Method and apparatus for determining timing advance (TA)

Abstract

The present application provides a method and apparatus for determining a timing advance (TA). The method can be applied to the field of communications. The method comprises: receiving a cell handover command sent by a serving cell; determining whether the cell handover command comprises a first TA; if the cell handover command comprises the first TA, using the first TA to communicate with a target cell; and if the cell handover command does not comprise the first TA, using a second TA or a third TA to communicate with the target cell, the second TA being a TA determined by a terminal device on the basis of reference signals of the serving cell and the target cell, and the third TA being a TA determined by the terminal device when initiating a random access procedure to the target cell after receiving the cell handover command. By means of the method, when multiple TA acquisition modes coexist, a terminal device can correctly determine a TA for communicating with a target cell, thereby ensuring the quality and stability of communications of the terminal device.

Description

Method and device for determining timing advance TA

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on August 11, 2023, with application number 202311018822.8 and application name “Method and Device for Determining Timing Advance TA”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communications, and more particularly, to a method and apparatus for determining a timing advance (TA). Background Art

[0003] In mobile communication systems, terminal devices and base stations need to maintain synchronization to achieve normal communication. This synchronization is achieved by measuring a reference signal that can be used for timing synchronization. The base station sends this reference signal to the mobile device, and the mobile device then performs timing transmission based on this reference signal. Because it takes a certain amount of time for the signal to propagate through space, and the mobile device may be located at the edge of the base station's coverage, signal transmission delays occur. To compensate for this delay and maintain synchronization, the mobile device needs to send the signal before the predetermined time. This advance time is called timing advance (TA). With timing advance, the terminal device can communicate with the base station at the correct time.

[0004] However, currently during the cell handover process, the terminal device needs to determine the TA for communicating with the target cell to ensure the quality and stability of communication.

[0005] Summary of the Invention

[0006] The present application provides a method and apparatus for determining a timing advance TA, which can correctly determine the TA for communicating with a target cell when multiple methods for obtaining the TA coexist, thereby ensuring the quality and stability of communication of a terminal device.

[0007] In the first aspect, a method for determining a timing advance TA is provided, the method comprising: receiving a cell switching command sent by a serving cell; determining whether a first TA is included in the cell switching command; if the first TA is included in the cell switching command, using the first TA to communicate with the target cell; if the first TA is not included in the cell switching command, using a second TA or a third TA to communicate with the target cell, the second TA being a TA determined by a terminal device based on reference signals of the serving cell and the target cell, and the third TA being a TA determined by the terminal device when initiating a random access process to the target cell after receiving the cell switching command.

[0008] Among them, the service cell may refer to the cell to which the terminal device is currently connected. By establishing a connection with the service cell, the terminal device can perform communication activities such as data transmission and voice calls; the target cell may refer to the cell that is connected and communicated with the terminal device after cell switching.

[0009] Optionally, the first TA included in the cell switching command may refer to a TA value, or may indicate TA=0, or may be used to indicate that the TA value is equal to the current serving cell.

[0010] Optionally, the second TA may be determined based on a time difference between arrival of downlink reference signals of the serving cell and the target cell.

[0011] Optionally, the random access procedure may include a contention-based random access procedure or a contention-free random access procedure.

[0012] In an embodiment of the present application, after receiving a cell switching command, the terminal device can determine the TA (first TA, second TA or third TA) for communicating with the target cell by judging whether the cell switching command includes the first TA. In this way, the terminal device can correctly determine the TA for communicating with the target cell when multiple methods of obtaining the TA coexist, thereby ensuring the quality and stability of the terminal device's communication.

[0013] In combination with the first aspect, in certain implementations of the first aspect, before using the first TA to communicate with the target cell, the method also includes: determining that a first timer has not timed out, and the first timer is a timer that starts timing after the terminal device sends a random access request to the target cell.

[0014] Optionally, the first timer may be configured by the network device to the terminal device.

[0015] In an embodiment of the present application, the first TA is included in the cell switching command, and when the first timer has not timed out, the terminal device uses the first TA to communicate with the target cell. In this way, when the first TA is included in the cell switching command, the validity of the first TA can be further verified, thereby helping the terminal device to correctly select the TA to communicate with the target cell.

[0016] In combination with the first aspect, in certain implementations of the first aspect, the second TA is obtained by the terminal device measuring the synchronization signal block SSB of the serving cell and the target cell at the first moment, and the use of the second TA or the third TA to communicate with the target cell includes: if the second timer has not timed out, using the second TA to communicate with the target cell, and the second timer is a timer starting from the first moment.

[0017] Optionally, the terminal device can determine the second TA by measuring the time difference between the SSB arrival downlink of the serving cell and the target cell.

[0018] Optionally, when the second timer expires, the terminal device may re-measure the SSBs of the serving cell and the target cell at a second moment, where the second moment is greater than the first moment, and before the second moment, the second TA obtained by the terminal device is temporarily invalid.

[0019] In an embodiment of the present application, when the cell switching command does not include the first TA and the second timer is valid, the terminal device can use the second TA to communicate with the target cell. In this way, when the first TA is not included in the cell switching command, the validity of the second TA can be further verified, thereby helping the terminal device to correctly select the TA to communicate with the target cell, thereby ensuring stable and high-quality communication between the terminal device and the target cell.

[0020] In combination with the first aspect, in certain implementations of the first aspect, the using the second TA or the third TA to communicate with the target cell includes: if the second timer times out, using the third TA to communicate with the target cell.

[0021] In an embodiment of the present application, if the cell handover command does not include the first TA and the second timer expires, the terminal device can use the third TA to communicate with the target cell. In this way, it is possible to avoid the terminal device mistakenly selecting the TA for communication with the target cell, thereby preventing the loss of transmitted data.

[0022] In combination with the first aspect, in certain implementations of the first aspect, the use of the second TA or the third TA to communicate with the target cell includes: if the random access process is a contention-free random access process, using the third TA to communicate with the target cell.

[0023] In an embodiment of the present application, when the cell switching command does not include the first TA, and the third TA is the TA for the terminal device to initiate contention-free random access resource acquisition, the terminal device can use the third TA to communicate with the target cell. In this way, when multiple methods of obtaining TA coexist, the terminal device can correctly select the TA to be used, so that the terminal device can maintain efficient communication with the target cell in a changing communication environment.

[0024] In combination with the first aspect, in certain implementations of the first aspect, before receiving the cell switching command sent by the serving cell, the method further includes: sending capability information to the serving cell, wherein the capability information is used to indicate the number of TAs that the terminal device can obtain or maintain from the target cell.

[0025] In an embodiment of the present application, before receiving a switching command sent by a serving cell, the terminal device may report capability information to the serving cell. The capability information is associated with the subsequent TA selection behavior of the terminal device, so as to facilitate the terminal device to select a qualified TA to ensure the quality and stability of the terminal device's communication.

[0026] On the second aspect, a method for determining a timing advance TA is provided, the method comprising: receiving a cell switching command sent by a serving cell, the cell switching command including a first TA; obtaining a third TA, the third TA being the TA determined by the terminal device when initiating a contention-free random access process to the target cell after receiving the cell switching command; and communicating with the target cell according to the third TA.

[0027] Alternatively, when the cell switching command does not include the first TA, the terminal device may also communicate with the target cell according to the third TA.

[0028] In an embodiment of the present application, even if the cell switching command includes a first TA, the terminal device can also communicate with the target cell using a third TA determined by a contention-free random access process. In this way, the terminal device can correctly determine the TA for communicating with the target cell when multiple methods of obtaining the TA coexist, thereby ensuring the quality and stability of the terminal device's communication.

[0029] In combination with the second aspect, in certain implementations of the second aspect, before communicating with the target cell according to the third TA, the method further includes: determining that a first timer has expired, where the first timer is a timer that starts timing after sending a random access request to the target cell.

[0030] In an embodiment of the present application, the first TA is included in the cell switching command, and when the first timer expires, the terminal device can use the third TA to communicate with the target cell. In this way, it is possible to avoid using the invalid first TA to communicate with the target cell, thereby causing the loss of transmitted data.

[0031] In combination with the second aspect, in certain implementations of the second aspect, before receiving the cell switching command sent by the serving cell, the method further includes: sending capability information to the serving cell, wherein the capability information is used to indicate the number of TAs that the terminal device can obtain or maintain from the target cell.

[0032] In an embodiment of the present application, before receiving a switching command sent by a serving cell, the terminal device may report capability information to the serving cell. The capability information is associated with the subsequent TA selection behavior of the terminal device, facilitating the terminal device to select a qualified TA to ensure the quality and stability of communication.

[0033] According to a third aspect, a method for obtaining a timing advance TA is provided, the method comprising: obtaining a second TA and a third TA, wherein the second TA is a TA determined by the terminal device based on reference signals of the serving cell and the target cell, and the third TA is a TA determined by the terminal device when initiating a random access process to the target cell after receiving the cell switching command; and determining a target TA for communicating with the target cell according to preset rules.

[0034] Optionally, the above-mentioned preset rules may define the priorities of the second TA and the third TA. When the priority of the defined second TA is higher than the priority of the third TA, the above-mentioned target TA may be the second TA. When the priority of the defined third TA is higher than the second TA, the above-mentioned target TA may be the third TA.

[0035] Optionally, when the third TA is a TA acquired through a contention-free random access process, the above preset rule or defined priority may be: giving priority to using the third TA, that is, the target TA is the third TA.

[0036] Optionally, when the third TA is a TA acquired through a contention-based random access process, the preset rule or defined priority may be: preferentially using the second TA, that is, the target TA is the second TA.

[0037] In the embodiment of the present application, when the TA obtained autonomously by the terminal device and the TA obtained through the random access process coexist, the TA for communicating with the target cell can be determined according to a preset rule. In this way, the terminal device can correctly determine the TA for communicating with the target cell when multiple TA acquisition methods coexist, thereby ensuring the quality and stability of the terminal device's communication.

[0038] In a fourth aspect, a device for determining a timing advance TA is provided, the device comprising: a transceiver unit for receiving a cell switching command sent by a serving cell; a processing unit for determining whether the cell switching command includes a first TA; if the cell switching command includes the first TA, using the first TA to communicate with the target cell; if the cell switching command does not include the first TA, using a second TA or a third TA to communicate with the target cell, the second TA being a TA determined by the terminal device based on the reference signals of the serving cell and the target cell, and the third TA being a TA determined by the terminal device when initiating a random access process to the target cell after receiving the cell switching command.

[0039] In combination with the fourth aspect, in certain implementations of the fourth aspect, the processing unit is further used to determine that a first timer has not timed out, and the first timer is a timer that starts timing after the terminal device sends a random access request to the target cell.

[0040] In combination with the fourth aspect, in certain implementations of the fourth aspect, the second TA is obtained by the terminal device measuring the synchronization signal block SSB of the serving cell and the target cell at the first moment; the processing unit is specifically used to use the second TA to communicate with the target cell if the second timer has not timed out, and the second timer is a timer that starts counting from the first moment.

[0041] In combination with the fourth aspect, in certain implementations of the fourth aspect, the processing unit is specifically configured to use the third TA to communicate with the target cell if the second timer times out.

[0042] In combination with the fourth aspect, in certain implementations of the fourth aspect, the processing unit is specifically configured to use the third TA to communicate with the target cell if the random access procedure is a contention-free random access procedure.

[0043] In combination with the fourth aspect, in certain implementations of the fourth aspect, the transceiver unit is further used to send capability information to the serving cell, where the capability information is used to indicate the number of TAs that the terminal device can obtain or maintain from the target cell.

[0044] In the fifth aspect, a device for determining a timing advance TA is provided, the device comprising: a transceiver unit for receiving a cell switching command sent by a serving cell, the cell switching command including a first TA; a processing unit for: obtaining a third TA, the third TA being the TA determined by the terminal device when initiating a contention-free random access process to the target cell after receiving the cell switching command; and communicating with the target cell according to the third TA.

[0045] In combination with the fifth aspect, in certain implementations of the fifth aspect, the processing unit is further used to determine that a first timer has expired, where the first timer is a timer that starts timing after sending a random access request to the target cell.

[0046] In combination with the fifth aspect, in certain implementations of the fifth aspect, the transceiver unit is further used to send capability information to the serving cell, where the capability information is used to indicate the number of TAs that the terminal device can obtain or maintain from the target cell.

[0047] In combination with the fifth aspect, in certain implementations of the fifth aspect, the device includes: at least one processor and a memory, the at least one processor being coupled to the memory and configured to read and execute instructions in the memory, so that the device implements the method in any one of the implementations of the first or second aspect above.

[0048] In the sixth aspect, a device for determining a timing advance TA is provided, the device comprising: a processing unit, used to: obtain a second TA and a third TA, the second TA being a TA determined by the terminal device based on the reference signals of the serving cell and the target cell, and the third TA being a TA determined by the terminal device when initiating a random access process to the target cell after receiving the cell switching command; determining a target TA for communicating with the target cell according to preset rules.

[0049] In the seventh aspect, a device for determining a timing advance TA is provided, the device comprising a processor, the processor being used to couple with a memory, read and execute instructions and / or program codes in the memory to execute a method of any one of the implementation methods of the first to third aspects.

[0050] In an eighth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a program code. When the computer program code is run on a computer, the computer executes the method in any one of the implementation methods of the first to third aspects above.

[0051] In a ninth aspect, a chip is provided, which includes a circuit for executing the method in any one of the implementations of the first to third aspects above.

[0052] In a tenth aspect, a computer program product is provided, which includes a computer program. When the computer program is run, the computer executes the method in any one of the implementation modes of the first to third aspects above.

[0053] In the eleventh aspect, a terminal device is provided, comprising: an apparatus according to any one of the implementation methods of the fourth to sixth aspects above. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] FIG1 is a schematic diagram of a method for a terminal device to obtain uplink timing synchronization of an unconnected cell provided in an embodiment of the present application;

[0055] FIG2 is a schematic diagram of a terminal device obtaining a TA in various ways according to an embodiment of the present application;

[0056] FIG3 is a diagram of a system architecture applicable to the method for determining the timing advance TA provided in an embodiment of the present application;

[0057] FIG4 is a schematic diagram of an application scenario of a method for determining a timing advance TA provided in an embodiment of the present application;

[0058] FIG5 is a schematic flowchart of a method for determining a timing advance TA provided in an embodiment of the present application;

[0059] FIG6 is a schematic flowchart of a method for determining a timing advance TA provided in an embodiment of the present application;

[0060] FIG7 is a schematic flowchart of another method for determining a timing advance TA provided in an embodiment of the present application;

[0061] FIG8 is a schematic diagram of a device for determining a timing advance TA provided in an embodiment of the present application;

[0062] FIG9 is a schematic diagram of another device for determining a timing advance TA provided in an embodiment of the present application. DETAILED DESCRIPTION

[0063] The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

[0064] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: global system of mobile communication (GSM) system, code division multiple access (CDMA) system, wideband code division multiple access (WCDMA) system, general packet radio service (GPRS), long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), universal mobile telecommunication system (UMTS), worldwide interoperability for microwave access (WiMAX) communication system, future fifth generation (5G) system or new radio (NR), etc.

[0065] The terminal device in the embodiments of the present application may refer to a user device, an access terminal, a user unit, a user station, a mobile station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent, or a user apparatus. The terminal device may also be a cellular phone, 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 capabilities, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a wearable device, a terminal device in a future 5G network, or a terminal device in a future evolved public land mobile network (PLMN), etc., and the embodiments of the present application are not limited thereto.

[0066] The network device in the embodiment of the present application can be a device for communicating with a terminal device. The network device can be a base station (base transceiver station, BTS) in a global system of mobile communication (GSM) system or code division multiple access (CDMA), or a base station (NodeB, NB) in a wideband code division multiple access (WCDMA) system, or an evolved base station (eNB or eNodeB) in an LTE system, or a wireless controller in a cloud radio access network (CRAN) scenario, or the network device can be a relay station, an access point, a vehicle-mounted device, a wearable device, a network device in a future 5G network, or a network device in a future evolved PLMN network, etc., and the embodiment of the present application is not limited.

[0067] To facilitate understanding of the embodiments of the present application, first, a brief introduction to the concepts and technologies involved in the embodiments of the application is given.

[0068] (1) Beam: A beam is a communication resource. A beam can be a wide beam, a narrow beam, or other types of beams. The technology for forming the beam can be beamforming technology or other technical means. Beamforming technology can specifically be digital beamforming technology, analog beamforming technology, and hybrid digital / analog beamforming technology. Different beams can be considered as different resources. The same information or different information can be sent through different beams. Optionally, multiple beams with the same or similar communication characteristics can be considered as one beam. A beam can include one or more antenna ports for transmitting data channels, control channels, and detection signals. For example, a transmit beam can refer to the distribution of signal strength in different directions in space after a signal is transmitted by an antenna, and a receive beam can refer to the distribution of signal strength in different directions in space of a wireless signal received from an antenna. It can be understood that one or more antenna ports forming a beam can also be considered as an antenna port set.

[0069] When using low-frequency or medium-frequency bands, signals can be sent omnidirectionally or through a wider angle. When using high-frequency bands, thanks to the smaller carrier wavelength of high-frequency communication systems, antenna arrays consisting of many antenna elements can be arranged at the transmitting and receiving ends. The transmitting end sends signals with certain beamforming weights, so that the transmitted signals form a beam with spatial directionality. At the same time, the receiving end uses an antenna array with certain beamforming weights to receive the signals, which can improve the received signal power at the receiving end and combat path loss.

[0070] (2) Reference signal: According to the Long Term Evolution (LTE) / NR protocol, at the physical layer, uplink communication includes the transmission of uplink physical channels and uplink signals. Uplink physical channels include random access channels (PRACH), PUCCH, and PUSCH, and uplink signals include channel sounding signals (SRS), uplink control channel demodulation reference signals (PUCCH de-modulation reference signals, PUCCH-DMRS), uplink data channel demodulation reference signals (PUSCH-DMRS), uplink phase noise tracking reference signals (PTRS), uplink positioning signals (uplink positioning RS), etc. Downlink communication includes the transmission of downlink physical channels and downlink signals. The downlink physical channels include the physical broadcast channel (PBCH), the physical downlink control channel (PDCCH), the PDSCH, etc. The downlink signals include the primary synchronization signal (PSS) / secondary synchronization signal (SSS), the downlink control channel demodulation reference signal PDCCH-DMRS, the downlink data channel demodulation reference signal PDSCH-DMRS, the phase noise tracking signal PTRS, the channel status information reference signal (CSI-RS), the cell reference signal (CRS) (not available in NR), the time / frequency tracking reference signal (TRS) (not available in LTE), the LTE / NR positioning signal (positioning RS), etc.

[0071] (3) Cell Switch Command (CSC): The 3rd Generation Partnership Project (3GPP) standard defines a new handover command in Rel-18 mobility topic, which is sent based on MAC CE signaling. This signaling can carry information such as the target cell (cell group) identifier (which may be a configuration logical identifier rather than a cell identifier), beam indication information (such as TCI state identifier), TA value, and uplink and / or downlink bandwidth part (BWP) identifier.

[0072] The technical problems and technical solutions to be solved by this application are explained below with reference to the accompanying drawings.

[0073] In mobile communication systems, terminal devices and base stations must maintain synchronization to ensure normal communication. This synchronization is achieved by measuring a reference signal that can be used for timing synchronization. The base station sends this reference signal to the mobile device, which then uses it to time its transmissions. Since signals take time to propagate through space, and mobile devices may be located at the edge of a base station's coverage, signal transmission delays occur. To compensate for this delay and maintain synchronization, mobile devices need to send signals before a predetermined time. This advance time is called the transmission time (TA). This advance time allows the terminal device to communicate with the base station at the correct moment.

[0074] During cell handover, to reduce service interruption caused by the terminal device acquiring the target cell's TA, the 3GPP standard supports multiple optional solutions, including early-random access channel (RACH) and non-early-RACH.

[0075] Among them, the early-RACH scheme allows the UE to obtain the neighboring cell TA before switching, specifically including: PDCCH-ordered CFRA, that is,

[0076] The serving cell sends a PDCCH, designating the UE to initiate a contention-free random access (CFRA) procedure to the target cell. The network does not respond to the random access response (RAR), so the UE does not need to wait for or monitor the RAR, thereby reducing interruption. In this case, the TA is carried by the CSC.

[0077] The non-early-RACH solution may include two branches: a method in which the terminal device determines the TA by itself before switching, and a method in which the RACH is sent after switching to obtain the TA.

[0078] (1) The terminal device obtains the TA before cell switching, that is, the terminal device can calculate the TA by measuring the time difference between the downlink arrival time of the serving cell and the target cell. In one possible implementation, the terminal device can obtain the TA by calculating the following formula:

[0079] Target_TA=Source_TA+2RSTD+TA_NT_Adj_Factor

[0080] Among them, Target_TA can represent the TA value of the target cell that the terminal needs to obtain, Source_TA can be the TA used by the terminal device to send the uplink signal in the serving cell; RSTD can represent the arrival time difference between the downlink reference signal arrival time of the terminal device receiving the current cell (current serving cell) and the downlink reference signal of the neighboring cell; TA_NT_Adj_Factor can represent a compensation amount sent by the network device to the terminal device for calculating TA, and its physical meaning can be the downlink transmission time difference between the two cells.

[0081] (2) The terminal device sends RACH to obtain the TA after the cell is switched. That is, the terminal device obtains the TA in the new cell through the RACH process after receiving the switching command. This process cannot significantly reduce the interruption caused by the UE initiating RACH to obtain the TA after the switching command is issued (the UE needs to wait for the RACH timing of the target cell after the switching command, and needs to wait for the network response after sending the preamble. During this period, the UE is neither connected to the serving cell nor to the new cell). Therefore, this solution is a backup plan.

[0082] The following describes the process of non-contention (also called contention-free) random access by taking FIG. 1 as an example.

[0083] As shown in Figure 1, since conflict resolution is not required, the gNodeB can identify which terminal device sends the random access request (i.e., information #1 in Figure 1, which includes the preamble) based on the pre-assigned preamble and RACH resource location. At the same time, the gNodeB can estimate the TA based on the preamble in information #1 and send information #2 to the terminal device, which includes the TA, so that the terminal device completes the random access process according to the TA, ensuring that the terminal device can communicate with the gNodeB at the correct time.

[0084] However, currently in the cell switching process, the terminal device can obtain the TA in any one or more of a variety of ways based on the configuration or indication of the serving cell. For example, in the scenario shown in Figure 2, the terminal device can obtain the TA in any one or more of a variety of ways, including: the terminal device can autonomously obtain the TA through the configuration of the serving cell (i.e., the configuration to obtain the TA in Figure 2), obtain the TA in the serving cell through contention-free random access (i.e., the PDCCH command in Figure 2), or obtain the TA through a switching command (i.e., the CSC in Figure 2, the TA can be the TA previously obtained based on the RACH triggered by the PDCCH, or the TA obtained by directly setting the TA value to 0 by the serving cell, or the TA value indicated by the serving cell is the same as the TA used by the current serving cell). When multiple ways of obtaining the TA coexist, the terminal device needs to determine the TA for communicating with the target cell to ensure the quality and stability of the communication.

[0085] The embodiments of the present application provide a method and apparatus for determining a timing advance TA, so that a terminal device can correctly determine the TA for communicating with a target cell when multiple methods for obtaining the TA coexist, thereby ensuring the quality and stability of communication of the terminal device.

[0086] FIG3 is a diagram of a system architecture applicable to the method for determining the timing advance TA provided in an embodiment of the present application.

[0087] As shown in Figure 3, the architecture includes a terminal device 10 and a network device 20, with which the terminal device 10 can communicate. The terminal device 10 may include a processor 101, a memory 102, and a transceiver 103. The transceiver 103 includes a transmitter 1031, a receiver 1032, and an antenna 1033. The network device 20 may include a processor 201, a memory 202, and a transceiver 203. The transceiver 203 includes a transmitter 2031, a receiver 2032, and an antenna 2033. Receiver 1032 may be configured to receive transmission control information via antenna 1033, and transmitter 1031 may be configured to send transmission feedback information to the network device 20 via antenna 1033. Transmitter 2031 may be configured to send transmission control information to the terminal device 10 via antenna 2033, and receiver 2032 may be configured to receive transmission feedback information sent by the terminal device 10 via antenna 2033.

[0088] FIG4 is a schematic diagram of an application scenario of the method for determining the timing advance TA provided in an embodiment of the present application.

[0089] As shown in Figure 4, this scenario includes a network device and a terminal device. The network device can transmit data or control instructions to the terminal device. After receiving the transmission data or control instructions sent by the network device, the terminal device can report the measurement results of the reference signal (corresponding to the beam) based on the configuration information of the network device, thereby switching the service beam of the terminal device. Among them, multiple carriers can be configured in each cell. The carrier can be the carrier component (CC) in Figure 4. The carrier can also be called a service cell in the protocol. In addition, the scenario shown in Figure 4 is a scenario based on a single terminal device and network device as an example. This scenario can also include multiple terminal devices and multiple network devices.

[0090] FIG5 is a schematic flowchart of a method for determining a timing advance TA provided in an embodiment of the present application. The method 500 may be applied to the system architecture shown in FIG3 and the application scenario shown in FIG4 . The method 500 may include the following steps.

[0091] S501, the terminal device receives a cell switching command sent by the serving cell.

[0092] Optionally, the cell switching command may be a CSC, and the cell switching command may carry the first TA or may not carry the first TA.

[0093] Optionally, the first TA included in the cell switching command may refer to a TA value, or may indicate TA=0, or may be used to indicate that the TA value is equal to the current serving cell.

[0094] In one embodiment, before step S501, method 500 further includes: the terminal device sending capability information to the serving cell, where the capability information indicates the number of TAs that the terminal device can acquire or maintain from the target cell. The capability information can be associated with the terminal device's subsequent TA selection behavior, facilitating the terminal device's selection of a qualified TA to ensure communication quality and stability.

[0095] S502: The terminal device determines whether the cell switching command includes the first TA.

[0096] S503, if the cell switching command includes the first TA, the terminal device uses the first TA to communicate with the target cell; if the cell switching command does not include the first TA, the terminal device uses the second TA or the third TA to communicate with the target cell.

[0097] The second TA is a TA determined by the terminal device based on the reference signals of the serving cell and the target cell, and the third TA is a TA determined by the terminal device when initiating a random access process to the target cell after receiving a cell switching command.

[0098] Among them, the service cell may refer to the cell to which the terminal device is currently connected. By establishing a connection with the service cell, the terminal device can perform communication activities such as data transmission and voice calls; the target cell may refer to the cell that is connected and communicated with the terminal device after cell switching.

[0099] Optionally, the second TA may be specifically determined based on a time difference between arrival of downlink reference signals of the serving cell and the target cell.

[0100] Optionally, the random access procedure for acquiring the third TA may include a contention-based random access procedure or a contention-free random access procedure.

[0101] In an embodiment of the present application, after receiving a cell switching command, the terminal device can determine whether the cell switching command includes the first TA, thereby determining the TA (first TA, second TA or third TA) for communicating with the target cell. In this way, when multiple methods of obtaining TA coexist, the TA for communicating with the target cell can be correctly determined, thereby ensuring the quality and stability of communication of the terminal device.

[0102] In one embodiment, if the cell handover command includes a first TA, before the terminal device uses the first TA to communicate with the target cell, method 500 further includes: determining that a first timer has not timed out, where the first timer is a timer that starts after the terminal device sends a random access request to the target cell. In this way, the terminal device can further verify the validity of the first TA when the cell handover command includes the first TA, thereby helping the terminal device correctly select a TA for communicating with the target cell.

[0103] Optionally, the first timer may be a timer that starts timing at a point in time after the terminal device initiates the last random access request triggered by the PDCCH.

[0104] Optionally, the first timer may be configured by the network device to the terminal device.

[0105] Alternatively, if the first timer expires, the terminal device may not use the first TA to communicate with the target cell.

[0106] In one embodiment, if the cell switching command does not include the first TA, and the second TA is obtained by the terminal device measuring the synchronization signal blocks SSB of the serving cell and the target cell at the first moment, the terminal device can select the second TA to communicate with the target cell if the second timer has not timed out. The second timer is a timer that starts counting from the first moment. In this way, if the second TA is not included in the cell switching command, the terminal device can further verify the validity of the second TA, thereby helping the terminal device to correctly select the TA for communicating with the target cell, thereby ensuring stable and high-quality communication between the terminal device and the target cell.

[0107] The second timer can be understood as the time to maintain the timing from drifting (for example, to meet the error requirements specified by the protocol) after a measurement. The expiration of the second timer can be understood as the second TA may no longer be accurate and no longer suitable for data communication with the target cell after the handover.

[0108] Optionally, when the second timer expires, the terminal device may re-measure the SSBs of the serving cell and the target cell at a second moment, where the second moment is later than the first moment. Before the second moment, the second TA obtained by the terminal device is temporarily invalid.

[0109] In one embodiment, if the cell handover command does not include the first TA and the second timer expires, the terminal device may select to use the third TA to communicate with the target cell. This can prevent the terminal device from incorrectly selecting the TA for communication with the target cell, which may result in loss of transmitted data.

[0110] In one embodiment, if the cell handover command does not include the first TA, and the random access process corresponding to the third TA is a contention-free random access process, the terminal device can use the third TA to communicate with the target cell. In this way, when multiple methods for obtaining a TA coexist, the terminal device can correctly select the TA to be used, ensuring that the terminal device can maintain efficient communication with the target cell in a changing communication environment.

[0111] In one embodiment, when the handover command does not include a TA, the terminal device may communicate with the target cell using the second TA or the third TA according to a predefined priority.

[0112] Optionally, the above priority may be: when there are CFRA resources after cell switching, the terminal device may obtain the third TA in the CFRA process after cell switching and use the third TA to communicate with the target cell.

[0113] Optionally, the above priority may be: when there are no CFRA resources after cell switching, the terminal device may use a contention random access process to obtain a third TA after cell switching, and use the second TA to communicate with the target cell.

[0114] Optionally, the above priority may be: when there are no CFRA resources after cell switching, the terminal device may use a contention random access process to obtain a third TA after cell switching, and use the third TA to communicate with the target cell.

[0115] Optionally, the above priority may be a priority configured by the network device, or a priority configured for each cell / TAG.

[0116] FIG6 is a schematic flowchart of another method for determining a timing advance TA provided in an embodiment of the present application. The method 600 may be applied to the system architecture shown in FIG3 and the application scenario shown in FIG4 . The method 600 may include the following steps.

[0117] S601, the terminal device receives a cell switching command sent by the serving cell.

[0118] Optionally, the cell switching command may be a CSC, and the cell switching command may carry the first TA.

[0119] Optionally, the first TA included in the cell switching command may refer to a TA value, or may indicate TA=0, or may be used to indicate that the TA value is equal to the current serving cell.

[0120] In one embodiment, before step S601, method 600 further includes: the terminal device sending capability information to the serving cell, where the capability information is used to indicate the number of TAs that the terminal device can acquire or maintain from the target cell. The capability information can be associated with the terminal device's subsequent TA selection behavior, facilitating the terminal device's need to determine a TA for communication with the target cell to ensure the quality and stability of the terminal device's communication.

[0121] S602, the terminal device obtains the third TA.

[0122] The third TA is the TA determined by the terminal device when it initiates a contention-free random access process to the target cell after receiving the cell switching command.

[0123] S603, the terminal device uses the third TA to communicate with the target cell.

[0124] Alternatively, when the cell switching command does not include the first TA, the terminal device may also communicate with the target cell according to the third TA.

[0125] In an embodiment of the present application, even if the cell switching command includes a first TA, the terminal device can also use the third TA determined by the contention-free random access process to communicate with the target cell. In this way, when multiple methods of obtaining TA coexist, the TA for communicating with the target cell can be correctly determined, thereby ensuring the quality and stability of communication of the terminal device.

[0126] In one embodiment, before step S603, method 600 further includes: the terminal device determining that a first timer has timed out, where the first timer is a timer that starts after sending a random access request to the target cell. In this way, the terminal device can avoid using the invalid first TA to communicate with the target cell, thereby avoiding loss of transmitted data.

[0127] FIG7 is a schematic flowchart of another method for determining a timing advance TA provided in an embodiment of the present application. Method 700 may be a specific description of each step in method 500 and method 600. Method 700 may include the following steps.

[0128] S701, the serving cell sends capability request information to the terminal device.

[0129] The serving cell may refer to the cell to which the terminal device is currently connected. The terminal device may conduct communication activities such as data transmission and voice calls by establishing a connection with the serving cell.

[0130] S702, the terminal device sends capability information to the serving cell.

[0131] Exemplarily, the capability information is used to indicate the number of TAs of a target cell or non-serving cell that the terminal device can acquire or maintain.

[0132] Optionally, the capability in the above capability information may refer to the number of timing advance groups (TAGs) or the number of TAs that the terminal device can maintain for each target cell; it may be the total number of TAs acquired by each terminal device for the target cell, the total number of TAs that the terminal device can acquire or maintain in each frequency band (band), or the total number of TAs acquired or maintained by the terminal device in each frequency range (FR), wherein the total number of TAs acquired or maintained by the terminal device in each FR may include the TA of the current serving cell, or may not include the TA of the current serving cell.

[0133] Optionally, method 700 may skip steps S701 and S702 and directly proceed to step S703.

[0134] S703, the serving cell sends TA acquisition indication information to the terminal device.

[0135] Among them, the TA acquisition indication information is used to indicate which reference signal or signals the terminal device uses to obtain the corresponding TA, and the TA acquisition indication information may include: a neighboring cell identifier, which may be a synchronization signal block (SSB) index, a neighboring cell channel state information reference signal (CSI-RS) resource or resource set identifier, or one or more of a measurement resource identifier associated with a neighboring cell reference signal.

[0136] Optionally, the TA acquisition indication information further includes: a TAG identifier of the acquired TA in an associated neighboring cell.

[0137] It should be understood that the above-mentioned associated neighboring cell may refer to a target cell corresponding to a terminal cell after cell switching.

[0138] Optionally, the TA acquisition indication information may also include: the time difference between the downlink transmission time of the target reference signal or cell and the downlink transmission time of the current serving cell. In one possible implementation, the calculation method of the above time difference in the protocol may only define a formula; wherein the above formula may include an offset, and the physical meaning of the offset may or may not be given by the protocol. The offset item in the calculation method or formula given by the protocol is optional, or the item may not exist. If the network device does not configure the offset for the terminal device, the default value of the offset may be 0.

[0139] Optionally, during the process of acquiring the TA, the terminal device may perform rate matching on the data transmission of the serving cell or set a measurement gap during the measurement period. Rate matching may refer to the presence of reference signal resources to be measured in the scheduled continuous time-frequency resources of the terminal device, so that the data signal cannot be mapped to the resource grid where the reference signal exists; and a measurement gap may refer to a time window set for measurement, during which the terminal device does not expect to communicate with the serving cell.

[0140] In one embodiment, if the TA acquired by the terminal device according to the TA acquisition indication information exceeds the maximum capability limit of the terminal device, the terminal device releases the earliest acquired TA under the same capability limit.

[0141] For example, the terminal device can maintain a maximum of two TAs. If the serving cell instructs the terminal device that an additional TA needs to be acquired, the terminal device can release the earlier acquired TA of the two maintained TAs.

[0142] Optionally, if the protocol allows signaling to configure multiple TAs at one time, the terminal device can release the TA with the smaller index identifier, where the index identifier can include an RS ID or a physical cell identity (PCI). The above process can be specifically indicated by a medium access control-control element (MAC-CE), which can include multiple reference signal identifiers for TA measurement and / or multiple corresponding cell identifiers.

[0143] In one embodiment, after performing step S703, the terminal device may no longer acquire TAs that exceed the capability reporting quantity until it receives TA acquisition deactivation information sent by the serving cell.

[0144] Optionally, TA acquisition deactivation information can display and instruct the terminal device which TA to release or stop maintaining. The released TA will no longer be allowed to be used when the terminal device subsequently switches cells. That is, in the subsequent process, if the TA is not included in the CSC, the terminal device can initiate a RACH process after the cell switch.

[0145] S704: The target cell sends a measurement reference signal to the terminal device.

[0146] Among them, the terminal device can autonomously obtain the TA based on the measurement reference signal and the reference signal of the serving cell, and the TA autonomously obtained by the terminal device can be the second TA in method 500.

[0147] S705, the terminal device sends confirmation information of successful TA acquisition to the serving cell.

[0148] Optionally, if in a subsequent process, the TA obtained by the terminal device becomes invalid (for example, the designated SSB is no longer measured, causing the TA to be no longer applicable), the terminal device may report the TA invalidation information to the serving cell.

[0149] S706, the serving cell sends a cell switching command CSC to the terminal device.

[0150] Optionally, the CSC may carry a TA or may not carry a TA. When the CSC carries a TA, the TA may be the first TA in method 500 and method 600.

[0151] S707, the terminal device determines the TA after the cell switching according to the rules.

[0152] In one embodiment, the above rules may be: when TA is included in the CSC, the terminal device may determine the TA according to the indication of the CSC, and the TA value may be obtained based on the PDCCH ordered RACH process of contention free random access-free (RAR-free), obtained by indicating TA=0, or obtained by indicating that the TA value is equal to the current serving cell. The embodiment of the present application does not limit the method for obtaining the TA value.

[0153] In one embodiment, the above rule may be: when the CSC does not include a TA, and the target cell has a maintained TA (corresponding to the terminal device autonomously obtaining the TA), the terminal device may use the autonomously obtained TA to communicate with the target cell. When the terminal device uses the autonomously obtained TA for communication, the serving cell may be aware that the terminal device has successfully autonomously obtained the TA, and the serving cell may need to explicitly instruct the terminal device to use the TA through the CSC.

[0154] In one embodiment, the above rules may be: when the CSC does not include a TA and the terminal device does not autonomously obtain a TA, the terminal device may first perform a cell switch, and after the cell switch, the terminal device obtains the TA through a RACH process, which may be the third TA in method 500 and method 600.

[0155] Optionally, in the above-mentioned embodiments, when CFRA resources are configured in the RRC information sent by the serving cell to the terminal device, regardless of whether the terminal device has a valid TA, after cell switching, the terminal device can initiate a CFRA process to obtain a TA, which can be the third TA in method 500 and method 600, or the terminal device can ignore the CFRA resources and release them, and use the autonomously acquired TA.

[0156] In step S707, for the same target cell, when multiple methods of obtaining the TA exist simultaneously, the terminal device may only use one of the methods to obtain the TA.

[0157] For example, when the TA obtained autonomously by the terminal device and the TA indicated by the PDCCH-ordered CFRA exist at the same time, the terminal device may abandon the TA obtained autonomously instead of simultaneously using the TAs obtained in the above two ways.

[0158] In step S707, the rule followed by the terminal device may be the priority defined in the agreement between the terminal device and the serving cell.

[0159] Optionally, the above priority may be: when the CSC includes a TA, the terminal device preferentially adopts the TA indicated by the CSC and ignores the TA obtained autonomously by the terminal device.

[0160] Optionally, the above priority may be: when there are CFRA resources after cell switching, the terminal device may first perform cell switching, initiate a CFRA process to obtain TA after switching, and ignore the TA obtained autonomously by the terminal device.

[0161] Optionally, the above priority may be: when the TA is included in the CSC and there are CFRA resources after the cell switching, the terminal device adopts the autonomously acquired TA.

[0162] Optionally, the priority may be: when the terminal device is able to autonomously obtain the TA, and when there are CFRA resources after the cell switching, the terminal device uses the TA obtained by initiating the CFRA process after the cell switching.

[0163] Optionally, the above priority may be: the terminal device can autonomously obtain the TA, and when there are no CFRA resources after the cell switching, the terminal device obtains the TA through the RACH process after the cell switching.

[0164] Optionally, the priority may be: the TA that the terminal device can autonomously acquire, and when there are no CFRA resources after cell switching, the terminal device uses the autonomously acquired TA.

[0165] Optionally, the above priority may be a priority configured by the network device, or a priority configured for each cell / TAG.

[0166] Before step S706, if the serving cell configures a first timer for the terminal device, in step S707, the terminal device may determine the TA to be used after the cell switching based on the timeout condition and rules of the first timer.

[0167] In one embodiment, for a target cell, when the terminal device autonomously obtains a TA, the terminal device may send a random access request to the target cell after receiving the DCI. The random access request is used to instruct the terminal device to send a CFRA. The first timer starts at the time point after the last random access request initiated by the terminal device. (Since a random access request sent by a terminal device once may not be received by the target cell, the terminal device may send multiple random access requests for the same target cell).

[0168] In one embodiment, when the CSC sent by the serving cell to the terminal device includes a TA and the first timer has not timed out, the terminal device may use the TA indicated by the CSC as the TA after the cell handover. In other words, the priority of the TA indicated by the CSC is higher than the priority of the TA obtained autonomously by the terminal device.

[0169] In one embodiment, the CSC sent by the serving cell to the terminal device includes a TA, and when the first timer times out, the terminal device may use the autonomously acquired TA as the TA after the cell switching.

[0170] In one embodiment, when the CSC sent by the serving cell to the terminal device includes a TA, the first timer times out, and the terminal device does not autonomously obtain the TA (or is unable to autonomously obtain the TA), the terminal device may initiate a RACH process to obtain the TA after performing a cell switch, that is, the terminal device may ignore the TA included in the CSC at this time.

[0171] In step S703, if the TA autonomously obtained by the terminal device adopts a one-time measurement method, that is, the terminal device performs measurement calculation based on the SSB of a neighboring cell (target cell) instead of periodic measurement, the terminal device can obtain a second timer, which is used to represent the validity period of the TA obtained after the terminal device performs a measurement.

[0172] Optionally, the timeout of the above-mentioned second timer can be understood as the time during which the terminal device maintains the timing without drifting after performing a measurement, and the time without drift can be understood as the time during which the error specified in the protocol is satisfied; the timeout of the above-mentioned second timer can be understood as the TA obtained by the terminal device is inaccurate, and the TA cannot be applied to the communication between the terminal device and the target cell after the cell switching.

[0173] Optionally, after the above-mentioned second timer times out, the terminal device can wait until the next neighboring cell period SSB to re-measure, and before re-measurement, the TA is temporarily invalid.

[0174] Optionally, if the terminal device cannot transmit data in the serving cell when measuring TA, the terminal device can determine the time domain resources that need to be punctured for measurement based on the timer and the neighboring cell SSB cycle position. In this way, the terminal device can avoid interfering with the data transmission of the serving cell while ensuring its own synchronization with the serving cell.

[0175] The above describes the method for determining the timing advance TA provided in the embodiment of the present application. The following describes the apparatus and device of the embodiment of the present application in conjunction with Figures 8 and 9 respectively.

[0176] Figure 8 is a schematic diagram of an apparatus 800 for determining a timing advance (TA) according to an embodiment of the present application. The apparatus 800 may include a transceiver unit 810, a storage unit 820, and a processing unit 830. The transceiver unit 810 is configured to receive and send instructions and / or data. The transceiver unit 810 may also be referred to as a communication interface or communication unit. The storage unit 820 is configured to implement corresponding storage functions and store corresponding instructions and / or data. The processing unit 830 may read the instructions and / or data in the storage unit to enable the apparatus 800 to implement the aforementioned method for determining a timing advance (TA).

[0177] As a design, the device 800 includes: a transceiver unit 810, used to receive a cell switching command sent by a serving cell; a processing unit 830, used to: determine whether the cell switching command includes a first TA; if the cell switching command includes the first TA, use the first TA to communicate with the target cell; if the cell switching command does not include the first TA, use the second TA or the third TA to communicate with the target cell, the second TA is a TA determined by the terminal device based on the reference signals of the serving cell and the target cell, and the third TA is a TA determined by the terminal device when initiating a random access process to the target cell after receiving the cell switching command.

[0178] In a possible implementation, the processing unit 830 is further configured to determine that a first timer has not timed out, where the first timer is a timer that starts timing after the terminal device sends a random access request to the target cell.

[0179] In one possible implementation, the second TA is obtained by the terminal device measuring the synchronization signal block SSB of the serving cell and the target cell at the first moment; the processing unit 830 is specifically used to use the second TA to communicate with the target cell if the second timer has not timed out, and the second timer is a timer that starts counting from the first moment.

[0180] In a possible implementation, the processing unit 830 is specifically configured to use a third TA to communicate with the target cell if the second timer times out.

[0181] In a possible implementation, the processing unit 830 is specifically configured to use a third TA to communicate with the target cell if the random access procedure is a contention-free random access procedure.

[0182] In a possible implementation, the transceiver unit 810 is further configured to send capability information to the serving cell, where the capability information is used to indicate the number of TAs that the terminal device can acquire or maintain from the target cell.

[0183] As a design, the device 800 includes: a transceiver unit 810, used to receive a cell switching command sent by a serving cell, wherein the cell switching command includes a first TA; a processing unit 830, used to: obtain a third TA, wherein the third TA is a TA determined by the terminal device when initiating a contention-free random access process to the target cell after receiving the cell switching command; and communicate with the target cell according to the third TA.

[0184] In a possible implementation, the processing unit 830 is further configured to determine whether a first timer has timed out, where the first timer is a timer that starts timing after a random access request is sent to a target cell.

[0185] In a possible implementation, the transceiver unit 810 is further configured to send capability information to the serving cell, where the capability information is used to indicate the number of TAs that the terminal device can acquire or maintain from the target cell.

[0186] As a design, the device 800 includes: a processing unit 830, used to: obtain a second TA and a third TA, wherein the second TA is a TA determined by the terminal device based on the reference signals of the serving cell and the target cell, and the third TA is a TA determined by the terminal device when initiating a random access process to the target cell after receiving the cell switching command; and determine a target TA for communicating with the target cell according to preset rules.

[0187] FIG9 is a schematic diagram of another apparatus 900 for determining a timing advance TA provided in an embodiment of the present application.

[0188] The apparatus 900 includes a memory 910, a processor 920, and a communication interface 930. The memory 910, processor 920, and communication interface 930 are connected via an internal connection path. The memory 910 is used to store instructions, and the processor 920 is used to execute the instructions stored in the memory 910 to control the communication interface 930 to obtain information, so that the apparatus 900 implements the aforementioned method for determining the timing advance TA. Optionally, the memory 910 can be coupled to the processor 920 via an interface or integrated with the processor 920.

[0189] It should be noted that the communication interface 930 may be a transceiver such as, but not limited to, a transceiver. The communication interface 930 may also include an input / output interface.

[0190] The processor 920 stores one or more computer programs, which include instructions. When the instructions are executed by the processor 920, the apparatus 900 executes the method for determining the timing advance TA in the above embodiments.

[0191] It should be understood that in the embodiments of the present application, the processor may be a central processing unit (CPU), or may be 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 any conventional processor.

[0192] It should also be understood that in the embodiments of the present application, the memory may include read-only memory and random access memory, and provide instructions and data to the processor. A portion of the processor may also include non-volatile random access memory. For example, the processor may also store device type information.

[0193] During implementation, each step of the above method can be completed by an integrated logic circuit of the hardware in the processor 920 or by instructions in the form of software. The method disclosed in conjunction with the embodiments of the present application can be directly embodied as being executed by a hardware processor, or can be executed by a combination of hardware and software modules in the processor. The software module can be located in a mature storage medium in the art, such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 910, and the processor 920 reads the information in the memory 910 and completes the steps of the above method in combination with its hardware. To avoid repetition, it will not be described in detail here.

[0194] Optionally, the communication interface 930 in FIG. 9 may implement the transceiver unit 810 in FIG. 8 , the memory 910 in FIG. 9 may implement the storage unit 820 in FIG. 8 , and the processor 920 in FIG. 9 may implement the processing unit 830 in FIG. 8 .

[0195] An embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a program code. When the computer program code is executed on a computer, the computer executes any one of the methods in FIG. 5 to FIG. 7 .

[0196] An embodiment of the present application further provides a computer program product, which includes a computer program. When the computer program is executed, the computer executes any one of the methods in Figures 5 to 7 above.

[0197] An embodiment of the present application further provides a chip, comprising: a circuit, wherein the circuit is used to execute any one of the methods in FIG. 5 to FIG. 7 above.

[0198] An embodiment of the present application also provides a terminal device, including: any one of the devices for determining timing advance as shown in Figure 8 or Figure 9.

[0199] Those skilled in the art will appreciate that the units and algorithm 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 beyond the scope of this application.

[0200] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0201] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interface, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0202] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0203] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0204] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes 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.

[0205] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A method for determining a timing advance TA, characterized in that: The method comprises: Receiving a cell switching command sent by a serving cell; Determining whether the cell switching command includes a first TA; If the cell switching command includes the first TA, using the first TA to communicate with the target cell; If the cell switching command does not include the first TA, the second TA or the third TA is used to communicate with the target cell, the second TA is a TA determined by the terminal device based on the reference signals of the serving cell and the target cell, and the third TA is a TA determined by the terminal device when initiating a random access process to the target cell after receiving the cell switching command.

2. The method according to claim 1, characterized in that Before communicating with the target cell using the first TA, the method further includes: Determine that a first timer has not timed out, where the first timer is a timer that starts timing after the terminal device sends a random access request to the target cell.

3. The method according to claim 1, characterized in that The second TA is obtained by the terminal device measuring the synchronization signal blocks SSB of the serving cell and the target cell at a first moment, and the communicating with the target cell using the second TA or the third TA includes: If the second timer has not timed out, the second TA is used to communicate with the target cell, and the second timer is a timer that starts counting from the first moment.

4. The method according to claim 3, characterized in that The communicating with the target cell using the second TA or the third TA includes: If the second timer times out, the third TA is used to communicate with the target cell.

5. The method according to claim 1, characterized in that The communicating with the target cell using the second TA or the third TA includes: If the random access procedure is a contention-free random access procedure, the third TA is used to communicate with the target cell.

6. The method according to any one of claims 1 to 5, characterized in that: Before the receiving the cell switching command sent by the serving cell, the method further includes: Capability information is sent to the serving cell, where the capability information is used to indicate the number of TAs that the terminal device can acquire or maintain from the target cell.

7. The method according to any one of claims 1 to 6, characterized in that The method further comprises: receiving configuration information sent by a network device, where the configuration information is used to instruct the terminal device to autonomously acquire the second TA through configuration of the serving cell; The second TA is determined according to the configuration information.

8. A method for determining a timing advance TA, characterized in that: The method comprises: receiving a cell switching command sent by a serving cell, wherein the cell switching command includes a first TA; Acquire a third TA, where the third TA is a TA determined by the terminal device initiating a contention-free random access process to the target cell after receiving the cell switching command; Communicate with the target cell according to the third TA.

9. The method according to claim 8, characterized in that Before communicating with the target cell according to the third TA, the method further includes: It is determined that a first timer has timed out, where the first timer is a timer that starts timing after a random access request is sent to the target cell.

10. The method according to claim 8 or 9, characterized in that Before the receiving the cell switching command sent by the serving cell, the method further includes: Send capability information to the serving cell, where the capability information is used to indicate the number of TAs that the terminal device can acquire or maintain from the target cell.

11. A device for determining a timing advance TA, characterized in that: The device comprises: A transceiver unit, configured to receive a cell switching command sent by a serving cell; A processing unit for: Determining whether the cell switching command includes a first TA; If the cell switching command includes the first TA, using the first TA to communicate with the target cell; If the cell switching command does not include the first TA, the second TA or the third TA is used to communicate with the target cell, the second TA is a TA determined by the terminal device based on the reference signals of the serving cell and the target cell, and the third TA is a TA determined by the terminal device when initiating a random access process to the target cell after receiving the cell switching command.

12. The device according to claim 11, characterized in that The processing unit is further used to determine that a first timer has not timed out, where the first timer is a timer that starts timing after the terminal device sends a random access request to the target cell.

13. The device according to claim 11, characterized in that The second TA is obtained by the terminal device measuring the synchronization signal blocks SSB of the serving cell and the target cell at the first moment; The processing unit is specifically configured to use the second TA to communicate with the target cell if the second timer has not timed out, and the second timer is a timer that starts counting from the first moment.

14. The device according to claim 13, characterized in that The processing unit is specifically configured to use the third TA to communicate with the target cell if the second timer times out.

15. The device according to claim 11, characterized in that The processing unit is specifically configured to use the third TA to communicate with the target cell if the random access procedure is a contention-free random access procedure.

16. The device according to any one of claims 11 to 15, characterized in that The transceiver unit is further used to send capability information to the serving cell, where the capability information is used to indicate the number of TAs that the terminal device can obtain or maintain from the target cell.

17. The device according to any one of claims 11 to 16, characterized in that The transceiver unit is further used to receive configuration information sent by a network device, where the configuration information is used to instruct the terminal device to autonomously acquire the second TA through the configuration of the serving cell; The processing unit is further used to determine the second TA according to the configuration information.

18. A device for determining a timing advance TA, characterized in that: The device comprises: a transceiver unit, configured to receive a cell switching command sent by a serving cell, wherein the cell switching command includes a first TA; A processing unit for: Acquire a third TA, where the third TA is a TA determined by the terminal device initiating a contention-free random access process to the target cell after receiving the cell switching command; Communicate with the target cell according to the third TA.

19. The device according to claim 18, characterized in that The processing unit is further used to determine that a first timer has timed out, where the first timer is a timer that starts timing after a random access request is sent to the target cell.

20. The device according to claim 18 or 19, characterized in that The transceiver unit is further used to send capability information to the serving cell, where the capability information is used to indicate the number of TAs that the terminal device can obtain or maintain from the target cell.

21. A device for determining a timing advance TA, characterized in that: include: A processor and a memory, wherein the processor is coupled to the memory and is configured to read and execute instructions in the memory to perform the method according to any one of claims 1 to 7.

22. A device for determining a timing advance TA, characterized in that: include: A processor and a memory, wherein the processor is coupled to the memory and is configured to read and execute instructions in the memory to perform the method according to any one of claims 8 to 10.

23. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a program code, and when the computer program code is executed on a computer, the computer is caused to execute the method according to any one of claims 1 to 10.

24. A chip, characterized in that: include: A circuit for executing the method according to any one of claims 1 to 10.

25. A terminal device, characterized in that: include: A device as claimed in any one of claims 11 to 22.

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