WO2020156343A1

WO2020156343A1 - Clock synchronization method and device

Info

Publication number: WO2020156343A1
Application number: PCT/CN2020/073341
Authority: WO
Inventors: 黄曲芳; 范强; 徐小英; 娄崇
Original assignee: 华为技术有限公司
Priority date: 2019-02-01
Filing date: 2020-01-20
Publication date: 2020-08-06
Also published as: CN111526577A

Abstract

Embodiments of the present application relate to the field of communications. Disclosed are a clock synchronization method and device, for solving the problem of great clock synchronization errors between a terminal and a network device. The specific solution is that: a terminal obtains first information, the first information being used for determining a transmission time delay between a terminal and a network device; the terminal obtains a first time value, the first time value being used for indicating a sending time of a frame boundary of a radio frame of a first cell of the network device; the terminal determines, according to the obtained transmission delay and first time value, a second time value corresponding to a receiving time of the frame boundary of the radio frame of the first cell.

Description

Clock synchronization method and equipment

This application claims the priority of a Chinese patent application filed with the State Intellectual Property Office on February 1, 2019, the application number is 201910106165.X, and the application name is "a method and equipment for clock synchronization", the entire content of which is incorporated by reference In this application.

Technical field

The embodiments of the present application relate to the field of communications, and in particular to a clock synchronization method and device.

Background technique

In the existing communication system, each node that communicates with each other needs to realize clock synchronization. Currently, the main methods of clock synchronization are: Global Positioning System (GPS) and 1588. In the GPS mode, each node can obtain accurate time by receiving signals from GPS satellites to achieve clock synchronization. The GPS method requires nodes to be able to directly receive signals from GPS satellites. Nodes located indoors cannot directly receive signals from GPS satellites. In the 1588 mode, a node (such as a master node) can be elected within a certain range. The clock on the master node is used as the master clock, and other nodes (such as slave nodes) The clock on) should be synchronized with the master clock as much as possible, that is, clock synchronization is realized. The premise of clock synchronization in the 1588 mode is that the transmission delay from the master node to the slave node is the same as the transmission delay from the slave node to the master node. However, the terminal is not necessarily located outdoors. In addition, the transmission delay from the network device to the terminal is different from the transmission delay from the terminal to the network device. Therefore, the terminal is not suitable for using GPS or 1588 to synchronize clocks with network devices. Therefore, a clock synchronization method and device are needed to solve the problem of clock synchronization between the terminal and the network device.

Summary of the invention

In view of this, the embodiments of the present application provide a clock synchronization method and device to solve the problem of clock synchronization between a terminal and a network device.

In the first aspect, an embodiment of the present application provides a clock synchronization method. The method may include: the terminal obtains first information for determining the transmission delay between the terminal and the first network device, and obtains the first information indicating the first network device. The first time value of the transmission time of the frame boundary of the radio frame of the cell, the terminal can determine the second time value corresponding to the reception time of the frame boundary of the radio frame of the first cell according to the acquired transmission delay and the first time value To complete clock synchronization.

With reference to the first aspect, in a possible implementation manner, the foregoing first information may be information used to indicate a transmission delay.

With reference to the first aspect or the foregoing possible implementation manners, in another possible implementation manner, the foregoing first information may be information used to indicate the distance between the terminal and the first network device; correspondingly, the foregoing method may also Including: the terminal can obtain the transmission delay according to the distance between the terminal and the first network device. That is, the terminal can acquire the transmission delay between the terminal and the first network device according to the acquired information used to indicate the distance. Instead of using TA to obtain the transmission delay, that is, without first sending a signal (such as a preamble) to the first network device, the transmission delay with the first network device can be obtained.

In combination with the first aspect or the foregoing possible implementation manners, in another possible implementation manner, the foregoing method may further include: the terminal acquires the movement distance of the terminal from the moment when the first information is acquired to the current moment; when the movement distance is greater than The distance threshold indicates that the transmission delay between the terminal and the first network device may have changed. The terminal can send to the first network device the first instruction information for instructing the first network device to re-issue the first information, so that The first network device re-delivers the first information used to determine the transmission delay between the terminal and the first network device to the terminal.

In combination with the first aspect or the foregoing possible implementation manners, in another possible implementation manner, since the terminal may have errors when performing frame boundary detection of radio frames, in order to reduce such errors as much as possible, the method can also Including: the terminal acquires the receiving moments of the frame boundaries of the radio frames of M cells, the frame boundaries of the radio frames of the M cells are aligned, the M cells include the first cell, and M is an integer greater than or equal to 2; the terminal is based on the M cells The receiving time of the frame boundary of the radio frame of the first cell is updated. In other words, the terminal can detect the frame boundaries of the radio frames of multiple cells, and then finally determine the frame boundaries of the radio frames according to the detected results.

With reference to the first aspect or the foregoing possible implementation manners, in another possible implementation manner, the terminal obtains the first time value, which may specifically include: the terminal may receive M cells indicating the transmission time of the frame boundary of the radio frame Time value, the frame boundaries of the radio frames of the M cells are aligned, the M cells include the first cell, and M is an integer greater than or equal to 2, and then the first time value is determined according to the acquired time values of the M cells.

In combination with the first aspect or the foregoing possible implementation manners, in another possible implementation manner, under the condition that the sending period of the timing message in each cell remains unchanged, the first network device can ensure that the The sending period of the timing message of each cell is staggered, so that the terminal can read the timing message more frequently. That is, in the M cells, the time window for the terminal to receive the time value of the transmission time indicating the frame boundary of the radio frame in different cells is different; correspondingly, the method may also include: the terminal may receive the data from the first network device The second indication information, the second indication information may be used to indicate the time window for receiving the time value of the sending moment of the frame boundary of the radio frame of the receiving cell in each of the N cells. The N cells include M cells, N is an integer greater than or equal to M; the terminal receives the time value of the transmission time indicating the frame boundary of the radio frame of the M cells, which may specifically include: the terminal receives the time of the M cells according to the time window indicated by the second indication information value.

With reference to the first aspect or the foregoing possible implementation manners, in another possible implementation manner, in order to allow the first network device to allocate an appropriate number of cells to the terminal, the method may further include: the terminal may send to the first network device Third indication information, the third indication information is used by the first network device to allocate cells for the terminal, and the cells allocated for the terminal include M cells; wherein, the third indication information is the terminal's clock accuracy requirement for the terminal; or, The third indication information is the identification of the first service of the terminal or the quality of service QoS identification of the first service, and the accuracy requirements of the first service of the terminal on the clock of the terminal are greater than the accuracy requirements of other services of the terminal on the clock of the terminal.

With reference to the first aspect or the foregoing possible implementation manners, in another possible implementation manner, the method may further include: the terminal receives a third time value sent by the first network device, and the third time value is used to indicate the second network The sending moment of the subframe boundary of the second cell of the device; the terminal obtains the fourth time value after switching to the second cell, and the fourth time value is used to indicate the receiving moment of the subframe boundary of the second cell; The time value and the fourth time value determine the transmission delay between the terminal and the second network device; the terminal performs data transmission according to the transmission delay between the terminal and the second network device.

In combination with the first aspect or the foregoing possible implementation manners, in another possible implementation manner, the method may further include: obtaining the system frame number of the second cell after the terminal switches to the second cell of the second network device, Receive the fifth time value sent by the second network device, the fifth time value is used to indicate the sending moment of the frame boundary of the radio frame of the second cell; the terminal obtains the sixth time value according to the system frame number, and the sixth time value is used At the receiving time indicating the frame boundary of the radio frame of the second cell; the terminal determines the transmission delay between the terminal and the second network device according to the fifth time value and the sixth time value; the terminal according to the transmission time between the terminal and the second network device Delay data transmission.

In a second aspect, an embodiment of the present application provides a clock synchronization method. The method may include: the first network device obtains the distance between the terminal and the first network device, and generates a method for determining the terminal and the first network based on the distance. And send the first information about the transmission delay of the device to the terminal.

With reference to the second aspect, in a possible implementation manner, the first network device sends to the terminal a time value indicating the transmission time of the frame boundary of the radio frame through the cell allocated for the terminal, where the cell allocated for the terminal is Contains the first cell.

With reference to the second aspect or the foregoing possible implementation manners, in another possible implementation manner, the first information may be information used to indicate transmission delay; or, the first information may be used to indicate whether the terminal is connected to the first network Information about the distance between devices.

With reference to the second aspect or the foregoing possible implementation manners, in another possible implementation manner, the method further includes: the first network device obtains the distance between the terminal and the first network device; The distance between the network devices has changed compared to the distance between the terminal and the first network device when the first network device delivers the first information, indicating that the transmission delay between the terminal and the first network device may have occurred Change, the first network device sends the first information to the terminal again.

With reference to the second aspect or the foregoing possible implementation manners, in another possible implementation manner, the cells allocated to the terminal include N cells, the frame boundaries of the radio frames of the N cells are aligned, and N is an integer greater than or equal to 2. .

In combination with the second aspect or the foregoing possible implementation manners, in another possible implementation manner, when the sending period of the timing message in each cell remains unchanged, the first network device can ensure that the The sending period of the timing message of each cell is staggered, so that the terminal can read the timing message more frequently. The first network device sends the time value indicating the sending moment of the frame boundary of the radio frame to the terminal through the cell allocated for the terminal. Specifically, it may include: the first network device passes through each of the N cells in different time windows. Cell, sending a time value indicating the sending moment of the frame boundary of the radio frame to the terminal; the method may further include: the first network device sends second indication information to the terminal, the second indication information is used to indicate that the terminal is in each of the N cells A time window indicating the time value of the transmission time of the frame boundary of the radio frame in the receiving cell in each cell.

In combination with the second aspect or the foregoing possible implementation manners, in another possible implementation manner, in order to be able to allocate a suitable number of cells to the terminal, the first network device may allocate cells to the terminal according to the instructions of the terminal. That is, the method may further include: the first network device receives third instruction information from the terminal; the first network device obtains the number X of cells that need to be allocated to the terminal according to the third instruction information; The terminal allocates N cells, and N is greater than or equal to the number X; where: the third indication information is the terminal's requirements for the accuracy of the terminal's clock, and different accuracy requirements correspond to different numbers X; or, the third indication information is the terminal's first service The identifier of different services corresponds to a different quantity X; or, the third indication information is the quality of service QoS identifier of the first service, and different QoS identifiers correspond to a different quantity X; the accuracy of the terminal’s first service to the terminal’s clock The requirements are greater than the accuracy requirements of other services of the terminal on the clock of the terminal.

With reference to the second aspect or the foregoing possible implementation manners, in another possible implementation manner, the method may further include: the first network device receives a third time value sent by the second network device, and the third time value is used to indicate The sending moment of the subframe boundary of the second cell of the second network device; the first network device sends the third time value to the terminal.

In a third aspect, an embodiment of the present application provides a clock synchronization device. The clock synchronization device includes units or means for performing the steps of the first aspect above. Specifically: the clock synchronization apparatus may include: a first obtaining unit, configured to obtain first information, and a first time value, the first information is used to determine the transmission delay between the clock synchronization apparatus and the first network device, and the first time The value is used to indicate the sending moment of the frame boundary of the radio frame of the first cell of the first network device; the determining unit is used to determine the receiving moment of the frame boundary of the radio frame of the first cell according to the transmission delay and the first time value The corresponding second time value.

With reference to the third aspect, in a possible implementation manner, the first information is information used to indicate a transmission delay.

With reference to the third aspect or the foregoing possible implementation manners, in another possible implementation manner, the first information is information used to indicate the distance between the clock synchronization apparatus and the first network device; the first acquiring unit further uses The transmission delay is obtained according to the distance between the clock synchronization device and the first network device.

With reference to the third aspect or the foregoing possible implementation manners, in another possible implementation manner, the clock synchronization device may further include: a second acquiring unit and a sending unit; the second acquiring unit is used to acquire the The moving distance from the moment of the first information to the current moment; the sending unit is used to send the first indication information to the first network device when the moving distance is greater than the distance threshold, and the first indication information is used to instruct the first network device to reissue First information.

With reference to the third aspect or the foregoing possible implementation manners, in another possible implementation manner, the clock synchronization device may further include: an update unit; a first acquisition unit, which is also used to acquire frame boundaries of radio frames of M cells At the receiving moment, the frame boundaries of the radio frames of the M cells are aligned, the M cells include the first cell, and M is an integer greater than or equal to 2; the update unit is used to receive the frame boundaries of the radio frames of the M cells according to the receiving moment, Update the receiving time of the frame boundary of the radio frame of the first cell.

With reference to the third aspect or the foregoing possible implementation manners, in another possible implementation manner, the clock synchronization device may further include: a receiving unit; a receiving unit, configured to receive M cells indicating the sending time of the frame boundary of the radio frame The frame boundaries of the radio frames of the M cells are aligned, the M cells include the first cell, and M is an integer greater than or equal to 2; the first acquiring unit is specifically used to determine the first cell based on the time values of the M cells A time value.

In combination with the third aspect or the foregoing possible implementation manners, in another possible implementation manner, in the M cells, the clock synchronization device receives different time windows indicating the time values of the transmission time of the frame boundary of the radio frame from different cells. The receiving unit is further configured to receive second indication information from the first network device, the second indication information is used to indicate the time value of the sending moment indicating the frame boundary of the radio frame of the receiving cell in each of the N cells The N cells include M cells; the receiving unit is specifically configured to receive the time values of the M cells according to the time window indicated by the second indication information.

With reference to the third aspect or the foregoing possible implementation manners, in another possible implementation manner, the clock synchronization apparatus may further include: a sending unit, configured to send third indication information to the first network device, and the third indication information is used for The first network device allocates cells for the clock synchronization device, and the cells allocated for the clock synchronization device include M cells; where the third indication information is the accuracy requirement of the clock synchronization device for the clock synchronization device; or, the third indication information It is the identification of the first service of the clock synchronization device or the quality of service QoS identification of the first service. The first service of the clock synchronization device requires more precision for the clock of the clock synchronization device than for other services of the clock synchronization device. Precision requirements.

With reference to the third aspect or the foregoing possible implementation manners, in another possible implementation manner, the clock synchronization device may further include: a receiving unit and a transmission unit; the receiving unit is configured to receive the third time value sent by the first network device , The third time value is used to indicate the sending moment of the subframe boundary of the second cell of the second network device; the second obtaining unit is also used to obtain the fourth time value after switching to the second cell, the fourth time value It is used to indicate the receiving moment of the subframe boundary of the second cell; the determining unit is also used to determine the transmission delay between the clock synchronization device and the second network device according to the third time value and the fourth time value; the transmission unit is used to Data transmission is performed according to the transmission delay between the clock synchronization device and the second network device.

With reference to the third aspect or the foregoing possible implementation manners, in another possible implementation manner, the clock synchronization apparatus may further include: a transmission unit; and the first acquisition unit is further configured to switch to the second cell of the second network device After that, the system frame number SFN of the second cell is acquired, and the fifth time value sent by the second network device is received. The fifth time value is used to indicate the sending moment of the frame boundary of the radio frame of the second cell; the second acquiring unit, It is also used to obtain the sixth time value according to the SFN, the sixth time value is used to indicate the receiving moment of the frame boundary of the radio frame of the second cell; the determining unit is also used to determine according to the fifth time value and the sixth time value The transmission delay between the clock synchronization device and the second network device; the transmission unit is used for data transmission according to the transmission delay between the clock synchronization device and the second network device.

In a fourth aspect, an embodiment of the present application provides a clock synchronization device. The clock synchronization device may include units or means for performing the steps of the second aspect above. Specifically, the clock synchronization device may include: an acquiring unit, configured to acquire the distance between the terminal and the clock synchronization device, and generating first information according to the distance; and a sending unit, configured to send the first information to the terminal, the first information Used by the terminal to determine the transmission delay between the terminal and the clock synchronization device.

With reference to the fourth aspect, in a possible implementation manner, the sending unit is further configured to send a time value indicating the sending time of the frame boundary of the radio frame to the terminal through the cell allocated for the terminal, and the cell allocated for the terminal includes The first cell.

With reference to the fourth aspect or the foregoing possible implementation manners, in another possible implementation manner, the first information is information used to indicate the transmission delay; or, the first information is used to indicate the communication between the terminal and the clock synchronization device. Distance information.

With reference to the fourth aspect or the foregoing possible implementation manners, in another possible implementation manner, the clock synchronization device may further include: an acquiring unit, which is also used to acquire the distance between the terminal and the clock synchronization device; and a sending unit, which also uses When the acquired distance between the terminal and the clock synchronization device is compared with the distance between the terminal and the clock synchronization device when the clock synchronization device sends the first information, the first information is re-sent to the terminal.

With reference to the fourth aspect or the foregoing possible implementation manners, in another possible implementation manner, the cells allocated to the terminal include N cells, and the frame boundaries of the radio frames of the N cells are aligned, and N is an integer greater than or equal to 2. .

In combination with the fourth aspect or the foregoing possible implementation manners, in another possible implementation manner, the sending unit is specifically configured to send an instruction radio frame to the terminal through each of the N cells in different time windows. The time value of the sending moment of the frame boundary; the sending unit is also used to send second indication information to the terminal, and the second indication information is used to instruct the terminal to receive the frame boundary of the radio frame indicating the cell in each of the N cells The time window of the time value at the time of sending.

With reference to the fourth aspect or the foregoing possible implementation manners, in another possible implementation manner, the clock synchronization device may further include: a receiving unit and a distribution unit; a receiving unit for receiving the third indication information from the terminal; an acquiring unit , Is also used to obtain the number X of cells that need to be allocated to the terminal according to the third indication information; the allocation unit is used to allocate N cells to the terminal according to the number X, where N is greater than or equal to the number X; where: third indication information It is the terminal’s requirements for the terminal’s clock accuracy, and different accuracy requirements correspond to different numbers X; or, the third indication information is the identification of the first service of the terminal, and the identifications of different services correspond to different numbers X; or, the third indication information It is the quality of service QoS identifier of the first service, and different QoS identifiers correspond to different numbers X; the terminal's first service requires more precision for the terminal clock than other services of the terminal require for the terminal's clock.

With reference to the fourth aspect or the foregoing possible implementation manners, in another possible implementation manner, the receiving unit is further configured to receive a third time value sent by the second network device, and the third time value is used to indicate the second network device The sending moment of the subframe boundary of the second cell; the sending unit is further configured to send the third time value to the terminal.

In a fifth aspect, an embodiment of the present application provides a clock synchronization device. The clock synchronization device may include a processor and an interface circuit. The processor is configured to communicate with other devices, such as network equipment, through the interface circuit, and perform the above The method provided in the first aspect. The processor may include one or more.

In a sixth aspect, an embodiment of the present application provides a clock synchronization device. The clock synchronization device may include a processor and an interface circuit. The processor is configured to communicate with other devices, such as a terminal, through the interface circuit, and execute the above-mentioned Two methods provided. The processor may include one or more.

In a seventh aspect, an embodiment of the present application provides a clock synchronization device. The clock synchronization device may include a processor, configured to be connected to a memory, and used to call a program stored in the memory to execute the method provided in the first aspect. . The memory can be located inside the device or outside the device. And the processor includes one or more.

In an eighth aspect, an embodiment of the present application provides a terminal, and the terminal may include the clock synchronization device provided in the above second aspect.

In a ninth aspect, an embodiment of the present application provides a network device, and the network device may include the clock synchronization device provided in the foregoing third aspect.

In a tenth aspect, an embodiment of the present application provides a computer-readable storage medium, including: computer software instructions; when the computer software instructions run in a clock synchronization device or a chip built in the clock synchronization device, the clock synchronization device executes the above-mentioned One aspect or the second aspect of the method.

In an eleventh aspect, an embodiment of the present application provides a clock synchronization program, which is used to execute the method of the first aspect or the second aspect when executed by a processor.

In a twelfth aspect, an embodiment of the present application provides a program product, such as a computer-readable storage medium, including the above program.

It can be seen that in the above aspects, the terminal can obtain a relatively accurate transmission delay. In this way, the terminal performs clock synchronization according to the obtained relatively accurate transmission delay, which can reduce the clock synchronization error between the terminal and the first network device.

As shown above, the terminal can obtain the first information for determining the transmission delay, as received from the first network device. The first information may be that the first network device measures the distance between the first network device and the terminal by means of radar or wireless positioning, and the obtained distance or the distance between the first network device and the terminal determined according to the measured distance The transmission delay obtained in this way is more accurate than using TA to determine the transmission delay.

In addition, the terminal determines the frame boundary of the wireless frame by acquiring the receiving time of the frame boundary of the wireless frame of multiple cells, which can reduce the error when the terminal determines the frame boundary of the wireless frame, thereby further reducing the terminal and the first network device The synchronization error between the clocks. When the first network device notifies the terminal of the time value, the wireless frame of the time value sent has no time constraint, that is, the first network device can determine the wireless frame that notifies the terminal of the time value according to its own schedule. For example, in which wireless frame the load of the first network device is light, which wireless frame is used to notify the terminal of the time value. After the terminal is handed over to the target cell (such as the second cell of the second network device described above), it does not need to perform random access, and the precise time of the transmission time of the subframe boundary notified by the second network device, or by reading the target cell The timing message can obtain the TA, and then perform data transmission in the target cell.

Description of the drawings

FIG. 1 is a schematic diagram of a communication system provided by an embodiment of this application;

Figure 2 is a schematic diagram of a network architecture provided by an embodiment of the application;

FIG. 3 is a schematic diagram of another network architecture provided by an embodiment of the application;

4 is a schematic diagram of transmission of a timing message provided by an embodiment of the application;

FIG. 5 is a schematic flowchart of a clock synchronization method provided by an embodiment of this application;

FIG. 6 is a schematic flowchart of another clock synchronization method provided by an embodiment of this application;

FIG. 7 is a schematic diagram of the transmission of another timing message provided by an embodiment of the application;

FIG. 8 is a schematic flowchart of another clock synchronization method provided by an embodiment of this application;

FIG. 9 is a schematic diagram of the transmission of yet another timing message provided by an embodiment of the application;

FIG. 10 is a schematic diagram of transmission of yet another timing message provided by an embodiment of this application;

FIG. 11 is a schematic flowchart of another clock synchronization method provided by an embodiment of this application;

FIG. 12 is a schematic flowchart of another clock synchronization method provided by an embodiment of this application;

FIG. 13 is a schematic structural diagram of a network device provided by an embodiment of this application;

FIG. 14 is a schematic structural diagram of a terminal provided by an embodiment of the application.

detailed description

Hereinafter, some terms in this application are explained:

1) Terminal, also known as user equipment (UE), mobile station (MS), mobile terminal (MT), etc., is a device that provides users with voice/data connectivity . For example, the operating arm terminal in the industrial control network. For another example, a handheld device with a wireless connection function, or a vehicle-mounted device, etc. At present, some examples of terminals are: mobile phones, tablet computers, notebook computers, handheld computers, mobile internet devices (MID), wearable devices, virtual reality (VR) devices, augmented reality (augmented reality, AR) equipment, industrial control (industrial control) wireless terminal, unmanned driving (self driving) wireless terminal, remote medical surgery (remote medical surgery) wireless terminal, smart grid (smart grid) The wireless terminal in the transportation safety (transportation safety), the wireless terminal in the smart city (smart city), or the wireless terminal in the smart home (smart home), etc.

2) The network device is a device in a wireless network, for example, a radio access network (RAN) node that connects a terminal to the wireless network. At present, some examples of RAN nodes are: gNB, transmission reception point (TRP), evolved Node B (evolved Node B, eNB), radio network controller (RNC), Node B (Node B) B, NB), base station controller (BSC), base transceiver station (BTS), home base station (for example, home evolved NodeB, or home Node B, HNB), baseband unit (baseband unit) , BBU), or wireless fidelity (Wifi) access point (AP), etc. In a network structure, the network device may include a centralized unit (CU) node, or a distributed unit (DU) node, or a RAN device including a CU node and a DU node.

3) "Multiple" means two or more than two, and other measure words are similar. "And/or" describes the association relationship of the associated object, indicating that there can be three types of relationships, for example, A and/or B, which can mean: A alone exists, A and B exist at the same time, and B exists alone. In addition, for elements in the singular form "a", "an" and "the", unless the context clearly dictates otherwise, it does not mean "one or only one", but means "one or more At one". For example, "a device" means to one or more such devices. Furthermore, at least one (at least one of)..." means one or any combination of subsequent associated objects, for example, "at least one of A, B, and C" includes A, B, C, AB, AC, BC, or ABC.

Please refer to FIG. 1, which is a schematic diagram of a communication system provided by an embodiment of the application. As shown in FIG. 1, a terminal 101 (the operating arm terminal shown in FIG. 1) accesses a wireless network to obtain services from an external network (such as the Internet) through the wireless network, or communicate with other terminals through the wireless network. The wireless network may include a RAN 102 and a core network (core network, CN) 103. Among them, the RAN 102 is used to connect the terminal 101 to the wireless network, and the CN 103 is used to manage the terminal and provide a gateway for communication with the external network.

Please refer to FIG. 2, which is a schematic diagram of a network architecture provided by an embodiment of the application. As shown in Figure 2, the network architecture includes CN equipment and RAN equipment.

The RAN equipment includes a baseband device and a radio frequency device. The baseband device can be implemented by one node or by multiple nodes. The radio frequency device can be implemented separately from the baseband device, or integrated into the baseband device, or partially remote Integrated in the baseband device. For example, in the Long Term Evolution (LTE) communication system, the RAN equipment (eNB) includes a baseband device and a radio frequency device. The radio frequency device can be arranged remotely from the baseband device, such as a remote radio unit. RRU) is arranged remotely relative to BBU.

The communication between the RAN equipment and the terminal follows a certain protocol layer structure. For example, the control plane protocol layer structure can include the radio resource control (RRC) layer, the packet data convergence protocol (PDCP) layer, the radio link control (RLC) layer, and the media interface. Access control (media access control, MAC) layer and physical layer (physical layer, PHY) and other protocol layer functions. The user plane protocol layer structure can include the functions of the PDCP layer, the RLC layer, the MAC layer, and the physical layer; in one implementation, the PDCP layer can also include a service data adaptation protocol (SDAP) layer .

The functions of these protocol layers can be implemented by one node or multiple nodes; for example, in an evolution structure, the RAN device can include a centralized unit (CU) and a distributed unit (DU), Multiple DUs can be centrally controlled by one CU. As shown in Figure 2, CU and DU can be divided according to the protocol layers of the wireless network. For example, the functions of the PDCP layer and above are set in the CU, and the protocol layers below the PDCP, such as the RLC layer and MAC layer, are set in the DU.

The division of this protocol layer is just an example, and it can also be divided in other protocol layers, for example, in the RLC layer, setting the functions of the RLC layer and above protocol layers in the CU, and setting the functions of the protocol layers below the RLC layer in the DU; Or, in a certain protocol layer, for example, part of the functions of the RLC layer and the functions of the protocol layer above the RLC layer are set in the CU, and the remaining functions of the RLC layer and the functions of the protocol layer below the RLC layer are set in the DU. In addition, it can also be divided in other ways, for example, by time delay. Functions that need processing time to meet the delay requirements are set in the DU, and functions that do not need to meet the delay requirements are set in the CU.

In addition, the radio frequency device can be remote, not placed in the DU, can also be integrated in the DU, or part of the remote part is integrated in the DU, and there is no restriction here.

Please continue to refer to Figure 3. Compared with the architecture shown in Figure 2, the control plane (CP) and the user plane (UP) of the CU can also be separated and divided into different entities for implementation, namely the control plane CU entity (CU-CP entity) ) And the user plane CU entity (CU-UP entity).

In the above network architecture, the signaling generated by the CU can be sent to the terminal through the DU, or the signaling generated by the terminal can be sent to the CU through the DU. The DU may directly pass the protocol layer encapsulation without analyzing the signaling and transparently transmit it to the terminal or CU. If the following embodiments involve the transmission of such signaling between the DU and the terminal, at this time, the sending or receiving of the signaling by the DU includes this scenario. For example, the RRC or PDCP layer signaling is finally processed as PHY layer signaling and sent to the terminal, or converted from received PHY layer signaling. Under this architecture, the RRC or PDCP layer signaling can also be considered to be sent by the DU, or sent by the DU and radio frequency.

In the above embodiment, the CU is divided into network equipment on the RAN side. In addition, the CU may also be divided into network equipment on the CN side, which is not limited here.

The devices in the following embodiments of the present application may be located in terminals or network devices according to the functions they implement. When the above CU-DU structure is adopted, the network device may be a CU node, or a DU node, or a RAN device including a CU node and a DU node.

In an existing communication system, each node that needs to communicate with each other (such as between different network devices, between network devices and terminals) can achieve clock synchronization. The main methods of clock synchronization are GPS and 1588. However, it is not applicable to the terminal.

Therefore, a clock synchronization method applicable to the terminal is proposed. Specifically, the network device notifies the terminal of the time value used to indicate the end position of a certain wireless frame, and the terminal uses the time value and the transmission delay to synchronize the clock.

Wherein, the time value notified by the network device to the terminal specifically indicates the time when the network device sends the end position of the wireless frame. For example, as shown in FIG. 4, the network device carries the time value used to indicate the time when the network device sends the end position of the wireless frame M in the wireless frame M-2 and sends it to the terminal. For example, the network device notifies the terminal in the wireless frame M-2 that the time value corresponding to the end position of the wireless frame M is 485ms793.25us at 14:30:28 on December 22, 2018.

After receiving the wireless frame M-2, the terminal can learn that the time value corresponding to the end position of the wireless frame M sent by the network device is 485ms793.25us at 14:30:28 on December 22, 2018. The terminal may also detect the time when the end position of the wireless frame M is received. For example, the time at which the terminal detects the end position of the wireless frame M is T1.

Since there will be a transmission delay between the network device and the terminal, the time value corresponding to the time when the network device sends the end position of the wireless frame M obtained by the terminal plus the transmission delay should be equal to the wireless frame M detected by the terminal The time value corresponding to the end position. In this way, the terminal clock can be synchronized with the network device clock. In other words, the terminal can determine the time corresponding to the end position of the wireless frame M detected by the terminal (such as T1) corresponding to the time value and transmission delay corresponding to the time when the network device sends the end position of the wireless frame M. Time value. For example, if the transmission delay is 200us, the terminal can determine that the time value corresponding to T1 is 485ms993.25us at 14:30:28 on December 22, 2018. In this way, the clock between the terminal and the network device is synchronized.

It can be seen that the terminal needs to know the transmission delay between the network device and the terminal before it can synchronize the clock according to the time value notified by the network device. The terminal can determine the timing advance (timing advance, TA), and then use one-half of the TA as the transmission delay.

There will be errors in clock synchronization using the above method. Among them, the error introduced by this method can be seen in Table 1. It can be seen from Table 1 that the timing error type under this method can include: base station transmission frame timing (BS transmit frame timing), UE receiving frame timing (UE receiving frame timing), UE transmission frame timing (UE transmit) frame timing (TA adjustment accuracy), TA adjustment granularity (TA adjustment granularity), base station receiving frame timing (BS receiving frame timing). In addition, under different sub-carrier spacing (SCS), the error introduced by the same timing error type may be different, and the total timing error (Total Timing Error) may also be different. For example, when the SCS is equal to 15kHz, the error introduced by the UE receiving frame timing is [12]*64*Tc (Tc is the minimum time unit), and the total timing error is [38]*64*Tc. When SCS is equal to 30kHz, the error introduced by the UE receiving frame timing is [8]*64*Tc, and the total timing error is [26]*64*Tc.

Table 1

Among them, in Table 1, UE transmission frame timing (TA adjustment accuracy), TA adjustment granularity, and base station receiving frame timing all come from TA. In other words, the TA error determined by the terminal is relatively large. If one-half of the TA is used as the transmission delay, this will make the transmission delay error determined by the terminal larger, resulting in a larger synchronization error of the clock between the terminal and the network device.

Based on this, a clock synchronization method is provided: the network device uses radar or wireless positioning to measure the distance between the network device and the terminal, and the measured distance or the determined distance between the network device and the terminal are determined based on the measured distance. The terminal is notified of the transmission delay between time. The transmission delay obtained in this way is more accurate than using TA to determine the transmission delay. In other words, the terminal can obtain a more accurate transmission delay. In this way, the terminal performs clock synchronization according to the obtained relatively accurate transmission delay, which can reduce the clock synchronization error between the terminal and the network device.

It should be noted that the clock synchronization method described in the embodiments of the present application can be applied to an industrial control network. The industrial control network can be based on the communication system shown in Figure 1 above. As an example, the above-mentioned communication system may be a 5G NR system. Of course, the above-mentioned communication system may also be another communication system, as long as it is a communication system supported by an industrial control network, and the embodiments of the present application are not specifically limited herein.

The clock synchronization method provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

FIG. 5 is a schematic flowchart of a clock synchronization method provided by an embodiment of this application. As shown in FIG. 5, the method may include:

501. The first network device sends first information to the terminal.

502. The terminal obtains the foregoing first information, where the first information is used to determine the transmission delay between the terminal and the first network device.

In some embodiments, the first information may be information used to indicate the transmission delay between the terminal and the first network device. The first information specifically may be the transmission delay itself, or may be indication information used to indicate the transmission delay.

The first information in this embodiment is different from the TA in that it is not obtained through signaling interaction between the network device and the terminal, and has the characteristic of more accurately characterizing the distance or time delay between the network device and the terminal.

Exemplarily, the first network device may obtain the distance between the terminal and the first network device. For example, the first network device may obtain the distance between the terminal and the first network device through radar measurement. The first network device may also measure the distance between the terminal and the first network device through wireless positioning. The distance obtained by the first network device may be a result obtained after one measurement, or may be a result obtained by averaging or weighting the results obtained from multiple measurements.

The first network device may generate the foregoing first information according to the acquired distance. For example, the first network device can determine the transmission delay between the terminal and the first network device according to the obtained distance between the terminal and the first network device.

For example, the first network device divides the acquired distance by the speed of light to determine the transmission delay between itself and the terminal. For another example, there may be a multipath offset between the first network device and the terminal. When determining the transmission time delay between the first network device and the terminal, the transmission time delay caused by the multipath offset may also be taken into consideration. For example, the terminal is an operating arm terminal located in a factory building as an example. Various obstructions may exist between the first network device and the terminal of the operating arm, resulting in a multipath offset between the first network device and the terminal of the operating arm. Therefore, the first network device may divide the obtained distance between the operating arm terminal and the first network device by the speed of light to determine the transmission delay 1, and determine the transmission delay 2 due to the multipath offset according to the channel transmission model. The first network device can obtain the transmission delay between the operator arm terminal and the first network device according to the transmission delay 1 and the transmission delay 2 (for example, the transmission delay 1 and the transmission delay 2 are summed to obtain the operation arm terminal and the second The transmission delay of a network device).

Among them, the channel transmission model is determined by the first network device, and it includes the probability distribution of the transmission delay at different distances (the distance between the terminal and the first network device), such as the line-of-sight direct transmission path at the first distance Transmission delay t_1, the probability is 95%, the transmission delay t-2 of the non-line-of-sight path, its probability is 5%; at the second distance, the transmission delay t_3 of the line-of-sight direct path, the probability is 90% , The transmission delay t_4 of the non-line-of-sight path, the probability is 10%, etc. According to the distance between the terminal and the first network device, the first network device can use the channel transmission model to determine the transmission delay 2 caused by the multipath offset. If the distance between the operating arm terminal and the first network device is the first distance, the transmission delay 2 is equal to the sum of t_1*95% and t_2*5%. Then, the first network device may notify the terminal of the obtained transmission delay or indication information for indicating the transmission delay.

Correspondingly, the terminal can obtain the transmission delay or the indication information used to indicate the transmission delay. If the terminal obtains the indication information for indicating the transmission delay, the terminal can determine the transmission delay between the terminal and the first network device according to the obtained indication information for indicating the transmission delay.

In other embodiments, the first information may be information used to indicate the distance between the terminal and the first network device. The first information may be the distance itself between the terminal and the first network device, or may be indication information used to indicate the distance. That is, after obtaining the distance between the terminal and the first network device, the first network device may send the obtained distance or the indication information used to indicate the distance to the terminal. Correspondingly, the terminal can obtain the distance between the terminal and the first network device or the indication information used to indicate the distance. According to the acquired distance between the terminal and the first network device or the indication information used to indicate the distance, the terminal can determine the transmission delay between the terminal and the first network device.

Of course, if the transmission delay caused by the multipath offset between the first network device and the terminal is considered, the first network device may also send the channel transmission model to the terminal. In this way, the terminal can determine the transmission delay between the terminal and the first network device according to the acquired information indicating the distance between the terminal and the first network device and the channel transmission model. Wherein, the first network device may carry the channel transmission model and the information used to indicate the distance between the terminal and the first network device in the same information (such as the first information) and transmit it to the terminal, or the channel transmission model The information used to indicate the distance between the terminal and the first network device is carried in different information and transmitted to the terminal, which is not specifically limited in this embodiment. It should be noted that, in this embodiment, the specific implementation of determining the transmission delay by the terminal may refer to the specific implementation of determining the transmission delay by the first network device, which will not be described in detail here.

It should be noted that the above example is described by taking the first information delivered to the terminal by the first network device as an example, that is, the above step 502 may specifically be that the terminal receives the first information from the first network device. . Of course, the foregoing first information may also be obtained by the terminal in other ways, that is, the transmission delay between the terminal and the first network device may be obtained by the terminal in other ways. For example, the terminal can obtain the distance between itself and the first network device through radar measurement, and then determine the transmission delay with the first network device according to the measured distance. For another example, the terminal may use its own positioning module to measure the distance between itself and the first network device, and then determine the transmission delay with the first network device according to the measured distance. For another example, the terminal may also obtain the distance between itself and the first network device according to the configuration of the background, and then determine the transmission delay with the first network device according to the obtained distance. When the terminal obtains the first information in other ways, the foregoing step 501 may not be performed.

503. The first network device sends a time value indicating the sending moment of the frame boundary of the radio frame to the terminal through the cell allocated for the terminal, and the cell allocated for the terminal includes the first cell.

Among them, the frame boundary of the wireless frame may be the start position or the end position of the wireless frame. In addition, since the time value sent by the first network device to the terminal indicates the moment when the first network device sends the frame boundary of the wireless frame, for ease of description, in the embodiment of the present application, the first network device is sent to The time of the frame boundary of the wireless frame indicated by the time value of the terminal is called the transmission time of the frame boundary of the wireless frame.

The first network device may notify the terminal of a time value indicating the start position or end position of a certain radio frame through the cell allocated to the terminal, and the notified time value can be used for the terminal to perform clock synchronization. In some embodiments, the first network device may send a timing message to the terminal through a cell allocated to the terminal, and the timing message carries a time value indicating the sending time of the start position or the end position of the radio frame.

For example, the cells allocated to the terminal include the first cell, and the frame boundary of the radio frame is taken as an example. The first network device may send a timing message to the terminal in the radio frame M-2 through the first cell. The timing message carries a time value (for example, called the first time value), and the time value can be used to indicate the radio frame M The sending time of the ending position. Among them, the timing message can be sent to the terminal in a broadcast manner or a dedicated signaling manner.

It should be noted that the first network device may periodically send a time value indicating the transmission time of the frame boundary of the radio frame to the terminal through the cell allocated to the terminal, for the terminal to perform clock synchronization. The first network device can also send a time value indicating the sending time of the frame boundary of the radio frame to the terminal from a cell allocated to the terminal from time to time. For example, the first network device can determine that its own clock has a jump, pass The cell allocated by the terminal sends a time value indicating the transmission time of the frame boundary of the radio frame to the terminal for the terminal to synchronize clocks.

504. The terminal acquires a first time value, where the first time value is used to indicate the transmission time of the frame boundary of the radio frame of the first cell of the first network device.

For example, with reference to the example in step 503, step 504 may specifically be: the terminal receives the timing message sent by the first network device in the radio frame M-2 through the first cell, so as to obtain information indicating the first cell The time value of the sending moment of the end position of the wireless frame M is the first time value. For example, the first time value: 587ms323.25us at 13:14:36 on December 29, 2018.

505. The terminal determines the second time value corresponding to the receiving moment of the frame boundary of the radio frame of the first cell according to the transmission delay and the first time value.

Among them, for the terminal, it can obtain the frame boundary (starting position or ending position) time of a certain wireless frame through synchronization sequence detection, and the subsequent terminal will start or end receiving the wireless frame at this time. Therefore, For ease of description, in the embodiment of the present application, the time at which the frame boundary of the wireless frame is detected by the terminal is referred to as the receiving time of the frame boundary of the wireless frame. It should be noted that the time (such as the receiving time, the sending time) described in the embodiments of the present application refers to a point on the time axis. The time value corresponding to the time (such as the time value corresponding to the receiving time, the time value corresponding to the sending time) refers to the coordinate value corresponding to this point on the time axis.

In theory, the time value corresponding to the receiving moment of the frame boundary of the wireless frame detected by the terminal should be equal to the sum of the time value corresponding to the sending moment of the frame boundary of the wireless frame and the transmission delay, so that the terminal and the first network The clock of the device is synchronized. Therefore, after the terminal obtains the transmission delay between the terminal and the first network device, and the first time value indicating the transmission time of the frame boundary of the radio frame of the first cell, the transmission delay is compared with the first time value. Plus, the terminal can determine the second time value corresponding to the receiving moment of the frame boundary of the wireless frame, so as to realize the clock synchronization between the terminal and the first network device.

For example, in combination with the example of step 502 and step 504, the terminal can obtain the transmission delay (for example, the transmission delay is 300us) and the first time value (for example, the transmission time indicating the end position of the radio frame M in the first cell). The first time value: 13:14:36, December 29, 2018, 587ms323.25us), the terminal can also perform synchronization sequence detection to obtain the receiving time of the end position of the radio frame M in the first cell (for example, T1) . The terminal adds the first time value and the transmission delay to determine the second time value corresponding to the receiving time T1 at the end position of the radio frame M in the first cell, and the second time value is December 29, 2018 13:14:36 587ms623.25us.

With the clock synchronization method provided in the embodiments of the present application, the terminal can obtain relatively accurate transmission delay. In this way, the terminal performs clock synchronization according to the obtained relatively accurate transmission delay, which can reduce the clock synchronization error between the terminal and the first network device. For example, the terminal may receive the first information used to determine the transmission delay from the first network device. The first information may be that the first network device measures the distance between the first network device and the terminal by means of radar or wireless positioning, and the obtained distance or the distance between the first network device and the terminal determined according to the measured distance The transmission delay obtained in this way is more accurate than using TA to determine the transmission delay.

For example, take the terminal as an operating arm terminal. Assume that the distance between the operating arm terminal and the first network device is 100 meters, and the radius of the operating arm terminal's range of motion is 10 meters. That is to say, the distance between the operating arm terminal and the first network device is 90 meters to 110 meters, and the transmission delay is about 0.3us-0.36us by dividing the distance by the speed of light. According to actual measurement, when the distance between the operating arm terminal and the first network device is 90 meters to 110 meters, the transmission delay is 0.3 us to 0.4 us. Therefore, the error caused by the measurement of the transmission delay is about 0.1 us (0.4 us-0.36 us = 0.04 us, about 0.1 us). Using the method of calculating TA, combining with Table 1, taking SCS equal to 15kHz as an example, the error of the determined transmission delay reaches 0.78us.

Optionally, in order to make the terminal clock synchronization result more accurate, in some embodiments, the time accuracy of the transmission delay determined according to the foregoing first information may be less than or equal to the time accuracy of the foregoing first time value. For example, the time accuracy of the above first time value is 250 ns. Taking the first information as the transmission delay itself between the terminal and the first network device as an example, the time accuracy of the transmission delay sent by the first network device to the terminal may be less than or equal to 250ns. The smaller the time accuracy, the more accurate the result of terminal clock synchronization.

The terminal may be in a mobile state. As the terminal moves, the distance between the terminal and the first network device will change, and the transmission delay between the two will also change accordingly. Therefore, in some embodiments, the terminal may periodically obtain the above-mentioned first information, so as to periodically determine the transmission delay based on the first information, thereby performing clock synchronization, so as to further reduce the clock between the terminal and the first network device.的synchronization error.

Exemplarily, taking the first information delivered by the first network device to the terminal as an example, the first network device may periodically obtain the distance to the terminal, and periodically send the foregoing first information to the terminal. If the first information is the transmission delay itself between the terminal and the first network device, the first network device can measure the distance between the terminal and the first network device at regular intervals (such as 5 minutes, 30 minutes, etc.), and The terminal is notified of the transmission delay between the terminal and the first network device determined according to the measurement result. For another example, the first information is the distance itself between the terminal and the first network device, the first network device may measure the distance between the terminal and the first network device at regular intervals, and notify the terminal of the measurement result. In this way, the terminal can periodically obtain the first information for clock synchronization.

In some other embodiments, if the first information is issued by the first network device to the terminal, then the first network device may also send the first information to the terminal, and then communicate between the terminal and the first network device. The distance between them is monitored. If it is detected that the distance between the terminal and the first network device has changed, the first network device can re-issue the first information to the terminal so that the terminal can determine the transmission with the first network device according to the re-issued first information Time delay to synchronize clocks.

For example, take the example that the first information is the transmission delay itself between the terminal and the first network device. After the first network device has issued the transmission delay 1 to the terminal, it may monitor the distance between the terminal and the first network device. If it is obtained that the distance between the terminal and the first network device at the current moment has changed compared with the distance between the terminal and the first network device when the transmission delay is 1 time, the first network device may change the distance between the terminal and the first network device at the current moment. The distance between a network device determines the transmission delay 2 and informs the terminal of the transmission delay 2, and the terminal can perform clock synchronization according to the transmission delay 2. For another example, take the example that the first information is the distance itself between the terminal and the first network device. After the first network device sends a distance 1 (the distance between the terminal and the first network device) to the terminal, the distance between the terminal and the first network device can be monitored. If it is obtained that the distance 2 between the terminal and the first network device at the current moment has changed compared to the distance 1, the first network device can notify the terminal of the distance 2, and the terminal can determine the transmission delay according to the distance 2 for the clock Synchronize.

In other embodiments, the terminal can also monitor its own moving distance after acquiring the first information (for example, the terminal can measure itself through radar, wireless (such as Wifi) positioning, artificial intelligence analysis, image analysis, etc. If it is detected that the moving distance is greater than (or equal to) the distance threshold, it means that the distance between the terminal and the first network device may have changed, and the transmission delay of the two may have changed. At this time, the terminal may reacquire the first information, so as to determine the transmission delay according to the reacquired first information, so as to perform clock synchronization, so as to further reduce the clock synchronization error between the terminal and the first network device.

Exemplarily, it is taken as an example that the first information is delivered to the terminal by the first network device. After the terminal receives the first information issued by the first network device, the terminal can acquire the moving distance of the terminal from the moment when the first information is acquired to the current moment. If the acquired movement distance is greater than the distance threshold, the terminal may send first indication information to the first network device, where the first indication information is used to instruct the first network device to re-deliver the first information. If the first information is the transmission delay itself between the terminal and the first network device, the first network device may re-acquire the distance between the terminal and the first network device after receiving the first indication information, and will use the obtained The transmission delay between the terminal determined by the distance result and the first network device is notified to the terminal again, and the terminal can perform clock synchronization according to the newly acquired transmission delay. For another example, taking the first information as the distance between the terminal and the first network device itself, the first network device may re-acquire the distance between the terminal and the first network device after receiving the first indication information, and set The acquired distance is notified to the terminal, and the terminal can determine the transmission delay according to the re-acquired distance for clock synchronization.

In addition, in conjunction with the foregoing Table 1, it can be obtained that in the process of clock synchronization, the UE receiving frame timing will also introduce errors. For example, when SCS is equal to 15kHz, the error introduced by UE receiving frame timing is [12]*64*Tc, and when SCS is equal to 30kHz, the error introduced by UE receiving frame timing is [8]*64*Tc. That is to say, the terminal determines the frame boundary of the wireless frame, that is, there will be an error (the error may reach 390ns) at the receiving time of the frame boundary of the detected wireless frame. This part of the error also affects the accuracy of the clock synchronization between the terminal and the first network device. Will have an impact. In order to further reduce the clock synchronization error between the terminal and the first network device, further, the terminal determines the second time corresponding to the receiving moment of the frame boundary of the radio frame of the first cell according to the transmission delay and the first time value. Value, that is, before step 505, as shown in FIG. 6, the clock synchronization method may further include the following steps:

601. The terminal acquires the receiving moments of the frame boundaries of the radio frames of the M cells, the frame boundaries of the radio frames of the M cells are aligned, the M cells include the first cell, and M is an integer greater than or equal to 2.

602. The terminal updates the reception time of the frame boundary of the radio frame of the first cell according to the reception time of the frame boundary of the radio frame of the M cells.

Exemplarily, in order to reduce the error when the terminal determines the frame boundary of the wireless frame, the first network device may allocate multiple cells to the terminal, and the frame boundaries of the wireless frames of the multiple cells are aligned. To be precise, from the perspective of the first network device, the frame boundaries of the radio frames of the multiple cells are aligned. For example, as shown in Figure 7(a), the first network device allocates two cells to the terminal, namely cell 1 and cell 2, and from the perspective of the first network device, the radio frame of cell 1 The frame boundary is aligned with the frame boundary of the radio frame of cell 2, that is, the frame boundary of the radio frame M-2 of cell 1 and the radio frame M-2 of cell 2 is aligned, and the radio frame M-1 of cell 1 is aligned with that of cell 2. The frame boundaries of the radio frame M-1 are aligned, and the frame boundaries of the radio frame M of the cell 1 and the radio frame M of the cell 2 are aligned.

In addition, after the first network device allocates multiple cells to the terminal, it may send a notification message to the terminal. The notification message is used to inform the terminal that multiple cells are allocated to the terminal, and the frame boundaries of the radio frames of the multiple cells are aligned. It should be noted that, according to the agreement, when a network device sends a wireless frame, the frame boundary may be shifted forward or backward by 64Tc, but the network device cannot detect it. That is to say, the frame boundary alignment of the radio frames that allocate multiple cells to the terminal is not aligned in a strict sense. There is a deviation of less than 64Tc between the frame boundaries of different cells, and it can also be considered that the frame boundaries are aligned.

In this way, before the terminal performs clock synchronization according to the transmission delay and the first time value, it can perform frame boundary detection of radio frames on the multiple cells allocated by the first network device, that is, the terminal obtains the information of the multiple cells. The reception time of the frame boundary of the radio frame includes the reception time of the frame boundary of the radio frame of the first cell. Since the transmission paths of signals in different cells are not completely the same, the transmission delays of the terminal and the first network device in different cells are not necessarily the same. In this way, the radio frames of multiple cells obtained by the terminal are not necessarily the same. The receiving moment of the boundary is usually different. Therefore, after acquiring the frame boundaries of the radio frames of multiple cells, the terminal can update the frame boundaries of the radio frames of the first cell according to the acquired frame boundaries of the radio frames of the multiple cells. The receiving time is used to reduce the error in determining the frame boundary of the wireless frame, that is, to obtain a more accurate receiving time of the frame boundary of the wireless frame of the first cell. After determining the more accurate reception time of the frame boundary of the radio frame of the first cell, the terminal may perform the above step 505, that is, determine the reception of the frame boundary of the radio frame of the first cell according to the transmission delay and the first time value. The second time value corresponding to the time to complete clock synchronization.

It should be noted that the wireless frame mentioned here is the same wireless frame as the wireless frame indicated by the first time value in step 504. For example, the first time value in step 504 indicates the transmission time of the frame boundary of the radio frame M of the first cell (such as cell 1), then the radio frame here refers to the radio frame M, that is, the terminal obtains multiple The receiving time of the frame boundary of the radio frame M of the cell.

For example, in combination with the above step 504 and the example shown in (a) in FIG. 7, the frame boundary of the wireless frame is taken as the end position as an example. The terminal can acquire the reception time of the end position of the radio frame M in the cell 1 and the reception time of the end position of the radio frame M in the cell 2. As shown in (b) in FIG. 7, the receiving time at which the terminal acquires the end position of the radio frame M in cell 1 is T1, and the receiving time at the end position of the radio frame M in cell 2 is T2. If cell 1 is the first cell, the terminal can take the average value of T1 and T2 after acquiring the receiving time T1 of the end position of the radio frame M in cell 1 and the receiving time T2 of the end position of the radio frame M in cell 2 (T1 and T2 can also be weighted and averaged, and the weighted value corresponding to each cell can be configured by the first network device to the terminal), if the result obtained is T12, update T12 to the end position of the radio frame M in cell 1 Receive the moment. At this time, the terminal can determine the cell 1 according to the transmission delay (for example, the transmission delay is 300us) and the first time value (for example, the first time value: 13:14:36, December 29, 2018, 587ms323.25us) The second time value corresponding to the receiving time T12 at the end position of the wireless frame M, such as 587ms623.25us at 13:14:36 on December 29, 2018, to complete clock synchronization.

In particular, the description here assumes that the radio frame numbers of the multiple cells allocated by the first network device to the terminal are aligned. For example, in conjunction with the example in FIG. 7, the terminal obtains the frame boundary of the radio frame M of cell 1 At the same time, what is acquired is the receiving time of the frame boundary of the radio frame M of cell 2. In actual use, the wireless frame numbers of the multiple cells allocated by the first network device to the terminal may also be unaligned, and it is only necessary to ensure that the frame boundaries of the wireless frames of the multiple cells are aligned.

In this way, the terminal determines the frame boundary of the wireless frame by acquiring the receiving time of the frame boundary of the wireless frame of multiple cells, which can reduce the error when the terminal determines the frame boundary of the wireless frame, thereby further reducing the terminal and the first network device The synchronization error between the clocks.

In addition, further, as shown in FIG. 8, in step 504, the terminal acquiring the first time value may specifically include the following steps:

801. The terminal receives the time values indicating the sending moments of the frame boundaries of the radio frames from the M cells.

Wherein, the frame boundaries of the radio frames of the M cells are aligned, the M cells include the first cell, and M is an integer greater than or equal to 2.

802. The terminal determines a first time value according to the time values of the M cells.

Exemplarily, in order to reduce the error of the second time value corresponding to the receiving time of the radio frame determined by the terminal, the first network device may send the terminal indicating the radio frame of the cell through multiple cells allocated to the terminal. The time value of the sending moment of the frame boundary. That is to say, the foregoing step 503 may specifically be that the first network device transmits to the terminal a time value indicating the transmission time of the frame boundary of the radio frame of the cell through multiple cells allocated to the terminal. For example, the first network device sends a timing message to the terminal through multiple cells allocated to the terminal, and the timing message carries a time value indicating the transmission time of the frame boundary of the radio frame of the cell. The frame boundaries of the radio frames of the multiple cells are aligned, and the multiple cells include the first cell. In this way, the terminal can receive the time value of the transmission time indicating the frame boundary of the radio frame from multiple cells.

In addition, what the first network device indicates to the terminal may be the time value of the transmission time of the frame boundary of the same radio frame in multiple cells, or may not be the time value of the transmission time of the frame boundary of the same radio frame. If the indication is the time value of the transmission time of the frame boundary of the same radio frame, the terminal can average or weight the time values of multiple cells received (wherein, the weighted value corresponding to each cell can be the first network device Configured to the terminal) to determine the first time value. If the indication is not the time value of the sending moment of the frame boundary of the same radio frame, the terminal can calculate the same radio frame (the same radio frame refers to the same radio frame as the radio frame indicated by the first cell) ), and then determine the first time value based on the calculated time value and the received time value of the first cell indicating the transmission time of the frame boundary of the radio frame. The "same radio frame" refers to radio frames whose time boundaries are aligned when sent by the first network device. The radio frame numbers of the same radio frame in different cells may be the same or different.

For example, as shown in Figure 9(a), the first network device allocates two cells to the terminal, namely cell 1 and cell 2, and from the perspective of the first network device, the radio frame of cell 1 The frame boundary is aligned with the frame boundary of the radio frame of cell 2, that is, the frame boundary of the radio frame M-2 of cell 1 and the radio frame N-2 of cell 2 are aligned, and the radio frame M-1 of cell 1 is aligned with that of cell 2. The frame boundaries of the radio frame N-1 are aligned, and the frame boundaries of the radio frame M of the cell 1 and the radio frame N of the cell 2 are aligned. In addition, the radio frame M of cell 1 and the radio frame N of cell 2 are "the same radio frame", and their radio frame numbers are different. Take the end position of the frame boundary as an example. The first network device may send the time value 1 indicating the sending time of the end position of the radio frame M of the cell 1 to the terminal through cell 1 (for example, through the radio frame M-2 of cell 1), for example, the time value 1 is 2018 At 13:14:36 on December 29th, 587ms323.25us. The first network device may send a time value 2 indicating the sending time of the end position of the radio frame N of the cell 2 to the terminal through cell 2 (for example, through the radio frame N-1 of cell 2), for example, the time value 2 is 2018 At 13:14:36 on December 29, 587ms323.50us. Correspondingly, the terminal may receive the time value 1 of the cell 1 indicating the transmission time of the end position of the radio frame M, and the time value 2 of the cell 2 indicating the transmission time of the end position of the radio frame N. The terminal may average the received time value 1 and time value 2 to determine the first time value. If the result is a time value of 12: 13:14:36 on December 29, 2018, 587ms323.375us, the time value of 12 is the first time value.

Of course, after the terminal determines the first time value, it can determine the second time value corresponding to the receiving moment of the end position of the radio frame M in cell 1 according to the first time value and the transmission delay (for example, the transmission delay is 300us). For example, 587ms623.375us at 13:14:36 on December 29, 2018 to complete clock synchronization. It should be noted that, as shown in FIG. 9(b), the reception time of the end position of the radio frame M of cell 1 described here may be T1 as shown in FIG. 9(b), or it may be T12. T1 may be obtained after the terminal performs frame boundary detection on the wireless frame M indicated by the time value 1. T12 may be obtained by the terminal according to T1 and T2, and T2 is obtained after the terminal performs frame boundary detection on the radio frame N indicated by the time value 2. For the specific description of determining T12, reference may be made to the specific description of the corresponding content in the embodiment shown in FIG. 6, which will not be repeated here.

In this way, when the first network device notifies the terminal of the time value, the wireless frame of the time value sent has no time constraint, that is, the first network device can determine the wireless frame that notifies the terminal of the time value according to its own schedule. For example, in which wireless frame the load of the first network device is light, which wireless frame is used to notify the terminal of the time value.

In addition, as described in step 503 above, the first network device can send a timing message to the terminal in the form of broadcast or dedicated signaling through the cell allocated to the terminal to indicate the sending time of the frame boundary of the radio frame of the cell. The time value is notified to the terminal. In the case of a large number of terminals in the cell, the first network device usually sends the timing message in a broadcast manner, and in this manner, the timing message is sent periodically.

When the terminal has relatively high requirements for the accuracy of its own clock, due to clock drift of the terminal, the first network device may be required to send timing messages in a cell more frequently, that is, the terminal needs to read timing messages more frequently. Otherwise, in the second half of a timing message sending cycle, the clock maintained by the terminal itself may drift too much, exceeding the threshold, and failing to meet the requirements for clock accuracy. In this case, the first network device can achieve the goal by reducing the sending period of the timing message. However, this will occupy more wireless resources, and the sending cycle of timing messages is usually the sending cycle of reusing system information. If the sending cycle of system information (or called the system message window (SI window)) is reduced, it will cause other Unrelated terminals are also forced to read system information multiple times, which is obviously unnecessary.

In the embodiment of the present application, when the first network device allocates multiple cells to the terminal, the first network device can ensure that it is in the multiple cells if the sending period of the timing message in each cell remains unchanged. The sending period of the timing message of each cell is staggered, that is, the above step 503 may specifically include: the first network device sends an instruction wireless signal to the terminal through each of the multiple cells allocated to the terminal in different time windows. The time value of the transmission time of the frame boundary of the frame. In this way, the time window for the terminal to receive the time value of the transmission time indicating the frame boundary of the radio frame in different cells is different. That is to say, there is no need for the first network device to frequently send timing messages in a cell, and there is no need to reduce the transmission period of system messages. For the terminal, it reads the timing messages of multiple cells (the timing messages carry instructions The time value of the transmission time of the frame boundary of the wireless frame) can reduce the period of reading the timing message of the cell, and achieve the purpose of reading the timing message more frequently.

For example, as shown in FIG. 10, the first network device allocates two cells to the terminal, cell 1 and cell 2 respectively. The first network device sends a timing message to the terminal through cell 1 in time window 1. The timing message carries the time value of cell 1 indicating the sending moment of the frame boundary of the radio frame (time value 1 in Figure 10). ). The first network device sends a timing message to the terminal through cell 2 in time window 2. The timing message carries the time value of cell 2 indicating the sending moment of the frame boundary of the radio frame (time value (time) 2 in Figure 10). ). Among them, time window 1 and time window 2 are different and staggered.

Of course, the first network device may send second indication information to the terminal, and the second indication information is used to instruct the terminal to receive the indication radio frame of the cell in each of the multiple cells allocated to the terminal by the first network device. The time window of the time value of the sending moment of the frame boundary. Before step 801, the terminal may receive the second indication information from the first network device. In this way, the terminal can receive the time values of the multiple cells allocated to the terminal by the first network device according to the time window indicated by the second indication information. For example, in conjunction with FIG. 10, the first network device may send second indication information to the terminal. The second indication information is used to indicate the time window 1 for the terminal to receive the timing message in cell 1, and the time window for receiving the timing message in cell 2. 2. According to the time window 1 and time window 2 indicated by the second indication information, the terminal can receive timing messages in cell 1 and cell 2 respectively, so as to obtain the time value of cell 1 indicating the transmission time of the frame boundary of the radio frame and the cell 2 indicates the time value of the transmission time of the frame boundary of the radio frame. And because the time window 1 and the time window 2 are staggered, the terminal can read the timing messages more frequently, so that the clock accuracy after synchronization can meet the requirements of the terminal.

It should be noted that the multiple cells allocated to the terminal may be located in the same network device, or may be located in different network devices. If multiple cells are located in the same network device, the network device can internally ensure that the sending periods of the timing messages of each cell in the multiple cells are staggered.

If multiple cells are located in different network devices, the network devices can interact with each other to ensure that the sending periods of the timing messages of each cell in the multiple cells are staggered. For example, multiple cells are located in network device 1 and network device 2, respectively. The network device 1 can send to the network device 2 the time window of the time value of the transmission time indicating the frame boundary of the radio frame located in each cell of the network device 1. For example, the network device 1 informs the network device 2, and the network device 1 sends the time window of the timing message (Or called the timing period, the transmission period) is Y1 wireless frames. The time window for sending a timing message for a certain time (such as the first time) is from which wireless frame to which wireless frame, and the next time the wireless frame number is i The timing message is sent on the wireless frame. The network device 2 may also send to the network device 1 the time window indicating the time value of the transmission time of the frame boundary of the wireless frame to the network device 1 in each cell of the network device 2. For example, the network device 2 notifies the network device 1, and the network device 2 sends the timing message. The time window (or called the timing period, the transmission period) is Y2 wireless frames. The time window for sending a timing message for a certain time (such as the first time) is from which wireless frame to which wireless frame. The next time the wireless frame number is The timing message is sent on the radio frame of j. Through the interaction between network devices, it is finally possible to ensure that the sending period of the timing message of each cell among the multiple cells allocated to the terminal is staggered. In addition, in this process, the information exchanged between network devices can be notified to the terminal, and the network device may or may not read the message.

In some embodiments, according to the description in the embodiments shown in FIG. 6 and FIG. 8, it can be understood that the first network device can allocate multiple cells to the terminal to reduce the time when the terminal determines the frame boundary of the radio frame. And/or reduce the error when the terminal determines the time value corresponding to the receiving moment of the wireless frame, thereby reducing the error of clock synchronization. Obviously, the larger the number of cells allocated to the terminal, the smaller the error will be, the smaller the clock synchronization error will be, the higher the accuracy of the terminal clock will be. However, the greater the number of cells allocated to the terminal, the greater the amount of data processed by the terminal, and the greater the power consumption. Taking into account that different terminals and different services of the terminal have different requirements for clock accuracy, the first network device may allocate an appropriate number of cells to the terminal according to the instructions of the terminal. That is, the embodiment of the present application may further include: the terminal sends third instruction information to the first network device, and the third instruction information is used by the first network device to allocate a cell to the terminal. The first network device may receive the third indication information from the terminal, and allocate a suitable number of cells to the terminal according to the third indication information.

In some embodiments, the above-mentioned third indication information may be the terminal's requirement on the accuracy of the clock of the terminal. For example, the terminal may report to the first network device its error requirement for the determined receiving moment of the frame boundary of the wireless frame, for example, the error is within XXXXns. The first network device allocates an appropriate number of cells to the terminal according to the error requirement.

In other embodiments, the above-mentioned third indication information may be the identifier of the first service of the terminal or the quality of service (QoS) identifier of the first service. The first service of the terminal requires more precision on the clock of the terminal than other services of the terminal require on the clock of the terminal. For example, the terminal may report to the first network device the identifier of the service (that is, the first service) that requires the highest clock accuracy among all the services it is currently performing, or the QoS identifier of the first service. Correspondences between different service identifiers (or different QoS identifiers) and different cell numbers may be stored in the first network device. According to this correspondence, the first network device can allocate a suitable number of cells to the terminal. In addition, the terminal can also report one or more cell identities (such as frequency points) obtained by its own measurement to the first network device, such as carrying it in the third indication information and reporting it to the first network device. Of course, it can also be carried in Other instructions are reported to the first network device. In this way, the first network device can allocate an appropriate number of cells to the terminal according to the cell identification reported by the terminal and the terminal's clock accuracy requirements (or the identification of the first service or the QoS identification of the first service).

In some other embodiments, the first network device allocates a suitable number of cells to the terminal (for example, allocates N cells to the terminal, where N is an integer greater than or equal to 2), and can also configure a signal strength threshold to the terminal. The terminal uses the first network device to synchronize the clocks of the cells allocated to it. For example, when determining the frame boundary of the radio frame, it can first monitor the signal strength of these N cells. If one or a few of these N cells are If the signal strength of each cell is lower than the configured signal strength threshold, the terminal may not use these cells for clock synchronization. If these cells are not used to assist in determining the receiving time of the frame boundary of the radio frame, that is, the terminal may use M The cell (M is less than or equal to N) is used to assist in determining the receiving moment of the frame boundary of the radio frame. It should be noted that the signal strength threshold may be reference signal received power (RSRP), reference signal received quality (RSRQ), received signal strength indicator (RSSI) ) Any one or more of them. The signal strength threshold configured by the first network device for the terminal may be one or multiple. For example, configure the same signal strength threshold for cells of different frequency bands. For another example, different signal strength thresholds are configured for cells with different frequency bands, for example, a cell with a frequency band greater than 6 GHz is configured with a signal strength threshold, and a cell with a frequency band less than 6 GHz is configured with another signal strength threshold.

In some other embodiments, when the first network device allocates cells to the terminal, it may also allocate more cells than the requirements of the terminal. Exemplarily, the first network device determines that the number of cells that need to be allocated to the terminal is X according to the foregoing third indication information, but the first network device allocates N cells (N greater than or equal to X) for the terminal. For example, according to the terminal's requirements for clock accuracy, the first network device determines that only three cells are needed to meet the requirements of the terminal, but the first network device allocates five cells to the terminal. When the terminal is performing clock synchronization, such as determining the frame boundary of a radio frame, the five cells can be used to determine the frame boundary of the radio frame, or the three cells with the strongest signal can be selected for the frame boundary of the radio frame according to the signal strength. Of ok. Of course, the signal strengths of the three selected cells are all greater than the signal strength threshold.

In addition, it should be noted that, in the embodiment of the present application, the multiple (such as N) cells allocated by the first network device to the terminal may only be used for the terminal to perform frame boundary detection of radio frames and/or determine radio frame boundaries. The time value corresponding to the receiving moment is only used for clock synchronization, and not for other purposes, such as not being used for the terminal to perform carrier aggregation. Of course, it can also be used for the terminal to perform carrier aggregation, which is not specifically limited in the embodiment of the present application. Moreover, the multiple cells allocated to the terminal may be physically co-sited or not co-sited. It is only necessary to ensure that the frame boundaries of the radio frames of the multiple cells are aligned, that is, the time when the signal is sent is aligned. Of course, it is also possible that the difference between the frame boundaries of the radio frames of the multiple cells is smaller than [2]*64*Tc, which can also reduce the clock synchronization error between the terminal and the first network device.

It should be noted that the process of determining the frame boundary of the radio frame (i.e., step 601 and step 602), and the process of determining the time value corresponding to the sending moment of the frame boundary of the radio frame of the first cell (i.e., step 801 and step 802) ), and the foregoing process of determining the transmission delay between the terminal and the first network device, the three are not dependent on each other and can be performed independently. That is to say, in specific implementation, the TA method can be used to determine the transmission delay between the terminal and the first network device (for example, to obtain the TA, the transmission delay is equal to one-half of the TA), but the above steps 601 and Step 602 determines the frame boundary of the radio frame. Alternatively, the TA method may be used to determine the transmission delay between the terminal and the first network device, but the above steps 801 and 802 are used to determine the time value corresponding to the sending moment of the frame boundary of the wireless frame. The embodiments of the application do not make specific limitations here. Of course, the process described in the embodiments of this application can also be used at the same time to determine the transmission delay, determine the frame boundary of the wireless frame, and determine the time value corresponding to the transmission moment of the frame boundary of the wireless frame. In this way, the terminal and the first The clock synchronization error between network devices is smaller.

After the clock between the terminal and the first network device is synchronized, if the terminal needs to switch to the second network device, currently, the terminal is required to obtain the TA through a random access process before the TA can be used for data transmission with the second network device. In the embodiment of this application, the TA can be obtained without the terminal performing random access.

In some embodiments, further, as shown in FIG. 11, the method may further include the following steps:

1101. The first network device sends a handover request to the second network device.

Wherein, when the terminal is camped in a cell of the first network device (such as cell 1), it can measure the signal quality of a cell adjacent to cell 1, and can also carry the measurement result in a measurement report and report it to the first network equipment. After receiving the measurement report sent by the terminal, the first network device may send a handover request to the second network device if it determines that the signal quality of the second cell of the second network device indicated in the measurement report is good. The handover request is used to request the second network device, and the terminal will switch to the second cell of the second network device.

1102. The second network device sends a handover response to the first network device, where the handover response includes a third time value, and the third time value is used to indicate the sending moment of the subframe boundary of the second cell of the second network device.

After receiving the switching request sent by the first network device, the second network device may return a switching response to the first network device. In the embodiment of the present application, the handover response may carry a third time value used to indicate the sending moment of the subframe boundary of the second cell of the second network device. The second network device may notify the first network device of the precise time of the subframe boundary of the second cell (the target cell to which the terminal will be handed over). The subframe boundary can be the start position or the end position of the subframe. For example, take the subframe boundary as the starting position. The second network device may notify the first network device through the X2 interface that the time value of the start position of the subframe of the second cell of the second network device is 306ms 405us at 14:38:49 on December 29, 2018. Wherein, the third time value may be an explicit (or plaintext) time value, which is readable by the first network device, or an implicit time value, such as being carried in a container, that is, the first A network device is unreadable.

1103. The first network device sends a handover command to the terminal, and the handover command includes the foregoing third time value.

After receiving the third time value, the first network device may carry the third time value in the handover command and send it to the terminal.

1104. The terminal receives the third time value sent by the first network device.

1105. After switching to the above-mentioned second cell, the terminal obtains a fourth time value, where the fourth time value is used to indicate the receiving moment of the subframe boundary of the second cell.

1106. The terminal determines the transmission delay between the terminal and the second network device according to the third time value and the fourth time value.

The terminal may perform downlink synchronization with the second network device after switching to the second cell of the second network device. During the period of downlink synchronization, the internal clock of the terminal continues to run, and during this period of time, the clock drift of the second network device and the terminal may not be considered. The terminal can identify the subframe by detecting the synchronization sequence. In addition, corresponding to the clock maintained by itself, the terminal can obtain the time value (that is, the fourth time value) corresponding to the receiving time of the identified subframe boundary (such as the starting position) of the subframe is 14:00 on December 29, 2018 38 minutes 49 seconds 310ms705us.

Furthermore, according to the received third time value: 306ms405us at 14:38:49 on December 29, 2018, the terminal can infer the time value corresponding to the sending moment of the start position of the other subframes of the second cell (adjacent The interval between subframes is 1ms) respectively: 306ms405us at 14:38:49 on December 29, 2018, 307ms405us at 14:38:49 on December 29, 2018, and 14:38 on December 29, 2018 49 seconds 308ms405us, December 29, 2018 14:38:49 seconds 309ms405us, December 29, 2018 14:38:49 seconds 310ms405us, etc. The terminal selects the time value closest to the detected fourth time value from these time values, that is, "310ms405us at 14:38:49, December 29, 2018". The terminal can consider this time value as the time value corresponding to the sending moment of the subframe boundary (starting position) of the subframe detected by itself. It can be obtained that the time value corresponding to the sending moment of the starting position of the subframe is "December 29, 2018 14:38:49 310ms405us", and the time value of the receiving moment of the starting position of the subframe is "310ms705us at 14:38:49 on December 29, 2018". Since the clocks of the first network device and the terminal are accurately synchronized, the terminal can determine that the downlink transmission delay between the terminal and the second network device is 300 us.

Alternatively, the terminal can also obtain the possible transmission delay based on these time values. For example, if the terminal thinks that the time value corresponding to the sending time is "December 29, 2018 14:38:49, 310ms405us", according to the time value of the receiving time It is “310ms705us at 14:38:49, December 29, 2018” to determine that the downlink transmission delay is 300us; if the terminal thinks that the time value corresponding to the sending time is: “14:38:49, December 29, 2018 309ms405us”, then according to the time value of the receiving time as “310ms705us at 14:38:49 on December 29, 2018”, it can be determined that the downlink transmission delay is 1300us; if the terminal thinks that the time value corresponding to the sending time is “December 2018 14:38:49 on the 29th, 308ms405us", according to the time value of the receiving time is "310ms705us at 14:38:49 on December 29, 2018", it can be determined that the downlink transmission delay is 2300us; if the terminal thinks that the sending time corresponds The time value of “December 29, 2018 14:38:49 seconds 307ms405us”, according to the time value of the receiving time is “December 29, 2018 14:38:49 seconds 310ms705us”, it can be determined that the downlink transmission delay is 3300us; if the terminal thinks that the time value corresponding to the sending time is "306ms405us at 14:38:49 on December 29, 2018", the time value at the receiving time is "310ms705us at 14:38:49 on December 29, 2018" It can be determined that the downlink transmission delay is 4300us. In addition, according to other information, if the terminal knows that the transmission delay between the terminal and the second network device cannot be 1300us, 2300us, 3300us, or 4300us, the terminal can determine the time value corresponding to the transmission delay 300us, that is, "December 2018 14:38:49 on the 29th, 310ms405us" is the time value corresponding to the transmission time of the subframe boundary (starting position) of the subframe detected by itself. Therefore, it is determined that the transmission delay between the terminal and the second network device is 300 us.

1107. The terminal performs data transmission according to the transmission delay between the terminal and the second network device.

After the terminal obtains the downlink transmission delay, the downlink transmission delay is multiplied by 2 to obtain the TA, so that when the terminal has data to transmit, the TA can be used for data transmission.

In some other embodiments, further, as shown in FIG. 12, the method may further include the following steps:

1201. The first network device sends a handover request to the second network device.

1202. The second network device sends a handover response to the first network device.

1203. The first network device sends a handover command to the terminal.

1204. After switching to the second cell of the second network device, the terminal obtains the system frame number (SFN) of the second cell, and receives the fifth time value sent by the second network device, and the fifth time value It is used to indicate the transmission time of the frame boundary of the radio frame of the second cell.

As described in the embodiment shown in FIG. 11, when the first network device determines that the signal quality of the second cell of the second network device is good, the terminal can switch to the second cell of the second network device. Different from the embodiment shown in FIG. 11, after the terminal switches to the second cell, it can read the MIB message to obtain the SFN of the second cell, and receive the radio frame N sent by the second network device to indicate the second cell. The fifth time value of the sending moment of the frame boundary. For example, the second network device sends a timing message to the terminal, and the time value (that is, the fifth time value) of the sending time of the end position of the radio frame with "SFN=N" in the timing message is 14:38 on December 29, 2018 49 seconds 302ms405us". The timing message can be sent through broadcast or dedicated signaling, which is not specifically limited here.

1205. The terminal obtains a sixth time value according to the foregoing SFN, where the sixth time value is used to indicate the receiving moment of the frame boundary of the radio frame of the second cell.

The terminal can determine the receiving time of the frame boundary (such as the end position) of the wireless frame N by detecting the synchronization sequence, and determine that the time value corresponding to the receiving time (ie, the sixth time value) is "2018 302ms705us at 14:38:49 on December 29th

1206. The terminal determines the transmission delay between the terminal and the second network device according to the fifth time value and the sixth time value.

According to the above fifth time value "December 29, 2018 14:38:49 seconds 302ms 405us" and the sixth time value "December 29, 2018 14:38:49 seconds 302ms705us", the terminal can determine the terminal and the first The downlink transmission delay between the two network devices is 300 us.

1207. The terminal performs data transmission according to the transmission delay between the terminal and the second network device.

In this way, using the method shown in FIG. 11 or FIG. 12, the terminal does not need to perform random access after switching to the target cell (such as the second cell of the second network device). The subframe notified by the second network device The precise time of the sending moment of the boundary or the TA can be obtained by reading the timing message of the target cell, and then the data can be transmitted in the target cell.

The embodiments of the present application also provide a device for implementing any of the above methods. For example, a clock synchronization device is provided that includes units (or means) for implementing each step performed by the terminal in any of the above methods.

For example, the clock synchronization device may include: an obtaining unit, such as performing step 502 in the above method to obtain the first information, step 504 to obtain the first time value, step 601 to obtain the receiving time of frame boundaries of radio frames of M cells, step 1105 Get the fourth time value, etc.

The determining unit, such as performing step 505 in the above method, determines the second time value corresponding to the receiving moment of the frame boundary of the radio frame of the first cell according to the transmission delay and the first time value, and step 802 determines the second time value corresponding to the frame boundary of the radio frame of the first cell. The time value determines the first time value, and step 1106 determines the transmission delay between the terminal and the second network device.

The clock synchronization apparatus may further include: a sending unit, for example, performing an operation of sending the first instruction information to the first network device to instruct the first network device to re-issue the first information.

The updating unit, such as performing step 602, updates the receiving time of the frame boundary of the radio frame of the first cell according to the receiving time of the frame boundary of the radio frame of the M cells.

The receiving unit, for example, performs step 801 to receive the time value of the sending time indicating the frame boundary of the radio frame of the M cells, and step 1104 receives the third time value and so on.

The transmission unit, such as performing step 1107, performs data transmission according to the transmission delay between the clock synchronization device and the second network device.

For another example, another clock synchronization device is also provided, including units (or means) for implementing each step performed by the network device in any of the above methods. Such as the first network device and the second network device described above.

For example: the clock synchronization device may include: a sending unit, such as performing step 501 in the above method to send the first information to the terminal, and step 503 sends the terminal a time value indicating the sending time of the frame boundary of the radio frame through the cell allocated for the terminal. , Step 1101, Step 1201 send a switching request to the second network device, Step 1103, Step 1203 send a switching command to the terminal, etc.

The clock synchronization device may further include: an acquiring unit, such as performing an operation of acquiring the distance between the terminal and the clock synchronization device. The receiving unit, for example, performs an operation of receiving the third instruction information from the terminal. The allocation unit, for example, performs the operation of allocating an appropriate number of cells to the terminal.

It should be understood that the division of the units in the above device is only a division of logical functions, and may be fully or partially integrated into one physical entity in actual implementation, or may be physically separated. In addition, the units in the device can all be implemented in the form of software called by processing elements; they can also be implemented in the form of hardware; part of the units can also be implemented in the form of software called by the processing elements, and some of the units can be implemented in the form of hardware.

For example, each unit can be a separately set up processing element, or it can be integrated in a certain chip of the device for implementation. In addition, it can also be stored in the memory in the form of a program, which is called and executed by a certain processing element of the device. Features. In addition, all or part of these units can be integrated together or implemented independently. The processing element described here can also become a processor, which can be an integrated circuit with signal processing capabilities. In the implementation process, each step of the above method or each of the above units may be implemented by an integrated logic circuit of hardware in a processor element or implemented in a form of being called by software through a processing element.

In an example, the unit in any of the above devices may be one or more integrated circuits configured to implement the above method, for example: one or more application specific integrated circuits (ASIC), or, one or Multiple microprocessors (digital singnal processors, DSP), or, one or more field programmable gate arrays (FPGA), or a combination of at least two of these integrated circuits.

For another example, when the unit in the device can be implemented in the form of a processing element scheduler, the processing element can be a general-purpose processor, such as a central processing unit (CPU) or other processors that can call programs. For another example, these units can be integrated together and implemented in the form of a system-on-a-chip (SOC).

The above receiving unit is an interface circuit of the device for receiving signals from other devices. For example, when the device is implemented as a chip, the receiving unit is an interface circuit used by the chip to receive signals from other chips or devices. The above unit for sending is an interface circuit of the device for sending signals to other devices. For example, when the device is implemented as a chip, the sending unit is an interface circuit used by the chip to send signals to other chips or devices.

Please refer to FIG. 13, which is a schematic structural diagram of a network device provided by an embodiment of this application. It may be the network device in the above embodiment, and is used to implement the operation of the network device in the above embodiment.

As shown in FIG. 13, the network equipment includes: an antenna 1301, a radio frequency device 1302, and a baseband device 1303. The antenna 1301 is connected to the radio frequency device 1302. In the uplink direction, the radio frequency device 1302 receives the information sent by the terminal through the antenna 1301, and sends the information sent by the terminal to the baseband device 1303 for processing. In the downlink direction, the baseband device 1303 processes the terminal information and sends it to the radio frequency device 1302, and the radio frequency device 1302 processes the terminal information and sends it to the terminal via the antenna 1301.

The baseband device 1303 may include one or more processing elements 1303-1, for example, a main control CPU and other integrated circuits. In addition, the baseband device 1303 may also include a storage element 1303-2 and an interface 1303-3. The storage element 1303-2 is used to store programs and data; the interface 1303-3 is used to exchange information with the radio frequency device 1302. The interface is, for example, a universal Common public radio interface (CPRI). The above apparatus for network equipment may be located in the baseband apparatus 1303. For example, the above apparatus for network equipment may be a chip on the baseband apparatus 1303. The chip includes at least one processing element and an interface circuit, wherein the processing element is used to execute the above network For each step of any method executed by the device, the interface circuit is used to communicate with other devices. In one implementation, the unit for the network device to implement each step in the above method can be implemented in the form of a processing element scheduler. For example, the device for the network device includes a processing element and a storage element, and the processing element calls the program stored by the storage element to Perform the method performed by the network device in the above method embodiment. The storage element may be a storage element with the processing element on the same chip, that is, an on-chip storage element, or a storage element on a different chip from the processing element, that is, an off-chip storage element.

In another implementation, the unit of the network device that implements each step in the above method may be configured as one or more processing elements, and these processing elements are arranged on the baseband device. The processing elements here may be integrated circuits, such as one Or multiple ASICs, or, one or more DSPs, or, one or more FPGAs, or a combination of these types of integrated circuits. These integrated circuits can be integrated together to form a chip.

The units for the network equipment to implement the steps in the above method can be integrated together and implemented in the form of a system-on-a-chip (SOC). For example, the baseband device 1303 includes the SOC chip for implementing the above method. At least one processing element and storage element can be integrated in the chip, and the processing element can call the stored program of the storage element to implement the method executed by the above network device; or, at least one integrated circuit can be integrated in the chip to implement the above network The method executed by the device; or, it can be combined with the above implementations. The functions of some units are implemented in the form of calling programs by processing elements, and the functions of some units are implemented in the form of integrated circuits.

It can be seen that the above apparatus for a network device may include at least one processing element and an interface circuit, wherein at least one processing element is used to execute any method executed by the network device provided in the above method embodiments. The processing element can execute part or all of the steps executed by the network device in the first way: calling the program stored in the storage element; or in the second way: combining instructions through the integrated logic circuit of the hardware in the processor element Part or all of the steps performed by the network device are executed in the method; of course, part or all of the steps executed by the network device can be executed in combination with the first method and the second method.

The processing elements here are the same as those described above, and may be a general-purpose processor, such as a CPU, or one or more integrated circuits configured to implement the above methods, such as: one or more ASICs, or, one or more micro-processing DSP, or, one or more FPGAs, etc., or a combination of at least two of these integrated circuit forms.

The storage element may be a memory or a collective term for multiple storage elements.

Please refer to FIG. 14, which is a schematic structural diagram of a terminal provided in an embodiment of the application. It may be the terminal in the above embodiment, and is used to implement the operation of the terminal in the above embodiment.

As shown in FIG. 14, the terminal includes: an antenna 1401, a radio frequency part 1402, and a signal processing part 1403. The antenna 1401 is connected to the radio frequency part 1402. In the downlink direction, the radio frequency part 1402 receives the information sent by the network device through the antenna 1401, and sends the information sent by the network device to the signal processing part 1403 for processing. In the upstream direction, the signal processing part 1403 processes the terminal information and sends it to the radio frequency part 1402, and the radio frequency part 1402 processes the terminal information and sends it to the network device via the antenna 1401.

The signal processing part 1403 may include a modem subsystem, which is used to process data at various communication protocol layers; it may also include a central processing subsystem, which is used to process terminal operating systems and application layers; in addition, it may also include Other subsystems, such as multimedia subsystem, peripheral subsystem, etc., where the multimedia subsystem is used to control the terminal camera, screen display, etc., and the peripheral subsystem is used to realize the connection with other devices. The modem subsystem can be a separate chip. Optionally, the above apparatus for the terminal may be located in the modem subsystem.

The modem subsystem may include one or more processing elements 1403-1, for example, including a main control CPU and other integrated circuits.

In addition, the modem subsystem may also include a storage element 1403-2 and an interface circuit 1403-3. The storage element 1403-2 is used to store data and programs, but the program used to execute the method executed by the terminal in the above method may not be stored in the storage element 1403-2, but is stored outside the modem subsystem. In the memory, the modem subsystem is loaded and used when in use. The interface circuit 1403-3 is used to communicate with other subsystems. The above device for the terminal may be located in the modem subsystem, the modem subsystem may be implemented by a chip, the chip includes at least one processing element and an interface circuit, wherein the processing element is used to execute any of the methods performed by the above terminal In each step, the interface circuit is used to communicate with other devices.

In one implementation, the unit for the terminal to implement each step in the above method can be implemented in the form of a processing element scheduler. For example, the device for the terminal includes a processing element and a storage element, and the processing element calls the program stored by the storage element to execute the above The method executed by the terminal in the method embodiment. The storage element may be a storage element whose processing element is on the same chip, that is, an on-chip storage element.

In another implementation, the program for executing the method executed by the terminal in the above method may be a storage element on a different chip from the processing element, that is, an off-chip storage element. At this time, the processing element calls or loads the program from the off-chip storage element on the on-chip storage element to call and execute the method executed by the terminal in the above method embodiment.

In yet another implementation, the terminal that implements each step in the above method may be configured as one or more processing elements, and these processing elements are provided on the modem subsystem, where the processing elements may be integrated circuits, such as : One or more ASICs, or, one or more DSPs, or, one or more FPGAs, or a combination of these types of integrated circuits. These integrated circuits can be integrated together to form a chip.

The units for the terminal to implement each step in the above method can be integrated together and implemented in the form of an SOC, and the SOC chip is used to implement the above method. At least one processing element and a storage element can be integrated in the chip, and the above terminal execution method can be realized by the processing element calling the stored program of the storage element; or, at least one integrated circuit can be integrated in the chip for realizing the above terminal execution Or, it can be combined with the above implementations. The functions of some units are implemented in the form of calling programs by processing elements, and the functions of some units are implemented in the form of integrated circuits.

It can be seen that the above apparatus for a terminal may include at least one processing element and an interface circuit, wherein at least one processing element is used to execute any of the methods performed by the terminal provided in the above method embodiments. The processing element can execute part or all of the steps executed by the terminal in the first way: calling the program stored in the storage element; or in the second way: combining instructions through the integrated logic circuit of the hardware in the processor element Part or all of the steps executed by the terminal are executed in a manner; of course, part or all of the steps executed by the terminal may also be executed in combination with the first manner and the second manner.

Through the description of the above embodiments, those skilled in the art can clearly understand that for the convenience and brevity of the description, only the division of the above-mentioned functional modules is used as an example. In practical applications, the above-mentioned functions can be allocated according to needs. It is completed by different functional modules, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above.

In the several embodiments provided in this application, it should be understood that the disclosed device and method may be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the modules or units is only a logical function division. In actual implementation, there may be other division methods, for example, multiple units or components may be It can be combined or integrated into another device, or some features can be omitted or not implemented. In addition, the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may be in electrical, mechanical or other forms.

The units described as separate parts may or may not be physically separate, and the parts displayed as units may be one physical unit or multiple physical units, that is, they may be located in one place, or they may be distributed to multiple different places. . Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.

In addition, the functional units in the various embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units may be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or software functional unit.

If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solutions of the embodiments of the present application are essentially or the part that contributes to the existing technology, or all or part of the technical solutions can be embodied in the form of software products, which are stored in a storage medium. It includes several instructions to make a device (may be a single-chip microcomputer, a chip, etc.) or a processor (processor) execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage media include: U disk, mobile hard disk, ROM, RAM, magnetic disk or optical disk and other media that can store program codes.

The above are only specific implementations of this application, but the protection scope of this application is not limited to this. Any changes or substitutions within the technical scope disclosed in this application shall be covered by the protection scope of this application . Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

A clock synchronization method is characterized in that it includes:

The terminal obtains first information, where the first information is used to determine the transmission delay between the terminal and the first network device;

Acquiring, by the terminal, a first time value, where the first time value is used to indicate the sending moment of the frame boundary of the radio frame of the first cell of the first network device;

The terminal determines, according to the transmission delay and the first time value, a second time value corresponding to the receiving moment of the frame boundary of the radio frame of the first cell.
The method according to claim 1, wherein the first information is information for indicating the transmission delay.
The method according to claim 1, wherein the first information is information used to indicate the distance between the terminal and the first network device;

The method also includes:

The terminal obtains the transmission delay according to the distance between the terminal and the first network device.
The method according to any one of claims 1-3, wherein the method further comprises:

Acquiring, by the terminal, the movement distance of the terminal from the moment when the first information is acquired to the current moment;

When the moving distance is greater than the distance threshold, the terminal sends first indication information to the first network device, where the first indication information is used to instruct the first network device to re-deliver the first information.
The method according to any one of claims 1 to 4, wherein the method further comprises:

The terminal acquires the receiving moments of the frame boundaries of the radio frames of M cells, the frame boundaries of the radio frames of the M cells are aligned, the M cells include the first cell, and M is An integer greater than or equal to 2;

The terminal updates the reception time of the frame boundary of the radio frame of the first cell according to the reception time of the frame boundary of the radio frames of the M cells.
The method according to any one of claims 1-5, wherein the obtaining the first time value by the terminal comprises:

Receiving, by the terminal, the time values indicating the transmission moments of the frame boundaries of the radio frames of M cells, the frame boundaries of the radio frames of the M cells are aligned, and the M cells include the first cell, The M is an integer greater than or equal to 2;

The terminal determines the first time value according to the time values of the M cells.
The method according to claim 6, characterized in that, in the M cells, the terminal receives different time windows indicating the time value of the transmission time of the frame boundary of the radio frame from different cells;

The method also includes:

The terminal receives second indication information from the first network device, where the second indication information is used to indicate that in each of the N cells, the sending of the frame boundary indicating the radio frame of the cell is received A time window of the time value of the moment, the N cells include the M cells;

The receiving, by the terminal, the time values indicating the transmission moments of the frame boundaries of the radio frames from M cells includes:

The terminal receives the time values of the M cells according to the time window indicated by the second indication information.
The method according to any one of claims 5-7, wherein the method further comprises:

The terminal sends third indication information to the first network device, where the third indication information is used by the first network device to allocate cells to the terminal, and the cells allocated to the terminal include the M cells;

Wherein, the third indication information is the accuracy requirement of the terminal for the clock of the terminal; or, the third indication information is the identification of the first service of the terminal or the quality of service QoS of the first service Identifies that the first service of the terminal requires more precision on the clock of the terminal than other services of the terminal require on the clock of the terminal.
The method according to any one of claims 1-8, wherein the method further comprises:

Receiving, by the terminal, a third time value sent by the first network device, where the third time value is used to indicate the sending moment of the subframe boundary of the second cell of the second network device;

After switching to the second cell, the terminal obtains a fourth time value, where the fourth time value is used to indicate the receiving moment of the subframe boundary of the second cell;

Determining, by the terminal, the transmission delay between the terminal and the second network device according to the third time value and the fourth time value;

The terminal performs data transmission according to the transmission delay between the terminal and the second network device.
The method according to any one of claims 1-8, wherein the method further comprises:

After switching to the second cell of the second network device, the terminal obtains the system frame number SFN of the second cell, and receives the fifth time value sent by the second network device. The fifth time value is used At the sending moment indicating the frame boundary of the radio frame of the second cell;

Acquiring, by the terminal, a sixth time value according to the SFN, where the sixth time value is used to indicate the receiving moment of the frame boundary of the radio frame of the second cell;

Determining, by the terminal, the transmission delay between the terminal and the second network device according to the fifth time value and the sixth time value;

The terminal performs data transmission according to the transmission delay between the terminal and the second network device.
A clock synchronization device is characterized by comprising:

The first acquiring unit is configured to acquire first information and a first time value, where the first information is used to determine the transmission delay between the clock synchronization apparatus and the first network device, and the first time value is used to indicate The sending moment of the frame boundary of the radio frame of the first cell of the first network device;

The determining unit is configured to determine a second time value corresponding to the receiving moment of the frame boundary of the radio frame of the first cell according to the transmission delay and the first time value.
The clock synchronization device according to claim 11, wherein the first information is information for indicating the transmission delay.
The clock synchronization device according to claim 11, wherein the first information is information used to indicate the distance between the clock synchronization device and the first network device;

The first obtaining unit is further configured to obtain the transmission delay according to the distance between the clock synchronization apparatus and the first network device.
The clock synchronization device according to any one of claims 11-13, wherein the clock synchronization device further comprises: a second acquiring unit and a sending unit;

The second acquiring unit is configured to acquire the moving distance of the clock synchronization device from the moment when the first information is acquired to the current moment;

The sending unit is configured to send first instruction information to the first network device when the moving distance is greater than a distance threshold, where the first instruction information is used to instruct the first network device to reissue the first network device One information.
The clock synchronization device according to any one of claims 11-14, wherein the clock synchronization device further comprises: an update unit;

The first obtaining unit is further configured to obtain receiving moments of the frame boundaries of the radio frames of the M cells, the frame boundaries of the radio frames of the M cells are aligned, and the M cells include the first In a cell, the M is an integer greater than or equal to 2;

The updating unit is configured to update the receiving time of the frame boundary of the radio frame of the first cell according to the receiving time of the frame boundary of the radio frames of the M cells.
The clock synchronization device according to any one of claims 11-15, wherein the clock synchronization device further comprises: a receiving unit;

The receiving unit is configured to receive time values indicating the transmission moments of the frame boundaries of the radio frames of M cells, the frame boundaries of the radio frames of the M cells are aligned, and the M cells include the In the first cell, the M is an integer greater than or equal to 2;

The first acquiring unit is specifically configured to determine the first time value according to the time values of the M cells.
The clock synchronization device according to claim 16, wherein, in the M cells, the clock synchronization device receives different time windows indicating the time value of the transmission time of the frame boundary of the radio frame from different cells. ；

The receiving unit is further configured to receive second indication information from the first network device, where the second indication information is used to indicate that all the indication radio frames of the cell are received in each of the N cells. The time window of the time value of the sending moment of the frame boundary, the N cells include the M cells;

The receiving unit is specifically configured to receive the time values of the M cells according to the time window indicated by the second indication information.
The clock synchronization device according to any one of claims 15-17, wherein the clock synchronization device further comprises: a sending unit;

The sending unit is configured to send third indication information to the first network device, where the third indication information is used by the first network device to allocate a cell to the clock synchronization apparatus, and the clock synchronization is The cells allocated by the device include the M cells;

Wherein, the third indication information is the accuracy requirement of the clock synchronization apparatus for the clock of the clock synchronization apparatus; or, the third indication information is the identifier of the first service of the clock synchronization apparatus or the first service The quality of service QoS identifier of a service, the first service of the clock synchronization device requires more precision for the clock of the clock synchronization device than other services of the clock synchronization device require for the clock of the clock synchronization device.
The clock synchronization device according to any one of claims 11-18, wherein the clock synchronization device further comprises: a receiving unit and a transmission unit;

The receiving unit is configured to receive a third time value sent by the first network device, where the third time value is used to indicate the sending moment of the subframe boundary of the second cell of the second network device;

The second acquiring unit is further configured to acquire a fourth time value after switching to the second cell, where the fourth time value is used to indicate the receiving moment of the subframe boundary of the second cell;

The determining unit is further configured to determine the transmission delay between the clock synchronization apparatus and the second network device according to the third time value and the fourth time value;

The transmission unit is configured to perform data transmission according to the transmission delay between the clock synchronization device and the second network device.
The clock synchronization device according to any one of claims 11-18, wherein the clock synchronization device further comprises: a transmission unit;

The first obtaining unit is further configured to obtain the system frame number SFN of the second cell after switching to the second cell of the second network device, and receive the fifth time value sent by the second network device, The fifth time value is used to indicate the sending moment of the frame boundary of the radio frame of the second cell;

The second acquiring unit is further configured to acquire a sixth time value according to the SFN, where the sixth time value is used to indicate the receiving moment of the frame boundary of the radio frame of the second cell;

The determining unit is further configured to determine the transmission delay between the clock synchronization apparatus and the second network device according to the fifth time value and the sixth time value;

The transmission unit is configured to perform data transmission according to the transmission delay between the clock synchronization device and the second network device.
A clock synchronization device, characterized by comprising: a processor and an interface circuit, the processor is used to communicate with a network device through the interface circuit, and execute the method according to any one of claims 1 to 10.
A clock synchronization device, characterized by comprising a processor, which is configured to be connected to a memory and call a program stored in the memory to execute the method according to any one of claims 1 to 10.
A terminal, characterized by comprising the clock synchronization device according to any one of claims 11 to 20.
A computer-readable storage medium, characterized by comprising: computer software instructions;

When the computer software instruction runs in a clock synchronization device or a chip built in the clock synchronization device, the clock synchronization device is caused to execute the method according to any one of claims 1 to 10.