Clock synchronization method, device and storage medium

Abstract

The present application proposes a clock synchronization method, device and storage medium, a clock synchronization method, including: if the source base station determines that the UE meets the switching conditions, the source base station sends a switching request to the target base station, and the switching request includes information requesting a precise clock; the source base station receives the precise clock information of the target base station.

Description

Technical Field

[0001] The present application relates to a wireless communication network, for example, to a clock synchronization method, device and storage medium. Background Art

[0002] In the New Radio (NR) standard, given the mobility of terminals and other factors, the serving cell currently accessed by the terminal may switch at any time. During the handover process, if the handover is to a neighboring cell across base stations, the clock of the neighboring cell may be out of sync with the clock of the current cell. Therefore, it is necessary to consider the delay compensation between the target cell and the current serving cell. In other words, the clock information of the target cell must be notified to the base station during the handover process.

[0003] Therefore, when performing a cell handover between base stations, the target cell and the terminal must achieve precise clock synchronization, with minimal transmission latency. To achieve this, the target base station must transmit accurate clock information to the terminal. Therefore, how to provide the terminal with the target base station's precise clock information, or the clock difference between the terminal and the target base station, and achieve accurate clock synchronization between the target cell and the terminal, remains a pressing issue. Summary of the Invention

[0004] The present application provides a clock synchronization method, device and storage medium, which enable a UE to achieve precise clock synchronization with a target base station after cell switching.

[0005] In a first aspect, an embodiment of the present application provides a clock synchronization method, comprising:

[0006] If the source base station determines that the UE meets the handover conditions, the source base station sends a handover request to the target base station, where the handover request includes information requesting a precise clock.

[0007] The source base station receives the precise clock information of the target base station.

[0008] In a second aspect, an embodiment of the present application provides a clock synchronization method, including:

[0009] The UE receives first RRC reconfiguration information sent by the source base station, where the first RRC reconfiguration information includes a clock difference, where the clock difference is a difference between clocks of the target base station and the source base station.

[0010] In a third aspect, an embodiment of the present application provides a clock synchronization method, including:

[0011] The AMF receives a handover request message including information requesting a precise clock sent by the source base station;

[0012] The AMF sends a handover request including information requesting a precise clock to the target base station;

[0013] The AMF receives the second signaling sent by the target base station and carrying the precise clock information of the target base station;

[0014] The AMF sends a third signaling carrying the precise clock information of the target base station to the source base station.

[0015] In a fourth aspect, an embodiment of the present application provides a clock synchronization method, including:

[0016] The target base station receives the handover request message including the request for precise clock information sent by the source base station, the handover request message including the request for precise clock information sent by the AMF, or the RRC-free re-establishment request message including the request for precise clock information sent by the user equipment UE;

[0017] The target base station sends precise clock information to the source base station through the first signaling, sends precise clock information to the AMF through the third signaling, or sends precise clock information to the UE through the RRC response message.

[0018] In a fifth aspect, an embodiment of the present application provides a base station, comprising: a processor and a memory, wherein the processor is configured to run program instructions stored in the memory to execute the clock synchronization method according to the first aspect.

[0019] In a sixth aspect, an embodiment of the present application provides a UE, comprising: a processor and a memory, wherein the processor is configured to run program instructions stored in the memory to execute the clock synchronization method according to the second aspect.

[0020] In the seventh aspect, an embodiment of the present application provides an AMF, comprising: a processor and a memory, the processor being configured to run program instructions stored in the memory to execute the clock synchronization method according to the third aspect.

[0021] In an eighth aspect, an embodiment of the present application provides a base station, comprising: a processor and a memory, wherein the processor is configured to run program instructions stored in the memory to execute the clock synchronization method according to the fourth aspect.

[0022] In a ninth aspect, an embodiment of the present application provides a storage medium storing a computer program, which implements the clock synchronization method according to the first to fourth aspects when the computer program is executed by a processor. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A flowchart of a clock synchronization method provided by an embodiment;

[0024] Figure 2 A flowchart of another clock synchronization method provided by an embodiment;

[0025] Figure 3 A flowchart of another clock synchronization method provided by an embodiment;

[0026] Figure 4 A flowchart of another clock synchronization method provided by an embodiment;

[0027] Figure 5 A flowchart of another clock synchronization method provided by an embodiment;

[0028] Figure 6 A flowchart of another clock synchronization method provided by an embodiment;

[0029] Figure 7 An interactive flow chart of a clock synchronization method provided by an embodiment;

[0030] Figure 8 An interactive flow chart of another clock synchronization method provided by an embodiment;

[0031] Figure 9 An interactive flow chart of another clock synchronization method provided by an embodiment;

[0032] Figure 10 An interactive flow chart of another clock synchronization method provided by an embodiment;

[0033] Figure 11 An interactive flow chart of another clock synchronization method provided by an embodiment;

[0034] Figure 12 A schematic structural diagram of a clock synchronization device provided by an embodiment;

[0035] Figure 13 A schematic structural diagram of another clock synchronization device provided by an embodiment;

[0036] Figure 14 A schematic diagram of another clock synchronization device provided in an embodiment

[0037] Figure 15 A schematic structural diagram of another clock synchronization device provided by an embodiment;

[0038] Figure 16 A schematic structural diagram of a base station provided in one embodiment;

[0039] Figure 17 A schematic diagram of the structure of a UE provided in one embodiment;

[0040] Figure 18 A schematic diagram of the structure of an AMF provided by an embodiment;

[0041] Figure 19A schematic structural diagram of a base station provided in one embodiment. DETAILED DESCRIPTION

[0042] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0043] Figure 1 A flowchart of a clock synchronization method provided by an embodiment is shown in FIG. Figure 1 As shown, the method provided in this embodiment includes the following steps.

[0044] Step S1010: If the source base station determines that the UE meets the handover condition, the source base station sends a handover request to the target base station, where the handover request includes information requesting a precise clock.

[0045] When a user equipment (UE), that is, a terminal, needs to switch cells due to mobility or other reasons in the currently accessed service cell, if the target cell to be switched belongs to a different base station from the current service cell, a cross-base station cell switch is involved. Since the clock information of different base stations may be different, when the UE switches cells across base stations, the clocks of the source base station and the target base station may be out of sync, causing communication problems in the target cell after the switch. The source base station is the base station to which the UE's current service cell belongs, and the target base station is the base station to which the UE's target cell belongs. In an embodiment of the present application, both the source base station and the target base station can be gNBs in the fifth generation mobile communication (5h Generation, 5G).

[0046] The clock synchronization method provided in this embodiment is applied to the source base station, that is, the base station to which the service cell belongs before the UE performs inter-cell switching. When the source base station determines that the UE accessing the cell to which the source base station belongs meets the switching conditions, it is necessary to send a switching request to the target base station to which the target cell to which the UE is switching belongs, and the switching request includes information requesting a precise clock. Since the source base station currently accessed by the UE may be different from the target base station to which the target cell to which the UE is switching belongs, when the UE meets the switching conditions, in order to synchronize the UE clock with the target cell after the switching, the source base station needs to obtain the precise clock information of the target base station. The source base station sends a switching request to the target base station, and the switching request is used to request that the UE's service cell be switched to the target cell provided by the target base station, and the switching request includes information requesting a precise clock. Among them, the precise clock information is a clock with a granularity of less than 10 milliseconds.

[0047] The UE may meet the handover condition in, for example, the case where the service quality of the neighboring cell is better than that of the current serving cell, or the received signal strength of the neighboring cell is higher than that of the current serving cell, or other situations. The source base station may determine whether the UE meets the handover condition based on the neighboring cell measurement report received from the UE.

[0048] Step S1020: The source base station receives the precise clock information of the target base station.

[0049] After the source base station sends a handover request to the target base station, it receives the target base station's precise clock information. This precise clock information represents the target base station's precise clock. The source base station and the UE can determine the clock difference between the source and target base stations based on the target base station's precise clock information and the source base station's clock information, allowing them to synchronize their clocks based on this clock difference.

[0050] There are many ways for the source base station to obtain the precise clock information of the target base station of the neighboring cell. In one embodiment, the source base station can directly send a handover request (HANDOVER REQUEST) to the target base station of the neighboring cell through the Xn interface between the base stations. The handover request includes information requesting a precise clock. After the target base station receives the handover request, the source base station will receive the first signaling sent by the target base station carrying the precise clock information of the target base station. The first signaling is a dedicated signaling for carrying precise clock information. Among them, the first signaling may include any one of the following: handover request acknowledgment (HANDOVER REQUEST ACKNOWLEDGE), retrieval UE context request (RETRIEVE UE CONTEXT REQUEST), XN-U address indication (XN-U ADDRESS INDICATION), UE context release (UE CONTEXT RELEASE).

[0051] In one embodiment, the source base station sends a handover request message (HANDOVER REQUIRED) to the Core Access and Mobility Management Function (AMF) through the NG interface, and the handover request message includes information requesting a precise clock. When the AMF receives the handover request message, it sends a handover request (HANDOVER REQUEST) to the target base station to which the neighboring cell belongs, and the handover request includes information requesting a precise clock, and receives a third signaling sent by the target base station carrying the precise clock information of the target base station. The base station will then receive a second signaling sent by the AFM carrying the precise clock information of the target base station. Both the second signaling and the third signaling are dedicated signaling for carrying precise clock information. The third signaling may include any one of the following: handover request confirmation (HANDOVER REQUESTACKNOWLEDGE), path switch request (PATH SWITCH REQUEST), and UE context release completion (UE CONTEXTRELEASE COMPLETE). The second signaling may include any one of the following: handover command (HANDOVER COMMAND), path switch request confirmation (PATH SWITCH REQUEST ACKNOWLEDGE), UE context release command (UE CONTEXTRELEASE COMMAND), downlink radio access network (Wireless Access Network, RAN) state change (DOWNLINK RAN STATUS TRANSFER), paging (PAGING), location reporting control (LOCATION REPORTING CONTROL).

[0052] The source base station calculates the clock difference between the target base station and the source base station based on the target base station's precise clock information and the source base station's clock information. This is the clock difference between the target cell and the current serving cell. This clock difference is calculated as (target base station's precise clock information minus source base station's clock information).

[0053] When the source base station sends a handover request message to the AMF, after the AMF sends a handover request message to the target base station, the target base station confirms that the UE can switch to the target cell, and the UE obtains the target base station resource access qualification. Then the target base station sends a handover request confirmation message (HANDOVER REQUEST ACKNOWLEDGE) to the AMF, and the AMF then sends a handover command message (HANDOVER COMMAND) to the source base station.

[0054] After receiving the precise clock information from the target base station, the source base station calculates the clock difference between the target base station and the source base station based on the precise clock information of the target base station and its own clock information. This time difference allows the clock of the UE that has been handed over to the target base station to be synchronized with the target base station. The source base station can notify the UE of the precise clock information of the target base station, allowing the UE to calculate the clock difference, or the source base station can calculate the clock difference and send it to the UE.

[0055] In one embodiment, the source base station may send first RRC reconfiguration information to the UE, where the first RRC reconfiguration information includes a clock difference, where the clock difference is a difference between clocks of the target base station and the source base station.

[0056] The source base station sends a first radio resource control (RRC) reconfiguration message (RRC Reconfiguration) to the UE, and the first RRC reconfiguration message includes the clock difference between the target base station and the source base station. The UE can perform delay compensation on the target cell based on the clock difference between the target base station and the source base station. When the clock difference is positive, it means that the clock of the target base station is earlier than the source base station, and the UE can send information in advance to achieve synchronization. If the clock difference is positive, it means that the clock of the target base station is later than the source base station, and the UE can delay sending information to achieve synchronization. Since the first RRC reconfiguration message sent by the source base station to the UE includes the clock difference between the target base station and the source base station, when the UE switches to the target cell provided by the target base station, it can use the same clock as the target cell to communicate in the target cell. The source base station can determine that the UE can switch to the target base station after receiving the switching request confirmation sent by the target base station. After the target base station confirms that the UE can switch to the target cell, the UE will obtain the target base station resource access qualification, and then the target base station will send a switching request confirmation to the source base station. After receiving the handover request confirmation sent by the target base station, the source base station then sends the first RRC reconfiguration information to the UE. Alternatively, the source base station may send the first RRC reconfiguration information to the UE after receiving the precise clock information of the target base station. Alternatively, the source base station may send the clock difference between the target base station and the source base station to the UE in other information.

[0057] In the clock synchronization method provided in this embodiment, if the source base station determines that the UE meets the switching conditions, the source base station sends a switching request including information requesting a precise clock to the target base station, and then the source base station receives the precise clock information of the target base station, so that the UE can achieve precise clock synchronization with the switched target base station after the cell switching.

[0058] In one embodiment, before the source base station determines that the UE meets the switching conditions, it also includes: the source base station receives the neighboring cell measurement report sent by the UE. Before performing cell switching, the UE will measure the neighboring cells of the current serving cell and report the measurement report of the neighboring cells to the base station to which the current serving cell belongs, that is, the source base station. After the source base station receives the neighboring cell measurement report, it will first determine whether the base station to which the measured neighboring cell belongs is the source base station itself. If so, since the target cell to be switched and the current serving cell of the UE are both provided by the source base station, the source base station can directly switch the cell for the UE, and there will be no problem of clock asynchrony. If the base station to which the neighboring cell measurement report sent by the UE received by the source base station corresponds is different from the source base station, then after the UE's serving cell is switched to the neighboring cell, there may be problems with the switching due to the clock asynchrony between the source base station and the base station to which the neighboring cell belongs. Therefore, when the base station to which the neighboring cell measurement report sent by the UE to the source base station corresponds is different from the source base station, the source base station will obtain precise clock information from the target base station.

[0059] The neighboring cell measurement report sent by the UE and received by the source base station may include an indication that precise clock information is required, and the source base station determines that the UE needs to perform precise clock synchronization with the target base station based on the indication that precise clock information is required. Alternatively, the source base station may receive an indication that precise clock information is required sent by the UE before receiving the neighboring cell measurement report sent by the UE. The indication information sent by the UE may be carried in one of the following ways: Radio Link Control (RLC) status packet, Media Access Control Control Element (MAC CE), Media Access Control Control Preamble (MAC Preamble), Packet Data Convergence Protocol (PDCP) status packet, RRC message. Then the neighboring cell measurement report sent by the UE does not need to include an indication that precise clock information is required, and the source base station may determine that the UE needs to perform precise clock synchronization with the target base station based on the indication that precise clock information is required sent by the UE before sending the measurement report.

[0060] Figure 2 A flowchart of a clock synchronization method provided in another embodiment is shown in FIG. Figure 2 As shown, the method provided in this embodiment includes the following steps.

[0061] Step S2010: The source base station sends a second RRC reconfiguration message to the UE, where the second RRC reconfiguration message includes a list of neighboring cells that support precise clock information indication.

[0062] In order to obtain cells that support precise clock information in a timely and accurate manner, allowing the UE to perform more targeted cell measurements, the source base station may send a second RRC reconfiguration message to the UE before receiving the neighboring cell measurement report sent by the UE. The second RRC reconfiguration message includes measurement control information, which includes a list of neighboring cells that support precise clock information indication. The UE can then perform measurement configuration based on the measurement control information. When the UE needs to synchronize its precise clock with the target cell after cell handover, the UE can perform neighboring cell measurements only on the cells in the list of neighboring cells that support precise clock information indication.

[0063] Step S2020: The source base station receives an RRC reconfiguration complete message sent by the UE. The RRC reconfiguration complete message is sent by the UE after performing measurement configuration according to the second RRC reconfiguration message.

[0064] After the UE performs measurement configuration according to the second RRC reconfiguration message sent by the source base station, the source base station will be able to receive an RRC reconfiguration complete message (RRC Reconfigration Complete) sent by the source base station. This allows UEs requiring precise clock information to measure cells that support precise clock information, thereby reducing the number of measurement targets and improving measurement performance.

[0065] Step S2030: The source base station receives a measurement report of a neighboring cell supporting precise clock information sent by the UE. The neighboring cell corresponding to the neighboring cell measurement report is a target cell for the UE handover, and the target cell belongs to a different target base station than the source base station.

[0066] After the UE receives the second RRC reconfiguration message from the source base station, since the UE has configured measurements based on the second RRC reconfiguration message, the UE can perform targeted neighbor cell measurements, measuring only those cells that support precise clock information. The source base station can then receive measurement reports from the UE for neighbor cells that support precise clock information.

[0067] The source base station can then execute steps S2040 to S2070. The source base station determines whether the UE should be switched based on the measurement report of the neighboring cell that supports precise clock information, and performs delay compensation based on the clock difference between the source base station and the target base station of the target cell to which the UE is switched during the switching process. The specific implementation of steps S2040 to S2060 is as follows: Figure 1 The illustrated embodiment has been described in detail and will not be repeated here.

[0068] Step S2040: If the source base station determines that the UE meets the handover condition, the source base station sends a handover request to the target base station, where the handover request includes information requesting a precise clock.

[0069] Step S2050: The source base station receives the precise clock information of the target base station.

[0070] Step S2060: After receiving the handover request confirmation sent by the target base station, the source base station sends first RRC reconfiguration information to the UE. The first RRC reconfiguration information includes a clock difference, which is the difference between the clocks of the target base station and the source base station.

[0071] The clock synchronization method provided in this embodiment Figure 1 On the basis of the illustrated embodiment, since the source base station first receives the neighboring cell report sent by the UE, and the source base station sends a second RRC reconfiguration message including a list of neighboring cells supporting precise clock information to the UE, so that the UE can perform measurement configuration according to the second RRC reconfiguration message, the source base station can only receive the measurement report of the neighboring cell supporting precise clock information sent by the UE, so that the UE with precise clock information requirements can measure the cell supporting precise clock information, thereby reducing the measurement objects and improving the measurement performance.

[0072] In one embodiment, Figure 1 or Figure 2 Based on the illustrated embodiment, if a radio link failure (RLF) occurs in a UE, in order to enable the UE to obtain precise clock information about the target base station in a timely and accurate manner, the UE's source base station may further broadcast system information block (SIB) information, where the SIB information includes a list of neighboring cells that support precise clock information indication. The SIB information is used to enable the UE to select a target cell from the list of neighboring cells that support precise clock information indication when a radio link failure occurs, thereby completing RRC reestablishment. The SIB information broadcast by the source base station may be SIB3 or SIB4 information, where the parameters in the SIB3 or SIB4 information are for the current serving cell. After the UE receives the SIB information broadcast by the UE including the list of neighboring cells that support precise clock information, it may perform cell selection for the cell that supports precise clock information. When the UE selects a suitable cell, it sends an RRC Reestablishment Request message to the target base station to which the selected target cell belongs, where the message includes information requesting precise clock information. Upon receipt of the RRC Reestablishment Request by the target base station, the target base station sends an RRC Reestablishment message carrying precise clock information to the UE. After the UE receives the precise clock information, it sends an RRC Reestablishment Complete message to the target base station. The message does not carry any actual information and only serves as an RRC layer confirmation.

[0073] In one embodiment, Figure 1 or Figure 2 On the basis of the illustrated embodiment, if a radio link failure occurs in the UE, in order to enable the UE to obtain precise clock information about the target base station in a timely and accurate manner, the source base station of the UE may further broadcast SIB information, where the SIB information includes a list of neighboring cells containing precise clock information of neighboring cells. The SIB information is used to enable the UE to select a target cell from a list of neighboring cells containing precise clock information of neighboring cells when the radio link fails, and complete RRC reestablishment. The SIB information broadcast by the source base station may be SIB3 or SIB4 information, and the parameters in the SIB3 or SIB4 information are for the current serving cell. After the UE receives the SIB information broadcast by the UE including the list of neighboring cells containing precise clock information of neighboring cells, it may perform cell selection for cells that support precise clock information. When the UE selects a suitable cell, the UE will send an RRC Reestablishment Request message to the target base station to which the selected target cell belongs. Based on the target base station receiving the RRC Reestablishment Request, the target base station sends an RRC Reestablishment to the UE. After the UE receives the RRC re-establishment signal, it uses the neighbor cell list containing the precise clock information of the neighboring cells to read the precise clock information of the target base station. Based on the UE's clock information, it calculates the synchronization clock difference and sends an RRC Re-establishment Complete signal to the target gNB. This signal carries no actual information and serves only as an RRC layer confirmation. The neighbor cell list containing the precise clock information of the neighboring cells contains the precise clock information of the target base station. For example, the precise clock information of the cell is included in the intra-frequency cell reselection information related to the neighboring cell in SIB3; the precise clock information of the cell is included in the inter-frequency cell reselection information related to the neighboring cell in SIB4. After receiving the RRC re-establishment signal, the UE uses the difference between the precise clock information of the new cell in the neighbor cell list and the UE's clock information as the synchronization clock difference, i.e., the lead value that the UE needs to send.

[0074] Figure 3 A flowchart of another clock synchronization method provided by an embodiment, such as Figure 3 As shown, the method provided in this embodiment includes the following steps.

[0075] Step S3010: The UE receives first RRC reconfiguration information sent by the source base station. The first RRC reconfiguration information includes a clock difference, which is the difference between the clocks of the target base station and the source base station.

[0076] The clock synchronization method provided in this embodiment is applied to UE. When the UE needs to perform cell switching in the currently accessed serving cell due to mobility or other reasons, if the target cell to be switched belongs to a different base station from the current serving cell, it involves cell switching across base stations. Since the clock information of different base stations may be different, when the UE performs cell switching across base stations, the clocks of the source base station and the target base station may be out of sync, causing communication problems in the target cell after the UE is switched. The source base station is the base station to which the UE's current serving cell belongs, and the target base station is the base station to which the UE's switching target cell belongs. In this embodiment of the present application, both the source base station and the target base station can be gNBs in 5G.

[0077] When the source base station determines that the UE accessing the cell to which the source base station belongs meets the handover conditions, it needs to send a handover request to the target base station to which the target cell to which the UE is handing over belongs. The handover request includes information requesting a precise clock. Since the source base station currently accessed by the UE may be different from the target base station to which the target cell to which the UE is handing over belongs, when the UE meets the handover conditions, in order to synchronize the UE's clock with the target cell after handover, the source base station needs to obtain the precise clock information of the target base station. The source base station sends a handover request to the target base station. The handover request is used to request that the UE's serving cell be switched to the target cell provided by the target base station. The handover request includes information requesting a precise clock. Among them, the precise clock information is a clock with a granularity of less than 10 milliseconds.

[0078] After the source base station sends a handover request to the target base station, it receives the target base station's precise clock information. This precise clock information represents the target base station's precise clock. The source base station and the UE can determine the clock difference between the source and target base stations based on the target base station's precise clock information and the source base station's clock information, allowing them to synchronize their clocks based on this clock difference.

[0079] After determining the clock difference between the target base station and the source base station, if the source base station receives a handover request confirmation from the target base station and determines that the UE can be handed over to the target base station, and the target base station confirms that the UE can be handed over to the target cell, the UE will obtain target base station resource access qualifications, and then the target base station will send a handover request confirmation to the source base station. The source base station will send first RRC reconfiguration information to the UE, and the first RRC reconfiguration information will include the clock difference between the target base station and the source base station.

[0080] After the UE receives the first RRC reconfiguration information, it can compensate for the delay of the target cell based on the clock difference between the target base station and the source base station. When the clock difference is positive, it means that the clock of the target base station is earlier than that of the source base station, and the UE can send information in advance to achieve synchronization. If the clock difference is positive, it means that the clock of the target base station is later than that of the source base station, and the UE can delay sending information to achieve synchronization. Since the first RRC reconfiguration information sent by the source base station to the UE includes the clock difference between the target base station and the source base station, when the UE switches to the target cell provided by the target base station, it can use the same clock as the target cell to communicate in the target cell.

[0081] In the clock synchronization method provided in this embodiment, the UE receives the first RRC reconfiguration information sent by the source base station, which includes the clock difference between the target base station and the source base station. Then, the UE can compensate for the delay of the target cell according to the clock difference, so that the UE can achieve accurate clock synchronization with the switched target base station after the cell is switched.

[0082] In one embodiment, before the UE receives the first RRC reconfiguration information sent by the source base station, it also includes: the UE sends a neighboring cell measurement report to the source base station. Before performing cell switching, the UE will measure the neighboring cells of the current serving cell and report the measurement report of the neighboring cells to the base station to which the current serving cell belongs, that is, the source base station. After the source base station receives the neighboring cell measurement report, it will first determine whether the base station to which the measured neighboring cell belongs is the source base station itself. If so, since the target cell to be switched and the current serving cell of the UE are both provided by the source base station, the source base station can directly switch the cell for the UE, and there will be no problem of clock asynchrony. If the neighboring cell measurement report sent by the UE received by the source base station corresponds to a base station different from the source base station, then after the UE's serving cell is switched to the neighboring cell, there may be problems with the switching due to the clock asynchrony between the source base station and the base station to which the neighboring cell belongs. Therefore, when the base station to which the neighboring cell measurement report sent by the UE to the source base station corresponds to is different from the source base station, the source base station will obtain the net clock information from the target base station.

[0083] The neighboring cell measurement report sent by the UE may include an indication that precise clock information is required, and the source base station determines that the UE needs to perform precise clock synchronization with the target base station based on the indication that precise clock information is required. Alternatively, if the UE sends an indication that precise clock information is required to the source base station before sending the neighboring cell measurement report to the source base station, then the neighboring cell measurement report sent by the UE does not need to include an indication that precise clock information is required, and the source base station may determine that the UE needs to perform precise clock synchronization with the target base station based on the indication that precise clock information is required sent by the UE before sending the measurement report.

[0084] After the source base station receives the neighboring cell measurement report sent by the UE, it can determine whether the UE meets the switching conditions based on the neighboring cell measurement report. The situation in which the UE meets the switching conditions may be, for example, that the service quality of the neighboring cell is better than that of the current serving cell, or the received signal strength of the neighboring cell is higher than that of the current serving cell, or other situations. After the source base station receives the neighboring cell measurement report sent by the UE, it is known to those skilled in the art that the source base station determines whether the UE meets the switching conditions, which will not be repeated here. When the base station to which the neighboring cell corresponding to the neighboring cell measurement report received by the source base station belongs is different from the source base station, if the UE meets the switching conditions, in order to synchronize the clock of the UE with the target cell after switching, the source base station needs to obtain the precise clock information of the target base station to which the neighboring cell belongs. The source base station sends a switching request to the target base station to which the neighboring cell belongs. The switching request is used to request that the UE's serving cell be switched to the neighboring cell corresponding to the neighboring cell measurement report. The switching request includes information requesting a precise clock. After sending the switching request to the target base station, the source base station will receive the precise clock information of the target base station. The precise clock information of the target base station represents the precise clock of the target base station. The source base station and the UE can determine the clock difference between the source base station and the target base station based on the precise clock information of the target base station and the clock information of the source base station, thereby performing clock synchronization based on the clock difference.

[0085] Figure 4 A flowchart of another clock synchronization method provided by an embodiment, such as Figure 4 As shown, the method provided in this embodiment includes the following steps.

[0086] Step S4010: The UE receives a second RRC reconfiguration message sent by the source base station, where the second RRC reconfiguration message includes a list of neighboring cells that support precise clock information indication.

[0087] In order to obtain cells that support precise clock information in a timely and accurate manner, allowing the UE to perform more targeted cell measurements, the UE can receive a second RRC reconfiguration message from the source base station before sending a neighbor cell measurement report to the source base station. The second RRC reconfiguration message includes measurement control information, which includes a list of neighbor cells that support precise clock information indication. The UE can then perform measurement configuration based on the measurement control information. When the UE needs to synchronize its precise clock with the target cell after cell handover, the UE can perform neighbor cell measurements only on the cells in the list of neighbor cells that support precise clock information indication.

[0088] Step S4020: The UE performs measurement configuration according to the second RRC reconfiguration message, and sends an RRC reconfiguration complete message to the source base station.

[0089] After the UE performs measurement configuration according to the second RRC reconfiguration message sent by the source base station, the source base station will be able to receive an RRC reconfiguration complete message (RRC Reconfigration Complete) sent by the source base station. This allows UEs requiring precise clock information to measure cells that support precise clock information, thereby reducing the number of measurement targets and improving measurement performance. The UE then sends an RRC reconfiguration complete message to the source base station.

[0090] In step S4030, the UE measures the cells in the neighboring cell list that support precise clock information indication, and sends a measurement report of the neighboring cells that support precise clock information to the source base station. The neighboring cell corresponding to the neighboring cell measurement report is the target cell to which the UE switches. The target base station to which the target cell belongs is different from the source base station. The neighboring cell measurement report is used to enable the source base station to obtain the precise clock information of the target base station.

[0091] After receiving the second RRC reconfiguration message from the source base station, the UE measures the cells in the list of neighboring cells that support precise clock information according to the second RRC reconfiguration message. Because the UE has configured measurements according to the second RRC reconfiguration message, it can perform targeted neighbor cell measurements, measuring only cells that support precise clock information. The UE can then send measurement reports for neighboring cells that support precise clock information to the source base station.

[0092] The source base station can then execute steps S4040-S4050. The source base station determines whether the UE needs to be switched based on the measurement report of the neighboring cell that supports precise clock information, and performs delay compensation during the switching process based on the clock difference between the source base station and the target base station to which the UE switches.

[0093] Step S4040: The UE receives first RRC reconfiguration information sent by the source base station. The first RRC reconfiguration information includes a clock difference, which is a difference between the clocks of the target base station and the source base station.

[0094] Step S4050: The UE performs delay compensation on the target cell according to the clock difference.

[0095] The clock synchronization method provided in this embodiment is Figure 3 On the basis of the illustrated embodiment, since before the UE sends a neighbor cell report to the source base station, it first receives a second RRC reconfiguration message sent by the source base station including a list of neighbor cells supporting precise clock information, so that the UE can perform measurement configuration according to the second RRC reconfiguration message, the UE can send a measurement report of the neighbor cells supporting precise clock information to the source base station, so that the UE with precise clock information requirements can measure the cells supporting precise clock information, thereby reducing the measurement objects and improving the measurement performance.

[0096] In one embodiment, Figure 3 or Figure 4 Based on the illustrated embodiment, if a radio link failure occurs in the UE, in order to enable the UE to obtain precise clock information about the target base station in a timely and accurate manner, the UE may also receive SIB information broadcast by the source base station, where the SIB information includes a list of neighboring cells that support precise clock information indication. The SIB information is used to enable the UE to select a target cell from the list of neighboring cells that support precise clock information indication when the radio link fails, and complete RRC reestablishment. The SIB information broadcast by the source base station may be SIB3 or SIB4 information, and the parameters in the SIB3 or SIB4 information are for the current serving cell. After the UE receives the SIB information broadcast by the UE including the list of neighboring cells that support precise clock information indication, it may perform cell selection for cells that support precise clock information. When the UE selects a suitable cell, the UE will send an RRC Reestablishment Request message to the target base station to which the selected target cell belongs, where the message includes information requesting precise clock. Based on the target base station receiving the RRC Reestablishment Request, the target base station will send an RRC Reestablishment message carrying precise clock information to the UE. After the UE receives the precise clock information, it sends an RRC Reestablishment Complete message to the target base station. The message does not carry any actual information and only serves as an RRC layer confirmation.

[0097] In one embodiment, Figure 3 or Figure 4On the basis of the illustrated embodiment, if a radio link failure occurs in the UE, in order to enable the UE to obtain the precise clock information about the target base station in a timely and accurate manner, the UE may also receive the broadcast SIB information sent by the source base station, where the SIB information includes a neighboring cell list containing the precise clock information of the neighboring cells. The SIB information is used to enable the UE to select the target cell from the neighboring cell list containing the precise clock information of the neighboring cells when the radio link fails, and complete the RRC reestablishment. The SIB information broadcast by the source base station may be SIB3 or SIB4 information, and the parameters in the SIB3 or SIB4 information are for the current serving cell. After the UE receives the SIB information broadcast by the UE including the neighboring cell list containing the precise clock information of the neighboring cells, it may perform cell selection for the cell that supports the precise clock information. When the UE selects a suitable cell, the UE will send an RRC Reestablishment Request message to the target base station to which the selected target cell belongs. Based on the target base station receiving the RRC Reestablishment Request, the target base station sends an RRC Reestablishment to the UE. After the UE receives the RRC re-establishment signal, it uses the neighbor cell list containing the precise clock information of the neighboring cells to read the precise clock information of the target base station. Based on the UE's clock information, it calculates the synchronization clock difference and sends an RRC Re-establishment Complete signal to the target gNB. This signal carries no actual information and serves only as an RRC layer confirmation. The neighbor cell list containing the precise clock information of the neighboring cells contains the precise clock information of the target base station. For example, the precise clock information of the cell is included in the intra-frequency cell reselection information related to the neighboring cell in SIB3; the precise clock information of the cell is included in the inter-frequency cell reselection information related to the neighboring cell in SIB4. After receiving the RRC re-establishment signal, the UE uses the difference between the precise clock information of the new cell in the neighbor cell list and the UE's clock information as the synchronization clock difference, i.e., the lead value that the UE needs to send.

[0098] Figure 5 A flowchart of a clock synchronization method provided by an embodiment is shown in FIG. Figure 5 As shown, the method provided in this embodiment includes the following steps.

[0099] Step S5010: The AMF receives a switching request message including information requesting a precise clock from the source base station.

[0100] Step S5020: The AMF sends a handover request including information requesting a precise clock to the target base station.

[0101] Step S5030: The AMF receives the second signaling sent by the target base station, which carries the precise clock information of the target base station.

[0102] Step S5040: The AMF sends a third signaling carrying the precise clock information of the target base station to the source base station.

[0103] The clock synchronization method provided in this embodiment is applied to AFM, wherein the source base station sends a handover request message (HANDOVER REQUIRED) to the AMF through the NG interface, and the handover request message includes information requesting a precise clock. When the AMF receives the handover request message, it sends a handover request (HANDOVER REQUEST) to the target base station to which the neighboring cell belongs, wherein the handover request includes information requesting a precise clock, and receives a third signaling sent by the target base station carrying the precise clock information of the target base station. Subsequently, the base station will receive a second signaling sent by the AFM carrying the precise clock information of the target base station. Both the second signaling and the third signaling are dedicated signaling for carrying precise clock information. The third signaling may include any one of the following: handover request acknowledgment (HANDOVER REQUEST ACKNOWLEDGE), path switch request (PATH SWITCH REQUEST), and UE context release completion (UE CONTEXT RELEASE COMPLETE). The second signaling may include any one of the following: handover command (HANDOVER COMMAND), path switch request confirmation (PATH SWITCH REQUEST ACKNOWLEDGE), UE context release command (UE CONTEXT RELEASE COMMAND), downlink radio access network (Wireless Access Network, RAN) state change (DOWNLINK RAN STATUS TRANSFER), paging (PAGING), location reporting control (LOCATION REPORTING CONTROL).

[0104] Figure 6 A flowchart of a clock synchronization method provided by an embodiment is shown in FIG. Figure 6 As shown, the method provided in this embodiment includes the following steps.

[0105] Step S6010: The target base station receives a switching request message including a request for precise clock information sent by the source base station, a switching request message including a request for precise clock information sent by the AMF, or an RRC reconstruction request message including a request for precise clock information sent by the UE.

[0106] Step S6020: The target base station sends the precise clock information to the source base station through the first signaling, sends the precise clock information to the AMF through the third signaling, or sends the precise clock information to the UE through the RRC response message.

[0107] The clock synchronization method provided in this embodiment is applied to the target base station. Regardless of whether the target base station receives a switching request message including a request for precise clock information sent by the source base station, or a switching request message including a request for precise clock information sent by the AMF, or receives an RRC reconstruction request message including a request for precise clock information sent by the UE, it can be known that the source base station or the UE needs to know the precise clock information of the target base station. Then the target base station can send the precise clock information to the source base station through the first signaling, or send the precise clock information to the AMF through the third signaling, or send the precise clock information to the UE through the RRC response message. The processing performed by the source base station or UE after receiving the precise clock information has been described in detail in the aforementioned embodiment and will not be repeated here. Among them, the first signaling includes any one of the following: switching request confirmation, UE context retrieval request, XN-U address indication, UE context release.

[0108] Figure 7 An interactive flow chart of a clock synchronization method provided in an embodiment, such as Figure 7 As shown, the method provided in this embodiment includes the following steps.

[0109] Step 1: The UE measures neighboring cells and reports the precise clock information requirement to the source gNB in the measurement results. Alternatively, the measurement report does not include the precise clock information requirement but the source gNB can obtain the precise clock information requirement based on the precise clock request made by the UE before the measurement. The source gNB then determines whether the handover conditions are met.

[0110] Step 2: The source gNB sends a HANDOVER REQUEST message to the target gNB, which includes the precise clock request information.

[0111] Step 3: After receiving the Handover Request message from the source gNB, the target gNB sends dedicated signaling with precise clock information to the source gNB.

[0112] Step 4: After obtaining the target gNB resource admission qualification, the target gNB sends a handover request confirmation message to the source gNB.

[0113] Step 5: Based on the target gNB's precise clock information in dedicated signaling, the clock difference between the new and old cells is calculated based on the source gNB's clock information (target gNB clock minus source gNB clock). The source gNB then sends an "RRC Reconfiguration" message to the UE, which includes the clock difference between the new and old cells. The UE synchronizes by sending an early signal if the clock difference between the new and old cells is positive, or by delaying the signal if it is negative.

[0114] Based on the precise clock information request from the source gNB, the target gNB sends dedicated signaling carrying the precise clock information. The dedicated signaling includes at least one of the following: HANDOVER REQUEST ACKNOWLEDGE, RETRIEVE UE CONTEXT REQUEST, XN-U ADDRESS INDICATION, or UE CONTEXT RELEASE.

[0115] This embodiment is an inter-base station handover based on the Xn port. In order to obtain precise clock information about the target base station in a timely and accurate manner, the source base station receives dedicated signaling containing precise clock information from the target base station. Based on this information and the local clock information of the source base station, the clock difference between the new and old cells is obtained. The UE uses this clock difference to compensate for the delay of the target cell.

[0116] Figure 8 This is an interactive flow chart of another clock synchronization method provided by an embodiment, such as Figure 8 As shown, the method provided in this embodiment includes the following steps.

[0117] Step 1: The UE measures neighboring cells and reports the precise clock information requirement to the source gNB in the measurement results. Alternatively, the measurement report does not include the precise clock information requirement but the source gNB can obtain the precise clock information requirement based on the precise clock request made by the UE before the measurement. The source gNB then determines whether the handover conditions are met.

[0118] Step 2: The source gNB sends a HANDOVER REQUIRED message to the AMF, which includes the precise clock request information.

[0119] Step 3: The AMF sends a HANDOVER REQUEST message to the target gNB, which includes the request for precise clock information.

[0120] Step 4: After receiving the AMF Handover Request message, the target gNB sends dedicated signaling carrying precise clock information to the AMF.

[0121] Step 5: After receiving the Handover Request message from the target gNB, the AMF sends dedicated signaling with precise clock information to the source gNB.

[0122] Step 6: After obtaining the target gNB resource admission qualification, the target gNB sends a HANDOVER REQUEST ACKNOWLEDGE message to the AMF.

[0123] Step 7: The AMF sends a HANDOVER COMMAND message to the source gNB.

[0124] Step 8: Based on the target gNB's precise clock information in dedicated signaling, the clock difference between the new and old cells is calculated based on the source gNB's clock information (target gNB clock minus source gNB clock). The source gNB then sends an "RRC Reconfiguration" message to the UE, which includes the clock difference between the new and old cells. The UE synchronizes by sending an early signal if the clock difference between the new and old cells is positive, or by delaying the signal if it is negative.

[0125] Based on the precise clock information request from the AMF, the target gNB sends dedicated signaling carrying the precise clock information. The dedicated signaling includes at least one of the following: HANDOVER REQUEST ACKNOWLEDGE, PATH SWITCH REQUEST, UE CONTEXT RELEASE COMPLETE, UE CONTEXT RELEASE, PAGING, or LOCATION REPORT.

[0126] Based on the precise clock information request of the source gNB, the AMF sends dedicated signaling carrying the precise clock information. The dedicated signaling includes at least one of the following methods: handover command (HANDOVER COMMAND), path switch request confirmation (PATHSWITCH REQUEST ACKNOWLEDGE), UE message release command (UE CONTEXT RELEASE COMMAND), downlink RAN status change (DOWNLINK RAN STATUS TRANSFER), paging (PAGING), location reporting control (LOCATION REPORTING CONTROL).

[0127] In this embodiment, in order to obtain the precise clock information of the target base station in a timely and accurate manner, the inter-base station switching based on the NG port receives the dedicated signaling of the AMF containing the precise clock information of the target base station through the source base station; based on this information and the local clock information of the source base station, the clock difference between the new and old cells is obtained; the UE compensates the target cell for delay through this clock difference.

[0128] Figure 9 This is an interactive flow chart of another clock synchronization method provided by an embodiment, such as Figure 9 As shown, the method provided in this embodiment includes the following steps.

[0129] Step 1: Based on the precise clock request before the measurement, the source gNB sends a measurement control to the UE and configures the UE's measurement type through an RRC Reconfiguration message. The configuration includes a list of neighbor cells that support precise clock information indication.

[0130] Step 2: The UE performs measurement configuration on the RRC protocol side according to the measurement control issued by the source gNB, and sends an RRC Reconfiguration Complete message to the source gNB to indicate that the measurement configuration is complete.

[0131] Step 3: During the measurement phase, the RRC reconfiguration includes a list of neighbor cells that support precise clock information, so that UEs with precise clock information requirements can measure cells that support precise clock information. The UE reports measurement reports to the source gNB that only include cells that support precise clock information according to the measurement configuration.

[0132] Based on the measurement report, the gNB determines whether the UE should be handed over and grants resource admission to the new cell. After successful resource admission, the gNB applies for new air interface resources for the UE. During the handover process, the gNB uses the clock difference between the new and old cells to achieve delay compensation.

[0133] In this embodiment, based on the precise clock request before the measurement, in triggering the measurement and reporting, in order to timely and accurately obtain the cells that support precise clock information, the neighboring cell list that supports precise clock information indication is included in the RRC reconfiguration during the measurement phase. This allows the UE with precise clock information requirements to measure the cells that support precise clock information, thereby reducing the number of measurement objects and improving measurement performance.

[0134] Figure 10 This is an interactive flow chart of another clock synchronization method provided by an embodiment, such as Figure 10 As shown, the method provided in this embodiment includes the following steps.

[0135] Step 1: In the event of a radio link failure, the UE receives the SIB3 and SIB4 information broadcast by the source gNB. The SIB3 and SIB4 contain a list of neighbor cells indicating whether the cell supports precise clock information.

[0136] Step 2: After the UE obtains the neighboring cell list containing the precise clock information, it performs a cell selection procedure for the cells that support the precise clock information.

[0137] Step 3: After selecting a suitable cell, the UE sends an RRC Reestablishment Request message to the target gNB, which contains information requesting a precise clock.

[0138] Step 4: Upon receiving the RRC Reestablishment Request, the target gNB sends an RRC Reestablishment message with the precise clock information to the UE.

[0139] Step 5: After the UE receives the precise clock information, it sends an RRC Reestablishment Complete message to the target gNB. This message does not carry any actual information and only serves as an RRC layer confirmation.

[0140] In this embodiment, in the event of a radio link failure, in order to obtain precise clock information about the target base station in a timely and accurate manner, the source base station broadcasts an indication of whether the neighboring cell list in the SIB3 and SIB4 information supports precise clock information, selects cells that support precise clock information, and sends precise clock information to the target gNB during the RRC re-establishment process.

[0141] Figure 11 This is an interactive flow chart of another clock synchronization method provided by an embodiment, such as Figure 11 As shown, the method provided in this embodiment includes the following steps.

[0142] Step 1: In the event of a radio link failure, the UE receives the SIB3 and SIB4 information broadcast by the source gNB. The neighbor list in the SIB3 and SIB4 information contains the precise clock information of each cell.

[0143] Step 2: After the UE obtains the neighbor cell list containing the precise clock information, it performs a cell selection procedure for cells that support precise clock information.

[0144] Step 3: After selecting a suitable cell, the UE sends an RRC Reestablishment Request message to the target gNB.

[0145] Step 4: Upon receiving the RRC Reestablishment Request, the target gNB sends an RRC Reestablishment Request to the UE.

[0146] Step 5: After receiving the precise clock information, the UE uses the neighbor cell list containing the precise clock information to read the precise clock information of the target gNB. The UE calculates the synchronization clock difference based on the UE's clock information and sends an RRC Reestablishment Complete message to the target gNB. This message does not carry any actual information and serves only as an RRC layer confirmation. The neighbor cell list contains the precise clock information of the target gNB. For example, the precise clock information of the cell is contained in the intra-frequency cell reselection information related to the neighbor cell in SIB3; the precise clock information of the cell is contained in the inter-frequency cell reselection information related to the neighbor cell in SIB4.

[0147] After receiving the RRC re-establishment, the UE uses the difference between the precise clock information of the new cell in the neighbor cell list and the UE's clock information as the synchronization clock difference, that is, the advance amount that the UE needs to send at the moment.

[0148] In this embodiment, in the event of a wireless link failure, in order to obtain precise clock information about the target base station in a timely and accurate manner, the source base station broadcasts the precise clock information of each cell in the neighboring cell list in the SIB3 and SIB4 information, performs cell selection for cells that support precise clock information, and performs delay compensation based on the precise clock information of the cell in the SIB information during the RRC re-establishment process.

[0149] Figure 12 FIG. 1 is a schematic diagram of a clock synchronization device according to an embodiment of the present invention. The clock synchronization device according to this embodiment is provided in a source base station. Figure 12 As shown, the clock synchronization device provided in this embodiment includes: a sending module 121, which is configured so that if the source base station determines that the UE meets the switching conditions, the source base station sends a switching request to the target base station, and the switching request includes information requesting a precise clock; a receiving module 122, which is configured so that the source base station receives the precise clock information of the target base station.

[0150] Figure 13 FIG. 1 is a structural diagram of another clock synchronization device provided in an embodiment. The clock synchronization device provided in this embodiment is set in a UE, such as Figure 13 As shown, the clock synchronization device provided in this embodiment includes: a receiving module 131, which is configured to receive the first RRC reconfiguration information sent by the source base station, and the first RRC reconfiguration information includes a clock difference, which is the difference between the clocks of the target base station and the source base station.

[0151] Figure 14 FIG. 1 is a structural diagram of another clock synchronization device provided in an embodiment. The clock synchronization device provided in this embodiment is provided in the AMF. Figure 14As shown, the clock synchronization device provided by this embodiment includes: a receiving module 141, which is configured to receive a switching request message including information requesting a precise clock sent by a source base station; a sending module 142, which is configured to send a switching request including information requesting a precise clock to a target base station; the receiving module 141 is also configured to receive a second signaling carrying the precise clock information of the target base station sent by the target base station; the sending module 142 is also configured to send a third signaling carrying the precise clock information of the target base station to the source base station.

[0152] Figure 15 FIG. 1 is a structural diagram of another clock synchronization device provided by an embodiment. The clock synchronization device provided by this embodiment is arranged in a target base station, such as Figure 15 As shown, the clock synchronization device provided by this embodiment includes: a receiving module 151, which is configured to receive a switching request message including a request for precise clock information sent by a source base station, or a switching request message including a request for precise clock information sent by an AMF, or a radio resource control RRC reconstruction request message including a request for precise clock information sent by a user equipment UE; a sending module 152, which is configured to send the precise clock information to the source base station through a first signaling by the target base station, or send the precise clock information to the AMF through a third signaling, or send the precise clock information to the UE through an RRC response message.

[0153] Figure 16 A schematic diagram of the structure of a base station provided in an embodiment is shown in FIG. Figure 16 As shown, the base station includes a processor 161, a memory 162, a transmitter 163 and a receiver 164; the number of processors 161 in the base station can be one or more. Figure 16 In the example, a processor 161 is used; the processor 161 and the memory 162 in the base station can be connected by a bus or other means. Figure 16 The bus connection is taken as an example.

[0154] The memory 162 is a computer-readable storage medium that can be configured to store software programs, computer executable programs, and modules, such as the present application. Figure 1 or Figure 2 The program instructions / modules corresponding to the clock synchronization method in the embodiment (such as the sending module 121 and the receiving module 122) are implemented by the processor 161 by running the software programs, instructions, and modules stored in the memory 162, thereby performing at least one functional application and data processing of the base station, that is, implementing the above-mentioned clock synchronization method.

[0155] The memory 162 may primarily include a program storage area and a data storage area. The program storage area may store an operating system and at least one application required for a function; the data storage area may store data generated based on the use of the base station. Furthermore, the memory 162 may include high-speed random access memory and non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device.

[0156] The transmitter 163 is a module or device combination capable of transmitting radio frequency signals into space, such as a combination of a radio frequency transmitter, an antenna, and other devices. The receiver 164 is a module or device combination capable of receiving radio frequency signals from space, such as a combination of a radio frequency receiver, an antenna, and other devices.

[0157] Figure 17 A schematic diagram of the structure of a UE provided in an embodiment is shown in FIG. Figure 17 As shown, the UE includes a processor 171, a memory 172, a transmitter 173, and a receiver 174; the number of processors 171 in the UE may be one or more. Figure 17 In the example, a processor 171 is used; the processor 171 and the memory 172 in the UE can be connected by a bus or other means. Figure 17 The bus connection is taken as an example.

[0158] The memory 172 is a computer-readable storage medium that can be configured to store software programs, computer executable programs, and modules, such as the present application. Figure 3 or Figure 4 The clock synchronization method in the embodiment corresponds to program instructions / modules (such as the receiving module 131). The processor 171 executes the software programs, instructions, and modules stored in the memory 172, thereby performing at least one functional application and data processing of the UE, that is, implementing the above-mentioned clock synchronization method.

[0159] The memory 172 may primarily include a program storage area and a data storage area. The program storage area may store an operating system and at least one application required for a function; the data storage area may store data created based on the use of the UE. Furthermore, the memory 172 may include high-speed random access memory and non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device.

[0160] The transmitter 173 is a module or device combination capable of transmitting radio frequency signals into space, such as a combination of a radio frequency transmitter, an antenna, and other devices. The receiver 174 is a module or device combination capable of receiving radio frequency signals from space, such as a combination of a radio frequency receiver, an antenna, and other devices.

[0161] Figure 18 A schematic diagram of the structure of an AMF provided in an embodiment is shown as follows: Figure 18 As shown, the AMF includes a processor 181, a memory 182, a transmitter 183 and a receiver 184; the number of processors 181 in the AMF can be one or more. Figure 18 In the example, a processor 181 is used; the processor 181 and the memory 182 in the AMF can be connected by a bus or other means. Figure 18 The bus connection is taken as an example.

[0162] The memory 182 is a computer-readable storage medium that can be configured to store software programs, computer executable programs, and modules, such as the present application. Figure 5 The program instructions / modules corresponding to the clock synchronization method in the embodiment (such as the receiving module 141 and the sending module 142). The processor 181 executes the software programs, instructions, and modules stored in the memory 182, thereby implementing at least one functional application and data processing of the AMF, that is, implementing the above-mentioned clock synchronization method.

[0163] The memory 182 may primarily include a program storage area and a data storage area. The program storage area may store an operating system and at least one application required for a function; the data storage area may store data created based on the use of the UE. Furthermore, the memory 182 may include high-speed random access memory and non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device.

[0164] The transmitter 183 is a module or device combination capable of transmitting radio frequency signals into space, such as a combination of a radio frequency transmitter, an antenna, and other devices. The receiver 184 is a module or device combination capable of receiving radio frequency signals from space, such as a combination of a radio frequency receiver, an antenna, and other devices.

[0165] Figure 19 A schematic diagram of the structure of a base station provided in an embodiment is shown in FIG. Figure 19 As shown, the base station includes a processor 191, a memory 192, a transmitter 193 and a receiver 194; the number of processors 191 in the base station can be one or more. Figure 19 In the example, a processor 191 is used; the processor 191 and the memory 192 in the base station can be connected by a bus or other means. Figure 19 The bus connection is taken as an example.

[0166] The memory 192 is a computer-readable storage medium that can be configured to store software programs, computer executable programs, and modules, such as the present application. Figure 6The program instructions / modules (such as the receiving module 151 and the sending module 152) corresponding to the clock synchronization method in the embodiment. The processor 191 executes the software programs, instructions, and modules stored in the memory 192, thereby performing at least one functional application and data processing of the base station, that is, implementing the above-mentioned clock synchronization method.

[0167] The memory 192 may primarily include a program storage area and a data storage area. The program storage area may store an operating system and at least one application required for a function; the data storage area may store data generated based on the use of the base station. Furthermore, the memory 192 may include high-speed random access memory and non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state memory device.

[0168] The transmitter 193 is a module or device combination capable of transmitting radio frequency signals into space, such as a combination of a radio frequency transmitter, an antenna, and other devices. The receiver 194 is a module or device combination capable of receiving radio frequency signals from space, such as a combination of a radio frequency receiver, an antenna, and other devices.

[0169] An embodiment of the present application also provides a storage medium containing computer-executable instructions, which, when executed by a computer processor, are used to execute a clock synchronization method, the method comprising: if a source base station determines that the UE meets the switching conditions, the source base station sends a switching request to a target base station, the switching request including information requesting a precise clock; the source base station receives the precise clock information of the target base station.

[0170] An embodiment of the present application also provides a storage medium containing computer-executable instructions, which, when executed by a computer processor, are used to perform a clock synchronization method, the method comprising: a UE receives first RRC reconfiguration information sent by a source base station, the first RRC reconfiguration information including a clock difference, and the clock difference is the difference between the clocks of the target base station and the source base station.

[0171] An embodiment of the present application also provides a storage medium containing computer-executable instructions, which, when executed by a computer processor, are used to execute a clock synchronization method, the method comprising: AMF receiving a switching request message including information requesting a precise clock sent by a source base station; AMF sending a switching request including information requesting a precise clock to a target base station; AMF receiving a second signaling carrying the precise clock information of the target base station sent by the target base station; and AMF sending a third signaling carrying the precise clock information of the target base station to the source base station.

[0172] An embodiment of the present application also provides a storage medium containing computer-executable instructions, which, when executed by a computer processor, are used to perform a clock synchronization method, the method comprising: a target base station receives a switching request message including a request for precise clock information sent by a source base station, or a switching request message including a request for precise clock information sent by an AMF, or an RRC reconstruction request message including a request for precise clock information sent by a UE; the target base station sends the precise clock information to the source base station through a first signaling, or sends the precise clock information to the AMF through a third signaling, or sends the precise clock information to the UE through an RRC response message.

[0173] The above are merely exemplary embodiments of the present application and are not intended to limit the scope of protection of the present application.

[0174] It will be appreciated by those skilled in the art that the term user terminal covers any suitable type of wireless user equipment, such as a mobile phone, a portable data processing device, a portable web browser or a vehicle-mounted mobile station.

[0175] In general, various embodiments of the present application may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that can be executed by a controller, microprocessor, or other computing device, although the present application is not limited thereto.

[0176] Embodiments of the present application may be implemented by executing computer program instructions by a data processor of a mobile device, for example, in a processor entity, or by hardware, or by a combination of software and hardware. The computer program instructions may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages.

[0177] The block diagram of any logic flow in the drawings of the present application may represent program steps, or may represent interconnected logic circuits, modules and functions, or may represent a combination of program steps and logic circuits, modules and functions. A computer program may be stored on a memory. The memory may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology, such as but not limited to read-only memory (ROM), random access memory (RAM), optical storage devices and systems (digital versatile discs (DVD) or compact discs (CD)), etc. Computer-readable media may include non-transitory storage media. The data processor may be of any type suitable for the local technical environment, such as but not limited to a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FGPAs), and a processor based on a multi-core processor architecture.

Claims

1. A clock synchronization method, characterized in that: include: The source base station receives an indication from the UE that precise clock information is required; If the source base station determines that the user equipment UE meets the handover condition, the source base station sends a handover request to the target base station, where the handover request includes information requesting a precise clock; The source base station receives precise clock information of the target base station; wherein the precise clock information is a clock with a granularity of less than 10 milliseconds; The source base station sends first radio resource control (RRC) reconfiguration information to the UE, where the first RRC reconfiguration information includes the clock difference, and the clock difference is the difference between the clocks of the target base station and the source base station.

2. The method according to claim 1, characterized in that The source base station receives the precise clock information of the target base station, including: The source base station receives first signaling sent by the target base station and carrying precise clock information of the target base station.

3. The method according to claim 2, characterized in that The first signaling includes any one of the following: handover request confirmation, UE context retrieval request, XN-U address indication, and UE context release.

4. The method according to claim 1, wherein The source base station sends a handover request to the target base station, including: The source base station sends a handover request message to the core access and mobility management function AMF, where the handover request message includes information requesting a precise clock; The source base station receives the precise clock information of the target base station, including: The source base station receives the second signaling sent by the AMF and carrying the precise clock information of the target base station.

5. The method according to claim 4, characterized in that The second signaling includes any one of the following: a handover command, a path switch request confirmation, a UE context release command, a downlink radio access network RAN state change, paging, and location report control.

6. The method according to any one of claims 1 to 5, characterized in that Before the source base station determines that the UE meets the handover condition, the method further includes: The source base station receives a neighboring cell measurement report sent by the UE, where the neighboring cell measurement report includes an indication that precise clock information is required.

7. The method according to any one of claims 1 to 5, characterized in that Before the source base station determines that the UE meets the handover condition, the method further includes: The source base station sends a second RRC reconfiguration message to the UE, where the second RRC reconfiguration message includes a list of neighboring cells that support precise clock information indication.

8. The method according to claim 1, characterized in that The method further comprises: The source base station broadcasts system information block (SIB) information, where the SIB information includes a list of neighboring cells that support precise clock information indication.

9. The method according to claim 1, characterized in that The method further comprises: The source base station broadcasts system information block (SIB) information, where the SIB information includes a neighbor cell list including precise clock information of the neighbor cells.

10. A clock synchronization method, characterized in that: include: The UE sends an indication to the source base station that it needs precise clock information; The UE sends a neighboring cell measurement report to the source base station; The user equipment UE receives first radio resource control RRC reconfiguration information sent by the source base station, where the first RRC reconfiguration information includes a clock difference, where the clock difference is a difference between clocks of the target base station and the source base station; The precise clock information is a clock with a granularity of less than 10 milliseconds.

11. The method according to claim 10, characterized in that The neighbor cell measurement report includes an indication that precise clock information is required.

12. A clock synchronization method, characterized in that: include: The core access and mobility management function AMF receives the handover request message including the information requesting the precise clock sent by the source base station; The handover request message is sent by the source base station after receiving an indication from the UE that precise clock information is required and determining that the UE meets the handover condition; The AMF sends a handover request including information requesting a precise clock to the target base station; The AMF receives second signaling sent by the target base station and carrying precise clock information of the target base station; The AMF sends a third signaling carrying the precise clock information of the target base station to the source base station; The third signaling is used to enable the source base station to send a first radio resource control RRC reconfiguration message to the UE, where the first RRC reconfiguration message includes the clock difference, where the clock difference is the difference between the clocks of the target base station and the source base station; The precise clock information is a clock with a granularity of less than 10 milliseconds.

13. A clock synchronization method, characterized in that: include: The target base station receives a handover request message including a request for precise clock information sent by the source base station or a handover request message including a request for precise clock information sent by the core access and mobility management function AMF; The handover request message is sent by the source base station after receiving an indication sent by the UE that precise clock information is required and determining that the UE meets the handover condition; or the handover request message is sent by the AMF after receiving a handover request message sent by the source base station including information requesting a precise clock, and the handover request message is sent by the source base station after receiving an indication sent by the UE that precise clock information is required and determining that the UE meets the handover condition; The target base station sends the precise clock information to the source base station through the first signaling or sends the precise clock information to the AMF through the third signaling; The precise clock information is used to enable the source base station to send a first radio resource control RRC reconfiguration message to the UE, where the first RRC reconfiguration information includes the clock difference, where the clock difference is the difference between the clocks of the target base station and the source base station; The precise clock information is a clock with a granularity of less than 10 milliseconds.

14. A base station, comprising: A processor and a memory, characterized in that the processor is used to run program instructions stored in the memory to execute the clock synchronization method according to any one of claims 1-9 and claim 13.

15. A UE, characterized in that: include: It comprises a processor and a memory, wherein the processor is used to run program instructions stored in the memory to execute the clock synchronization method according to any one of claims 10-11.

16. A core access and mobility management function (AMF), comprising: A processor and a memory, wherein the processor is configured to run program instructions stored in the memory to execute the clock synchronization method according to claim 12.

17. A storage medium, characterized in that: The storage medium stores a computer program, and when the computer program is executed by a processor, the clock synchronization method according to any one of claims 1 to 13 is implemented.

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