Timing advance updating method, terminal device, chip system and medium

Abstract

The present application provides a timing advance updating method, terminal device, chip system and medium, which are applied to the field of satellite communications. The terminal device updates the timing advance by itself, which can not only improve the updating efficiency of the timing advance, but also reduce the signaling overhead. The method includes: the terminal device determines the time deviation, and then determines the second timing advance according to the time deviation and the first timing advance. Among them, the time deviation is the deviation value of the starting position of the first downlink channel in the time domain compared to the starting position of the second downlink channel in the time domain. The first downlink channel is the downlink receiving channel of the terminal device at the current moment, and the second downlink channel is the downlink receiving channel of the terminal device when the terminal device and the satellite base station complete the uplink and downlink synchronization through the first timing advance. The first timing advance is the timing advance currently used by the terminal device. After determining the second timing advance, the terminal device performs uplink transmission to the satellite base station according to the second timing advance.

Description

Technical Field

[0001] The present application belongs to the field of satellite communications, and in particular relates to a timing advance updating method, terminal equipment, chip system and medium. Background Art

[0002] Satellite communications and other non-terrestrial networks (NTN) have significant advantages such as global coverage, long-distance transmission, flexible networking, convenient deployment and no geographical restrictions. They have been widely used in many fields such as maritime communications, positioning navigation, disaster relief, scientific experiments, video broadcasting and earth observation. The terrestrial network and satellite network are integrated with each other, complementing each other's strengths and weaknesses, and jointly constitute a global seamless coverage of the sea, land, air, space and ground integrated integrated communication network to meet the various business needs of users everywhere.

[0003] In satellite communication systems, due to the fast satellite movement speed and the long propagation distance of satellite-to-ground communication, the uplink timing advance (TA) of the ground terminal may have time deviation, causing inter-carrier interference (ICI) or even interference between multiple users, thereby reducing the demodulation performance of the system. Summary of the invention

[0004] The embodiments of the present application provide a timing advance updating method, terminal device, chip system and medium, which can improve the timing advance updating efficiency while reducing signaling overhead.

[0005] In the first aspect, a method for updating a timing advance is provided, the method comprising: a terminal device determines a time deviation, and then determines a second timing advance based on the time deviation and the first timing advance. The time deviation is a deviation value between the starting position of the first downlink channel in the time domain and the starting position of the second downlink channel in the time domain, the first downlink channel is a downlink receiving channel of the terminal device at the current moment, the second downlink channel is a downlink receiving channel of the terminal device when the terminal device and the satellite base station complete uplink and downlink synchronization through the first timing advance, and the first timing advance is the timing advance currently used by the terminal device. After determining the second timing advance, the terminal device performs uplink transmission to the satellite base station according to the second timing advance.

[0006] In the above scheme, the terminal device can update the timing advance by itself, and there is no need for the satellite base station to send a timing advance command (TAC) to update the timing advance, which can improve the updating efficiency of the timing advance and reduce the signaling overhead. Specifically, the terminal device uses the starting position of the second downlink channel in the time domain as the reference point, because the second downlink channel is the downlink receiving channel when the terminal device and the satellite base station complete the uplink and downlink synchronization, and the uplink and downlink are aligned at this time. As time goes by, the downlink channel of the terminal device will have a time deviation. The terminal device can use the starting position of the current first downlink channel in the time domain as a synchronization point and compare it with the above reference point to determine the time deviation. Further, the terminal device can update the current timing advance to the second timing advance according to the first timing advance and the time deviation. In this scheme, the first timing advance is known to the terminal device itself, so the terminal device only needs to determine the time deviation based on the downlink receiving channel, and does not need to obtain additional information (such as ephemeris information) from the network device to complete the update of the timing advance by itself.

[0007] Compared with the solution in which the satellite base station or other network equipment updates the timing advance and notifies the terminal device, the solution in the present application can update the timing advance more conveniently and quickly. Because there will be a certain transmission delay between the terminal device and the satellite base station (or other network device), the satellite base station notifies the terminal device to update the timing advance through downlink signaling, which will not only cause additional signaling overhead but also have relatively low efficiency.

[0008] On the other hand, in the satellite communication scenario, the transmission delay is relatively large. When the terminal device receives the new timing advance sent by the satellite base station, a period of time may have passed, that is, the effective time of the timing advance will be affected.

[0009] On the other hand, a satellite usually serves multiple terminal devices. As the satellite moves at high speed, the timing advance of a large number of terminal devices may need to be frequently updated, which will occupy more resources of the satellite base station. Distributing the task of updating the timing advance to each terminal device can reduce the resource consumption on the satellite base station side. For each terminal device, it only needs to track and update its own timing advance, and the resources consumed are negligible.

[0010] In summary, in the above scheme provided in the embodiment of the present application, the terminal device can use its own known information to complete the update of the timing advance by itself, which can improve the updating efficiency of the timing advance, reduce the signaling overhead between the terminal device and the satellite base station, and also increase the effective time of the timing advance, as well as reduce resource consumption on the network side.

[0011] In combination with the first aspect, in some possible implementations of the first aspect, the terminal device determines the second timing advance based on the time deviation and the first timing advance, including: the terminal device determines the uplink and downlink transmission deviation, the uplink and downlink transmission deviation is the time difference between the moment when the terminal device receives the downlink signal through the first downlink channel and the moment when the terminal device next sends the uplink signal; determine the second timing advance based on the uplink and downlink transmission deviation, the time deviation and the first timing advance.

[0012] Based on the above scheme, the uplink and downlink transmission deviation refers to the time difference between uplink transmission and downlink transmission. If the terminal device performs uplink transmission immediately after receiving the downlink signal, the uplink transmission deviation is 0; if the terminal device waits for a period of time before performing uplink transmission after receiving the downlink signal, the uplink and downlink transmission deviation is the waiting time. Since the movement of the satellite during the period corresponding to the uplink and downlink transmission deviation may cause the new timing advance to become invalid again, when determining the second timing advance, considering the influence of the uplink and downlink transmission deviation can improve the accuracy of the calculated second timing advance.

[0013] In combination with the first aspect, in some possible implementations of the first aspect, a second timing advance is determined based on the uplink and downlink transmission deviation, the time deviation, and the first timing advance, including: when the uplink and downlink transmission deviation is less than or equal to the first threshold, determining the second timing advance as the sum of the first timing advance and the time deviation.

[0014] Based on the above scheme, the terminal device can determine the uplink and downlink transmission deviation by itself, and when the uplink and downlink transmission deviation is relatively small (less than or equal to the first threshold), the influence of the uplink and downlink transmission deviation is ignored, and only the value of the time deviation needs to be compensated for the first timing advance to obtain the updated second timing advance. This implementation method takes into account the influence of the uplink and downlink transmission deviation on the timing advance, but does not require corresponding compensation for the timing advance as long as there is an uplink and downlink transmission deviation. Instead, when the uplink and downlink transmission deviation is less than the preset first threshold, the influence of the uplink and downlink transmission deviation is ignored, which can reduce the complexity of calculation and reduce resource consumption.

[0015] In combination with the first aspect, in some possible implementations of the first aspect, when the uplink and downlink transmission deviation is less than or equal to the first threshold, the second timing advance is determined to be the sum of the first timing advance and the time deviation, including: when the uplink and downlink transmission deviation is less than or equal to the first threshold, and the time deviation is greater than or equal to the second threshold, the second timing advance is determined to be the sum of the first timing advance and the time deviation.

[0016] Based on the above scheme, the terminal device does not need to update the first timing advance every time after calculating a time deviation. Because it is possible that the transmission delay between the satellite base station and the terminal device changes slightly within a calculation cycle, the change in the timing advance may not meet the update requirements at this time, so the timing advance may not be updated temporarily to reduce resource consumption. On the contrary, if the transmission delay between the satellite base station and the terminal device changes greatly within a calculation cycle, resulting in the change in the timing advance meeting the update requirements, the first timing advance needs to be updated to the second timing advance. In the scheme provided in the embodiment of the present application, the size of the time deviation can be used to measure whether the timing advance needs to be updated. On the one hand, the time deviation is a value that has been calculated by the terminal device and does not require an additional calculation process. On the other hand, the time deviation can be used to characterize the change in transmission time or the change in timing advance.

[0017] In combination with the first aspect, in some possible implementations of the first aspect, a second timing advance is determined based on the uplink and downlink transmission deviation, the time deviation and the first timing advance, including: when the uplink and downlink transmission deviation is greater than a first threshold, determining the second timing advance as the sum of the first timing advance, the time deviation and the timing advance deviation, the timing advance deviation being the deviation value of the timing advance of the terminal device caused by the uplink and downlink transmission deviation.

[0018] Based on the above scheme, when the uplink and downlink transmission deviation is greater than the first threshold, it is necessary to consider the impact of the uplink and downlink transmission deviation on the timing advance. At this time, the second timing advance is determined to be the sum of the first timing advance, the time deviation and the timing advance deviation, and the timing advance deviation is the deviation value of the timing advance of the terminal device caused by the uplink and downlink transmission deviation. That is, the new timing advance (i.e., the second timing advance) is obtained by compensating the original timing advance (i.e., the first timing advance) for the uplink and downlink deviation (i.e., the time deviation) and the deviation of the timing advance caused by the uplink and downlink transmission deviation (i.e., the timing advance deviation).

[0019] In this implementation, the terminal device can determine the uplink and downlink transmission deviation by itself, and when the uplink and downlink transmission deviation is relatively large (greater than the first threshold), the influence of the uplink and downlink transmission deviation on the timing advance is considered, and it is necessary to compensate the value of the time deviation for the first timing advance, and it is also necessary to compensate for the timing advance deviation caused by the uplink and downlink transmission deviation, so as to obtain the updated second timing advance. This implementation considers the influence of the uplink and downlink transmission deviation on the timing advance, and additionally compensates for the timing advance deviation caused by the uplink and downlink transmission deviation when updating the timing advance, so as to improve the accuracy of the calculated timing advance and increase the effective time of the updated timing advance.

[0020] In combination with the first aspect, in some possible implementations of the first aspect, when the uplink and downlink transmission deviation is greater than a first threshold, the second timing advance is determined to be the sum of the first timing advance, the time deviation, and the timing advance deviation, including: when the uplink and downlink transmission deviation is greater than the first threshold, and the sum of the time deviation and the timing advance deviation is greater than or equal to a third threshold, the second timing advance is determined to be the sum of the first timing advance, the time deviation, and the timing advance deviation.

[0021] Based on the above scheme, since the size of the new timing advance is affected by the first timing advance, the time deviation and the timing advance deviation, the terminal device can determine whether the sum of the time deviation and the timing advance deviation is greater than or equal to the third threshold in addition to determining whether the uplink and downlink transmission deviation is less than or equal to the first threshold, because the sum of the time deviation and the timing advance deviation represents the change in the timing advance. The update of the timing advance is triggered only when the uplink and downlink transmission deviation is greater than the first threshold, and the sum of the time deviation and the timing advance deviation is greater than or equal to the third threshold. In this way, the number of updates to the timing advance can be reduced, and resource consumption can be reduced.

[0022] In combination with the first aspect, in some possible implementations of the first aspect, the method also includes: determining the timing advance deviation based on a third timing advance, a fourth timing advance and an uplink and downlink transmission deviation, the third timing advance being the sum of the time deviation determined by the terminal device in the current calculation cycle and the first timing advance, the fourth timing advance being the sum of the time deviation determined in the previous calculation cycle and the fifth timing advance, the fifth timing advance being the timing advance used by the terminal device in the previous calculation cycle, each calculation cycle being used to calculate the time deviation once, and the time intervals of adjacent calculation cycles being the same.

[0023] Based on the above scheme, the timing advance deviation is the deviation value of the timing advance of the terminal device caused by the uplink and downlink transmission deviation, or the deviation of the timing advance caused by the satellite movement in the time period corresponding to the uplink and downlink transmission deviation. Therefore, it can be considered that the size of the timing advance deviation depends on the size of the uplink transmission deviation and the change rate of the timing advance. The larger the uplink transmission deviation value and the higher the change rate of the timing advance, the larger the timing advance deviation. Since the value of the uplink transmission deviation has been determined, how to measure the change rate of the timing advance is the key to determining the timing advance deviation. In the above implementation scheme, the timing advance deviation is determined according to the third timing advance, the fourth timing advance and the uplink and downlink transmission deviation. Specifically, the change rate of the timing advance can be estimated based on the difference between the third timing advance and the fourth timing advance, and the size of the calculation cycle, and then the timing advance deviation can be estimated first. In this way, the deviation of the timing advance can be iteratively calculated in each calculation cycle by the terminal device in turn, without obtaining additional data from the network side, thereby improving the update efficiency of the timing advance.

[0024] In combination with the first aspect, in some possible implementations of the first aspect, the third timing advance, the fourth timing advance, the uplink and downlink transmission deviation, and the timing advance deviation satisfy the following relationship: ;in, represents the timing advance deviation, represents the third timing advance, represents the fourth timing advance, represents the time interval between adjacent calculation cycles, Indicates the uplink and downlink transmission deviation.

[0025] In combination with the first aspect, in some possible implementations of the first aspect, before the terminal device performs uplink transmission to the satellite base station according to the second timing advance, the method further includes: the terminal device reports the second timing advance to the satellite base station.

[0026] By reporting the second timing advance to the base station, the terminal device can assist the satellite base station in configuring a new timing advance.

[0027] In a second aspect, a terminal device is provided, comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and when the processor executes the computer program, the terminal device implements the steps of the method described in any one of the above-mentioned first aspects.

[0028] In a third aspect, a computer-readable storage medium is provided, which stores a computer program. When the computer program is executed by a processor, the steps of the method described in any one of the first aspects are implemented.

[0029] In a fourth aspect, a computer program product is provided. When the computer program product is executed on a terminal device, the terminal device executes any one of the methods described in the first aspect.

[0030] In a fifth aspect, a chip system is provided, which includes a processor coupled to a memory, and the processor executes a computer program stored in the memory to implement the method described in any one of the first aspects above.

[0031] The chip system may be a single chip or a chip module composed of multiple chips.

[0032] It can be understood that the beneficial effects of the second to fifth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 : is a schematic diagram of a satellite communication system 100 applicable to an embodiment of the present application;

[0034] Figure 2 : It is a schematic diagram of the timing advance;

[0035] Figure 3 :Describe an exemplary process of uplink and downlink synchronization through timing advance in a satellite communication system;

[0036] Figure 4 : Schematic diagram of the positions of the terminal equipment and the satellite when the timing advance deviation occurs;

[0037] Figure 5 : A schematic diagram of a signal offset caused by a timing advance deviation;

[0038] Figure 6 : A schematic flow chart of a method for updating a timing advance provided in an embodiment of the present application;

[0039] Figure 7 : Schematic diagram of the time deviation corresponding to the downlink channel;

[0040] Figure 8 : It is a schematic diagram of the timing advance update process;

[0041] Fig. 9 and Fig.10 : The simulation results corresponding to the timing advance updating method provided in this application;

[0042] Fig.11 : An exemplary structural diagram of a terminal device 300 applicable to the timing advance updating method provided in an embodiment of the present application;

[0043] Fig.12 : A structural schematic diagram of another simplified terminal device 400 provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0045] At present, the land mobile communication system has been relatively complete after decades of development. However, in remote areas such as deep mountains and forests, the population is sparse, the environment is harsh, and the cost of base station construction and subsequent maintenance is high. In addition, about 71% of the earth's surface area is covered by oceans, and the land area accounts for only 29%, and 30% of the land area has been desertified, making it difficult for ground communication networks to cover. In view of this, the new generation of communication technology is committed to creating a full-scenario seamless coverage network. As an emerging communication field, non-ground network systems (such as satellite communication systems) can supplement ground communication networks and effectively solve the problem of insufficient coverage of mobile cellular networks.

[0046] The technical solution of the present application can be applied to non-ground network systems such as satellite communication systems, high altitude platform station (HAPS) communications, air-to-ground (A2G) communications, and unmanned aerial vehicles (UAVs). For convenience, the present application takes a satellite communication system as an example for illustration.

[0047] Satellite communication systems can be integrated with traditional mobile communication systems. For example, the mobile communication system can be a fourth generation (4G) communication system (e.g., long term evolution (LTE) system), a worldwide interoperability for microwave access (WiMAX) communication system, a fifth generation (5G) communication system (e.g., new radio (NR) system), a sixth generation (6G) communication system, and future mobile communication systems.

[0048] See also Figure 1 , Figure 1 FIG. 1 is a schematic diagram of a satellite communication system 100 applicable to an embodiment of the present application. Figure 1As shown, the satellite can provide communication services to one or more terminal devices through multiple beams, and the number of terminals shown in the figure is only an example. The present application does not limit the specific method of communication between the satellite and the ground terminal. As an example, the satellite uses multiple beams to cover the service area, and different beams can communicate through one or more of time division, frequency division and space division.

[0049] In addition, the present application does not limit the specific types of satellites. For example, the satellites in the present application may be low-orbit satellites, medium-orbit satellites, and geostationary orbit satellites. Among them, geostationary orbit satellites and medium-orbit satellites have large transmission delays and transmission losses due to their high orbital altitudes. Low-orbit satellites have the advantages of small propagation delays and small path losses due to their relatively low orbital altitudes, and global coverage can be achieved through the collaboration of multiple satellites. With the application and development of technologies such as spot beams and frequency reuse in low-orbit satellite systems in recent years, low-orbit satellite systems have a broader space in the field of mobile communications, which is crucial to the development of communications in my country.

[0050] It can be understood that the satellite mentioned in the embodiments of the present application may also be a satellite base station, or other network-side equipment carried on a satellite, and the present application is not limited thereto.

[0051] The terminal device mentioned in the embodiments of the present application may refer to a ground terminal in a satellite communication system, including various handheld devices with wireless communication functions, vehicle-mounted devices, wearable devices, computing devices or other processing devices connected to a wireless modem, and may specifically refer to user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication equipment, user agent or user device. The terminal device may also be a satellite phone, a cellular phone, a smart phone, a wireless data card, a wireless modem, a machine type communication device, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device or a wearable device, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in remote medical, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, a terminal device in a 5G network or a future communication network, etc.

[0052] like Figure 1 As shown, satellites usually form multiple beams, each of which corresponds to a cell (or sector). Different terminal devices in the same cell have different delays in reaching the satellite. Uplink synchronization technology is required to ensure that the uplink signals of different terminal devices arrive at the satellite base station at basically the same time to ensure that the terminal devices do not interfere with each other.

[0053] Take two terminal devices (terminal device #1 and terminal device #2) as an example: Figure 1As shown, terminal device #1 and terminal device #2 are located in the same cell, but the distances between terminal device #1 and terminal device #2 and the satellite are different. Therefore, the delays when terminal device #1 and terminal device #2 communicate with the satellite are different. An uplink synchronization mechanism is required to ensure that terminal device #1 and terminal device #2 do not interfere with each other. As an exemplary scenario, in a time division duplexing (TDD) system, communication signals are divided into time slots of several lengths in time. A time slot can only be one of uplink or downlink, that is, the satellite cannot receive and send signals at the same time at a certain moment. In a TDD system, the role of uplink synchronization is not only to avoid interference between users, but also to ensure that uplink frames and downlink frames are aligned to avoid uplink and downlink interference.

[0054] In order to ensure the uplink synchronization of the receiving end, a timing advance (TA) mechanism is proposed. In order to make the uplink data packet sent by the terminal device arrive at the network device at the desired time, the transmission delay caused by the distance is estimated and the data packet is sent in advance. Specifically, the timing advance is used to indicate the time for the terminal device to perform uplink transmission. The following is a detailed introduction.

[0055] In satellite communication systems, timing advance refers to the time by which the system frame of uplink data sent by the terminal device is advanced compared to the corresponding downlink frame when performing uplink transmission. Specific examples are as follows: Figure 2 As shown. Due to the certain distance between the satellite base station and the terminal device, there is a time difference between the time when the uplink signal arrives at the satellite base station and the time when the uplink signal is sent, and an important feature of uplink transmission is the orthogonal multiple access of different users in time and frequency. In order to ensure the orthogonality of uplink transmission and avoid interference within the cell, it is required that the time when the signals from different terminal devices with the same subframe but different frequency domain resources arrive at the satellite base station is basically aligned. Therefore, from the terminal side, the timing advance is essentially a negative offset between the start time of the received downlink subframe and the time of transmitting the uplink subframe. By properly controlling the offset (i.e., timing advance) of each terminal device, the time when the uplink signal from different terminal devices arrives at the satellite base station is controlled. Simply put, for terminal devices that are far away from the satellite base station, due to the large transmission delay, the uplink signal must be sent earlier than the terminal devices that are closer to the satellite base station. It should be understood that different terminal devices have their own corresponding timing advances, and the timing advances of different terminal devices are generally different, that is, the timing advance is a terminal-level configuration.

[0056] Combine the following Figure 3 An exemplary process of performing uplink and downlink synchronization by using timing advance in a satellite communication system is described.

[0057] The terminal device needs to consider the impact of TA when performing uplink transmission. Since the propagation delay in the system is large, the range of TA values ​​is also relatively large. When the terminal device is scheduled to perform uplink transmission in a subframe, the terminal device considers the round-trip propagation delay and transmits in advance during uplink transmission, so that the uplink signal can reach the satellite base station (i.e. the network device side) on the uplink subframe corresponding to the satellite base station. Figure 3 An exemplary scenario is introduced.

[0058] like Figure 3 As shown in the figure, after the satellite base station sends the downlink signal in the downlink frame, it starts to receive the uplink signal in the uplink frame after 7 time slots (refer to the position of the satellite base station downlink frame start time slot and the satellite base station uplink frame start time slot in the figure). Assuming that the transmission delay is 6 time slots, the terminal device receives the downlink signal after 6 time slots after the satellite base station sends the downlink signal (refer to the position of the terminal device downlink frame start time slot in the figure). If the timing advance is not performed, the terminal device defaults to sending the uplink signal after 7 time slots after the downlink frame start time slot (refer to the position of the terminal device uplink frame start time slot #1 in the figure). After the transmission delay (i.e. 6 time slots), the uplink signal obviously cannot be aligned with the satellite base station uplink frame start time slot. In view of this, the terminal device uplink frame start time slot can be advanced by a TA time (refer to the position of the terminal device uplink frame start time slot #2 in the figure), and the TA here is exactly 2 times the delay (i.e. 12 time slots 0). As can be seen from the figure, the terminal device starts sending the uplink signal at the position of the uplink frame start time slot #2. After a delay, it just arrives at the satellite base station and is aligned with the satellite base station uplink frame start time slot, that is, the uplink and downlink between the terminal device and the satellite base station are aligned.

[0059] The following is a brief description of the TA generation and update process.

[0060] The satellite base station can determine the initial TA during the initial access process of the terminal device and notify the terminal device of the initial TA. For example, the terminal device uses the random access process to access the satellite base station. During this process, the satellite base station determines the initial TA based on the random access preamble and sends it to the terminal device through the TAC in the RAR message. Therefore, the terminal device can obtain the initial TA during the random access process. This process is called the "initial uplink synchronization process."

[0061] Although the terminal device completes the initial uplink synchronization during the random access process, the initial TA may become invalid over time. If the terminal device continues to use the initial TA for uplink transmission, the uplink and downlink alignment between the terminal device and the satellite base station may no longer be achieved, and inter-carrier interference (ICI) may occur between different terminal devices, or even interference between multiple users, thereby reducing the demodulation performance of the system.

[0062] Combine the following Figure 4 and Figure 5 Assume that the terminal device and the satellite base station have completed the initial uplink synchronization process, and time T has passed. The satellite has moved during time T, resulting in a change in the transmission distance between the terminal device and the satellite base station. Figure 4 In the example shown, it is assumed that the transmission distance between the terminal device and the satellite base station increases within time T, and the increased distance is recorded as l .Depend on Figure 4 It can be seen that ,in, v is the moving speed of the satellite relative to the terminal equipment, It is the angle between the satellite's moving direction and the terminal connection line.

[0063] Due to the change in transmission distance, the uplink TA of the terminal device will have time deviation, or in other words, the downlink frame of the terminal device will have time deviation. offset represents the time deviation of TA, then , where C represents the speed of light, that is, the transmission speed of the signal.

[0064] Due to the time deviation of TA, the relative position of the originally corresponding signal will be shifted, such as Figure 5 As shown, this may cause signal interference between different terminal devices and may also cause uplink and downlink interference.

[0065] Based on this, the terminal device needs to continuously update its uplink timing advance to maintain uplink synchronization. The satellite base station can control the terminal device to adjust the TA. For example, when the satellite base station detects that the deviation value of the TA is greater than the preset threshold, or the change in the transmission delay between the terminal device and the satellite base station is greater than the preset threshold, a new TA is determined based on the uplink transmission of the terminal device and notified to the terminal device through the TAC.

[0066] In other words, in order to achieve stable and reliable communication between the satellite and the ground, it is necessary to accurately estimate the TA and update the TA for the terminal device in time through the satellite base station to adjust the uplink frame time slot. However, in the satellite scenario, there are still some problems in the TA update process. The following is an exemplary explanation.

[0067] On the one hand, the satellite-to-ground transmission delay is large. Taking low-orbit satellites as an example, the orbital altitude of satellites is usually 500~2000km, and the distance between satellites and the ground is much greater than the distance between base stations and terminal devices in the ground network, resulting in a decrease in the timeliness of TA estimation in satellite-to-ground communication.

[0068] On the other hand, the transmission delay between the satellite and the ground changes greatly. The high-speed movement of the satellite causes the propagation delay between the terminal device and the satellite base station to change continuously and rapidly, which may cause the TA to fail in a very short time. For example, in the NR system, the timing error of the terminal device in the connected state cannot be greater than the timing error limit (TEL). When the subcarrier width of the synchronization signaling block (SSB) is configured to 240kHz, it only takes a few milliseconds for the TA to change beyond the timing error threshold. If in this case, the satellite base station continues to send timing advance commands to adjust the TA, it will cause huge signaling overhead.

[0069] In summary, in satellite communication scenarios, the transmission delay is large during satellite-to-ground communication, and the rate of change of the transmission delay is large, which affects the timeliness and effectiveness of uplink timing advance estimation. Frequently updating the TA for terminal devices through satellite base stations will cause relatively large signaling overhead. Therefore, how to more conveniently update the TA of terminal devices and reduce system overhead in satellite communication scenarios is a problem that needs to be solved at present.

[0070] In view of this, the embodiment of the present application provides a method for updating the timing advance executed by a terminal device. In this method, the terminal device tracks and estimates the timing advance by itself according to the time deviation of the downlink receiving channel, and updates the timing advance. There is no need for the satellite base station to send TAC to update the timing advance, which not only improves the updating efficiency of the timing advance, but also reduces the system overhead. Figure 6 The method 200 in the embodiment of the present application is used as an example to illustrate the specific implementation of the method for updating the timing advance.

[0071] S210, the terminal device determines the time deviation.

[0072] Exemplarily, the terminal device determines the time deviation based on the downlink channel.

[0073] The downlink channel here refers to the physical channel used for downlink transmission of the terminal device, which can also be called the downlink receiving channel, downlink physical channel, etc., and the physical channel refers to the time-frequency resource used to carry high-level (layers above the physical layer) information. The downlink channels involved in this application include but are not limited to the following:

[0074] (1) Physical downlink shared channel (PDSCH) is the main carrier of service data. It can also carry some paging messages, some broadcast messages, uplink and downlink power control messages, etc.

[0075] Data transmission is to put the data to be transmitted on the corresponding time-frequency resources, transmit it through the antenna, and then the receiving end receives the data on the specific time-frequency resources. For downlink and uplink data transmission, the data is carried on the physical downlink shared channel and the physical uplink shared channel respectively.

[0076] (2) Physical downlink control channel (PDCCH), used for the transmission of downlink control information (DCI). Downlink control information DCI includes but is not limited to: scheduling decision information required to receive downlink data from PDSCH and scheduling authorization information that allows terminal devices to transmit uplink data on the physical uplink shared channel (PUSCH).

[0077] The information carried by PDCCH includes the location of time-frequency resources, coding modulation mode, control information of hybrid automatic repeat request (HARQ), etc. The network equipment (i.e., the satellite base station in this application) is the decision maker of uplink and downlink resource scheduling, and controls uplink and downlink data transmission through PDCCH. Specifically, the network equipment controls the format of PDCCH so that PDSCH and PUSCH can transmit multiple types of data.

[0078] (3) Physical broadcast channel (PBCH): used for system broadcast information required for terminal devices to access the network.

[0079] The time deviation in the embodiment of the present application can be understood as the offset of the downlink receiving channel of the terminal device in the time domain, or the time deviation of the uplink timing advance caused by the change of the transmission distance (or transmission delay) between the satellite and the terminal device.

[0080] As an example, the time deviation is the deviation value of the starting position of the first downlink channel in the time domain compared to the starting position of the second downlink channel in the time domain, or, in other words, the time deviation is the deviation value of the starting frame of the first downlink channel in the time domain compared to the starting frame of the second downlink channel, wherein the first downlink channel is the downlink receiving channel of the terminal device at the current moment, the second downlink channel is the downlink receiving channel of the terminal device when the terminal device and the satellite base station complete the uplink and downlink synchronization through the first timing advance, and the first timing advance is the timing advance currently used by the terminal device.

[0081] That is to say, the downlink receiving channel when the terminal device and the satellite base station complete the uplink and downlink synchronization is recorded as the second downlink channel. At this time, the uplink and downlink times are strictly aligned. Therefore, the time domain position of the second downlink channel is offset by the first timing advance amount. The time domain position of the uplink sending channel of the terminal device can be determined. The terminal device performs uplink transmission through the uplink sending channel and can be aligned with the satellite base station side.

[0082] by Figure 3 For example: the TA in the figure corresponds to the first timing advance here, the downlink frame of the terminal device in the figure can be understood as the time domain position of the second downlink channel, and the uplink frame of the terminal device (that is, the time domain position of the uplink transmission channel of the terminal device) is offset from the downlink frame by the first timing advance (that is, TA). The terminal device can achieve uplink and downlink alignment by sending an uplink signal to the satellite base station through the uplink transmission channel. However, after a period of time, due to the high-speed movement of the satellite, the transmission delay between the terminal device and the satellite base station may change, causing the time domain position of the second downlink channel to shift. The current downlink receiving channel of the terminal device is recorded as the first downlink channel, so the time domain position of the first downlink channel will be offset compared to the time domain position of the second downlink channel, and this offset can be understood as the time deviation in this application. Due to the existence of time deviation, the uplink and downlink cannot be aligned, and inter-carrier interference problems may also occur between different terminals.

[0083] by Figure 7 For example ( Figure 7 is Figure 3 Further explanation based on ): TA in the figure corresponds to the first timing advance; assuming that the transmission delay between the terminal device and the satellite base station becomes larger (from delay #1 to delay #2, where delay #1 is 6 time slots and delay #2 is 8 time slots), the starting position of the first downlink channel of the terminal device in the time domain (corresponding to the starting time slot #2 of the terminal device downlink frame in the figure) will be offset backwards compared to the time domain position of the second downlink channel (corresponding to the starting time slot #1 of the terminal device downlink frame in the figure), and the offset is the time deviation. If the position of the uplink frame of the terminal device is still determined according to the first timing advance, the uplink and downlink cannot be aligned.

[0084] In actual application, a synchronization point and a reference point can be set, and the time deviation can be determined according to the deviation between the synchronization point and the reference point. For example, the starting time of the time domain position corresponding to the second downlink channel (i.e., the starting frame of the second downlink channel) is used as the reference point, and the starting time of the time domain position corresponding to the first downlink channel (i.e., the starting frame of the first downlink channel) is used as the synchronization point. The terminal device tracks the change of the time deviation by recording the deviation between the synchronization point and the reference point.

[0085] It can be understood that the above example uses the deviation of the starting positions of the first downlink channel and the second downlink channel in the time domain as an example of time deviation, but the present application is not limited to this implementation method. As long as it is the deviation between the positions of corresponding points of the first downlink channel and the second downlink channel, it can be used as the time deviation. For example, the deviation between the second subframe corresponding to the first downlink channel and the second subframe corresponding to the second downlink channel can also be used as the time deviation.

[0086] In a possible implementation, the terminal device may TA period ) to determine the time deviation. That is, the terminal device TA period Calculate the time deviation once. TA period Can be a preconfigured value.

[0087] S220, the terminal device determines a second timing advance according to the time deviation and the first timing advance.

[0088] Exemplarily, after determining the time deviation, the terminal device determines the second timing advance according to the time deviation and the first timing advance, or updates the first timing advance to the second timing advance. A possible implementation of determining the second timing advance is exemplarily described below.

[0089] In a possible implementation, the terminal device may first determine the uplink and downlink transmission deviations, and then determine the calculation method of the second timing quantity according to the uplink and downlink transmission deviations.

[0090] For example, after determining the time deviation (or at the same time), the terminal device determines the uplink and downlink transmission deviations, and then determines the second timing advance based on the uplink and downlink transmission deviations, the time deviation, and the first timing advance. The uplink and downlink transmission deviations are the time difference between the moment when the terminal device receives the downlink signal through the first downlink channel and the moment when the terminal device sends the uplink signal next time. In other words, the uplink and downlink transmission deviations refer to the time difference between uplink transmission and downlink transmission. If the terminal device performs uplink transmission immediately after receiving the downlink signal, the uplink transmission deviation is 0; if the terminal device waits for a period of time before performing uplink transmission after receiving the downlink signal, the uplink and downlink transmission deviations are the waiting time.

[0091] The reason why the uplink and downlink transmission deviations need to be determined is that the satellite is also in continuous motion during the time interval of uplink and downlink transmissions. If the uplink and downlink transmission deviations are not considered, and only the impact of the time deviation on the timing advance is considered, it may happen that the terminal device updates the timing advance, but after the period corresponding to the uplink and downlink transmission deviations, the updated timing advance is used for uplink transmission, and the uplink and downlink are still not aligned. The reason is that the movement of the satellite during the period corresponding to the uplink and downlink transmission deviations causes the new timing advance to become invalid again. However, if the uplink and downlink transmission deviations are relatively small, their impact can be ignored, and it is not necessary to calculate the impact of the uplink and downlink transmission deviations on the timing advance. The following is a detailed explanation.

[0092] After receiving the downlink signal, the terminal device records the time and records the time as T d The terminal device knows the time of its next uplink transmission, which is recorded as T u It can be understood that the time of the next uplink transmission of the terminal device refers to the time when the uplink signal is first sent after receiving the downlink signal. The terminal device determines the uplink and downlink transmission deviation based on the above two times, which is recorded as T du , where T du =T u -T d .

[0093] In one possible situation (denoted as situation A), when the uplink and downlink transmission deviation is less than or equal to the first threshold, the influence of the uplink and downlink transmission deviation on the timing advance can be ignored. At this time, the second timing advance is determined to be the sum of the first timing advance and the time deviation, that is, the new timing advance (that is, the second timing advance) is obtained by compensating the uplink and downlink deviation (that is, the time deviation) for the original timing advance (that is, the first timing advance), that is, ,in, represents the second timing advance, Indicates the time deviation, Indicates the first timing advance.

[0094] In this implementation, the terminal device can determine the uplink and downlink transmission deviation by itself, and when the uplink and downlink transmission deviation is relatively small (less than or equal to the first threshold), the influence of the uplink and downlink transmission deviation is ignored, and only the value of the time deviation needs to be compensated for the first timing advance to obtain the updated second timing advance. This implementation takes into account the influence of the uplink and downlink transmission deviation on the timing advance, but does not require corresponding compensation for the timing advance as long as there is an uplink and downlink transmission deviation. Instead, when the uplink and downlink transmission deviation is less than the preset first threshold, the influence of the uplink and downlink transmission deviation is ignored, which can reduce the complexity of calculation and reduce resource consumption.

[0095] In a possible implementation, the terminal device TA period Calculate the time deviation once and set it appropriately TA period The value of can not only reduce the calculation frequency of the time deviation and reduce resource consumption, but also avoid the situation where the time deviation is not tracked for a long time, resulting in a large change in the timing advance but not being updated in time, leading to interference between carriers.

[0096] But it is understandable that although the terminal equipment TA period The time offset is calculated once, but it is not necessary to update the first timing advance every time a time offset is calculated. TA period During the period, the transmission delay between the satellite base station and the terminal device changes slightly. At this time, the change in the timing advance may not meet the update requirements. TA period The timing advance may not be updated during a period to reduce resource consumption. TA period During the period, the transmission delay between the satellite base station and the terminal device varies greatly, resulting in the change in the timing advance reaching the update requirement. At this time, the first timing advance needs to be updated to the second timing advance. In the solution provided in the embodiment of the present application, the size of the time deviation can be used to measure whether the timing advance needs to be updated. On the one hand, the time deviation is a value that has been calculated by the terminal device and does not require an additional calculation process. On the other hand, the time deviation can be used to characterize the change in transmission time or the change in timing advance.

[0097] Based on the above analysis, in addition to determining whether the uplink and downlink transmission deviation is less than or equal to the first threshold, the terminal device can also determine whether the time deviation is greater than or equal to the second threshold. Only when the uplink and downlink transmission deviation is less than or equal to the first threshold and the time deviation is greater than or equal to the second threshold, the second timing advance is determined, that is, the second timing advance is determined to be the sum of the first timing advance and the time deviation.

[0098] In another possible situation (represented as situation B), when the uplink and downlink transmission deviation is greater than the first threshold, it is necessary to consider the impact of the uplink and downlink transmission deviation on the timing advance. At this time, the second timing advance is determined to be the sum of the first timing advance, the time deviation and the timing advance deviation. The timing advance deviation is the deviation value of the timing advance of the terminal device caused by the uplink and downlink transmission deviation. That is, the new timing advance (i.e., the second timing advance) is obtained by compensating the original timing advance (i.e., the first timing advance) for the uplink and downlink deviation (i.e., the time deviation) and the deviation of the timing advance caused by the uplink and downlink transmission deviation (i.e., the timing advance deviation). ,in, represents the second timing advance, Indicates the time deviation, represents the timing advance deviation, Indicates the first timing advance.

[0099] In this implementation, the terminal device can determine the uplink and downlink transmission deviation by itself, and when the uplink and downlink transmission deviation is relatively large (greater than the first threshold), the influence of the uplink and downlink transmission deviation on the timing advance is considered, and it is necessary to compensate the value of the time deviation for the first timing advance, and it is also necessary to compensate for the timing advance deviation caused by the uplink and downlink transmission deviation, so as to obtain the updated second timing advance. This implementation considers the influence of the uplink and downlink transmission deviation on the timing advance, and additionally compensates for the timing advance deviation caused by the uplink and downlink transmission deviation when updating the timing advance, so as to improve the accuracy of the calculated timing advance and increase the effective time of the updated timing advance.

[0100] From the above situation A corresponding solution, we can know that the terminal device can TA period The time deviation is calculated once, but it is not necessary to update the first timing advance after each time deviation is calculated. By reducing unnecessary updates to the timing advance, resource consumption can be reduced. However, in case A, it is only necessary to consider whether the time deviation is greater than or equal to the preset second threshold to determine whether the timing advance needs to be updated, because in case A, the time deviation ( ) is the change in timing advance (i.e., the difference between the second timing advance and the first timing advance). However, in case B, both the time deviation and the timing advance deviation need to be considered, because in case B, the time deviation ( ) and timing advance deviation ( ) is the change value of the timing advance.

[0101] Based on the above analysis, in addition to determining whether the uplink and downlink transmission deviation is less than or equal to the first threshold, the terminal device may also determine whether the sum of the time deviation and the timing advance deviation is greater than or equal to the third threshold. Only when the uplink and downlink transmission deviation is greater than the first threshold, and the sum of the time deviation and the timing advance deviation is greater than or equal to the third threshold, the second timing advance is determined, that is, the second timing advance is determined to be the sum of the first timing advance, the time deviation, and the timing advance deviation.

[0102] In summary, the update of the timing advance is triggered only when the change in the timing advance (i.e., the difference between the second timing advance and the first timing advance) is greater than or equal to the third threshold. In this way, the number of updates of the timing advance can be reduced and resource consumption can be reduced. In case A, the change in the timing advance is expressed as the time deviation ( ); In case B, the change in timing advance is expressed by time deviation ( ) and timing advance deviation ( ) and .

[0103] The present application does not limit the specific implementation method of determining the timing advance deviation in situation B. The following is an exemplary description of only one possible implementation method.

[0104] The timing advance deviation is the deviation value of the timing advance of the terminal device caused by the uplink and downlink transmission deviation, or the deviation of the timing advance caused by satellite movement during the time period corresponding to the uplink and downlink transmission deviation. Therefore, it can be considered that the size of the timing advance deviation depends on the size of the uplink transmission deviation and the rate of change of the timing advance. The larger the uplink transmission deviation value and the higher the rate of change of the timing advance, the larger the timing advance deviation. Since the value of the uplink transmission deviation has been determined, how to measure the rate of change of the timing advance is the key to determining the timing advance deviation.

[0105] In a possible implementation, the timing advance deviation is determined according to the third timing advance, the fourth timing advance and the uplink and downlink transmission deviation. The third timing advance is the sum of the time deviation determined by the terminal device in the current calculation cycle and the first timing advance, that is, the current TA periodThe third timing advance is essentially the sum of the time deviation calculated in the calculation cycle and the first timing advance, and the third timing advance is the new timing advance determined in the current calculation cycle considering the influence of the time deviation (equivalent to the second timing advance in the above case A). It can be understood that each calculation cycle is used to calculate the time deviation once, and the time interval between adjacent calculation cycles is the same, which is recorded as TA period .

[0106] The fourth timing advance is the sum of the time deviation determined in the previous calculation cycle and the fifth timing advance. The fifth timing advance is the timing advance used by the terminal device in the previous calculation cycle, that is, the sum of the time deviation calculated in the previous calculation cycle and the fifth timing advance. The essence of the fourth timing advance is the new timing advance determined in the previous calculation cycle considering the influence of the time deviation (for the previous calculation cycle). Therefore, based on the difference between the third timing advance and the fourth timing advance, and the calculation cycle TA period The size of can be used to estimate the rate of change of the timing advance.

[0107] As a possible implementation, this can be achieved by The filtering method is used to determine the timing advance deviation:

[0108] ;

[0109] in, represents the timing advance deviation, represents the third timing advance, represents the fourth timing advance, represents the time interval between adjacent calculation cycles, Indicates the uplink and downlink transmission deviation. is the preconfigured filter coefficient. It can be understood that It is a positive number less than 1 (such as 0.5) and can be determined by testing.

[0110] In the above calculation method, the change rate of the timing advance is estimated through data of two adjacent calculation cycles, and then the change value of the timing advance caused by the uplink and downlink transmission deviation is estimated based on the change rate and the uplink and downlink transmission deviation.

[0111] It is understandable that the timing advance deviation can be calculated in a similar manner for each calculation cycle, and then iterated sequentially. For the Nth calculation cycle, it is the Nth iteration. It can be represented by the following code: “For i=1:N; TA delta-du =(1-α)* TAdelta-du +α*( TA new-i - TA new-i-1 ) / TA period * T du ; End".

[0112] S230, the terminal device performs uplink transmission to the satellite base station according to the second timing advance.

[0113] Exemplarily, after the terminal device updates the first timing advance to the second timing advance, the terminal device performs uplink synchronization through the second timing advance. Specifically, the terminal device performs uplink transmission to the satellite base station based on the second timing advance. The terminal device performs uplink transmission to the satellite base station, which means that the terminal device sends an uplink signal or uplink information to the network device, and the uplink information is carried on the uplink channel.

[0114] It is understandable that the terminal device in the present application has accessed the satellite base station in advance, for example, the terminal device resides in a cell controlled by the satellite base station.

[0115] Optionally, after determining the second timing advance, the terminal device may also report the second timing advance to the satellite base station.

[0116] In the above scheme, the terminal device can update the timing advance by itself, and there is no need for the satellite base station to send TAC to update the timing advance, which can not only improve the updating efficiency of the timing advance, but also reduce the signaling overhead. Specifically, the terminal device uses the starting position of the second downlink channel in the time domain as the reference point, because the second downlink channel is the downlink receiving channel when the terminal device and the satellite base station complete the uplink and downlink synchronization, and the uplink and downlink are aligned at this time. As time goes by, the downlink channel of the terminal device will produce a time deviation. The terminal device can use the starting position of the current first downlink channel in the time domain as a synchronization point and compare it with the above reference point to determine the time deviation. Further, the terminal device can update the current timing advance to the second timing advance based on the first timing advance and the time deviation. In this scheme, the first timing advance is known to the terminal device itself, so the terminal device only needs to determine the time deviation based on the downlink receiving channel, and does not need to obtain other additional information (such as ephemeris information) from the network side to complete the update of the timing advance by itself.

[0117] In the above scheme, the terminal device can sequentially update the timing advance to be used next time based on the timing advance used last time, such as Figure 8As shown in the figure, TA_old in the figure refers to the timing advance used by the terminal device before determining TA0, △TA0, △TA0...△TA N They respectively represent the change of TA, which may be determined by the time deviation, or by the time deviation and the timing advance deviation. It can also be understood that the terminal device does not need to update the timing advance in each calculation cycle, but only updates it when the preset conditions are met. Figure 8 The examples are only given here and do not limit the present application.

[0118] Compared with the solution in which the satellite base station or other network equipment updates the timing advance and notifies the terminal device, the solution in the present application can update the timing advance more conveniently and quickly. Because there will be a certain transmission delay between the terminal device and the satellite base station (or other network device), the satellite base station notifies the terminal device to update the timing advance through downlink signaling, which will not only cause additional signaling overhead but also have relatively low efficiency.

[0119] On the other hand, in the satellite communication scenario, the transmission delay is relatively large. When the terminal device receives the new timing advance sent by the satellite base station, a period of time may have passed, that is, the effective time of the timing advance will be affected.

[0120] On the other hand, a satellite usually serves multiple terminal devices. As the satellite moves at high speed, the timing advance of a large number of terminal devices may need to be frequently updated, which will occupy more resources of the satellite base station. Distributing the task of updating the timing advance to each terminal device can reduce the resource consumption on the satellite base station side. For each terminal device, it only needs to track and update its own timing advance, and the resources consumed are negligible.

[0121] In summary, in the above scheme provided in the embodiment of the present application, the terminal device can use its own known information to complete the update of the timing advance by itself, which can improve the updating efficiency of the timing advance, reduce the signaling overhead between the terminal device and the satellite base station, and also increase the effective time of the timing advance, as well as reduce resource consumption on the network side.

[0122] It should be noted that, in addition to achieving the above-mentioned beneficial effects, the solution provided by the embodiment of the present application can also ensure a higher accuracy of the timing advance. Fig. 9 and Fig.10 is a simulation result corresponding to the solution of this application. Fig. 9 Schematic diagram of the deviation between the value of the timing advance calculated by the solution of the present application and the value of the actual timing advance. Fig. 9 It can be seen that the error value is controlled below 0.06 microseconds, which can fully meet practical applications. Fig.10 The error percentage between the timing advance value calculated by the present application solution and the actual timing advance value. It can be seen from the figure that the maximum error percentage does not exceed 1.2%. If the abnormal data is removed, the error percentage is below 0.2%, which can meet the actual application.

[0123] Corresponding to the solution provided in the above embodiment, the embodiment of the present application also provides a schematic diagram of functional components of a terminal device, such as Fig.11 The method for updating the timing advance provided in the embodiment of the present application can be applied to the following examples: Fig.11 In the terminal device 300 shown.

[0124] like Fig.11 As shown, the terminal device 300 may include a processor 301, a display screen 303, a communication module 302, etc.

[0125] The processor 301 may include one or more processing units, for example, the processor 301 may include an application processor (AP), a modem processor, a graphics processor (GPU), an image signal processor (ISP), a controller, a memory, a video stream codec, a digital signal processor (DSP), a baseband processor, and / or a neural-network processing unit (NPU), etc. Different processing units may be independent devices or integrated into one or more processors 301.

[0126] In some embodiments, the processor 301 may include one or more interfaces. The interface may include an inter-integrated circuit (I2C) interface, an inter-integrated circuits sound (I2S) interface, a pulse code modulation (PCM) interface, a universal asynchronous receiver / transmitter (UART) interface, a mobile industry processor interface (MIPI), a general-purpose input / output (GPIO) interface, a subscriber identity module (SIM) interface, and / or a universal serial bus (USB) interface, etc.

[0127] Corresponding to the embodiment of the present application, the processor 301 can execute the solution executed by the terminal device in the embodiment of the present application by calling the executable code in the memory (not shown in the figure).

[0128] The terminal device 300 implements the display function through the GPU, the display screen 303, and the application processor, etc. The display screen 303 is used to display images, video streams, etc.

[0129] The communication module 302 enables the terminal device to have a wireless communication function. Corresponding to the embodiment of the present application, the terminal device can communicate with the satellite base station through the communication module 302.

[0130] The communication module 302 may include an antenna x, an antenna y, a mobile communication module 302A, and / or a wireless communication module 302B. For example, the communication module 302 includes the antenna x, the antenna y, the mobile communication module 302A, and the wireless communication module 302B.

[0131] The wireless communication function of the terminal device 300 can be implemented through antenna x, antenna y, mobile communication module 302A, wireless communication module 302B, modem processor and baseband processor.

[0132] Antenna x and antenna y are used to transmit and receive electromagnetic wave signals. Each antenna in the terminal device 300 can be used to cover a single or multiple communication frequency bands. Different antennas can also be reused to improve the utilization of the antennas. For example, antenna x can be reused as a diversity antenna for a wireless local area network. In some other embodiments, the antenna can be used in combination with a tuning switch.

[0133] The mobile communication module 302A can provide solutions for wireless communications including 2G / 3G / 4G / 5G, etc., applied to the terminal device 300. The mobile communication module 302A may include at least one filter, a switch, a power amplifier, a low noise amplifier (LNA), etc. The mobile communication module 302A may receive electromagnetic waves through the antenna x, and filter, amplify, and process the received electromagnetic waves, and transmit them to the modulation and demodulation processor for demodulation. The mobile communication module 302A may also amplify the signal modulated by the modulation and demodulation processor, and convert it into electromagnetic waves for radiation through the antenna x. In some embodiments, at least some of the functional modules of the mobile communication module 302A may be arranged in the processor 301. In some embodiments, at least some of the functional modules of the mobile communication module 302A may be arranged in the same device as at least some of the modules of the processor 301.

[0134] The wireless communication module 302B can provide wireless communication solutions including wireless local area networks (WLAN) (such as wireless fidelity (Wi-Fi) networks), bluetooth (BT), global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), infrared (IR), etc., which are applied to the terminal device 300. The wireless communication module 302B can be one or more devices integrating at least one communication processing module. The wireless communication module 302B receives electromagnetic waves via antenna y, modulates the frequency of the electromagnetic wave signal and performs filtering processing, and sends the processed signal to the processor 301. The wireless communication module 302B can also receive the signal to be sent from the processor 301, modulate the frequency of the signal, amplify it, and convert it into electromagnetic waves for radiation through the antenna y.

[0135] In some embodiments, the antenna x of the terminal device 300 is coupled to the mobile communication module 302A, and the antenna y is coupled to the wireless communication module 302B, so that the terminal device 300 can communicate with the network and other devices through wireless communication technology. The wireless communication technology may include global system for mobile communications (GSM), general packet radio service (GPRS), code division multiple access (CDMA), wideband code division multiple access (WCDMA), time-division code division multiple access (TD-SCDMA), long term evolution (LTE), BT, GNSS, WLAN, NFC, FM, and / or IR technology, etc. The GNSS may include a global positioning system (GPS), a global navigation satellite system (GLONASS), a Beidou navigation satellite system (BDS), a quasi-zenith satellite system (QZSS) and / or a satellite based augmentation system (SBAS).

[0136] In some possible embodiments, the above wireless communication technology may also include a satellite mobile communication system, such as the Tiantong satellite mobile communication system and the Iridium satellite mobile communication system. Fig.11 The antenna x and / or antenna y in the embodiment may be a linear polarization antenna in the embodiment of the present application. For example, the antenna y is coupled with the wireless communication module 302B, and realizes the satellite communication function by communicating with the above-mentioned satellite mobile communication system.

[0137] It should be understood that the structure illustrated in this embodiment does not constitute a specific limitation on the terminal device 300. In other embodiments, the terminal device 300 may include more or fewer components than shown in the figure, or combine some components, or split some components, or arrange the components differently. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0138] Fig.12 FIG. 4 is a schematic diagram showing a simplified structure of another terminal device 400 provided in an embodiment of the present application. For ease of understanding and illustration, Fig.12 In the example, a mobile phone is used as the terminal device. Fig.12 As shown, the terminal device includes a processor, a memory, a radio frequency circuit, an antenna, and an input-output device. The processor is mainly used to process communication protocols and communication data, as well as to control the terminal, execute software programs, process software program data, etc. The memory is mainly used to store software programs and data. The radio frequency circuit is mainly used for conversion between baseband signals and radio frequency signals and processing of radio frequency signals. The antenna is mainly used to send and receive radio frequency signals in the form of electromagnetic waves. Input-output devices, such as touch screens, display screens, keyboards, etc., are mainly used to receive data input by users and output data to users. It should be noted that some types of terminal devices may not have input-output devices.

[0139] When data needs to be sent, the processor performs baseband processing on the data to be sent and outputs the baseband signal to the RF circuit. The RF circuit performs RF processing on the baseband signal and then sends the RF signal outward in the form of electromagnetic waves through the antenna. When data is sent to the terminal, the RF circuit receives the RF signal through the antenna, converts the RF signal into a baseband signal, and outputs the baseband signal to the processor. The processor converts the baseband signal into data and processes the data. For ease of explanation, Fig.12 Only one memory and processor are shown. In an actual terminal product, there may be one or more processors and one or more memories. The memory may also be referred to as a storage medium or a storage device. The memory may be set independently of the processor or may be integrated with the processor, which is not limited in the embodiments of the present application.

[0140] In the embodiments of the present application, the antenna and the radio frequency circuit having transceiver functions may be regarded as the transceiver unit of the terminal, and the processor having the processing function may be regarded as the processing unit of the terminal. Fig.12 As shown, the terminal device includes a transceiver unit 410 and a processing unit 420. The transceiver unit may also be referred to as a transceiver, a transceiver, a transceiver device, etc. The processing unit may also be referred to as a processor, a processing board, a processing module, a processing device, etc. Optionally, the device used to implement the receiving function in the transceiver unit 410 may be regarded as a receiving unit, and the device used to implement the sending function in the transceiver unit 410 may be regarded as a sending unit, that is, the transceiver unit 410 includes a receiving unit and a sending unit. The transceiver unit may sometimes be referred to as a transceiver, a transceiver, or a transceiver circuit, etc. The receiving unit may sometimes be referred to as a receiver, a receiver, or a receiving circuit, etc. The sending unit may sometimes be referred to as a transmitter, a transmitter, or a transmitting circuit, etc.

[0141] It should be understood that the transceiver unit 410 is used to perform sending operations and receiving operations on the terminal side in the above method embodiment, and the processing unit 420 is used to perform other operations on the terminal except the sending and receiving operations in the above method embodiment.

[0142] For example, in one implementation, the processing unit 420 is used to execute Figure 6 The transceiver unit 410 is used to perform transceiver operations, and / or the transceiver unit 410 is also used to perform other transceiver steps on the terminal side in the embodiment of the present application.

[0143] When the device is a chip, the chip includes a transceiver unit and a processing unit, wherein the transceiver unit may be an input / output circuit or a communication interface; and the processing unit may be a processor or a microprocessor or an integrated circuit integrated on the chip.

[0144] Understandably, Fig.11 and Fig.12 The device corresponding to the method embodiment provided in the present application includes a module for executing the corresponding each of the above method embodiments. The module can be software, hardware, or a combination of software and hardware. It can be understood that the technical features described in the above method embodiments are also applicable to the device embodiment. Therefore, the content not described in detail can be referred to the above method embodiment, and for the sake of brevity, it will not be repeated here.

[0145] An embodiment of the present application also provides a computer-readable storage medium on which computer instructions for implementing the method executed by the first network device in the above method embodiment are stored.

[0146] For example, when the computer program is executed by a computer, the computer can implement the method performed by the network device in the above method embodiment.

[0147] An embodiment of the present application also provides a computer program product comprising instructions, which, when executed by a computer, enables the computer to implement the method executed by the first device in the above method embodiment, or the method executed by the second device.

[0148] An embodiment of the present application also provides a communication system, which includes the network device in the above embodiment.

[0149] The explanation of the relevant contents and beneficial effects of any of the above-mentioned devices can be referred to the corresponding method embodiments provided above, which will not be repeated here.

[0150] In an embodiment of the present application, the network device may include a hardware layer, an operating system layer running on the hardware layer, and an application layer running on the operating system layer. Among them, the hardware layer may include hardware such as a central processing unit (CPU), a memory management unit (MMU), and a memory (also called main memory). The operating system of the operating system layer may be any one or more computer operating systems that implement business processing through processes, such as Linux operating system, Unix operating system, Android operating system, iOS operating system, or Windows operating system. The application layer may include applications such as browsers, address books, word processing software, and instant messaging software.

[0151] The embodiments of the present application do not specifically limit the specific structure of the execution subject of the method provided in the embodiments of the present application, as long as it is possible to communicate according to the method provided in the embodiments of the present application by running a program that records the code of the method provided in the embodiments of the present application. For example, the execution subject of the method provided in the embodiments of the present application may be a network device, or a functional module in the network device that can call and execute a program.

[0152] Various aspects or features of the present application may be implemented as a method, apparatus, or article of manufacture using standard programming and / or engineering techniques. The term "article of manufacture" as used herein may encompass a computer program accessible from any computer-readable device, carrier, or medium. For example, a computer-readable medium may include, but is not limited to, a magnetic storage device (e.g., a hard disk, a floppy disk, or a magnetic tape, etc.), an optical disk (e.g., a compact disc (CD), a digital versatile disc (DVD), etc.), a smart card, and a flash memory device (e.g., an erasable programmable read-only memory (EPROM), a card, a stick, or a key drive, etc.).

[0153] The various storage media described herein may represent one or more devices and / or other machine-readable media for storing information. The term "machine-readable medium" may include, but is not limited to, wireless channels and various other media capable of storing, containing and / or carrying instructions and / or data.

[0154] It should be understood that the processor mentioned in the embodiments of the present application may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0155] It should also be understood that the memory mentioned in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM). For example, RAM can be used as an external cache. By way of example and not limitation, RAM may include the following forms: static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0156] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, the memory (storage module) can be integrated into the processor.

[0157] It should also be noted that the memory described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0158] Those of ordinary skill in the art will appreciate that the units and steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of protection of this application.

[0159] Those skilled in the art can clearly understand that, for the sake of convenience and brevity of description, the specific working processes of the above-described devices and units can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0160] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0161] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to implement the solution provided by the present application.

[0162] In addition, each functional unit in each embodiment of the present application may be integrated into one unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0163] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. For example, the computer may be a personal computer, a server, or a network device, etc. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from one website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state disk (SSD)). For example, the aforementioned available medium may include, but is not limited to, various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0164] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims and the specification.

Claims

1. A method for updating a timing advance, characterized in that: include: The terminal device determines a time deviation and an uplink and downlink transmission deviation, wherein the time deviation is a deviation value of a starting position of a first downlink channel in the time domain compared to a starting position of a second downlink channel in the time domain, the first downlink channel is a downlink receiving channel of the terminal device at the current moment, the second downlink channel is a downlink receiving channel of the terminal device when the terminal device completes uplink and downlink synchronization with a satellite base station through a first timing advance, the first timing advance is a timing advance currently used by the terminal device, and the uplink and downlink transmission deviation is a time difference between a moment when the terminal device receives a downlink signal through the first downlink channel and a moment when the terminal device sends an uplink signal next time; The terminal device determines a second timing advance according to the uplink and downlink transmission deviation, the time deviation and the first timing advance; The terminal device performs uplink transmission to the satellite base station according to the second timing advance.

2. The method according to claim 1, characterized in that The terminal device determines the second timing advance according to the uplink and downlink transmission deviation, the time deviation, and the first timing advance, including: When the uplink and downlink transmission deviation is less than or equal to a first threshold, the second timing advance is determined to be the sum of the first timing advance and the time deviation.

3. The method according to claim 2, characterized in that The step of determining, when the uplink and downlink transmission deviation is less than or equal to a first threshold, that the second timing advance is a sum of the first timing advance and the time deviation, includes: When the uplink and downlink transmission deviation is less than or equal to a first threshold and the time deviation is greater than or equal to a second threshold, the second timing advance is determined to be the sum of the first timing advance and the time deviation.

4. The method according to claim 1, characterized in that: The terminal device determines the second timing advance according to the uplink and downlink transmission deviation, the time deviation, and the first timing advance, including: When the uplink and downlink transmission deviation is greater than a first threshold, the second timing advance is determined to be the sum of the first timing advance, the time deviation and the timing advance deviation, and the timing advance deviation is the deviation value of the timing advance of the terminal device caused by the uplink and downlink transmission deviation.

5. The method according to claim 4, characterized in that The step of determining, when the uplink and downlink transmission deviation is greater than a first threshold, that the second timing advance is a sum of the first timing advance, the time deviation, and the timing advance deviation, includes: When the uplink and downlink transmission deviation is greater than the first threshold, and the sum of the time deviation and the timing advance deviation is greater than or equal to a third threshold, the second timing advance is determined to be the sum of the first timing advance, the time deviation and the timing advance deviation.

6. The method according to claim 4 or 5, characterized in that: The method further comprises: The timing advance deviation is determined according to a third timing advance and a fourth timing advance, the third timing advance being the sum of the time deviation determined by the terminal device in a current calculation cycle and the first timing advance, the fourth timing advance being the sum of the time deviation determined in a previous calculation cycle and a fifth timing advance, the fifth timing advance being the timing advance used by the terminal device in the previous calculation cycle, each calculation cycle being used to calculate the time deviation once, and the time intervals of adjacent calculation cycles are the same.

7. The method according to claim 6, characterized in that The third timing advance, the fourth timing advance, and the timing advance deviation satisfy the following relationship: ； in, represents the timing advance deviation, represents the third timing advance, represents the fourth timing advance, represents the time interval between adjacent calculation cycles, represents the uplink and downlink transmission deviation, are preconfigured filter coefficients.

8. The method according to any one of claims 1 to 5, characterized in that Before the terminal device performs uplink transmission to the satellite base station according to the second timing advance, the method further includes: The terminal device reports the second timing advance to the satellite base station.

9. A terminal device, characterized in that: The terminal device includes: one or more processors, and a memory; The memory is coupled to the one or more processors, and the memory is used to store computer program codes, wherein the computer program codes include computer instructions, and the one or more processors call the computer instructions to enable the terminal device to execute the method according to any one of claims 1 to 8.

10. A chip system, characterized in that: The chip system is applied to a terminal device, and the chip system includes one or more processors, and the one or more processors are used to call computer instructions so that the terminal device executes the method as described in any one of claims 1 to 8.

11. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes instructions, and when the instructions are executed on a terminal device, the terminal device executes the method according to any one of claims 1 to 8.

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