Timing advance (TA) determination method and communication device

Abstract

The present application provides a timing advance (TA) determination method and a communication device capable of reducing the occurrence of error jumps when determining the TA adjustment amount, thus increasing the accuracy of the TA adjustment amount. The method comprises: a terminal device receives a first TA command (TAC) at a first moment; if a first parameter has been updated within a first time interval before the first moment, the terminal device determines a TA adjustment amount on the basis of the first TAC and the component value of a first TA amount; and then the terminal device communicates with a service satellite on the basis of the TA adjustment amount. The first TA amount is determined by the terminal device at a second moment, and the first time interval is the time interval between the second moment and the first moment; the first parameter comprises one or more of the following information: positioning information of the terminal device, ephemeris information of a serving satellite, and a common TA.

Description

A timing advance TA determination method and communication device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of the People's Republic of China on September 27, 2023, with application number 202311270998.2 and application name “A method for determining a timing advance TA and a communication device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of communication technology, and in particular to a timing advance (TA) determination method and a communication device. Background Art

[0004] Because different user equipment (UE) are at different distances from the base station, uplink information sent by different UEs will arrive at the base station at different times, causing signal interference. Therefore, the base station hopes that the arrival times of signals from different UEs in the same subframe are roughly aligned. This way, the base station can correctly receive the uplink data sent by the UE. To ensure that the base station can correctly receive the UE uplink data, timing advance (TA) is introduced.

[0005] In terrestrial communications, the base station can estimate the UE's TA (TA varies for UEs at different distances from the base station) using the random access preamble sent by the UE. The base station then notifies the UE of the timing advance command (TAC), which the UE uses to determine the TA adjustment amount. Different UEs send uplink data based on the corresponding TA adjustment amounts. From the base station's perspective, all uplink and downlink system frames are aligned, and the base station can receive uplink data from multiple UEs in the same subframe. The above-mentioned TAC mechanism can be understood as a closed-loop TA adjustment mechanism.

[0006] In satellite communications, the distance between the satellite and the UE is long, resulting in significant latency. The TA adjustment value determined solely based on the TAC is inaccurate. Therefore, an open-loop TA adjustment mechanism is introduced to ensure uplink synchronization in satellite communications. In this mechanism, the terminal calculates the round-trip transmission delay from the terminal to the satellite based on ephemeris information and its own geographic location. This is used as the open-loop TA adjustment information when transmitting the uplink signal. The TAC closed-loop timing is adjusted in advance to compensate for errors in the open-loop TA adjustment information, thereby determining the TA adjustment value.

[0007] In satellite communications, on the one hand, after receiving the TAC, the terminal determines the current TA by accumulating the previous TA (this TA may compensate for the errors of the global navigation satellite system (GNSS), ephemeris information and public TA information). On the other hand, when the terminal updates its position or monitors ephemeris information, the errors of ephemeris information, public TA information and GNSS may be accumulated into the TA again. These two aspects cause the TA error to jump, which in turn leads to inaccurate determined TA adjustment amount.

[0008] Summary of the Invention

[0009] The present application provides a timing advance (TA) determination method and a communication device to reduce error jumps when determining a TA adjustment amount and improve the accuracy of the TA adjustment amount.

[0010] In a first aspect, the present application provides a method for determining a timing advance TA, which can be executed by a terminal device. The terminal device can be understood as a UE, a vehicle-mounted device, a terminal chip, etc. The present application does not specifically limit the type of terminal. The terminal can communicate with a satellite. In the present application, the satellite can be a geostationary satellite, a non-geostationary satellite, an artificial satellite, a low-orbit satellite, a medium-orbit satellite, and a high-orbit satellite. The present application does not specifically limit it. The method includes: the terminal device receives a first timing advance command TAC at a first moment; if the first parameter is updated within a first time period before the first moment, the terminal device determines the TA adjustment amount based on the component of the first timing advance and the first TAC; wherein the first timing advance amount is determined by the terminal device at the second moment, and the first time period is the time period between the second moment and the first moment; the first parameter includes one or more of the following information: the positioning information of the terminal device, the ephemeris information of the serving satellite, and the public timing advance TA; and the terminal device communicates with the serving satellite according to the TA adjustment amount.

[0011] In the above design, the first parameter update is used as the trigger condition to reduce the error compensation of the closed-loop TA adjustment mechanism (TA corresponding to TAC), which can reduce the error jump when determining the TA adjustment amount and ensure the accuracy of the TA adjustment amount.

[0012] In one possible design, TA adjusts the amount T TA Satisfies the following relationship: T TA =(N TA_new +N TA,UE-specific +N TA,common +N TA,offset )×T c ;

[0013] in, NTA_old is the first timing advance, α×N TA_old represents the component of the first timing advance, 0≤α<1, T A is the timing advance determined based on the first TAC, μ is a coefficient determined based on the subcarrier spacing corresponding to the terminal device; N TA,UE-specific The timing advance determined based on the ephemeris information of the service satellite and the positioning information of the terminal equipment; N TA,common N is the timing advance associated with the public TA information; TA,offset is the preconfigured timing offset; T c The minimum time unit.

[0014] The above method can be applied to specific communication scenarios. In different communication scenarios, the information included in the first parameter can be different. The specific information of the first parameter in different communication scenarios is described in detail below.

[0015] In one possible design, the service satellite is a geostationary orbit (GEO) satellite, and the first parameter includes positioning information of the terminal device.

[0016] In one possible design, the service satellite is a low-orbit LEO satellite, and the terminal device is in a stationary state, and the first parameter includes the ephemeris information of the service satellite.

[0017] In one possible design, the serving satellite is a low-Earth orbit (LEO) satellite, and the terminal device is in motion. The first parameter includes positioning information of the terminal device and / or ephemeris information of the serving satellite. Specifically, in this design, the first parameter includes information related to one or more of the following: the terminal device's moving speed, the serving satellite's orbital altitude, an error in the ephemeris satellite, and an error in the positioning information. Some examples are as follows:

[0018] If the moving speed of the terminal device is greater than a first speed threshold, the first parameter includes the positioning information of the terminal device and the ephemeris information of the service satellite; or, if the moving speed of the terminal device is less than a second speed threshold, the first parameter includes the ephemeris information of the service satellite; or, if the orbital altitude of the service satellite is lower than the first altitude threshold, the first parameter includes the ephemeris information of the service satellite; or, if the orbital altitude of the service satellite is higher than the second altitude threshold, the first parameter includes the positioning information of the terminal device; or, if the moving speed of the terminal device is greater than the first speed threshold and the orbital altitude of the service satellite is higher than the second altitude threshold, the first parameter includes the positioning information of the terminal device; or, if the moving speed of the terminal device is less than the second speed threshold and the orbital altitude of the service satellite is lower than the first altitude threshold, the first parameter includes the ephemeris information of the service satellite; or, if the error corresponding to the ephemeris information of the service satellite is less than the first error threshold, the first parameter includes the positioning information of the terminal device; or, if the error corresponding to the positioning information of the terminal device is less than the second error threshold, the first parameter includes the ephemeris information of the terminal device.

[0019] Optionally, the thresholds in the above design may be indicated to the terminal device by the serving satellite, or may be predefined or configured in the terminal device. For example, before determining the TA adjustment amount, the terminal device may further perform the following operation: receive first information from the serving satellite, where the first information indicates one or more of the following: a first speed threshold, a second speed threshold, a first altitude threshold, a second altitude threshold, a first error threshold, and a second error threshold.

[0020] Secondly, this application provides a method for determining a timing advance (TA). This method can be performed by a terminal device, which can be understood as a UE, an on-board device, a terminal chip, etc. This application does not specifically limit the type of terminal. The terminal can communicate with a satellite. In this application, the satellite can be a geostationary satellite, a non-geostationary satellite, an artificial satellite, a low-orbit satellite, a medium-orbit satellite, or a high-orbit satellite. This application does not specifically limit this.

[0021] The method includes: a terminal device receives first information, the first information indicating I moments at which the terminal device sends a random access sequence, the interval between every two moments in the I moments being the same, and I being a positive integer greater than 1; the terminal device sends a random access sequence at the i-th moment in the I moments, and receives a second timing advance command TAC at a third moment; wherein the third moment is a moment between the i-th moment and the i+1-th moment, and i is a positive integer from 1 to I-1; the terminal device determines a TA adjustment amount based on the second TAC; wherein the second timing advance amount is determined by the terminal device before the third moment; and the terminal device communicates with a service satellite based on the TA adjustment amount.

[0022] In the above design, the terminal device sends a random access sequence based on the accumulated historical TAC N TA The reset feature configures the periodic transmission of random access sequences to achieve periodic and multiple reductions in the error compensation of the closed-loop TA adjustment mechanism, which can reduce the error jump when determining the TA adjustment amount and ensure the accuracy of the TA adjustment amount.

[0023] In one possible design, the second TAC is the first TAC received by the terminal device after the i-th moment. Optionally, the TA adjustment amount is valid for a period of time between the third moment and the next TAC after the second TAC is received.

[0024] In one possible design, TA adjusts the amount T TA Satisfies the following relationship: T TA =(N TA +N TA,UE-specific +N TA,common +N TA,offset )×T c ;

[0025] in, T A is the timing advance determined based on the second TAC, μ is a coefficient determined based on the subcarrier spacing corresponding to the terminal device; N TA,UE-specific The timing advance determined based on the ephemeris information of the service satellite and the positioning information of the terminal equipment; N TA,common N is the timing advance associated with the public TA information; TA,offset is the preconfigured timing offset; T c The minimum time unit.

[0026] In one possible design, before receiving the first information, the terminal device may also send second information to the service satellite. The second information is used to indicate the valid time of the positioning information of the terminal device, and the second information is used to determine the interval between each two moments in I moments.

[0027] Thirdly, this application provides a method for determining a timing advance (TA). This method can be performed by a terminal device, which can be understood as a UE, an on-board device, a terminal chip, etc. This application does not specifically limit the type of terminal. The terminal can communicate with a satellite. In this application, the satellite can be a geostationary satellite, a non-geostationary satellite, an artificial satellite, a low-orbit satellite, a medium-orbit satellite, or a high-orbit satellite. This application does not specifically limit this.

[0028] The method includes: when the terminal device determines to update the first parameter, the terminal device sends second information to the serving satellite, where the second information is used to request configuration information of a random access sequence; wherein the first parameter includes one or more of the following information: positioning information of the terminal device, ephemeris information of the serving satellite, and public timing advance (TA) information; the terminal device sends a random access sequence according to the received configuration information of the random access sequence; the terminal device receives a third timing advance command (TAC) and determines a TA adjustment amount according to the third TAC; wherein the third TAC is the first TAC received by the terminal device after sending the random access sequence; and the terminal device communicates with the serving satellite according to the TA adjustment amount.

[0029] In the above design, the terminal device uses the N corresponding to the historical TAC accumulated when sending the random access sequence TA The zeroing feature requests the network side to send a random access sequence during the positioning information or ephemeris information update process to reduce the error compensation of the closed-loop TA adjustment mechanism. This can reduce the error jump when determining the TA adjustment amount and ensure the accuracy of the TA adjustment amount.

[0030] In one possible design, TA adjusts the amount T TA Satisfies the following relationship: T TA =(N TA +N TA,UE-specific +N TA,common +N TA,offset )×T c ;

[0031] in, T A is the timing advance determined based on the third TAC, μ is a coefficient determined based on the subcarrier spacing corresponding to the terminal device; N TA,UE-specific The timing advance determined based on the ephemeris information of the service satellite and the positioning information of the terminal equipment; N TA,common N is the timing advance associated with the public TA information; TA,offset is the preconfigured timing offset; T c The minimum time unit.

[0032] In a fourth aspect, the present application provides a communication device, which can be used to execute the method of the first aspect. The device can be a terminal device, or the device can be a component in the terminal device (for example, a chip, or a chip system, or a circuit), or it can be a device that can be used in conjunction with the terminal device.

[0033] In one possible implementation, the communication device may include a module or unit corresponding to each of the methods / operations / steps / actions described in the first aspect. The module or unit may be a hardware circuit, software, or a combination of a hardware circuit and software. In one possible implementation, the device may include a processing unit (also referred to as a processing module) and a communication unit (also referred to as a communication module), wherein the communication unit may be used to perform the functions of receiving and / or sending, and the processing unit may be used to perform the above-mentioned first aspect or any possible implementation method of the first aspect.

[0034] Taking the communication device including a communication module and a processing module as an example, the functions of each module can be understood as follows:

[0035] The communication module is configured to receive a first timing advance command TAC at a first moment.

[0036] A processing module is used to determine a TA adjustment amount based on components of a first timing advance and a first TAC when a first parameter is updated within a first time period before a first moment; wherein the first timing advance is determined by the terminal device at a second moment, and the first time period is a time period between the second moment and the first moment; the first parameter includes one or more of the following information: positioning information of the terminal device, ephemeris information of the service satellite, and a public timing advance TA.

[0037] The communication module is also used to communicate with the service satellite according to the TA adjustment amount.

[0038] In one possible design, TA adjusts the amount T TA Satisfies the following relationship: T TA =(N TA_new +N TA,UE-specific +N TA,common +N TA,offset )×T c ;

[0039] in, N TA_old is the first timing advance, α×N TA_old represents the component of the first timing advance, 0≤α<1, T A is the timing advance determined based on the first TAC, μ is a coefficient determined based on the subcarrier spacing corresponding to the terminal device; N TA,UE-specific The timing advance determined based on the ephemeris information of the service satellite and the positioning information of the terminal equipment; N TA,common N is the timing advance associated with the public TA information; TA,offset is the preconfigured timing offset; T c The minimum time unit.

[0040] The above communication device can be applied to specific communication scenarios. In different communication scenarios, the information included in the first parameter can be different. The specific information of the first parameter in different communication scenarios is described in detail below.

[0041] In one possible design, the service satellite is a geostationary orbit (GEO) satellite, and the first parameter includes positioning information of the terminal device.

[0042] In one possible design, the service satellite is a low-orbit LEO satellite, and the terminal device is in a stationary state, and the first parameter includes the ephemeris information of the service satellite.

[0043] In one possible design, the serving satellite is a low-Earth orbit (LEO) satellite, and the terminal device is in motion. The first parameter includes positioning information of the terminal device and / or ephemeris information of the serving satellite. Specifically, in this design, the first parameter includes information related to one or more of the following: the terminal device's moving speed, the serving satellite's orbital altitude, an error in the ephemeris satellite, and an error in the positioning information. Some examples are as follows:

[0044] If the moving speed of the terminal device is greater than a first speed threshold, the first parameter includes the positioning information of the terminal device and the ephemeris information of the service satellite; or, if the moving speed of the terminal device is less than a second speed threshold, the first parameter includes the ephemeris information of the service satellite; or, if the orbital altitude of the service satellite is lower than the first altitude threshold, the first parameter includes the ephemeris information of the service satellite; or, if the orbital altitude of the service satellite is higher than the second altitude threshold, the first parameter includes the positioning information of the terminal device; or, if the moving speed of the terminal device is greater than the first speed threshold and the orbital altitude of the service satellite is higher than the second altitude threshold, the first parameter includes the positioning information of the terminal device; or, if the moving speed of the terminal device is less than the second speed threshold and the orbital altitude of the service satellite is lower than the first altitude threshold, the first parameter includes the ephemeris information of the service satellite; or, if the error corresponding to the ephemeris information of the service satellite is less than the first error threshold, the first parameter includes the positioning information of the terminal device; or, if the error corresponding to the positioning information of the terminal device is less than the second error threshold, the first parameter includes the ephemeris information of the terminal device.

[0045] Optionally, the thresholds in the above design may be indicated to the terminal device by the serving satellite, or may be predefined or configured in the terminal device. For example, before determining the TA adjustment amount, the terminal device may further perform the following operation: receive first information from the serving satellite, where the first information indicates one or more of the following: a first speed threshold, a second speed threshold, a first altitude threshold, a second altitude threshold, a first error threshold, and a second error threshold.

[0046] In the fifth aspect, the apparatus can be used to execute the method of the second aspect. The apparatus can be a terminal device, or the apparatus can be a component in the terminal device (for example, a chip, or a chip system, or a circuit), or it can be an apparatus that can be used in conjunction with the terminal device.

[0047] In one possible implementation, the communication device may include a module or unit corresponding to each of the methods / operations / steps / actions described in the second aspect. The module or unit may be a hardware circuit, software, or a combination of a hardware circuit and software. In one possible implementation, the device may include a processing unit (also referred to as a processing module) and a communication unit (also referred to as a communication module), wherein the communication unit may be used to perform the functions of receiving and / or sending, and the processing unit may be used to perform the above-mentioned second aspect or any possible implementation method of the second aspect.

[0048] Taking the communication device including a communication module and a processing module as an example, the functions of each module can be understood as follows:

[0049] A communication module is used to receive first information, where the first information indicates I moments at which a terminal device sends a random access sequence, where the interval between each two moments in the I moments is the same, and I is a positive integer greater than 1; and, sending a random access sequence at the i-th moment in the I moments, and receiving a second timing advance command TAC at the third moment; wherein the third moment is a moment between the i-th moment and the i+1-th moment, and i is a positive integer from 1 to I-1.

[0050] The processing module is used to determine a TA adjustment amount according to the second TAC; wherein the second timing advance amount is determined by the terminal device before the third moment.

[0051] The communication module is also used to communicate with the service satellite according to the TA adjustment amount.

[0052] In one possible design, the second TAC is the first TAC received by the terminal device after the i-th moment. Optionally, the TA adjustment amount is valid for a period of time between the third moment and the next TAC after the second TAC is received.

[0053] In one possible design, TA adjusts the amount T TA Satisfies the following relationship: T TA =(N TA +N TA,UE-specific +N TA,common +N TA,offset )×T c ;

[0054] in, TA is the timing advance determined based on the second TAC, μ is a coefficient determined based on the subcarrier spacing corresponding to the terminal device; N TA,UE-specific The timing advance determined based on the ephemeris information of the service satellite and the positioning information of the terminal equipment; N TA,common N is the timing advance associated with the public TA information; TA,offset is the preconfigured timing offset; T c The minimum time unit.

[0055] In one possible design, the communication module is also used to send second information to the service satellite before receiving the first information, where the second information is used to indicate the valid time of the positioning information of the terminal device, and the second information is used to determine the interval between each two moments in I moments.

[0056] In the sixth aspect, the apparatus can be used to execute the method of the third aspect. The apparatus can be a terminal device, or the apparatus can be a component in the terminal device (for example, a chip, or a chip system, or a circuit), or can be a device that can be used in conjunction with the terminal device.

[0057] In one possible implementation, the communication device may include a module or unit corresponding to each of the methods / operations / steps / actions described in the third aspect. The module or unit may be a hardware circuit, software, or a combination of a hardware circuit and software. In one possible implementation, the device may include a processing unit (also referred to as a processing module) and a communication unit (also referred to as a communication module), wherein the communication unit may be used to perform the functions of receiving and / or sending, and the processing unit may be used to perform the third aspect or any possible implementation method of the third aspect.

[0058] Taking the communication device including a communication module and a processing module as an example, the functions of each module can be understood as follows:

[0059] The processing module is configured to send second information to the serving satellite through the communication module when determining to update the first parameter, where the second information is used to request configuration information of the random access sequence; wherein the first parameter includes one or more of the following information: positioning information of the terminal device, ephemeris information of the serving satellite, and common timing advance (TA) information;

[0060] The processing module is also used to send a random access sequence through the communication module according to the configuration information of the received random access sequence; the terminal device receives a third timing advance command TAC and determines the TA adjustment amount according to the third TAC; wherein the third TAC is the first TAC received by the terminal device after sending the random access sequence.

[0061] The communication module is also used to communicate with the service satellite according to the TA adjustment amount.

[0062] In one possible design, TA adjusts the amount T TA Satisfies the following relationship: T TA =(N TA +N TA,UE-specific +N TA,common +N TA,offset )×T c ;

[0063] in, T A is the timing advance determined based on the third TAC, μ is a coefficient determined based on the subcarrier spacing corresponding to the terminal device; N TA,UE-specific The timing advance determined based on the ephemeris information of the service satellite and the positioning information of the terminal equipment; N TA,common N is the timing advance associated with the public TA information; TA,offset is the preconfigured timing offset; T c The minimum time unit.

[0064] In the seventh aspect, the present application provides a communication device comprising at least one processor and a memory; the memory is used to store computer programs or instructions, and when the device is running, the at least one processor executes the computer program or instructions to enable the communication device to perform the method of the first aspect or the various embodiments of the first aspect, or to perform the method of the second aspect or the various embodiments of the second aspect, or to perform the method of the third aspect or the various embodiments of the third aspect.

[0065] In an eighth aspect, the present application provides another communication device, comprising: a logic circuit and an input / output interface; wherein the input / output interface can be understood as an interface circuit, and the logic circuit can be used to run code instructions to execute the method of the above-mentioned first aspect or each embodiment of the first aspect, or to execute the method of the above-mentioned second aspect or each embodiment of the second aspect, or to execute the method of the above-mentioned third aspect or each embodiment of the third aspect.

[0066] In the ninth aspect, the present application also provides a computer-readable storage medium, which stores computer-readable instructions. When the computer-readable instructions are run on a computer, the computer executes the method in the first aspect or any possible design of the first aspect, or executes the method in the second aspect or any possible design of the second aspect, or executes the method in the third aspect or each embodiment of the third aspect.

[0067] In a tenth aspect, the present application provides a computer program product comprising instructions, which, when run on a computer, enables the computer to execute the method of the first aspect or the various embodiments of the first aspect, or execute the method of the second aspect or the various embodiments of the second aspect, or execute the method of the third aspect or the various embodiments of the third aspect.

[0068] In an eleventh aspect, the present application provides a chip system, comprising a processor and further comprising a memory, for implementing the method described in the first aspect or any possible design of the first aspect, or executing the method described in the second aspect or any possible design of the second aspect, or executing the method described in the third aspect or any possible design of the third aspect. The chip system may be composed of a chip, or may include a chip and other discrete devices.

[0069] In the twelfth aspect, the present application provides a communication system, which includes a terminal device and a satellite, and the communication system is used to execute the method described in the first aspect or any possible design of the first aspect, or execute the method in the second aspect or any possible design of the second aspect, or execute the method in the third aspect or any possible design of the third aspect.

[0070] For the technical effects that can be achieved in the above-mentioned fourth to twelfth aspects, please refer to the description of the technical effects that can be achieved by the corresponding possible design schemes in the above-mentioned first or second aspects, and this application will not repeat them here. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] FIG1 is a schematic diagram of a terrestrial communication system;

[0072] FIG2 is a schematic diagram of a non-terrestrial communication system provided in an embodiment of the present application;

[0073] FIG3 is a schematic diagram of the fifth generation (5G) satellite communication system architecture provided by an embodiment of the present application;

[0074] Figures 4 to 7 are flowcharts of several TA determination methods provided in embodiments of the present application;

[0075] FIG8 is a schematic structural diagram of a communication device provided in an embodiment of the present application;

[0076] FIG9 is a schematic structural diagram of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0077] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0078] The at least one (item) involved in the embodiments of the present application as follows indicates one (item) or more (items). More (items) refers to two (items) or more than two (items). "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. In addition, it should be understood that although the terms first, second, etc. may be used to describe each object in the embodiments of the present application, these objects should not be limited to these terms. These terms are only used to distinguish each object from each other.

[0079] The terms "including" and "having" and any variations thereof mentioned in the following description of the embodiments of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes other steps or units that are not listed, or optionally includes other steps or units that are inherent to these processes, methods, products or devices. It should be noted that, in the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any method or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other methods or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a concrete way.

[0080] Figure 1 shows the architecture of a terrestrial network communication system. Communication system 100 may include network device 110 and terminal devices 101-106. It should be understood that communication system 100 may include more or fewer network devices or terminal devices. Network devices or terminal devices may be hardware, functionally divided software, or a combination of the two. Furthermore, terminal devices 104-106 may also form a communication system. For example, terminal device 105 may send downlink data to terminal device 104 or terminal device 106. Network devices and terminal devices may communicate with each other through other devices or network elements. Network device 110 may send downlink data to terminal devices 101-106 and may also receive uplink data sent by terminal devices 101-106. Of course, terminal devices 101-106 may also send uplink data to network device 110 and receive downlink data sent by network device 110.

[0081] The network device 110 is a node in the radio access network (RAN), which can also be called a base station or a RAN node (or device). Currently, some examples of access network devices include: gNB / NR-NB, transmission reception point (TRP), evolved Node B (eNB), radio network controller (RNC), Node B (NB), base station controller (BSC), base transceiver station (BTS), home base station (e.g., home evolved NodeB, or home Node B, HNB), base band unit (BBU), or wireless fidelity (Wifi) access point (AP), or network devices in 5G communication systems, or network devices in possible future communication systems. The network device 110 can also be other devices with network device functions, for example, the network device 110 can also be a device that functions as a network device in D2D communication. The network device 110 can also be a network device in possible future communication systems.

[0082] Terminal devices 101-106, also known as UE, mobile station (MS), or mobile terminal (MT), provide voice or data connectivity to users and may also be IoT devices. For example, terminal devices 101-106 include handheld devices and vehicle-mounted devices with wireless connectivity. Currently, terminal devices 101 to 106 may be: mobile phones, tablet computers, laptop computers, PDAs, mobile internet devices (MIDs), wearable devices (such as smart watches, smart bracelets, pedometers, etc.), vehicle-mounted devices (such as cars, bicycles, electric vehicles, airplanes, ships, trains, high-speed trains, etc.), virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, smart home devices (such as refrigerators, televisions, air conditioners, electric meters, etc.), intelligent robots, workshop equipment, wireless terminals in self-driving cars, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, flying devices (such as intelligent robots, hot air balloons, drones, airplanes), etc. The terminal devices 101 to 106 may also be other devices having terminal functions. For example, the terminal devices 101 to 106 may also be devices that serve as terminal functions in D2D communications.

[0083] Based on the description of the terrestrial network communication system architecture shown in FIG1 , the TA determination method provided in the embodiments of the present application can be applied to non-terrestrial network (NTN) communication systems. As shown in FIG2 , the NTN communication system includes a satellite 201 and a terminal device 202. The explanation of terminal device 202 can refer to the relevant description of terminal devices 101 to 106 described above. Satellite 201 can also be referred to as a high-altitude platform, a high-altitude aircraft, or a satellite base station. In relation to the NTN communication system and the terrestrial network communication system, satellite 201 can be considered as one or more network devices in the terrestrial network communication system architecture. Satellite 201 provides communication services to terminal device 202 and can also be connected to core network equipment. The structure and functions of the satellite can also refer to the description of the network device described above. The communication method between satellite 201 and terminal device 202 can also refer to the description in FIG1 . No further details will be given here.

[0084] Taking 5G as an example, a 5G satellite communication system architecture is shown in Figure 3. Ground-based terminal devices access the network via the 5G new air interface. 5G base stations are deployed on satellites and connected to the ground core network via wireless links. Wireless links also exist between satellites, enabling signaling exchanges and user data transmission between base stations. The devices and interfaces in Figure 3 are described below:

[0085] 5G core network: This network provides services such as user access control, mobility management, session management, user security authentication, and billing. It consists of multiple functional units, divided into control plane and data plane functional entities. The access and mobility management function (AMF) is responsible for user access management, security authentication, and mobility management. The user plane function (UPF) manages user plane data transmission, traffic statistics, and other functions.

[0086] Ground station: responsible for forwarding signaling and service data between satellite base stations and 5G core network.

[0087] 5G New Air Interface: The wireless link between the terminal and the base station.

[0088] Xn interface: The interface between 5G base stations, mainly used for signaling interactions such as switching.

[0089] NG interface: The interface between the 5G base station and the 5G core network, which mainly interacts with the core network's NAS and other signaling, as well as user business data.

[0090] The network devices in a terrestrial network communication system and the satellites in an NTN communication system can be collectively considered network devices. The device used to implement the functions of the network device can be a network device; it can also be a device capable of supporting the network device in implementing the functions, such as a chip system, which can be installed in the network device. The following description of the technical solutions provided by the embodiments of the present application uses the example of a satellite as the device used to implement the functions of the network device. It will be understood that when the methods provided by the embodiments of the present application are applied to a terrestrial network communication system, the actions performed by the satellite can be applied to a base station or network device for execution.

[0091] In the embodiments of the present application, the device for realizing the function of the terminal device may be a terminal device; or it may be a device capable of supporting the terminal device to realize the function, such as a chip system, which may be installed in the terminal device. In the embodiments of the present application, the chip system may be composed of a chip, or may include a chip and other discrete devices. In the technical solutions provided in the embodiments of the present application, the technical solutions provided in the embodiments of the present application are described by taking the case where the device for realizing the function of the terminal device is a terminal or UE as an example.

[0092] In addition, the above-mentioned satellites can be geostationary satellites, non-geostationary satellites, artificial satellites, low-orbit satellites, medium-orbit satellites, high-orbit satellites, etc., which are not specifically limited in this application.

[0093] As described in the background technology, the TA adjustment value T used for communication between the terminal device and the service satellite in the related art is TA It can be determined according to the following relationship (1): TA =(N TA +N TA,UE-specific +N TA,common +N TA,offset )×T c ; (1)

[0094] (a)N TA :When the terminal device sends a random access sequence or sends a physical random access channel (PRACH), N TA =0. For example, in a non-contention-based random access process, the serving satellite may indicate the configuration information of the random access sequence, such as random access resources, through control signaling. Optionally, the control signaling may be a physical downlink control channel (PDCCH). Since the PDCCH indicates the configuration information of the random access sequence, the PDCCH may also be referred to as PDCCH ordered PRACH. The terminal device sends the random access sequence according to the random access resources indicated by the control signaling. At this time, NTA =0.

[0095] Furthermore, after sending the random access sequence, the terminal device receives a random access response (RAR) message from the serving satellite, wherein the RAR message includes the TAC. The terminal device can select the N based on the TA corresponding to the TAC. TA Perform an update. Subsequently, each time the terminal receives a TAC, it determines the new N by accumulating the TA corresponding to the historical TAC. TA , denoted as N TA_new That is, it can be understood that, in the case of cumulative historical TAC, N in equation (1) TA Can be replaced by description N TA_new The N TAnew It complies with the following relationship (2):

[0096] Among them, T A It can be understood as the timing advance determined based on the most recently received TAC; It can be understood that when the TA adjustment amount was determined last time, N TA μ is a coefficient determined based on the subcarrier spacing corresponding to the terminal device, for example, μ can be a scaling factor of the subcarrier spacing relative to the reference subcarrier spacing. In addition, N TA or N TA_new It can be understood as the TA corresponding to the closed-loop TA adjustment mechanism.

[0097] (b)N TA,UE-specific The timing advance is determined based on the ephemeris information of the service satellite and the positioning information of the terminal device. For example, N TA,UE-specific It refers to the round-trip transmission delay from the terminal device to the service satellite, or the round-trip transmission delay of the service link. In addition, it can be understood that the ephemeris information of the service satellite and the positioning information of the terminal device will be updated in some communication scenarios. TA The latest ephemeris information of the serving satellite and the positioning information of the terminal device are input. Optionally, the positioning information of the terminal device may be the GNSS information of the terminal device, and the terminal device may update the GNSS information on its own; the updated ephemeris information of the serving satellite may be broadcasted to the terminal device by the serving satellite.

[0098] (c)N TA,common The timing advance associated with the public TA.

[0099] The public TA refers to the round-trip transmission delay from the satellite to the reference point. The reference point can be located at the satellite, the ground station, or other locations such as a certain location on the service link from the satellite to the terminal device, or a certain location on the feeder circuit from the satellite to the ground station. This embodiment of the present application is not limited to this. TA,UE-specific +N TA,common " can be understood as the TA corresponding to the open-loop TA adjustment mechanism.

[0100] Optionally, the serving satellite may broadcast a public TA or parameters for determining a public TA, and the terminal device determines the public TA based on the received broadcast message, and determines the public TA based on the public TA and T c Determine N TA,common . T c is the minimum time unit, T c It can be pre-defined, or determined by negotiation between the terminal device and the access network device, or configured to the terminal device by the access network device.

[0101] For example, to prevent terminal devices from frequently monitoring broadcast messages, public TA parameters typically include one or more of the following: public TA, TA change rate, second-order TA change rate, third-order TA change rate, and other higher-order change rates. Based on these parameters, terminal devices can estimate the public TA within a certain time range.

[0102] (d)N TA,offset is a preconfigured timing offset, such as N TA,offset The value of is related to the communication mode between the terminal device and the service satellite. The communication mode between the terminal device and the service satellite can be time division duplex (TDD) or frequency division duplex (FDD).

[0103] It can be understood that the above-mentioned equations (1) and (2) are used as an example to determine the TA adjustment amount. In actual application, the equations can be appropriately adjusted, for example, by modifying some of the parameters in the equations. The embodiments of the present application do not limit this.

[0104] Applying the above TA adjustment mechanism to satellite communications, when the terminal receives TAC, N TA_old It will be accumulated in the TA adjustment amount determined by the terminal device to compensate for errors in the ephemeris information, public TA information, or positioning information; and the terminal can compensate for errors in the ephemeris information, public TA information, or positioning information when performing a position update or ephemeris update. Performing these two error compensations simultaneously will cause the ephemeris information, public TA information, or GNSS information determined by the terminal to increase errors, resulting in TA error jumps, and thus causing the determined TA adjustment amount to be inaccurate. An example is as follows:

[0105] Time T0: The terminal device monitors the ephemeris information or public TA information and updates the GNSS;

[0106] Time T1: The uplink signal sent by the terminal device to the network side (such as the service satellite);

[0107] At time T2, the terminal device receives the TAC and adjusts the TA adjustment amount based on the TAC. The TAC is determined by the network side after estimating the uplink signal initiated by the terminal device at time T1. The TAC can represent the error compensation for the GNSS, ephemeris information, or public TA information at time T1.

[0108] T3: The terminal device compensates for the errors of these parameters through the update of ephemeris information, GNSS or public TA information. However, the accumulated N TA_old If it still exists, the determined TA adjustment amount will be inaccurate.

[0109] In view of the above situation, the present application provides some TA determination methods to reduce the error jump when determining the TA adjustment amount, while ensuring the accuracy of the TA adjustment amount. Detailed description will be given below with reference to the accompanying drawings.

[0110] FIG4 shows a first TA determination method, which mainly includes the following process.

[0111] S401: A serving satellite sends a first timing advance command (TAC) to a terminal device, and the terminal device receives the first TAC at a first moment.

[0112] The terminal device receives at least one TAC before receiving the first TAC. The time when the terminal device receives the first TAC one TAC before the first TAC is recorded as the second time, and the time period between the second time and the first time is recorded as the first time period.

[0113] If one or more of the terminal device's positioning information, the serving satellite's ephemeris information, and the common timing advance (TA) is updated within the first time period, then the terminal device determines the TA adjustment amount based on the first TAC, which may be specifically performed with reference to S402. If one or more of the terminal device's positioning information, the serving satellite's ephemeris information, and the common timing advance (TA) is not updated within the first time period, then the TA adjustment amount is determined according to equations (1) and (2).

[0114] S402: The terminal device determines a TA adjustment amount according to components of the first timing advance and the first TAC.

[0115] The first timing advance is determined by the terminal device at the second moment. For example, the terminal device can determine the first timing advance according to the above relationship (2) at the second moment. TA_new Indicates a first timing advance. The first timing advance is based on N before the second moment. TA_old The component of the first timing advance may be zero or the component of the first timing advance may be less than 100% of the first timing advance, such as preconfigured to 40% or other values.

[0116] Specifically, the terminal device can determine the TA adjustment amount through the following equations (3) and (4). TA =(N TA_new +N TA,UE-specific +N TA,common +N TA,offset )×T c ;(3)

[0117] Among them, N TA,UE-specific 、N TA,common 、N TA,offset and T c Please refer to the explanation in relational formula (1) for understanding, and the present embodiment will not elaborate on this. TA_new It can be understood as the N determined by the terminal device at the first moment TA , the N TA_new The following relationship (4) is satisfied.

[0118] The N TA_old is the first timing advance, the α×N TA_old represents the component of the first timing advance, 0≤α<1, the T A is the timing advance determined based on the first TAC, and μ is a coefficient determined based on the subcarrier spacing corresponding to the terminal device. Optionally, when α is equal to 0, the relationship (4) can also be replaced by: or, Optionally, when α is equal to 0, S402 can also be understood as the terminal device determining the TA adjustment amount according to the first TAC, and not introducing the consideration of the first timing advance when determining the TA adjustment amount according to the first TAC, N TA_old =0.

[0119] For ease of description, the embodiment of the present application uses a first parameter to indicate information updated within a first time period. In Figure 4, before S401, it is illustrated that the first parameter is updated within the first time period, or it can be understood that: the first parameter includes one or more information of the positioning information of the terminal device, the ephemeris information of the service satellite, and the public timing advance TA.

[0120] Optionally, the content included in the first parameter may be different in different communication scenarios. Examples of some scenarios are as follows:

[0121] In scenario 1, when the serving satellite is a geostationary Earth orbit (GEO) satellite, the error compensation corresponding to the update of the terminal device's positioning information is primarily included. Therefore, the first parameter may only include the positioning information of the terminal device. In specific implementation, upon receiving the first TAC after updating the positioning information, the terminal device may determine the TA adjustment amount in accordance with S402.

[0122] Scenario 2: When the serving satellite is a low Earth orbit (LEO) satellite and the terminal device is stationary, the error compensation for updating the serving satellite's ephemeris information is primarily performed. Therefore, the first parameter may only include the ephemeris information of the terminal device. In specific implementation, upon receiving the first TAC after obtaining the updated serving satellite's ephemeris information, the terminal device may determine the TA adjustment amount in accordance with S402.

[0123] Scenario 3: When the service satellite is a low-orbit LEO satellite and the terminal device is in a mobile state, it may include error compensation for the ephemeris information of the service satellite and the positioning information update of the terminal device. The terminal device can determine that the first parameter includes one or more of the ephemeris information of the service satellite and the positioning information of the terminal device based on parameters related to the positioning information (such as the moving speed, moving range, positioning accuracy, and positioning error of the terminal device) and the ephemeris information of the service satellite obtained (such as the orbital altitude of the service satellite, the accuracy information of the ephemeris, the validity period of the ephemeris, and the error of the ephemeris). Some examples are as follows:

[0124] In Example 1, when the terminal device's moving speed is greater than a first speed threshold, or the accuracy of the terminal device's estimated positioning information is less than a first accuracy threshold, the first parameter includes the terminal device's positioning information and the serving satellite's ephemeris information. The first speed threshold may be predefined or configured, or the serving satellite may indicate the first speed threshold to the terminal device; the first accuracy threshold may be predefined or configured, or the serving satellite may indicate the first accuracy threshold to the terminal device. In specific implementations, upon receiving the first TAC after obtaining updated serving satellite ephemeris information and updated positioning information, the terminal device may determine the TA adjustment amount in accordance with S402.

[0125] Example 2: When the moving speed of the terminal device is less than the second speed threshold, or the accuracy of the terminal device's estimated positioning information is greater than the second accuracy threshold, it indicates that the error compensation for updating the terminal device's positioning information is small. In this case, the first parameter may only include the ephemeris information of the serving satellite. The second speed threshold may be predefined or configured, or the serving satellite may indicate the first speed threshold to the terminal device. The second speed threshold is less than or equal to the first speed threshold. The second accuracy threshold may be predefined or configured, or the serving satellite may indicate the first accuracy threshold to the terminal device. The second accuracy threshold is greater than or equal to the first accuracy threshold. In specific implementation, the terminal device may determine the TA adjustment amount in accordance with S402 when receiving the first TAC after obtaining the updated ephemeris information of the serving satellite.

[0126] In Example 3, when the orbital altitude of the serving satellite is lower than a first altitude threshold, the first parameter includes ephemeris information of the serving satellite. The first altitude threshold may be predefined or configured, or the serving satellite may indicate the first altitude threshold to the terminal device. In a specific implementation, the terminal device may determine the TA adjustment amount in accordance with S402 upon receiving the first TAC after obtaining updated ephemeris information of the serving satellite.

[0127] In Example 4, when the orbital altitude of the serving satellite is higher than a second altitude threshold, the first parameter includes positioning information of the terminal device. The second altitude threshold may be predefined or configured, or the serving satellite may indicate the second altitude threshold to the terminal device. The second altitude threshold is greater than or equal to the first altitude threshold. In a specific implementation, upon receiving the first TAC after updating the positioning information, the terminal device may determine the TA adjustment amount in accordance with S402.

[0128] In Example 5, when the moving speed of the terminal device is greater than a first speed threshold and the orbital altitude of the serving satellite is greater than a second altitude threshold, the first parameter includes positioning information of the terminal device. In a specific implementation, the terminal device may determine the TA adjustment amount in accordance with S402 upon receiving the first TAC after updating the positioning information.

[0129] In Example 6, when the moving speed of the terminal device is less than a second speed threshold and the orbital altitude of the serving satellite is less than a first altitude threshold, the first parameter includes ephemeris information of the serving satellite. In a specific implementation, the terminal device may determine the TA adjustment amount in accordance with S402 upon receiving the first TAC after obtaining updated ephemeris information of the serving satellite.

[0130] In Example 7, when the error corresponding to the ephemeris information of the serving satellite is less than a first error threshold, the first parameter includes the positioning information of the terminal device. Optionally, the first error threshold may be predefined or configured, or the serving satellite may indicate the first error threshold to the terminal device. In a specific implementation, upon receiving the first TAC after updating the positioning information, the terminal device may determine the TA adjustment amount in accordance with S402.

[0131] The error corresponding to the ephemeris information primarily includes the initial error of the ephemeris indicated by the serving satellite and the error derived from the ephemeris derived by the terminal device. In one possible implementation, the accuracy of the ephemeris derived by the terminal device is high, resulting in a smaller error in the derived ephemeris, potentially enabling the error corresponding to the ephemeris information to be less than a first error threshold. Optionally, the terminal device may also report the accuracy of the derived ephemeris or an error model used to determine the derived error to the serving satellite. The serving satellite may configure the validity period or update period of the ephemeris information for the terminal device based on the information reported by the terminal device. The terminal device may then determine the time to read the ephemeris information broadcast by the serving satellite based on the validity period or update period of the ephemeris information, thereby reducing the impact of the terminal device's reading of ephemeris information or positioning information updates on the determination of the TA adjustment amount.

[0132] In Example 8, when the error corresponding to the positioning information of the terminal device is less than a second error threshold, the first parameter includes the ephemeris information of the terminal device. Optionally, the second error threshold may be predefined or configured, or the serving satellite may indicate the second error threshold to the terminal device. In a specific implementation, the terminal device may determine the TA adjustment amount in accordance with S402 upon receiving the first TAC after obtaining updated ephemeris information from the serving satellite.

[0133] The terminal device can determine the accuracy and error of the positioning information by itself. Optionally, the terminal device can also report the error (which can be a specific value or an error range) corresponding to the positioning information to the serving satellite.

[0134] Furthermore, the terminal device may further perform step S403:

[0135] S403: The terminal device communicates with the serving satellite according to the TA adjustment amount.

[0136] Specifically, the TA adjustment amount corresponds to the first TAC received by the terminal device in S401. The terminal device can communicate with the serving satellite according to the TA adjustment amount until the next TAC is received and the TA adjustment amount is updated.

[0137] The above method provided in the embodiment of the present application uses the positioning information update of the terminal device and / or the ephemeris update of the service satellite as trigger conditions in a specific satellite communication scenario, reduces the error compensation of the closed-loop TA adjustment mechanism part, can reduce the error jump when determining the TA adjustment amount, and at the same time ensure the accuracy of the TA adjustment amount.

[0138] FIG5 illustrates a second TA determination method, which mainly includes the following process.

[0139] S501: A service satellite sends first information to a terminal device.

[0140] The first information indicates the periodic information of the random sequence sent by the terminal device. For example, the first information indicates I moments at which the terminal device sends the random access sequence, where the interval between each two moments in the I moments is the same, and I is a positive integer greater than 1.

[0141] In one possible implementation, the terminal device can report the valid time of the positioning information to the service satellite, and the service satellite configures the periodic information of the aforementioned random access sequence according to the valid time of the positioning information of the terminal device, for example, the interval between each two moments in I moments is less than or equal to the valid time of the positioning information of the terminal device.

[0142] S502: The terminal device sends a random access sequence at the i-th moment among the I moments, and receives a second timing advance command TAC from the serving satellite at a third moment.

[0143] The third moment is a moment between the i-th moment and the i+1-th moment, and i is a positive integer from 1 to I-1. Optionally, the second TAC is the first TAC received by the terminal device after the i-th moment.

[0144] Furthermore, it is understood that the serving satellite may periodically transmit a PDCCH (e.g., a PDCCH order PARCH) to trigger the terminal device to transmit a random access sequence. For example, the serving satellite may transmit a PDCCH order PARCH during the period between time i-1 and time i, thereby triggering the terminal device to transmit a random access sequence at time i.

[0145] S503: The terminal device determines a TA adjustment amount according to the second TAC.

[0146] Corresponding to the description in formula (1), it can be understood that when the terminal device sends the random access sequence at the i-th moment, N TA Therefore, when the terminal device receives the second TAC to determine the TA adjustment amount, it will not accumulate the TA corresponding to the historical TAC.

[0147] Specifically, the terminal device determines the TA adjustment amount T according to the second TAC TA Satisfies the following relations (5) and (6): T TA =(N TA +N TA,UE-specific +N TA,common +N TA,offset )×T c ;(5)

[0148] Among them, N TA,UE-specific 、N TA,common 、N TA,offset and T c Please refer to the explanation in relational formula (1) for understanding, and the present embodiment will not elaborate on this. TA is the timing advance determined by the terminal device based on the second TAC, the N TA The following relationship (6) is satisfied.

[0149] Here, μ is a coefficient determined based on the subcarrier spacing corresponding to the terminal device.

[0150] S504: The terminal device communicates with the serving satellite according to the TA adjustment amount.

[0151] Specifically, the TA adjustment amount corresponds to the second TAC received by the terminal device in S502. The terminal device can communicate with the serving satellite according to the TA adjustment amount until the next TAC of the second TAC is received and the TA adjustment amount is updated.

[0152] The above method provided in the embodiment of the present application utilizes the characteristic that the historical TAC accumulates to zero when the terminal device sends a random access sequence, configures the periodic sending of random access sequences, and realizes the periodic multiple reduction of the error compensation of the closed-loop TA adjustment mechanism part, which can reduce the error jump when determining the TA adjustment amount, and at the same time ensure the accuracy of the TA adjustment amount. For example, for the communication scenario of GEO satellites, TA is mainly caused by the error of the positioning information (GNSS information) of the terminal device. The service satellite configures enough PDCCH ordered PRACH according to the effective duration of the positioning information of the terminal device to correct the TA error accumulated by TAC. For the LEO scenario, the TA error is mainly caused by the initial error of the service satellite's ephemeris. The service satellite can correct the TA error accumulated by TAC by sending enough PDCCH ordered PRACH.

[0153] FIG6 illustrates a third TA determination method, which includes the following process.

[0154] S601: When the terminal device determines to update the first parameter, the terminal device sends second information to the serving satellite.

[0155] The first parameter may be one or more of the following information: positioning information of the terminal device, ephemeris information of the serving satellite, and public timing advance (TA) information. The second information is used to request configuration information of the random access sequence, for example, the second information is used to request the serving satellite to send a PDCCH order PRACH.

[0156] Optionally, the second information sent by the terminal device may be uplink (UL)-medium access control (MAC)-control element (CE) signaling, referred to as UL MAC CE. The terminal device may also implement an update operation on the first parameter through the UL MAC CE, that is, the terminal device may update the first parameter after sending the UL MAC CE. In such a design, the serving satellite configures the PRACH only at the request of the terminal device, which can save PDCCH / PRACH resources.

[0157] Accordingly, if the terminal device receives configuration information of the random access sequence, such as PDCCH order PRACH, the random access sequence is sent to the serving satellite, that is, the terminal device performs S602 after S601. If the terminal device does not receive configuration information of the random access sequence, such as PDCCH order PRACH, the terminal device does not send the random access sequence to the serving satellite.

[0158] S602: The terminal device receives configuration information of a random access sequence and sends a random access sequence.

[0159] Accordingly, after receiving the random access sequence, the serving satellite sends a TAC to the terminal device via a RAR message. This TAC is recorded as a third TAC. For the terminal device, the third TAC is the first TAC received by the terminal device after sending the random access sequence. Specifically, the terminal device may execute the following step S603 after executing S602.

[0160] S603: The terminal device receives a third TAC and determines a TA adjustment amount according to the third TAC.

[0161] Corresponding to the description in formula (1), it can be understood that when the terminal device sends a random access sequence, N TA Therefore, when the terminal device receives the third TAC to determine the TA adjustment amount, it will not accumulate the TA corresponding to the historical TAC.

[0162] Specifically, the terminal device can determine the TA adjustment amount T according to the third TAC according to equations (5) and (6). TA It can be understood that in S603, T in equation (6) A The timing advance corresponding to the third TAC is substituted in, that is, the terminal device calculates the timing advance T corresponding to the third TAC according to equation (6). A , determine N in equation (5) TA , and then determine the TA adjustment amount based on equation (5).

[0163] Furthermore, after executing S603, the terminal device may further execute step S604:

[0164] S604: The terminal device communicates with the serving satellite according to the TA adjustment amount.

[0165] Specifically, the TA adjustment amount corresponds to the third TAC received by the terminal device in S603. The terminal device can communicate with the serving satellite according to the TA adjustment amount until the next TAC of the third TAC is received and the TA adjustment amount is updated.

[0166] In the above method provided in the embodiment of the present application, the terminal device utilizes the characteristic that the historical TAC accumulates to zero when sending a random access sequence, and requests the network side to send a random access sequence during the positioning information or ephemeris information update process to reduce the error compensation of the closed-loop TA adjustment mechanism part, which can reduce the error jump when determining the TA adjustment amount, and at the same time ensure the accuracy of the TA adjustment amount.

[0167] FIG7 illustrates a fourth TA determination method, which is mainly applied to communication scenarios where the terminal device is in a mobile state. The method includes the following process.

[0168] S701: The satellite sends third information to the terminal device.

[0169] The third information indicates a requirement for the mobility status of the terminal device, such as indicating a first condition that the mobility status of the terminal device must satisfy. Optionally, the satellite may broadcast the third information, and the terminal device may obtain the third information by monitoring the broadcast message. The satellite may be a LEO satellite or a GEO satellite.

[0170] Specifically, the movement state of the terminal device may include parameters such as the movement speed of the terminal device, the movement range of the terminal device within a unit time, and the movement direction of the terminal device.

[0171] In a first possible implementation, the first condition indicated by the third information is that the terminal device's moving speed is less than or equal to a third speed threshold. The third information may include the third speed threshold. For example, the satellite may determine an upper limit of the terminal device's moving speed supported by the satellite based on its orbital altitude, i.e., determine the third speed threshold. For another example, the satellite may determine the third speed threshold based on its orbital altitude and the elevation angle information from the terminal device to the satellite. It is understood that different elevation angle information may correspond to different values ​​for the third speed threshold.

[0172] In a second possible implementation, the first condition indicated by the third information is that the terminal device's movement speed falls within a first speed range, and the third information may include the first speed range. For example, a satellite may determine the range of movement speeds supported by the current satellite for the terminal device based on its orbital altitude, i.e., determine the first speed range. For another example, the satellite may determine the first speed range based on its orbital altitude and the elevation angle information from the terminal device to the satellite. It is understood that different elevation angle information may correspond to different values ​​for the first speed range.

[0173] In a third possible implementation, the first condition indicated by the third information is that the range of movement of the terminal device per unit time is less than or equal to the first range of movement, and the third information may include the first range of movement. For example, the satellite may determine the upper limit of the range of movement of the terminal device supported by the current satellite per unit time based on the orbital altitude, i.e., determine the first range of movement. For another example, the satellite may determine the first range of movement based on the orbital altitude and the elevation angle information from the terminal device to the satellite. It is understandable that different elevation angle information corresponds to different values ​​of the first range of movement.

[0174] Accordingly, after receiving the third information, the terminal device can determine, based on the positioning information, whether its own mobility state meets the first condition indicated by the third information. If the mobility state meets the first condition, the terminal device initiates random access to the satellite, and maintains the mobility state meeting the first condition during the communication process after random access. If the mobility state does not meet the first condition, the terminal device does not initiate random access to the satellite. For example, FIG7 illustrates the situation where the mobility state meets the first condition through S702 and S703.

[0175] S702: The terminal device determines, based on the positioning information, that the mobile state of the terminal device meets the first condition indicated by the third information.

[0176] S703: The terminal device initiates random access to the satellite.

[0177] For example, the terminal device may send a random access sequence on a random access resource configured by the satellite, and the satellite may return a RAR message including a TAC. The terminal device may then determine the TA adjustment amount used for communicating with the satellite according to the scheme described in equation (1). This embodiment of the present application does not elaborate on this.

[0178] The above method provided in the embodiment of the present application is applied to the communication scenario of the mobile terminal. By controlling the moving speed or moving range of the terminal device, the error compensation for the positioning information update is reduced, that is, the error compensation of the open-loop TA adjustment mechanism is reduced, which can reduce the error jump when determining the TA adjustment amount, and at the same time ensure the accuracy of the TA adjustment amount.

[0179] Based on the same concept, referring to FIG8 , an embodiment of the present application provides a communication device 800, which includes a processing module 801 and a communication module 802. The communication device 800 can be a terminal device, or a communication device applied to or used in conjunction with a terminal device, capable of implementing a communication method executed on the terminal device side; or the communication device 800 can be a network device (such as a service satellite for a terminal device), or a communication device applied to or used in conjunction with a network device, capable of implementing a communication method executed on the network device side.

[0180] The communication module may also be referred to as a transceiver module, transceiver, transceiver, or transceiver device. The processing module may also be referred to as a processor, processing board, processing unit, or processing device. Optionally, the communication module is used to perform the sending and receiving operations on the terminal device side or the network device side in the above method. The device in the communication module that implements the receiving function can be considered a receiving unit, and the device in the communication module that implements the sending function can be considered a sending unit. That is, the communication module includes a receiving unit and a sending unit.

[0181] When the communication device 800 is applied to a terminal device, the processing module 801 can be used to implement the processing function of the terminal device described in the embodiments shown in Figures 4 to 7, and the communication module 802 can be used to implement the transceiver function of the terminal device described in the embodiments shown in Figures 4 to 7.

[0182] When the communication device 800 is applied to a network device, the processing module 801 can be used to implement the processing function of the network device described in the embodiments shown in Figures 4 to 7, and the communication module 802 can be used to implement the transceiver function of the network device described in the embodiments shown in Figures 4 to 7.

[0183] In addition, it should be noted that the aforementioned communication module and / or processing module can be implemented through virtual modules, for example, the processing module can be implemented through a software functional unit or a virtual device, and the communication module can be implemented through a software function or a virtual device. Alternatively, the processing module or the communication module can also be implemented through a physical device. For example, if the communication device is implemented using a chip / chip circuit, the communication module can be an input / output circuit and / or a communication interface that performs input operations (corresponding to the aforementioned receiving operations) and output operations (corresponding to the aforementioned sending operations); the processing module is an integrated processor, microprocessor, or integrated circuit.

[0184] The division of modules in the embodiments of the present application is illustrative and is merely a logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in the various embodiments of the present application may be integrated into a single processor, or may exist physically separately, or two or more modules may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or software functional modules.

[0185] Based on the same technical concept, the embodiment of the present application further provides a communication device 900. For example, the communication device 900 can be a chip or a chip system. Optionally, in the embodiment of the present application, the chip system can be composed of a chip, or can include a chip and other discrete devices.

[0186] The communication device 900 can be used to implement the functions of any network element in the communication system described in the aforementioned embodiments. The communication device 900 may include at least one processor 910, which is coupled to a memory. Optionally, the memory may be located within the communication device, the memory may be integrated with the processor, or the memory may be located outside the communication device. For example, the communication device 900 may also include at least one memory 920. The memory 920 stores the necessary computer programs, computer programs or instructions and / or data for implementing any of the aforementioned embodiments; the processor 910 may execute the computer program stored in the memory 920 to complete the method in any of the aforementioned embodiments.

[0187] The communication device 900 may also include a communication interface 930, and the communication device 900 can exchange information with other devices through the communication interface 930. Exemplarily, the communication interface 930 can be a transceiver, a circuit, a bus, a module, a pin, or other types of communication interfaces. When the communication device 900 is a chip-type device or circuit, the communication interface 930 in the communication device 900 can also be an input-output circuit that can input information (or receive information) and output information (or send information). The processor is an integrated processor or microprocessor or integrated circuit or logic circuit, and the processor can determine output information based on the input information.

[0188] The coupling in the embodiments of the present application is an indirect coupling or communication connection between devices, units, or modules, which can be electrical, mechanical, or other forms, and is used for information exchange between devices, units, or modules. The processor 910 may operate in conjunction with the memory 920 and the communication interface 930. The specific connection medium between the processor 910, memory 920, and communication interface 930 is not limited in the embodiments of the present application.

[0189] Optionally, referring to FIG9 , the processor 910, the memory 920, and the communication interface 930 are interconnected via a bus 940. The bus 940 may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus may be classified as an address bus, a data bus, a control bus, etc. For ease of illustration, FIG9 shows only one thick line, but this does not mean that there is only one bus or only one type of bus.

[0190] In the embodiments of the present application, the processor may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component, and may implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of the present application. A general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of the present application may be directly implemented as being executed by a hardware processor, or may be executed by a combination of hardware and software modules in the processor.

[0191] In an embodiment of the present application, the memory may be a non-volatile memory, such as a hard disk drive (HDD) or a solid-state drive (SSD), etc., or a volatile memory (volatile memory), such as a random-access memory (RAM). The memory is any other medium that can be used to carry or store a desired program code in the form of an instruction or data structure and can be accessed by a computer, but is not limited thereto. The memory in the embodiment of the present application may also be a circuit or any other device that can implement a storage function, for storing program instructions and / or data.

[0192] In one possible implementation, the communication device 900 can be applied to a network device (such as a service satellite of a terminal device). Specifically, the communication device 900 can be a network device, or a device that can support a network device and implement the functions of the network device in any of the above-mentioned embodiments. The memory 920 stores a computer program (or instruction) and / or data that implements the functions of the network device in any of the above-mentioned embodiments. The processor 910 can execute the computer program stored in the memory 920 to complete the method executed by the network device in any of the above-mentioned embodiments. Applied to a network device, the communication interface in the communication device 900 can be used to interact with the terminal device, send information to the terminal device, or receive information from the terminal device.

[0193] In another possible implementation, the communication device 900 can be applied to a terminal device. Specifically, the communication device 900 can be a terminal device, or a device that can support the terminal device and implement the functions of the terminal device in any of the above-mentioned embodiments. The memory 920 stores a computer program (or instruction) and / or data that implements the functions of the terminal device in any of the above-mentioned embodiments. The processor 910 can execute the computer program stored in the memory 920 to complete the method executed by the terminal device in any of the above-mentioned embodiments. Applied to a terminal device, the communication interface in the communication device 900 can be used to interact with a network device, send information to the network device, or receive information from the network device.

[0194] Since the communication device 900 provided in this embodiment can be applied to a network device to implement the method executed by the network device, or applied to a terminal device to implement the method executed by the terminal device, the technical effects that can be obtained can be referred to the above method examples and will not be repeated here.

[0195] Based on the above embodiments, an embodiment of the present application provides a communication system, including a network device and a terminal device, wherein the network device and the terminal device can implement the method provided in the embodiment shown in Figure 3, Figure 5 or Figure 6.

[0196] The technical solutions provided in the embodiments of the present application can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, they can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a terminal device, a network device, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more available media integrated therein. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a digital video disc (DVD)), or a semiconductor medium.

[0197] In the embodiments of the present application, under the premise that there is no logical contradiction, the embodiments may reference each other, for example, the methods and / or terms between method embodiments may reference each other, for example, the functions and / or terms between device embodiments may reference each other, for example, the functions and / or terms between device embodiments and method embodiments may reference each other.

[0198] Obviously, those skilled in the art may make various changes and modifications to the embodiments of the present application without departing from the scope of the embodiments of the present application. Thus, if these modifications and variations of the embodiments of the present application fall within the scope of the claims of the embodiments of the present application and their equivalents, the embodiments of the present application are intended to include these modifications and variations.

Claims

1. A method for determining a timing advance TA, characterized in that: include: The terminal device receives a first timing advance command TAC at a first moment; If the first parameter is updated within a first time period before the first moment, the terminal device determines a TA adjustment amount according to a component of a first timing advance and the first TAC; wherein the first timing advance is determined by the terminal device at the second moment, and the first time period is a time period from the second moment to the first moment; the first parameter includes one or more of the following information: positioning information of the terminal device, ephemeris information of a service satellite, and a public timing advance TA; The terminal device communicates with the serving satellite according to the TA adjustment amount.

2. The method according to claim 1, characterized in that The service satellite is a geostationary orbit GEO satellite, and the first parameter includes positioning information of the terminal device.

3. The method according to claim 1, characterized in that The service satellite is a low-orbit LEO satellite, the terminal device is in a stationary state, and the first parameter includes ephemeris information of the service satellite.

4. The method according to claim 1, characterized in that The service satellite is a low-orbit LEO satellite, the terminal device is in a mobile state, and the first parameter includes the positioning information of the terminal device and / or the ephemeris information of the service satellite.

5. The method according to claim 4, characterized in that: If the moving speed of the terminal device is greater than a first speed threshold, the first parameter includes positioning information of the terminal device and ephemeris information of the service satellite; or, If the moving speed of the terminal device is less than a second speed threshold, the first parameter includes ephemeris information of the service satellite; or, If the orbital altitude of the service satellite is lower than a first altitude threshold, the first parameter includes ephemeris information of the service satellite; or, If the orbital altitude of the service satellite is higher than a second altitude threshold, the first parameter includes positioning information of the terminal device; or, If the moving speed of the terminal device is greater than a first speed threshold, and the orbital altitude of the service satellite is higher than a second altitude threshold, the first parameter includes positioning information of the terminal device; or, If the moving speed of the terminal device is less than a second speed threshold, and the orbital altitude of the service satellite is lower than a first altitude threshold, the first parameter includes ephemeris information of the service satellite; or, If the error corresponding to the ephemeris information of the service satellite is less than a first error threshold, the first parameter includes positioning information of the terminal device; or, If the error corresponding to the positioning information of the terminal device is less than a second error threshold, the first parameter includes the ephemeris information of the terminal device.

6. The method according to claim 5, characterized in that Before determining the TA adjustment amount, it also includes: First information is received from the serving satellite, where the first information is used to indicate one or more of the following: the first speed threshold, the second speed threshold, the first altitude threshold, the second altitude threshold, the first error threshold, and the second error threshold.

7. The method according to any one of claims 1 to 6, characterized in that: The TA adjustment amount T TA Satisfies the following relationship: T TA =(N TA_new +N TA,UE-specific +N TA,common +N TA,offset )×T c ; Among them, the The N TA_old is the first timing advance, the α×N TA_old represents the component of the first timing advance, 0≤α<1, the T A is a timing advance determined based on the first TAC, and μ is a coefficient determined based on the subcarrier spacing corresponding to the terminal device; The N TA,UE-specific is a timing advance determined based on the ephemeris information of the service satellite and the positioning information of the terminal device; the N TA,common is the timing advance associated with the public TA information; the N TA,offset is the preconfigured timing offset; T c The minimum time unit.

8. A method for determining a timing advance TA, characterized in that: include: First information received by a terminal device, the first information indicating I moments at which the terminal device sends a random access sequence, the interval between every two moments in the I moments being the same, and I being a positive integer greater than 1; The terminal device sends a random access sequence at the i-th moment in the I moments, and receives a second timing advance command at the third moment. Let TAC; wherein the third moment is the moment between the i-th moment and the i+1-th moment, and i is a positive integer from 1 to I-1; The terminal device determines a TA adjustment amount according to the second TAC; wherein the second timing advance amount is determined by the terminal device before the third moment; The terminal device communicates with the serving satellite according to the TA adjustment amount.

9. The method according to claim 8, characterized in that The second TAC is the first TAC received by the terminal device after the i-th moment.

10. The method according to claim 8 or 9, characterized in that The TA adjustment amount T TA Satisfies the following relationship: T TA =(N TA +N TA,UE-specific +N TA,common +N TA,offset )×T c ; Among them, the The T A is a timing advance determined based on the second TAC, and μ is a coefficient determined based on the subcarrier spacing corresponding to the terminal device; The N TA,UE-specific is a timing advance determined based on the ephemeris information of the service satellite and the positioning information of the terminal device; the N TA,common is the timing advance associated with the public TA information; the N TA,offset is the preconfigured timing offset; T c The minimum time unit.

11. The method according to any one of claims 8 to 10, characterized in that Before the terminal device receives the first information, the method further includes: The terminal device sends second information to the service satellite, where the second information is used to indicate the valid time of the positioning information of the terminal device, and the second information is used to determine the interval between every two moments in the I moments.

12. A method for determining a timing advance TA, characterized in that: include: When the terminal device determines to update the first parameter, the terminal device sends second information to the serving satellite, where the second information is used to request configuration information of the random access sequence; wherein the first parameter includes one or more of the following information: positioning information of the terminal device, ephemeris information of the serving satellite, and public timing advance TA information; The terminal device sends a random access sequence according to the received configuration information of the random access sequence; The terminal device receives a third timing advance command TAC, and determines a TA adjustment amount according to the third TAC; wherein the third TAC is the first TAC received by the terminal device after sending a random access sequence; The terminal device communicates with the serving satellite according to the TA adjustment amount.

13. The method according to claim 12, characterized in that The TA adjustment amount T TA Satisfies the following relationship: T TA =(N TA +N TA,UE-specific +N TA,common +N TA,offset )×T c ; Among them, the The T A is a timing advance determined based on the third TAC, and μ is a coefficient determined based on the subcarrier spacing corresponding to the terminal device; The N TA,UE-specific is a timing advance determined based on the ephemeris information of the service satellite and the positioning information of the terminal device; the N TA,common is the timing advance associated with the public TA information; the N TA,offset is the preconfigured timing offset; T c The minimum time unit.

14. A communication device, characterized in that: The method comprises a module for executing the method according to any one of claims 1 to 7, or a module for executing the method according to any one of claims 8 to 11, or a module for executing the method according to any one of claims 12 to 13.

15. A communication device, characterized in that: include: at least one processor and memory; The memory is used to store computer programs or instructions; The at least one processor is configured to execute the computer program or instructions to implement the method according to any one of claims 1 to 7, or the method according to any one of claims 8 to 11, or the method according to any one of claims 12 to 13.

16. A communication device, characterized in that: include: Logic circuits and input and output interfaces; The input and output interface is used to communicate with modules outside the communication device; The logic circuit is used to execute a computer program to enable the communication device to execute the method according to any one of claims 1 to 7, or the method according to any one of claims 8 to 11, or the method according to any one of claims 12 to 13.

17. A communication system, characterized in that: The communication system includes a terminal device and a satellite, wherein the terminal device is used to execute the method as described in any one of claims 1 to 7, or to execute the method as described in any one of claims 8 to 11, or to execute the method as described in any one of claims 12 to 13; and the satellite is used to communicate with the terminal.

18. A computer-readable storage medium, characterized in that: The storage medium stores a computer program or an instruction. When the computer program or the instruction is executed by the communication device, the method according to any one of claims 1 to 13 is implemented.

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