CN117202336A

CN117202336A - Time synchronization method, communication device and communication system

Info

Publication number: CN117202336A
Application number: CN202210613427.3A
Authority: CN
Inventors: 臧昕; 周润泽; 王远
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2022-05-31
Filing date: 2022-05-31
Publication date: 2023-12-08
Also published as: WO2023231465A1

Abstract

The embodiment of the application provides a time synchronization method, a communication device and a communication system. The method comprises the following steps: the terminal equipment receives time setting information from the access network equipment; and when the terminal equipment does not receive new time setting information from the access network equipment within the set time length, the terminal equipment performs time synchronization according to the current time of the terminal equipment, the receiving time of the time setting information and the time setting information. According to the scheme, when the access network equipment cannot send new time setting information to the terminal equipment or the access network equipment cannot timely send the new time setting information to the terminal equipment, the terminal equipment can realize accurate time synchronization between the terminal equipment and the access network equipment according to the time setting information received from the access network equipment before, and the communication capability of the terminal equipment is improved.

Description

Time synchronization method, communication device and communication system

Technical Field

The present application relates to the field of communications technologies, and in particular, to a time synchronization method, a communications device, and a communications system.

Background

To ensure proper communication between the terminal device and other devices, it is generally necessary to time synchronize the terminal device. The current synchronization method is that a terminal device receives a system information block (system information block, SIB) message broadcast by an access network device, the SIB message carries time synchronization information of the access network device, the terminal device acquires the time synchronization information from the SIB message, and performs time synchronization with the access network device according to the time synchronization information.

According to the scheme, the terminal equipment is dependent on the time service of the access network equipment, when the clock source on the access network equipment fails or the time service frequency of the access network equipment is low, the terminal equipment cannot or cannot timely receive the time service information, further accurate time synchronization between the terminal equipment and the access network equipment cannot be maintained, and the communication capacity of the terminal equipment is reduced.

Disclosure of Invention

The embodiment of the application provides a time synchronization method, a communication device and a communication system, which are used for realizing time synchronization between terminal equipment and access network equipment.

In a first aspect, embodiments of the present application provide a time synchronization method, which may be performed by a terminal device or a module (e.g., a chip) in the terminal device. Taking the terminal equipment to execute the method as an example, the method comprises the following steps: the terminal equipment receives time setting information from the access network equipment; the terminal device performs time synchronization according to the current time of the terminal device, the receiving time of the pair time information and the pair time information.

According to the scheme, the terminal equipment can realize accurate time synchronization between the terminal equipment and the access network equipment according to the time synchronization information received from the access network equipment before, and the terminal equipment does not depend on the access network equipment to provide the time synchronization information in time, so that when the access network equipment cannot send new time synchronization information to the terminal equipment or the access network equipment cannot send the new time synchronization information to the terminal equipment in time, the terminal equipment can finish time synchronization, and the communication capability of the terminal equipment is improved.

In a possible implementation method, a terminal device performs time synchronization according to a current time of the terminal device, a receiving time of the pair of time information, and the pair of time information, including: when the preset condition is met, the terminal equipment performs time synchronization according to the current time of the terminal equipment, the receiving time of the time setting information and the time setting information; wherein, the preset conditions are as follows: the terminal equipment does not receive new time setting information from the access network equipment within a set time length; or the terminal equipment receives the first indication information and the new time setting information from the access network equipment within the set time length, wherein the first indication information indicates that the new time setting information does not meet the time setting precision requirement of the terminal equipment.

According to the scheme, when the terminal equipment does not receive new time setting information from the access network equipment within the set time length; or the terminal equipment receives the indication information and the new time setting information from the access network equipment within the set time length, the indication information indicates that the new time setting information does not meet the time setting precision requirement of the terminal equipment, and the terminal equipment can realize accurate time synchronization between the terminal equipment and the access network equipment according to the time setting information received from the access network equipment before, thereby being beneficial to improving the communication capability of the terminal equipment.

In a possible implementation method, after the terminal device receives the pair time information from the access network device, the terminal device stores the receiving time of the pair time information and the pair time information.

According to the scheme, the terminal equipment stores the time setting information from the access network equipment, so that when the terminal equipment cannot receive new time setting information from the access network equipment within the time duration, the terminal equipment can acquire the stored time setting information and the receiving time of the time setting information, and time synchronization is carried out according to the time setting information and the receiving time of the time setting information, thereby being beneficial to realizing accurate time synchronization between the terminal equipment and the access network equipment and further being beneficial to improving the communication capability of the terminal equipment.

In a possible implementation method, the time synchronization is performed by the terminal device according to the current time of the terminal device, the receiving time of the pair of time information, and the pair of time information, including: the terminal equipment determines the difference value between the current time of the terminal equipment and the receiving time of the pair time information; the terminal equipment determines the synchronous time according to the difference value and the time setting information; and the terminal equipment performs time synchronization according to the synchronization time.

In a possible implementation method, the pair of time information includes a clock frequency ratio and a clock deviation, the clock frequency ratio represents a clock frequency ratio between the terminal device and the access network device, and the clock deviation represents a clock deviation between the terminal device and the access network device; the terminal device determines a synchronization time according to the difference value and the pair of time information, and the method comprises the following steps: the terminal equipment determines the ratio of the difference value to the clock frequency ratio; the terminal device determines the synchronization time according to the ratio, the clock deviation and the time of reception of the pair of time information.

According to the scheme, the terminal equipment performs time synchronization by combining the clock frequency ratio and the clock deviation, and accurate time synchronization is facilitated.

In one possible implementation method, the pair of time information includes a clock frequency ratio, a transmission delay and a sending time of the pair of time information, where the clock frequency ratio indicates a clock frequency ratio between the terminal device and the access network device, and the transmission delay indicates a transmission delay between the terminal device and the access network device; the terminal device determines a synchronization time according to the difference value and the pair of time information, and the method comprises the following steps: the terminal equipment determines the ratio of the difference value to the clock frequency ratio; and the terminal equipment determines the synchronous time according to the ratio, the transmission delay and the sending time of the time synchronization information.

According to the scheme, the terminal equipment performs time synchronization by combining the clock frequency ratio and the transmission delay, and accurate time synchronization is facilitated.

In one possible implementation method, the pair of time information includes a clock deviation change rate, a clock frequency ratio and a clock deviation, the clock deviation change rate represents a time-dependent change amount of the clock deviation, the clock frequency ratio represents a clock frequency ratio between the terminal device and the access network device, and the clock deviation represents a clock deviation between the terminal device and the access network device; the terminal device determines a synchronization time according to the difference value and the pair of time information, and the method comprises the following steps: the terminal equipment determines the product of the clock deviation change rate and the difference value, and determines the ratio of the product to the clock frequency ratio; the terminal device determines the synchronization time according to the ratio, the clock bias and the current time of the terminal device.

According to the scheme, the terminal equipment performs time synchronization by combining the clock frequency ratio, the clock deviation and the clock deviation change rate, and accurate time synchronization is facilitated.

In one possible implementation method, the terminal device receives the set duration from the access network device.

In one possible implementation, the set duration is preset.

In a possible implementation method, the terminal device sends a time synchronization request message, where the time synchronization request message includes identification information of the terminal device and second indication information, and the second indication information indicates that a time synchronization service is provided for the terminal device.

In a possible implementation method, the terminal device receives information for indicating to turn on the time tick function.

According to the scheme, the terminal equipment starts the time setting function according to the information for indicating to start the time setting function, so that when the terminal equipment does not receive new time setting information from the access network equipment within the set time length, the terminal equipment performs time synchronization according to the current time of the terminal equipment, the receiving time of the time setting information and the time setting information. The scheme helps the terminal equipment to perform time synchronization according to the correct method.

In a possible implementation method, the pair of time information includes a transmission delay and a sending time of the pair of time information, where the transmission delay represents a transmission delay between the terminal device and the access network device; the terminal device performs time synchronization according to the transmission delay and the sending time of the time synchronization information before performing time synchronization according to the current time of the terminal device, the receiving time of the time synchronization information and the time synchronization information.

In a second aspect, embodiments of the present application provide a time synchronization method, which may be performed by an access network device or a module (e.g., a chip) in the access network device. Taking an access network device as an example, the method includes: the access network equipment determines time setting information, wherein the time setting information comprises a clock frequency ratio which represents the clock frequency ratio between the terminal equipment and the access network equipment; the access network device sends the time synchronization information to the terminal device, and the time synchronization information is used for local time synchronization of the terminal device.

According to the scheme, the access network equipment sends the time setting information to the terminal equipment, so that when the access network equipment cannot send new time setting information to the terminal equipment afterwards or the access network equipment cannot timely send new time setting information to the terminal equipment, the terminal equipment can realize accurate time synchronization between the terminal equipment and the access network equipment according to the time setting information received from the access network equipment before, and the communication capability of the terminal equipment is improved.

In a possible implementation, the pair of time information further comprises a clock offset, the clock offset representing a clock offset between the terminal device and the access network device.

In a possible implementation method, the pair of time information further includes a transmission delay and a sending time of the pair of time information, where the transmission delay represents a transmission delay between the terminal device and the access network device.

In a possible implementation method, the pair of time information further includes a clock bias change rate and a clock bias, the clock bias change rate represents a time-dependent change amount of the clock bias, and the clock bias represents a clock bias between the terminal device and the access network device.

In a possible implementation method, the access network device determines a first clock bias at a first time and determines a second clock bias at a second time; the access network device determines the clock deviation change rate according to a first difference value between the second clock deviation and the first clock deviation and a second difference value between the second time and the first time.

In a possible implementation method, before the access network device determines the time setting information, the access network device receives indication information, where the indication information indicates to provide a time setting service for the terminal device.

In a third aspect, embodiments of the present application provide a time synchronization method, which may be performed by a clock management network element or a module (e.g., a chip) in the clock management network element. Taking the clock management network element as an example, the method comprises the following steps: the clock management network element receives a time synchronization request message, wherein the time synchronization request message comprises identification information and indication information of terminal equipment, and the indication information indicates that time synchronization service is provided for the terminal equipment; the clock management network element selects an access network device for providing time setting service for the terminal device; the clock management network element sends a notification message to the policy control network element, where the notification message includes identification information of the terminal device, identification information of the access network device, and the indication information.

According to the scheme, after the clock management network element receives the time setting request message, the access network equipment providing time setting service for the terminal equipment is selected, and the access network equipment is instructed to provide time setting service for the terminal equipment, so that accurate time synchronization between the terminal equipment and the access network equipment can be realized, and the communication capability of the terminal equipment is improved.

In a possible implementation method, the clock management network element sends a query message to the unified database network element, where the query message includes identification information of the terminal device, and the query message requests to obtain a policy control network element that provides services for the terminal device; the clock management network element receives the identification information of the policy control network element from the unified database network element.

In a possible implementation method, the clock management network element sends a request message to the unified data management network element, where the request message includes identification information of the terminal device, and the request message is used to request whether to authorize providing a time synchronization service for the terminal device; the clock management network element receives a response message from the unified data management network element, the response message indicating authorization to provide time-setting services for the terminal device.

According to the scheme, if the clock management network element determines that the terminal equipment is authorized to acquire the time setting service, the access network equipment is instructed to provide the time setting service for the terminal equipment, and the time setting service for unauthorized terminal equipment is avoided.

In a possible implementation method, the clock management network element receives the pair of time request messages from the terminal device or the application function network element.

In a fourth aspect, embodiments of the present application provide a communication apparatus, which may be a terminal device or a module (e.g. a chip) in a terminal device. The apparatus has the function of implementing any implementation method of the first aspect. The functions can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

In a fifth aspect, embodiments of the present application provide a communications apparatus that may be an access network device or a module (e.g., a chip) in an access network device. The apparatus has the function of implementing any implementation method of the second aspect. The functions can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

In a sixth aspect, embodiments of the present application provide a communications device, which may be a clock management network element or a module (e.g., a chip) in a clock management network element. The apparatus has a function of implementing any implementation method of the third aspect. The functions can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

In a seventh aspect, an embodiment of the present application provides a communication apparatus, including a processor and a memory; the memory is configured to store computer instructions that, when executed by the apparatus, cause the apparatus to perform any of the implementation methods of the first to third aspects described above.

In an eighth aspect, embodiments of the present application provide a communications apparatus comprising means for performing the steps of any of the implementing methods of the first to third aspects described above.

In a ninth aspect, an embodiment of the present application provides a communication device, including a processor coupled to a memory, the processor being configured to invoke a program stored in the memory, to perform any implementation method of the first aspect to the third aspect. The memory may be located within the device or may be located external to the device. And the processor may be one or more.

In a tenth aspect, an embodiment of the present application provides a communication device, including a processor and an interface circuit, where the processor is configured to communicate with other devices through the interface circuit, and perform any implementation method of the first aspect to the third aspect. The processor includes one or more.

In an eleventh aspect, embodiments of the present application also provide a computer program product comprising a computer program or instructions which, when executed by a communication device, cause any of the implementation methods of the first to third aspects described above to be performed.

In a twelfth aspect, embodiments of the present application further provide a computer-readable storage medium having instructions stored therein that, when executed on a communication device, cause any implementation method of the first to third aspects described above to be performed.

In a thirteenth aspect, an embodiment of the present application further provides a chip system, including: a processor configured to perform any implementation method of the first to third aspects.

In a fourteenth aspect, an embodiment of the present application further provides a communication system, including a terminal device configured to perform any of the methods of the first aspect, and an access network device configured to perform any of the methods of the second aspect.

Drawings

FIG. 1 (a) is a schematic diagram of a 5G network architecture based on a servitization architecture;

FIG. 1 (b) is a schematic diagram of a 5G network architecture based on a point-to-point interface;

FIG. 2 is a flowchart of a time synchronization method according to an embodiment of the present application;

FIG. 3 (a) is an exemplary diagram of a time synchronization provided by an embodiment of the present application;

FIG. 3 (b) is a diagram illustrating another example of time synchronization provided by an embodiment of the present application;

FIG. 3 (c) is a diagram illustrating another example of time synchronization provided by an embodiment of the present application;

FIG. 4 is a flowchart of a time synchronization method according to an embodiment of the present application;

FIG. 5 is a flowchart of a time synchronization method according to an embodiment of the present application;

FIG. 6 is a flowchart of a time synchronization method according to an embodiment of the present application;

fig. 7 is a schematic diagram of a communication device according to an embodiment of the present application;

fig. 8 is a schematic diagram of a communication device according to an embodiment of the present application.

Detailed Description

Fig. 1 (a) is a schematic diagram of a 5G network architecture based on a servitization architecture. The 5G network architecture shown in fig. 1 (a) includes a Data Network (DN) and an operator network. The function of some of these network elements is briefly described below.

The operator network comprises one or more of the following network elements: AN authentication server function (Authentication Server Function, AUSF) network element (not shown in the figure), a unified data management (unified data management, UDM) network element, a unified database (Unified Data Repository, UDR) network element, a network storage function (Network Repository Function, NRF) network element (not shown in the figure), a network opening function (network exposure function, NEF) network element (not shown in the figure), AN application function (application function, AF) network element, a policy control function (policy control function, PCF) network element, AN access and mobility management function (access and mobility management function, AMF) network element, a session management function (session management function, SMF) network element, a UPF network element, AN Access Network (AN) device (in the figure, a radio access network (radio access network, RAN) device is taken as AN example), a time sensitive communication and time synchronization function (Time Sensitive Communication and Time Synchronization Function, TSCTSF) network element, etc. In the above-mentioned operator network, the network elements or devices other than the access network device may be referred to as core network elements or core network devices.

The access network device comprises a wired access network device and a wireless access network device. Wherein the radio access network device may be a base station (base station), an evolved NodeB (eNodeB), a transmission and reception point (transmission reception point, TRP), a next generation NodeB (gNB) in a 5G mobile communication system, a next generation base station in a sixth generation (6th generation,6G) mobile communication system, a base station in a future mobile communication system, or an access node in a wireless fidelity (wireless fidelity, wiFi) system, etc.; the present application may also be a module or unit that performs a function of a base station part, for example, a Central Unit (CU) or a Distributed Unit (DU). The radio access network device may be a macro base station, a micro base station, an indoor station, a relay node, a donor node, or the like. The specific technology and specific device configuration adopted by the access network device in the embodiment of the application are not limited.

Terminal devices in communication with the RAN include terminals, user Equipment (UE), mobile stations, mobile terminals, and the like. The terminal device is taken as an example in the figure as UE. The terminal device may be widely applied to various scenes, for example, device-to-device (D2D), vehicle-to-device (vehicle to everything, V2X) communication, machine-type communication (MTC), internet of things (internet of things, ioT), virtual reality, augmented reality, industrial control, autopilot, telemedicine, smart grid, smart furniture, smart office, smart wear, smart transportation, smart city, etc. The terminal can be a mobile phone, a tablet personal computer, a computer with a wireless receiving and transmitting function, a wearable device, a vehicle, an unmanned aerial vehicle, a helicopter, an airplane, a ship, a robot, a mechanical arm, intelligent household equipment and the like. The embodiment of the application does not limit the specific technology and the specific equipment form adopted by the terminal equipment.

The access network device and the terminal device may be fixed in location or may be mobile. The access network equipment and the terminal equipment can be deployed on land, including indoor or outdoor, handheld or vehicle-mounted; the device can be deployed on the water surface; but also on aerial planes, balloons and satellites. The embodiment of the application does not limit the application scene of the access network equipment and the terminal equipment.

The mobility management network element is a control plane network element provided by the operator network and is responsible for access control and mobility management of the terminal equipment accessing the operator network, for example, the mobility management comprises the functions of mobility state management, user temporary identity identification allocation, user authentication, user authorization and the like. In 5G, the mobility management element may be an AMF element, and in future communications such as the sixth generation (the 6th generation,6G), the mobility management element may still be an AMF element, or have other names, which is not limited by the present application.

The session management network element is a control plane network element provided by the operator network and is responsible for managing protocol data unit (protocol data unit, PDU) sessions of the terminal devices. A PDU session is a channel for transmitting PDUs, and the terminal device needs to transmit PDUs to each other through the PDU session and DN. The PDU session is responsible for establishment, maintenance, deletion, etc. by the SMF network element. Session management network elements include session-related functions such as session establishment, modification and release, including tunnel maintenance between user plane network elements and access network devices, selection and control of user plane network elements, traffic and session continuity (Service and Session Continuity, SSC) mode selection, roaming, etc. In 5G, the session management network element may be an SMF network element, and in future communications such as 6G, the session management network element may still be an SMF network element, or have other names, which is not limited by the present application.

The user plane network element is a gateway provided by an operator, and is a gateway for the operator network to communicate with the DN. The UPF network element comprises functions related to user planes such as data packet routing and transmission, packet detection, traffic reporting, quality of service (Quality of Service, qoS) processing, lawful interception, uplink packet detection, downlink data packet storage and the like. In 5G, the user plane element may be a UPF element, and in future communications such as 6G, the user plane element may still be a UPF element, or have other names, which is not limited by the present application.

The data management network element is a control plane network element provided by an operator and is responsible for storing information such as a user permanent identifier (subscriber permanent identifier, SUPI), a trust (security context), subscription data and the like of an signing user in an operator network. This information stored by the data management network element may be used for authentication and authorization of the terminal device to access the operator network. The subscriber of the operator network may be a subscriber using a service provided by the operator network, for example, a subscriber using a mobile phone core card of chinese telecommunication, or a subscriber using a mobile phone core card of chinese mobile. The permanent subscription identifier (Subscription Permanent Identifier, SUPI) of the subscriber may be the number of the mobile phone core card, etc. The credentials and security context of the subscriber may be a small file stored in the encryption key of the mobile phone core card or information related to the encryption of the mobile phone core card, for authentication and/or authorization. The security context may be data (cookie) or token (token) stored on the user's local terminal (e.g., handset), etc. The subscription data of the subscriber can be the matched service of the mobile phone core card, such as the flow package of the mobile phone core card or the use network. It should be noted that, in the present document, the permanent identifier, the credentials, the security context, the authentication data (cookie), and the authentication and authorization related information such as the token are not distinguished or limited for convenience of description. Unless specifically stated, embodiments of the present application will be described by way of example in the context of security, but embodiments of the present application are equally applicable to authentication, and/or authorization information in other expressions. In 5G, the data management network element may be a UDM network element, and in future communications such as 6G, the data management network element may still be a UDM network element, or have other names, which is not limited by the present application.

The unified database network element is a control plane network element provided by an operator and comprises an access function for executing type data such as subscription data, policy data, application data and the like. In 5G, the unified database network element may be a UDR network element, and in future communications such as 6G, the unified database network element may still be a UDR network element, or have other names, which is not limited by the present application.

The network opening network element is a control plane network element provided by an operator. The network opening network element opens an external interface of the operator network to the third party in a secure manner. When the session management network element needs to communicate with the network element of the third party, the network opening network element can be used as a relay for the session management network element to communicate with the network element of the third party. When the network opens the network element as a relay, the network element can be used as the translation of the identification information of the contracted user and the translation of the identification information of the network element of a third party. For example, when the network opening network element transmits the SUPI of the subscriber from the operator network to the third party, the SUPI may be translated into the corresponding external identity. Conversely, when the network element opens the network element to send the external ID (the network element ID of the third party) to the operator network, it may be translated into SUPI. In 5G, the network opening network element may be a NEF network element, and in future communications such as 6G, the network opening network element may still be a NEF network element, or have other names, which is not limited by the present application.

The application function network element is used for transmitting the requirement of the application side to the network side, such as QoS requirement or user state event subscription. The application function network element may be a third party function entity or an application server deployed by an operator. In 5G, the application function element may be an AF element, and in future communications such as 6G, the application function element may still be an AF element, or have other names, which is not limited by the present application.

The policy control network element is a control plane function provided by the operator for providing the session management network element with policies for PDU sessions. Policies may include charging related policies, qoS related policies, and authorization related policies, among others. In 5G, the policy control network element may be a PCF network element, and in future communications, such as 6G, the policy control network element may still be a PCF network element, or have other names, which is not limited by the present application.

The network storage function network element can be used for providing a network element discovery function and providing network element information corresponding to the network element type based on the request of other network elements. Network storage function the network element also provides network element management services such as network element registration, updating, deregistration, network element state subscription and push, etc. In 5G, the network storage function element may be an NRF element, and in future communications such as 6G, the network storage function element may still be an NRF element, or have other names, which is not limited by the present application.

The clock management network element may be configured to manage clock information of one or more clock sources of the 5G network, and may provide clock information of the clock sources to the outside through its own port, for example, directly or indirectly provide clock information to a terminal device, an access network device, a core network device, or a third party application function network element. Wherein the clock information represents time, moment or time point of the clock; the clock management network element can also select a corresponding time service network element according to the time service request of the time service request party, wherein the time service network element can be a UPF network element, an access network device and the like, or can be the clock management network element itself, and then the clock management network element indicates the time service network element to provide time service for the time service request party. In 5G, the clock management network element may be a TSCTSF network element defined by 3GPP, and in future communications such as 6G, the clock management network element may still be a TSCTSF network element, or have other names, which is not limited by the present application.

The DN is a network outside the operator network, the operator network can be accessed to a plurality of DNs, a plurality of services can be deployed on the DNs, and services such as data and/or voice can be provided for the terminal equipment. For example, the DN is a private network of an intelligent plant, the sensors installed in the plant of the intelligent plant may be terminal devices, a control server of the sensors is disposed in the DN, and the control server may serve the sensors. The sensor may communicate with the control server, obtain instructions from the control server, transmit collected sensor data to the control server, etc., according to the instructions. For another example, DN is an internal office network of a company, where a mobile phone or a computer of an employee of the company may be a terminal device, and the mobile phone or the computer of the employee may access information, data resources, etc. on the internal office network of the company.

Npcf, nudr, nudm, naf, namf, nsmf, ntsctsf in fig. 1 (a) are service interfaces provided by the PCF network element, the UDR network element, the UDM network element, the AF network element, the AMF network element, the SMF network element, and the TSCTSF network element, respectively, and are used for invoking corresponding service operations. N1, N2, N3, N4, and N6 are interface serial numbers, and the meaning of these interface serial numbers is as follows:

1) N1: the interface between the AMF network element and the UE may be used to communicate non-access stratum (non access stratum, NAS) signaling (e.g., including QoS rules from the AMF network element) to the UE, etc.

2) N2: the interface between the AMF network element and the radio access network device may be used to transfer radio bearer control information from the core network side to the radio access network device, etc.

3) N3: the interface between the wireless access network device and the UPF network element is mainly used for transmitting uplink user plane data and/or downlink user plane data between the wireless access network device and the UPF network element.

4) N4: the interface between the SMF network element and the UPF network element can be used for transferring information between the control plane and the user plane, including controlling the issuing of forwarding rules, qoS rules, flow statistics rules and the like facing the user plane and the information reporting of the user plane.

5) N6: and the interface of the UPF network element and the DN is used for transmitting uplink user data flow and/or downlink user data flow between the UPF network element and the DN.

Fig. 1 (b) is a schematic diagram of a 5G network architecture based on a point-to-point interface, where the description of the functions of the network elements may refer to the description of the functions of the corresponding network elements in fig. 1 (a), and will not be repeated. The main difference between fig. 1 (b) and fig. 1 (a) is that: the interfaces between the individual control plane network elements in fig. 1 (a) are served interfaces and the interfaces between the individual control plane network elements in fig. 1 (b) are point-to-point interfaces.

In the architecture shown in fig. 1 (b), the interface names and functions between the network elements are as follows:

1) The meaning of the N1, N2, N3, N4 and N6 interfaces may be referred to the foregoing description.

2) N5: the interface between the AF network element and the PCF network element can be used for issuing application service requests and reporting network events.

3) N7: the interface between PCF network element and SMF network element can be used to deliver protocol data unit (protocol data unit, PDU) session granularity and traffic data flow granularity control policies.

4) N8: the interface between the AMF network element and the UDM network element can be used for the AMF network element to acquire subscription data and authentication data related to access and mobility management from the UDM network element, and the AMF network element to register terminal equipment mobility management related information and the like from the UDM network element.

5) N9: the user interface between UPF network elements is used for transmitting uplink user data flow and/or downlink user data flow between UPF network elements.

6) N10: the interface between the SMF network element and the UDM network element may be used for the SMF network element to obtain session management related subscription data from the UDM network element, and the SMF network element to register terminal device session related information from the UDM network element.

7) N11: the interface between the SMF network element and the AMF network element may be used to transfer PDU session tunnel information between the radio access network device and the UPF network element, transfer control information sent to the terminal device, transfer radio resource control information sent to the radio access network device, and so on.

8) N15: the interface between the PCF network element and the AMF network element may be used for issuing terminal device policies and access control related policies.

9) N35: the interface between the UDM network element and the UDR network element may be used for the UDM network element to obtain the user subscription data information from the UDR network element.

10 N36): the interface between the PCF network element and the UDR network element may be used for the PCF network element to obtain policy related subscription data and application data related information from the UDR network element.

It will be appreciated that the network elements or functions described above may be either network elements in a hardware device, software functions running on dedicated hardware, or virtualized functions instantiated on a platform (e.g., a cloud platform). Alternatively, the network element or the function may be implemented by one device, or may be implemented by a plurality of devices together, or may be a functional module in one device, which is not specifically limited in the embodiment of the present application.

In the embodiment of the application, the base station and the UE are respectively used as specific examples of the access network equipment and the terminal equipment.

Fig. 2 is a flowchart of a time synchronization method according to an embodiment of the present application, where the method includes the following steps:

in step 201, the base station determines time tick information.

Optionally, before step 201, the base station receives indication information, where the indication information indicates to provide time synchronization service for the UE. The indication information triggers the base station to determine the pair of time information.

In step 202, the base station sends time synchronization information to the UE, where the time synchronization information is used for local time synchronization of the UE.

After receiving the time setting information, the UE stores the receiving time of the time setting information and the time setting information.

In step 203, the UE performs time synchronization according to the current time of the UE, the time of receiving the time synchronization information, and the time synchronization information.

In a possible implementation method, when a preset condition is met, the UE performs time synchronization according to the current time of the UE, the time of receiving the time-setting information, and the time-setting information; wherein, the preset conditions are as follows: the UE does not receive new time setting information from the base station within a set time length; or the UE receives the indication information and the new time setting information from the base station in the set time length, wherein the indication information indicates that the new time setting information does not meet the time setting precision requirement of the UE.

The set duration may be sent to the UE by the base station, or may be preset on the UE.

According to the scheme, the UE can realize accurate time synchronization between the UE and the base station according to the time setting information received from the base station before, and the UE does not depend on the base station to provide the time setting information in time, so that when the base station cannot send new time setting information to the UE or the base station cannot send new time setting information to the UE in time, the UE can finish time setting, and the communication capability of the UE is improved.

In an implementation method, before the step 201, the UE further sends a time synchronization request message to a base station or a core network element (such as an AMF network element, a TSCTSF network element, etc.), where the time synchronization request message includes identification information and indication information of the UE, where the indication information indicates that a time synchronization service is provided for the UE.

In an implementation method, before the step 203, the UE performs time synchronization according to the time synchronization information from the base station. For example, when the pair time information includes a transmission delay and a transmission time of the pair time information, the transmission delay represents a transmission delay between the UE and the base station, and the UE performs time synchronization according to the transmission delay and the transmission time of the pair time information. For another example, when the pair of time information includes a clock bias indicating a clock bias between the UE and the base station, the UE performs time synchronization according to the clock bias and a reception time of the pair of time information. In this way, accurate time synchronization can be achieved.

In an implementation method, before the step 203, the UE further receives information for indicating to start the time synchronization function from a base station or a core network element (such as an AMF network element, a TSCTSF network element, etc.), and the UE starts the time synchronization function according to the information, so that when the UE does not receive new time synchronization information from the base station within a set duration, the UE performs time synchronization according to the current time of the UE, the receiving time of the time synchronization information, and the time synchronization information. This scheme facilitates time synchronization by the UE in the correct way.

In the implementation method, in the step 203, the UE performs time synchronization according to the current time of the UE, the time of receiving the time synchronization information, and the time synchronization information, which may specifically be: the UE determines a difference value between the current time of the UE and the receiving time of the time synchronization information, then determines a synchronization time according to the difference value and the time synchronization information, and performs time synchronization according to the synchronization time.

Three different methods for determining the synchronization time by the UE according to the difference between the current time of the UE and the reception time of the time synchronization information and the time synchronization information are described below.

In the first method, the time setting information received by the UE comprises a clock frequency ratio and a clock deviation, the UE determines the ratio of the difference value to the clock frequency ratio, and determines the synchronous time according to the ratio, the clock deviation and the receiving time of the time setting information.

Wherein the clock frequency ratio represents the ratio between the clock frequency of the UE and the clock frequency of the base station. For example, the time when the base station sends the message to the UE and the time when the UE receives the message, and the time when the UE sends the message to the base station and the time when the base station receives the message can be calculated.

The clock bias represents the difference between the clock of the UE and the clock of the base station.

Illustratively, the synchronization time= (tx-ty)/ratio+ty+offset.

Wherein tx represents the current time of the terminal device, ty represents the receiving time of the time synchronization information, ratio represents the clock frequency ratio, offset represents the clock offset between the base station and the UE at the moment of ty, and tx-ty represents the difference between the current time of the UE and the receiving time of the time synchronization information.

In the above formula, the UE receives the offset at the ty time, and the UE updates the time of the UE to be ty+offset, so as to achieve time synchronization with the base station at the ty time. Then, after the (tx-ty) period has elapsed, the UE takes the sum of the elapsed time and the time of the UE at the ty time as the synchronization time of the UE at the tx time. I.e., the sum of (tx-ty)/ratio and (ty + offset) is taken as the synchronization time of the UE. Among them, division by ratio is required because it is required to convert the time elapsed in the UE domain into the time elapsed in the base station domain. The method can realize accurate synchronization of the time of the UE and the time of the base station under the condition that the UE does not receive the time synchronization information of the base station or the received new time synchronization information is not accurate enough.

In the second method, the time setting information received by the UE comprises a clock frequency ratio, a transmission delay and a sending time of the time setting information, the UE determines a ratio of a difference value to the clock frequency ratio, and the UE determines a synchronous time according to the ratio, the transmission delay and the sending time of the time setting information.

The clock frequency ratio represents the clock frequency ratio between the UE and the base station, and the transmission delay represents the transmission delay between the UE and the base station.

Illustratively, synchronization time= (tx-ty)/ratio+tz+delay.

Wherein tx represents the current time of the terminal device, ty represents the receiving time of the time synchronization information, tz represents the sending time of the time synchronization information, ratio represents the clock frequency ratio, delay represents the transmission delay, and tx-ty represents the difference between the current time of the UE and the receiving time of the time synchronization information.

In the formula, the UE receives tz and delay at the ty moment, and the UE updates the time of the UE to tz+delay, so that the time synchronization with the base station is completed at the ty moment. Then, after the (tx-ty) period has elapsed, the UE takes the sum of the elapsed time and the time of the UE at the ty time as the synchronization time of the UE at the tx time. I.e. the sum of (tx-ty)/ratio and (tz + delay) is taken as the synchronization time of the UE. Among them, division by ratio is required because it is required to convert the time elapsed in the UE domain into the time elapsed in the base station domain. The method can realize accurate synchronization of the time of the UE and the time of the base station under the condition that the UE does not receive the time synchronization information of the base station or the received new time synchronization information is not accurate enough.

The method comprises the steps that the time setting information received by the UE comprises a clock deviation change rate, a clock frequency ratio and a clock deviation, the UE determines the product of the clock deviation change rate and the difference value, determines the ratio of the product to the clock frequency ratio, and then determines the synchronous time according to the ratio, the clock deviation and the current time of the UE.

The clock deviation change rate represents the change amount of clock deviation along with time, the clock frequency ratio represents the clock frequency ratio between the UE and the base station, and the clock deviation represents the clock deviation between the UE and the base station.

Illustratively, synchronization time = tx+drift (tx-ty)/ratio+offset.

Wherein tx represents the current time of the terminal device, ty represents the receiving time of the time synchronization information, drift represents the clock deviation change rate, that is, the change rate of the clock deviation between the base station and the UE with time, ratio represents the clock frequency ratio, offset represents the clock deviation between the base station and the UE at the time of ty, and tx-ty represents the difference between the current time of the UE and the receiving time of the time synchronization information.

Wherein, the drift can be determined by: the base station determines a first clock bias at a first time and a second clock bias at a second time, and then determines a drift, in particular, drift= (second clock bias-first clock bias)/(second time-first time), based on a first difference between the second clock bias and the first clock bias and a second difference between the second time and the first time.

The above formula, the UE receives the offset at the ty time, that is, the offset represents the offset between the base station and the UE at the ty time. Then, after the (tx-ty) period has elapsed, the offset between the base station and the UE changes, and the offset change amount is drift (tx-ty)/ratio, so drift (tx-ty)/ratio+offset represents the clock offset between the base station and the UE at the tx time. Therefore, the UE uses the sum of tx and (drift) as the synchronization time of the UE at tx, so that time synchronization can be achieved. Among them, division by ratio is required because it is required to convert the time elapsed in the UE domain into the time elapsed in the base station domain. The method can realize accurate synchronization of the time of the UE and the time of the base station under the condition that the UE does not receive the time synchronization information of the base station or the received new time synchronization information is not accurate enough.

The three methods described above are described below with reference to specific examples shown in fig. 3 (a), 3 (b) and 3 (c).

Fig. 3 (a) is an exemplary diagram of time synchronization provided in an embodiment of the present application. The method comprises the following steps:

time t 1: the base station sends a message 1 to the UE at the time t 1;

time t 2: the UE receives a message 1 at a time t 2;

time t 3: the UE sends a message 2 to the base station at the time t3, and the message header of the message 2 carries the receiving time t2 of the message 1 and the sending time t3 of the message 2;

time t 4: the base station receives the message 2 at the time t 4;

time t 5: the UE sends a message 3 to the base station at the time t5, and the message header of the message 3 carries the sending time t5 of the message 3;

time t 6: the base station receives the message 3 at time t 6.

The base station may execute the following method a or method B when it acquires the time t1 to t 6. Here, the method a is an example of the first method, and the method B is an example of the second method.

In the method A, the base station calculates the ratio and the offset, and sends the ratio and the offset to the UE.

ratio= (t 5-t 3)/(t 6-t 4). ratio represents the ratio of clock frequencies between the UE and the base station.

offset= ((t 2-t 1) - (t 4-t 3))/2. offset represents the clock offset between the UE and the base station.

Assuming that the base station transmits the time synchronization information to the UE at time t7, and the UE receives the time synchronization information at time t8, where the time synchronization information includes a ratio and an offset, the UE performs time synchronization according to the offset, and a time after the UE performs time synchronization is t_new 1=t8+offset. And, the UE also saves the received time tick information. Subsequently, if the UE does not receive new time synchronization information from the base station within the set time length, the UE starts local time synchronization. For example, if the current time of the UE is t9, the time after the UE performs local time synchronization is t_new 2= (t 9-t 8)/ratio+t8+offset. Here, the ratio and offset come from the time tick information last received and saved by the UE.

And B, the base station calculates the ratio and the delay, and sends the ratio and the delay to the UE.

delay= (ratio) (t 4-t 1) - (t 3-t 2))/2. delay represents the transmission delay between the UE and the base station.

Assuming that the base station sends time synchronization information to the UE at time t7, and the UE receives the time synchronization information at time t8, where the time synchronization information includes t7, ratio and delay, the UE performs time synchronization according to t7 and delay, and the time after the UE performs time synchronization is t_new 1=t7+delay. And, the UE also saves the received time tick information. Subsequently, if the UE does not receive new time synchronization information from the base station within the set time length, the UE starts local time synchronization. For example, if the current time of the UE is t9, the time after the UE performs local time synchronization is t_new 2= (t 9-t 8)/ratio+t7+delay. Wherein, t7, ratio and delay come from the last time the UE received and saved the time synchronization information.

Fig. 3 (b) is a diagram illustrating another example of time synchronization according to an embodiment of the present application. The main differences between fig. 3 (b) and fig. 3 (a) are: in fig. 3 (a), a message may carry the sending time of the message, for example, message 2 carries t3, and message 3 carries t5; in fig. 3 (b), the sending time of a message is not carried in the message, for example, message 2 does not carry t3, and message 3 does not carry t5. Based on the above difference, in fig. 3 (a), the UE transmits time information to the base station by transmitting 2 messages to the base station, the time information including t2, t3 and t5, and in fig. 3 (b), the UE transmits time information to the base station by transmitting 3 messages to the base station, the time information including t2, t3 and t5. Based on other aspects of the embodiment of fig. 3 (b), it is identical to the embodiment of fig. 3 (a) described above.

Fig. 3 (c) is a diagram illustrating another example of time synchronization according to an embodiment of the present application. The method comprises the following steps:

time t 1: the base station sends a message 1 to the UE at the time t 1;

time t 2: the UE receives a message 1 at a time t 2;

time t 4: the base station receives the message 2 at the time t 4;

time t 5: the base station sends a message 3 to the UE at the time t 5;

time t 6: the UE receives a message 3 at a time t 6;

time t 7: the UE sends a message 4 to the base station at the time t7, and the message header of the message 4 carries the receiving time t6 of the message 3 and the sending time t7 of the message 4;

time t 8: the base station receives message 4 at time t 8.

The base station acquires the time points t1 to t8, and can execute the following method C. This method C is an example of the above-described method three.

In the method C, the base station calculates the drift, the ratio and the offset, and sends the drift, the ratio and the offset to the UE.

First, the base station calculates a drift and a ratio. Wherein, drift= (offset 2-offset 1)/(t 8-t 4), offset 1= ((t 2-t 1) - (t 4-t 3))/2, offset 2= ((t 6-t 5) - (t 8-t 7))/2, both offset1 and offset2 represent clock offset between UE and base station, drift represents variation of offset with time. ratio= (t 7-t 3)/(t 8-t 4), ratio represents the clock frequency ratio between UE and base station.

Then, the base station transmits, to the UE at time t9, the pair of time information including ratio, drift and offset2, which is received by the UE at time t10, and the time after the UE performs the pair is t_new 1=t10+offset 2. And, the UE also saves the received time tick information. Subsequently, if the UE does not receive new time synchronization information from the base station within the set time length, the UE starts local time synchronization. For example, if the current time of the UE is t11, the time after the UE performs local time synchronization is t_new 2=t11+drift/ratio (t 11-t 10) +offset2. The drift, ratio, and offset2 here are derived from the time synchronization information that the UE last received and stored.

In the embodiment of the present application, the method a and the method B may be referred to as a Round Trip Time (RTT) timing method, and the method C may be referred to as a bidirectional RTT timing method.

The embodiment of fig. 2 described above will be specifically described with reference to the specific embodiments of fig. 4 to 6.

Fig. 4 is a flowchart of a time synchronization method according to an embodiment of the present application. The method is that AF requests to provide time service for UE.

The method comprises the following steps:

in step 401, the af sends a time synchronization request message to the NEF, where the time synchronization request message includes identification information of the UE, the required time synchronization error accuracy, and indication information.

The UE indicated by the identification information of the UE is the object needing time synchronization.

The required timing error accuracy may be nanoseconds (ns), microseconds (us), etc.

In one implementation, the indication information indicates to provide time-setting services for the UE.

In yet another implementation, the indication information indicates that the UE is provided with a time tick service according to an enhanced RTT time tick method.

In yet another implementation, the indication information indicates that the UE is provided with a time tick service according to a bidirectional RTT time tick method.

Optionally, the pair of time request messages is an nnef_timesynchronization_update/Update/Delete message.

In step 402, the nef sends a time synchronization request message to the TSCTSF, where the time synchronization request message includes identification information of the UE, a required time synchronization error precision, and indication information.

After receiving the time setting request message from the AF, the NEF authenticates the AF, and when the authentication is passed, the NEF sends the time setting request message to the TSCTSF. The identification information, the required time setting error precision and the indication information of the UE in the time setting request message sent by the NEF come from AF.

Optionally, the pair of time request messages is an ntsctssf_timesynchronization_update_update/Delete message.

In step 403, the tsctsf selects a base station providing time-setting service for the UE.

For example, the TSCTSF selects a base station providing a timing service for the UE from a plurality of base stations according to distribution information of the base stations and a required timing error accuracy.

In step 404, the tsctsf sends a query message to the UDR, the query message including identification information of the UE, the query message requesting to obtain a PCF that serves the UE.

In one implementation, the query message is a Nudr_DM_Create/Update/Delete request message.

In step 405, the udr sends a response message to the TSCTSF, the response message including identification information of the PCF.

In one implementation, the response message is a Nudr_DM_Create/Update/Delete response message.

In step 406, the tsctsf sends a notification message to the PCF, the notification message including identification information of the UE, identification information of the base station, indication information, and required timing error accuracy.

The base station is the base station selected by the TSCTSF and providing the UE with the time synchronization service, and the identification information, the indication information and the required time synchronization error precision of the UE are received by the TSCTSF in step 402.

In step 407, the pcf sends policy information to the AMF, where the policy information includes identification information of the UE, identification information of the base station, indication information, and required timing error accuracy.

The UE identification information, the base station identification information, the indication information, and the required timing error accuracy in the policy information are received by the PCF from the TSCTSF.

In step 408, the amf sends a notification message to the base station, the notification message including the identification information, the indication information, and the required timing error accuracy of the UE.

The base station is the base station indicated by the identification information of the base station in the policy information.

The identification information, indication information and the required timing error accuracy of the UE in the notification message are received by the AMF from the PCF.

In step 409, the base station determines the timing information according to the required timing error accuracy.

That is, the timing information determined by the base station is the timing error precision meeting the requirement.

In the implementation method, when the indication information received by the base station indicates that the time setting service is provided for the UE, the base station selects an enhanced RTT time setting method or a bidirectional RTT time setting method according to the required time setting error precision. Specifically, if the enhanced RTT timing method is selected, the base station determines timing information according to the enhanced RTT timing method and the required timing error accuracy, and the content of the timing information may refer to the foregoing method a or method B. If a bidirectional RTT timing method is selected, the base station determines timing information according to the bidirectional RTT timing method and the required timing error accuracy, and the content of the timing information may refer to the method C.

In still another implementation method, when the indication information received by the base station indicates that the UE is provided with the time setting service according to the enhanced RTT method, the base station determines the time setting information according to the enhanced RTT time setting method and the required time setting error precision, and the content of the time setting information may refer to the foregoing method a or method B.

In still another implementation method, when the indication information received by the base station indicates that the UE is provided with the time setting service according to the bidirectional RTT method, the base station determines the time setting information according to the bidirectional RTT time setting method and the required time setting error precision, and the content of the time setting information may refer to the foregoing method C.

In step 410, the base station transmits the time synchronization information to the UE.

Optionally, the base station further sends information for indicating the time setting function to the UE, so that the UE starts the time setting function according to the information, which is helpful for accurately implementing time synchronization.

In step 411, the ue performs time synchronization according to the time synchronization information.

Specific implementation of this step 411 may refer to the description of the embodiment of fig. 2, and will not be repeated.

Alternatively, after the above step 406, the TSCTSF may send a time tick response message to notify the NEF of the success of the time tick, and then the NEF sends a time tick response message to the AF to notify the success of the time tick.

According to the scheme, the AF requests the time setting service for the UE, the TSCTSF selects the base station providing the time setting service for the UE, and the base station transmits the time setting information to the UE, so that when the base station cannot transmit the time setting information to the UE or the base station cannot timely transmit the time setting information to the UE, the UE can realize accurate time synchronization between the UE and the base station according to the time setting information received from the base station before, and the communication capability of the UE is improved.

Fig. 5 is a flowchart of a time synchronization method according to an embodiment of the present application. The method is that when the clock source on the base station fails, the UE performs time synchronization according to the time synchronization information stored locally.

The method comprises the following steps:

in step 501, the base station sends a notification message to the TSCTSF, where the notification message includes identification information of the base station and indication information 1, where the indication information 1 indicates that a clock source of the base station fails.

Optionally, the notification message further includes identification information of the UE, which is affected by the clock source failure of the base station. That is, the time tick service cannot be continuously provided to the UE due to the clock source failure of the base station.

In step 502, the tsctsf determines UEs affected by a clock source failure of the base station.

When the notification message of the above step 501 carries the identification information of the UE affected by the clock source failure of the base station, it is not necessary to perform the step 502.

When the notification message of the above step 501 carries the identification information of the UE affected by the clock source failure of the base station, the step 502 is performed. In one implementation method, the TSCTSF sends a request message to the AMF/PCF, where the request message includes identification information of a base station, the request message requests to obtain identification information of a UE affected by a clock source failure of the base station, and then the AMF/PCF sends the identification information of the UE affected by the clock source failure of the base station to the TSCTSF.

In step 503, the tsctsf sends a query message to the UDR, the query message including identification information of the UE, the query message requesting to obtain a PCF that serves the UE.

The UE indicated by the identification information of the UE is the UE affected by the clock source fault of the base station.

In step 504, the udr sends a response message to the TSCTSF, the response message including identification information of the PCF.

In step 505, the tsctsf transmits a notification message to the PCF, the notification message including identification information and indication information 2 of the UE.

The indication information 2 indicates the UE to perform local time synchronization.

In step 506, the pcf sends policy information to the AMF, the policy information including identification information and indication information 2 of the UE.

In step 507, the amf sends indication information 2 to the UE.

Optionally, the AMF further sends information for indicating the time setting function to the UE, so that the UE starts the time setting function according to the information, which is helpful for accurately implementing time synchronization.

In step 508, the ue performs time synchronization according to the locally stored time synchronization information.

The specific implementation of this step 508 may refer to the description of the embodiment of fig. 2, and will not be repeated.

According to the scheme, when the clock source of the base station fails, the TSCTSF can inform the UE of carrying out local time synchronization, namely, the UE realizes accurate time synchronization between the UE and the base station according to the time synchronization information received from the base station before, and is beneficial to improving the communication capability of the UE.

Fig. 6 is a flowchart of a time synchronization method according to an embodiment of the present application. The method is that the UE actively requests to provide time setting service for the UE.

The method comprises the following steps:

in step 601, the UE sends a time synchronization request message to the AMF, where the time synchronization request message includes identification information of the UE, a required time synchronization error precision, and indication information.

Optionally, the pair of time request messages is an nnas_time synchronization_update/Update/Delete message.

In step 602, the amf sends a time synchronization request message to the TSCTSF, where the time synchronization request message includes identification information of the UE, a required time synchronization error precision, and indication information.

The identification information, the required time setting error precision and the indication information of the UE in the time setting request message sent by the AMF come from the UE.

In step 603, the tsctsf transmits a request message to the UDM, the request message including identification information of the UE.

When the indication information received by the TSCTSC indicates that the UE is provided with the time-setting service, a request message sent by the TSCTSF to the UDM is used to request to query whether the UE is authorized to be provided with the time-setting service.

When the indication information received by the TSCTSC indicates that the UE is provided with the time setting service according to the enhanced RTT time setting method, the request message sent by the TSCTSF to the UDM is used to request whether to authorize providing the UE with the time setting service according to the enhanced RTT time setting method.

When the indication information received by the TSCTSC indicates that the UE is provided with the time setting service according to the bidirectional RTT time setting method, the request message sent by the TSCTSF to the UDM is used for requesting whether to authorize providing the UE with the time setting service according to the bidirectional RTT time setting method.

In step 604, the udm sends a response message to the TSCTSF.

The response message indicates that the UE is authorized to provide the time-setting service, or indicates that the UE is authorized to provide the time-setting service according to the enhanced RTT time-setting method, or indicates that the UE is authorized to provide the time-setting service according to the bidirectional RTT time-setting method.

Steps 605 to 613 are the same as steps 403 to 411 described above.

According to the scheme, the UE actively requests the time setting service, the TSCTSF selects the base station providing the time setting service for the UE, and the base station transmits the time setting information to the UE, so that when the base station cannot transmit the time setting information to the UE or the base station cannot timely transmit the time setting information to the UE, the UE can realize accurate time synchronization between the UE and the base station according to the time setting information received from the base station before, and the communication capability of the UE is improved.

It will be appreciated that, in order to implement the functions in the above embodiments, the access network device or the terminal device includes corresponding hardware structures and/or software modules that perform the respective functions. Those of skill in the art will readily appreciate that the various illustrative elements and method steps described in connection with the embodiments disclosed herein may be implemented as hardware or combinations of hardware and computer software. Whether a function is implemented as hardware or computer software driven hardware depends upon the particular application scenario and design constraints imposed on the solution.

Fig. 7 and 8 are schematic structural diagrams of possible communication devices according to an embodiment of the present application. These communication devices may be used to implement the functions of the access network device or the terminal device in the above method embodiments, so that the beneficial effects of the above method embodiments may also be implemented. In the embodiment of the application, the communication device may be an access network device or a terminal device, or may be a module (such as a chip) in the access network device or a module (such as a chip) in the terminal device.

The communication device 700 shown in fig. 7 includes a processing unit 710 and a transceiving unit 720. The communication device 700 is configured to implement the functions of the access network device or the terminal device in the above-described method embodiment. The transceiver unit 720 may be used to implement corresponding communication functions. The transceiver unit 720 may also be referred to as a communication interface or a communication unit. The processing unit 710 may be adapted to implement corresponding processing functions. Optionally, the communication apparatus 700 further includes a storage unit, where the storage unit may be configured to store instructions and/or data, and the processing unit 710 may read the instructions and/or data in the storage unit, so that the communication apparatus 700 implements actions of a terminal device (such as a UE) or an access network device (such as a base station) in the foregoing method embodiments.

When the communication apparatus 700 is configured to implement the functions of the terminal device in the above method embodiment, the transceiver unit 720 is configured to receive the time synchronization information from the access network device; and a processing unit 710, configured to perform time synchronization according to the current time of the terminal device, the receiving time of the pair of time information, and the pair of time information.

In a possible implementation method, the processing unit 710 is specifically configured to perform time synchronization according to the current time of the terminal device, the receiving time of the pair of time information, and the pair of time information when a preset condition is met; wherein, the preset conditions are as follows: the terminal equipment does not receive new time setting information from the access network equipment within a set time length; or the terminal equipment receives the first indication information and the new time setting information from the access network equipment within the set time length, wherein the first indication information indicates that the new time setting information does not meet the time setting precision requirement of the terminal equipment.

In a possible implementation method, the processing unit 710 is specifically configured to determine a difference between the current time of the terminal device and the time of receiving the pair of time information; determining a synchronization time based on the difference and the pair of time information; based on the synchronization time, time synchronization is performed.

In a possible implementation method, the pair of time information includes a clock frequency ratio and a clock deviation, the clock frequency ratio represents a clock frequency ratio between the terminal device and the access network device, and the clock deviation represents a clock deviation between the terminal device and the access network device; a processing unit 710, specifically configured to determine a ratio of the difference value to the clock frequency ratio; and determining the synchronous time according to the ratio, the clock deviation and the receiving time of the pair of time information.

In one possible implementation method, the pair of time information includes a clock frequency ratio, a transmission delay and a sending time of the pair of time information, where the clock frequency ratio indicates a clock frequency ratio between the terminal device and the access network device, and the transmission delay indicates a transmission delay between the terminal device and the access network device; a processing unit 710, specifically configured to determine a ratio of the difference value to the clock frequency ratio; the processing unit 710 is specifically configured to determine the synchronization time according to the ratio, the transmission delay, and the transmission time of the pair of time information.

In one possible implementation method, the pair of time information includes a clock deviation change rate, a clock frequency ratio and a clock deviation, the clock deviation change rate represents a time-dependent change amount of the clock deviation, the clock frequency ratio represents a clock frequency ratio between the terminal device and the access network device, and the clock deviation represents a clock deviation between the terminal device and the access network device; a processing unit 710, configured to determine a product of the clock skew rate and the difference, and determine a ratio of the product to the clock frequency ratio; the processing unit 710 is specifically configured to determine the synchronization time according to the ratio, the clock bias, and the current time of the terminal device.

In a possible implementation method, the transceiver unit 720 is further configured to receive the set duration from the access network device.

In one possible implementation, the set duration is preset.

In a possible implementation method, the transceiver unit 720 is further configured to send a time synchronization request message, where the time synchronization request message includes identification information of the terminal device and second indication information, and the second indication information indicates to provide a time synchronization service for the terminal device.

In a possible implementation method, the transceiver unit 720 is further configured to receive information for indicating to turn on the time setting function.

In a possible implementation method, the pair of time information includes a transmission delay and a sending time of the pair of time information, where the transmission delay represents a transmission delay between the terminal device and the access network device; the processing unit 710 is further configured to perform time synchronization according to the transmission delay and the sending time of the pair of time information before performing time synchronization according to the current time of the terminal device, the receiving time of the pair of time information, and the pair of time information.

When the communication apparatus 700 is configured to implement the function of the access network device in the above method embodiment, the processing unit 710 is configured to determine time synchronization information, where the time synchronization information includes a clock frequency ratio, and the clock frequency ratio represents a clock frequency ratio between the terminal device and the access network device; and the transceiver unit 720 is configured to send the pair of time information to the terminal device, where the pair of time information is used for local time synchronization of the terminal device.

In a possible implementation, the processing unit 710 is configured to determine a first clock bias at a first time and determine a second clock bias at a second time; and determining the clock deviation change rate according to a first difference value between the second clock deviation and the first clock deviation and a second difference value between the second time and the first time.

In a possible implementation method, the transceiver unit 720 is further configured to receive, before the processing unit 710 determines the time synchronization information, indication information, where the indication information indicates that the time synchronization service is provided for the terminal device.

When the communication apparatus 700 is configured to implement the function of the clock management network element (e.g. TSCTSF network element) in the above-described method embodiment, the transceiver unit 720 is configured to receive a time synchronization request message, where the time synchronization request message includes identification information and indication information of a terminal device, where the indication information indicates that a time synchronization service is provided for the terminal device; a processing unit 710, configured to select an access network device that provides a time synchronization service for the terminal device; the transceiver unit 720 is further configured to send a notification message to the policy control network element, where the notification message includes the identification information of the terminal device, the identification information of the access network device, and the indication information.

In a possible implementation method, the transceiver unit 720 is further configured to send a query message to a unified database network element, where the query message includes identification information of the terminal device, and the query message requests to obtain a policy control network element that provides services for the terminal device; and receiving the identification information of the strategy control network element from the unified database network element.

In a possible implementation method, the transceiver unit 720 is further configured to send a request message to the unified data management network element, where the request message includes identification information of the terminal device, and the request message is used to request to query whether to authorize providing a time synchronization service for the terminal device; and receiving a response message from the unified data management network element, wherein the response message indicates authorization to provide time setting service for the terminal equipment.

In a possible implementation method, the transceiver unit 720 is further configured to receive the pair of time request messages from the terminal device or the application function network element.

The more detailed description of the processing unit 710 and the transceiver unit 720 may be directly obtained by referring to the related description in the above method embodiments, which is not repeated herein.

The communication device 800 shown in fig. 8 includes a processor 810 and an interface circuit 820. Processor 810 and interface circuit 820 are coupled to each other. It is understood that the interface circuit 820 may be a transceiver or an input-output interface. Optionally, the communication device 800 may further comprise a memory 830 for storing instructions to be executed by the processor 810 or for storing input data required by the processor 810 to execute instructions or for storing data generated after the processor 810 executes instructions.

When the communication device 800 is used to implement the above-mentioned method embodiment, the processor 810 is used to implement the functions of the above-mentioned processing unit 710, and the interface circuit 820 is used to implement the functions of the above-mentioned transceiver unit 720.

It is to be appreciated that the processor in embodiments of the application may be a central processing unit (central processing unit, CPU), other general purpose processor, digital signal processor (digital signal processor, DSP), application specific integrated circuit (application specific integrated circuit, ASIC), field programmable gate array (field programmable gate array, FPGA) or other programmable logic device, transistor logic device, hardware components, or any combination thereof. The general purpose processor may be a microprocessor, but in the alternative, it may be any conventional processor.

The method steps in the embodiments of the present application may be implemented by hardware, or may be implemented by executing software instructions by a processor. The software instructions may be comprised of corresponding software modules that may be stored in random access memory, flash memory, read only memory, programmable read only memory, erasable programmable read only memory, electrically erasable programmable read only memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The processor and the storage medium may reside as discrete components in a base station or terminal.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, a base station, a UE, or other programmable device. The computer program or instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer program or instructions may be transmitted from one website site, computer, server, or data center to another website site, computer, server, or data center by wired or wireless means. The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that integrates one or more available media. The usable medium may be a magnetic medium, e.g., floppy disk, hard disk, tape; but also optical media such as digital video discs; but also semiconductor media such as solid state disks. The computer readable storage medium may be volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage medium.

In various embodiments of the application, where no special description or logic conflict exists, terms and/or descriptions between the various embodiments are consistent and may reference each other, and features of the various embodiments may be combined to form new embodiments based on their inherent logic.

In the present application, "at least one" means one or more, and "a plurality" means two or more. "and/or", describes an association relationship of an association object, and indicates that there may be three relationships, for example, a and/or B, and may indicate: a alone, a and B together, and B alone, wherein a, B may be singular or plural. In the text description of the present application, the character "/", generally indicates that the associated objects are an or relationship; in the formula of the present application, the character "/" indicates that the front and rear associated objects are a "division" relationship.

It will be appreciated that the various numerical numbers referred to in the embodiments of the present application are merely for ease of description and are not intended to limit the scope of the embodiments of the present application. The sequence number of each process does not mean the sequence of the execution sequence, and the execution sequence of each process should be determined according to the function and the internal logic.

Claims

1. A method of time synchronization, comprising:

the terminal equipment receives time setting information from the access network equipment;

and the terminal equipment performs time synchronization according to the current time of the terminal equipment, the receiving time of the time setting information and the time setting information.

2. The method of claim 1, wherein the terminal device time synchronizes based on a current time of the terminal device, a reception time of the pair of time information, and the pair of time information, comprising:

when a preset condition is met, the terminal equipment performs time synchronization according to the current time of the terminal equipment, the receiving time of the time setting information and the time setting information;

wherein, the preset conditions are as follows:

the terminal equipment does not receive new time setting information from the access network equipment within a set time length; or,

the terminal equipment receives first indication information and new time setting information from the access network equipment within a set time length, wherein the first indication information indicates that the new time setting information does not meet the time setting precision requirement of the terminal equipment.

3. The method according to claim 1 or 2, wherein after the terminal device receives the time tick information from the access network device, further comprising:

And the terminal equipment stores the receiving time of the time setting information and the time setting information.

4. A method according to any one of claims 1 to 3, wherein the terminal device time-synchronizes based on the current time of the terminal device, the time of receipt of the pair time information, and the pair time information, comprising:

the terminal equipment determines the difference value between the current time of the terminal equipment and the receiving time of the time setting information;

the terminal equipment determines synchronous time according to the difference value and the time setting information;

and the terminal equipment performs time synchronization according to the synchronization time.

5. The method of claim 4, wherein the pair of time information comprises a clock frequency ratio and a clock bias, the clock frequency ratio representing a clock frequency ratio between the terminal device and the access network device, the clock bias representing a clock bias between the terminal device and the access network device;

the terminal equipment determines the synchronous time according to the difference value and the time setting information, and the method comprises the following steps:

the terminal equipment determines the ratio of the difference value to the clock frequency ratio;

And the terminal equipment determines the synchronous time according to the ratio, the clock deviation and the time for receiving the time setting information.

6. The method of claim 4, wherein the pair of time information comprises a clock frequency ratio, a transmission delay, and a time of transmission of the pair of time information, the clock frequency ratio representing a clock frequency ratio between the terminal device and the access network device, the transmission delay representing a transmission delay between the terminal device and the access network device;

and the terminal equipment determines the synchronous time according to the ratio, the transmission delay and the sending time of the time setting information.

7. The method of claim 4, wherein the pair of time information includes a clock bias change rate, a clock frequency ratio, and a clock bias, the clock bias change rate representing an amount of change in clock bias over time, the clock frequency ratio representing a clock frequency ratio between the terminal device and the access network device, the clock bias representing a clock bias between the terminal device and the access network device;

the terminal equipment determines the product of the clock deviation change rate and the difference value, and determines the ratio of the product to the clock frequency ratio;

and the terminal equipment determines the synchronous time according to the ratio, the clock deviation and the current time of the terminal equipment.

8. The method of any one of claims 2, further comprising:

and the terminal equipment receives the set duration from the access network equipment.

9. The method of any one of claims 2, wherein the set duration is preset.

10. The method of any one of claims 1 to 9, further comprising:

the terminal equipment sends a time setting request message, wherein the time setting request message comprises identification information and second indication information of the terminal equipment, and the second indication information indicates that time setting service is provided for the terminal equipment.

11. The method of any one of claims 1 to 10, further comprising:

the terminal device receives information for indicating to start the time setting function.

12. The method according to any of claims 1 to 4, wherein the pair of time information comprises a transmission delay and a transmission time of the pair of time information, the transmission delay representing a transmission delay between the terminal device and the access network device;

the terminal device further comprises, before performing time synchronization according to the current time of the terminal device, the receiving time of the time synchronization information and the time synchronization information:

and the terminal equipment performs time synchronization according to the transmission time delay and the sending time of the time synchronization information.

13. A method of time synchronization, comprising:

the access network equipment determines time setting information, wherein the time setting information comprises a clock frequency ratio, and the clock frequency ratio represents the clock frequency ratio between the terminal equipment and the access network equipment;

the access network equipment sends the time setting information to the terminal equipment, and the time setting information is used for carrying out local time synchronization on the terminal equipment.

14. The method of claim 13, wherein the time tick information further comprises a clock bias, the clock bias representing a clock bias between the terminal device and the access network device.

15. The method of claim 13, wherein the time pair information further comprises a transmission delay and a time of transmission of the time pair information, the transmission delay representing a transmission delay between the terminal device and the access network device.

16. The method of claim 13, wherein the pair of time information further comprises a clock bias change rate and a clock bias, the clock bias change rate representing an amount of change in clock bias over time, the clock bias representing a clock bias between the terminal device and the access network device.

17. The method as recited in claim 16, further comprising:

the access network device determining a first clock bias at a first time and determining a second clock bias at a second time;

the access network equipment determines the clock deviation change rate according to a first difference value between the second clock deviation and the first clock deviation and a second difference value between the second time and the first time.

18. The method according to any of claims 13 to 17, wherein before the access network device determines the time tick information, further comprising:

the access network equipment receives indication information, and the indication information indicates that time setting service is provided for the terminal equipment.

19. A communication device comprising a processor and a memory coupled to the processor, the memory for storing program instructions, the processor for executing the program instructions to implement the method of any one of claims 1 to 12.

20. A communications device comprising a processor and a memory coupled to the processor, the memory for storing program instructions, the processor for executing the program instructions to implement the method of any of claims 13 to 18.

21. A computer program product comprising a computer program which, when executed by a communication device, implements the method of any of claims 1 to 18.

22. A computer readable storage medium, characterized in that the storage medium has stored therein a computer program or instructions which, when executed by a communication device, implement the method of any of claims 1 to 18.

23. A communication system comprising terminal equipment for performing the method of any of claims 1 to 12 and access network equipment for performing the method of any of claims 13 to 18.