurality of candidate satellite networks, and the method is The step further includes receiving third information transmitted from the terminal device, the third information being used to indicate the first condition, The aforementioned third information is, Handover conditions associated with at least one candidate satellite network based on SSB-RS, Handover conditions associated with at least one candidate satellite network based on CSI-RS, At least one SSB-RS or CSI-RS measurement result / measurement information, The method according to 23, characterized in that it includes information on one or more SSB-RS or CSI-RS associated with a non-conflict random access resource.

25. A method for non-terrestrial network satellite handover, applicable to satellite handover from a coverage area of ​​a first satellite network to a coverage area of ​​a second satellite network, wherein the method is A step of receiving first information transmitted from the first satellite network, 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 includes one or more beams. The steps include: transmitting a handover request confirmation to the first satellite network based on a handover request transmitted from the first satellite network, wherein the handover request confirmation is used by the first satellite network to transmit a first handover command to the terminal equipment, and the first handover command is used to instruct the terminal equipment to perform the satellite handover; A method for non-terrestrial network satellite handover, characterized in that the first beam relates to a first and / or second resource pre-configured by the second satellite network for the satellite handover.

26. The first handover instruction is, The permission pre-allocated by the second satellite network, The first resource pre-configured by the second satellite network, The beam index related to the 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 admission power of terminal equipment other than the terminal equipment in the second satellite network, The method according to 25, characterized in that it includes one or more pieces of information, such as the maximum value of admission power of terminal equipment other than the terminal equipment in the second satellite network.

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

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

29. The method according to 27, characterized in that the first measurement result corresponding to the first beam is greater than the 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 handover, the second resource is a scheduled uplink resource, and the uplink resource is used by the terminal equipment to perform the satellite handover.

31. After the step of receiving the first information transmitted from the first satellite network, the method, A step of transmitting second information to the first satellite network, wherein the second information is used to indicate the first beam, The method according to any one of claims 25 to 30, further comprising the steps of transmitting the handover request confirmation to the first satellite network, and then transmitting a downlink channel based on the first beam.

32. The method according to 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 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 further used to carry one or more synchronization signal blocks for the terminal equipment to perform the satellite handover, and the index of the one or more synchronization signal blocks is related to the first resource.

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

36. Terminal device, A transmitting unit for transmitting first information, wherein the first information is used by a second satellite network to determine a first beam corresponding to the terminal equipment, and the first beam includes one or more beams. A first receiving unit for receiving a first handover command, the first handover command being used to instruct a terminal device to perform a satellite handover from the coverage area of ​​a first satellite network to the coverage area of ​​a second satellite network, Terminal equipment characterized in that the first beam relates to a first resource and / or a second resource pre-configured by the second satellite network for the satellite handover.

37. The first handover instruction is, The permission pre-allocated by the second satellite network, The first resource pre-configured by the second satellite network, The beam index related to the synchronization signal block in the second satellite network, The maximum signal quality and associated beam index reported within the coverage area received by the second satellite network, The beam index related to the identified signal quality reported within the coverage area received by the second satellite network, The average value of admission power of terminal equipment other than the terminal equipment in the second satellite network, The terminal device according to claim 36, characterized in that it includes one or more pieces of information, such as the maximum value of 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, wherein the first information includes a plurality of first measurement results obtained by the terminal device measuring reference signals of a plurality of beams of the second satellite network, and the plurality of 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 the maximum value among the plurality of first measurement results, or the maximum M values ​​among the plurality of first measurement results.

40. The terminal device according to claim 38, characterized in that the first measurement result corresponding to the first beam is greater than the 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 handover, the second resource is a scheduled uplink resource, and the uplink resource is used by the terminal device to perform the satellite handover.

42. The first receiving unit is used to receive second information after transmitting the first information, and the second information is used to indicate the first beam. The aforementioned terminal device is The terminal device according to any one of claims 36 to 41, further comprising a second receiving unit for detecting a downlink channel transmitted from the second satellite network based on the first beam after receiving the first handover 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 satellite handover is a Random Access Channel (RACH)-free handover, the second satellite network is a satellite network that satisfies the RACH-free handover conditions, the transmitting unit is used to transmit a first measurement report before transmitting the first information, the first measurement report is used by the first satellite network to determine the second satellite network from among a plurality of candidate satellite networks, The terminal device according to any one of claims 36 to 43, characterized in that the first measurement report includes a plurality of second measurement results in which the terminal device measures the reference signals of the plurality of 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 the maximum value among the plurality of second measurement results, or one of the plurality of second measurement results that is equal to or greater than the 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 status information reference signal (CSI-RS).

47. The terminal device according to any one of claims 36 to 46, wherein the first beam is further used to carry one or more synchronization signal blocks for the terminal device to perform the satellite handover, and the index of the one or more synchronization signal blocks is related to the first resource.

48. The terminal device according to any one of claims 36 to 47, characterized in that the first handover instruction is a no-RACH handover instruction.

49. The satellite handover is performed when a first condition is met, the first handover instruction includes parameters for a plurality of candidate satellite networks, the first resource includes a plurality of uplink permissions, and the terminal equipment is A first decision unit for determining the second satellite network from among the plurality of candidate satellite networks, The terminal device according to claim 48, further comprising a second decision unit for determining from among the plurality of uplink permissions that the terminal device will use to perform the satellite handover.

50. The transmission unit is further used to transmit third information to the first satellite network, and the third information is used to indicate the first condition. The aforementioned third information is, Handover conditions associated with at least one candidate satellite network based on SSB-RS, Handover conditions associated with at least one candidate satellite network based on CSI-RS, At least one SSB-RS or CSI-RS measurement result / measurement information, The terminal device according to claim 49, characterized in that it includes information on one or more SSB-RS or CSI-RS associated with a non-conflict random access resource.

51. Network equipment, wherein the network equipment is network equipment corresponding to a first satellite network, and the network equipment is A receiving unit for receiving first information transmitted from a terminal device, A first transmitting unit for transmitting the first information to a second satellite network, wherein the first information is used by the second satellite network to determine a first beam corresponding to the terminal equipment, and the first beam includes one or more beams. A second transmitting unit for transmitting 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 the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network, Network equipment characterized in that the first beam relates to a first resource and / or a second resource pre-configured by the second satellite network for the satellite handover.

52. The first handover instruction is, The permission pre-allocated by the second satellite network, The first resource pre-configured by the second satellite network, The beam index related to the 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 admission power of terminal equipment other than the terminal equipment in the second satellite network, The network device according to claim 51, characterized in that it includes one or more pieces of information, such as the maximum value of admission power of terminal devices other than the terminal device in the second satellite network.

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

54. The network device according to any one of claims 51 to 53, wherein the receiving unit further transmits the first information to the second satellite network and then receives the second information transmitted from the second satellite network, the first transmitting unit further transmits the second information to the terminal equipment, and the second information is used to direct the first beam.

55. The satellite handover is a Random Access Channel (RACH)-free handover, the second satellite network is a satellite network that satisfies the RACH-free handover conditions, the receiving unit is used to receive a first measurement report transmitted from the terminal device before receiving the first information transmitted from the terminal device, the first measurement report is used by the first satellite network to determine the second satellite network from among a plurality of candidate satellite networks, The network device according to any one of claims 51 to 54, characterized in that the first measurement report includes a plurality of second measurement results in which the terminal device measures the reference signals of the plurality of 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 the maximum value among the plurality of second measurement results, or one of the plurality of second measurement results that is equal to or greater than the 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 instruction is a no-RACH handover instruction.

59. The satellite handover is performed when a first condition is met, the first handover command includes parameters for a plurality of candidate satellite networks, the receiving unit is further used to receive third information transmitted from the terminal equipment, and the third information is used to indicate the first condition. The aforementioned third information is, Handover conditions associated with at least one candidate satellite network based on SSB-RS, Handover conditions associated with at least one candidate satellite network based on CSI-RS, At least one SSB-RS or CSI-RS measurement result / measurement information, The network device according to claim 58, characterized in that it includes information on one or more SSB-RS or CSI-RS associated with a non-conflict random access resource.

60. Network equipment, wherein the network equipment is network equipment corresponding to the second satellite network, and the network equipment is A receiving unit for receiving first information transmitted from a first satellite network, wherein the first information is used by the second satellite network to determine a first beam corresponding to terminal equipment, and the first beam includes one or more beams. A first transmitting unit for transmitting a handover request confirmation to the first satellite network based on a handover request transmitted from the first satellite network, wherein the handover request confirmation is used by the first satellite network to transmit a first handover command to the terminal equipment, and the first handover command is used to instruct the terminal equipment to perform a satellite handover from the coverage area of ​​the first satellite network to the coverage area of ​​the second satellite network, Network equipment characterized in that the first beam relates to a first resource and / or a second resource pre-configured by the second satellite network for the satellite handover.

61. The first handover instruction is, The permission pre-allocated by the second satellite network, The first resource pre-configured by the second satellite network, The beam index related to the synchronization signal block in the second satellite network, The maximum signal quality and associated beam index reported within the coverage area received by the second satellite network, The beam index related to the identified signal quality reported within the coverage area received by the second satellite network, The average value of admission power of terminal equipment other than the terminal equipment in the second satellite network, The network device according to claim 60, characterized in that it includes one or more pieces of information, including the maximum value of admission power of terminal devices other than the terminal device in the second satellite network.

62. The network device according to claim 61, wherein the first information includes a plurality of first measurement results obtained by the terminal device measuring reference signals of a plurality of beams of the second satellite network, and the plurality of first measurement results are used to determine the first beam.

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

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

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

66. The first transmitting unit is used to transmit second information to the first satellite network after receiving first information transmitted from the first satellite network, and the second information is used to direct the first beam. The aforementioned network equipment is The network equipment according to any one of claims 60 to 65, further comprising a second transmitting unit for transmitting a downlink channel based on the first beam after transmitting the handover 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 status information reference signal (CSI-RS).

69. The network device according to any one of claims 60 to 68, wherein the first beam is further used to carry one or more synchronization signal blocks for the terminal device to perform the satellite handover, and the index of the one or more synchronization signal blocks is related to the first resource.

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

71. A communication device comprising a memory for storing a program and a processor for calling the program in the memory and executing the method according to any one of claims 1 to 35.

72. An apparatus comprising a processor for calling a program from memory and executing the method described in any one of claims 1 to 35.

73. A chip characterized by including a processor that causes a device on which the chip is mounted to execute the method described in any one of claims 1 to 35 by calling a program from memory.

74. A computer-readable storage medium characterized in that it stores a program for causing a computer to execute the method described in any one of claims 1 to 35.

75. A computer program product characterized by including a program that causes a computer to execute the method described in any one of claims 1 to 35.

76. A computer program characterized by causing a computer to execute the method described in any one of claims 1 to 35.

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