Wireless communication method, terminal device and network device

Abstract

Provided in the present application are a wireless communication method, a terminal device, and a network device, which are helpful for solving the problem of synchronization signal conflicts caused by PCI being unchanged when a terminal device performs satellite switching. The method comprises: a terminal device receives a first switching command, the first switching command being used for instructing the terminal device to perform switching from a first satellite to a second satellite; and the terminal device respectively detects a first synchronization signal and a second synchronization signal in a first resource domain and a second resource domain, wherein the first resource domain and the second resource domain are determined according to first information, the first synchronization signal is related to the first satellite, and the second synchronization signal is used for the terminal device to synchronize with the second satellite.

Description

Method, terminal equipment and network equipment for wireless communication Technical Field

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

[0002] In certain scenarios of non-terrestrial network (NTN) systems, when a terminal device's serving satellite changes, the physical cell identifier (PCI) of the serving cell remains unchanged. In these scenarios, when the terminal device switches its serving satellite, synchronization signals from different satellites with the same PCI may conflict, affecting handover efficiency.

[0003] Summary of the Invention

[0004] The present application provides a method, terminal device, and network device for wireless communication. The following describes various aspects of the embodiments of the present application.

[0005] In a first aspect, a method for wireless communication is provided, including: a terminal device receiving a first switching command, wherein the first switching command is used to instruct the terminal device to perform a switch from a first satellite to a second satellite; the terminal device detects a first synchronization signal and a second synchronization signal in a first resource domain and a second resource domain, respectively; wherein the first resource domain and the second resource domain are determined based on first information, the first synchronization signal is related to the first satellite, and the second synchronization signal is used for the terminal device to synchronize with the second satellite.

[0006] In a second aspect, a method for wireless communication is provided, including: a network device sends a first switching command to a terminal device, the first switching command being used to instruct the terminal device to perform a switch from a first satellite to a second satellite; wherein a second synchronization signal is used for the terminal device to synchronize with the second satellite, the first synchronization signal is related to the first satellite, a first resource domain and a second resource domain are respectively used by the terminal device to detect the first synchronization signal and the second synchronization signal, and the first resource domain and the second resource domain are determined based on first information.

[0007] According to a third aspect, a terminal device is provided, comprising: a receiving unit for receiving a first switching command, wherein the first switching command is used to instruct the terminal device to perform a switch from a first satellite to a second satellite; and a detection unit for detecting a first synchronization signal and a second synchronization signal in a first resource domain and a second resource domain, respectively; wherein the first resource domain and the second resource domain are determined based on first information, the first synchronization signal is related to the first satellite, and the second synchronization signal is used for synchronizing the terminal device with the second satellite.

[0008] In a fourth aspect, a network device is provided, comprising: a sending unit for sending a first switching command to a terminal device, wherein the first switching command is used to instruct the terminal device to perform a switch from a first satellite to a second satellite; wherein the second synchronization signal is used for the terminal device to synchronize with the second satellite, the first synchronization signal is related to the first satellite, the first resource domain and the second resource domain are respectively used by the terminal device to detect the first synchronization signal and the second synchronization signal, and the first resource domain and the second resource domain are determined based on the first information.

[0009] In a fifth aspect, a communication device is provided, comprising a memory and a processor, wherein the memory is used to store a program, and the processor is used to call the program in the memory to execute the method described in the first aspect or the second aspect.

[0010] In a sixth aspect, a device is provided, comprising a processor for calling a program from a memory to execute the method as described in the first aspect or the second aspect.

[0011] In a seventh aspect, a chip is provided, comprising a processor for calling a program from a memory so that a device equipped with the chip executes the method described in the first aspect or the second aspect.

[0012] In an eighth aspect, a computer-readable storage medium is provided, on which a program is stored, wherein the program enables a computer to execute the method as described in the first aspect or the second aspect.

[0013] In a ninth aspect, a computer program product is provided, comprising a program, wherein the program enables a computer to execute the method as described in the first aspect or the second aspect.

[0014] In a tenth aspect, a computer program is provided, which enables a computer to execute the method as described in the first aspect or the second aspect.

[0015] After receiving the first handover command, the terminal device in the embodiment of the present application can determine, based on the first information, the first resource domain and the second resource domain for detecting the first synchronization signal and the second synchronization signal, respectively. The first synchronization signal is associated with the first satellite, and the second synchronization signal is used to synchronize the terminal device with the second satellite. Thus, even if the first synchronization signal and the second synchronization signal carry the same PCI, the terminal device can detect synchronization signals from different satellites in different resource domains, thereby determining the second synchronization signal and performing handover. Based on the determination of different resource domains, the interference of the first synchronization signal on the handover process can be effectively avoided or reduced, thereby improving handover efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG1 is a wireless communication system used in an embodiment of the present application.

[0017] FIG2 is an NTN system used in an embodiment of the present application.

[0018] FIG3 is another NTN system applied in an embodiment of the present application.

[0019] FIG4 is a schematic diagram of satellite switching with unchanged PCI in the NTN system.

[0020] FIG5 is a flow chart of a method for wireless communication provided in an embodiment of the present application.

[0021] FIG6 is a schematic diagram of the time domain position of the synchronization signal.

[0022] FIG7 is a schematic diagram of a possible implementation manner of determining the first offset.

[0023] FIG8 is a schematic diagram of another possible implementation manner of determining the first offset.

[0024] FIG9 is a flowchart of a possible implementation of the method shown in FIG5 .

[0025] FIG10 is a schematic structural diagram of a terminal device provided in an embodiment of the present application.

[0026] FIG11 is a schematic structural diagram of a network device provided in an embodiment of the present application.

[0027] FIG12 is a schematic structural diagram of a communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0028] The following will describe the technical solutions in the embodiments of this application in conjunction with the drawings in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of the embodiments. With respect to the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0029] The embodiments of the present application can be applied to various communication systems. For example, the embodiments of the present application can be applied to global system of mobile communication (GSM) system, code division multiple access (CDMA) system, wideband code division multiple access (WCDMA) system, general packet radio service (GPRS), long term evolution (LTE) system, advanced long term evolution (LTE-A) system, new radio (NR) system, NR system evolution system, LTE on unlicensed spectrum (LTE-based access to unlicensed spectrum, LTE-U) system, NR on unlicensed spectrum (NR-based access to unlicensed spectrum, NR-U) system, universal mobile telecommunication system (UMTS), wireless local area networks (WLAN), wireless fidelity (WiFi), fifth generation communication (5th-generation, 5G) system. The embodiments of the present application can also be applied to other communication systems, such as future communication systems. The future communication system may be, for example, a sixth-generation (6G) mobile communication system or a satellite communication system.

[0030] Traditional communication systems support a limited number of connections and are easy to implement. However, with the development of communication technology, communication systems can not only support traditional cellular communications, but also support one or more other types of communications. For example, a communication system can support one or more of the following communications: device to device (D2D) communication, machine to machine (M2M) communication, machine type communication (MTC), enhanced machine type communication (eMTC), vehicle to vehicle (V2V) communication, and vehicle to everything (V2X) communication, etc. The embodiments of the present application can also be applied to communication systems that support the above-mentioned communication methods.

[0031] The communication system in the embodiment of the present application can be applied to a carrier aggregation (CA) scenario, a dual connectivity (DC) scenario, and a standalone (SA) networking scenario.

[0032] The communication system in the embodiments of the present application can be applied to unlicensed spectrum. The unlicensed spectrum can also be considered a shared spectrum. Alternatively, the communication system in the embodiments of the present application can also be applied to licensed spectrum. The licensed spectrum can also be considered a dedicated spectrum.

[0033] The embodiments of the present application can be applied to terrestrial networks (TN) systems as well as NTN systems. As an example, the NTN system may include a 4G-based NTN system, an NR-based NTN system, an Internet of Things (IoT)-based NTN system, and a narrowband Internet of Things (NB-IoT)-based NTN system.

[0034] A communication system may include one or more terminal devices. The terminal devices mentioned in the embodiments of the present application may also be referred to as user equipment (UE), access terminal, subscriber unit, subscriber station, mobile station, mobile station (MS), mobile terminal (MT), remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device, etc.

[0035] In some embodiments, the terminal device may be a station (ST) in a WLAN. In some embodiments, the terminal device may be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA) device, a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a wearable device, a terminal device in a next-generation communication system (e.g., a NR system), or a terminal device in a future-evolved public land mobile network (PLMN) network.

[0036] In some embodiments, the terminal device may be a device that provides voice and / or data connectivity to a user. For example, the terminal device may be a handheld device or an in-vehicle device with wireless connection capabilities. As some specific examples, the terminal device may be a mobile phone, a tablet computer, a laptop computer, a PDA, a mobile internet device (MID), a wearable device, a virtual reality (VR) device, an augmented reality (AR) device, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical surgery, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, etc.

[0037] In some embodiments, the terminal device can be deployed on land. For example, the terminal device can be deployed indoors or outdoors. In some embodiments, the terminal device can be deployed on the water, such as on a ship. In some embodiments, the terminal device can be deployed in the air, such as on an airplane, a balloon, or a satellite.

[0038] In addition to the terminal device, the communication system may also include one or more network devices. The network device in the embodiment of the present application may be a device for communicating with the terminal device, and the network device may also be referred to as an access network device or a radio access network device. The network device may be, for example, a base station. The network device in the embodiment of the present application may refer to a radio access network (RAN) node (or device) that connects the terminal device to a wireless network. The base station can broadly cover various names as follows, or be replaced with the following names, such as: NodeB, evolved NodeB (eNB), next generation NodeB (gNB), relay station, access point, transmission point (transmitting and receiving point, TRP], transmitting point (transmitting point, TP]), master station MeNB, secondary station SeNB, multi-standard radio (MSR) node, home base station, network controller, access node, wireless node, access point (AP), transmission node, transceiver node, baseband unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (distributed unit, DU), positioning node, etc. The base station can be a macro base station, a micro base station, a relay node, a donor node or the like, or a combination thereof. The base station can also refer to a communication module, a modem or a chip used to be set in the aforementioned equipment or device. The base station can also be a mobile switching center and a device that performs the base station function in D2D, V2X, and M2M communications, a network side device in a 6G network, a device that performs the base station function in a future communication system, etc. The base station can support networks with the same or different access technologies. The embodiments of the present application do not limit the specific technology and specific device form adopted by the network equipment.

[0039] Base stations can be fixed or mobile. For example, a helicopter or drone can be configured to act as a mobile base station, and one or more cells can move based on the location of the mobile base station. In other examples, a helicopter or drone can be configured to act as a device that communicates with another base station.

[0040] In some deployments, the network device in the embodiments of the present application may refer to a CU or a DU, or the network device may include a CU and a DU. The gNB may also include an AAU.

[0041] By way of example and not limitation, in embodiments of the present application, a network device may be mobile, for example, a mobile device. In some embodiments of the present application, the network device may be a satellite or balloon station. In some embodiments of the present application, the network device may also be a base station located on land, water, or the like.

[0042] In an embodiment of the present application, the network device can provide services for a cell, and the terminal device communicates with the network device through the transmission resources used by the cell (for example, frequency domain resources, or spectrum resources). The cell can be a cell corresponding to the network device (for example, a base station). The cell can belong to a macro base station or a base station corresponding to a small cell. The small cells here may include: metro cells, micro cells, pico cells, femto cells, etc. These small cells have the characteristics of small coverage and low transmission power, and are suitable for providing high-speed data transmission services.

[0043] For example, Figure 1 is a schematic diagram of the architecture of a communication system provided in an embodiment of the present application. As shown in Figure 1, communication system 100 may include network device 110, which may be a device that communicates with terminal device 120 (or referred to as a communication terminal). Network device 110 may provide communication coverage for a specific geographic area and may communicate with terminal devices within the coverage area.

[0044] Figure 1 exemplarily shows a network device and two terminal devices. In some embodiments of the present application, the communication system 100 may include multiple network devices and each network device may include other numbers of terminal devices within its coverage area, which is not limited in the embodiments of the present application.

[0045] For example, Figure 2 illustrates an architecture diagram of the aforementioned NTN system. NTN system 200 in Figure 2 utilizes satellite 210 as an aerial platform. As shown in Figure 2, the satellite radio access network includes satellite 210, service link 220, feeder link 230, terminal equipment 240, gateway (GW) 250, and network 260, including base stations and a core network.

[0046] Satellite 210 is a spacecraft based on a space platform. Service link 220 refers to the link between satellite 210 and terminal device 240. Feeder link 230 refers to the link between gateway 250 and satellite 210. Earth-based gateway 250 connects satellite 210 to a base station or core network, depending on the architecture selected.

[0047] The NTN architecture shown in Figure 2 is a bent-pipe transponder architecture. In this architecture, a base station is located on Earth behind gateway 250, with satellite 210 acting as a relay. Satellite 210 operates as a relay, forwarding signals from feeder link 230 to service link 220, or vice versa. In other words, satellite 210 does not function as a base station, and communications between terminal device 240 and base stations in network 260 can be relayed through satellite 210.

[0048] Figure 3 illustrates another NTN system architecture. As shown in Figure 3, satellite radio access network 300 includes satellite 310, service link 320, feeder link 330, terminal equipment 340, gateway 350, and network 360. Unlike Figure 2, satellite 310 has a base station 312, while network 360 behind gateway 350 consists solely of a core network.

[0049] The NTN architecture shown in Figure 3 is a regenerative transponder architecture. In this architecture, satellite 310 carries base station 312, which can be directly connected to the Earth-based core network via a link. Satellite 310 functions as a base station, and terminal device 340 can communicate directly with satellite 310. Therefore, satellite 310 can be referred to as a network device.

[0050] The communication system of the architecture shown in Figures 2 and 3 may include multiple network devices, and each network device may include other number of terminal devices within its coverage area, which is not limited in the embodiments of the present application.

[0051] In an embodiment of the present application, any of the communication systems shown in Figures 1 to 3 may also include other network entities such as a mobility management entity (MME) and an access and mobility management function (AMF), but this embodiment of the present application does not limit this.

[0052] It should be understood that in the embodiments of the present application, a device having a communication function in a network / system may be referred to as a communication device. Taking the communication system 100 shown in FIG1 as an example, the communication device may include a network device 110 and a terminal device 120 having a communication function. The network device 110 and the terminal device 120 may be the specific devices described above and will not be described in detail here. The communication device may also include other devices in the communication system 100, such as a network controller, a mobility management entity, and other network entities, which are not limited in the embodiments of the present application.

[0053] For ease of understanding, some relevant technical knowledge involved in the embodiments of this application is first introduced. The following related technologies can be combined with the technical solutions of the embodiments of this application as optional solutions, and they all fall within the scope of protection of the embodiments of this application. The embodiments of this application include at least part of the following contents.

[0054] As communication technologies develop, communication systems (e.g., 5G) will integrate the market potential of satellite and terrestrial network infrastructure. For example, the 5G standard makes NTN, including satellite segments, part of the recognized 3rd Generation Partnership Project (3GPP) 5G connectivity infrastructure.

[0055] NTN refers to a network or network segment that utilizes radio frequency (RF) resources on satellite or unmanned aerial system (UAS) platforms. Taking satellites as an example, communication satellites are categorized by orbital altitude into low Earth orbit (LEO), medium Earth orbit (MEO), geostationary Earth orbit (GEO), and high elliptical orbit (HEO). LEO is an Earth-centered orbit with an altitude of 2,000 kilometers or less, or with at least 11.25 cycles per day and an eccentricity of less than 0.25. Most man-made objects in outer space are located in LEO. LEO satellites orbit the Earth at high speed (mobility) but in predictable or deterministic orbits.

[0056] Satellites at different orbital altitudes have different orbital periods.

[0057] LEO: Typical altitude is 250-1500 km, with an orbital period of 90-120 minutes.

[0058] MEO: Typical altitude is 5,000-25,000 km, and orbital period is 3-15 hours.

[0059] GEO: Altitude is approximately 35,786 kilometers, and the orbital period is 24 hours.

[0060] As shown in Figures 2 and 3, which used satellites as examples, typical NTN system scenarios for accessing terminal devices involve either NTN transparent payloads or NTN regenerative payloads. The bent-pipe transponder architecture shown in Figure 2 corresponds to the NTN transparent payload, while the regenerative transponder architecture shown in Figure 3 corresponds to the NTN regenerative payload.

[0061] In NTN systems, both satellites and drones are highly mobile. The cells projected by satellites can be fixed relative to the ground or move with the satellite. For example, LEO satellites typically project two types of cells: quasi-fixed cells and quasi-moving cells.

[0062] A cell that is stationary relative to the ground can refer to a service cell with a fixed coverage area. For example, different LEO satellites cover the same area on the ground by adjusting the antenna pointing angle; when a LEO satellite cannot cover the area, another LEO satellite takes over. For satellites in geosynchronous orbit (GSO), the cell projected onto the ground by the satellite can be a fixed cell. For satellites in non-geosynchronous orbit (NGSO), the fixed cell can be served by multiple satellites with alternating coverage.

[0063] For quasi-terrestrial fixed cells, the network (NW) can use the service time (T-service) to indicate when the cell provided by the NTN quasi-terrestrial fixed system will stop providing service for its current coverage area. This service time can be used by the terminal device to start searching for a suitable cell before leaving the current cell to ensure service continuity. For example, the terminal device can perform a cell search after the T-service starts and complete cell handover or cell reselection before the T-service expires.

[0064] In certain quasi-geofixed cell scenarios, the PCI of a serving cell may remain unchanged when the serving satellite corresponding to the serving cell changes. For example, when the serving satellite corresponding to the serving cell switches from satellite 1 to satellite 2, the PCI remains unchanged because the serving ground station remains unchanged. For example, even if the satellite connected to a network device (e.g., a gNB) changes, the network device can still serve the same area, so the PCI within that area remains unchanged.

[0065] In terrestrial networks, communication systems (e.g., NR) cannot assign the same PCI to adjacent cells. If adjacent cells are assigned the same PCI, a terminal device can only synchronize with one of the adjacent cells during the initial cell search process, such as cell handover or cell reselection, in the overlapping area. However, this cell may not be the most suitable cell, and the terminal device may encounter conflicts (interference) during the search process due to the same PCI. Therefore, it is necessary to avoid the same PCI between adjacent cells to improve the handover efficiency of the terminal device.

[0066] However, as mentioned earlier, NTN networks may experience scenarios where the PCI remains unchanged. Therefore, compared to terrestrial cellular networks like NR, NTN systems must support handovers with unchanged PCIs. In other words, in handovers with unchanged PCIs, the NTN system must consider how to resolve conflicts (interference) caused by identical PCIs during the terminal device search process.

[0067] To address this issue, we first analyze handover scenarios in the NTN system. As mentioned earlier, the communication links in the NTN system include service links and feeder links. For different links, PCI-preserving handover primarily involves service link handover and feeder link handover. Service link handover involves handover between the terminal device and the service satellite, while feeder link handover involves handover between the satellite and the gateway.

[0068] Feeder link switching involves both soft and hard feeder link switching. In soft feeder link switching, the NTN payload can connect to more than one NTN gateway within a given period. Communication between the satellite and the different gateways ensures temporary overlap during feeder link switching. In hard feeder link switching, the NTN payload is connected to only one NTN gateway at any given time, so switching between feeder links may result in radio link interruption.

[0069] Serving link handovers also involve soft and hard handover scenarios. From the perspective of the terminal device or serving cell, the distinction between "soft" and "hard" is based on whether the next satellite provides coverage before the previous satellite's coverage disappears. For example, in a hard handover scenario, the terminal device connects to only one satellite at a time. In a soft handover scenario, the terminal device connects to more than one satellite simultaneously.

[0070] For ease of understanding, the following schematically illustrates a satellite handover mode with a constant PCI, using Figure 4. Referring to Figure 4 , satellite 410 moves at speed 404, while satellite 430 moves at speed 403. Both satellites can serve the same area (cell 450). Cell 450 is a fixed cell with a constant PCI. The directions of the two velocities indicate that satellite 410 is the source satellite (old satellite) and satellite 430 is the target satellite (new satellite).

[0071] As shown in Figure 4, as the two satellites move, satellite 430 will connect to gateway 420 after satellite 410. Therefore, a feeder link handoff 401 is required between gateway 420 and the two satellites. If gateway 420 cannot connect to both satellites 410 and 420 simultaneously, feeder link handoff 401 is a hard handoff. If gateway 420 can connect to both satellites 410 and 420 simultaneously, feeder link handoff 401 can be a soft handoff.

[0072] Continuing with Figure 4 , satellite 410 and satellite 430 will sequentially cover cell 450, where the PCI remains unchanged. Therefore, terminal device 440 in cell 450 needs to perform a service link handover 402 from satellite 410 to satellite 430. If terminal device 440 cannot connect to both satellite 410 and satellite 420 simultaneously, service link handover 402 is a hard handover. If terminal device 440 can connect to both satellite 410 and satellite 420 simultaneously, service link handover 402 is a soft handover.

[0073] The above discussion describes soft and hard handovers in conjunction with Figure 4. For the fixed cell in Figure 4, in a hard handover scenario, the aforementioned interference issue may not exist if the PCI remains unchanged, because the terminal device does not receive signals from two satellites simultaneously. However, during overlapping coverage in a soft handover, the terminal device may detect multiple synchronization signals with the same PCI, resulting in conflicts and reduced handover efficiency.

[0074] The following takes the synchronization signal block (SSB) as an example, combined with service link switching, to specifically illustrate the above problem. In the embodiment of the present application, SSB can also represent the synchronization signal / physical broadcast channel block (SS / PBCH block, SSB). That is, the SSB in the embodiment of the present application can be replaced by the SS / PBCH block.

[0075] In a service link handover, when a terminal device's serving satellite switches from a source satellite to a target satellite, the terminal device needs to perform downlink (DL) synchronization with the target satellite to switch to the target satellite. To synchronize with the target satellite, the terminal device needs to detect the SSB associated with the target satellite.

[0076] For example, the terminal device may detect SSB based on an SSB measurement timing configuration (SMTC). SMTC is an SSB-based measurement timing configuration introduced by 5G NR.

[0077] In 5G NR, an SSB pulse consists of multiple SSBs. These multiple SSBs are associated with different SSB indices. Furthermore, SSBs can also be configured for beam management and measurement of different transmission beams, just like the channel state information reference signal (CSI-RS). Among them, the measurement process of SSB or CSI-RS is a power consumption process of the terminal device. In order to reduce the power consumption of the terminal device, SMTC is introduced. SMTC defines the duration and period for the terminal device to measure specific resources. During the SMTC period, the terminal device will perform radio link monitoring / radio resource management measurements on the configured SSB or CSI-RS.

[0078] Exemplarily, when the terminal device receives and applies one or more SMTCs, the SMTC information may include the period and / or offset and / or duration of the measurement window. The terminal device may receive SMTC information from the system information of the serving cell in an idle / inactive state, or receive SMTC from a radio resource control (RRC) release message when transitioning from a connected state to an idle / inactive state. The terminal device may receive and measure SSBs during the SMTC window period to perform processes such as cell reselection.

[0079] Back to the NTN system, in the soft handover scenario, the source satellite and the target satellite provide services to the terminal devices in the service cell at the same time. Therefore, the terminal devices may receive SSBs sent by the source satellite and SSBs sent by the target satellite during the SMTC period.

[0080] Because the PCI of the serving cell remains unchanged, the terminal device cannot distinguish whether the received synchronization signal is from the source satellite or the target satellite, and therefore cannot synchronize with the target satellite via the target satellite's SSB. In other words, synchronization signals with the same PCI sent by the source and target satellites may interfere with the terminal device's synchronization with the target satellite, thereby affecting the terminal device's handover efficiency from the source satellite to the target satellite.

[0081] It should be noted that the problem of low switching efficiency in the NTN system mentioned above, where the synchronization signals detected by the terminal devices interfere with each other due to the same PCI, is only an example. The embodiments of the present application can be applied to any type of scenario where the same PCI affects the communication between the terminal devices and different satellites.

[0082] Based on this, an embodiment of the present application proposes a method for wireless communication. Using this method, a terminal device can detect synchronization signals from a first satellite and a second satellite within a first resource domain and a second resource domain, respectively. This ensures that synchronization signals transmitted by two satellites with the same PCI on the terminal device side do not conflict, thereby improving handover efficiency. For easier understanding, the method proposed in this embodiment of the present application is described in detail below with reference to FIG5 .

[0083] 5 , in step S510 , the terminal device receives a first switching command.

[0084] The terminal device is any of the terminal devices described above. In some embodiments, the terminal device is a user equipment in a quasi-terrestrial fixed cell of an NTN system. In some embodiments, the terminal device is a communication device that supports NTN features in both GSO and NGSO scenarios. For example, the terminal device supports mobility in both GSO and NGSO scenarios.

[0085] The first handover command is used to instruct the terminal device to perform a handover from the first satellite to the second satellite. The first handover command may also be referred to as a first handover instruction. For example, the first handover command may instruct the terminal device to synchronize with the second satellite.

[0086] In some embodiments, synchronization of the terminal device with the second satellite may include one or more of downlink synchronization, uplink (UL) synchronization, and service link synchronization. As an example, the first handover command may instruct the terminal device to perform downlink synchronization with the second satellite.

[0087] The first satellite and the second satellite are two serving satellites that are sequentially connected to the terminal device. In other words, the first satellite and the second satellite are two serving satellites that sequentially cover and provide service to the serving cell where the terminal device is located. The serving satellite can be any satellite that provides communication services to the terminal device or the serving cell where the terminal device is located. In some embodiments, the terminal device and the serving satellite can communicate via a service link.

[0088] The first satellite is a serving satellite currently providing services, and thus may also be referred to as a source satellite or source NTN. The second satellite is a serving satellite that provides services after the first satellite, and thus may also be referred to as a target satellite or target NTN.

[0089] The first satellite and the second satellite may be any of the two satellites described above. In some embodiments, the first satellite and the second satellite may be satellites that move based on similar satellite orbits or at the same orbital altitude. For example, the first satellite and the second satellite may both be LEO satellites. In some embodiments, the first satellite and the second satellite may be satellites that move based on different satellite orbits or at different orbital altitudes.

[0090] In some embodiments, the second satellite may be one or more target satellites that will provide services to the terminal device. For example, the second satellite may be one or two target satellites.

[0091] As an example, a terminal device may perform a handoff from a first satellite to a target satellite.

[0092] As an example, a terminal device can perform a handover from a first satellite to multiple target satellites to improve handover efficiency. For example, the terminal device can select the target satellite with the strongest signal from multiple synchronization signals of the multiple target satellites as the next serving satellite, thereby ensuring communication quality after the handover.

[0093] Switching from a first satellite to a second satellite can also be called a satellite switch or a serving satellite switch. This switch can be a service link switch or a feeder link switch. For example, when the serving satellite of a terminal device switches from the first satellite to the second satellite, the service link connecting the terminal device to the first satellite switches to a service link connecting to the second satellite. For example, when the first and second satellites are connected to the same terrestrial gateway, when the serving satellite switches from the first satellite to the second satellite, the feeder link connecting the gateway to the first satellite switches to a feeder link connecting to the second satellite.

[0094] It should be understood that regardless of whether the ground gateways connected to the first satellite and the second satellite are the same, the embodiments of the present application can be applied as long as the service satellite of the terminal device is switched from the first satellite to the second satellite.

[0095] In some embodiments, the handoff from the first satellite to the second satellite can be a soft handoff. During this handoff, the first and second satellites simultaneously provide services to the terminal device to avoid link interruption. That is, the terminal device can perform the handoff during a period of overlapping coverage between the two satellites. During this overlapping coverage period, the terminal device can receive the first synchronization signal from the second satellite and establish a connection with the second satellite. For example, the terminal device can perform downlink synchronization with the second satellite before the T-service of the first satellite begins or before the T-service expires.

[0096] In some embodiments, the handoff from the first satellite to the second satellite can be a hard handoff. During this handoff, the terminal device begins establishing a connection with the second satellite only when the first satellite is out of service. For example, the terminal device can perform downlink synchronization with the second satellite when the T-service of the first satellite expires.

[0097] As an example, since a hard handoff from a first satellite to a second satellite does not pose interference issues, the second satellite does not need to consider the timing of the first satellite's synchronization signal transmission when transmitting the synchronization signal. For example, the second satellite does not need to be limited to transmitting SSBs at a different time than the first satellite's SSB transmission timing. Furthermore, the second satellite may not be configured with a time offset / SMTC. In this scenario, the terminal device can autonomously estimate the time window for the SSB provided by the second satellite based on information such as the ephemeris and common TA of the first and second satellites.

[0098] In some embodiments, the handover of the terminal device from the first satellite to the second satellite may be a random access channel (RACH) handover or a RACH-free handover, which is not limited herein.

[0099] In some embodiments, when the terminal device performs a handover from a first satellite to a second satellite, the PCI of the serving cell where the terminal device is located remains unchanged.

[0100] For example, when the first and second satellites are connected to the same network device, the PCI of the serving cell remains unchanged because the network device providing the service remains unchanged. For example, in Figure 4 , satellite 410 is the first satellite, satellite 430 is the second satellite, and the first and second satellites are sequentially connected to gateway 420. The PCI of the cells covered by the two satellites remains unchanged.

[0101] Exemplarily, when the first satellite and the second satellite are connected to different network devices, the PCI of the serving cell where the terminal device is located may also remain unchanged.

[0102] In some embodiments, when performing soft handover, the network device may configure an information field to indicate whether it supports PCI-invariant handover. The indication information may be broadcast information or proprietary information. The broadcast information may be carried in a system information block (SIB).

[0103] The first switching command received by the terminal device comes from the network device. For example, if the current serving satellite of the terminal device can no longer provide service, the network device can send the first switching command to the terminal device and the serving cell where the terminal device is located in advance through broadcasting.

[0104] The network device may be a communications device that provides services to the serving cell via the first satellite. For example, the network device may be a ground-based network device connected to the first satellite. In another example, the network device may be a network device carried by the first satellite itself. In this scenario, the first satellite may also be referred to as the network device.

[0105] In some embodiments, a network device may send a first handover command to a terminal device via a first satellite. In one embodiment, when the first satellite and the second satellite are connected to the same network device, the network device sends the first handover command to the terminal device. In another embodiment, when the first satellite and the second satellite are connected to different network devices, the network device connected to the first satellite is the source network device, and the network device connected to the second satellite is the target network device. Before the handover process, the terminal device has not yet established synchronization with the second satellite, and the network device sending the first handover command is the source network device.

[0106] It should be noted that the network device connected to the first satellite and the second satellite may be any one or more network devices described above, and is not limited here.

[0107] In some embodiments, network equipment can assist a terminal device in avoiding or mitigating interference during a handover. Specifically, interference between a first satellite and a second satellite can potentially be avoided or mitigated by the gNB. This will be explained in detail later in conjunction with assistance information related to the second satellite.

[0108] As an example, when a first satellite and a second satellite are connected to the same network device, the network device can coordinate the resources used to transmit synchronization signals between the two satellites to resolve potential conflicts. For example, the network device can configure the first and second satellites to not transmit the same SSB or have the same SSB index when connected to a terminal device to avoid conflicts. As an implementation, the second satellite can be configured with an SSB index different from that of the first satellite and transmit the second satellite's SSB index information via a broadcast message from the first satellite.

[0109] As an example, the network device may send auxiliary information for handover to the terminal device to ensure that synchronization signals with the same PCI on the terminal device side do not conflict. For example, the network device may send relevant information for handover to the terminal device when the first satellite senses or detects the second satellite.

[0110] As an example, to avoid a possible collision between the two satellites, the network device may configure the first satellite and the second satellite to transmit SSBs on different resources. For example, the network device may configure different time windows for the SSBs transmitted by the second satellite and the SSBs transmitted by the first satellite.

[0111] The network device may send the first handover command to the terminal device in a variety of ways. For example, the first handover command may be included in system information. For example, the first handover command may be included in dedicated signaling.

[0112] The first handover command may include handover indication information and may also include various other handover information. For example, the first handover command may include second information. The second information may indicate that the network device supports handover without changing the PCI of the serving cell. For example, the first handover command may also include relevant time information for the terminal device to perform handover, so that the terminal device can synchronize with the second satellite in a timely manner, thereby improving handover efficiency.

[0113] In some embodiments, the first handover command may include a first time point at which the first satellite stops serving and a second time point at which the terminal device begins synchronizing with the second satellite. When the second time point is earlier than the first time point, the handover is a soft handover; when the second time point is not earlier than the first time point, the handover is a hard handover. For example, if the second time point is earlier than the first time point, the terminal device may perform a handover from the first satellite to the second satellite within the time period from the second time point to the first time point. This handover is a soft handover within the overlapping coverage period between the first and second satellites.

[0114] As an example, the first time point may be the T-service mentioned above. As mentioned above, when the T-service expires, the first satellite will stop providing services to the terminal device or the serving cell where the terminal device is located.

[0115] As an example, the second time point is the earliest time at which the terminal device can begin synchronization with the second satellite. This earliest time point can be referred to as the time at which the terminal device begins synchronization with the second satellite. The second time point can be denoted as T-start. That is, at T-start, the second satellite begins providing service to the serving cell.

[0116] As an implementation method, in a satellite soft handover scenario, a terminal device can start synchronizing with a second satellite before the T-service of the first satellite. In other words, the T-start of the second satellite is earlier than the T-service of the first satellite. Between T-start and T-service, the terminal device can independently determine the time to start synchronization.

[0117] In some embodiments, T-start may be carried in SIB information so that the terminal device can obtain it in a timely manner.

[0118] In step S520, the terminal device detects the first synchronization signal and the second synchronization signal in the first resource domain and the second resource domain respectively according to the first information.

[0119] In some embodiments, the first information directly indicates the first resource domain and the second resource domain. The terminal device can detect the first synchronization signal in the first resource domain and detect the second synchronization signal in the second resource domain.

[0120] In some embodiments, the terminal device may determine the first resource domain and the second resource domain based on the first information. Further, the terminal device may detect the first synchronization signal in the first resource domain and detect the second synchronization signal in the second resource domain.

[0121] The first synchronization signal is associated with the first satellite, meaning that the first synchronization signal is a synchronization signal transmitted by the first satellite. That is, the first synchronization signal includes all synchronization signals transmitted by the first satellite. In some embodiments, the first synchronization signal may be a synchronization signal transmitted by a network device via the first satellite to a terminal device or a serving cell where the terminal device is located. For example, the network device may transmit or broadcast the first synchronization signal to terminal devices within the serving cell via the first satellite. In some embodiments, the first synchronization signal may be a synchronization signal broadcast by the first satellite itself.

[0122] The second synchronization signal is used for synchronizing the terminal device with the second satellite, and may alternatively be related to the second satellite. Exemplarily, the second synchronization signal may include all signals sent by the second satellite for synchronization.

[0123] In some embodiments, the second synchronization signal may be a synchronization signal transmitted by the network device to the terminal device or the serving cell where the terminal device is located via the second satellite. In some embodiments, the second synchronization signal may be a synchronization signal broadcast by the second satellite itself. For example, when the second satellite carries a base station, the second satellite may directly broadcast the second synchronization signal.

[0124] The first synchronization signal and the second synchronization signal may be any synchronization-related signal transmitted by the first satellite and the second satellite. In some embodiments, the first synchronization signal and the second synchronization signal may be synchronization signal blocks or synchronization signal / physical broadcast channel signal blocks. For example, the first synchronization signal is a first SSB and the second synchronization signal is a second SSB. In some embodiments, the first synchronization signal may be a primary synchronization signal (PSS) and / or a secondary synchronization signal (SSS). For example, the first synchronization signal is a first PSS and / or a first SSS, and the second synchronization signal is a second PSS and / or a second SSS.

[0125] In some embodiments, the first synchronization signal and the second synchronization signal may be the same type of synchronization signal. For example, the first synchronization signal and the second synchronization signal may both be SSB.

[0126] In some embodiments, the first synchronization signal and the second synchronization signal may be different types of synchronization signals. For example, the first synchronization signal is a first SSB, and the second synchronization signal is a second PSS and a second SSS, or vice versa.

[0127] In some embodiments, the first synchronization signal and the second synchronization signal may be SSBs designed in a conventional structure. The first synchronization signal and the second synchronization signal may include information for synchronization. In some embodiments, the first synchronization signal and the second synchronization signal may be SSBs designed in an improved structure.

[0128] Since the first satellite is currently providing services to the terminal device, the first synchronization signal can be used for various services, such as beam management and connection recovery between the terminal device and the first satellite, without limitation. The second synchronization signal requires the terminal device to synchronize with the second satellite via the second synchronization signal to establish a connection. Therefore, the second synchronization signal can be used for limited services, such as initial beam pairing between the terminal device and the second satellite.

[0129] After detecting the second synchronization signal, the terminal device can synchronize with the second satellite using the second synchronization signal. This synchronization can be used to connect the terminal device to the network of the second satellite to complete the handover. For example, if the PCI remains unchanged, after the terminal device achieves downlink synchronization with the second satellite using the second synchronization signal, RACH handover or RACH-free handover can be immediately triggered.

[0130] To prevent or mitigate interference of the first synchronization signal with synchronization between the terminal device and the second satellite, the terminal device may determine, based on the first information, a first resource domain and a second resource domain associated with the first synchronization signal and the second synchronization signal, respectively. For simplicity, the following explanation is based on the second resource domain associated with the second synchronization signal as an example.

[0131] The second resource domain is associated with the second synchronization signal, which may indicate that some or all resources in the second resource domain are used to carry the second synchronization signal. In some embodiments, the network device configures the second satellite to transmit the second synchronization signal to the terminal device via resources in the second resource domain. In some embodiments, the second satellite may transmit the second synchronization signal to the terminal device directly via resources in the second resource domain.

[0132] In some embodiments, the second resource domain is related to the second synchronization signal, which may also mean that the terminal device performs reception and measurement of the second synchronization signal on part or all of the resources in the second resource domain.

[0133] It should be noted that the second resource region being associated with the second synchronization signal does not necessarily mean that the second synchronization signal must be transmitted on resources in the second resource region. For example, although the resources in the second resource region are configured to carry the second synchronization signal, the second satellite may not transmit the second synchronization signal on the second resource region due to various reasons.

[0134] Optionally, the second resource domain may represent a resource area, so that the terminal device can detect the second synchronization signal in the resource area. The second resource domain may also be replaced by a second resource range.

[0135] As an embodiment, the second resource region may be an SMTC window. The terminal device may perform measurement of the second synchronization signal based on the carrier (frequency) used by the service cell broadcast by the second satellite based on the SMTC.

[0136] In some embodiments, the resources in the second resource domain may include any resources used to carry the second synchronization signal. Exemplarily, the resources in the second resource domain may include time domain resources, frequency domain resources, orthogonal code sequence resources, or a combination thereof.

[0137] In some embodiments, the resources in the second resource domain may be time domain resources used to carry the second synchronization signal. For example, the second resource domain may be a time window. The terminal device may determine the time domain range corresponding to the second resource domain based on the configuration information of the time window and detect the second synchronization signal.

[0138] In some embodiments, the resources in the second resource domain may be frequency domain resources used to carry the second synchronization signal. For example, the second resource domain may include frequency domain resources within a certain specific carrier range.

[0139] The resources in the second resource domain may be continuous or discontinuous, which is not limited here.

[0140] In some embodiments, the second resource field may be resources configured by the network device for the second satellite. As an example, when the second resource field is a time window, the network device may configure the time window of the second satellite to the terminal device in the form of an SMTC offset. The SMTC configuration information may be used to indicate the carrier used by the second satellite, the subcarrier spacing (SCS) used by the carrier, and the duration of multiple SSB-based measurements.

[0141] The first resource domain may be any resource region orthogonal to the second resource domain to avoid mutual interference between the first synchronization signal and the second synchronization signal.

[0142] In some embodiments, the first resource domain and the second resource domain include resources of the same type to facilitate determining whether they are orthogonal. For example, the resources in the first resource domain and the second resource domain are both time-frequency resources.

[0143] The terminal device may determine the first resource domain and the second resource domain based on the first information. In other words, the first information may be used by the terminal device to determine the first resource domain and the second resource domain. Exemplarily, the first information may explicitly or implicitly indicate the first resource domain and / or the second resource domain.

[0144] In some embodiments, since the resources in the first resource domain and the second resource domain are orthogonal, when the first information indicates the first resource domain or the second resource domain, the terminal device can determine the second resource domain or the first resource domain according to the indicated first resource domain or the indicated second resource domain.

[0145] As an example, the first information may indicate a first resource domain, and the second resource domain may include resources other than the first resource domain. The terminal device will not detect the first synchronization signal on the second resource domain, and no interference will be generated. For example, the terminal device may know the time when the first synchronization signal appears through communication with the first satellite, and the synchronization signal detected outside of these times may be considered to be broadcast by the second satellite. For another example, the terminal device may know the time when the first synchronization signal appears based on the public timing advance (TA), ephemeris table, or ephemeris parameters of the first satellite, thereby determining the possible time when the second synchronization signal appears.

[0146] In some embodiments, the first information may directly indicate all resources included in the second resource domain to avoid the terminal device from blindly searching for the second synchronization signal. For example, the first information may directly indicate the index of the second synchronization signal, and the terminal device may detect the second synchronization signal at the corresponding position according to the index.

[0147] In some embodiments, the first information may indicate a first resource region and a second resource region, so that the terminal device can more clearly distinguish whether the received synchronization signal is from the first satellite, the second satellite, or other satellites.

[0148] As an example, when the first resource domain and the second resource domain are time-frequency resources, the first resource domain may include a first time window, and the second resource domain may include a second time window. The first information may include SMTC and auxiliary information. The terminal device may determine the first time window and the second time window based on the SMTC and auxiliary information in the first information. For example, in order to enable a terminal device in an idle / inactive state / connected state to correctly measure SSB in an NTN scenario, the terminal device may adjust the measurement time window of SMTC based on the ephemeris parameters and offset parameters of different satellites. That is, for different propagation times and offset parameters from different satellites, the terminal device may use different offsets to obtain the first time window and the second time window. Furthermore, the terminal device may detect the first synchronization signal sent by the first satellite and the second synchronization signal sent by the second satellite in the first time window and the second time window, respectively.

[0149] As an example, the first information may indicate a first time window associated with the first synchronization signal and a second time window associated with the second synchronization signal. Exemplarily, both the first time window and the second time window may be determined based on the SMTC. That is, the terminal device may set two SMTC time windows based on one or more SMTCs. The first SMTC time window (SMTC1) is applicable to SSB measurements of a first satellite in a serving cell, and the second SMTC time window (SMTC2) is applicable to SSB measurements of a second satellite with the same PCI.

[0150] As an implementation, when handover-related assistance information is transmitted to a terminal device via a broadcast message or a dedicated message, the terminal device can also determine the SMTC offset and measurement gap configuration update for the second satellite accordingly. Based on the SMTC-related information, the terminal device can set two SMTC time windows corresponding to the two satellites.

[0151] As an implementation, the terminal device may further set the first SMTC time window and the second SMTC time window based on auxiliary information associated with the second satellite. For example, when the auxiliary information includes a time offset of the second SSB relative to the first SSB, the terminal device may set the first SMTC time window and the second SMTC time window based on the time offset.

[0152] In some embodiments, the first resource domain and the second resource domain have an associated relationship, such as an offset. The second resource domain can be determined based on the first resource domain and the associated relationship. For example, for a first satellite and a second satellite covering a serving cell with the same PCI, a difference in propagation delay or offset parameter between the two satellites and a terminal device may cause an offset in the synchronization signal measurement window.

[0153] In some embodiments, the second resource domain may be determined based on the first resource domain and the first offset. When the first resource domain is a time domain resource or a time-frequency resource, the first offset may be a time offset. When the first resource domain is a frequency domain resource or a time-frequency resource, the first offset may be a frequency offset.

[0154] As an example, the first information can be used to determine a relative offset between a first time window and a second time window. After the terminal device determines the first time window, the second time window can be determined based on the first time window and the first offset. For example, the first time window can be determined based on the SMTC, and the second time window can be determined based on the first time window and the first offset.

[0155] As an implementation, the terminal device can configure the time window for broadcasting the SSB from the second satellite using the SMTC window (first time window) and the time offset (first offset) of the SSB from the second satellite relative to the SSB from the first satellite. The first offset will be exemplified below using the time offset as an example with reference to Figures 7 and 8.

[0156] In some embodiments, the terminal device may adjust the first resource domain and / or the second resource domain based on the detection of the synchronization signal. For example, when the terminal device fails to detect the second synchronization signal within the second time window, the terminal device may adjust the second time window based on the auxiliary information associated with the second satellite and / or the auxiliary information associated with the handover. Furthermore, the terminal device may send adjustment information for the second time window to the network device.

[0157] As an example, when the second time window is an SMTC window, if the SSBs of the second satellite associated with the SMTC are all detectable, the terminal device can continue measuring according to the SMTC. If the SSBs of the second satellite are not detected within the SMTC window, the terminal device can adjust the SMTC window and the period, offset, and / or duration of the measurement gap corresponding to the window based on various information. For example, the terminal device can adjust the second time window based on the propagation delay of the current first satellite of the serving cell and the propagation delay of the second satellite whose SSB cannot be detected.

[0158] In some embodiments, the terminal device may adjust the first resource domain and / or the second resource domain according to the movement of the satellite and itself. For example, the terminal device may adjust the SMTC used to determine the first time window and the second time window according to the movement information of the two satellites.

[0159] As an example, the terminal device may dynamically or periodically adjust the first time window and / or the second time window. For example, when the time window is an SMTC window or is determined based on the SMTC window, the terminal device may dynamically or periodically update the SMTC and measurement gap configuration based on its own location information and / or satellite movement information.

[0160] In some embodiments, after the terminal device adjusts the time window or SMTC, the time window adjustment information may be reported to the network device corresponding to the first satellite and / or the second satellite. That is, the terminal device may notify the network device of these updates by sending a report. For example, the report reported by the terminal device may indicate the time offset of the SMTC relative to the measurement SSB of the first satellite. For example, the report may indicate the time offset of the SMTC measurement window relative to the starting position of the SSB of the second satellite. For example, the report may indicate the time offset of the starting position of the measurement gap within the serving cell measurement gap configuration period.

[0161] In some embodiments, when the first resource domain and the second resource domain are frequency domain resources, the first information may indicate the frequency ranges corresponding to the first resource domain and the second resource domain, respectively. For example, the first synchronization signal and the second synchronization signal may be sent on different carriers to avoid mutual interference.

[0162] As an example, different carriers may include carriers with different subcarrier spacings. The size of the subcarrier spacing corresponding to the synchronization signal can be selected by the system based on actual conditions. Generally speaking, the smaller the subcarrier spacing, the faster the signal transmission speed, but it also increases signal interference and noise. Conversely, if the subcarrier spacing is too large, the signal transmission speed will be slower, but the signal quality and reliability will be higher. In actual applications, the subcarrier spacing is usually selected based on different application scenarios and requirements. For example, in high-speed mobile scenarios, a smaller subcarrier spacing is required to improve signal transmission speed and reliability. In low-speed mobile or stationary scenarios, a larger subcarrier spacing can be selected to reduce signal interference and noise.

[0163] As an example, the first information may indicate a first carrier and a second carrier having different subcarrier spacings. The first carrier is associated with a first synchronization signal, and the second carrier is associated with a second synchronization signal. That is, to avoid synchronization signal conflicts, the first synchronization signal and the second synchronization signal may be sent on carriers corresponding to different subcarrier spacings.

[0164] In some embodiments, the first information may include a parameter indicating a signal index (e.g., an SSB index) corresponding to the synchronization signal. In this scenario, the first resource domain and the second resource domain may be parameters representing different signal indexes, or may be time-frequency resources where different synchronization signals are located. After the terminal device determines the second signal index corresponding to the second synchronization signal based on the first information, it may detect the synchronization signal within the resource corresponding to the second signal index.

[0165] As an example, during satellite soft handover, the network device may provide the terminal device with first signal index information and second signal index information corresponding to the first synchronization signal and the second synchronization signal, respectively, using parameters. The first signal index is different from the second signal index. The terminal device may select different signal indexes for different satellites for measurement.

[0166] As an example, two satellites can use different beams to transmit synchronization signals during overlapping coverage. Different beams correspond to different SSB indices. The terminal device only needs to detect the SSB index of the second satellite.

[0167] As an example, the first information may include a first parameter for indicating a synchronization signal position or a synchronization signal index. The terminal device may bitwise invert the bits of the first parameter to obtain a second parameter. The first signal index and the second signal index may be determined by the first parameter and the second parameter, respectively. For example, the terminal device may determine the first signal index based on the first parameter to determine the resource where the first synchronization signal is located. The second parameter is used to determine the second signal index. For another example, the terminal device may also determine the first signal index based on the second parameter to determine the resource where the first synchronization signal is located. The first parameter is used to determine the second signal index.

[0168] As a possible implementation method, the first parameter may be inOneGroup. The parameter inOneGroup includes 8 bits. By configuring the value range of 8 bits of inOneGroup, the terminal device can detect the second synchronization signal based on the second signal index and will not detect the first synchronization signal. For example, when inOneGroup = 10101010, the terminal device will detect the SSBs at the 1st, 3rd, 5th and 7th positions (that is, SSB0, SSB2, SSB4, SSB6), but will not detect the SSBs at the 2nd, 4th, 6th and 7th positions (that is, SSB1, SSB3, SSB5, SSB7).

[0169] As an example, the first information may include the first parameter and the second parameter described above to indicate the resources corresponding to the first synchronization signal and the second synchronization signal, respectively. As an implementation method, the second parameter may be inOneGroup(1). When configuring the value range of 8 bits of inOneGroup, the value range of 8 bits of inOneGroup(1) can also be obtained. The values ​​of the two parameters inOneGroup and inOneGroup(1) are related. As an implementation method, the terminal device can determine the first signal index and detect the first synchronization signal based on the value of inOneGroup, and can also determine the second signal index and detect the second synchronization signal based on the value of inOneGroup(1).

[0170] As a possible implementation, the value of inOneGroup(1) is obtained by inverting the 8 bits of inOneGroup, so the signal indexes indicated by inOneGroup and inOneGroup(1) will not overlap or conflict.

[0171] For example, if inOneGroup=[10101010], the terminal device detects SSB0, SSB2, SSB4, and SSB6 in the NTN network of the first satellite; if inOneGroup(1)=[01010101], the terminal device detects SSB1, SSB3, SSB5, and SSB7 in the NTN network of the second satellite.

[0172] In some embodiments, the first information may include a combination of multiple types of information. For example, when the signal index is combined with the SMTC measurement time window, the first information may indicate the first parameter and the second parameter, and may also indicate one or more time slots offset between the first and second time windows. For another example, when carrier information is combined with SMTC, the first SMTC for measuring the first synchronization signal may be located on the first carrier, while the second SMTC for measuring the second synchronization signal may be located on the second carrier.

[0173] The above describes a method for determining a first resource domain and a second resource domain using multiple types of first information. After determining the first resource domain and the second resource domain, the terminal device detects the corresponding synchronization signal in each resource domain. For ease of understanding, the following example uses the SSB synchronization signal as an example, and illustrates the time domain position of the SSB and the process of the terminal device detecting the synchronization signal in conjunction with Figure 6.

[0174] During the SSB search process, the terminal device first receives signals from all possible frequencies within the corresponding frequency band. Specifically, after low-pass filtering at the baseband, the SSB bandwidth signal is retained. Then, a correlation peak search is performed using the PSS and SSS to determine frame boundaries and the cell PCI. It should be noted that when performing a sliding correlation between the PSS and SSS, multiple peaks may be present. In this case, the strongest correlation peak is selected, thereby selecting the strongest SSB.

[0175] The terminal device can determine the time domain and frequency domain parameters of the SSB through the broadcast SIB information. Specifically, the terminal device can obtain the period of the SSB in the time domain and the position in the frequency domain through SIB1. Among them, the time domain parameters can be obtained through SIB→ServingCellConfigCommonSIB→ssb→periodicityServingCellSIB. The time domain position can be determined according to the time domain position determination method of the SSB pattern given by the 3rd Generation Partnership Project (3GPP) protocol.

[0176] Furthermore, when the terminal device receives the first SSB and obtains the master information block (MIB) from the physical broadcast channel (PBCH), it determines the location of SIB1. After receiving SIB1, the terminal device can determine the frequency domain location of subsequent SSB periods, eliminating the need for blind detection across the entire frequency band.

[0177] Furthermore, while determining the frequency domain position, the terminal device also determines the period of the SSB in the time domain. From the time domain perspective, there will be multiple candidate SSBs. The network device can describe the position information of the SSB in SIB1 through the SIB1→ServingCellConfigCommonSIB→ssb→PositionsInBurst parameter. Specifically, the parameter inOneGroup in ssb-PositionInBurst can indicate the location where the SSB is sent, and inOneGroup is generally represented by 8 bits. For different frequency bands or frequency ranges, inOneGroup can indicate the position information of the SSB in different ways.

[0178] For example, when f ≤ 3 GHz, the maximum number of SSBs in a synchronization signal (SS) burst set is 4, so 4 bits are sufficient. In other words, 4 bits are temporarily ignored. As an example, the leftmost 4 bits in inOneGroup are valid, meaning the upper 4 bits are valid and the lower 4 bits are invalid. The upper 4 bits in inOneGroup can represent SSB0 to SSB3 from left to right.

[0179] For example, when 3 GHz < f ≤ 6 GHz, the maximum number of SSBs in an SS burst set is 8, requiring 8 bits to represent. That is, all 8 bits of inOneGroup are valid. The 8 bits represent SSB0 to SSB7 from left to right.

[0180] For example, when f>6 GHz, the maximum number of SSBs in an SS burst set is 64. Not only are all 8 bits of inOneGroup valid, but an additional field of 8 bits of the parameter groupPresence is also required to indicate the position of the SSB.

[0181] Figure 6 is used as an example to illustrate the time domain location of SSB. In Figure 6, a radio frame is 10 ms, or 5 ms for a half-frame. The subcarrier spacing is 15 kHz, so there are five time slots in a half-frame, from time slot 0 to time slot 4. Each time slot has 14 symbols, and the multiple time slot symbols within the five time slots are uniformly numbered. For example, the symbols in time slot 0 are symbol 0 to symbol 13, the symbols in time slot 1 are symbol 14 to symbol 27, and so on.

[0182] In the frequency band f ≤ 3 GHz, there are two SSBs in one time slot. Each SSB occupies four symbols. As shown in Figure 6, the first two time slots of a half-frame contain SSBs, resulting in a total of four SSBs. In Figure 6, the starting symbols of the four SSBs are symbols 2, 8, 16, and 22, respectively. Based on these four starting symbols, the terminal device can determine the positions of the four SSBs within the time domain.

[0183] The above, combined with Figures 5 and 6, describes how to determine the first and second resource domains and how to detect synchronization signals in the resource domains. Using this method, a network device can configure the first and second satellites to transmit the first and second synchronization signals in the first and second resource domains, respectively. A terminal device can also detect synchronization signals in the two resource domains, thereby avoiding or mitigating mutual interference between synchronization signals.

[0184] To facilitate determining the first resource domain and the second resource domain, the first information may include relevant information about the first and second satellites, or the first information may be determined based on this relevant information. Because the terminal device is currently connected to the network where the first satellite resides, the terminal device can determine the relevant information about the first satellite. Therefore, how the terminal device determines the relevant information about the second satellite is a problem that needs to be solved.

[0185] In some embodiments, the terminal device may receive assistance information related to the second satellite. For example, the assistance information may be provided to the terminal device by the first satellite or by the second satellite.

[0186] The auxiliary information related to the second satellite may include information for handover. As an example, the auxiliary information related to the second satellite may be the NTN configuration information of the second satellite. For example, the auxiliary information may include ephemeris and public TA parameters. During handover, the public TA and ephemeris of the second satellite are important information for the terminal device to perform full time and frequency domain synchronization compensation. Therefore, before the handover begins, it is necessary to provide the public TA and ephemeris of the second satellite. For another example, the auxiliary information may also include the new public TA, K mac and parameters such as a specific SMTC offset. For another example, when the second synchronization signal is SSB, the auxiliary information may also include information related to the second synchronization signal, such as SSB index information and SSB offset.

[0187] In some embodiments, the assistance information related to the second satellite further includes configuration parameters of the second SMTC corresponding to the second synchronization signal, such as a time offset of the second SMTC relative to the SMTC of the first satellite.

[0188] In some embodiments, the assistance information associated with the second satellite may further include partial or complete parameter information of the second synchronization signal to facilitate detection of the second synchronization signal by the terminal device. For example, the parameter information may include second signal index information, synchronization information of the second synchronization signal, and a time offset of the second synchronization signal relative to the first synchronization signal.

[0189] As an example, when the first synchronization signal is the first SSB and the second synchronization signal is the second SSB, the auxiliary information related to the second satellite may include one or more of the following: index information of the second SSB, the second signal index, the difference between the second SSB index and the first SSB index, the time offset of the second SSB, the offset of the second SSB relative to the first SSB, and the synchronization information of the second SSB.

[0190] As an example, the assistance information related to the second satellite may also be the ephemeris information of the second satellite. For example, the assistance information may include the second satellite orbit ephemeris parameters and the position, velocity, and time information of the second satellite (i.e., PVT information).

[0191] In some embodiments, assistance information related to the second satellite can be sent to the terminal device in various ways. For example, because the first and second satellites overlap in coverage of the serving cell, the assistance information related to the second satellite can be included in system information. The terminal device can read the relevant information about the second satellite via broadcast information. For example, the assistance information related to the second satellite can also be sent to the terminal device via dedicated signaling.

[0192] In some embodiments, a terminal device may receive assistance information related to a second satellite transmitted by a first satellite. In other words, the first satellite may transmit assistance information related to the second satellite to the terminal device. On the network side, the network device transmits the assistance information related to the second satellite to the terminal device via the first satellite.

[0193] It should be noted that the network device sending auxiliary information related to the second satellite to the terminal device through the first satellite may refer to the first satellite of the network device directly sending the auxiliary information related to the second satellite to the terminal device, or it may refer to the network device sending the auxiliary information related to the second satellite to the first satellite, and the second satellite forwarding the auxiliary information related to the second satellite to the terminal device.

[0194] In some embodiments, the terminal device may also receive assistance information related to the second satellite sent by the second satellite.

[0195] In some embodiments, the assistance information related to the second satellite may be carried in a SIB. Alternatively, the first satellite may broadcast SIB19 to transmit the assistance information related to the second satellite.

[0196] As an example, the assistance information related to the second satellite may be carried in SIB19 of the second satellite or the first satellite. When the terminal device is in the serving cell, the terminal device may read SIB19 to determine the assistance information.

[0197] As an example, a terminal device may obtain assistance information related to the second satellite from the SIB19 of the first satellite at a time point after or before the second satellite's appearance time. The second satellite appearance time refers to the time when the first satellite senses or perceives the second satellite. It may also be the time associated with the second satellite determined by the first satellite through network equipment or other means such as ephemeris information. After the second satellite appears, the satellite assistance information of the serving cell in the SIB19 can be used by the terminal device to synchronize with the second satellite.

[0198] For example, according to the existing SIB19 abstract syntax notation one (ASN.1) structure, SIB19 contains two parts of information: one for the serving cell and the other for the neighboring cell. Since the PCI remains unchanged before and after the serving link handover, the assistance information associated with the second satellite can be information about the serving cell.

[0199] For example, SIB19 can introduce a new field to provide assistance information for the second satellite during a serving link handover while maintaining the same PCI. After reading SIB19, the terminal device can distinguish the SSBs or SSB indices of the first and second satellites during the overlap duration to avoid conflicts.

[0200] As an example, the terminal device may obtain SIB19 information from the second satellite. In this scenario, after the second satellite appears, the terminal device still needs a certain amount of time to obtain SIB19.

[0201] In some embodiments, the terminal device may obtain assistance information related to the second satellite through an RRC dedicated message.

[0202] In some embodiments, the terminal device may acquire assistance information related to the second satellite before the T-Service begins. That is, the terminal device begins synchronizing with the target satellite before the T-Service of the first satellite to perform soft handover.

[0203] It should be understood that the terminal device can be any terminal in the serving cell. When the PCI remains unchanged, all terminal devices in the serving cell will perform synchronization with the second satellite under serving link soft handover. When the network device broadcasts the auxiliary information related to the second satellite in the SIB19 of the serving cell may depend on the network (NW) implementation. For example, when the NW starts broadcasting this information, the NW may notify the terminal device to re-acquire SIB19 through the current process (e.g., the system information modification process). Furthermore, the terminal device can estimate the TA based on the auxiliary information related to the second satellite and perform TA pre-compensation before the random access process.

[0204] In some embodiments, the network may periodically provide the terminal device with assistance information related to the second satellite. For example, the first satellite may periodically send assistance information related to the second satellite via a broadcast message.

[0205] In some embodiments, the network also needs to provide the terminal device with necessary assistance information to perform a hard handoff or soft handoff process based on a satellite with unchanged PCI. During a soft handoff, the coverage areas of the first satellite and the second satellite will overlap for a period of time. Before T-Service, the first satellite of the serving cell can provide the terminal device with assistance information about the second satellite (which will become the new serving cell).

[0206] As mentioned above, there is a certain offset between the first resource domain and the second resource domain. Therefore, when the terminal device determines the first resource domain, the second resource domain can be determined by the first resource domain and the first offset. To more accurately determine the second resource domain, the first offset needs to comprehensively consider relevant information about the first and second satellites. This information may include, for example, satellite location information or movement information.

[0207] Exemplarily, when the resource domain is a measurement window of SMTC, the first offset is also the offset of the SMTC measurement window.

[0208] In some embodiments, the first offset can be determined based on one or more of the following information: the propagation delay of the terminal device in communicating with the first satellite and the second satellite, respectively; the offset parameters corresponding to the first satellite and the second satellite, respectively; the position information of the first satellite and the second satellite; the position information of the terminal device; and the movement information of the second satellite.

[0209] As an example, the location information of a terminal device can be determined in a variety of ways. For example, for a terminal device that supports the global navigation satellite system (GNSS), the location information of the terminal device can be obtained through GNSS. For another example, for a terminal device that does not support GNSS, the location information of the terminal device can be obtained through network-assisted positioning.

[0210] As an example, the position information of the first satellite and the second satellite may be determined by ephemeris information (ephemerisInfo), and the movement information of the second satellite may be determined by PVT information.

[0211] As an example, the offset parameters corresponding to the first satellite and the second satellite may refer to the offset parameter corresponding to the first satellite and the offset parameter corresponding to the second satellite. The offset parameter may be configuration information for switching. For example, the offset parameter may be K configured by the network where the satellite is located for determining the uplink timing. offset .

[0212] In some embodiments, the first offset can be determined based on the offset parameters of the two satellites. As an example, the offset parameters corresponding to the first satellite include a second offset for determining the uplink timing, and the offset parameters corresponding to the second satellite include a third offset for determining the uplink timing, and the first offset is determined based on the difference between the second offset and the third offset. For example, when the first resource domain and the second resource domain are the first SMTC window (SMTC1) and the second SMTC window (SMTC2), respectively, when the second offset is the K corresponding to the first satellite, offset1 , the third offset is K corresponding to the second satellite offset2 When SMTC2=SMTC1+|K offset1 -K offset2 |.

[0213] In some embodiments, the first offset may be determined based on a difference in propagation delay between the terminal device and the first satellite and the second satellite. Because the distances from the first satellite and the second satellite to the terminal device may be different, there may be a difference in propagation delay between the terminal device and the first satellite and the second satellite.

[0214] As an example, the propagation delay difference can be determined in various ways. For example, the propagation delay difference can be determined based on position information of the terminal device, the first satellite, and the second satellite. For example, the propagation delay difference can also be determined based on movement information of the first satellite and the second satellite.

[0215] As an example, the first offset may be the product of a first time constant L and a first coefficient K. The time unit of the first time constant may be determined based on the time unit of the resource domain. The first coefficient may be determined based on the distance or direction angle between the terminal device and the two satellites.

[0216] For example, when the resource domain is a measurement window of SMTC, the length unit of the value of L may depend on the measurement unit of the measurement window of SMTC. When the measurement window is in symbols, the value of L is in symbols; when the measurement window is in slots, the value of L is in slots.

[0217] As an implementation, the position information of the first satellite and the terminal device can determine a first bearing angle between the first satellite and the terminal device, and the position information of the second satellite and the terminal device can determine a second bearing angle between the second satellite and the terminal device. The first offset can be determined based on the first bearing angle and the second bearing angle. The bearing angle can be the angle between a line connecting the satellite and the terminal device and a perpendicular line between the satellite and the ground.

[0218] For ease of understanding, the following still uses SMTC1 and SMTC2 as examples, and with reference to FIG7 , illustrates a method for determining the first offset. For the sake of brevity, the terms explained in FIG4 will not be repeated. Referring to FIG7 , the first direction angle between the first satellite 710 and the terminal device 730 is δ1, and the second direction angle between the second satellite 720 and the terminal device 730 is δ2. SMTC1 and SMTC2 can be determined according to the following formula:

[0219] SMTC2 = SMTC1 + K × L, where K × L is the first offset and K can be expressed as:

[0220] As an implementation method, the position information of the first satellite and the terminal device can determine the first distance between the first satellite and the terminal device, and the position information of the second satellite and the terminal device can determine the second distance between the second satellite and the terminal device, and the first offset can be determined based on the first distance and the second distance.

[0221] SMTC1 and SMTC2 are still used as an example, and are described in conjunction with Figure 7. Referring to Figure 7, when the first distance between the first satellite 710 and the terminal device 730 is D1 and the second distance between the second satellite 720 and the terminal device 730 is D2, the ratio of D1 to D2 can be used as the coefficient K of the first offset. That is, in SMTC2 = SMTC1 + K × L, K can be expressed as:

[0222] As an example, in some embodiments, the first offset may be determined based on a distance between the first satellite and the second satellite based on a trajectory and satellite movement information. That is, the first offset may be related to the trajectory distance and movement speed between the current positions of the first satellite and the second satellite. The trajectory distance may be the distance the second satellite would travel along the trajectory from its current position to the current position of the first satellite.

[0223] Exemplarily, the position of the first satellite at the current moment is the first position, the position of the second satellite at the current moment is the second position, and the first offset can be determined based on the time it takes for the second satellite to move from the second position to the first position.

[0224] Exemplarily, the first offset may be the time taken for the second satellite to move from its current position to the current position of the first satellite along the moving trajectory.

[0225] For ease of understanding, another method for determining the first offset is illustrated below with reference to FIG8 . For the sake of brevity, terminology previously explained in FIG4 or FIG7 will not be repeated. Referring to FIG8 , when the track distance between first satellite 810 and second satellite 820 is D and the velocity of the second satellite is V2, the first offset Δ can be expressed as: Δ = D / |V2|.

[0226] The above description, combined with Figures 7 and 8, describes various methods for determining the first offset. Within a serving cell, a terminal device can determine the first resource region corresponding to the first satellite and then determine the second resource region based on the first resource region and the first offset. Based on the determined second resource region, the terminal device can not only search for the synchronization signal of the second satellite in a targeted manner, but also prevent the synchronization signal of the first satellite from interfering with the handover process, thereby improving handover efficiency.

[0227] The method and possible implementation methods of the embodiments of the present application are described above with reference to Figures 5 to 8 . To better understand the present application, the following describes the embodiment of the present application in detail with reference to Figure 9 , taking the example of a first satellite and a second satellite connected to the same network device. It should be understood that the method shown in Figure 9 is merely an example and does not limit the embodiments of the present application.

[0228] FIG9 is written from the perspective of the interaction among the terminal device, the first satellite, the second satellite and the network device.

[0229] 9 , in step S910 , the network device transmits data to the first satellite, and the first satellite transmits data to the terminal device, wherein the first satellite acts as a relay between the network device and the terminal device.

[0230] In step S920, the network device transmits an indication / assistance information for unchanged PCI via the first satellite. The first satellite may transmit the information to the terminal device via a broadcast. The indication may include a first handover command. The assistance information may include assistance information related to the second satellite.

[0231] In step S930, the second satellite starts providing service at T-start, where T-start is the second time point.

[0232] In step S940, the terminal device acquires the DL and UL sync to the serving cell via the target satellite. The terminal device accesses the network where the second satellite is located.

[0233] In step S950, the first satellite stops service at T-service. T-service is the first time point. As shown in Figure 9, the second time point is earlier than the first time point. The period from the second time point to the first time point is the overlapping duration of the first and second satellites' overlapping service cells. The terminal device can complete the handover during this overlapping period.

[0234] In step S960, the network device performs data transmission with the second satellite, and the second satellite performs data transmission with the terminal device, wherein the second satellite serves as a relay between the network device and the terminal device.

[0235] The method embodiment of the present application is described in detail above with reference to Figures 1 to 9 . The device embodiment of the present application is described in detail below with reference to Figures 10 to 12 . It should be understood that the description of the device embodiment corresponds to the description of the method embodiment. Therefore, for portions not described in detail, reference can be made to the above method embodiment.

[0236] FIG10 is a schematic block diagram of a terminal device according to an embodiment of the present application. The terminal device 1000 may be any of the terminal devices described above. The terminal device 1000 shown in FIG10 includes a receiving unit 1010 and a detecting unit 1020.

[0237] The receiving unit 1010 may be configured to receive a first switching command, where the first switching command is used to instruct the terminal device to perform switching from the first satellite to the second satellite.

[0238] The detection unit 1020 can be used to detect the first synchronization signal and the second synchronization signal in the first resource domain and the second resource domain respectively; wherein the first resource domain and the second resource domain are determined according to the first information, the first synchronization signal is related to the first satellite, and the second synchronization signal is used for the terminal device to synchronize with the second satellite.

[0239] Optionally, the receiving unit 1010 is further used to receive auxiliary information related to the second satellite sent by the first satellite, where the auxiliary information is used by the terminal device to determine the first information.

[0240] Optionally, the first information is used to indicate a first resource domain, and the second resource domain includes resources other than the first resource domain.

[0241] Optionally, the first resource domain includes a first time window, the second resource domain includes a second time window, the first information is used to indicate the first time window, and the second time window is determined according to the first time window and the first offset.

[0242] Optionally, the first time window is determined according to SMTC, or the first time window and the second time window are determined according to SMTC.

[0243] Optionally, the first offset is determined based on one or more of the following information: propagation delay of the terminal device in communicating with the first satellite and the second satellite respectively; offset parameters corresponding to the first satellite and the second satellite respectively; position information of the first satellite and the second satellite; position information of the terminal device; and movement information of the second satellite.

[0244] Optionally, the offset parameters corresponding to the first satellite include a second offset for determining uplink timing, the offset parameters corresponding to the second satellite include a third offset for determining uplink timing, and the first offset is determined based on the difference between the second offset and the third offset.

[0245] Optionally, the position information of the first satellite and the terminal device is used to determine a first direction angle between the first satellite and the terminal device, the position information of the second satellite and the terminal device is used to determine a second direction angle between the second satellite and the terminal device, and the first offset is determined based on the first direction angle and the second direction angle.

[0246] Optionally, the position of the first satellite at the current moment is the first position, the position of the second satellite at the current moment is the second position, and the first offset is determined according to the time it takes for the second satellite to move from the second position to the first position.

[0247] Optionally, the detection unit 1020 is also used by the terminal device to detect the second synchronization signal within the second time window; the terminal device 1000 also includes an adjustment unit, which can be used to adjust the second time window according to the auxiliary information related to the second satellite when the terminal device cannot detect the second synchronization signal within the second time window; and a sending unit, which can be used to send the adjustment information of the second time window to the network device.

[0248] Optionally, the first information includes a first carrier and a second carrier, the first carrier is related to the first synchronization signal, the second carrier is related to the second synchronization signal, and subcarrier spacings of the first carrier and the second carrier are different.

[0249] Optionally, the first information includes a first parameter, and the bits of the first parameter are bitwise inverted to obtain a second parameter. The first synchronization signal corresponds to a first signal index, and the second synchronization signal corresponds to a second signal index. The first signal index and the second signal index are respectively determined by the first parameter and the second parameter.

[0250] Optionally, the first parameter is inOneGroup.

[0251] Optionally, during switching from the first satellite to the second satellite, the PCI of the service cell where the terminal device is located remains unchanged.

[0252] Optionally, the first handover command includes second information, where the second information is used to indicate that the network device sending the first handover command supports handover with unchanged serving cell PCI.

[0253] Optionally, the first switching command also includes a first time point when the first satellite stops service and a second time point when the terminal device starts to synchronize with the second satellite, the second time point being earlier than the first time point. The terminal device 1000 also includes an execution unit, which can be used to execute the switch from the first satellite to the second satellite within the time period from the second time point to the first time point.

[0254] FIG11 is a schematic block diagram of a network device according to an embodiment of the present application. The network device 1100 may be any of the network devices described above. The network device 1100 shown in FIG11 includes a sending unit 1110.

[0255] The sending unit 1110 can be used to send a first switching command to the terminal device, and the first switching command is used to instruct the terminal device to perform a switch from the first satellite to the second satellite; wherein the second synchronization signal is used for the terminal device to synchronize with the second satellite, the first synchronization signal is related to the first satellite, the first resource domain and the second resource domain are used by the terminal device to detect the first synchronization signal and the second synchronization signal, respectively, and the first resource domain and the second resource domain are determined based on the first information.

[0256] Optionally, the sending unit is further used to send auxiliary information related to the second satellite to the terminal device via the first satellite, and the auxiliary information is used by the terminal device to determine the first information.

[0257] Optionally, the first information is used to indicate a first resource domain, and the second resource domain includes resources other than the first resource domain.

[0258] Optionally, the first resource domain includes a first time window, the second resource domain includes a second time window, the first information is used to indicate the first time window, and the second time window is determined according to the first time window and the first offset.

[0259] Optionally, the first time window is determined according to SMTC, or the first time window and the second time window are determined according to SMTC.

[0260] Optionally, the first offset is determined based on one or more of the following information: propagation delay of the terminal device in communicating with the first satellite and the second satellite respectively; offset parameters corresponding to the first satellite and the second satellite respectively; position information of the first satellite and the second satellite; position information of the terminal device; and movement information of the second satellite.

[0261] Optionally, the offset parameters corresponding to the first satellite include a second offset for determining uplink timing, the offset parameters corresponding to the second satellite include a third offset for determining uplink timing, and the first offset is determined based on the difference between the second offset and the third offset.

[0262] Optionally, the position information of the first satellite and the terminal device is used to determine a first direction angle between the first satellite and the terminal device, the position information of the second satellite and the terminal device is used to determine a second direction angle between the second satellite and the terminal device, and the first offset is determined based on the first direction angle and the second direction angle.

[0263] Optionally, the position of the first satellite at the current moment is the first position, the position of the second satellite at the current moment is the second position, and the first offset is determined according to the time it takes for the second satellite to move from the second position to the first position.

[0264] Optionally, the network device 1100 further includes a receiving unit, configured to receive adjustment information of the second time window sent by the terminal device when the terminal device cannot detect the second synchronization signal within the second time window.

[0265] Optionally, the first information includes a first carrier and a second carrier, the first carrier is related to the first synchronization signal, the second carrier is related to the second synchronization signal, and subcarrier spacings of the first carrier and the second carrier are different.

[0266] Optionally, the first information includes a first parameter, and the bits of the first parameter are bitwise inverted to obtain a second parameter. The first synchronization signal corresponds to a first signal index, and the second synchronization signal corresponds to a second signal index. The first signal index and the second signal index are respectively determined by the first parameter and the second parameter.

[0267] Optionally, the first parameter is inOneGroup.

[0268] Optionally, during switching from the first satellite to the second satellite, the PCI of the service cell where the terminal device is located remains unchanged.

[0269] Optionally, the first handover command includes second information, and the second information is used to indicate that the network device supports handover with unchanged serving cell PCI.

[0270] Optionally, the first switching command further includes a first time point when the first satellite stops serving and a second time point when the terminal device starts synchronizing with the second satellite, and the second time point is earlier than the first time point.

[0271] Figure 12 shows a schematic block diagram of a communication device according to an embodiment of the present application. The dashed lines in Figure 12 indicate that the unit or module is optional. Device 1200 may be used to implement the method described in the above method embodiment. Device 1200 may be a chip, a terminal device, or a network device.

[0272] The device 1200 may include one or more processors 1210. The processor 1210 may support the device 1200 to implement the method described in the above method embodiment. The processor 1210 may be a general-purpose processor or a special-purpose processor. For example, the processor may be a central processing unit (CPU). Alternatively, the processor may be another general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0273] The apparatus 1200 may further include one or more memories 1220. The memories 1220 store programs that can be executed by the processor 1210, causing the processor 1210 to perform the methods described in the above method embodiments. The memories 1220 may be independent of the processor 1210 or integrated into the processor 1210.

[0274] The apparatus 1200 may further include a transceiver 1230. The processor 1210 may communicate with other devices or chips via the transceiver 1230. For example, the processor 1210 may transmit and receive data with other devices or chips via the transceiver 1230.

[0275] The present application also provides a computer-readable storage medium for storing a program. The computer-readable storage medium can be applied to a terminal device or network device provided in the present application, and the program enables a computer to execute the method performed by the terminal device or network device in each embodiment of the present application.

[0276] The computer-readable storage medium may be any available medium that can be read by a computer or a data storage device such as a server or data center that includes one or more available media. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, or a magnetic tape), an optical medium (e.g., a digital versatile disc (DVD)), or a semiconductor medium (e.g., a solid state drive (SSD)).

[0277] The present application also provides a computer program product. The computer program product includes a program. The computer program product can be applied to a terminal device or network device provided in the present application, and the program causes a computer to execute the method performed by the terminal or network device in each embodiment of the present application.

[0278] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0279] The present application also provides a computer program that can be applied to a terminal device or network device provided in the present application, and enables a computer to execute the method performed by the terminal or network device in each embodiment of the present application.

[0280] The terms "system" and "network" in this application may be used interchangeably. In addition, the terms used in this application are only used to explain the specific embodiments of this application and are not intended to limit this application. The terms "first," "second," "third," and "fourth" in the specification and claims of this application and the accompanying drawings are used to distinguish different objects rather than to describe a specific order. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions.

[0281] In the embodiments of this application, the term "indication" may refer to a direct indication, an indirect indication, or an indication of an association. For example, "A indicates B" may refer to a direct indication of B, e.g., B can obtain information through A; it may refer to an indirect indication of B, e.g., A indicates C, e.g., B can obtain information through C; or it may refer to an association between A and B.

[0282] In the embodiments of the present application, the term "corresponding" may indicate a direct or indirect correspondence between the two, or an association relationship between the two, or a relationship between indication and indication, configuration and configuration, etc.

[0283] In the embodiments of the present application, "pre-definition" or "pre-configuration" may be implemented by pre-storing corresponding codes, tables, or other methods that can be used to indicate relevant information in a device (e.g., including a terminal device and a network device). The present application does not limit the specific implementation method. For example, pre-definition may refer to a definition in a protocol.

[0284] In the embodiments of the present application, the "protocol" may refer to a standard protocol in the communication field, for example, it may include an LTE protocol, a NR protocol, and related protocols used in future communication systems, and this application does not limit this.

[0285] In the embodiments of the present application, determining B based on A does not mean determining B only based on A. B can also be determined based on A and / or other information.

[0286] In the embodiments of this application, the term "and / or" is simply a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0287] In various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0288] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0289] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0290] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0291] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A method for wireless communication, characterized in that, comprising: The terminal device receives a first handover command for instructing the terminal device to perform handover from a first satellite to a second satellite; The terminal device respectively detects a first synchronization signal and a second synchronization signal within a first resource domain and a second resource domain; Wherein, the first resource domain and the second resource domain are determined according to first information, the first synchronization signal is related to the first satellite, and the second synchronization signal is used for the terminal device to synchronize with the second satellite.

2. The method according to claim 1, characterized in that, The method further comprises: The terminal device receives auxiliary information related to the second satellite sent by the first satellite, and the auxiliary information is used for the terminal device to determine the first information.

3. The method according to claim 1 or 2, characterized in that, The first information is used to indicate the first resource domain, and the second resource domain includes resources other than the first resource domain.

4. The method according to claim 1 or 2, characterized in that, The first resource domain includes a first time window, the second resource domain includes a second time window, the first information is used to indicate the first time window, and the second time window is determined according to the first time window and a first offset.

5. The method according to claim 4, characterized in that, The first time window is determined according to the SSB measurement timing configuration SMTC, or the first time window and the second time window are determined according to the SMTC.

6. The method according to claim 4 or 5, characterized in that, The first offset is determined according to one or more of the following information: The propagation delays of the terminal device communicating with the first satellite and the second satellite respectively; Offset parameters corresponding to the first satellite and the second satellite respectively; The position information of the first satellite and the second satellite; The position information of the terminal device; The movement information of the second satellite.

7. The method according to claim 6, characterized in that, The offset parameter corresponding to the first satellite includes a second offset for determining uplink timing, the offset parameter corresponding to the second satellite includes a third offset for determining uplink timing, and the first offset is determined according to the difference between the second offset and the third offset.

8. The method according to claim 6, characterized in that, The position information of the first satellite and the terminal device is used to determine a first direction angle between the first satellite and the terminal device, the position information of the second satellite and the terminal device is used to determine a second direction angle between the second satellite and the terminal device, and the first offset is determined according to the first direction angle and the second direction angle.

9. The method according to claim 6, characterized in that, The position of the first satellite at the current moment is a first position, the position of the second satellite at the current moment is a second position, and the first offset is determined according to the time for the second satellite to move from the second position to the first position.

10. The method according to any one of claims 4 - 9, wherein, the method further includes: the terminal device detecting the second synchronization signal within the second time window; when the terminal device fails to detect the second synchronization signal within the second time window, the terminal device adjusting the second time window according to auxiliary information related to the second satellite; the terminal device sending adjustment information of the second time window to the network device.

11. The method according to claim 1 or 2, wherein, the first information includes a first carrier and a second carrier, the first carrier is related to the first synchronization signal, the second carrier is related to the second synchronization signal, and the sub - carrier spacing of the first carrier and the second carrier is different.

12. The method according to claim 1 or 2, wherein, the first information includes a first parameter, taking the bitwise inversion of the bits of the first parameter to obtain a second parameter, the first synchronization signal corresponds to a first signal index, the second synchronization signal corresponds to a second signal index, and the first signal index and the second signal index are determined by the first parameter and the second parameter respectively.

13. The method according to claim 12, wherein, the first parameter is inOneGroup.

14. The method according to any one of claims 1 - 13, wherein, during the handover from the first satellite to the second satellite, the physical cell identifier (PCI) of the serving cell where the terminal device is located remains unchanged.

15. The method according to claim 14, wherein, the first handover command includes second information, and the second information is used to indicate that the network device sending the first handover command supports the handover with the serving cell PCI unchanged.

16. The method according to any one of claims 1 - 15, wherein, the first handover command further includes a first time point when the first satellite stops serving and a second time point when the terminal device starts synchronizing with the second satellite, the second time point is earlier than the first time point, and the method further includes: the terminal device performing the handover from the first satellite to the second satellite during the time period from the second time point to the first time point.

17. A method for wireless communication, wherein, it includes: the network device sending a first handover command to the terminal device, and the first handover command is used to instruct the terminal device to perform a handover from the first satellite to the second satellite; wherein, the second synchronization signal is used for the terminal device to synchronize with the second satellite, the first synchronization signal is related to the first satellite, the first resource domain and the second resource domain are respectively used for the terminal device to detect the first synchronization signal and the second synchronization signal, and the first resource domain and the second resource domain are determined according to the first information.

18. The method according to claim 17, wherein, the method further includes: The network device sends auxiliary information related to the second satellite to the terminal device via the first satellite, and the auxiliary information is used for the terminal device to determine the first information.

19. The method according to claim 17 or 18, wherein, the first information is used to indicate the first resource domain, and the second resource domain includes resources other than the first resource domain.

20. The method according to claim 17 or 18, wherein, the first resource domain includes a first time window, the second resource domain includes a second time window, the first information is used to indicate the first time window, and the second time window is determined according to the first time window and a first offset.

21. The method according to claim 20, wherein, the first time window is determined according to the SSB measurement timing configuration (SMTC), or the first time window and the second time window are determined according to the SMTC.

22. The method according to claim 20 or 21, wherein, the first offset is determined according to one or more of the following information: the propagation delays of the terminal device communicating with the first satellite and the second satellite respectively; the offset parameters corresponding to the first satellite and the second satellite respectively; the position information of the first satellite and the second satellite; the position information of the terminal device; the movement information of the second satellite.

23. The method according to claim 22, wherein, the offset parameter corresponding to the first satellite includes a second offset for determining uplink timing, the offset parameter corresponding to the second satellite includes a third offset for determining uplink timing, and the first offset is determined according to the difference between the second offset and the third offset.

24. The method according to claim 22, wherein, the position information of the first satellite and the terminal device is used to determine a first direction angle between the first satellite and the terminal device, the position information of the second satellite and the terminal device is used to determine a second direction angle between the second satellite and the terminal device, and the first offset is determined according to the first direction angle and the second direction angle.

25. The method according to claim 22, wherein, the position of the first satellite at the current moment is a first position, the position of the second satellite at the current moment is a second position, and the first offset is determined according to the time for the second satellite to move from the second position to the first position.

26. The method according to any one of claims 20-25, wherein, the method further includes: when the terminal device cannot detect the second synchronization signal within the second time window, the network device receives the adjustment information of the second time window sent by the terminal device.

27. The method according to claim 17 or 18, wherein, The first information includes a first carrier and a second carrier. The first carrier is related to the first synchronization signal, and the second carrier is related to the second synchronization signal. The subcarrier spacing of the first carrier and the second carrier is different.

28. The method according to claim 17 or 18, wherein, the first information includes a first parameter, and the bits of the first parameter are bitwise inverted to obtain a second parameter. The first synchronization signal corresponds to a first signal index, and the second synchronization signal corresponds to a second signal index. The first signal index and the second signal index are determined by the first parameter and the second parameter respectively.

29. The method according to claim 28, wherein, the first parameter is inOneGroup.

30. The method according to any one of claims 17-29, wherein, in the handover from the first satellite to the second satellite, the physical cell identifier (PCI) of the serving cell where the terminal device is located remains unchanged.

31. The method according to claim 30, wherein, the first handover command includes second information, and the second information is used to indicate that the network device supports the handover with the serving cell PCI unchanged.

32. The method according to any one of claims 17-31, wherein, the first handover command further includes a first time point when the first satellite stops serving and a second time point when the terminal device starts to synchronize with the second satellite, and the second time point is earlier than the first time point.

33. A terminal device, wherein, comprises: a receiving unit, configured to receive a first handover command, where the first handover command is used to instruct the terminal device to perform a handover from a first satellite to a second satellite; a detecting unit, configured to detect a first synchronization signal and a second synchronization signal in a first resource domain and a second resource domain respectively; wherein, the first resource domain and the second resource domain are determined according to first information, the first synchronization signal is related to the first satellite, and the second synchronization signal is used for the terminal device to synchronize with the second satellite.

34. The terminal device according to claim 33, wherein, the receiving unit is further configured to receive auxiliary information related to the second satellite sent by the first satellite, and the auxiliary information is used for the terminal device to determine the first information.

35. The terminal device according to claim 33 or 34, wherein, the first information is used to indicate the first resource domain, and the second resource domain includes resources other than the first resource domain.

36. The terminal device according to claim 33 or 34, wherein, the first resource domain includes a first time window, the second resource domain includes a second time window, the first information is used to indicate the first time window, and the second time window is determined according to the first time window and a first offset.

37. The terminal device according to claim 36, wherein, The first time window is determined according to the SMTC configured by the SSB measurement timing, or the first time window and the second time window are determined according to the SMTC.

38. The terminal device according to claim 36 or 37, wherein, the first offset is determined according to one or more of the following information: the propagation delays of the terminal device communicating with the first satellite and the second satellite respectively; the offset parameters corresponding to the first satellite and the second satellite respectively; the position information of the first satellite and the second satellite; the position information of the terminal device; the movement information of the second satellite.

39. The terminal device according to claim 38, wherein, the offset parameter corresponding to the first satellite includes a second offset for determining the uplink timing, the offset parameter corresponding to the second satellite includes a third offset for determining the uplink timing, and the first offset is determined according to the difference between the second offset and the third offset.

40. The terminal device according to claim 38, wherein, the position information of the first satellite and the terminal device is used to determine a first direction angle between the first satellite and the terminal device, the position information of the second satellite and the terminal device is used to determine a second direction angle between the second satellite and the terminal device, and the first offset is determined according to the first direction angle and the second direction angle.

41. The terminal device according to claim 38, wherein, the position of the first satellite at the current moment is a first position, the position of the second satellite at the current moment is a second position, and the first offset is determined according to the time for the second satellite to move from the second position to the first position.

42. The terminal device according to any one of claims 36-41, wherein, the detection unit is further used for the terminal device to detect the second synchronization signal within the second time window; the terminal device further includes: an adjustment unit, configured to adjust the second time window according to the auxiliary information related to the second satellite when the terminal device fails to detect the second synchronization signal within the second time window; a sending unit, configured to send the adjustment information of the second time window to the network device.

43. The terminal device according to claim 33 or 34, wherein, the first information includes a first carrier and a second carrier, the first carrier is related to the first synchronization signal, the second carrier is related to the second synchronization signal, and the subcarrier spacing of the first carrier and the second carrier is different.

44. The terminal device according to claim 33 or 34, wherein, the first information includes a first parameter, the bitwise inversion of the bits of the first parameter is used to obtain a second parameter, the first synchronization signal corresponds to a first signal index, the second synchronization signal corresponds to a second signal index, and the first signal index and the second signal index are determined by the first parameter and the second parameter respectively.

45. The terminal device according to claim 44, wherein, The first parameter is inOneGroup.

46. The terminal device according to any one of claims 33-45, wherein, in the handover from the first satellite to the second satellite, the physical cell identifier (PCI) of the serving cell where the terminal device is located remains unchanged.

47. The terminal device according to claim 46, wherein, the first handover command includes second information, and the second information is used to indicate that the network device sending the first handover command supports the handover with the serving cell PCI unchanged.

48. The terminal device according to any one of claims 33-47, wherein, the first handover command further includes a first time point when the first satellite stops serving and a second time point when the terminal device starts to synchronize with the second satellite, the second time point is earlier than the first time point, and the terminal device further includes: an execution unit, configured to perform the handover from the first satellite to the second satellite during the period from the second time point to the first time point.

49. A network device, wherein, it includes: a sending unit, configured to send a first handover command to a terminal device, and the first handover command is used to instruct the terminal device to perform a handover from a first satellite to a second satellite; wherein, a second synchronization signal is used for the terminal device to synchronize with the second satellite, a first synchronization signal is related to the first satellite, a first resource domain and a second resource domain are respectively used for the terminal device to detect the first synchronization signal and the second synchronization signal, and the first resource domain and the second resource domain are determined according to first information.

50. The network device according to claim 49, wherein, the sending unit is further configured to send auxiliary information related to the second satellite to the terminal device through the first satellite, and the auxiliary information is used for the terminal device to determine the first information.

51. The network device according to claim 49 or 50, wherein, the first information is used to indicate the first resource domain, and the second resource domain includes resources other than the first resource domain.

52. The network device according to claim 49 or 50, wherein, the first resource domain includes a first time window, the second resource domain includes a second time window, the first information is used to indicate the first time window, and the second time window is determined according to the first time window and a first offset.

53. The network device according to claim 52, wherein, the first time window is determined according to the SSB measurement timing configuration (SMTC), or the first time window and the second time window are determined according to the SMTC.

54. The network device according to claim 52 or 53, wherein, the first offset is determined according to one or more of the following information: the propagation delays of the terminal device communicating with the first satellite and the second satellite respectively; the offset parameters corresponding to the first satellite and the second satellite respectively; the position information of the first satellite and the second satellite; the position information of the terminal device; The movement information of the second satellite.

55. The network device according to claim 54, wherein, the offset parameter corresponding to the first satellite includes a second offset for determining uplink timing, the offset parameter corresponding to the second satellite includes a third offset for determining uplink timing, and the first offset is determined according to the difference between the second offset and the third offset.

56. The network device according to claim 54, wherein, the position information of the first satellite and the terminal device is used to determine a first direction angle between the first satellite and the terminal device, the position information of the second satellite and the terminal device is used to determine a second direction angle between the second satellite and the terminal device, and the first offset is determined according to the first direction angle and the second direction angle.

57. The network device according to claim 54, wherein, the position of the first satellite at the current moment is a first position, the position of the second satellite at the current moment is a second position, and the first offset is determined according to the time for the second satellite to move from the second position to the first position.

58. The network device according to any one of claims 52-57, wherein, the network device further includes: a receiving unit, configured to receive the adjustment information of the second time window sent by the terminal device when the terminal device fails to detect the second synchronization signal within the second time window.

59. The network device according to claim 49 or 50, wherein, the first information includes a first carrier and a second carrier, the first carrier is related to the first synchronization signal, the second carrier is related to the second synchronization signal, and the subcarrier spacing of the first carrier and the second carrier is different.

60. The network device according to claim 49 or 50, wherein, the first information includes a first parameter, and the second parameter is obtained by taking the bitwise inversion of the bits of the first parameter. The first synchronization signal corresponds to a first signal index, the second synchronization signal corresponds to a second signal index, and the first signal index and the second signal index are determined by the first parameter and the second parameter respectively.

61. The network device according to claim 60, wherein, the first parameter is inOneGroup.

62. The network device according to any one of claims 49-61, wherein, in the handover from the first satellite to the second satellite, the physical cell identifier (PCI) of the serving cell where the terminal device is located remains unchanged.

63. The network device according to claim 62, wherein, the first handover command includes second information, and the second information is used to indicate that the network device supports handover with unchanged serving cell PCI.

64. The network device according to any one of claims 49-63, wherein, The first handover command further includes a first time point when the first satellite stops service and a second time point when the terminal device starts to synchronize with the second satellite, and the second time point is earlier than the first time point.

65. A communication device, characterized in that, it includes a memory and a processor, the memory is used for storing programs, and the processor is used for calling the programs in the memory to execute the method according to any one of claims 1-32.

66. A device, characterized in that, it includes a processor, which is used for calling a program from a memory to execute the method according to any one of claims 1-32.

67. A chip, characterized in that, it includes a processor, which is used for calling a program from a memory, so that a device installed with the chip executes the method according to any one of claims 1-32.

68. A computer-readable storage medium, characterized in that, a program is stored thereon, and the program enables a computer to execute the method according to any one of claims 1-32.

69. A computer program product, characterized in that, it includes a program, and the program enables a computer to execute the method according to any one of claims 1-32.

70. A computer program, characterized in that, the computer program enables a computer to execute the method according to any one of claims 1-32.

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