Communication method, device and system

Abstract

The invention discloses a communication method, device and system, relates to the field of communication, and aims to solve the problem that a terminal cannot accurately determine absolute time of epoch time in satellite ephemeris information and guarantee normal use of the satellite ephemeris information. The method comprises the following steps: a first network device obtains first information and sends the first information to a terminal; and the terminal receives the first information and determines the absolute time of the epoch time according to the first information. Wherein the first information is used for indicating a relative relationship between epoch time and first time; the first time is time for receiving satellite ephemeris information; the satellite ephemeris information carries epoch time. The first network device is a network device which provides service for the terminal device at present. The scheme of the invention can be widely applied to the fields of communication technology, artificial intelligence, Internet of Vehicles, smart home networking and the like.

Description

TECHNICAL FIELD

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

[0002] Non-terrestrial network (NTN) is a general term for networks involving flying objects, including satellite communication systems, high altitude platform systems (HAPS) and air-to-ground networks. In the NTN scenario, satellite communication equipment, i.e. communication equipment carried or deployed on a satellite, such as a satellite base station, is in a high-speed motion state compared to user equipment (UE), so that the relative position and the rate of change of the relative speed of the UE and the satellite communication equipment are high. To this end, the UE needs to calculate the future or past state (position and / or speed) of the satellite communication equipment based on satellite ephemeris information in real time to calibrate its receiving and transmitting parameters and ensure normal access of uplink and downlink services.

[0003] Among them, the satellite ephemeris information is used to provide the state (position and / or speed) of the satellite communication equipment at an instantaneous time point (or referred to as instantaneous state) to the UE. The satellite ephemeris information includes an epoch time and position state information. The epoch time represents an instantaneous time (or referred to as an instantaneous time point), and the position state information is used to indicate the state of the satellite communication equipment. The epoch time in the satellite ephemeris information is composed of a system frame number (SFN) and a sub-frame number. The SFN ranges from 0 to 1023, and the time length of each SFN is 10 ms. The sub-frame number ranges from 0 to 9, and the time of each sub-frame number is 1 ms. Therefore, the maximum representation time range of the epoch time is 0-10.239 seconds (s). To calculate the future or past state of the satellite communication equipment relative to the epoch time, the absolute time corresponding to the epoch time needs to be determined, and then the state of the satellite communication equipment at any time is calculated according to the state of the satellite communication equipment at the absolute time of the epoch time.

[0004] However, due to factors such as fast changes in channel link characteristics and non-ideal implementation of the UE, the determination of the absolute time of the epoch time is inaccurate, which causes errors in the calculation of the state of the satellite communication equipment, making it difficult to accurately receive and demodulate the signals of the satellite communication equipment, and even leading to communication link interruption. SUMMARY

[0005] The embodiments of the present application provide a communication method, device and system to solve the problem of inaccurate determination of the absolute time of the epoch time in the satellite ephemeris information by the terminal, and to ensure the normal use of the satellite ephemeris information.

[0006] To achieve the above object, the application adopts the following technical solutions:

[0007] In a first aspect, an embodiment of the application provides a communication method, which can be executed by a terminal device, the terminal device can be a terminal device or a functional module or a chip in the terminal device, and is taken as an example of being executed by the terminal device, the method comprises: the terminal device receives first information, and determines an absolute time of an epoch time according to the first information. The first information is used to indicate a relative relationship between the epoch time and a first time; the first time is a time of receiving satellite ephemeris information; and the satellite ephemeris information carries the epoch time.

[0008] In the application, the relative relationship can refer to a time relative relationship, i.e. a relative time sequence of two times. Since there is only one relative relationship, the relative relationship between the epoch time and the first time indicated by the first information is unique based on the first method, and the terminal device can select a unique candidate absolute time of the epoch time as the absolute time of the epoch time. Therefore, in the case that the first information directly or indirectly indicates the relative relationship between the epoch time and the first time, the terminal device can accurately determine the absolute time of the epoch time in the satellite ephemeris information, thereby ensuring that the satellite ephemeris information can be normally used.

[0009] In a possible design, the first information comprises the relative relationship between the epoch time and the first time, i.e. the first information directly indicates the relative relationship between the epoch time and the first time, and the communication method based on the first method further comprises: the terminal device receives the satellite ephemeris information at the first time.

[0010] Based on the possible design, the first information directly indicates the relative relationship between the epoch time and the first time, so that the terminal device can select a unique candidate absolute time of the epoch time as the absolute time of the epoch time according to the epoch time carried by the satellite ephemeris information, the first time of receiving the satellite ephemeris information, and the relative relationship between the epoch time and the first time, thereby accurately determining the absolute time of the epoch time in the satellite ephemeris information, and ensuring that the satellite ephemeris information can be normally used.

[0011] In a possible design, the first information is used to indicate the relative relationship between the epoch time and the first time, which comprises: the first information is used to indicate a sequence of the epoch time and the first time, and / or the first information is used to indicate an absolute time difference between the epoch time and the first time.

[0012] Based on the possible design, multiple ways of representing the relative relationship between the epoch time and the first time by the first information are given, so that the present scheme can be flexibly applied to various communication scenarios.

[0013] In a possible design, the absolute time of the epoch time is determined according to the first information, including: selecting a candidate absolute time of the epoch time from candidate absolute times of the epoch time as the absolute time of the epoch time according to the first information, wherein the chronological order of the candidate absolute time and the first time satisfies the chronological order of the epoch time and the first time indicated by the first information, and the candidate absolute times of the epoch time include times corresponding to the epoch time in each equivalent superframe, and a time length of the equivalent superframe is a preset value.

[0014] Based on this possible design, the terminal device can determine the absolute time of the epoch time according to the chronological order of the epoch time and the first time indicated by the first information, in a case where the first information is used to indicate the chronological order of the epoch time and the first time.

[0015] In a possible design, the chronological order of the epoch time and the first time includes: the epoch time is earlier than the first time, or the epoch time is later than the first time, or the epoch time is equal to the first time.

[0016] Based on this possible design, in a case where the first information indicates the chronological order of the epoch time and the first time, a possible unique relative time relationship between the epoch time and the first time is given, and the unique relative relationship between the epoch time and the first time is indicated in a manner of the chronological order of the epoch time and the first time.

[0017] In a possible design, the absolute time of the epoch time is determined according to the first information, including: selecting a candidate absolute time of the epoch time from candidate absolute times of the epoch time as the absolute time of the epoch time according to the first information, wherein an absolute time difference between the candidate absolute time and a time obtained by adding the absolute time difference indicated by the first information to the first time is less than a preset threshold, and the candidate absolute times of the epoch time include times corresponding to the epoch time in each equivalent superframe, and a time length of the equivalent superframe is a preset value.

[0018] Based on this possible design, the terminal device can determine the absolute time of the epoch time according to the absolute time difference between the epoch time and the first time indicated by the first information, in a case where the first information is used to indicate the absolute time difference between the epoch time and the first time.

[0019] In a possible design, the first information is satellite ephemeris information, and the epoch time is obtained according to a preset constraint condition, and the constraint condition is used to constrain the relative time relationship between the epoch time and the first time, that is, the first information indirectly indicates the relative relationship between the epoch time and the first time.

[0020] Based on the possible design, the relative time relationship between the epoch time carried in the first information and the first time satisfies the preset constraint condition, and the first information indirectly indicates the unique relative relationship between the epoch time and the first time, so that the terminal device can obtain the relative time relationship between the epoch time and the first time when the epoch time carried in the first information is received.

[0021] In a possible design, the satellite ephemeris information is satellite ephemeris information of a target cell; the preset constraint condition is that the epoch time is less than the first time; and the target cell is a cell that takes over the service cell to provide services for the terminal device, and the service cell is a cell that currently provides services for the terminal device.

[0022] Based on the possible design, the preset constraint condition that the epoch time carried in the satellite ephemeris information of the target cell satisfies is given in the case where the satellite ephemeris information is satellite ephemeris information of the target cell, so that the terminal device indirectly determines that the relative relationship between the epoch time and the first time is that the epoch time is less than the first time after the epoch time is obtained.

[0023] In a possible design, the satellite ephemeris information is satellite ephemeris information of a neighbor cell; the preset constraint condition is that the epoch time and the first time are time points in a same preset time period; and the neighbor cell is a cell adjacent to the service cell, and the service cell is a cell that currently provides services for the terminal device.

[0024] Based on the possible design, the preset constraint condition that the epoch time carried in the satellite ephemeris information of the neighbor cell satisfies is given in the case where the satellite ephemeris information is satellite ephemeris information of the neighbor cell, so that the terminal device indirectly determines that the relative relationship between the epoch time and the first time is that the epoch time and the first time are time points in a same preset time period after the epoch time is obtained.

[0025] In a possible design, the length of the preset time period is less than or equal to a preset threshold. Based on the possible design, various possibilities of the length of the preset time period are given, so that the present scheme can be flexibly applied to various communication scenarios.

[0026] In a possible design, the first information is carried in system information SI; or the first information is carried in radio resource control (RRC) signaling. Based on the possible design, the first information can be carried in various information, so that the present scheme can be flexibly applied to various communication scenarios.

[0027] In a second aspect, an embodiment of the present application provides a communication method, which can be executed by a first network device, the first network device can be a first network device or a functional module or a chip in the first network device, taking the first network device as an example, the method comprises: the first network device acquires first information and transmits the first information. The first information is used to indicate the relative relationship between an epoch time and a first time. The first time is the time of receiving satellite ephemeris information. The satellite ephemeris information carries the epoch time.

[0028] In the present application, the relative relationship can refer to the relative time sequence of two times. Since there is only one relative relationship, based on the method of the second aspect, when the first network device acquires the first information used to indicate the relative relationship between the epoch time and the first time, the relative relationship between the epoch time and the first time indicated by the first information transmitted by the first network device is unique, so that the terminal device can receive the first information and select the absolute time of the candidate epoch time as the absolute time of the epoch time directly or indirectly according to the direct or indirect indication of the first information, thereby accurately determining the absolute time of the epoch time in the satellite ephemeris information and ensuring that the satellite ephemeris information can be normally used.

[0029] In a possible design, the first information includes the relative relationship between the epoch time and the first time, i.e., the first information directly indicates the relative relationship between the epoch time and the first time. The method of the second aspect further comprises: transmitting the satellite ephemeris information.

[0030] Based on the possible design, the first information directly indicates the relative relationship between the epoch time and the first time, so that the terminal device can acquire the epoch time through the satellite ephemeris information when the relative relationship between the epoch time and the first time is acquired.

[0031] In a possible design, the first information is used to indicate the relative relationship between the epoch time and the first time, including: the first information is used to indicate the sequence of the epoch time and the first time, and / or the first information is used to indicate the absolute time difference between the epoch time and the first time.

[0032] Based on the possible design, the present application provides multiple ways of representing the relative relationship between the epoch time and the first time by the first information, so that the present application can be flexibly applied to various communication scenarios.

[0033] In a possible design, the first network device acquires the first information, including: the first network device acquires the epoch time; determines the relative relationship between the epoch time and the first time according to the epoch time and the first time; and acquires the first information according to the relative relationship between the epoch time and the first time.

[0034] Based on the possible design, the first network device can determine the relative relationship between the epoch time and the first time in a case that the epoch time and the first time are acquired, to achieve the purpose of acquiring the first information.

[0035] In a possible design, the epoch time is an epoch time of a target cell, and the acquiring the epoch time includes: sending a handover request; the handover request is used to request to allocate a resource for the terminal device; and in response to the handover request, receiving the epoch time of the target cell; the target cell is a cell that takes over the service cell to provide a service for the terminal device, and the service cell is a cell that currently provides a service for the terminal device.

[0036] Based on the possible design, the first network device can acquire the epoch time of the target cell through the handover request in a case that the epoch time is an epoch time of the target cell.

[0037] In a possible design, the order of the epoch time and the first time includes: the epoch time is earlier than the first time, or the epoch time is later than the first time, or the epoch time is equal to the first time.

[0038] Based on the possible design, in a case that the first information indicates the order of the epoch time and the first time, a possible unique relative time relationship between the epoch time and the first time is given, to achieve the purpose of indicating the unique relative relationship between the epoch time and the first time through the order of the epoch time and the first time.

[0039] In a possible design, the first information is satellite ephemeris information, and the epoch time is obtained according to a preset constraint condition, and the constraint condition is used to constrain the relative time relationship between the epoch time and the first time. That is, the first information indirectly indicates the relative relationship between the epoch time and the first time.

[0040] Based on the possible design, the relative time relationship between the epoch time and the first time carried in the first information satisfies the preset constraint condition, and at this time, the first information indirectly indicates the unique relative relationship between the epoch time and the first time, to achieve the purpose that the terminal device can acquire the unique relative time relationship between the epoch time and the first time in a case that the epoch time carried in the first information is received.

[0041] In a possible design, the first information is satellite ephemeris information, and the acquiring the first information includes: obtaining the epoch time according to a preset constraint condition; obtaining position state information corresponding to the epoch time according to the epoch time; the position state information is used to indicate a position and / or a speed of a satellite communication device; and carrying the epoch time and the position state information corresponding to the epoch time in the satellite ephemeris information.

[0042] Based on the possible design, in a case where the first information is satellite ephemeris information of the target cell, the first network device can obtain the epoch time through the preset constraint condition, and further obtain the position state information corresponding to the epoch time, so as to achieve the purpose of obtaining the first information.

[0043] In a possible design, the first information is satellite ephemeris information of the target cell, and the position state information corresponding to the epoch time is obtained according to the epoch time, including: sending a first request message carrying the epoch time, the first request message being used to request the position state information corresponding to the epoch time; and in response to the first request message, receiving second information, the second information including the position state information corresponding to the epoch time.

[0044] Based on the possible design, in a case where the first information is satellite ephemeris information of the target cell, the first network device can obtain the position state information corresponding to the epoch time through the first request message.

[0045] In a possible design, the satellite ephemeris information is satellite ephemeris information of the target cell; and the preset constraint condition is that the epoch time is less than the first time; wherein the target cell is a cell that takes over the service cell to provide services for the terminal device, and the service cell is a cell that currently provides services for the terminal device.

[0046] Based on the possible design, in a case where the satellite ephemeris information is satellite ephemeris information of the target cell, the preset constraint condition that the epoch time carried in the satellite ephemeris information of the target cell satisfies is given, so that after the terminal device obtains the epoch time, the relative relationship between the epoch time and the first time is indirectly determined as the epoch time being less than the first time.

[0047] In a possible design, the satellite ephemeris information is satellite ephemeris information of the neighbor cell; and the preset constraint condition is that the epoch time and the first time are time points in a same preset time period; wherein the neighbor cell is a cell adjacent to the service cell, and the service cell is a cell that currently provides services for the terminal device.

[0048] Based on the possible design, in a case where the satellite ephemeris information is satellite ephemeris information of the neighbor cell, the preset constraint condition that the epoch time carried in the satellite ephemeris information of the neighbor cell satisfies is given, so that after the terminal device obtains the epoch time, the relative relationship between the epoch time and the first time is indirectly determined as the epoch time and the first time being time points in a same preset time period.

[0049] In a possible design, the length of the preset time period is less than or equal to a preset threshold. Based on the possible design, multiple possibilities of the length of the preset time period are given, so that the scheme can be flexibly applied to various communication scenarios.

[0050] In a third aspect, the present application provides a communication apparatus, which can be a terminal device or a chip or system on chip in the terminal device, or a functional module in the terminal device for implementing the method in the first aspect or any possible design of the first aspect. The communication apparatus can implement the functions of the terminal device in the first aspect or any possible design of the first aspect, and the functions can be implemented by hardware or software. The hardware or software includes one or more modules corresponding to the functions. For example, the communication apparatus can include a transceiver and a processing unit. Wherein,

[0051] The transceiver is configured to receive the first information, and the first information is used to indicate the relative relationship between the epoch time and the first time, and the first time is the time of receiving the satellite ephemeris information, and the satellite ephemeris information carries the epoch time.

[0052] The processing unit is configured to determine the absolute time of the epoch time according to the first information.

[0053] Specifically, the execution actions of each unit of the communication apparatus can refer to the first aspect or any possible design of the first aspect, and will not be repeated here.

[0054] In a fourth aspect, the present application provides a communication apparatus, which can be a first network device or a chip or system on chip in the first network device, or a functional module in the first network device for implementing the method in the second aspect or any possible design of the second aspect. The communication apparatus can implement the functions of the first network device in the second aspect or any possible design of the second aspect, and the functions can be implemented by hardware or software. The hardware or software includes one or more modules corresponding to the functions. For example, the communication apparatus can include a processing unit and a transceiver. Wherein,

[0055] The processing unit is configured to obtain the first information, and the first information is used to indicate the relative relationship between the epoch time and the first time, and the first time is the time of receiving the satellite ephemeris information, and the satellite ephemeris information carries the epoch time.

[0056] The transceiver is configured to send the first information.

[0057] Specifically, the execution actions of each unit of the communication apparatus can refer to the second aspect or any possible design of the second aspect, and will not be repeated here.

[0058] In a fifth aspect, the present application provides a communication apparatus. In a possible design of the communication apparatus, the communication apparatus includes a processor. The processor is configured to support the communication apparatus to perform the communication method in the first aspect or any possible design of the first aspect, or the processor is configured to support the communication apparatus to perform the communication method in the second aspect or any possible design of the second aspect. In another possible design of the communication apparatus, the communication apparatus further includes a memory. The memory is configured to store instructions and / or data. When the communication apparatus is running, the processor executes the computer-executable instructions stored in the memory, so that the communication apparatus performs the communication method in the first aspect or any possible design of the first aspect, or performs the communication method in the second aspect or any possible design of the second aspect.

[0059] In a sixth aspect, the present application provides a communication system. The communication system includes the communication apparatus in the third aspect and the communication apparatus in the fourth aspect.

[0060] In a seventh aspect, the present application provides a computer-readable storage medium. The computer-readable storage medium stores computer instructions. When the computer instructions are executed on a computer, the computer instructions cause the computer to perform the communication method in the first aspect or any possible design of the first aspect, or cause the computer to perform the communication method in the second aspect or any possible design of the second aspect.

[0061] In an eighth aspect, the present application provides a computer program product. The computer program product includes computer instructions. When the computer instructions are executed on a computer, the computer instructions cause the computer to perform the communication method in the first aspect or any possible design of the first aspect, or cause the computer to perform the communication method in the second aspect or any possible design of the second aspect. BRIEF DESCRIPTION OF DRAWINGS

[0062] Figure 1 A schematic diagram of a transparent architecture in an NTN scenario provided by an embodiment of the present application;

[0063] Figure 2 A schematic diagram of a regenerative architecture in an NTN scenario provided by an embodiment of the present application;

[0064] Figure 3 A schematic diagram of a speed and position vector format provided by an embodiment of the present application;

[0065] Figure 4 A schematic diagram of an orbit parameter format provided by an embodiment of the present application;

[0066] Figure 5a A schematic diagram of a T ref and T E1 provided by an embodiment of the present application;

[0067] Figure 5b A T ref and T E2 schematic diagram;

[0068] Figure 6 A T ref and T E3 schematic diagram;

[0069] Figure 7 A SFN0-axis time distribution schematic diagram is provided for the embodiment of the application;

[0070] Figure 8 A communication system schematic diagram is provided for the embodiment of the application;

[0071] Figure 9 A satellite communication system schematic diagram is provided for the embodiment of the application;

[0072] Figure 10 A communication method flow schematic diagram is provided for the embodiment of the application;

[0073] Figure 11 A communication method flow schematic diagram is provided for the embodiment of the application;

[0074] Figure 12 A SFN1-axis time distribution schematic diagram is provided for the embodiment of the application;

[0075] Figure 13 A SFN1-axis time distribution schematic diagram is provided for the embodiment of the application;

[0076] Figure 14 A communication method flow schematic diagram is provided for the embodiment of the application;

[0077] Figure 15 A SFN1-axis time distribution schematic diagram is provided for the embodiment of the application;

[0078] Figure 16 A communication method flow schematic diagram is provided for the embodiment of the application;

[0079] Figure 17 A communication method flow schematic diagram is provided for the embodiment of the application;

[0080] Figure 18 A communication device structure schematic diagram is provided for the embodiment of the application;

[0081] Figure 19 A communication device structure schematic diagram is provided for the embodiment of the application;

[0082] Figure 20 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application. Detailed Implementation

[0083] Before introducing the embodiments of this application, some technical terms involved in the embodiments of this application will be explained. It should be noted that the following explanations are for the purpose of making the embodiments of this application easier to understand, and should not be regarded as a limitation on the scope of protection claimed by the embodiments of this application.

[0084] Non-terrestrial networks (NTNs) are a general term for networks involving flying objects. They achieve wireless communication through satellite or drone platforms, providing ubiquitous coverage to terminals regardless of terrain. In particular, NTNs can be used to extend network coverage in areas where terrestrial network equipment is not readily available, such as deserts, oceans, and high-altitude regions. NTNs can include satellite communication systems, high-altitude platform systems (HAPS), and air-to-ground networks. Satellite communication systems rely on onboard platforms, primarily including low-Earth orbit (LEO), medium-Earth orbit (MEO), and geostationary earth orbit (GEO) satellites.

[0085] In the NTN scenario, satellite communication systems have two typical architectures: transparent payload and regenerative payload.

[0086] In a transparent transmission architecture, satellite communication equipment is responsible for data forwarding but has no data processing capabilities. Figure 1 This is a schematic diagram of a pass-through architecture in an NTN scenario. Figure 1 As shown, the access network equipment is located on the ground, and the satellite communication equipment is connected to the access network equipment through a gateway station. Data sent from the terminal to the satellite communication equipment is forwarded by the satellite communication equipment to the access network equipment, where it is processed. The link between the satellite communication equipment and the terminal is a service link, and the link between the satellite communication equipment and the access network equipment is a feeder link.

[0087] Under the regenerative architecture, satellite communication equipment has all or part of the functions of a base station, meaning that satellite communication equipment can perform data processing. Figure 2 This is a schematic diagram of a regeneration architecture in an NTN scenario. (Example)Figure 2 As shown, the data sent from the terminal to the satellite communication equipment is processed by the satellite communication equipment. The link between the satellite communication equipment and the terminal is a service link.

[0088] In an NTN scenario, the cell covered by satellite communication equipment can be called an NTN cell, which can be divided into the following three categories:

[0089] Earth-fixed: The coverage area of ​​this type of NTN cell is fixed to a specific area on the ground, i.e., continuous fixed-point coverage. NTN cells covered by geostationary orbit satellite communication equipment belong to the earth-fixed type. Geostationary orbit satellite communication equipment refers to communication equipment carried or deployed on geostationary orbit satellites.

[0090] Quasi-earth-fixed: The coverage area of ​​this type of NTN cell is fixed to a specific area on the ground for a period of time, and then changes to another area on the ground after that period; that is, it provides fixed-point coverage for a specific time period. Cells covered by low-Earth orbit (LEO) and medium-Earth orbit (MEO) satellite communication equipment are this type of NTN cell. LEO satellite communication equipment refers to communication equipment carried or deployed on LEO satellites. MEO satellite communication equipment refers to communication equipment carried or deployed on MEO satellites.

[0091] Earth-moving: The coverage area of ​​this type of NTN cell moves on the ground. Cells covered by low-Earth orbit (LEO) and medium-Earth orbit (MEO) satellite communication equipment are of this type.

[0092] In NTN scenarios, satellite communication equipment is in a state of high-speed motion relative to the terminal, resulting in a high rate of change in the relative position and relative speed between the terminal and the satellite communication equipment. The terminal needs to calculate the position and / or speed of the satellite communication equipment in real time based on satellite ephemeris information, and calculate relevant parameters such as Doppler frequency offset, timing advance (TA), and propagation delay. Based on these relevant parameters, the terminal calibrates its own receiving and transmitting parameters to ensure normal access to uplink and downlink services.

[0093] Satellite ephemeris information is used to provide the UE with the instantaneous status (position and / or velocity) of the satellite communication equipment. Satellite ephemeris information includes epoch time and position status information.

[0094] An epoch time represents an instantaneous time (or a point in time), consisting of a system frame number (SFN) and a sub-frame number. The SFN ranges from 0 to 1023, with each SFN lasting 10 ms. The sub-frame number ranges from 0 to 9, with each sub-frame number lasting 1 ms. Therefore, the maximum range of epoch time is 0 to 10.239 seconds. Terminals can obtain the epoch time from the epoch time field in satellite ephemeris information. The epoch time field in satellite ephemeris information indicates an SFN and a sub-frame number.

[0095] Location status information is used to indicate the status of satellite communication equipment.

[0096] Satellite ephemeris information exists in the following two formats:

[0097] Velocity and position vector format: Figure 3 This is a schematic diagram of the velocity and position vector format. (For example...) Figure 3 As shown, the position status information in the velocity and position vector format includes the velocity and position vectors of the satellite communication equipment in the X, Y, and Z axes in the Earth-Centered Earth-Fixed (ECEF) coordinate system. When the position status information is represented by the velocity and position vector format, the velocity and position of the satellite communication equipment indicated by the position status information are the velocity and position of the satellite communication equipment at the absolute time of the epoch in the satellite ephemeris information.

[0098] Orbital parameters (also known as six-element numbers) format: Figure 4 This is a schematic diagram of the orbital parameter format. The positional information in the orbital parameter format includes the following six parameters: semi-major axis, eccentricity, orbital inclination, right ascension of the ascending node, argument of periapsis, and mean anomaly. The semi-major axis is... Figure 4 The shown satellite orbit's major axis is half of its orbital length. The eccentricity is... Figure 4 The ratio of the distance between the two foci to the length of the major axis of the satellite orbit shown. The orbital inclination is... Figure 4 In this context, i0 represents the inclination of the satellite's orbital plane relative to the equatorial plane; specifically, the orbital inclination is the angle between the satellite's orbital plane and the equatorial plane at the absolute time of the epoch in the satellite's ephemeris information. The ascending node is... Figure 4 Ω0 is Figure 4 The ecliptic longitude of the ascending and descending nodes. The argument of perigee. Figure 4 ω is fromFigure 4 The angle of perigee measured counterclockwise from the midpoint of the ascending node along the satellite's orbit. The average perigee angle is... Figure 4 M0 is the orbital angle of the satellite communication equipment relative to the center point on the auxiliary circle. These six parameters can be used to determine the position and / or velocity of the satellite communication equipment.

[0099] Satellite ephemeris information can be carried in system information (SI) or radio resource control (RRC) signaling. When satellite ephemeris information is carried in system information, if the epoch time field in the satellite ephemeris information is empty, the end point of the system information window (SI window) containing that system information is taken as the epoch time.

[0100] Optionally, the SI carrying satellite ephemeris information includes, but is not limited to, system information block 19 (SIB19). When the system information is SIB19, the network device currently providing services to the terminal can provide the terminal with the satellite ephemeris information of the serving cell and / or neighboring cells through SIB19. In this case, the time the network device sends the satellite ephemeris information, the time the terminal receives the SIB19, and the SFN and subframe number indicated by the epoch time field in the satellite ephemeris information are all timestamps on the SFN axis of the serving cell. The serving cell refers to the cell currently providing services to the terminal. Neighboring cells are cells adjacent to the serving cell. The serving cell and neighboring cells can belong to the same network device or different network devices.

[0101] In this application, the SFN axis is used to map the frame number and subframe number corresponding to any time. The SFN axis of the serving cell refers to the candidate absolute time / absolute time of the epoch time, which is represented by the absolute time corresponding to the frame number 0 and subframe number 0 determined by the serving cell as the starting point.

[0102] For example, when a satellite base station sends SIB19 to a terminal, the terminal receives SIB19 in time T. ref The serving cell is cell 1, and the SFN axis corresponding to cell 1 is the SFN0 axis. The neighboring cell is cell 2, and the SFN axis corresponding to cell 2 is the SFN2 axis. SIB19 includes satellite ephemeris information for cell 1 and cell 2. The candidate absolute time for the epoch time in the satellite ephemeris information of cell 1 includes T. E1 The candidate absolute times for the epoch time in the satellite ephemeris information of cell 2 include T. E2 . Figure 5a For T ref and T E1 A schematic diagram, such as Figure 5a T shown E1 Tref It is the timestamp on the SFN0 axis. Figure 5b For T ref and T E2 A schematic diagram, such as Figure 5b T shown E2 T ref It is the timestamp on the SFN0 axis.

[0103] In this application, the candidate absolute time of the epoch time in the satellite ephemeris information refers to the time corresponding to the epoch time in each equivalent superframe. The absolute time of the epoch time in the satellite ephemeris information refers to the unique corresponding time selected from the times corresponding to the epoch time in each equivalent superframe.

[0104] In this application, an equivalent superframe refers to a time period of 10.24 seconds on the SFN axis and / or the absolute time axis. Each equivalent superframe can map any time period. The time in each equivalent superframe can map any time. There is a correspondence between the time in the equivalent superframe and the epoch time.

[0105] In this application, the time on the SFN axis and / or the absolute time axis can represent absolute time. The time on the SFN axis and / or the absolute time axis can be divided into "equivalent superframes," with each "equivalent superframe" ranging from 0 to 10.24 seconds. The epoch time in the satellite ephemeris information can be mapped to a time in each equivalent superframe.

[0106] Optionally, RRC signaling carrying satellite ephemeris information includes, but is not limited to, handover commands. When the RRC signaling is a handover command, the network device can send the satellite ephemeris information of the target cell's satellites to the terminal via the handover command. In this case, the SFN and subframe number indicated by the epoch time field in the satellite ephemeris information are timestamps on the target cell's SFN axis, and the time the network device sends the satellite ephemeris information is the timestamp on the serving cell's SFN axis. The target cell is the cell that takes over service from the serving cell to provide services to the terminal in the handover scenario.

[0107] In this application, the SFN axis of the target cell refers to the candidate absolute time / absolute time of the received epoch time, which is represented by the absolute time corresponding to the frame number 0 and subframe number 0 determined by the target cell as the starting point.

[0108] For example, the network device currently providing services to the terminal sends a handover command to the terminal. The serving cell is cell 1, and the SFN axis corresponding to cell 1 is the SFN0 axis. The time it takes for the terminal to receive the handover command is T. ref The target cell is cell 3, and the SFN axis corresponding to cell 3 is the SFN1 axis. The handover command includes the satellite ephemeris information of cell 3. The candidate absolute times for the epoch time in the satellite ephemeris information of cell 3 include T. E3 .Figure 6 For T ref and T E3 A schematic diagram, such as Figure 6 T shown ref It is the timestamp on the SFN0 axis, T E3 It is the timestamp on the SFN1 axis.

[0109] To estimate the future or past state of a satellite communication device relative to an epoch, it is necessary to determine the absolute time corresponding to the epoch. Then, based on the state of the satellite communication device at the absolute time of the epoch, the state of the satellite communication device at any given time can be estimated. Currently, the terminal selects a candidate absolute time from the candidate absolute times of the epoch in the satellite ephemeris information as the absolute time of the epoch in the satellite ephemeris information, according to the TS 38.331 protocol.

[0110] For example, when the satellite ephemeris information of a neighboring cell is carried in SIB19, the terminal can currently select the candidate absolute time with the smallest absolute time difference from the candidate absolute time of the epoch time in the satellite ephemeris information of the neighboring cell, according to the TS38.331 protocol, and use it as the absolute time of the epoch time in the satellite ephemeris information of the neighboring cell.

[0111] For example, when the satellite ephemeris information of the target cell carries a handover command, the terminal can currently select, according to the TS 38.331 protocol, the candidate absolute time with the smallest absolute time difference from the "absolute time when the terminal received the satellite ephemeris information" from the candidate absolute times of the epoch time in the satellite ephemeris information of the target cell, and use it as the absolute time of the epoch time in the satellite ephemeris information of the target cell.

[0112] In this application, the absolute time of the epoch can also be described as a relative value of the epoch, or the relative time between the epoch and the reception time of the satellite ephemeris information. The relative time between the epoch and the reception time of the satellite ephemeris information is not limited. It should be understood that the reception time of the satellite ephemeris information in this application can refer to the time when the terminal receives the satellite ephemeris information from the satellite communication device.

[0113] However, due to factors such as rapid changes in channel link characteristics and non-ideal terminal implementation, the absolute time of the terminal in determining the epoch time according to the TS38.331 protocol is inaccurate in "critical scenarios," causing errors in the state inference of satellite communication equipment, making it difficult to accurately receive and demodulate the signals of satellite communication equipment, and even leading to communication link interruption.

[0114] "Critical scenario" refers to the situation where, among the candidate absolute times of the epoch time in the satellite ephemeris information, there are two candidate absolute times with the smallest absolute value of the time difference between them and the "absolute time when the terminal receives the satellite ephemeris information".

[0115] In one example, among the candidate absolute times of the epoch time in the satellite ephemeris information of a neighboring cell, there are two candidate absolute times with the smallest absolute time difference from the "absolute time when the terminal receives the satellite ephemeris information". In this case, it is impossible to accurately select the absolute time of the epoch time in the satellite ephemeris information of the neighboring cell from these two candidate absolute times. There is a problem of selecting the wrong candidate absolute time as the absolute time of the epoch time in the satellite ephemeris information of the neighboring cell, which causes the terminal to be unable to accurately receive and demodulate the signal sent by the satellite communication equipment corresponding to the neighboring cell.

[0116] In another example, among the candidate absolute times of the epoch time in the satellite ephemeris information of the target cell, there are two candidate absolute times with the smallest absolute time difference from the "absolute time when the terminal receives the satellite ephemeris information". In this case, it is impossible to accurately select the absolute time of the epoch time in the satellite ephemeris information of the target cell from these two candidate absolute times. There is a problem of selecting the wrong candidate absolute time as the absolute time of the epoch time in the satellite ephemeris information of the target cell, which causes the terminal to fail to successfully access the target cell.

[0117] For example, the serving cell is cell 1, the neighboring cell is cell 2, and the SFN axis corresponding to cell 1 is the SFN0 axis. The satellite base station sends the satellite ephemeris information of cell 2 to the terminal via SIB19. After receiving SIB19, the terminal determines the absolute time of the epoch time in the satellite ephemeris information of cell 2 according to the TS38.331 protocol. Taking the time on the SFN0 axis as an example of representing absolute time, the time on SFN0 can be in units of "equivalent superframes". The time range of an "equivalent superframe" is 0 to 10.239s. Each equivalent superframe contains a candidate absolute time of the epoch time in the satellite ephemeris information of cell 2. Figure 7 This is a schematic diagram of the time distribution on SFN0. Figure 7 China T ref T is the absolute time for the terminal to receive SIB19. E1 T is the candidate absolute time for the epoch time in the satellite ephemeris information of cell 2 in "equivalent superframe 1". E2 For the candidate absolute time of the epoch time in the satellite ephemeris information of cell 2 in "equivalent superframe 2", T is the time when ref Located in the middle of "Equivalent Superframe 1", T ref With T E1 The absolute value of the time difference and T ref With T E2 If the absolute values ​​of the time differences are equal, then there exist two distances T.ref The most recent and equal candidate absolute times cause the terminal to be unable to obtain the data from T according to the TS 38.331 protocol (TS 38.331.6.3.2 section). E1 and T E2 The absolute time of the epoch in the satellite ephemeris information of cell 2 was accurately determined from T. E1 and T E2 If an incorrect candidate absolute time is selected as the absolute time of the epoch time in the satellite ephemeris information of cell 2, the terminal will not accurately determine the instantaneous state of the satellite communication equipment corresponding to cell 2. The parameters such as Doppler frequency offset and timing advance calculated based on the inaccurate instantaneous state will also be inaccurate, which will cause the terminal to be unable to accurately receive and demodulate the signals sent by the satellite communication equipment corresponding to the neighboring cell.

[0118] To address the issue of inaccurate determination of the absolute time of epoch times in satellite ephemeris information by terminals and to ensure the normal use of satellite ephemeris information, this application provides a communication method. The method includes: a first network device acquiring first information and sending the first information to a terminal device; the terminal device receiving the first information and determining the absolute time of the epoch time based on the first information. The first information indicates the relative relationship between the epoch time and a first time; the first time is the time when the satellite ephemeris information is received; the satellite ephemeris information carries the epoch time. The first network device is the network device currently providing services to the terminal device. The relative relationship described in this application can refer to a time relative relationship, that is, the relative chronological order of two times. Since there is only one relative relationship, the relative relationship between the epoch time indicated by the first information and the first time is unique. The terminal device can choose a unique candidate absolute time of the epoch time as the absolute time of the epoch time. Therefore, whether the first information directly or indirectly indicates the relative relationship between the epoch time and the first time, the terminal device can accurately determine the absolute time of the epoch time in the satellite ephemeris information, ensuring the normal use of the satellite ephemeris information.

[0119] The communication method provided in the embodiments of this application will be described below with reference to the accompanying drawings.

[0120] The technical methods of this application embodiment can be used in various communication systems in satellite communication scenarios. These communication systems can be third-generation partnership project (3GPP) communication systems, such as long-term evolution (LTE) systems, fifth-generation (5G) mobile communication systems, new radio (NR) systems, vehicle-to-everything (NRV2X) systems, LTE and 5G hybrid networking systems, wireless fidelity (WiFi) systems, device-to-device (D2D) communication systems, machine-to-machine (M2M) communication systems, integrated access and backhaul (IBA) communication systems, Internet of Things (IoT) systems, and other future communication systems. They can also be non-3GPP communication systems, without limitation.

[0121] The technical solutions of this application can be applied to various communication scenarios, such as one or more of the following communication scenarios: enhanced mobile broadband (eMBB), ultra-reliable low latency communication (URLLC), machine type communication (MTC), massive machine type communications (mMTC), D2D, V2X, and IoT communication scenarios.

[0122] Figure 8 This application provides a structural diagram of a communication system in a satellite communication scenario, as shown in the embodiments. Figure 8 As shown, the communication system may include a terminal device and a first network device. Figure 8 The first network device in China is currently... Figure 8 Network equipment that provides services to terminal devices. Figure 8 The first network device shown can be mounted or deployed on a flight platform, such as a low-altitude flight platform, a high-altitude flight platform, or a satellite. Or Figure 8The first network device shown can be located on the ground and connected to the flight platform via a gateway station. When the first network device is mounted on the flight platform, it moves synchronously with the flight platform, and its state remains consistent with that of the flight platform.

[0123] Figure 8 The communication system in the NTN scenario shown can be a satellite communication system. For example, it could be... Figure 9 The satellite communication system shown, such as Figure 9 As shown, the satellite communication system may include: a terminal, a first satellite base station, and a second satellite base station. The first and second satellite base stations are network devices mounted or deployed on a satellite to provide services to the terminal, and both can process data. The first satellite base station is the satellite base station currently providing services to the terminal. The first satellite base station includes a first cell and a second cell. The first cell is the cell currently providing services to the terminal. The second cell is a cell in the first satellite base station adjacent to the first cell. Optionally, the second cell can be a cell in the first satellite base station that takes over providing services to the terminal from the first cell. The second satellite base station is a satellite base station that can take over providing services to the terminal from the first satellite base station. The second satellite base station includes a third cell. The third cell can be a cell in the second satellite base station that takes over providing services to the terminal from the first cell. Optionally, the second satellite base station includes a fourth cell, which is a cell in the second satellite base station adjacent to the third cell.

[0124] The first network device involved in this application can be any device deployed in an access network capable of wireless communication with terminal devices. It can also be a chip or chip system that can be configured in the aforementioned device, or a logical node or logical module, or a function implemented in software. Its main responsibilities include air interface-side wireless physical control functions, resource scheduling, wireless resource management, quality of service management, data compression and encryption, wireless access control, and mobility management. Specifically, the first network device can be a device supporting wired access or a device supporting wireless access.

[0125] For example, the first network device may consist of one or more access network (AN) / radio access network (RAN) nodes. AN / RAN nodes may be various types of base stations, such as: satellite base stations, evolved Node Bs (gNBs), transmission reception points (TRPs), evolved Node Bs (eNBs), radio network controllers (RNCs), Node Bs (NBs), base station controllers (BSCs), base transceiver stations (BTSs), home base stations (e.g., home evolved Node Bs, or home Node Bs (HNBs), macro base stations, micro base stations, pico base stations, small cells, relay stations, balloon stations, unmanned aerial vehicle (UAV) stations, wireless backhaul nodes, baseband units (BBUs), or wireless fidelity (Wi-Fi) access points (APs), or grant nodes (G nodes) in satellite constellations, etc. It is understood that the first network device can be a ground-based device or a non-ground-based device (such as a satellite, drone, or high-altitude communication equipment). Furthermore, in communication systems employing different wireless access technologies, the names of network devices with base station functions may differ, and this application does not impose any restrictions on this.

[0126] In another example, the first network device may include a BBU and a remote radio unit (RRU). The BBU and RRU can be located in different locations; for example, the RRU can be moved remotely to a high-traffic area, while the BBU is located in a central equipment room. The BBU and RRU can also be located in the same equipment room. The BBU and RRU can also be different components within the same rack.

[0127] In another example, the first network device can also be a device that includes centralized unit (CU) nodes, distributed unit (DU) nodes, or both CU and DU nodes. For example, the network device can be logically divided into CU and DU, with some protocol layer functions centrally controlled by the CU, and the remaining part or all of the protocol layer functions distributed in the DU, which is centrally controlled by the CU. The CU and DU can be set up separately, or they can be included in the same network element, such as in a BBU. Furthermore, the centralized unit CU can also be divided into a control plane (CU-CP) and a user plane (CU-UP).

[0128] In another example, the first network device may also be a device that includes a radio unit (RU), or a device that includes a CU, a DU, and a RU. The RU may be included in a radio frequency device or radio frequency unit, such as an RRU, an active antenna unit (AAU), or a remote radio head (RRH).

[0129] It is understood that CU (or CU-CP and CU-UP), DU, or RU may have different names in different systems, but those skilled in the art will understand their meaning. For example, in an open radioaccess network (O-RAN) system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through a software module, a hardware module, or a combination of software and hardware modules.

[0130] The terminal equipment involved in this application may be a device with wireless transceiver capabilities or a chip or chip system that can be installed in the device, which allows users to access the network and is a device used to provide voice and / or data connectivity to users. The terminal equipment may also be referred to as terminal equipment, user equipment (UE), user unit (subscriber unit), terminal, mobile station (MS), or mobile terminal (MT), etc.

[0131] For example, a terminal device can be a mobile phone, a tablet computer, or a computer with wireless transceiver capabilities. A terminal device can also be a user station, mobile station, remote station, remote terminal device, mobile terminal device, user terminal device, wireless communication device, user agent, user device, cellular phone, cordless phone, session initiation protocol (SIP) phone, wireless local loop (WLL) station, personal digital assistant (PDA), handheld device with wireless communication capabilities, computing device, processing device connected to a wireless modem, in-vehicle device, wearable device, terminal device in the Internet of Things (IoT), home appliance, virtual reality (VR) terminal, augmented reality (AR) terminal, wireless terminal in industrial control, wireless terminal in autonomous driving, wireless terminal in telemedicine, wireless terminal in smart grid, wireless terminal in smart city, wireless terminal in smart home, vehicle with vehicle-to-vehicle (V2V) communication capabilities, intelligent connected vehicle, or unmanned aerial vehicle (UAV) communication. Unrestricted access is allowed for drones with U2U (to-UAV, U2U) communication capabilities, terminal devices in future networks, terminal devices in future evolved public land mobile networks (PLMNs), Wi-Fi stations (STAs), or terminal nodes (T-nodes) in satellite navigation systems. It is understood that the terminal device and the mobile user can be completely independent. All user-related information can be stored in a subscriber identity module (SIM) card, which can be used on the terminal device. The terminal device can interact with network-side devices by transmitting and / or receiving signals over the air interface.

[0132] Understandably, the above Figure 8 This is merely an illustrative diagram and does not constitute a limitation on the applicable scenarios of the technical solutions provided in this application. Those skilled in the art should understand that, in specific implementation processes, Figure 8 The communication system shown may also include more than Figure 8 Showing fewer devices, or, Figure 8 The communication system shown may also include other equipment, which can be determined according to specific needs. Figure 8The number of devices in the communication system shown is not limited.

[0133] Optional, Figure 8 The devices in the process, such as terminal devices and the first network device, can also be referred to as communication devices. They can be general-purpose devices or special-purpose devices. This application does not specifically limit them in this regard.

[0134] Optionally, this application Figure 8 The relevant functions of each device can be implemented by one device, multiple devices working together, or one or more functional modules within a single device. This application does not specifically limit this. It is understood that the above functions can be network elements in hardware devices, software functions running on dedicated hardware, a combination of hardware and software, or virtualization functions instantiated on a platform (e.g., a cloud platform).

[0135] The following is combined Figure 8 The communication system shown describes the communication method provided in the embodiments of this application. The actions, terms, etc. involved in the following embodiments can be referred to each other. The message names or parameter names in the messages between devices in each embodiment are just examples, and other names can be used in specific implementations. For example, "corresponding" in the following embodiments can be replaced by "associating", etc., and "sending" in the following embodiments can be replaced by "transmitting", etc.

[0136] Figure 10 This is a flowchart illustrating a communication method provided in an embodiment of this application, such as... Figure 10 As shown, it may include:

[0137] S1001: The first network device obtains the first information.

[0138] The first network device is the network device that currently provides services to the terminal device.

[0139] The first information is used to indicate the relative relationship between the epoch time and the first time.

[0140] The first time refers to the time when the terminal device receives the satellite ephemeris information. The satellite ephemeris information carries the epoch time.

[0141] In this application, the relative relationship between the epoch time indicated by the first information and the first time can characterize the unique relative relationship between the epoch time and the first time.

[0142] In this application, the first information can directly or indirectly indicate the relative relationship between the epoch time and the first time. For example, if the first information includes the correlation between the epoch time and the first time, it directly indicates the relative relationship between the epoch time and the first time. If the first information includes satellite ephemeris information carrying the epoch time, and the relative time relationship between the epoch time and the first time in the satellite ephemeris information satisfies preset constraints, it indirectly indicates the relative relationship between the epoch time and the first time.

[0143] In one example, the first information includes the relative relationship between the epoch time and the first time.

[0144] In this application, the satellite ephemeris information includes epoch time, so the first time can be the time when the terminal obtains the satellite ephemeris information. For example, in a handover scenario, the satellite ephemeris information can be carried in an RRC reconfiguration message, in which case the first time is the time when the terminal device obtains the RRC reconfiguration message. In a scenario where the terminal receives an SI, the satellite ephemeris information can be carried in SIB19, in which case the first time is the time when the terminal device obtains SIB19.

[0145] When the first information includes the relative relationship between the epoch time and the first time, the first network device acquiring the first information may include: the first network device acquiring the epoch time, determining the temporal relationship between the epoch time and the first time based on the chronological order of the epoch time and the first time, and further incorporating the temporal order of the epoch time and the first time into the first information. For details, please refer to [link to relevant documentation]. Figure 11 In the communication method shown, S1105, Figure 16 S1602 in the communication method shown.

[0146] When the first information includes the relative relationship between the epoch time and the first time, the method by which the first network device obtains the epoch time is not restricted. For example, in a handover scenario, the first network device can send a handover request to the second network device and receive the epoch time corresponding to the target cell from the second network device. For details, please refer to [link to relevant documentation]. Figure 11 The communication method is illustrated. In a scenario where the terminal receives the SI, if the first network device performs data processing, it can obtain the epoch time corresponding to the neighboring cells in its configuration information from its own configuration information, according to existing technology. If the first network device does not support data processing, it can obtain the epoch time corresponding to the neighboring cells in its configuration information from the ground equipment managing the relevant configuration information of the first network device via an inter-satellite link.

[0147] In this application, when the first information includes the relative relationship between the epoch time and the first time, the first information used to indicate the relative relationship between the epoch time and the first time may include: the first information used to indicate the chronological order of the epoch time and the first time, and / or, the first information used to indicate the absolute time difference between the epoch time and the first time.

[0148] The order of epoch time and first time can include one of the following: epoch time is earlier than first time, epoch time is later than / last than first time, or epoch time is equal to first time.

[0149] The chronological order of an epoch and a first time can be represented using a timeline. When representing an epoch and a first time using a timeline, an epoch earlier than the first time can be described as follows: the epoch is to the left of the first time, or the value of the epoch is less than the value of the first time. An epoch later than the first time can be described as follows: the epoch is to the right of the first time, or the value of the epoch is greater than the value of the first time. An epoch equal to the first time can be described as follows: the epoch and the first time are in the same position, or the value of the epoch is equal to the value of the first time.

[0150] The absolute time difference between the epoch time and the first time can include either the time difference between the epoch time and the first time, or the time difference between the first time and the epoch time.

[0151] In another example, the first piece of information is satellite ephemeris information. The satellite ephemeris information carries epoch times. Furthermore, the epoch times in the satellite ephemeris information are obtained according to preset constraints. These constraints are used to define the relative time relationship between the epoch times and the first time.

[0152] When the first information is satellite ephemeris information, the first network device acquiring the first information may include: the first network device acquiring an epoch time according to preset constraints, and further acquiring the position status information corresponding to that epoch time; and embedding the epoch time and the position status information corresponding to the epoch time into the satellite ephemeris information to obtain the first information. The position status information is used to indicate the position and / or velocity of the satellite communication device.

[0153] When the first piece of information is satellite ephemeris information, the satellite ephemeris information can be the satellite ephemeris information of the target cell or the satellite ephemeris information of neighboring cells. The target cell is the cell that takes over the service cell from the serving cell to provide service to the terminal device, and the serving cell is the cell currently providing service to the terminal device. Neighboring cells are cells adjacent to the serving cell.

[0154] When the satellite ephemeris information is the ephemeris information of the target cell, the preset constraint is that the epoch time is less than the first time. In this case, the first network device acquires the first information, which may include: the first network device using a time less than the first time, where the absolute value of the time difference from the first time is less than a preset value, as the epoch time; the first network device sending a first request message carrying the epoch time to the second network device; and responding to the first request message by receiving second information from the second network device. The second information includes the location status information corresponding to the epoch time of the target cell in the second network device. The epoch time and the location status information corresponding to the epoch time of the target cell are carried in the satellite ephemeris information to obtain the first information. For details, please refer to [link to relevant documentation]. Figure 14 The communication method shown.

[0155] When the satellite ephemeris information is the ephemeris information of a neighboring cell, the preset constraint is that the epoch time and the first time are points within the same preset time period, and the duration of the preset time period is less than or equal to a preset threshold. In this case, the first network device acquiring the first information may include: the first network device using any time within the preset time period as the epoch time, further acquiring the location status information corresponding to the epoch time of the neighboring cell, and embedding the epoch time and the location status information corresponding to the epoch time of the neighboring cell into the satellite ephemeris information to obtain the first information. For details, please refer to [link to relevant documentation]. Figure 17 The communication method shown.

[0156] The preset time period has a duration less than or equal to a preset threshold. 0 is less than the preset threshold, and the preset threshold is less than or equal to 5.12 seconds. The start time of the preset time period can be any time and is not restricted.

[0157] Optionally, in a handover scenario, the first information can be carried in the handover confirmation. In a scenario where the terminal receives SIB19, the first information can be carried in SIB19.

[0158] S1002: The first network device sends first information to the terminal device, and the terminal device receives the first information from the first network device.

[0159] Specifically, the first network device sends first information to the terminal device. If the first information includes the relative relationship between epoch time and first time, this includes the first network device sending both the first information and satellite ephemeris information to the terminal. If the first information is satellite ephemeris information, this includes the first network device sending the first information to the terminal.

[0160] Similarly, the terminal device receives first information from the first network device. If the first information includes the relative relationship between epoch time and first time, this includes the terminal receiving both the first information from the first network device and satellite ephemeris information. If the first information includes satellite ephemeris information, this includes the terminal receiving the first information from the first network device.

[0161] This application does not limit the method by which the first network device sends the first information to the terminal device. When the first information includes satellite ephemeris information, the first network device may send the first information to the terminal device via broadcast, or the first network device may send the first information to the terminal device via RRC signaling.

[0162] S1003: The terminal device determines the absolute time of the epoch based on the first information.

[0163] In one example, when the first information is used to indicate the chronological order of the epoch time and the first time, the terminal device selects a candidate absolute time from the candidate absolute times of the epoch time as the absolute time of the epoch time. The chronological order of a candidate absolute time and the first time satisfies the chronological order of the epoch time and the first time indicated by the first information. See S1108 for a detailed description.

[0164] Among them, the candidate absolute time of the epoch time includes the epoch time in each equivalent superframe.

[0165] The equivalent superframe duration is a preset value. Optionally, this preset value is 10.24s.

[0166] In another example, when the first information is used to indicate the absolute time difference between the epoch time and the first time, the terminal device selects a candidate absolute time from the candidate absolute times of the epoch time as the absolute time of the epoch time; the absolute value of the time difference between a candidate absolute time and "the time of the first time plus the absolute time difference indicated by the first information" is less than a preset threshold. See S1108 for a detailed description.

[0167] In another example, when the first information is satellite ephemeris information, the terminal device selects a candidate absolute time from the candidate absolute times of the epoch time carried by the satellite ephemeris information, and uses it as the absolute time of the epoch time. The absolute value of the time difference between a candidate absolute time and the first time is less than a preset threshold.

[0168] In this application, the value of the preset threshold is not limited. If the absolute time difference between a candidate absolute time and "the time difference between the first time and the absolute time difference indicated by the first information" is less than the preset threshold, it indicates that the absolute value of the time difference between a candidate absolute time and "the time difference between the first time and the absolute time difference indicated by the first information" is less than the absolute value of the time difference between any candidate absolute time in the candidate absolute times of the epoch and "the time difference between the first time and the absolute time difference indicated by the first information". Alternatively, if the absolute value of the time difference between a candidate absolute time and the first time is less than the preset threshold, it indicates that the absolute value of the time difference between a candidate absolute time and the first time is less than the absolute value of the time difference between any candidate absolute time in the "candidate absolute times of the target epoch" and the first time.

[0169] When absolute time is represented by time on a timeline, if the absolute time difference between a candidate absolute time and "the time difference between the first time and the absolute time difference indicated by the first information" is less than a preset threshold, then the position of the candidate absolute time on the timeline is closest to the position of "the time difference between the first time and the absolute time difference indicated by the first information" on the timeline. Alternatively, if the absolute value of the time difference between a candidate absolute time and the first time is less than a preset threshold, then the position of the candidate absolute time on the timeline is closest to the position of the first time on the timeline.

[0170] based on Figure 10 The communication method shown involves a first network device acquiring first information indicating the relative relationship between an epoch time and a first time, and sending the first information to a terminal device. When the first information includes the relative relationship between the epoch time and the first time, the terminal can accurately determine the absolute time of an epoch from the candidate absolute times of the epoch time based on the indication of the first information, ensuring that the satellite ephemeris information of the epoch time can be used normally. Alternatively, when the first information includes satellite ephemeris information, the candidate absolute time with the smallest absolute time difference from the "absolute time of the time the terminal receives the satellite ephemeris information" among the candidate absolute times of the epoch time in the satellite ephemeris information is unique. Therefore, no "critical scenario" will occur during the terminal's determination of the absolute time of the epoch time, allowing the terminal to accurately determine the absolute time of the epoch time and ensuring that the satellite ephemeris information can be used normally.

[0171] The following is combined Figure 9The satellite communication system shown, in a handover scenario, has a first network device as a first satellite base station, a second network device as a second satellite base station, and a terminal device as a terminal example. The first satellite base station is the current satellite base station providing service to the terminal, and it includes a first cell, specifically the cell currently providing service to the terminal. The second satellite base station is the satellite base station that takes over providing service to the terminal from the first satellite base station. The second satellite base station includes a third cell, specifically the cell in the second satellite base station that takes over providing service to the terminal from the first cell in the first satellite base station. (Combined...) Figure 11 or Figure 14 right Figure 10 The communication method shown will be introduced.

[0172] Figure 11 This is a flowchart illustrating a communication method provided in an embodiment of this application, such as... Figure 11 As shown, the method may include:

[0173] S1101: The terminal sends a handover request message to the first satellite base station, and the first satellite base station receives the handover request message.

[0174] The handover request message can request a switch to a satellite base station providing service to the terminal or a switch to the cell currently providing service to the terminal. The handover request message can be a handover request signaling message as defined in the wireless communication protocol.

[0175] S1102: In response to the handover request message, the first satellite base station sends a handover request to the second satellite base station, and the second satellite base station receives the handover request.

[0176] The process of the first satellite base station sending a handover request to the second satellite base station may include: the first satellite base station determining that the second satellite base station is the satellite base station that will take over the service for the terminal, and sending a handover request to the second satellite base station.

[0177] The handover request is used to request the allocation of resources for the terminal device.

[0178] It should be understood that the first satellite base station can send a handover request to the second satellite base station directly or indirectly. For example, if there is an available inter-satellite link between the first and second satellite base stations, the first satellite base station can send a handover request to the second satellite base station through the inter-satellite link. Alternatively, if there is no available inter-satellite link between the first and second satellite base stations, the first satellite base station can send a handover request to the second satellite base station through other equipment (e.g., core network equipment). An inter-satellite link refers to a link used for direct communication between satellite base stations, also known as an inter-satellite link or cross-link, and can be a wireless interface or an optical interface.

[0179] S1103: In response to the handover request, the second satellite base station performs access control.

[0180] Specifically, the second satellite base station can determine which resources to allocate to the terminal based on factors such as the terminal's capabilities and network load. For example, the second satellite base station may designate a third cell within its network as the cell to take over service from the first cell, thus enabling the second satellite base station to provide service to the terminal in place of the first satellite base station.

[0181] S1104: The second satellite base station sends a handover confirmation, and the first satellite base station receives the handover confirmation.

[0182] The handover request acknowledgement is used to instruct the second satellite base station to allow the terminal to access the network.

[0183] The handover confirmation may include configuration information provided to the terminal by the second satellite base station and / or the third cell within the second satellite base station. This could include, for example, the identifier of the third cell and its satellite ephemeris information. The identifier of the third cell identifies the third cell. The satellite ephemeris information of the third cell within the second satellite base station may include: the epoch time corresponding to the third cell in the second satellite base station and the location status information corresponding to that epoch time. The satellite ephemeris information of the third cell in the second satellite base station can characterize the state of the second satellite base station at the time the epoch time arrives, and that the wireless coverage area provided to the terminal by the second satellite base station in that state is the third cell.

[0184] It should be understood that the second satellite base station can send handover confirmations directly or indirectly to the first satellite base station. For example, if there is an available inter-satellite link between the second and first satellite base stations, the second satellite base station can send handover confirmations to the first satellite base station through the inter-satellite link. Alternatively, if the interface between the first and second satellite base stations is heavily loaded, the second satellite base station can send handover confirmations to the first satellite base station through other equipment (e.g., core network equipment).

[0185] S1105: The first satellite base station determines the relative relationship between the epoch time corresponding to the third cell in the second satellite base station and the first time.

[0186] The first time refers to the time when the terminal receives the RRC reconfiguration message. A description of the RRC reconfiguration message is provided in S1106 and will not be repeated here.

[0187] In this application, the time when the first satellite base station sends the RRC reconfiguration message to the terminal is consistent with the time when the terminal receives the RRC reconfiguration message.

[0188] The relative relationship between the epoch time corresponding to the third cell in the second satellite base station and the first time may include: the order of the epoch time corresponding to the third cell in the second satellite base station and the first time, or the absolute time difference between the epoch time corresponding to the third cell in the second satellite base station and the first time.

[0189] The order of the epoch time corresponding to the third cell in the second satellite base station and the first time can include any one of the following: the epoch time corresponding to the third cell in the second satellite base station is earlier than the first time, the epoch time corresponding to the third cell in the second satellite base station is later than the first time, or the epoch time corresponding to the third cell in the second satellite base station is equal to the first time.

[0190] When the epoch time corresponding to the third cell in the second satellite base station is represented by the time axis compared with the first time, the epoch time corresponding to the third cell in the second satellite base station being earlier than the first time can be alternatively described as: the epoch time corresponding to the third cell in the second satellite base station is to the left of the first time, or the value of the epoch time corresponding to the third cell in the second satellite base station is less than the value of the first time.

[0191] When the epoch time corresponding to the third cell in the second satellite base station is characterized by the time axis and the first time, the epoch time corresponding to the third cell in the second satellite base station being later than the first time can be alternatively described as: the epoch time corresponding to the third cell in the second satellite base station is to the right of the first time, or the value of the epoch time corresponding to the third cell in the second satellite base station is greater than the value of the first time.

[0192] When the epoch time corresponding to the third cell in the second satellite base station is represented by the time axis and the first time, the equality of the epoch time corresponding to the third cell in the second satellite base station and the first time can be alternatively described as: the epoch time corresponding to the third cell in the second satellite base station and the first time are at the same position, or the value of the epoch time corresponding to the third cell in the second satellite base station and the value of the first time are equal.

[0193] The absolute time difference between the epoch time corresponding to the third cell in the second satellite base station and the first time can include either the epoch time corresponding to the third cell in the second satellite base station minus the time difference of the first time, or the time difference between the first time and the epoch time corresponding to the third cell in the second satellite base station.

[0194] S1106: The first satellite base station sends an RRC reconfiguration message to the terminal, and the terminal receives the RRC reconfiguration message.

[0195] The RRC reconfiguration message is used to trigger the terminal to perform a cell handover, causing the terminal to switch from the first cell to the third cell. The RRC reconfiguration message may include satellite ephemeris information of the third cell in the second satellite base station, as well as first information.

[0196] The first information may include the relative relationship between the epoch time corresponding to the third cell in the second satellite base station and the first time. In this case, the first information can be used to indicate the relative relationship between the epoch time corresponding to the third cell in the second satellite base station and the first time, or the first information can be used to indicate the absolute time difference between the epoch time corresponding to the third cell in the second satellite base station and the first time. The relevant descriptions of the relative relationship between the epoch time corresponding to the third cell in the second satellite base station and the first time, and the absolute time difference between the epoch time corresponding to the third cell in the second satellite base station and the first time, are given in S1105 and will not be repeated here.

[0197] Optionally, the RRC reconfiguration message can be called a switching command.

[0198] S1107: The terminal performs downlink synchronization with the second satellite base station.

[0199] The terminal's downlink synchronization with the second satellite base station may include: the terminal completing downlink synchronization with the second satellite base station based on RRC reconfiguration messages, through processes such as cell search and desystem message decomposition.

[0200] After the terminal completes downlink synchronization with the second satellite base station, the downlink synchronization time between the terminal and the second satellite base station can be obtained.

[0201] It should be understood that the completion of downlink synchronization between the terminal and the second satellite base station is the starting point for establishing communication between the terminal and the second satellite base station. Specifically, the terminal's execution of downlink synchronization with the second satellite base station is existing technology and will not be elaborated here.

[0202] S1108: The terminal determines the absolute time of the epoch time corresponding to the third cell in the second satellite base station based on the satellite ephemeris information of the third cell in the second satellite base station and the first information.

[0203] Specifically, the terminal selects a candidate absolute time from the candidate absolute times of the epoch time corresponding to the third cell in the second satellite base station as the absolute time of the epoch time corresponding to the third cell in the second satellite base station. The relationship between this candidate absolute time and the first time satisfies the relative relationship between the epoch time corresponding to the third cell in the second satellite base station and the first time indicated by the first information.

[0204] If, among the candidate absolute times for the epoch time corresponding to the third cell in the second satellite base station, there exists at least one candidate absolute time whose relationship with the first time satisfies the "relative relationship between the epoch time corresponding to the third cell in the second satellite base station indicated by the first information and the first time," then one of the candidate absolute times is selected as the absolute time for the epoch time corresponding to the third cell in the second satellite base station. The absolute value of the time difference between this candidate absolute time and the absolute time of the first time is less than the absolute value of the time difference between the absolute time of "all other candidate absolute times among the at least one candidate absolute time" and the absolute time of the first time.

[0205] Using time on a timeline to represent absolute time, and taking the order of the epoch time corresponding to the third cell in the second satellite base station and the first time as an example, the terminal determines the absolute time of the epoch time corresponding to the third cell in the second satellite base station based on the satellite ephemeris information of the third cell in the second satellite base station and the first information. This can include: the terminal determining the time of the first time on the timeline, the candidate times of the epoch time corresponding to the third cell in the second satellite base station on the timeline, and selecting one candidate time from the candidate times of the epoch time corresponding to the third cell in the second satellite base station as the time of the epoch time corresponding to the third cell in the second satellite base station on the timeline. The order of this candidate time and the first time on the timeline satisfies the order of the epoch time corresponding to the third cell in the second satellite base station and the first time indicated by the first information.

[0206] In this application, during handover scenarios, the time axis can be an absolute time axis or the SFN axis of the target cell (third cell). In other scenarios besides handover, such as when the terminal receives SIB19, the time axis can be an absolute time axis or the SFN axis of the serving cell (first cell).

[0207] For example, assuming the time axis is the SFN1 axis of the target cell (third cell) in the handover scenario, the time on the SFN1 axis is used to represent absolute time, and the time on the SFN1 axis is in units of "equivalent superframe". The first information indicates that the epoch time corresponding to the third cell in the second satellite base station is earlier than the first time. Figure 12 This is a schematic diagram of the time distribution on the SFN1 axis. The terminal determines the first time on the SFN1 axis as... Figure 12 T in r ′ ef The candidate times for the epoch time of the third cell in the second satellite base station on the SFN1 axis include T. E1 and T E2Because the first information indicates that the epoch time corresponding to the third cell in the second satellite base station is earlier than the first time, the epoch time corresponding to the third cell in the second satellite base station should be within the T time frame on the SFN1 axis. r ′ ef The left side. For example... Figure 12 As shown, T E1 In T r ′ ef On the left side, T E2 In T r ′ ef Therefore, the absolute time of the epoch time corresponding to the third cell in the second satellite base station is T on the SFN1 axis. E1 .

[0208] If, among the candidate times of the epoch time corresponding to the third cell in the second satellite base station on the time axis, there exists at least one candidate time whose order with the first time satisfies the condition that "the epoch time of the third cell in the second satellite base station indicated by the first information is in the order with the first time", then the candidate time that is closest to the first time on the time axis is selected as the time of the epoch time corresponding to the third cell in the second satellite base station on the time axis.

[0209] Using time on a timeline to represent absolute time, taking the absolute time difference between the epoch time corresponding to the third cell in the second satellite base station and the first time as an example, the terminal determining the absolute time of the epoch time corresponding to the third cell in the second satellite base station may include: the terminal determining the time of the first time on the timeline, candidate times of the epoch time corresponding to the third cell in the second satellite base station on the timeline, and the first information; and selecting a candidate time from the candidate times of the epoch time corresponding to the third cell in the second satellite base station as the time of the epoch time corresponding to the third cell in the second satellite base station on the timeline. The absolute value of the time difference between this candidate time and "the sum of the time of the first time on the timeline and the time of the absolute time difference indicated by the first information on the timeline" is minimized.

[0210] For example, assuming the time axis is the SFN1 axis corresponding to the target cell in the handover scenario, the time on the SFN1 axis is used to represent absolute time, and the time on the SFN1 axis is in units of "equivalent superframes". The first information indicates that the difference between the epoch time corresponding to the third cell in the second satellite base station and the first time is △T, and △T<0. Figure 13 This is a schematic diagram of the time distribution on the SFN1 axis. The terminal determines the first time on the SFN1 axis as... Figure 13 T in r ′ ef The candidate times for the epoch time of the third cell in the second satellite base station on the SFN1 axis include T. E1 and TE2 Because the difference between the epoch time corresponding to the third cell in the second satellite base station and the first time, as indicated by the first information, is ΔT, and ΔT < 0, the time of the epoch time corresponding to the third cell in the second satellite base station on the SFN1 axis is T. E1 and T E2 The closest to T sum Time. T sum T on the SFN1 axis r ′ ef The time taken to add the sum of ΔT. For example... Figure 13 As shown, T E1 With T sum The absolute time difference between them |T E1 -T sum | Less than T E2 With T sum The absolute time difference between them |T E2 -T sum Therefore, the absolute time of the epoch time corresponding to the third cell in the second satellite base station is T on the SFN1 axis. E1 .

[0211] In this application, the absolute time of the first time can be determined based on the downlink synchronization time and the time difference between the downlink synchronization time and the first time. Specifically, the absolute time of the first time is equal to the absolute time of the downlink synchronization time minus the absolute time difference between the downlink synchronization time and the first time.

[0212] For example, the time on the SFN1 axis represents absolute time, and the SFN1 axis is the SFN axis of the target cell (third cell). In this case, the absolute time of the first time is the time of the first time on the SFN1 axis, the absolute time of the downlink synchronization time is the time of the downlink synchronization time on the SFN1 axis, and the absolute time of "the time difference between the downlink synchronization time and the first time" is the time of "the time difference between the downlink synchronization time on the absolute time axis and the time difference between the first time on the absolute time axis" on the SFN1 axis. The terminal can determine the absolute time of the first time according to formula (1):

[0213] (SFN1)T r ′ ef =(SFN1)T sync -(SFN1)[(abs)T sync -(abs)T ref (1)

[0214] In formula (1), (SFN1)T r ′ ef (SFN1)T represents the time on the SFN1 axis at the first instant. sync(abs)T represents the downlink synchronization time on the SFN1 axis. sync (abs)T represents the downlink synchronization time on the absolute time axis. ref This indicates the first instant on the absolute timeline. (SFN1)[(abs)T sync -(abs)T ref ] represents [(abs)T sync -(abs)T ref The time on the SFN1 axis is the time difference between the downlink synchronization time on the absolute time axis and the first time on the absolute time axis.

[0215] S1109: The terminal has completed the switch from the first satellite base station to the second satellite base station.

[0216] The process of a terminal switching from the first satellite base station to the second satellite base station may include: the terminal calculating relevant parameters such as Doppler frequency offset, timing advance (TA), and propagation delay between the terminal and the second satellite base station based on the absolute time of the epoch time corresponding to the third cell in the second satellite base station and the location status information corresponding to the epoch time of the third cell in the second satellite base station, so that the terminal can successfully access the second satellite base station and switch from the first cell in the first satellite base station to the third cell in the second satellite base station.

[0217] S1110: The terminal sends an RRC reconfiguration complete message to the second satellite base station, and the second satellite base station receives the RRC reconfiguration complete message.

[0218] The RRC reconfiguration complete message indicates that the terminal has completed cell handover.

[0219] based on Figure 11The communication method shown allows the terminal to obtain the absolute time of the third cell in the second satellite base station during handover scenarios, based on the relative relationship between the epoch time of the third cell and the first time. This adds new information (the relative relationship between the epoch time of the third cell and the first time) to the terminal's determination of the absolute time of the cell in the second satellite base station during handover scenarios. This allows the terminal to obtain the absolute time of the third cell based on the new information, avoiding the problem of inaccurate determination of the absolute time of the third cell and ensuring the usability of the satellite ephemeris information of the second satellite base station. Simultaneously, the terminal does not introduce "state rollback" latency. That is, it avoids the latency of repeatedly determining the absolute time of the cell in the second satellite base station after initially determining it to be inaccurate.

[0220] Figure 11 The communication method shown provides a first information in a handover scenario, including the relative relationship between epoch time and first time. This allows the terminal to accurately obtain the absolute time of the epoch time corresponding to the third cell in the second satellite base station based on the first information, ensuring that the satellite ephemeris information of the second satellite base station can be used normally. The following example... Figure 14 Taking the communication method shown as an example, a communication method is provided in which the first information in a switching scenario is satellite ephemeris information, so that the terminal can accurately obtain the absolute time of the epoch time corresponding to the third cell in the second satellite base station based on the first information, thereby ensuring that the satellite ephemeris information of the second satellite base station is usable.

[0221] Figure 14 This is a flowchart illustrating a communication method provided in an embodiment of this application, such as... Figure 14 As shown, the method may include:

[0222] S1401: The terminal sends a handover request message to the first satellite base station, and the first satellite base station receives the handover request message.

[0223] For details regarding S1401, please refer to the relevant descriptions of S1101; they will not be repeated here.

[0224] S1402: The first satellite base station obtains the epoch time corresponding to the third cell in the second satellite base station according to the preset constraints corresponding to the target cell.

[0225] The preset constraints for the target cell are: the epoch time is less than the first time, and the absolute value of the time difference between the epoch time and the first time is less than a preset value.

[0226] In this application, the preset constraints corresponding to the target cell refer to the preset constraints under the satellite ephemeris information of the target cell.

[0227] Specifically, the time that is less than or equal to the first time and the absolute value of the time difference with the first time is less than a preset value will be used as the epoch time of the third cell in the second satellite base station.

[0228] The preset value can range from 0s to 5.12s. For the first time reference, please refer to the relevant description in S1105; it will not be repeated here.

[0229] S1403: In response to the handover request message, the first satellite base station sends a handover request to the second satellite base station, and the second satellite base station receives the handover request.

[0230] The description of the handover request sent from the first satellite base station to the second satellite base station can be found in S1102, and will not be repeated here.

[0231] S1404: The first satellite base station sends a first request message to the second satellite base station, and the second satellite base station receives the first request message.

[0232] The first request message is used to request the location status information corresponding to the epoch time. The first request message includes the epoch time corresponding to the third cell in the second satellite base station.

[0233] It should be noted that steps S1403-S1404 described above are merely illustrative descriptions of the communication method flow. The execution order of steps S1403 and S1404 is not limited. For example, step S1403 may be executed before step S1404; or step S1403 may be executed after step S1404; or step S1403 and step S1404 may be executed simultaneously.

[0234] S1405: In response to the handover request, the second satellite base station performs access control.

[0235] For details regarding S1405, please refer to the relevant descriptions of S1103; they will not be repeated here.

[0236] S1406: The second satellite base station sends the second information to the first satellite base station, and the first satellite base station receives the second information.

[0237] The second information includes the location status information corresponding to the epoch time of the third cell in the second satellite base station.

[0238] S1407: The second satellite base station sends a handover confirmation to the first satellite base station, and the first satellite base station receives the handover confirmation.

[0239] The handover confirmation may include configuration information provided to the terminal by the second satellite base station and / or the third cell. For example, the identifier of the third cell.

[0240] It should be noted that steps S1406-S1407 described above are merely illustrative descriptions of the communication method flow. The execution order of steps S1406 and S1407 is not limited. For example, step S1406 may be executed before step S1407; or step S1406 may be executed after step S1407; or step S1406 and step S1407 may be executed simultaneously.

[0241] S1408: The first satellite base station sends an RRC reconfiguration message to the terminal, and the terminal receives the RRC reconfiguration message.

[0242] The RRC reconfiguration message may include: the target epoch time corresponding to the third cell in the second satellite base station and the location status information corresponding to the target epoch time of the third cell in the second satellite base station.

[0243] S1409: The terminal performs downlink synchronization with the second satellite base station.

[0244] For details regarding S1409, please refer to the relevant descriptions in S1107; they will not be repeated here.

[0245] S1410: The terminal determines the absolute time of the epoch time corresponding to the third cell in the second satellite base station.

[0246] The terminal determines the absolute time of the target epoch time corresponding to the third cell in the second satellite base station by: selecting a candidate absolute time from the candidate absolute times of the epoch time corresponding to the third cell in the second satellite base station as the absolute time of the epoch time corresponding to the third cell in the second satellite base station. The absolute value of the time difference between a candidate absolute time and the first time is less than a preset threshold.

[0247] The preset threshold can be found in the relevant description in S1003, and will not be repeated here.

[0248] For example, suppose the preset value in the new protocol constraint in the handover scenario is 5.12s, and the time axis is the SFN1 axis of the target cell (third cell) in the handover scenario. The time on the SFN1 axis is used to represent absolute time, and the time on the SFN1 axis is in the unit of "equivalent superframe". Figure 15 This is a schematic diagram of the time distribution on the SFN1 axis. The terminal determines the first time on the SFN1 axis as... Figure 15 T inr ′ ef That is, the absolute time of the first moment is T. r ′ ef The candidate times for the epoch time of the third cell in the second satellite base station on the SFN1 axis include T. E1 T E2 T E3 and T E4 The new protocol constraints in the handover scenario include: the epoch time corresponding to the third cell in the second satellite base station is less than the first time, and the absolute time difference between the epoch time corresponding to the third cell in the second satellite base station and the first time is less than or equal to 5.12 seconds. Figure 15 As shown, T E1 Located in T r ′ ef The left side, i.e., T E1 Less than T r ′ ef And T E1 With T r ′ ef The absolute time difference between them |T E1 -T r ′ ef | Greater than 10.239s. T E2 Located in T r ′ ef The left side, i.e., T E2 Less than T r ′ ef And T E2 With T r ′ ef The absolute time difference between them |T E2 -T r ′ ef | equals 5.1195s, and 5.1195s is less than 5.12s. T E3 and T E4 In T r ′ ef The right side, i.e., T E3 With T E4 Both are greater than T r ′ ef Therefore, the absolute time of the epoch time corresponding to the third cell in the second satellite base station is T on the SFN1 axis. E2 .

[0249] S1411: The terminal has completed the switch from the first satellite base station to the second satellite base station.

[0250] S1412: The terminal sends an RRC reconfiguration complete message to the second satellite base station, and the second satellite base station receives the RRC reconfiguration complete message.

[0251] For the relevant descriptions of S1411-S1412, please refer to the relevant descriptions of S1109-S1110, which will not be repeated here.

[0252] based on Figure 14 The communication method shown, in a handover scenario, involves the first satellite base station determining the epoch time corresponding to the third cell in the second satellite base station based on preset constraints corresponding to the target cell, and sending this epoch time to the terminal in an RRC reconfiguration message. At this time, among the candidate absolute times of the epoch time corresponding to the third cell in the second satellite base station, the candidate absolute time with the smallest absolute difference from the "absolute time when the terminal receives the RRC reconfiguration message" is unique. Therefore, during the process of the terminal determining the absolute time of the epoch time corresponding to the third cell in the second satellite base station, no "critical scenario" occurs, and the absolute time of the epoch time corresponding to the third cell in the second satellite base station can be accurately determined, ensuring that the satellite ephemeris information of the second satellite base station is available, and achieving a successful handover from the first satellite base station to the second satellite base station. Simultaneously, the terminal does not introduce "state rollback" latency.

[0253] The following is combined Figure 9 The satellite communication system shown takes a terminal receiving SIB19 signals from a first satellite base station as an example. The first satellite base station supports data processing and includes a first cell and a second cell. The first cell is the cell within the first satellite base station currently providing service to the terminal. The second cell is the cell within the first satellite base station adjacent to the first cell. (Combined...) Figure 16 right Figure 10 The communication method shown will be introduced.

[0254] Figure 16 This is a flowchart illustrating a communication method provided in an embodiment of this application, such as... Figure 16 As shown, the method may include:

[0255] S1601: The first satellite base station obtains the satellite ephemeris information of the second cell in the first satellite base station.

[0256] The first satellite base station can obtain the satellite ephemeris information of the second cell in the first satellite base station from the module that manages the relevant configuration information of the first satellite base station, according to existing technology. The satellite ephemeris information of the second cell in the first satellite base station may include the epoch time and location status information corresponding to the epoch time of the second cell in the first satellite base station.

[0257] The satellite ephemeris information of the second cell in the first satellite base station can characterize the state of the first satellite base station when the epoch time arrives, and the wireless coverage area provided by the first satellite base station to the terminal in this state is the second cell.

[0258] S1602: The first satellite base station determines the relative relationship between the epoch time corresponding to the second cell in the first satellite base station and the first time.

[0259] The first time refers to the time when the terminal receives SIB19. SIB19 can be found in the relevant description in S1603 and will not be repeated here.

[0260] The relative relationship between the epoch time corresponding to the second cell in the first satellite base station and the first time may include: the order of the epoch time corresponding to the second cell in the first satellite base station and the first time, or the absolute time difference between the epoch time corresponding to the second cell in the first satellite base station and the first time.

[0261] The order of the epoch time corresponding to the second cell in the first satellite base station and the first time can include any one of the following: the epoch time corresponding to the second cell in the first satellite base station is earlier than the first time, the epoch time corresponding to the second cell in the first satellite base station is later than the first time, or the epoch time corresponding to the second cell in the first satellite base station is equal to the first time.

[0262] When the epoch time corresponding to the second cell in the first satellite base station is represented by the time axis and the first time, the epoch time corresponding to the second cell in the first satellite base station being earlier than the first time can be alternatively described as: the epoch time corresponding to the second cell in the first satellite base station is to the left of the first time, or the value of the epoch time corresponding to the second cell in the first satellite base station is less than the value of the first time.

[0263] When the epoch time corresponding to the second cell in the first satellite base station is represented by the time axis and the first time, the epoch time corresponding to the second cell in the first satellite base station being later than the first time can be alternatively described as: the epoch time corresponding to the second cell in the first satellite base station is to the right of the first time, or the value of the epoch time corresponding to the second cell in the first satellite base station is greater than the value of the first time.

[0264] When the epoch time corresponding to the second cell in the first satellite base station is represented by the time axis and the first time, the equality of the epoch time corresponding to the second cell in the first satellite base station and the first time can be alternatively described as: the epoch time corresponding to the second cell in the first satellite base station and the first time are at the same position, or the value of the epoch time corresponding to the second cell in the first satellite base station and the value of the first time are equal.

[0265] The absolute time difference between the epoch time corresponding to the second cell in the first satellite base station and the first time can include either the time difference between the epoch time corresponding to the second cell in the first satellite base station and the first time, or the time difference between the first time and the epoch time corresponding to the second cell in the first satellite base station.

[0266] S1603: The first satellite base station sends SIB19 to the terminal, and the terminal receives SIB19.

[0267] SIB19 is used to indicate frequency configurations and priorities between different system cells, ensuring network coordination and efficient resource allocation.

[0268] SIB19 may include satellite ephemeris information of the second cell in the first satellite base station and first information.

[0269] The first information may include the relative relationship between the epoch time corresponding to the second cell in the first satellite base station and the first time. In this case, the first information can be used to indicate the relative relationship between the epoch time corresponding to the second cell in the first satellite base station and the first time. The description of the relative relationship between the epoch time corresponding to the second cell in the first satellite base station and the first time is given in S1602 and will not be repeated here.

[0270] Sending SIB19 from the first satellite base station to the terminal may include: the first satellite base station may periodically send SIB19 to the terminal in a broadcast manner at a period of any length of time.

[0271] S1604: Terminal resolution of SIB19.

[0272] The terminal parses SIB19 to obtain the satellite ephemeris information and first information of the second cell in the first satellite base station within SIB19. Terminal parsing of SIB19 is existing technology and will not be elaborated upon here.

[0273] It should be understood that the downlink synchronization with the first satellite base station has been completed before the terminal resolves SIB19. Therefore, the downlink synchronization time between the terminal and the first satellite base station can be obtained before the terminal resolves SIB19.

[0274] S1605: The terminal determines the absolute time of the epoch time corresponding to the second cell in the first satellite base station based on the satellite ephemeris information of the second cell in the first satellite base station and the first information.

[0275] Specifically, the terminal selects a candidate absolute time from the candidate absolute times of the epoch time corresponding to the second cell in the first satellite base station as the absolute time of the epoch time corresponding to the second cell in the first satellite base station. The relationship between this candidate absolute time and the first time satisfies the "relative relationship between the epoch time corresponding to the second cell in the first satellite base station indicated by the first information and the first time".

[0276] If, among the candidate absolute times for the epoch time corresponding to the second cell in the first satellite base station, there exists at least one candidate absolute time whose relationship with the first time satisfies the "relative relationship between the epoch time corresponding to the second cell in the first satellite base station indicated by the first information and the first time," then one of the candidate absolute times is selected as the absolute time for the epoch time corresponding to the second cell in the first satellite base station. The absolute value of the time difference between this candidate absolute time and the absolute time of the first time is less than the absolute value of the time difference between the absolute time of "all other candidate absolute times among the at least one candidate absolute time" and the absolute time of the first time.

[0277] Using time on a timeline to represent absolute time, and taking the order of the epoch time corresponding to the second cell in the first satellite base station and the first time as an example, the terminal determines the absolute time of the epoch time corresponding to the second cell in the first satellite base station based on the satellite ephemeris information of the second cell in the first satellite base station and the first information. This can include: the terminal determining the time of the first time on the timeline, the candidate times of the epoch time corresponding to the second cell in the first satellite base station on the timeline, and selecting one candidate time from the candidate times of the epoch time corresponding to the second cell in the first satellite base station as the time of the epoch time corresponding to the second cell in the first satellite base station on the timeline. The order of this candidate time and the first time on the timeline satisfies the order of the epoch time corresponding to the second cell in the first satellite base station and the first time indicated by the first information.

[0278] If, among the candidate times of the epoch time corresponding to the second cell in the first satellite base station on the time axis, there exists at least one candidate time whose order with the first time satisfies the order of the epoch time corresponding to the second cell in the first satellite base station and the first time as indicated by the first information, then the candidate time that is closest to the first time on the time axis is selected as the time of the epoch time corresponding to the second cell in the first satellite base station on the time axis.

[0279] Using time on a timeline to represent absolute time, taking the absolute time difference between the epoch time corresponding to the second cell in the first satellite base station and the first time as an example, the terminal determining the absolute time of the epoch time corresponding to the second cell in the first satellite base station may include: the terminal determining the time of the first time on the timeline, candidate times of the epoch time corresponding to the second cell in the first satellite base station on the timeline, and the first information; and selecting a candidate time from the candidate times of the epoch time corresponding to the second cell in the first satellite base station as the time of the epoch time corresponding to the second cell in the first satellite base station on the timeline. The absolute value of the time difference between this candidate time and "the sum of the time of the first time on the timeline and the time of the absolute time difference indicated by the first information on the timeline" is minimized.

[0280] S1606: The terminal determines the status of the first satellite base station based on the absolute time of the epoch time corresponding to the second cell in the first satellite base station.

[0281] Specifically, the terminal determines the state (position and / or velocity) of the first satellite base station when the absolute time of the second cell in the first satellite base station arrives, based on the absolute time of the epoch time corresponding to the second cell in the first satellite base station and the location status information corresponding to the epoch time of the second cell in the first satellite base station. Furthermore, the terminal can calculate relevant parameters such as Doppler frequency offset, timing advance (TA), and propagation delay between the terminal and the first satellite base station in this state, enabling the terminal to access uplink and downlink services normally.

[0282] based on Figure 16 The communication method shown, in a scenario where the terminal receives SIB19 data from a first satellite base station, allows the terminal to obtain the absolute time of the epoch corresponding to the second cell in the first satellite base station based on the relative relationship between the epoch time of the second cell and the first time. This adds new information (the relative relationship between the epoch time of the second cell and the first time) to the terminal's determination of the absolute time of the epoch corresponding to the second cell in the first satellite base station when the terminal receives SIB19 data. This allows the terminal to obtain the absolute time of the epoch corresponding to the second cell in the first satellite base station based on the new information, avoiding the problem of inaccurate determination of the absolute time of the epoch corresponding to the second cell in the first satellite base station and ensuring the usability of the satellite ephemeris information of the first satellite base station. Simultaneously, the terminal does not introduce "state rollback" latency. That is, it avoids the latency of repeatedly determining the absolute time of the epoch corresponding to the cell in the satellite base station after the terminal has determined it to be inaccurate.

[0283] Figure 16The communication method shown provides a scenario where a terminal receives SIB19 data from a first satellite base station. The first information includes the relative relationship between epoch time and first time, enabling the terminal to accurately obtain the absolute time of the epoch time corresponding to the second cell in the first satellite base station based on the first information, thus ensuring that the satellite ephemeris information of the second satellite base station is usable. The following example illustrates this. Figure 17 Taking the communication method shown as an example, a communication method is provided in which a terminal receives SIB19 from a first satellite base station, and the first information is satellite ephemeris information, so that the terminal can accurately obtain the absolute time of the epoch time corresponding to the second cell in the first satellite base station based on the first information, thereby ensuring that the satellite ephemeris information of the first satellite base station is usable.

[0284] Figure 17 This is a flowchart illustrating a communication method provided in an embodiment of this application, such as... Figure 17 As shown, the method may include:

[0285] S1701: The first satellite base station obtains the target epoch time corresponding to the second cell in the first satellite base station according to the preset constraints corresponding to the neighboring cells.

[0286] The preset constraints for neighboring cells are: the epoch time and the first time are points within the same preset time period, and the duration of the preset time period is less than or equal to a preset threshold. The duration of the preset time period is less than or equal to a preset value. 0 is less than the preset value, and the preset value is less than or equal to 5.12s.

[0287] In this application, the preset constraints corresponding to the neighboring cell refer to the preset constraints under the condition that the satellite ephemeris information is the satellite ephemeris information of the neighboring cell.

[0288] Specifically, the first satellite base station will use any time within a preset time period as the epoch time corresponding to the second cell in the first satellite base station.

[0289] S1702: The first satellite base station obtains the location status information corresponding to the epoch time of the second cell in the first satellite base station.

[0290] Specifically, the first satellite base station can obtain the location status information corresponding to the epoch time of the second cell in the first satellite base station from the module that manages the relevant configuration information of the first satellite base station, according to existing technology.

[0291] S1703: The first satellite base station sends SIB19 to the terminal within a preset time period, and the terminal receives SIB19 within the preset time period.

[0292] The SIB19 can include the epoch time and location status information corresponding to the epoch time of the second cell in the first satellite base station. That is, the SIB19 includes the satellite ephemeris information of the second cell in the first satellite base station. For example, in a scenario where the terminal receives an SIB19 carrying satellite ephemeris information of a neighboring cell from the first satellite base station, the length of the first time period (len) is 5 seconds, and the start time of the first time period is 0 seconds. Based on preset constraints corresponding to the neighboring cell, the first satellite base station uses the end time of the first time period, i.e., 5 seconds, as the target epoch time for the second cell in the first satellite base station. The first satellite base station obtains the location status information of the second cell in the first satellite base station at 5 seconds from the module managing the relevant configuration information of the first satellite base station. Further, the first satellite base station broadcasts the SIB19 to the terminal within 0-5 seconds. The SIB19 includes the epoch time of the second cell in the first satellite base station and the location status information corresponding to the epoch time of the second cell in the first satellite base station.

[0293] S1704: Terminal resolution of SIB19.

[0294] For details regarding S1704, please refer to the relevant descriptions of S1604; they will not be repeated here.

[0295] S1705: The terminal determines the absolute time of the epoch time corresponding to the second cell in the first satellite base station.

[0296] Specifically, the terminal selects a candidate absolute time from the candidate absolute times of the epoch time corresponding to the second cell in the first satellite base station, and uses this as the absolute time of the epoch time corresponding to the second cell in the first satellite base station. The absolute value of the time difference between a candidate absolute time and the first time is less than a preset threshold.

[0297] The preset threshold can be found in the relevant description in S1003, and will not be repeated here.

[0298] S1705: The terminal determines the status of the first satellite base station based on the absolute time of the epoch time corresponding to the second cell in the first satellite base station.

[0299] Specifically, based on the absolute time of the epoch time corresponding to the second cell in the first satellite base station and the location status information corresponding to the epoch time of the second cell in the first satellite base station, the terminal determines the state (position and / or velocity) of the first satellite base station when the absolute time of the epoch time corresponding to the second cell in the first satellite base station arrives. Furthermore, the terminal can calculate relevant parameters such as Doppler frequency offset, timing advance (TA), and propagation delay between the terminal and the first satellite base station in this state, enabling the terminal to access uplink and downlink services normally.

[0300] based on Figure 17 The communication method shown describes a scenario where the terminal receives SIB19 data from a first satellite base station. The first satellite base station determines the epoch time corresponding to the second cell within the first satellite base station based on preset constraints corresponding to neighboring cells, and sends this epoch time to the terminal via SIB19. At this time, among the candidate absolute times of the epoch time corresponding to the second cell in the first satellite base station, the candidate absolute time with the smallest absolute time difference from the "absolute time of the terminal receiving SIB19" is unique. Therefore, during the process of the terminal determining the absolute time of the epoch time corresponding to the second cell in the first satellite base station, no "critical scenario" occurs, and the absolute time of the epoch time corresponding to the second cell in the first satellite base station can be accurately determined, ensuring the usability of the satellite ephemeris information of the first satellite base station. Simultaneously, the terminal does not introduce "state rollback" latency.

[0301] The foregoing mainly describes the solutions provided by the embodiments of this application from the perspective of interaction between various devices. It is understood that each device, such as a terminal device or a first network device, includes corresponding hardware structures and / or software modules to perform the aforementioned functions. Those skilled in the art should readily recognize that, based on the algorithm steps of the examples described in conjunction with the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0302] This application embodiment can group terminal devices, first network devices, etc., into functional modules according to the above method example. For example, each functional group can correspond to a functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. It should be noted that the grouping of modules in this application embodiment is illustrative and only represents one logical functional grouping. In actual implementation, there may be other grouping methods.

[0303] Figure 18 A structural diagram of a communication device 1800 is shown, which can be used to perform the functions of the terminal device involved in the above embodiments. As one possible implementation, Figure 18 The communication device 1800 shown includes: a transceiver unit 1801 and a processing unit 1802;

[0304] The transceiver unit 1801 is used to receive first information; the first information is used to indicate the relative relationship between the epoch time and the first time; the first time is the time of receiving satellite ephemeris information; the satellite ephemeris information carries the epoch time. For example, the transceiver unit 1801 may support the communication device 1800 to execute S1106, or may support the communication device 1800 to execute S1408, or may support the communication device 1800 to execute S1603, or may support the communication device 1800 to execute S1703.

[0305] Processing unit 1102 is configured to determine the absolute time of the epoch time based on the first information. For example, processing unit 1802 may support communication device 1800 to execute S1108, or may support communication device 1800 to execute S1410, or may support communication device 1800 to execute S1605, or may support communication device 1800 to execute S1704.

[0306] The descriptions of the first information, epoch time, satellite ephemeris information, absolute time of the epoch time, and the relative relationship between the epoch time and the first time can be referred to the above method embodiments.

[0307] Specifically, the above Figure 11 , Figure 14 , Figure 16 as well as Figure 17 All relevant content regarding each step involved in the terminal in the illustrated method embodiment can be referenced from the functional description of the corresponding functional module, and will not be repeated here. The communication device 1800 is used to execute... Figure 11 , Figure 14 , Figure 16 as well as Figure 17 The terminal in the communication method shown can achieve the same effect as the communication method described above.

[0308] Figure 19 A structural diagram of a communication device 1900 is shown, which can be used to perform the functions of the first network device involved in the above embodiments. As one possible implementation, Figure 19 The communication device 1900 shown includes: a processing unit 1901 and a transceiver unit 1902;

[0309] Processing unit 1901 is configured to acquire first information, wherein the first information indicates the relative relationship between the epoch time and the first time; the first time is the time of receiving satellite ephemeris information; the satellite ephemeris information carries the epoch time. For example, processing unit 1901 may support communication device 1900 to execute S1105, or may support communication device 1800 to execute S1402-S1407, or may support communication device 1800 to execute S1601-S1602, or may support communication device 1800 to execute S1701-S1703.

[0310] The transceiver unit 1902 is used to transmit first information. For example, the transceiver unit 1902 may support the communication device 1900 to execute S1106, or may support the communication device 1900 to execute S1408, or may support the communication device 1900 to execute S1603, or may support the communication device 1900 to execute S1703.

[0311] The descriptions of the first information, epoch time, satellite ephemeris information, absolute time of the epoch time, and the relative relationship between the epoch time and the first time can be referred to the above method embodiments.

[0312] Specifically, the above Figure 11 , Figure 14 , Figure 16 as well as Figure 17 All relevant content regarding the steps involved in the first satellite base station in the illustrated method embodiment can be referenced from the functional descriptions of the corresponding functional modules, and will not be repeated here. The communication device 1900 is used to execute... Figure 11 , Figure 14 , Figure 16 as well as Figure 17 The communication method shown can achieve the same effect as the communication method described above by having the function of the first satellite base station.

[0313] The aforementioned processing unit can be a processing module, a processor, or a controller. It can implement or execute various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. A processor can also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc. A transceiver unit can be a communication module, a transceiver circuit, or a communication interface, etc. Any of the aforementioned communication devices can also include a storage unit for storing the program code and data of any communication device. The storage unit can be a storage module or a memory. When the processing module is a processor, the communication module is a communication interface, and the storage module is a memory, the communication devices 1800 and 1900 involved in the embodiments of this application can be... Figure 20The communication device 2000 shown. For example, the aforementioned terminal and the first satellite base station can be adopted. Figure 20 The shown composition or includes Figure 20 The components shown. Figure 20 This is a schematic diagram illustrating the composition of a communication device 2000 provided in an embodiment of this application, as shown below. Figure 20 As shown, the communication device 2000 may include a processor 2001, and optionally, may also include a communication line 2002 and a communication interface 2003.

[0314] Furthermore, the communication device 2000 may also include a memory 2004. The processor 2001, the memory 2004, and the communication interface 2003 can be connected via a communication line 2002.

[0315] The processor 2001 can be a central processing unit (CPU), a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The processor 2001 can also be other communication devices with processing capabilities, such as circuits, devices, or software modules.

[0316] Communication line 2002 is used to transmit information between the components included in communication device 2000.

[0317] Communication interface 2003 is used for communication with other devices or other communication networks. These other communication networks can be Ethernet, radio access network (RAN), wireless local area network (WLAN), etc. Communication interface 2003 can be a radio frequency module, transceiver, or any communication device capable of communication. This application embodiment uses a radio frequency module as an example to illustrate communication interface 2003. The radio frequency module can include an antenna, radio frequency circuitry, etc., and the radio frequency circuitry can include a radio frequency integrated chip, a power amplifier, etc.

[0318] Memory 2004 is used to store instructions. These instructions can be computer programs.

[0319] The memory 2004 can be a read-only memory (ROM) or other type of static storage device that can store static information and / or instructions; it can also be a random access memory (RAM) or other type of dynamic storage device that can store information and / or instructions; it can also be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage, magnetic disk storage media or other magnetic storage devices. Optical disc storage includes compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.

[0320] It should be noted that the memory 2004 can exist independently of the processor 2001, or it can be integrated with the processor 2001. The memory 2004 can be used to store instructions, program code, or some data, etc. The memory 2004 can be located inside or outside the communication device 2000, without limitation. The processor 2001 is used to execute the instructions stored in the memory 2004 to implement the random access procedure preamble transmission method provided in the following embodiments of this application.

[0321] In one example, processor 2001 may include one or more CPUs, for example Figure 20 CPU0 and CPU1 in the CPU.

[0322] As an optional implementation, the communication device 2000 includes multiple processors, for example, besides Figure 20 In addition to processor 2001, it may also include processor 2007.

[0323] As an optional implementation, the communication device 2000 also includes an output device 2005 and an input device 2006. The input device 2006 is a keyboard, mouse, microphone, or joystick, etc., and the output device 2005 is a display screen, speaker, etc.

[0324] It should be noted that the communication device 2000 can be a desktop computer, laptop computer, network server, mobile phone, tablet computer, wireless terminal, embedded device, chip system, or something similar. Figure 20 Equipment with a similar structure. Furthermore... Figure 20 The structural composition shown does not constitute a limitation on the communication device, except... ​In addition to the components shown, the communication device may include more or fewer components than illustrated, or combine certain components, or have different component arrangements.

[0325] In this embodiment of the application, the chip system may be composed of chips or may include chips and other discrete devices.

[0326] This application also provides a computer-readable storage medium. All or part of the processes in the above method embodiments can be implemented by a computer program instructing related hardware. This program can be stored in the computer-readable storage medium, and when executed, it can include the processes of the above method embodiments. The computer-readable storage medium can be a terminal device of any of the foregoing embodiments, such as an internal storage unit including a data transmission end and / or a data receiving end, like a hard disk or memory of the terminal device. The computer-readable storage medium can also be an external storage device of the terminal device, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the terminal device. Further, the computer-readable storage medium can include both internal storage units and external storage devices of the terminal device. The computer-readable storage medium is used to store the computer program and other programs and data required by the terminal device. The computer-readable storage medium can also be used to temporarily store data that has been output or will be output.

[0327] It should be understood that the collection, storage, use, processing, transmission, provision, and disclosure of user personal information involved in the technical solution of this application all comply with relevant laws and regulations and do not violate public order and good morals. For example, in the technical solution of this application, the processing of user personal information is carried out with the user's authorization, and this will not be repeated hereafter.

[0328] It should be noted that the terms "first" and "second," etc., in the specification, claims, and drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0329] It should be understood that in this application, "at least one (item)" means one or more, "more than one" means two or more, "at least two (items)" means two or three or more, and "and / or" is used to describe the relationship between related objects, indicating that there can be three relationships. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the related objects before and after are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0330] It should be understood that in the embodiments of this application, "B corresponding to A" means that B is associated with A. For example, B can be determined based on A. It should also be understood that determining B based on A does not mean that B is determined solely based on A; B can also be determined based on A and / or other information. Furthermore, the term "connection" in the embodiments of this application refers to various connection methods, such as direct connection or indirect connection, to achieve communication between devices, and the embodiments of this application do not impose any limitations on this.

[0331] Unless otherwise specified, the term "transmission" in the embodiments of this application refers to bidirectional transmission, encompassing the actions of sending and / or receiving. Specifically, "transmission" in the embodiments of this application includes sending data, receiving data, or both sending and receiving data. In other words, data transmission here includes uplink and / or downlink data transmission. Data may include channels and / or signals; uplink data transmission refers to uplink channel and / or uplink signal transmission, and downlink data transmission refers to downlink channel and / or downlink signal transmission. The terms "network" and "system" in the embodiments of this application refer to the same concept; a communication system is a communication network.

[0332] Through the above description of the embodiments, those skilled in the art can clearly understand that, for the sake of convenience and brevity, only the grouping of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0333] In the several embodiments provided in this application, it should be understood that the disclosed communication devices and methods can be implemented in other ways. For example, the communication device embodiments described above are merely illustrative. For instance, the grouping of modules or units is only a logical functional grouping, and in actual implementation, there may be other grouping methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, or indirect coupling or communication connection between devices or units, and may be electrical, mechanical, or other forms.

[0334] The units described as separate components may or may not be physically separate. A component shown as a unit can be one or more physical units; that is, it can be located in one place or distributed in multiple different locations. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0335] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0336] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, essentially, or the parts that contribute to the prior art, or all or part of the technical solutions, can be embodied in the form of a software product. This software product is stored in a storage medium and includes several instructions to cause a device, such as a microcontroller, chip, or processor, to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media for storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0337] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A communication method characterized by comprising: The method comprises: receiving first information; the first information is used to indicate the relative relationship between the epoch time and the first time; the first time is the time of receiving satellite ephemeris information; the satellite ephemeris information carries the epoch time; determining the absolute time of the epoch time according to the first information.

2. The method of claim 1, wherein, The first information comprises the relative relationship between the epoch time and the first time; the method further comprises: receiving the satellite ephemeris information at the first time.

3. The method according to claim 2, wherein the first information is used to indicate the relative relationship between the epoch time and the first time, comprising: the first information is used to indicate the order of the epoch time and the first time, and / or, the first information is used to indicate the absolute time difference between the epoch time and the first time.

4. The method of claim 3, wherein, The determination of the absolute time of the epoch time according to the first information comprises: selecting one candidate absolute time from the candidate absolute time of the epoch time as the absolute time of the epoch time according to the first information; wherein the order of the one candidate absolute time and the first time satisfies the order of the epoch time and the first time indicated by the first information, the candidate absolute time of the epoch time comprises the time corresponding to the epoch time in each equivalent superframe; the time length of the equivalent superframe is a preset value.

5. The method according to claim 3 or 4, characterized in that, The order of the epoch time and the first time comprises: the epoch time is earlier than the first time, or, the epoch time is later than the first time, or, the epoch time is equal to the first time.

6. The method of claim 3, wherein, The determination of the absolute time of the epoch time according to the first information comprises: selecting one candidate absolute time from the candidate absolute time of the epoch time as the absolute time of the epoch time according to the first information; the absolute time difference between the one candidate absolute time and "the time of the first time plus the absolute time difference indicated by the first information" is less than a preset threshold; the candidate absolute time of the epoch time comprises the time corresponding to the epoch time in each equivalent superframe; the time length of the equivalent superframe is a preset value.

7. The method of claim 1, wherein, The first information is the satellite ephemeris information, and the epoch time is obtained according to a preset constraint condition, and the constraint condition is used to constrain the relative time relationship between the epoch time and the first time.

8. The method according to claim 7, wherein the satellite ephemeris information is satellite ephemeris information of a target cell; the preset constraint condition is that the epoch time is less than the first time; wherein the target cell is a cell that replaces a serving cell to provide services for a terminal device, and the serving cell is a cell that currently provides services for the terminal device.

9. The method according to claim 7, wherein the satellite ephemeris information is satellite ephemeris information of a neighbor cell; the preset constraint condition is that the epoch time and the first time are time points in a same preset time period. The neighbor cell is a cell adjacent to a serving cell, and the serving cell is a cell currently providing services for the terminal device.

10. The method of claim 9, wherein a length of the preset time period is less than or equal to a preset threshold.

11. The method of any one of claims 1-10, wherein the first information is carried in system information (SI).

12. The method of any one of claims 1-10, wherein the first information is carried in radio resource control (RRC) signaling. The method comprises: obtaining first information; 12. A communication method, comprising: sending the first information, the first information being used to indicate a relative relationship between an epoch time and a first time, the first time being a time at which satellite ephemeris information is received, and the satellite ephemeris information carrying the epoch time. The first information includes the relative relationship between the epoch time and the first time, and the method further comprises: sending the satellite ephemeris information.

13. The method of claim 12, wherein, 14. The method of claim 13, wherein the first information used to indicate the relative relationship between the epoch time and the first time comprises: the first information being used to indicate an order of the epoch time and the first time, and / or the first information being used to indicate an absolute time difference between the epoch time and the first time. The obtaining of the first information comprises: obtaining the epoch time; determining the relative relationship between the epoch time and the first time according to the epoch time and the first time; 15. The method of claim 14, wherein, obtaining the first information according to the relative relationship between the epoch time and the first time. The epoch time is an epoch time of a target cell, and the obtaining of the epoch time comprises: sending a handover request, the handover request being used to request allocation of resources for a terminal device; in response to the handover request, receiving the epoch time of the target cell, the target cell being a cell that takes over a service cell to provide services for the terminal device, and the service cell being a cell currently providing services for the terminal device.

16. The method of claim 15, wherein, 17. The method of any one of claims 14-16, wherein the order of the epoch time and the first time comprises: the epoch time being earlier than the first time, or the epoch time being later than the first time, or the epoch time being equal to the first time. The first information is the satellite ephemeris information, and the epoch time is obtained according to a preset constraint condition, the constraint condition being used to constrain a relative time relationship between the epoch time and the first time. The first information is the satellite ephemeris information, and the obtaining of the first information comprises: obtaining the epoch time according to the preset constraint condition; obtaining position state information corresponding to the epoch time according to the epoch time, the position state information being used to indicate a position and / or a speed of a satellite communication device; 18. The method of claim 12, wherein, carrying the epoch time and the position state information corresponding to the epoch time in the satellite ephemeris information.

19. The method of claim 18, wherein, The first information is satellite ephemeris information of a target cell, and the obtaining of the position state information corresponding to the epoch time according to the epoch time comprises: ​ ​ ​ 20. The method of claim 19, wherein, ​ sending a first request message carrying the epoch time, the first request message being used to request position state information corresponding to the epoch time; in response to the first request message, receiving second information, the second information including the position state information corresponding to the epoch time.

21. The method of any one of claims 18-20, wherein, the satellite ephemeris information is satellite ephemeris information of a target cell; the preset constraint condition is that the epoch time is less than the first time; wherein the target cell is a cell that takes over to provide service for the terminal device, and the serving cell is a cell that currently provides service for the terminal device.

22. The method of claim 18 or 19, wherein, the satellite ephemeris information is satellite ephemeris information of a neighbor cell; the preset constraint condition is that the epoch time and the first time are time points in a same preset time period; wherein the neighbor cell is a cell adjacent to a serving cell, and the serving cell is a cell that currently provides service for the terminal device.

23. The method of claim 22, wherein, a length of the preset time period is less than or equal to a preset threshold.

24. A communications device, characterized by The communication device is configured to support performing the communication method of any one of claims 1-11.

25. A communications device, characterized by The communication device is configured to support performing the communication method of any one of claims 12-23.

26. A communications device, characterized by The communication device comprises a processor configured to support the communication device to perform the communication method of any one of claims 1-11, or to perform the method of any one of claims 12-23.

27. A communication system, characterized by The communication system comprises the communication device of claim 24, the communication device of claim 25.

28. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer instructions that, when executed on a computer, cause the computer to perform the method of any one of claims 1-11, or cause the computer to perform the method of any one of claims 12-23.

29. A computer program product, characterised in that, The computer program product comprises computer instructions that, when executed on a computer, cause the computer to perform the method of any one of claims 1-11, or cause the computer to perform the method of any one of claims 12-23.

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