Communication method and device

Abstract

The embodiment of the invention provides a communication method and device. The method comprises the steps that terminal equipment sends first random access information to a first satellite; the first random access information is used for requesting to access the first satellite; the terminal device receives first indication information; the first indication information is sent under the condition that the first satellite cannot serve the terminal equipment, and the first indication information is used for indicating the terminal equipment to access a second satellite. Through the method, under the condition that the source satellite cannot serve the terminal equipment, the terminal equipment is requested to access the target satellite, so that the terminal equipment can realize communication by accessing the target satellite.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a communication method and device. Background Art

[0002] In satellite communications, due to the complex space environment, some scenarios are prone to occur, resulting in the source satellite accessed by the terminal device being unable to serve the terminal device. For example, 1) Scenario 1: The source satellite encounters a geosynchronous earth orbit (GEO) satellite and needs to avoid interference and shut down the beam; 2) Scenario 2: The source satellite moves to the Earth's polar region and needs to shut down the satellite, or shut down some of the beams in the satellite; 3) Scenario 3: Tracking, telemetry and command (TT&C) instructs the source satellite to adjust its attitude, change its working mode, etc. These will cause the source satellite to be unable to continue to provide services to the terminal device, so it is necessary to request access to a new satellite for the terminal device to achieve communication.

[0003] However, the current random access technology of the new radio (NR) is completed within a base station, and there is no random access process across base stations. Therefore, for the scenario where the source satellite can no longer serve the terminal device, how to achieve cross-satellite access for the terminal device is one of the problems that need to be solved urgently. Summary of the invention

[0004] The present application proposes a communication method and apparatus, which can effectively implement cross-satellite access for terminal equipment.

[0005] In a first aspect, the present application provides a communication method, which can be executed by a terminal device or by a chip or chip system corresponding to the terminal device, without limitation. The method can specifically include: sending a first random access message to a first satellite; the first random access message is used to request access to the first satellite; receiving a first indication message; the first indication message is sent when the first satellite cannot serve the terminal device, and the first indication message is used to instruct the terminal device to access a second satellite.

[0006] In an embodiment of the present application, the first satellite mentioned above can be regarded as a source satellite to be accessed by the terminal device (or a source satellite that has been accessed), and the second satellite can be regarded as a target satellite to be accessed by the terminal device. The first satellite and the second satellite are not the same satellite, and the types of the first satellite and the second satellite can be the same or different, which is not limited in the present application. However, in some special cases or scenarios, the first satellite and the second satellite can also be the same satellite.

[0007] In the solution of the present application, a terminal device sends a first random access message to a source satellite, and the first random access message is used to request access to the first satellite; when the first satellite cannot serve the terminal device, the terminal device receives a first indication message, and the first indication message is used to instruct the terminal device to access a second satellite, so that the terminal device can access the second satellite across satellites to achieve subsequent communications.

[0008] In a possible implementation manner, the receiving the first indication information includes: receiving the first indication information from the first satellite; or receiving the first indication information from the second satellite.

[0009] In the embodiment of the present application, the terminal device may also receive the first indication information through a third-party communication device (such as other satellites except the first satellite and the second satellite). The present application does not limit the specific path for the terminal device to receive the first indication information.

[0010] Through this implementation, the terminal device can flexibly receive the first indication information, and then execute the subsequent inter-satellite access process based on the first indication information.

[0011] In a possible implementation, the first indication information is scrambled downlink control information; the scrambled downlink control information is obtained by scrambling the first downlink control information according to the random access radio network temporary identifier RA-RNTI of the first satellite, and a newly added first bit information in the first downlink control information is used to indicate the identification information of the second satellite; or, the scrambled downlink control information is obtained by scrambling the downlink control information according to the RA-RNTI of the first satellite and the identification information of the second satellite.

[0012] Through this implementation, the encrypted downlink control information can be designed to instruct the terminal device to access the second satellite, thereby ensuring that the terminal device can achieve communication by accessing the second satellite across satellites.

[0013] In a possible implementation, the first indication information is first random access response information used to respond to the first random access information; the reserved bit information in the first random access response information is used to indicate that the first random access response information is random access response information for inter-satellite access, and the timing advance information field in the first random access response information is used to indicate the identification information of the second satellite.

[0014] Through this implementation, the first random access response information designed to respond to the first random access information can be used to instruct the terminal device to access the second satellite, thereby ensuring that the terminal device can achieve communication through inter-satellite access to the second satellite.

[0015] In a possible implementation, the method further includes: acquiring a common TA of the second satellite; acquiring a downlink timing of the first satellite and a downlink timing of the second satellite; determining a target TA of the second satellite according to the common TA of the second satellite, the downlink timing of the first satellite and the downlink timing of the second satellite; and accessing the second satellite based on the target TA of the second satellite.

[0016] Through this implementation, the terminal device can accurately obtain the target TA of the second satellite, and then based on the target TA of the second satellite, can effectively access the second satellite to achieve communication.

[0017] In a possible implementation manner, the target TA of the second satellite satisfies the following formula:

[0018] T TA =(N TA,UE-specfic +N TA,common +N TA,offset )×T C +2×(DL1-DL2);

[0019] Among them, T TA represents the target TA of the second satellite, N TA,UE-specfic represents the TA of the first satellite, where the TA of the first satellite is determined according to the ephemeris information of the first satellite and the location information of the terminal device; N TA,common represents the common TA of the second satellite, N TA,offset Indicates the preset offset, T C is the minimum time unit, DL1 is the downlink timing of the first satellite, and DL2 is the downlink timing of the second satellite.

[0020] Through this implementation, the terminal device can effectively and accurately calculate the target TA of the second satellite.

[0021] In a possible implementation, obtaining the downlink timing of the first satellite and the downlink timing of the second satellite includes: receiving a synchronization signal of the first satellite and a synchronization signal of the second satellite, respectively, the synchronization signal of the first satellite carrying the downlink timing of the first satellite, and the synchronization signal of the second satellite carrying the downlink timing of the second satellite.

[0022] Through this implementation, the terminal device can effectively obtain the downlink timing of the first satellite and the downlink timing of the second satellite.

[0023] In a possible implementation, the first indication information is first random access response information used to respond to the first random access information; the temporary cell TC-RNTI information field in the first random access response information is used to indicate the identification information of the second satellite; or a new second bit information is added to the first random access response information to indicate the identification information of the second satellite.

[0024] Through this implementation, the first random access response information used to respond to the first random access information can be effectively used to instruct the terminal device to access the second satellite, thereby ensuring that the terminal device achieves communication through inter-satellite access to the second satellite.

[0025] In a possible implementation, the first random access response information also includes the first TA of the second satellite, the first TA of the second satellite is equal to the TA of the first satellite, or the first TA of the second satellite is determined based on the TA of the first satellite and the timing difference between the first satellite and the second satellite; the method also includes: acquiring the common TA of the second satellite; obtaining the target TA of the second satellite based on the first TA of the second satellite and the common TA of the second satellite; and accessing the second satellite based on the target TA of the second satellite.

[0026] Through this implementation, when the terminal device can obtain the first TA of the second satellite, it can use the existing formula (ie, the formula for calculating the TA of the second satellite) to effectively calculate the target TA of the second satellite.

[0027] In a possible implementation manner, the target TA of the second satellite satisfies the following formula:

[0028] T TA =(N TA,UE-specfic +N TA +N TA,common +N TA,offset )×T C ;

[0029] T TA represents the target TA of the second satellite; N TA,UE-specfic represents a second TA of the second satellite, where the second TA of the second satellite is determined according to the ephemeris information of the second satellite and the location information of the terminal device; N TA represents the first TA of the second satellite; N TA,common N represents the common TA of the second satellite; TA,offset Indicates the preset offset, T C The minimum time unit.

[0030] Through this implementation, the terminal device can effectively and accurately calculate the target TA of the second satellite.

[0031] In a possible implementation, acquiring the public TA of the second satellite includes: receiving a broadcast signal of the second satellite, where the broadcast signal of the second satellite carries the public TA of the second satellite.

[0032] Through this implementation, the terminal device can effectively obtain the public TA of the second satellite.

[0033] In a second aspect, the present application provides a communication method, which can be executed by a first satellite, or by a chip or chip system corresponding to the first satellite, without limitation. The method can specifically include: receiving a first random access message from a terminal device; the first random access message is used to request access to the first satellite; determining that the terminal device cannot be served, and sending a first request message to a second satellite, the first request message is used to request the terminal device to access the second satellite.

[0034] In the scheme of the present application, a first satellite receives first random access information from a terminal device, and the first random access information is used to request access to the first satellite; when the first satellite determines that it cannot serve the terminal device, it sends a first request information to the second satellite to request the terminal device to access the second satellite, so that the terminal device can achieve communication by accessing the second satellite.

[0035] In a possible implementation, the method further includes: receiving first response information from the second satellite, where the first response information is used to indicate that the second satellite allows the terminal device to access.

[0036] Through this implementation, the first satellite can ensure that the terminal device can effectively access the second satellite later.

[0037] In a possible implementation, the method further includes: sending first indication information to the terminal device, where the first indication information is used to instruct the terminal device to access the second satellite.

[0038] Through this implementation, the first satellite can effectively instruct the terminal device to access the second satellite across satellites.

[0039] In a possible implementation, the first indication information is scrambled downlink control information; the scrambled downlink control information is obtained by scrambling the first downlink control information according to the random access radio network temporary identifier RA-RNTI of the first satellite, and the first bit information newly added in the first downlink control information is used to indicate the identification information of the second satellite; or the scrambled downlink control information is obtained by scrambling the downlink control information according to the RA-RNTI of the first satellite and the identification information of the second satellite.

[0040] Through this implementation, the scrambled downlink control information can be designed to effectively instruct the terminal device to access the second satellite.

[0041] In a possible implementation, the first indication information is first random access response information used to respond to the first random access information; the reserved bit information in the first random access response information is used to indicate that the first random access response information is random access response information for inter-satellite access, and the timing advance information field in the first random access response information is used to indicate the identification information of the second satellite.

[0042] Through this implementation, the first random access response information designed to respond to the first random access information can be effectively used to instruct the terminal device to access the second satellite.

[0043] In a possible implementation, the first indication information is first random access response information used to respond to the first random access information; the temporary cell TC-RNTI information field in the first random access response information is used to indicate the identification information of the second satellite; or a new second bit information is added to the first random access response information to indicate the identification information of the second satellite.

[0044] Through this implementation, the first random access response information used to respond to the first random access information can be used to effectively instruct the terminal device to access the second satellite.

[0045] In a possible implementation, the first random access response information also includes a first TA of the second satellite; wherein the first TA of the second satellite is equal to the TA of the first satellite, or the first TA of the second satellite is determined based on the TA of the first satellite and the timing difference between the first satellite and the second satellite.

[0046] Through this implementation, the first TA of the second satellite is effectively provided to the terminal device, so that the terminal device can accurately calculate the target TA of the second satellite based on the first TA of the second satellite and using an existing formula.

[0047] In a third aspect, the present application provides a communication method, which can be executed by a second satellite, or by a chip or chip system corresponding to the second satellite, without limitation. The method may specifically include: receiving a first request message from a first satellite; the first request message is used to request a terminal device to access the second satellite; the first request message is sent by the first satellite to the second satellite when the first satellite receives a first random access message from the terminal device and determines that the terminal device cannot be served; the first random access message is used by the terminal device to request access to the first satellite; and the terminal device is allowed to access.

[0048] In the present application scheme, the second satellite receives a first request message from the first satellite, the first request message is used to request the terminal device to access the second satellite; the first request message is sent to the second satellite by the first satellite when the first satellite receives the first random access message from the terminal device and determines that the terminal device cannot be served; the first random access message is used by the terminal device to request access to the first satellite; the second satellite allows the terminal device to access. Through this method, when the first satellite cannot continue to serve the terminal device, the terminal device can effectively access the second satellite across satellites, thereby achieving communication.

[0049] In a possible implementation, the method further includes: sending a first response message to the first satellite, so that the first satellite sends a first indication message to the terminal device after receiving the first response message; or sending the first indication message to the terminal device; wherein the first indication message is used to instruct the terminal device to access the second satellite.

[0050] Through this implementation, the terminal device can effectively obtain the first indication information, and then execute the subsequent process of accessing the second satellite.

[0051] In a possible implementation, the first indication information is scrambled downlink control information; the scrambled downlink control information is obtained by scrambling the first downlink control information according to the random access radio network temporary identifier RA-RNTI of the first satellite, and the first bit information newly added in the first downlink control information is used to indicate the identification information of the second satellite; or the scrambled downlink control information is obtained by scrambling the downlink control information according to the RA-RNTI of the first satellite and the identification information of the second satellite.

[0052] Through this implementation, the scrambled downlink control information can be designed to effectively instruct the terminal device to access the second satellite.

[0053] In a possible implementation, the first indication information is first random access response information used to respond to the first random access information; the reserved bit information in the first random access response information is used to indicate that the first random access response information is random access response information for inter-satellite access, and the timing advance information field in the first random access response information is used to indicate the identification information of the second satellite.

[0054] Through this implementation, the first random access response information designed to respond to the first random access information can be effectively used to instruct the terminal device to access the second satellite.

[0055] In a possible implementation, the first indication information is first random access response information used to respond to the first random access information; the temporary cell TC-RNTI information field in the first random access response information is used to indicate the identification information of the second satellite; or a new second bit information is added to the first random access response information to indicate the identification information of the second satellite.

[0056] Through this implementation, the first random access response information used to respond to the first random access information can be used to effectively instruct the terminal device to access the second satellite.

[0057] In a possible implementation, the first random access response information also includes a first TA of the second satellite; wherein the first TA of the second satellite is equal to the TA of the first satellite, or the first TA of the second satellite is determined based on the TA of the first satellite and the timing difference between the first satellite and the second satellite.

[0058] Through this implementation, the first TA of the second satellite is effectively provided to the terminal device, so that the terminal device can accurately calculate the target TA of the second satellite based on the first TA of the second satellite and using the existing formula.

[0059] In a fourth aspect, an embodiment of the present application also provides a communication device, which can be used to execute the method of the first aspect. The device may be a terminal device, or the device may be a component in the terminal device (for example, a chip, or a chip system, or a circuit), or may be a device that can be used in conjunction with the terminal device.

[0060] In one possible implementation, the device may include a module or unit corresponding to the method / operation / step / action described in the first aspect, and the module or unit may be a hardware circuit, or software, or a combination of a hardware circuit and software. In one possible implementation, the device may include a processing unit (also referred to as a processing module) and a communication unit (also referred to as a communication module), wherein the communication unit may be used to perform the functions of receiving and / or sending, and the processing unit may be used to perform the method described in the first aspect or any possible implementation of the first aspect.

[0061] In the fifth aspect, an embodiment of the present application also provides a communication device, which can be used to execute the method of the second aspect. The device may be a first satellite, or the device may be a component in the first satellite (for example, a chip, or a chip system, or a circuit), or may be a device that can be used in conjunction with the first satellite.

[0062] In one possible implementation, the device may include a module or unit corresponding to the method / operation / step / action described in the second aspect, and the module or unit may be a hardware circuit, or software, or a combination of a hardware circuit and software. In one possible implementation, the device may include a processing unit (also referred to as a processing module) and a communication unit (also referred to as a communication module), wherein the communication unit may be used to perform the functions of receiving and / or sending, and the processing unit may be used to perform the method described in the second aspect or any possible implementation of the second aspect.

[0063] In the sixth aspect, an embodiment of the present application also provides a communication device, which can be used to execute the method of the third aspect. The device may be a second satellite, or the device may be a component in the second satellite (for example, a chip, or a chip system, or a circuit), or may be a device that can be used in combination with the second satellite.

[0064] In one possible implementation, the device may include a module or unit corresponding to the method / operation / step / action described in the third aspect, and the module or unit may be a hardware circuit, or software, or a combination of a hardware circuit and software. In one possible implementation, the device may include a processing unit (also referred to as a processing module) and a communication unit (also referred to as a communication module), wherein the communication unit may be used to perform the functions of receiving and / or sending, and the processing unit may be used to perform the method described in the third aspect or any possible implementation of the third aspect.

[0065] In the seventh aspect, a communication device is provided in an embodiment of the present application, and the device includes: at least one processor and a communication interface; wherein the communication interface is used to communicate with other devices; the processor is used to run a set of programs so that the device can implement the method provided in the above-mentioned first aspect or any possible implementation method thereof.

[0066] In an eighth aspect, a communication device is provided in an embodiment of the present application, the device comprising: at least one processor and a communication interface; wherein the communication interface is used to communicate with other devices; the processor is used to run a set of programs so that the device can implement the method provided in the above-mentioned second aspect or any possible implementation method thereof.

[0067] In the ninth aspect, an embodiment of the present application provides a device, which includes: at least one processor and a communication interface; wherein the communication interface is used to communicate with other devices; the processor is used to run a set of programs so that the device can implement the method provided in the third aspect above or any possible implementation method thereof.

[0068] In the tenth aspect, an embodiment of the present application also provides a computer storage medium, which stores a software program. When the software program is read and executed by one or more processors, it can implement the method provided by the above-mentioned first aspect or any possible implementation method thereof, or implement the method provided by the above-mentioned second aspect or any possible implementation method thereof, or implement the method provided by the above-mentioned third aspect or any possible implementation method thereof.

[0069] In the eleventh aspect, an embodiment of the present application also provides a computer program product comprising instructions, which, when executed on a computer, enables the method provided by the first aspect or any possible implementation thereof to be executed, or enables the method provided by the second aspect or any possible implementation thereof to be executed, or enables the method provided by the third aspect or any possible implementation thereof to be executed.

[0070] In a twelfth aspect, an embodiment of the present application provides a communication system, comprising a terminal device capable of implementing the method provided in the first aspect above, a first satellite capable of implementing the method provided in the second aspect above, and a second satellite capable of implementing the method provided in the third aspect above.

[0071] In the thirteenth aspect, an embodiment of the present application also provides a chip system, which includes a processor for supporting a terminal device to implement the functions involved in the first aspect above; or for supporting a first satellite to implement the functions involved in the second aspect above; or for supporting a second satellite to implement the functions involved in the third aspect above.

[0072] In a possible design, the chip system further includes a memory, and the memory is used to store necessary program instructions and data executed by the loading device. The chip system can be composed of a chip, or can include a chip and other discrete devices.

[0073] It should be noted that the technical effects that can be achieved by any possible implementation method of the above-mentioned fourth to thirteenth aspects or the fourth to thirteenth aspects can be correspondingly described with reference to the technical effects that can be achieved by any possible implementation method of the above-mentioned first to third aspects or the first to third aspects; they will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 A schematic diagram of a satellite mobile communication system to which the method of the embodiment of the present application can be applied;

[0075] Figure 2A A schematic diagram of a random access process;

[0076] Figure 2B is a schematic diagram of a time-advanced TA;

[0077] Figure 3A A flow chart of a communication method provided in an embodiment of the present application;

[0078] Figure 3B A flow chart of another communication method provided in an embodiment of the present application;

[0079] Figure 4A A specific flow chart of the first embodiment provided in the embodiments of the present application;

[0080] Figure 4B A schematic diagram of an implicit indication using RA-RNTI scrambling provided in an embodiment of the present application;

[0081] Figure 4C A schematic diagram of the structure of a RAR provided in an embodiment of the present application;

[0082] Figure 5A A specific flow chart of the second embodiment provided in the embodiments of the present application;

[0083] Figure 5B This is a schematic diagram of the structure of another RAR provided in an embodiment of the present application;

[0084] Figure 6 A specific flow chart of the third embodiment provided in the embodiments of the present application;

[0085] Figure 7 A specific flow chart of the fourth embodiment provided in the embodiments of the present application;

[0086] Fig. 8A A specific flow chart of the fifth embodiment provided in the embodiments of the present application;

[0087] Figure 8B This is a schematic diagram of the structure of another RAR provided in an embodiment of the present application;

[0088] Fig. 9A A specific flow chart of the sixth embodiment provided in the embodiments of the present application;

[0089] Fig. 9B This is a schematic diagram of the structure of another RAR provided in an embodiment of the present application;

[0090] Fig.10 A specific flow chart of the seventh embodiment provided in the embodiments of the present application;

[0091] Fig.11 A specific flow chart of the eighth embodiment provided in the embodiments of the present application;

[0092] Fig.12A schematic diagram of the structure of a communication device provided in an embodiment of the present application;

[0093] Fig.13 A schematic diagram of the structure of another communication device provided in an embodiment of the present application;

[0094] Fig.14 A schematic diagram of the structure of a chip provided in an embodiment of the present application. DETAILED DESCRIPTION

[0095] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present application. The terms used in the following embodiments are only for the purpose of describing specific embodiments and are not intended to be limiting of the present application.

[0096] As used in the specification and appended claims of the present application, the singular expressions "a", "an", "said", "above", "the" and "this" are intended to also include expressions such as "one or more", unless the context clearly indicates otherwise. It should also be understood that in the embodiments of the present application, "one or more" refers to one, two or more; "and / or" describes the association relationship of associated objects, indicating that three relationships may exist; for example, A and / or B may represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B may be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0097] References to "one embodiment" or "some embodiments" etc. described in this specification mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. The terms "include", "comprises", "has" and their variations all mean "including but not limited to", unless otherwise specifically emphasized. Words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions, and any embodiment or design described as "exemplary" or "for example" should not be interpreted as being more preferred or more advantageous than other embodiments or designs. The use of words such as "exemplary" or "for example" is intended to present related concepts in a concrete way for easy understanding.

[0098] And, unless otherwise stated, the ordinal numbers such as "first" and "second" mentioned in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the order, timing, priority or importance of multiple objects. In addition, the term "used to indicate" mentioned in the description of the embodiments of the present application may include being used for direct indication and being used for indirect indication. When describing that a certain indication information is used to indicate A, it may include that the indication information directly indicates A or indirectly indicates A, and it does not mean that the indication information must carry A. The terms "system" and "network" in the embodiments of the present application may be used interchangeably, and the terms "field" and "domain" may be used interchangeably.

[0099] In order to better understand the technical issues and communication methods raised in the embodiments of the present application, the relevant technologies involved in the present application are introduced below.

[0100] In satellite communications, due to the complex space environment, some scenarios are prone to occur, resulting in the source satellite accessed by the terminal device being unable to serve the terminal device. For example, 1) Scenario 1: The source satellite encounters a geosynchronous earth orbit (GEO) satellite and needs to avoid interference and shut down the beam; 2) Scenario 2: The source satellite moves to the Earth's polar region and needs to shut down the satellite, or shut down some of the beams in the satellite; 3) Scenario 3: Tracking, telemetry and command (TT&C) instructs the source satellite to adjust its attitude, change its working mode, etc. These will cause the source satellite to be unable to continue to provide services to the terminal device, so it is necessary to request access to a new satellite for the terminal device to achieve communication.

[0101] However, the current random access technology of the new radio (NR) is completed within a base station, and there is no random access process across base stations. Therefore, for the scenario where the source satellite can no longer serve the terminal device, how to achieve cross-satellite access for the terminal device is one of the problems that need to be solved urgently.

[0102] In view of the above problems, the present application provides a communication method, which can effectively realize inter-satellite access for terminal devices. The technical solution provided in the embodiment of the present application can be adapted to various non-terrestrial networks (non-terrestrialnetwork, NTN), and the non-terrestrial communication equipment (such as satellite) contained in the non-terrestrial network can communicate with the terrestrial equipment (such as terminal equipment) to provide wide-area coverage communication services for the terrestrial equipment. The non-terrestrial communication equipment in the embodiment of the present application may include but is not limited to satellites, which can be used as access points for terrestrial equipment, similar to base stations in terrestrial mobile communication systems, such as long-term evolution networks (long term evolution, LTE) / (base stations in fifth-generation wireless access networks-new radio (new radio, NR) and other networks. Satellites and terminal devices can communicate through wireless signals, and the communication protocol involved can be any one of the terrestrial mobile communication protocols and their variant protocols, which are not specifically limited in the present application.

[0103] Figure 1 FIG. 1 is a schematic diagram of the architecture of a satellite mobile communication system applicable to the embodiment of the present application. Figure 1 As shown, the satellite mobile communication system includes: 2 terminal devices (referred to as terminals), 2 satellite base stations (such as Figure 1 The satellite base station and the terminal device can communicate through the 5G new air interface. The two satellite base stations can communicate through the Xn interface. The satellite base station is connected to the ground station through the NG interface. The ground station is connected to the core network through the NG interface, which can be either wired or wireless. Satellites can usually form multiple beams, each of which is similar to a cell / sector in a terrestrial mobile communication system (such as LTE / NR).

[0104] 5G base station: mainly used to provide wireless access services, dispatch wireless resources to access terminal devices, provide reliable wireless transmission protocols and data encryption protocols, etc.

[0105] 5G core network: mainly used to provide user access control, mobility management, session management, user security authentication, billing and other functions. The core network consists of multiple functional units, which can be divided into control plane functional units and user plane processing units. Among them, the functional units of the control plane (or network elements) include access and mobility management function (AMF) and session management function network elements (SMF). AMF is responsible for user access management, security authentication, and mobility management. SMF is responsible for session management of terminal devices (including session establishment, modification and release), selection and reselection of user plane functional network elements, allocation of Internet Protocol (IP) addresses of terminal devices, quality of service (QoS) control, selection of UPF network elements that provide message forwarding functions, etc.

[0106] The user plane processing unit (or network element) includes a user plane function (UPF) unit. The UPF is responsible for managing the transmission of user plane data, traffic statistics and other functions.

[0107] Ground station: mainly responsible for forwarding signaling and business data between satellite and base station, or between satellite and core network.

[0108] 5G New Radio: refers to the wireless link between terminal devices and base stations.

[0109] Xn interface: represents the interface between 5G satellite base stations, mainly used for signaling interaction such as switching.

[0110] NG interface: refers to the interface between the 5G base station and the 5G core network, or the interface between the ground station and the core network, or the interface between the satellite base station and the ground station (in this case, the interface is a wireless link), which mainly interacts with the core network's non-access stratum (NAS) and other signaling, as well as user service data.

[0111] The above-mentioned ground station can be understood as a network device, such as an evolved node B (eNB), a radio network controller (RNC), a node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (for example, home evolved nodeB, or home node B, HNB), a baseband unit (BBU), an access point (AP) in a wireless fidelity (WIFI) system, a wireless relay node, a wireless backhaul node, a transmission point (TRP or transmission point, TP), etc. It can also be a gNB in ​​a 5G (such as NR) system, or a transmission point (TRP or TP), one or a group of (including multiple antenna panels) antenna panels of a base station in a 5G system, or it can also be a network node constituting a gNB or a transmission point, such as a baseband unit (BBU), a DU, a drone, etc.

[0112] In some deployments, the gNB may include a centralized unit (CU) and a DU. The gNB may also include a radio unit (RU). The CU implements some functions of the gNB, and the DU implements some functions of the gNB, for example, the CU implements the functions of the RRC and packet data convergence protocol (PDCP) layers, and the DU implements the functions of the radio link control (RLC), media access control (MAC) and physical (PHY) layers. Since the information of the RRC layer will eventually become the information of the PHY layer (i.e., sent through the PHY layer), or, converted from the information of the PHY layer, under this architecture, high-level signaling, such as RRC layer signaling or PDCP layer signaling, can also be considered to be sent by the DU, or, sent by the DU+RU. It can be understood that the access network device can be a CU node, or a DU node, or a device including a CU node and a DU node. In addition, the CU can be divided into a network device in the access network RAN, or the CU can be divided into a network device in the core network CN, which is not limited here.

[0113] The terminal device (terminal for short) involved in the embodiments of the present application is an entity on the user side for receiving or transmitting signals, and is used to send uplink signals to network devices, or receive downlink signals from network devices. It includes devices that provide voice and / or data connectivity to users, for example, it may include a handheld device with a wireless connection function, or a processing device connected to a wireless modem. The terminal device can communicate with the core network via a radio access network (RAN) and exchange voice and / or data with the RAN. The terminal device may include UE, V2X terminal device, wireless terminal device, mobile terminal device, device-to-device (D2D) terminal device, machine-to-machine / machine-type communications (M2M / MTC) terminal device, Internet of Things (IoT) terminal device, subscriber unit, subscriber station, mobile station, remote station, access point (AP), remote terminal, access terminal, user terminal, user agent, or user equipment, wearable device, vehicle-mounted device, drone, etc. In the embodiment of the present application, the terminal device can support the 5G new air interface, and can also access the satellite network through the air interface and initiate calls, Internet access and other services.

[0114] The various terminal devices introduced above, if located on a vehicle (eg, placed in or installed in a vehicle), can be considered as vehicle-mounted terminal devices, which are also called on-board units (OBU).

[0115] The above-mentioned satellites may be geostationary satellites, non-geostationary satellites, artificial satellites, low-orbit satellites, medium-orbit satellites, and high-orbit satellites, etc., which are not specifically limited in this application.

[0116] Above Figure 1 Just as an example, in practice Figure 1 The devices included in the satellite mobile communication system shown are not limited to satellites, terminal devices, ground stations and core networks, and the number of each device or network element therein is not limited.

[0117] The present application provides a communication method. In order to better understand the embodiments of the present application, the names and related technical features involved in the embodiments of the present application are explained below. It should be noted that these explanations are intended to make the embodiments of the present application easier to understand and should not be regarded as limiting the scope of protection claimed by the present application.

[0118] 1. Random access process:

[0119] The random access process refers to the process from when the terminal device sends a random access preamble to try to access the network to when it establishes a basic signaling connection with the network device (such as a base station). Random access is a very critical step in the mobile communication system and is also the last step in establishing a communication link between the terminal device and the network device. For example, the terminal device exchanges information with the network device through the random access process to complete subsequent operations, such as calling, resource request, or data transmission. In addition, the terminal device can also achieve uplink time synchronization with the system through random access.

[0120] The random access process can be divided into a contention-based random access process and a non-contention-based random access process. The embodiment of the present application is mainly described by taking the contention-based random access process as an example.

[0121] The contention-based random access process generally includes four steps, see Figure 2A As shown:

[0122] Step 201A: The terminal device sends a random access preamble to the network device, and the network device receives the random access preamble from the terminal device, wherein the random access preamble is also called the first message (MSG1) in the random access process.

[0123] Step 202A: The network device sends a random access response (RAR) message to the terminal device, and the terminal device receives the RAR message from the network device, wherein the RAR message is also called the second message (MSG2) in the random access process.

[0124] Step 203A: The terminal device sends an uplink signaling for establishing a radio resource control (RRC) connection to the network device, and the network device receives the uplink signaling from the terminal device.

[0125] Among them, the uplink signaling is also called the third message (MSG3) in the random access process. The uplink signaling can generally include an RRC signaling part and a media access control control element (MAC CE), etc. The RRC signaling may be different according to different scenarios, such as an RRC connection establishment request, an RRC re-establishment request, and an RRC recovery request.

[0126] Step 204A: The network device sends an RRC connection establishment message to the terminal device, and the terminal device receives the RRC connection establishment message from the network device, wherein the RRC connection establishment message is also called the fourth message (MSG4) in the random access process.

[0127] 2. Timing advance (TA):

[0128] TA refers to the offset of uplink transmission relative to downlink transmission, which can also be understood as the time between uplink radio frame i and the corresponding downlink radio frame i (N TA +N TA offset )×T s Seconds start, where N TA Refers to the timing advance control variable, and the specific value can be configured by the base station. TA offset is the offset of the timing advance control variable, T s Refers to the time unit, which can be 1 / (15000×2048) seconds, see Figure 2B The purpose of TA is to ensure that uplink signals sent by terminal devices at different distances from the base station can reach the base station at the same time.

[0129] Regarding the design of TA, after many discussions and analyses in standard meetings, the calculation of TA has gradually become the following formula 1:

[0130] T TA =(N TA +N TA，UE-specfic +N TA，common +N TA，offset )×T C ; Formula 1

[0131] The following is a detailed explanation of each parameter in formula 1.

[0132] N TA :(a) For a UE in RRC idle state and initiating a random access procedure, when sending a preamble, its uplink timing N TA =0, then N TA The value is carried by the random access response RAR in Msg2 / MsgB sent by the satellite, and its specific value is N TA =TA ·16·64 / 2 μ , where T A The value of T A =0, 1, 2, ..., 3846, μ represents the subcarrier spacing configuration parameter;

[0133] (b) For UE in RRC connected state, N TA The value of is updated by the satellite through MAC CE indication, and its update formula is N TA_new =N TA_old +(T A -31)·16·64 / 2 μ , where T A The value of T A =0, 1, 2, ..., 63, μ represents the subcarrier spacing configuration parameter.

[0134] N TA，UE-specfic : The UE calculates N based on the ephemeris information carried in the system message SIB sent by the satellite in the control beam and its own position information obtained based on GNSS. TA，UE-specific .

[0135] N TA，common : UE can obtain it by receiving the satellite broadcast signal.

[0136] N TA，offset : The UE determines the timing advance offset value N according to the n-TimingAdvanceOffset of the serving cell TA，offset If the UE is not provided with n-TimingAdvanceOffset, then for FR1 band, operating in FDD or TDD, non-E-UTRA-NR non-NB-IoT-NR coexistence scenario, N TA，offset =25600; for FR1 band, working in FDD, E-UTRA-NR and / or NB-IoT-NR coexistence scenario, N TA，offset = 0; for FR1 band, working in TDD, E-UTRA-NR and / or NB-IoT-NR coexistence scenario, N TA，offset =39936; for FR2 band, N TA，offset =13792, see prior art (Table 7.1.2-2 in TS38.133).

[0137] It should be noted that the terminal device in the embodiment of the present application needs to have GNSS capability, and the terminal device can also make timing advance according to the ephemeris and its own geographical location.

[0138] 3. Satellite ephemeris:

[0139] Satellite ephemeris is an important basic data source for the navigation system. It is a type of data that records the satellite's position, speed and time information (i.e., a set of data that can be used to describe the satellite's orbit). Through satellite ephemeris, the navigation system can calculate the receiver's position, speed, time and other information to achieve navigation. At the same time, satellite ephemeris can also be used in satellite orbit prediction, satellite control and other fields.

[0140] The technical solution of the present application is introduced below in conjunction with specific embodiments.

[0141] The present invention provides a communication method which is applicable to but not limited to Figure 1 The satellite mobile communication system shown. The method can be executed by the terminal device, the first satellite, and the second satellite; or the method can be executed by the components (modules, chips, etc.) in the terminal device, the first satellite, and the second satellite; or the method can be executed by a device corresponding to the terminal device, the first satellite, and the second satellite. The embodiments of the present application do not specifically limit the specific forms and corresponding quantities of the terminal device, the first satellite, and the second satellite. Please refer to Figure 3A As shown, the specific process of this method is as follows:

[0142] S301A: The terminal device sends first random access information to a first satellite, where the first random access information is used to request access to the first satellite. Correspondingly, the first satellite receives the first random access information from the terminal device.

[0143] S302A: The first satellite sends a first request message to the second satellite, where the first request message is used to request the terminal device to access the second satellite. Correspondingly, the second satellite receives the first request message from the first satellite.

[0144] If the first satellite determines that it cannot continue to serve the terminal device, the first request information may be sent to the second satellite.

[0145] In an embodiment of the present application, the above-mentioned first satellite can be regarded as a source satellite to be accessed by the terminal device (or a source satellite that has been accessed), and the second satellite can be regarded as a target satellite to be accessed by the terminal device. The first satellite and the second satellite are not the same satellite, and the types of the first satellite and the second satellite can be the same or different, and the present application is not limited to this. However, in some special cases or scenarios, the first satellite and the second satellite can also be the same satellite, then step S302A may not be executed, but the following S303A may be directly executed after S301A is executed.

[0146] S303A: The second satellite sends first response information to the first satellite. Correspondingly, the first satellite receives the first response information from the second satellite.

[0147] If the second satellite allows the terminal device to access, the second satellite may send the first response information to the first satellite, so that the first satellite confirms that the second satellite allows the terminal device to access, and then the first satellite may send the first indication information to the terminal device.

[0148] S304A: The first satellite sends first indication information to the terminal device, where the first indication information is used to instruct the terminal device to access the second satellite. Correspondingly, the terminal device receives the first indication information from the first satellite.

[0149] In the embodiment of the present application, the first satellite side may design the first indication information in the following but not limited to the following manner, so that the first indication information is effectively used to instruct the terminal device to access the second satellite:

[0150] Method 1: The first indication information is scrambled downlink control information; the scrambled downlink control information is obtained by scrambling the first downlink control information according to the random access radio network temporary identifier RA-RNTI of the first satellite, and the first bit information newly added in the first downlink control information is used to indicate the identification information of the second satellite; or, the scrambled downlink control information is obtained by scrambling the downlink control information according to the RA-RNTI of the first satellite and the identification information of the second satellite.

[0151] Method 2: The first indication information is the first random access response information used to respond to the first random access information; the reserved bit information in the first random access response information is used to indicate that the first random access response information is a random access response information for inter-satellite access, and the timing advance information field in the first random access response information is used to indicate the identification information of the second satellite.

[0152] Method three: the first indication information is a first random access response information used to respond to the first random access information; the temporary cell TC-RNTI information field in the first random access response information is used to indicate the identification information of the second satellite; or a second bit information is added to the first random access response information to indicate the identification information of the second satellite.

[0153] In the embodiment of the present application, after the above step S304A, the terminal device may also calculate the target TA of the second satellite, and access the second satellite based on the target TA of the second satellite.

[0154] The terminal device calculates the target TA of the second satellite, which may include but is not limited to the following implementations:

[0155] Implementation method 1: first obtain the public TA of the second satellite; and obtain the downlink timing of the first satellite and the downlink timing of the second satellite; and then determine the target TA of the second satellite according to the public TA of the second satellite, the downlink timing of the first satellite and the downlink timing of the second satellite. Optionally, this implementation method 1 can be applied to the above-mentioned method 1 and / or method 2.

[0156] In a possible implementation manner, the target TA of the second satellite may satisfy the following formula 1:

[0157] T TA =(N TA,UE-specfic +N TA,common +N TA,offset )×T C +2×(DL1-DL2); Formula 1

[0158] Among them, T TA represents the target TA of the second satellite, N TA,UE-specfic represents the TA of the first satellite, where the TA of the first satellite is determined according to the ephemeris information of the first satellite and the location information of the terminal device; N TA,common represents the common TA of the second satellite, N TA,offset Indicates the preset offset, T C is the minimum time unit, DL1 is the downlink timing of the first satellite, and DL2 is the downlink timing of the second satellite.

[0159] In a possible implementation, the terminal device may respectively receive the synchronization signal of the first satellite and the synchronization signal of the second satellite, the synchronization signal of the first satellite carries the downlink timing of the first satellite, and the synchronization signal of the second satellite carries the downlink timing of the second satellite, thereby achieving the purpose of obtaining the downlink timing of the first satellite and the downlink timing of the second satellite.

[0160] Implementation method 2: If the first random response information received by the terminal device also includes the first TA of the second satellite, the first TA of the second satellite is equal to the TA of the first satellite, or the first TA of the second satellite is determined according to the TA of the first satellite and the timing difference between the first satellite and the second satellite; then the terminal device can calculate the target TA of the second satellite through the following steps:

[0161] First, the public TA of the second satellite is obtained; and then, the target TA of the second satellite is obtained according to the first TA of the second satellite and the public TA of the second satellite. Optionally, the second implementation mode may be applicable to the third implementation mode described above.

[0162] In a possible implementation manner, the target TA of the second satellite may satisfy the following formula 2:

[0163] T TA =(N TA,UE-specfic +N TA +N TA,common +N TA,offset )×T C ; Formula 2

[0164] T TA represents the target TA of the second satellite; N TA,UE-specfic represents a second TA of the second satellite, where the second TA of the second satellite is determined according to the ephemeris information of the second satellite and the location information of the terminal device; N TA represents the first TA of the second satellite; N TA,common N represents the common TA of the second satellite; TA,offset Indicates the preset offset, T C The minimum time unit.

[0165] In a possible implementation, the terminal device may receive a broadcast signal from the second satellite, where the broadcast signal from the second satellite carries the public TA of the second satellite, so as to parse out the public TA of the second satellite from the received broadcast signal.

[0166] The present application embodiment provides another communication method, which is applicable to but not limited to Figure 1 The specific form of the execution subject of this method can refer to the above Figure 3A The form of the execution body of the scheme. Figure 3A Compared with the above scheme, the difference of this scheme is that: when the first satellite can no longer serve the terminal device, the terminal device requests to access the second satellite, the second satellite directly sends the first indication information to the terminal device to instruct the terminal device to access the second satellite, and the second satellite directly sends the information for accessing the second satellite to the terminal device. Figure 3B As shown, the specific process of this method is as follows:

[0167] S301B: same Figure 3A Step S301A in .

[0168] S302B: Same Figure 3A Step S302A in .

[0169] S303B: The second satellite sends first indication information to the terminal device, where the first indication information is used to instruct the terminal device to access the second satellite. Correspondingly, the terminal device receives the first indication information from the second satellite.

[0170] If the second satellite allows the terminal device to access, the first indication information will be sent to the terminal device.

[0171] In the embodiment of the present application, the manner in which the second satellite side designs the first indication information to instruct the terminal device to access the second satellite can specifically refer to the several manners in which the first satellite side designs the first indication information in the above step S304A, that is, the above Figure 3A The following methods, such as method 1, method 2 and method 3, are described in detail in S304A.

[0172] In the embodiment of the present application, after the above step S303B, the terminal device may further calculate the target TA of the second satellite, and access the second satellite based on the target TA of the second satellite. The terminal device calculates the target TA of the second satellite, and specifically refers to the several implementation modes described in the above step S304A, that is, implementation modes 1 and 2 in the above description, which will not be described in detail here.

[0173] based on Figure 3A The scheme and the above Figure 3B It can be seen from the scheme that in the embodiment of the present application, when the first satellite is unable to continue to serve the terminal device, after the terminal device requests access to the second satellite, the first satellite can be selected to transmit the first indication information and / or the information required for accessing the second satellite to the terminal device, or the second satellite can be selected to directly transmit the first indication information and / or the information required for accessing the second satellite to the terminal device. In addition, the transmission path of the first indication information and / or the information required for accessing the second satellite is not limited in the embodiment of the present application, and the first indication information and / or the information required for accessing the second satellite can also be flexibly transmitted to the terminal device through other transmission paths.

[0174] To sum up, in a scenario where the source satellite can no longer serve the terminal device, the embodiments of the present application can effectively provide the terminal device with access to other available satellites (i.e., achieve inter-satellite access for the terminal device) to ensure normal communication between the terminal device and the satellite.

[0175] Based on the above Figure 3A and Figure 3B The communication method is further described in detail below through several specific embodiments.

[0176] Embodiment 1:

[0177] Based on the above Figure 3A In the solution, in the first embodiment, UE1 is used as an example of a terminal device for inter-satellite access. UE1 requests to access the source satellite (equivalent to the above Figure 3A The first satellite in the solution), when the source satellite cannot continue to serve the UE1, requests the UE1 to access the target satellite that can serve the UE1 (equivalent to the above Figure 3A The second satellite in the scheme); and the source satellite sends a scrambled DCI to the UE1 (equivalent to the above Figure 3A The first indication information in the solution) is used to instruct the UE1 to access the target satellite across satellites. Figure 4A As shown, the process of this embodiment 1 is specifically as follows:

[0178] S401A: The source satellite sends a synchronization signal 1 to UE1. Correspondingly, UE1 receives the synchronization signal 1. The synchronization signal 1 carries the downlink timing DL1 of the source satellite.

[0179] S402A: The target satellite sends a synchronization signal 2 to UE1. Correspondingly, UE1 receives the synchronization signal 2. The synchronization signal 2 carries the downlink timing DL2 of the target satellite.

[0180] The embodiment of the present application does not specifically limit the time sequence of executing the above steps S401A and S402A. In the above steps S401A and S402A, UE1 can achieve signal synchronization with the source satellite and the target satellite respectively.

[0181] S403A: UE1 sends random access information to the source satellite. Correspondingly, the source satellite receives the random access information from UE1 (equivalent to the above Figure 3A The first random access information in the scheme).

[0182] Exemplarily, UE1 selects satellite 1 (i.e., source satellite) for access and sends Msg1 to satellite 1. Due to the low link budget of NTN, the total time for NB-IoT to send the preamble is relatively long, and multiple attempts are required before satellite 1 finally detects Msg1.

[0183] S404A: The source satellite determines that it cannot continue to serve the UE1.

[0184] In an embodiment of the present application, the reasons why the source satellite cannot continue to serve the UE1 may include but are not limited to: the remaining visible time of the source satellite covering UE1 is less than the handshake time of the random access channel (RACH) of 4 steps between UE1 and the source satellite, the source satellite changes its working mode, and the source satellite encounters a GEO satellite and needs to shut down its beam.

[0185] S405A: The source satellite sends a first request message to the target satellite, where the first request message is used to request the UE1 to access the target satellite.

[0186] In a possible implementation manner, the source satellite may attempt to send a first request message to at least one target satellite, where the first request message is used to request UE1 to access the corresponding target satellite.

[0187] S406A: The target satellite sends the first response information to the source satellite.

[0188] In one implementation, the first response information is used to indicate to the source satellite whether the target satellite allows UE1 to access. If the target satellite allows UE1 to access, the first response information can be used to indicate to the source satellite that the target satellite allows UE1 to access. The first response information can carry: a downlink grant (UL Grant) allocated by the target satellite to UE1, a temporary cell-radionetwork temporary indentifier (TC-RNTI) allocated by the target satellite to UE1, and a backoff indicator (BI).

[0189] In another implementation, the first response information is used to instruct the source satellite to send a scrambled DCI to UE1, and the scrambled DCI is used to instruct UE1 to access the target satellite.

[0190] S407A: The source satellite sends a scrambled DCI to UE1, and the scrambled DCI is used to instruct UE1 to access the target satellite. Correspondingly, UE1 receives the scrambled DCI from the source satellite (the scrambled DCI is equivalent to the above Figure 3A The first indication information in the scheme).

[0191] In this embodiment, the source satellite may use its own random access radio network temporary identifier (ie, RA-RNTI) to scramble DCI1_0, and the scrambling methods may include the following:

[0192] Display method: add n bits of information to DCI1_0, where the n bits of information are used to indicate the ID of the target satellite, where n is an integer greater than 0; then use the RA-RNTI of the source satellite to scramble the DCI1_0 with the newly added n bits of information to obtain the scrambled DCI1_0.

[0193] Implicit method: DCI1_0 is scrambled using the RA-RNTI of the source satellite and the ID of the target satellite to obtain scrambled DCI1_0.

[0194] For example, DCI1_0 is scrambled using RA-RNTI+ξ (symbol ξ represents the offset of RA-RNTI), where the value of ξ corresponds to the ID of the target satellite. If k=2bit information is used to represent the ID of the target satellite, the set of target satellite IDs is {#501, #502, #503, #504}, and the value of ξ corresponding to the set of target satellite IDs is {0, 1, 2, 3}, the target satellite ID is #501, the corresponding ξ value is 0, the target satellite ID is #502, the corresponding ξ value is 1, the target satellite ID is #503, the corresponding ξ value is 2, and the target satellite ID is #504, the corresponding ξ value is 3.

[0195] After receiving the scrambled DCI1_0, if UE1 successfully descrambles the scrambled DCI1_0 using RA-RNTI+2, it can be known that ξ=2; further, UE1 determines that the ID of the target satellite is #503 based on ξ=2 and the correspondence between the value of ξ and the ID of the target satellite.

[0196] Figure 4B A schematic diagram showing a method of scrambling CRC (equivalent to DCI1_0) using RA-RNTI+ξ (equivalent to the RA-RNTI of the source satellite and the ID of the target satellite) is shown. Figure 4B As shown, the RA-RNTI is first offset according to the offset ξ, and then the CRC is scrambled using the offset-processed RA-RNTI (ie, RA-RNTI+ξ).

[0197] S408A: The source satellite sends a random access response RAR to UE1. Correspondingly, UE1 receives the random access response RAR from the source satellite.

[0198] In one implementation, the random access response RAR may carry: a downlink grant (UL Grant) allocated by the target satellite to UE1, a TC-RNTI allocated by the target satellite to UE1, a BI, and a random access preamble identifier (RAPID).

[0199] For example, Figure 4C The structure of a RAR is shown, in which the Timing Advance information field is invalid. For example, the format of the RAR is not changed, and the value in the Timing Advance is set to empty or randomly assigned.

[0200] S409A: UE1 calculates the TA of the target satellite.

[0201] Before calculating the TA of the target satellite, UE1 first calculates the following information:

[0202] (1): Determine the time difference (DL1-DL2) between the downlink signals of the source satellite and the target satellite.

[0203] In the above steps S401A and S402A, UE1 receives the synchronization signal 1 of the source satellite and the synchronization signal 2 of the target satellite, and can obtain the downlink timing DL1 of the source satellite from the synchronization signal 1, and the downlink timing DL2 of the target satellite from the synchronization signal 2; further, UE1 calculates the time difference between the downlink signals of the source satellite and the target satellite according to the downlink timing DL1 of the source satellite and the downlink timing DL2 of the target satellite, which is: DL1-DL2.

[0204] (2): UE1 uses the time symmetry of the uplink and downlink air interfaces and obtains the time difference of the uplink signal UE-specific TA according to the time difference of the downlink signals of the source satellite and the target satellite: 2×(DL1-DL2).

[0205] In the above, the time difference of the uplink signal UE-specific TA is equivalent to the sum of the difference between the TA of the source satellite and the UE-specific TA of the two satellites. TA,UE-specfic(源卫星) +N 两卫星的偏移差值 .

[0206] Among them, N 两卫星的偏移差值 It is expressed as the difference between the UE-specific TA of the source satellite and the UE-specific TA of the target satellite, such as N 两卫星的偏移差值 =|N TA,UE-specfic(源卫星) -N TA,UE-specfic(目标卫星) |, || are absolute value symbols.

[0207] (3): UE1 determines the TA of the source satellite, that is, N in the following formula 1-2 TA,UE-specfic(源卫星) .

[0208] For example, the system message SIB sent by the source satellite carries the ephemeris information of the source satellite. Then, UE1 can obtain the ephemeris information of the source satellite by receiving the system message SIB sent by the source satellite; and UE1 can obtain its own geographical location information based on GNSS; further, UE1 calculates the TA of the source satellite based on the ephemeris information of the source satellite and its own geographical location information. For example, N in the following formula 1-2 is TA,UE-specfic(源卫星) .

[0209] (4): UE1 obtains the public TA of the target satellite.

[0210] For example, the target satellite may carry its own public TA in the broadcast signal, and then UE1 may obtain the public TA of the target satellite by receiving the broadcast signal of the target satellite, that is, N in the following formula 1-2: TA,common(目标卫星) .

[0211] The following formula 1-1 is an existing formula for calculating the TA of a target satellite.

[0212] T TA(目标卫星) =(N TA(目标卫星) +N TA,UE-specfic(源卫星) +N TA,common(目标卫星) +N TA,offset )×T C ; Formula 1-1

[0213] Among them, N TA(目标卫星) ×T C =(N TA,UE-specfic(源卫星) +N 两卫星的偏移差值 )×T C =2×(DL1-DL2);

[0214] The above formula 1-1 can be converted into the following formula 1-2 (the formula 1-2 is equivalent to the above formula Figure 3A Formula 1 in the scheme):

[0215] T TA(目标卫星) =(N TA,UE-specfic(源卫星) +N TA,common(目标卫星) +N TA,offset )×T C +2×(DL1-DL2); Formula 1-2

[0216] Based on the several information values ​​calculated above, UE1 can calculate the timing advance value T of the target satellite through the above formula 1-2. TA(目标卫星) .

[0217] In the above formula 1-2, T C In the embodiment of the present application, N is a time unit known to UE1. TA,offset It can be determined by UE1 based on the n-TimingAdvanceOffset of the serving cell. If UE1 is not provided with n-TimingAdvanceOffset, then N TA,offset is a preset known value (refer to the prior art, for FR1 band, working in FDD or TDD, non-E-UTRA-NR non-NB-IoT-NR coexistence scenario, N TA,offset =25600; for FR1 band, working in FDD, E-UTRA-NR and / or NB-IoT-NR coexistence scenario, N TA,offset= 0; for FR1 band, working in TDD, E-UTRA-NR and / or NB-IoT-NR coexistence scenario, N TA,offset =39936; for FR2 band, N TA,offset =13792).

[0218] In the present embodiment, T C is a time unit, and the source satellite, target satellite, and UE (including UE1) all know T C The source satellite can enable UE1 to obtain the N value of the source satellite through the above steps. TA,UE-specfic(源卫星) and the target satellite common N TA,common(目标卫星) , so that UE1 can C , calculate the corresponding source satellite T TA,UE-specfic(源卫星) and the target satellite's common T TA,common(目标卫星) In addition, the source satellite can also enable UE1 to directly obtain the T of the source satellite through the above steps. TA,UE-specfi(c源卫星) and the target satellite's common T TA,common(目标卫星) In this regard, the embodiments of the present application do not make any specific limitation.

[0219] S410A: UE1 accesses the target satellite.

[0220] In one implementation, UE1 may access the target satellite based on the obtained downlink grant (UL Grant) allocated by the target satellite, TC-RNTI, BI, random access preamble identifier (RAPID), and TA of the target satellite. The specific process of UE1 accessing the target satellite may be implemented by referring to the access process of the prior art, and will not be described in detail here.

[0221] In this embodiment 1, taking UE1 as an example, UE1 requests to access the source satellite. If the source satellite determines that it cannot continue to serve UE1, it can request UE1 to access other available target satellites. If the target satellite allows UE1 to access, the source satellite can send an encrypted DCI to UE1 to instruct UE1 to access the target satellite. After UE1 identifies itself as an inter-satellite UE, it can calculate the TA of the target satellite through the downlink delay difference, and thus can effectively complete the subsequent inter-satellite access process.

[0222] Embodiment 2:

[0223] Based on the above Figure 3A The scheme, compared with the above embodiment 1, the main difference of the second embodiment is that after the source satellite requests the UE1 to access the target satellite that can serve the UE1, the source satellite sends a random access response RAR (equivalent to the above embodiment 1) to the UE1. Figure 3AThe first indication information in the solution) is used to instruct the UE1 to access the target satellite across satellites. Figure 5A As shown, the specific process of the second embodiment is as follows:

[0224] Please refer to the specific implementation process of S501A to S506A one by one. Figure 4A The specific implementation process of S401A to S406A will not be described in detail again.

[0225] S507A: The source satellite sends the scrambled DCI to UE1. Correspondingly, UE1 receives the scrambled DCI from the source satellite.

[0226] In S507, the source satellite does not change any format of the DCI, and uses its own RA-RNTI to scramble the DCI to obtain a scrambled DCI.

[0227] S508A: The source satellite sends a random access response RAR to UE1, where the RAR is used to instruct UE1 to access the target satellite.

[0228] Correspondingly, UE1 receives the random access response RAR (equivalent to the above Figure 3A The first indication information in the scheme).

[0229] For example, Figure 5B Another RAR structure is shown, which includes the random access preamble identifier RAPID, the UL-GRANT and TC-RNTI allocated by the target satellite, and the BI. The R field in the RAR indicates a reserved bit. The RAR sent by the source satellite can be designed in the following way to indicate the ID of the target satellite:

[0230] 1. From the R field (reserved bit), select one bit to indicate the type of the RAR.

[0231] For example, if the bit is set to 0, it indicates that the RAR is a RAR in a common format; if the bit is set to 1, it indicates that the RAR is a RAR for inter-satellite access.

[0232] 2. When the Timing Advance information field is invalid, the Timing Advance information field in the RAR can be used to indicate the ID of the target satellite.

[0233] If the RAR sent by the source satellite received by UE1 is a normal format RAR, then UE1 can normally interpret the Timing Advance information field. If the RAR sent by the source satellite received by UE1 is an inter-satellite access RAR, then UE1 obtains the ID of the target satellite by interpreting the Timing Advance information field.

[0234] In addition, the T field in the RAR is a type field, which is usually used to indicate whether the MAC subheader includes RAPID or BI.

[0235] The embodiment of the present application does not specifically limit how to reuse the Timing Advance information field in the RAR to indicate the ID of the target satellite. For example, a correspondence between multiple values ​​of the Timing Advance information field and multiple target satellite IDs is preset, so that UE1 can determine the ID of the corresponding target satellite by interpreting the value of the Timing Advance information field in the RAR.

[0236] Next, please refer to the specific implementation process of S509 to S510A Figure 4A The specific implementation process of S409A to S410A will not be described in detail again.

[0237] In the second embodiment, taking UE1 as an example, UE1 requests to access the source satellite. If the source satellite determines that it cannot continue to serve UE1, it can request UE1 to access other available target satellites, and if the target satellite allows UE1 to access, the source satellite can send a random access response RAR to UE1 to instruct UE1 to access the target satellite; after UE1 identifies itself as an inter-satellite UE, it can calculate the TA of the target satellite through the downlink delay difference, and thus can effectively complete the subsequent inter-satellite access process.

[0238] Embodiment three:

[0239] Compared with the above embodiment 1, the difference of the embodiment 3 is that: based on the above Figure 3B In the solution, after the source satellite requests UE1 to access the target satellite that can serve UE1, the target satellite directly sends the scrambled DCI to UE1 (equivalent to the above Figure 3B The first indication information in the solution) is used to instruct the UE1 to access the target satellite across satellites. Figure 6 As shown, the specific process of this embodiment three is as follows:

[0240] Please refer to the specific implementation process of S601 to S604 one by one. Figure 4A The specific implementation process of S401A to S404A will not be described in detail again.

[0241] S605: The source satellite sends a first request message to the target satellite, the first request message is used to request the UE1 to access the target satellite. The first request message carries the RA-RNTI and random preamble identifier RAPID of the source satellite.

[0242] In an embodiment of the present application, the source satellite may also carry the RA-RNTI and random preamble identifier RAPID of the source satellite in different messages and send them to UE1, or send the RA-RNTI and random preamble identifier (RAPID) of the source satellite as independent messages to UE1. The present application does not make specific limitations on this.

[0243] S606: The target satellite sends a scrambled DCI to UE1, and the scrambled DCI is used to instruct UE1 to access the target satellite. Correspondingly, UE1 receives the scrambled DCI from the target satellite (equivalent to the above Figure 3B The first indication information in the scheme).

[0244] Exemplarily, the target satellite can use the RA-RNTI of the source satellite to scramble DCI1_0; the specific way in which the target satellite uses the RA-RNTI of the source satellite to scramble DCI1_0 can be implemented by referring to the several ways (such as explicit way and implicit way) in which the source satellite uses its own RA-RNTI to scramble DCI1_0 in S407A above, which will not be described in detail here.

[0245] S607: The target satellite sends a random access response RAR to UE1. Correspondingly, UE1 receives the random access response RAR from the target satellite. The random access response RAR carries the RAPID from the source satellite, the UL-GRANT and TC-RNTI, and BI allocated by the target satellite to UE1.

[0246] For example, the structure of the RAR designed for the target satellite may specifically refer to the structure of the RAR designed for the source satellite in S408A (eg Figure 4C Detailed description is not given here.

[0247] Next, please refer to the specific implementation process of S608 to S609 one by one. Figure 4A The specific implementation process of S409A to S410A will not be described in detail again.

[0248] In the third embodiment, taking UE1 as an example, UE1 requests to access the source satellite. If the source satellite determines that it can no longer serve UE1, it can request UE1 to access the target satellite that can serve UE1. If the target satellite allows UE1 to access, it can directly send an encrypted DCI to UE1 to instruct UE1 to access the target satellite. After UE1 identifies itself as an inter-satellite UE, it can calculate the TA of the target satellite through the downlink delay difference, and thus effectively complete the subsequent inter-satellite access process.

[0249] Embodiment 4:

[0250] Compared with the above-mentioned embodiment 2, the difference of the embodiment 4 is that: based on the above-mentioned Figure 3B In the solution, after the source satellite requests UE1 to access the target satellite that can serve UE1, the target satellite directly sends a random access response RAR to UE1 (equivalent to the above Figure 3B The first indication information in the solution) is used to instruct the UE1 to access the target satellite across satellites. Compared with the above-mentioned embodiment 3, the main difference of the embodiment 4 is that: the target satellite directly sends the RAR to the UE1 to instruct the UE1 to access the target satellite across satellites. Figure 7 As shown, the specific process of the fourth embodiment is as follows:

[0251] Please refer to the specific implementation process of S701 to S704 one by one. Figure 5A S501A to S504A (or Figure 4A The specific implementation process of S401A to S404A) will not be described in detail again.

[0252] For the specific implementation process of S705, please refer to Figure 6 The specific implementation process of S605 will not be described in detail.

[0253] S706: The target satellite sends the scrambled DCI to UE1. Correspondingly, UE1 receives the scrambled DCI from the target satellite (the format of the DCI is not changed).

[0254] The target satellite may use the RA-RNTI of the source satellite to scramble the DCI to obtain the scrambled DCI (without changing the format of the DCI or the scrambled DCI).

[0255] S707: The target satellite sends a random access response RAR to UE1, where the RAR is used to instruct UE1 to access the target satellite.

[0256] The RAR carries the random access preamble identifier RAPID from the source satellite, the UL-GRANT and TC-RNTI, and BI allocated by the target satellite to UE1.

[0257] For example, the structure of the RAR sent by the target satellite can be seen in the above Figure 5B As shown, the target satellite designs RAR to indicate the ID of the target satellite. For details, reference can be made to the method in which the source satellite designs RAR to indicate the ID of the target satellite in step S508A above, which will not be repeated here.

[0258] Next, please refer to the specific implementation process of S708 and S709 one by one. Figure 5A S509A and S510A (or Figure 4A S409A and S410A), which will not be described in detail.

[0259] In the fourth embodiment, taking UE1 as an example, UE1 requests to access the source satellite. If the source satellite determines that it can no longer serve UE1, it can request UE1 to access the target satellite that can serve UE1. If the target satellite allows UE1 to access, it can directly send a random access response RAR to UE1 to instruct UE1 to access the target satellite. After identifying itself as an inter-satellite UE, UE1 can calculate the TA of the target satellite through the downlink delay difference, and thus can effectively complete the subsequent inter-satellite access process.

[0260] The above-mentioned embodiments 1 to 4 correspond to the implementation method 1 in which the terminal device calculates the target TA of the second satellite in the above-mentioned step S304A (or S303B) to calculate the TA of the target satellite, and the following embodiments 5 to 8 correspond to the implementation method 2 in which the terminal device calculates the target TA of the second satellite in the above-mentioned step S304A (or S303B) to calculate the TA of the target satellite.

[0261] Embodiment five:

[0262] Based on the above Figure 3A Compared with the above-mentioned embodiment 1, the difference of the above-mentioned embodiment 5 is that the method in which UE1 calculates the TA of the target satellite is different (that is, the second implementation method in which the terminal device calculates the target TA of the second satellite in the above-mentioned step S304A is adopted). Fig. 8A As shown, the specific process of the fifth embodiment is as follows:

[0263] Please refer to the specific implementation process of S801A to S805A one by one. Figure 4A The specific implementation process of S401A to S405A will not be described in detail again.

[0264] S806A: The target satellite sends the first response information to the source satellite. Correspondingly, the source satellite receives the first response information from the target satellite.

[0265] The S806A can refer to the above Figure 4A Optionally, different from S406A, the first response information in S806A also carries the timing difference (or timing offset) between the source satellite and the target satellite.

[0266] In an embodiment of the present application, the timing difference (or timing offset value) between the source satellite and the target satellite may also be carried in other information to be sent to the source satellite, or may be sent to the source satellite as independent information; the present application does not specifically limit the manner and means by which the target satellite sends the timing difference (or timing offset value) between the source satellite and the target satellite to the source satellite.

[0267] For the specific implementation process of S807A, please refer to Figure 4A The specific implementation process of S407A will not be described in detail.

[0268] S808A: The source satellite sends a random access response RAR to UE1. Correspondingly, UE1 receives the random access response RAR from the source satellite.

[0269] The S808A can refer to the above Figure 4A S408A, different from the above Figure 4A The random access response RAR in S408A and S808A also carries the first TA value of the target satellite.

[0270] For example, Figure 8B A schematic diagram of the structure of another RAR is shown, in which the timing advance (Timing Advance) information field is valid and the timing advance (Timing Advance) information field can be reused to indicate (or represent) the first TA of the target satellite.

[0271] In the fifth embodiment, the “first TA of the target satellite” is used to distinguish it from the “TA of the target satellite” determined by UE1 described below.

[0272] In one implementation, the source satellite determines the first TA of the target satellite, including: the source satellite first obtains its own geographic location information based on GNSS; then calculates its own TA based on its own ephemeris information and its own geographic location information; finally, the source satellite calculates the first TA of the target satellite based on its own TA and the timing difference (or timing offset) between the source satellite and the target satellite. As shown in the following formula 1-1, N TA(目标卫星) .

[0273] S809A: UE1 calculates the TA of the target satellite.

[0274] UE1 can directly use the above formula 1-1 (equivalent to the above formula Figure 3A The TA of the target satellite is calculated using formula 2 in .

[0275] T TA(目标卫星) =(N TA(目标卫星) +N TA,UE-specfic(源卫星) +N TA,common(目标卫星) +N TA,offset )×T C ; Formula 1-1

[0276] Among them, N TA(目标卫星) It is the first TA sent by the source satellite to the target satellite of UE1 in the above step S808A. TA,UE-specfic(源卫星)It can be calculated by UE1 based on the ephemeris information of the source satellite (the ephemeris information of the source satellite can be obtained through the system message of the source satellite) and the geographic satellite information of UE1 itself; N TA,common(目标卫星) It can be obtained by UE1 by receiving the target satellite broadcast signal.

[0277] In the above formula 1-1, T C In the embodiment of the present application, N is a time unit known to UE1. TA,offset It can be determined by UE1 based on the n-TimingAdvanceOffset of the serving cell. If UE1 is not provided with n-TimingAdvanceOffset, then N TA,offset is a preset known value (refer to the prior art, for FR1 band, working in FDD or TDD, non-E-UTRA-NR non-NB-IoT-NR coexistence scenario, N TA,offset =25600; for FR1 band, working in FDD, E-UTRA-NR and / or NB-IoT-NR coexistence scenario, N TA,offset = 0; for FR1 band, working in TDD, E-UTRA-NR and / or NB-IoT-NR coexistence scenario, N TA,offset =39936; for FR2 band, N TA,offset =13792).

[0278] In the present embodiment, T C is a time unit, and the source satellite, target satellite, and UE1 all know T C The source satellite can provide (send) the N value of the target satellite to UE1 through the above steps. TA(目标卫星) , the common N of the target satellite TA,common(目标卫星) , so that UE1 can C , calculate the T of the corresponding target satellite TA(目标卫星) and the target satellite's common T TA,comm(on目标卫星) In addition, the source satellite can also directly provide (send) the T of the target satellite to UE1 through the above steps. TA(目标卫星) and the target satellite's common T TA,common(目标卫星) In this regard, the embodiments of the present application do not make any specific limitation.

[0279] Next, please refer to the specific implementation process of step S810A. Figure 4A The specific implementation process of S410A will not be described in detail.

[0280] In the fifth embodiment, taking UE1 as an example, UE1 requests to access the source satellite. If the source satellite determines that it cannot continue to serve UE1, it can request UE1 to access other available target satellites, and if the target satellite allows UE1 to access, the source satellite can send an encrypted DCI to UE1 to instruct UE1 to access the target satellite; and also provide (or send) parameters in the existing calculation formula (such as the first TA of the target satellite determined by the source satellite) to UE1 through the source satellite; so that after UE1 identifies itself as an inter-satellite UE, it can directly calculate the TA of the target satellite through the existing calculation formula, and thus can effectively complete the subsequent inter-satellite access process.

[0281] Embodiment six:

[0282] Compared with the above-mentioned embodiment 5, the main difference of the embodiment 6 is that after the source satellite requests UE1 to access the target satellite, the source satellite sends a random access response RAR (equivalent to the above-mentioned Figure 3A The first indication information in the solution) is used to instruct the UE1 to access the target satellite across satellites. Fig. 9A As shown, the specific process of the sixth embodiment is as follows:

[0283] Please refer to the specific implementation process of S901A to S905A one by one. Fig. 8A S801A to S805A (or Figure 4A The specific implementation process of S401A to S405A) will not be described in detail again.

[0284] For the specific implementation process of S906A, please refer to Fig. 8A The specific implementation process of S806A will not be described in detail.

[0285] For the specific implementation process of S907A, please refer to Figure 5A The specific implementation process of S507A (ie, the source satellite can use RA-RNTI to scramble DCI and send the scrambled DCI to UE1 without changing DCI) will not be described in detail again.

[0286] S908A: The source satellite sends a random access response RAR to UE1, and the RAR is used to instruct UE1 to access the target satellite. Correspondingly, UE1 receives the random access response RAR from the source satellite (equivalent to the above Figure 3A The first indication information in the scheme).

[0287] The specific implementation process of S908A can refer to Fig. 8AThe specific implementation process of S808A in FIG. 1 is different from that of S808A. S908A designs RAR to indicate the ID of the target satellite and the first TA of the target satellite in the following manner:

[0288] like Fig. 9B As shown, the RAR includes the random access preamble identifier RAPID, the UL-GRANT, TC-RNTI, and BI assigned by the target satellite; the timing advance information field is used to indicate the first TA of the target satellite; in the RAR, the R field corresponds to the reserved bit, and 1 bit can be selected from it to indicate the type of RAR. For example, if the 1 bit is set to 0, it means that the RAR is a normal format RAR; if the 1 bit is set to 1, it means that the RAR is an inter-satellite access RAR. The RAR is designed in the following way to indicate the ID of the target satellite:

[0289] Method 1: Add n bits (n is an integer greater than 0) in the RAR, and the n bits are used to indicate the ID of the target satellite.

[0290] Method 2: reuse the Temporary C-RNTI information field in the RAR to indicate the ID of the target satellite.

[0291] Specifically, the target satellite ID can be implicitly indicated based on the TC-RNTI division method; if the TC-RNTI is 16 bits in total, 0x0001 to 0xFFEF (such as 1 to 65519); the lower m bits of the TC-RNTI are reused to represent the target satellite ID, where m is an integer greater than 0. For example, the lower 3 bits of the TC-RNTI are used to represent the IDs of 8 satellites.

[0292] In an embodiment of the present application, the first TA of the target satellite may also be carried in other messages and sent to UE1, or sent to UE1 as an independent message, and the present application does not make any specific limitation on this.

[0293] Next, please refer to the specific implementation process of S909A and S910A one by one. Fig. 8A The specific implementation process of S809A and S810A will not be described in detail.

[0294] In the sixth embodiment, taking UE1 as an example, UE1 requests to access the source satellite. If the source satellite determines that it cannot continue to serve UE1, it can request UE1 to access other available target satellites, and if the target satellite allows UE1 to access, the source satellite can send a random access response RAR to UE1 to instruct UE1 to access the target satellite; and also provide (or send) parameters in the existing calculation formula (such as the first TA of the target satellite determined by the source satellite) to UE1 through the source satellite; so that after UE1 identifies itself as an inter-satellite UE, it can directly calculate the TA of the target satellite through the existing calculation formula, thereby effectively completing the subsequent inter-satellite access process.

[0295] Embodiment seven:

[0296] Compared with the above-mentioned embodiment 5, the difference of the embodiment 7 is that: based on the above-mentioned Figure 3B In the solution, after the source satellite requests UE1 to access the target satellite that can serve UE1, the target satellite directly sends the scrambled DCI to UE1 (equivalent to the above Figure 3B The first indication information in the solution) is used to instruct the UE1 to access the target satellite across satellites. Fig.10 As shown, the process of the seventh embodiment is as follows:

[0297] Please refer to the specific implementation process of S1001 to S1004 one by one. Fig. 8A S801A to S804A (or Figure 4A The specific implementation process of S401A to S404A) will not be described in detail again.

[0298] S1005: The source satellite sends a first request message to the target satellite, where the first request message is used to request the UE1 to access the target satellite. Correspondingly, the target satellite receives the first request message from the source satellite.

[0299] S1005 can refer to Fig. 8A The method is implemented in S805A, but different from S805A, the first request information in S1005 carries the RA-RNTI and random preamble identifier RAPID of the source satellite, and the TA of the source satellite.

[0300] S1006: The target satellite sends a scrambled DCI to UE1, where the scrambled DCI is used to instruct UE1 to access the target satellite.

[0301] The specific implementation process of S1006 can be referred to Figure 4A The specific implementation process of the source satellite in S407A using its own RA-RNTI to scramble DCI1_0 is not described in detail.

[0302] S1007: The target satellite sends a random access response RAR to UE1. Correspondingly, UE1 receives the random access response RAR from the target satellite. The RAR carries the RAPID from the source satellite, the UL-GRANT and TC-RNTI, BI allocated by the target satellite to UE1, and the first TA of the target satellite.

[0303] The method for calculating the first TA of the target satellite can refer to Fig. 8A The method by which the source satellite determines the first TA of the target satellite in S808A.

[0304] Next, please refer to the specific implementation process of S1008 and S1009 one by one. Fig. 8A The specific implementation process of S809A and S810A will not be described in detail.

[0305] In the seventh embodiment, taking UE1 as an example, UE1 requests to access the source satellite. If the source satellite determines that it can no longer serve UE1, it can request UE1 to access other available target satellites. If the target satellite allows UE1 to access, it can directly send an encrypted DCI to UE1 to instruct UE1 to access the target satellite. The target satellite also provides (or sends) parameters in an existing calculation formula to UE1 (such as the first TA of the target satellite determined by the target satellite). As a result, after UE1 identifies itself as an inter-satellite UE, it can directly calculate the TA of the target satellite through the existing calculation formula, thereby effectively completing the subsequent inter-satellite access process.

[0306] Embodiment eight:

[0307] Compared with the above-mentioned embodiment 6, the difference of the embodiment 8 is that: based on Figure 3B In the solution, after the source satellite requests UE1 to access the target satellite that can serve UE1, the target satellite directly sends RAR to UE1 (equivalent to the above Figure 3B The first indication information in the solution) is used to instruct UE1 to access the target satellite across satellites. Compared with the above-mentioned embodiment 7, the main difference of this embodiment 8 is that: the target satellite sends a RAR to UE1 to instruct UE1 to access the target satellite across satellites. Fig.11 As shown, the specific process of the eighth embodiment is as follows:

[0308] Please refer to the specific implementation process of S1101 to S1104 one by one. Fig. 9A The specific implementation process of S901A to S904A will not be described in detail.

[0309] Please refer to the corresponding implementation process of S1105 Fig.10The specific implementation process of S1005 will not be described in detail.

[0310] S1106: The target satellite sends the scrambled DCI to UE1. Correspondingly, UE1 receives the scrambled DCI from the target satellite.

[0311] In S1106, the specific implementation process of the target satellite scrambling DCI can refer to Fig. 9A The way in which the source satellite scrambles the DCI in S907A (without changing the format of the DCI or the scrambled DCI) will not be described in detail again.

[0312] S1107: The target satellite sends a random access response RAR to UE1, which is used to instruct UE1 to access the target satellite. Correspondingly, UE1 receives the RAR from the target satellite. The RAR carries the RAPID from the source satellite, the UL-GRANT and TC-RNTI, BI allocated by the target satellite to UE1, and the first TA of the target satellite.

[0313] Among them, on the target satellite side, the structure of RAR and the way of designing RAR to indicate the ID and the first TA of the target satellite can refer to the structure of RAR and the way of designing RAR to indicate the ID and the first TA of the target satellite on the source satellite side (such as Fig. 9B The structure and design method shown in the figure are not described here.

[0314] Next, please refer to the specific implementation process of S1108 and S1109 one by one. Fig. 9A S909A and S910A (or Fig. 8A The specific implementation process of S809A and S810A) will not be described in detail.

[0315] In the eighth embodiment, taking UE1 as an example, UE1 requests to access the source satellite. If the source satellite determines that it can no longer serve UE1, it can request UE1 to access other available target satellites; if the target satellite allows UE1 to access, it can directly send a random access response RAR to UE1 to instruct UE1 to access the target satellite; and also provide (or send) parameters in the existing calculation formula to UE1 (such as the first TA of the target satellite determined by the target satellite); so that after UE1 identifies itself as an inter-satellite UE, it can directly calculate the TA of the target satellite through the existing calculation formula, thereby effectively completing the subsequent inter-satellite access process.

[0316] Regarding the above-mentioned embodiments 1 to 8, it should be noted that:

[0317] (1) The above-mentioned embodiments 1 to 8 may be implemented separately or in combination, and the embodiments of the present application are not limited thereto.

[0318] (2) The above description focuses on the differences between the first embodiment and the second embodiment. Except for the differences, the first to the eighth embodiments can refer to each other.

[0319] (3) The step numbers of the flowcharts described in Examples 1 to 8 are only examples of the execution process and do not constitute a limitation on the order of execution of the steps. There is no strict execution order between the steps that have no temporal dependency relationship with each other in the embodiments of the present application. In addition, not all the steps shown in the flowcharts are steps that must be executed, and some steps can be added or deleted based on the actual needs of each flowchart.

[0320] In the embodiments provided by the present application, the methods provided by the embodiments of the present application are introduced from the perspective of interaction between various devices. In order to implement the functions in the methods provided by the embodiments of the present application, the terminal device or the first satellite or the second satellite may include a hardware structure and / or a software module to implement the above functions in the form of a hardware structure, a software module, or a hardware structure plus a software module. Whether a function of the above functions is executed in the form of a hardware structure, a software module, or a hardware structure plus a software module depends on the specific application and design constraints of the technical solution.

[0321] The division of modules in the embodiments of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation. In addition, each functional module in each embodiment of the present application may be integrated into a processor, or may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated modules may be implemented in the form of hardware or in the form of software functional modules.

[0322] Same as above idea, Fig.12 As shown, the embodiment of the present application also provides a communication device 1200 for implementing the functions of the terminal device or the first satellite or the second satellite in the above method. For example, the communication device 1200 can be a software module or a chip system. In the embodiment of the present application, the chip system can be composed of a chip, or can include a chip and other discrete devices. The communication device 1200 may include: a communication unit 1201 and a processing unit 1202.

[0323] In the embodiment of the present application, the communication unit 1201 may also be referred to as a transceiver unit, and may include a sending unit and / or a receiving unit, which are respectively used to execute the steps of sending and receiving by the terminal device or the first satellite or the second satellite in the above method embodiment. The processing unit 1202 may be used to read instructions and / or data in the storage module so that the communication device 1200 implements the above method embodiment.

[0324] Optionally, the communication device 1200 may further include a storage unit 1203, which is equivalent to a storage module and can be used to store instructions and / or data.

[0325] The following, combined Figure 12 to Figure 13 The communication device provided in the embodiment of the present application is described in detail. It should be understood that the description of the device embodiment corresponds to the description of the method embodiment, so the contents not described in detail can be referred to above. Figure 3A-3B For the sake of brevity, the method embodiment will not be described in detail here.

[0326] The communication unit 1201 may also be referred to as a transceiver, a transceiver, a transceiver device, etc. The processing unit may also be referred to as a processor, a processing board, a processing module, a processing device, etc. Optionally, the device used to implement the receiving function in the communication unit 1201 may be regarded as a receiving unit, and the device used to implement the sending function in the communication unit 1201 may be regarded as a sending unit, that is, the communication unit 1201 includes a receiving unit and a sending unit. The communication unit may also be sometimes referred to as a transceiver, a transceiver, or a transceiver circuit, etc. The receiving unit may also be sometimes referred to as a receiver, a receiver, or a receiving circuit, etc. The sending unit may also be sometimes referred to as a transmitter, a transmitter, or a transmitting circuit, etc.

[0327] When the communication device 1200 executes the above embodiment Figure 3A In the process shown, when the terminal device:

[0328] The communication unit 1201 is used to send first random access information to a first satellite; the first random access information is used to request access to the first satellite; the communication unit 1201 is also used to receive first indication information; the first indication information is sent when the first satellite cannot serve the terminal device, and the first indication information is used to instruct the terminal device to access a second satellite. The processing unit 1202 is used to process data and / or information in the terminal device.

[0329] When the communication device 1200 executes the above embodiment Figure 3A When the first satellite in the process shown is:

[0330] The communication unit 1201 is used to receive first random access information from a terminal device; the first random access information is used to request access to the first satellite; the processing unit 1202 is used to determine that the terminal device cannot be served, and send a first request information to the second satellite through the communication unit 1201, where the first request information is used to request the terminal device to access the second satellite.

[0331] When the communication device 1200 executes the above embodiment Figure 3A When the second satellite in the process shown is:

[0332] The communication unit 1201 is used to receive a first request message from a first satellite; the first request message is used to request a terminal device to access the second satellite; the first request message is sent by the first satellite to the second satellite when the first satellite receives a first random access message from the terminal device and determines that the terminal device cannot be served; the first random access message is used by the terminal device to request access to the first satellite; the processing unit 1202 is used to determine whether the terminal device is allowed to access.

[0333] The above is just an example. The communication unit 1201 and the processing unit 1202 can also perform other functions. For more detailed description, please refer to Figure 3A-3B The relevant description in the method embodiment shown is not repeated here.

[0334] like Fig.13 The communication device 1300 provided in an embodiment of the present application is shown. Fig.13 The communication device shown can be Fig.12 The communication device 1300 is a hardware circuit implementation of the communication device shown in the figure. The communication device 1300 can be applied to the flowchart shown above to perform the functions of the terminal device or the first satellite or the second satellite in the above method embodiment. For the convenience of explanation, Fig.13 Only the main components of the communication device are shown.

[0335] like Fig.13 As shown, the communication device 1300 includes a communication interface 1301 and a processor 1302. The communication interface 1301 and the processor 1302 are coupled to each other. It is understandable that the communication interface 1301 can be a transceiver or an input-output interface, or an interface circuit such as a transceiver circuit. Optionally, the communication device 1300 may also include a memory 1303 for storing instructions executed by the processor 1302 or storing input data required by the processor 1302 to run the instructions or storing data generated after the processor 1302 runs the instructions.

[0336] When the communication device 1300 is used to implement Fig.12 In the method shown, the communication interface 1301 is used to implement the functions of the above-mentioned communication unit 1201, and the processor 1302 is used to implement the functions of the above-mentioned processing unit 1202.

[0337] The specific connection medium between the communication interface 1301, the processor 1302 and the memory 1303 is not limited in the embodiment of the present application. Fig.13 The memory 1303, the processor 1302 and the communication interface 1301 are connected via a communication bus 1304. Fig.13The communication bus 1304 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Fig.13 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0338] When the communication device is a chip, Fig.14 A simplified schematic diagram of a chip device structure is shown, wherein the chip 1400 includes an interface circuit 1401 and one or more processors 1402. Optionally, the chip 1200 may also include a bus.

[0339] Processor 1402 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above communication method can be completed by an integrated logic circuit of hardware in processor 1402 or an instruction in software form. The above processor 1402 can be a general-purpose processor, a digital communicator (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component. The disclosed methods and steps in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc.

[0340] The interface circuit 1401 can be used to send or receive data, instructions or information. The processor 1202 can use the data, instructions or other information received by the interface circuit 1401 to process, and can send the processing completion information through the interface circuit 1401.

[0341] Optionally, the chip further includes a memory 1403, which may include a read-only memory and a random access memory, and provides operation instructions and data to the processor. A portion of the memory 1403 may also include a non-volatile random access memory (NVRAM).

[0342] Optionally, the memory stores executable software modules or data structures, and the processor can perform corresponding operations by calling operation instructions stored in the memory (the operation instructions can be stored in the operating system).

[0343] Optionally, the chip may be used in the terminal device or the first satellite or the second satellite involved in the embodiment of the present application. Optionally, the interface circuit 1401 may be used to output the execution result of the processor 1402. The communication method provided by one or more embodiments of the present application may refer to the aforementioned embodiments, which will not be described in detail here.

[0344] It should be noted that the corresponding functions of the interface circuit 1401 and the processor 1402 can be implemented through hardware design, software design, or a combination of hardware and software, and there is no limitation here.

[0345] An embodiment of the present application also provides a computer-readable storage medium on which computer instructions for implementing the method executed by the terminal device or the first satellite or the second satellite in the above method embodiment are stored.

[0346] For example, when the computer program is executed by a computer, the computer can implement the method performed by the terminal device or the first satellite or the second satellite in the above method embodiment.

[0347] An embodiment of the present application also provides a computer program product comprising instructions, which, when executed by a computer, enables the computer to implement the method performed by the terminal device or the first satellite or the second satellite in the above method embodiment.

[0348] The embodiment of the present application also provides a chip, including a processor, which is used to call the computer program or computer instruction stored in the memory so that the processor executes the above Figure 3A-3B , Figures 4A-5A , Figure 6-Figure 7 , Figures 8A-9A ,as well as Fig.10 and Fig.11 The communication method of the embodiment shown.

[0349] In a possible implementation, the chip input corresponds to the above Figure 3A-3B , Figures 4A-5A , Figure 6-Figure 7 , Figures 8A-9A ,as well as Fig.10 and Fig.11 In the receiving operation of the embodiment shown, the output of the chip corresponds to the above Figure 3A-3B , Figures 4A-5A , Figure 6-Figure 7 , Figures 8A-9A ,as well as Fig.10 and Fig.11 The sending operation in the embodiment shown.

[0350] Optionally, the processor is coupled to the memory via an interface.

[0351] Optionally, the chip also includes a memory in which computer programs or computer instructions are stored.

[0352] The processor mentioned in any of the above places can be a general-purpose central processing unit, a microprocessor, an application-specific integrated circuit (ASIC), or one or more processors for controlling the above Figure 3A-3B , Figures 4A-5A , Figure 6-Figure 7 , Figures 8A-9A ,as well as Fig.10 and Fig.11 An integrated circuit for executing a program of a communication method of the embodiment shown. The memory mentioned in any of the above places can be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM), etc.

[0353] It should be noted that, for the sake of convenience and brevity of description, the explanation of the relevant contents and beneficial effects in any of the communication devices provided above may refer to the corresponding communication method embodiments provided above, and will not be repeated here.

[0354] In the present application, the communication devices may also include a hardware layer, an operating system layer running on the hardware layer, and an application layer running on the operating system layer. Among them, the hardware layer may include hardware such as a central processing unit (CPU), a memory management unit (MMU), and a memory (also called main memory). The operating system of the operating system layer may be any one or more computer operating systems that implement business processing through processes, such as Linux operating system, Unix operating system, Android operating system, iOS operating system, or Windows operating system. The application layer may include applications such as browsers, address books, word processing software, and instant messaging software.

[0355] The division of modules in the embodiments of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation. In addition, each functional module in each embodiment of the present application may be integrated into a processor, or may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated modules may be implemented in the form of hardware or in the form of software functional modules.

[0356] Through the description of the above implementation mode, it can be clearly understood by those skilled in the art that the embodiments of the present application can be implemented by hardware, firmware, or a combination thereof. When software is used for implementation, the above functions can be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein the communication media include any medium that facilitates the transmission of a computer program from one place to another. The storage medium can be any available medium that a computer can access. Taking this as an example but not limited to: a computer-readable medium can include RAM, ROM, electrically erasable programmable read only memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store a desired program code in the form of an instruction or data structure and can be accessed by a computer. In addition. Any connection can be appropriately a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, wireless, and microwave are included in the fixation of the medium. As used in the embodiments of the present application, disk and disc include compact disc (CD), laser disc, optical disc, digital video disc (DVD), floppy disk, and Blu-ray disc, where disks usually copy data magnetically and discs use lasers to copy data optically. The above combinations should also be included in the scope of protection of computer-readable media.

[0357] In short, the above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made according to the disclosure of the present application shall be included in the protection scope of the present application.

Claims

1. A communication method, characterized in that: Applied to terminal equipment, including: Sending first random access information to a first satellite; wherein the first random access information is used to request access to the first satellite; Receive first indication information; the first indication information is sent when the first satellite cannot serve the terminal device, and the first indication information is used to instruct the terminal device to access the second satellite.

2. The method according to claim 1, characterized in that The receiving first indication information includes: receiving the first indication information from the first satellite; or The first indication information is received from the second satellite.

3. The method according to claim 1 or 2, characterized in that: The first indication information is scrambled downlink control information; the scrambled downlink control information is obtained by scrambling the first downlink control information according to the random access radio network temporary identifier RA-RNTI of the first satellite, and a newly added first bit information in the first downlink control information is used to indicate the identification information of the second satellite; or, the scrambled downlink control information is obtained by scrambling the downlink control information according to the RA-RNTI of the first satellite and the identification information of the second satellite.

4. The method according to claim 1 or 2, characterized in that: The first indication information is first random access response information used to respond to the first random access information; the reserved bit information in the first random access response information is used to indicate that the first random access response information is random access response information for inter-satellite access, and the timing advance information field in the first random access response information is used to indicate the identification information of the second satellite.

5. The method according to any one of claims 1 to 4, characterized in that: The method further comprises: Acquire a public TA of the second satellite; Acquire a downlink timing of the first satellite and a downlink timing of the second satellite; determining a target TA of the second satellite according to the common TA of the second satellite, the downlink timing of the first satellite, and the downlink timing of the second satellite; Based on the target TA of the second satellite, the second satellite is accessed.

6. The method according to claim 5, characterized in that The target TA of the second satellite satisfies the following formula: T TA =(N TA,UE-specfic +N TA,common +N TA,offset )×T C +2×(DL1-DL2); Among them, T TA represents the target TA of the second satellite, N TA,UE-specfic represents the TA of the first satellite, where the TA of the first satellite is determined according to the ephemeris information of the first satellite and the location information of the terminal device; N TA,common represents the common TA of the second satellite, N TA,offset Indicates the preset offset, T C is the minimum time unit, DL1 is the downlink timing of the first satellite, and DL2 is the downlink timing of the second satellite.

7. The method according to claim 5 or 6, characterized in that: The acquiring the downlink timing of the first satellite and the downlink timing of the second satellite includes: A synchronization signal of the first satellite and a synchronization signal of the second satellite are received respectively, wherein the synchronization signal of the first satellite carries a downlink timing of the first satellite, and the synchronization signal of the second satellite carries a downlink timing of the second satellite.

8. The method according to claim 1 or 2, characterized in that: The first indication information is first random access response information used to respond to the first random access information; the temporary cell TC-RNTI information field in the first random access response information is used to indicate the identification information of the second satellite; or a newly added second bit information in the first random access response information is used to indicate the identification information of the second satellite.

9. The method according to claim 8, characterized in that The first random access response information also includes a first TA of the second satellite, where the first TA of the second satellite is equal to the TA of the first satellite, or the first TA of the second satellite is determined according to the TA of the first satellite and a timing difference between the first satellite and the second satellite; The method further comprises: Acquire a public TA of the second satellite; Obtaining a target TA of the second satellite according to a first TA of the second satellite and a common TA of the second satellite; Based on the target TA of the second satellite, the second satellite is accessed.

10. The method according to claim 9, characterized in that The target TA of the second satellite satisfies the following formula: T TA =(N TA,UE-specfic +N TA +N TA,common +N TA,offset )×T C ; Among them, T TA represents the target TA of the second satellite; N TA,UE-specfic represents a second TA of the second satellite, where the second TA of the second satellite is determined according to the ephemeris information of the second satellite and the location information of the terminal device; N TA represents the first TA of the second satellite; N TA,common N represents the common TA of the second satellite; TA,offset Indicates the preset offset, T C The minimum time unit.

11. The method according to claim 9 or 10, characterized in that: The acquiring the public TA of the second satellite includes: A broadcast signal of the second satellite is received, where the broadcast signal of the second satellite carries a public TA of the second satellite.

12. A communication method, characterized in that: Applied to the first satellite, including: receiving first random access information from a terminal device; the first random access information is used to request access to the first satellite; It is determined that the terminal device cannot be served, and first request information is sent to the second satellite, where the first request information is used to request the terminal device to access the second satellite.

13. The method according to claim 12, characterized in that The method further comprises: First response information is received from the second satellite, where the first response information is used to indicate that the second satellite allows the terminal device to access.

14. The method according to claim 13, characterized in that The method further comprises: Sending first indication information to the terminal device, where the first indication information is used to instruct the terminal device to access the second satellite.

15. The method according to claim 14, characterized in that The first indication information is scrambled downlink control information; The scrambled downlink control information is obtained by scrambling the first downlink control information according to the random access radio network temporary identifier RA-RNTI of the first satellite, and the first bit information is newly added in the first downlink control information to indicate the identification information of the second satellite; or The scrambled downlink control information is obtained by scrambling the downlink control information according to the RA-RNTI of the first satellite and the identification information of the second satellite.

16. The method according to claim 14, characterized in that The first indication information is first random access response information used to respond to the first random access information; The reserved bit information in the first random access response information is used to indicate that the first random access response information is random access response information for inter-satellite access, and the timing advance information field in the first random access response information is used to indicate identification information of the second satellite.

17. The method according to claim 14, characterized in that The first indication information is first random access response information used to respond to the first random access information; The temporary cell TC-RNTI information field in the first random access response information is used to indicate the identification information of the second satellite; or a second bit information is newly added in the first random access response information to indicate the identification information of the second satellite.

18. The method according to claim 17, characterized in that The first random access response information also includes a first TA of the second satellite; wherein the first TA of the second satellite is equal to the TA of the first satellite, or the first TA of the second satellite is determined based on the TA of the first satellite and the timing difference between the first satellite and the second satellite.

19. A communication method, characterized in that: Applicable to the second satellite, including: receiving a first request message from a first satellite; the first request message is used to request a terminal device to access the second satellite; the first request message is sent by the first satellite to the second satellite when the first satellite receives a first random access message from the terminal device and determines that the terminal device cannot be served; the first random access message is used by the terminal device to request access to the first satellite; The terminal device is allowed to access.

20. The method according to claim 19, characterized in that The method further comprises: sending first response information to the first satellite, so that the first satellite sends first indication information to the terminal device after receiving the first response information; or Sending the first indication information to the terminal device; The first indication information is used to instruct the terminal device to access the second satellite.

21. The method according to claim 20, characterized in that The first indication information is scrambled downlink control information; The scrambled downlink control information is obtained by scrambling the first downlink control information according to the random access radio network temporary identifier RA-RNTI of the first satellite, and the first bit information is newly added in the first downlink control information to indicate the identification information of the second satellite; or The scrambled downlink control information is obtained by scrambling the downlink control information according to the RA-RNTI of the first satellite and the identification information of the second satellite.

22. The method according to claim 20, characterized in that The first indication information is first random access response information used to respond to the first random access information; The reserved bit information in the first random access response information is used to indicate that the first random access response information is random access response information for inter-satellite access, and the timing advance information field in the first random access response information is used to indicate identification information of the second satellite.

23. The method according to claim 20, characterized in that The first indication information is first random access response information used to respond to the first random access information; The temporary cell TC-RNTI information field in the first random access response information is used to indicate the identification information of the second satellite; or a second bit information is newly added in the first random access response information to indicate the identification information of the second satellite.

24. The method according to claim 23, characterized in that The first random access response information also includes a first TA of the second satellite; wherein the first TA of the second satellite is equal to the TA of the first satellite, or the first TA of the second satellite is determined based on the TA of the first satellite and the timing difference between the first satellite and the second satellite.

25. A communication device, characterized in that: The method comprises a module for executing the method according to any one of claims 1 to 11, or a module for executing the method according to any one of claims 12 to 18, or a module for executing the method according to any one of claims 19 to 24.

26. A communication device, characterized in that: It includes a processor and an interface circuit, wherein the interface circuit is used to receive signals from other communication devices outside the communication device and transmit them to the processor or send signals from the processor to other communication devices outside the communication device, and the processor is used to implement the method as described in any one of claims 1-11, or implement the method as described in any one of claims 12-18, or implement the method as described in any one of claims 19-24 through logic circuits or execution code instructions.

27. A computer-readable storage medium, characterized in that: The storage medium stores a computer program or an instruction, and when the computer program or the instruction is executed by the communication device, the method according to any one of claims 1 to 24 is implemented.

28. A chip system, characterized in that: include: A processor, wherein the processor is configured to execute the method according to any one of claims 1 to 24.

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