Synchronization method, device and terminal

Abstract

The present disclosure discloses a synchronization method, apparatus and terminal related to the field of vehicle Internet technology, which is applied to a first terminal, and includes: receiving a first synchronization signaling sent by at least one second terminal when the first terminal is in a first synchronization state; and based on the first synchronization signaling, the first terminal performs a synchronization operation, and the first terminal switches to a second synchronization state.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This disclosure claims priority to a Chinese patent application filed in China on July 15, 2021, bearing application number 202110800778.0, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to the field of vehicle internet technology, and in particular to a synchronization method, device and terminal. [Background technology]

[0003] When vehicles are in complex environments such as urban canyons, crossings, viaducts, underground parking lots, and tunnels, they may not be able to receive satellite signals, making time synchronization based on satellite signals impossible. Meanwhile, the internal clocks of vehicular Internet devices have low accuracy and cannot meet the high-precision time synchronization requirements for a long period of time. Related technologies lack a method for implementing a correlation standard or a feasible sidelink synchronization signal. At the same time, the distributed architecture of vehicular Internet makes it difficult to synchronize and cooperate among a large number of terminals. Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure aims to provide a synchronization method, device, and terminal to solve the problem that the distributed architecture of the vehicular Internet in the related art makes it difficult for vehicular Internet terminals to synchronize and cooperate with each other. [Means for solving the problem]

[0005] In a first aspect, an embodiment of the present disclosure provides a synchronization method applied to a first terminal, the method comprising: receiving a first synchronization signaling transmitted by at least one second terminal when the first terminal is in a first synchronization state; Based on the first synchronization signaling, the first terminal performs a synchronization operation, and the first terminal switches to a second synchronization state.

[0006] Selectively receiving first synchronization signaling transmitted by at least one second terminal includes: receiving the first synchronization signaling carried by a physical sidelink shared channel (PSSCH).

[0007] Optionally, the method further comprises: receiving first indication information carried by a physical sidelink control channel (PSCCH), the first indication information being used to indicate whether the PSSCH carries the first synchronization signaling;

[0008] Optionally, based on the first synchronization signaling, the first terminal performs a synchronization operation, and the first terminal switches to a second synchronization state; When the received power of at least one PSSCH carrying the first synchronization signaling is equal to or greater than a first threshold, the first terminal performs a synchronization operation, including switching the first terminal to the second synchronization state.

[0009] Optionally, the method further comprises: When the first terminal is in a desynchronization state, the first terminal receives second synchronization signaling carried by a physical sidelink broadcast channel (PSBCH) transmitted by at least one third terminal, and switches to the first synchronization state or maintains the desynchronization state.

[0010] Optionally, the method further comprises: If the first terminal is in the second synchronization state, determining a first portion of the synchronization level of the first terminal as a first numerical value.

[0011] Optionally, the method further comprises: If a synchronization source of the first terminal is a GNSS signal, determining a second portion of the synchronization level of the first terminal as a second numerical value; and / or When the value of the second part of the synchronization level attached to the first synchronization signaling transmitted by the synchronization source of the first terminal is n, determining the second part of the synchronization level of the first terminal as n+1; Here, n≧0 and n is an integer.

[0012] Optionally, the method further comprises: receiving first synchronization signaling carried by at least one PSSCH when the first terminal is in the second synchronization state; The first terminal performs a synchronization operation based on first synchronization signaling carried by the PSSCH; Here, the received power of at least one of the PSSCHs is equal to or greater than a second threshold.

[0013] Optionally, the first synchronization signaling comprises: a first part of the synchronization level; a second part of the synchronization level; a sidelink radio frame number; a sidelink subframe number; and World Coordinated Time, a first timing offset value, which is a timing offset of the terminal transmitting the first synchronization signaling relative to a reference time; An identifier (Identity Document, ID) of the terminal transmitting the first synchronization signaling; a first timing adjustment value that is an adjustment amount of a synchronization period between a terminal transmitting the first synchronization signaling and its synchronization source; The first synchronization signaling signaling includes at least one of a second timing offset value, which is a timing offset between the terminal transmitting the first synchronization signaling and another terminal, and a terminal ID corresponding to the second timing offset value.

[0014] Optionally, the first terminal performs a synchronization operation, determining, based on the received primary synchronization signaling, a third timing offset value of the first terminal relative to the terminal transmitting the primary synchronization signaling; determining a second timing adjustment value of the first terminal when receiving the first synchronization signaling; determining an actual timing deviation between the first terminal and a terminal transmitting a first synchronization signaling based on the second timing offset value, the first timing adjustment value, the second timing adjustment value, and the third timing offset value; The first terminal performs a synchronization operation based on the actual timing deviation.

[0015] Optionally, determining an actual timing deviation between the first terminal and a terminal transmitting first synchronization signaling based on the second timing offset value, the first timing adjustment value, the second timing adjustment value, and the third timing offset value includes: Calculating an actual timing deviation between the first terminal and a terminal transmitting a first synchronization signaling according to the following equation (1):

number

[0016] Optionally, the first terminal performs a synchronization operation, determining, based on the received primary synchronization signaling, a third timing offset value of the first terminal relative to the terminal transmitting the primary synchronization signaling; obtaining the first timing offset value and the first timing adjustment value in the first synchronization signaling; determining an offset value of the first terminal relative to a reference time based on the third timing offset value, the first timing offset value, and the first timing adjustment value; The first terminal performs a synchronization operation based on the offset value of the first terminal relative to a reference time.

[0017] Optionally, the method further comprises: When the first terminal is in the second synchronization state, if a first condition is satisfied, the first terminal performs a synchronization operation, and the first terminal switches to the first synchronization state; Here, the first condition is: No GNSS signal has been received within the first period of time; and not receiving a first synchronization signaling carried by the PSSCH within a second time period; receiving second synchronization signaling carried by at least one PSBCH within a third time period, and the received power of the at least one PSBCH being greater than or equal to a third threshold;

[0018] Optionally, the method further comprises: When the first terminal is in the first synchronization state or the second synchronization state, if the first terminal does not receive a GNSS signal within a fourth time, does not receive first synchronization signaling carried by a PSSCH within a fifth time, and does not receive second synchronization signaling carried by a PSBCH within a sixth time, the first terminal switches to a desynchronization state.

[0019] Optionally, the method further comprises: When the first terminal is in a desynchronization state or the first synchronization state, upon receiving a GNSS signal, the first terminal synchronizes with the GNSS signal and switches to the second synchronization state; Alternatively, when the first terminal is in the second synchronization state, upon receiving a GNSS signal, the first terminal synchronizes with the GNSS signal.

[0020] In a second aspect, an embodiment of the present disclosure further provides a terminal, the terminal being a first terminal, including a transceiver, a memory, a processor, and a computer program stored in the memory and executable by the processor, wherein when the processor executes the computer program, the synchronization method described in the first aspect is realized.

[0021] In a third aspect, an embodiment of the present disclosure further provides a synchronization device adapted to a first terminal, comprising: The synchronization device a first receiving module configured to receive first synchronization signaling transmitted by at least one second terminal when the first terminal is in a first synchronization state; and a first synchronization module configured to, based on the first synchronization signaling, the first terminal perform a synchronization operation, and the first terminal switch to a second synchronization state.

[0022] In a fourth aspect, an embodiment of the present disclosure further provides a computer-readable storage medium having a computer program stored thereon, the computer program realizing the synchronization method according to the first aspect when executed by a processor. [Effects of the Invention]

[0023] The above technical solutions of the present disclosure have at least the following beneficial effects: According to the synchronization method of the embodiment of the present disclosure, first, when the first terminal is in a first synchronization state, it receives a first synchronization signaling sent by at least one second terminal, and then, based on the first synchronization signaling, the first terminal performs a synchronization operation and switches to a second synchronization state. In this way, the synchronization operation of the first terminal based on the received first synchronization signaling enables the first terminal to switch from the first synchronization state to the second synchronization state, which not only solves the problem of difficulty in synchronization cooperation between vehicle Internet terminals in a distributed architecture of vehicle Internet, but also improves the synchronization accuracy of the first terminal. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a flow diagram of a synchronization method according to an embodiment of the present disclosure. [Figure 2] FIG. 10 is a schematic diagram of an adjustment by timing adjustment within a gap transmitting synchronization signaling according to an embodiment of the present disclosure. [Figure 3] FIG. 2 is a schematic diagram of transmission of synchronization signaling in an embodiment of the present disclosure. [Figure 4] FIG. 10 is a schematic diagram of switching between a desynchronization state, a first synchronization state, and a second synchronization state of a first terminal in an embodiment of the present disclosure. [Figure 5] FIG. 2 is a schematic diagram of a first scene applying a synchronization method according to an embodiment of the present disclosure. [Figure 6] FIG. 10 is a schematic diagram of a second scene applying a synchronization method according to an embodiment of the present disclosure. [Figure 7] 1 is a structural schematic diagram of a synchronization device according to an embodiment of the present disclosure; [Figure 8] FIG. 1 is a structural schematic diagram of a terminal according to an embodiment of the present disclosure; DETAILED DESCRIPTION OF THE INVENTION

[0025] To clarify the technical problems, technical solutions, and advantages of the present disclosure, the following detailed description will be provided with reference to drawings and specific examples. In the following description, details such as specific configurations and components are described to facilitate understanding of the present disclosure. Therefore, it will be apparent to those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. Note that known functions and configurations are omitted for clarity and conciseness.

[0026] It should be understood that references throughout the specification to "one embodiment" or "one embodiment" mean that a particular feature, structure, or characteristic associated with that embodiment is included in at least one embodiment of the present disclosure. Thus, the appearances of "in one embodiment" or "in one embodiment" in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, these particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0027] In various embodiments of the present disclosure, the order of the numbers of the following processes does not imply the order of execution, and the order of execution of each process should be determined by its function and internal logic, and does not constitute any limitation on the implementation process of the embodiments of the present disclosure.

[0028] In the embodiments of the present disclosure, "B corresponding to A" indicates that B is related to A, and it is understood that B can be determined based on A. It is also understood that determining B based on A does not mean determining B based only on A, but that B can also be determined based on A and / or other information.

[0029] When describing the embodiments of the present disclosure, first, the concepts used in the following description will be explained.

[0030] High-precision time synchronization is a key technology for the Internet of Vehicles. It not only affects vehicle safety during operation, but also the safety of other traffic participants and the development of various Internet of Vehicles applications. The main synchronization sources for Internet of Vehicles devices include the Global Navigation Satellite System (GNSS), 5th Generation Mobile Communication Technology (5G) base stations (gNBs) / eNBs, other Internet of Vehicles devices, and their internal clocks. However, when vehicles are in complex environments such as urban canyons, crossings, viaducts, underground parking lots, and tunnels, satellite signals may not be received, making time synchronization via satellite signals impossible. Meanwhile, the internal clocks of Internet of Vehicles devices have low accuracy and cannot meet the high-precision time synchronization requirements for a long period of time. Therefore, unsynchronized Internet of Vehicles devices must obtain time synchronization signals from other synchronized Internet of Vehicles devices. Currently, the Internet of Vehicles mainly uses Orthogonal Frequency Division Multiplexing (OFDM) modulation technology for communication, and OFDM systems generally require precise time synchronization to maintain orthogonality between carriers.

[0031] Currently, the synchronization scheme defined by the 3rd Generation Partnership Project (3GPP®) mainly includes two types of synchronization signals: 1) a Sidelink Synchronization Signal (SLSS) used for time and frequency synchronization, and 2) a Sidelink Master Information Block (MIB-SL) used to provide other information. The SLSS includes a Primary Sidelink Synchronization Signal (PSSS) and a Secondary Sidelink Synchronization Signal (SSSS).

[0032] The MIB-SL is transmitted via the Physical Sidelink Broadcast Channel (PSBCH) and carries the following information: an inCoverage indicator indicating whether the synchronization signal transmitting device is within the coverage area of ​​the cell, and the corresponding frame number and subframe number (directFrameNumber and directSubFrameNumber) when connected to the coverage area. When transmitting the SLSS and MIB-SL, the user equipment (UE) must select the parameters to determine the corresponding subframe. To facilitate the processing of subframes for service transmission in the resource pool, the physical subframe determined based on the system frame number (SFN) must be mapped to a logical subframe in the form of a synchronization bitmap, and the logical subframe must be obtained by excluding the following three types of subframes (1) to (3) from the physical subframe.

[0033] 1) All downlink (DL) subframes and special subframes when the PC5 port and Uu port (both PC5 port and Uu port are communication interfaces) share a time division duplex (TDD) carrier. 2) Synchronization subframes for transmitting SLSS and PSBCH (the synchronization period is specified as 160 ms in the protocol). 3) Reserved subframes.

[0034] In the SFN period (10240 ms), after excluding 1) and 2), the subframe indices of the remaining subframes are arranged in ascending order.

number

[0035] N reserved =(10240-N slss -N dssf )mod L bitmap

[0036] where N reserved is the number of reserved subframes, and L bitmap is the bit mapping length configured by higher layers. Then, the reserved subframes are evenly distributed across the SFN according to the following method.

[0037]

number

[0038] where m=0,…,N reserved It is -1.

[0039] By excluding these three types of subframes, the remaining subframes in the SFN / Direct Frame Number (DFN) cycle can be used to transmit V2X (Vehicle-to-Everything) services. The resource pool configuration indicates logical subframes in a bitmap manner using a time domain indication method, and the protocol specifies that the bitmap length can be any of 16, 20, and 100.

[0040] In the related art, if the bitmap length is specified as 100, the number of reserved subframes is 40 and the period is 256 ms. At the same time, roadside devices can transmit sidelink synchronization signals in subframes that are not configured for V2X message transmission according to their own capabilities, where the correlation standard indicates that these subframes include at least reserved subframes.

[0041] The related art lacks a method for implementing a correlation standard or a workable sidelink synchronization signal. At the same time, the distributed architecture of the Internet of Vehicles makes synchronous cooperation among a large number of terminals difficult.

[0042] The present disclosure provides a synchronization method, apparatus and terminal for solving the above problems.

[0043] As shown in FIG. 1, the synchronization method according to the embodiment of the present disclosure is performed by a first terminal, and includes the following steps 101 to 102.

[0044] In step 101, when the first terminal is in a first synchronization state, it receives a first synchronization signaling sent by at least one second terminal.

[0045] In step 102, based on the first synchronization signaling, the first terminal performs a synchronization operation, and the first terminal switches to a second synchronization state.

[0046] Here, the first terminal and the second terminal are both vehicle Internet devices. For example, the first terminal is an on-board unit (OBU), and the second terminal is a road side unit (RSU). The first synchronization signaling in the embodiment of the present disclosure may be a synchronization message. The first synchronization state and the second synchronization state may be synchronization states of the terminals with different synchronization accuracies. For example, the accuracy of the first synchronization state may be lower than the accuracy of the second synchronization state.

[0047] According to the synchronization method of the embodiment of the present disclosure, first, when the first terminal is in a first synchronization state, it receives a first synchronization signaling sent by at least one second terminal; then, based on the first synchronization signaling, the first terminal performs a synchronization operation and switches to a second synchronization state. In this way, the synchronization operation of the first terminal based on the received first synchronization signaling enables the first terminal to switch from the first synchronization state to the second synchronization state, thereby realizing time synchronization between vehicular Internets in an area not covered by satellite signals, and not only solving the problem of difficulty in synchronous cooperation between vehicular Internet terminals in a distributed vehicular Internet architecture, but also improving the synchronization accuracy of the terminals.

[0048] In one possible implementation, receiving the first synchronization signaling transmitted by at least one second terminal in step 101 includes: receiving the first synchronization signaling carried by a Physical Sidelink Shared Channel (PSSCH).

[0049] The method further comprises: receiving first indication information carried by a Physical Sidelink Control Channel (PSCCH), the first indication information being used to indicate whether the PSCCH carries the first synchronization signaling;

[0050] That is, in the embodiment of the present disclosure, the following two methods can be adopted for transmitting the primary synchronization signaling: In one method, the primary synchronization signaling is carried on the PSSCH; In another method, the primary synchronization signaling is carried on the PSSCH, and the first indication information is carried on the PSCCH, where the first indication information is used to indicate whether the PSSCH carries the primary synchronization signaling.

[0051] Specifically, the correlation standard specifies that Sidelink Control Information (SCI) adopts SCI format 1, and currently SCI format 1 has at least 7 remaining padding bits. Therefore, in the embodiment of the present disclosure, any one of the padding bits of the SCI in the PSCCH is selectively used to indicate whether the PSSCH carries primary synchronization signaling. For example, if the value of the bit for indicating whether the PSSCH carries primary synchronization signaling is 1, it indicates that the PSSCH indicated by the PSCCH carries primary synchronization signaling.

[0052] In one possible implementation, the first terminal performs a synchronization operation based on the first synchronization signaling in step 102, and the first terminal switches to a second synchronization state. When the received power of at least one PSSCH carrying the first synchronization signaling is equal to or greater than a first threshold, the first terminal performs a synchronization operation, including switching the first terminal to the second synchronization state.

[0053] In this optional implementation, when the first terminal performs a synchronization operation, it first determines a synchronization source for the first terminal based on first synchronization signaling carried by at least one received PSSCH, and then synchronizes with the currently determined synchronization source. Specifically, the synchronization source for the first terminal can be determined based on the received power of at least one PSSCH carrying the received first synchronization signaling. For example, the received power of the PSSCH carrying the first synchronization signaling transmitted by the synchronization source of the first terminal is greater than a first threshold. Thus, from the multiple PSSCHs carrying the received first synchronization signaling, multiple PSSCHs with received power greater than the first threshold are selected, and the synchronization source for the first terminal is determined based on the selected PSSCHs. Furthermore, from the multiple PSSCHs carrying the selected first synchronization signaling, the terminal transmitting the PSSCH with the highest synchronization level is selected as the synchronization source for the first terminal.

[0054] That is, when the first terminal performs a synchronization operation, specifically, the first terminal synchronizes with a first PSSCH, where the first PSSCH is a PSSCH carrying first synchronization signaling, the received power of the first PSSCH is equal to or greater than a first threshold, and the synchronization level of the first PSSCH is the highest among a plurality of PSSCHs whose received power is equal to or greater than the first threshold.

[0055] Furthermore, in one alternative implementation, the method further comprises: When the first terminal is in a desynchronization state, the first terminal receives second synchronization signaling carried by a physical sidelink broadcast channel (PSBCH) transmitted by at least one third terminal, and switches to the first synchronization state or maintains the desynchronization state.

[0056] Here, in this optional implementation mode, when the first terminal is in a desynchronized state, it does not receive GNSS signals, but upon receiving second synchronization signaling carried by the PSBCH, the first terminal performs a synchronization operation based on the second synchronization signaling carried by the PSBCH, and switches to the first synchronization state or maintains the desynchronized state.

[0057] Here, the second synchronization signaling is used to indicate the synchronization level of the third terminal, and the second synchronization signaling includes indication information indicating whether the third terminal is within the GNSS coverage area and a sidelink synchronization signal index.

[0058] The process for realizing this selectable implementation mode will be specifically described below.

[0059] When the first terminal is in a desynchronization state and is not receiving a GNSS signal, upon receiving second synchronization signaling carried by the PSBCH, Determine whether the received power of the PSBCH carrying the second synchronization signaling is greater than or equal to a fourth threshold, and if it is greater than or equal to the fourth threshold, the first terminal performs a synchronization operation based on the PSBCH carrying the second synchronization signaling, and switches from a desynchronization state to a first synchronization state, and if it is less than the fourth threshold, the first terminal maintains the desynchronization state.

[0060] Specifically, in the process in which the first terminal performs a synchronization operation, the first terminal synchronizes with the third terminal transmitting a first PSBCH, where the first PSBCH is a PSBCH carrying a second synchronization signaling, the received power of the first PSBCH is equal to or greater than a fourth threshold, and the synchronization level of the first PSBCH is the highest among a plurality of PSBCHs whose received power is equal to or greater than the fourth threshold.

[0061] It should be noted that the first synchronization signaling and the second synchronization signaling in the embodiments of the present disclosure are not a specific synchronization signaling, but two different types of signaling.

[0062] Furthermore, when the first terminal is in a desynchronized state, if the first terminal does not receive the secondary synchronization signaling carried by the GNSS signal and the PSBCH, the first terminal maintains the desynchronized state.

[0063] Furthermore, if the synchronization level of the terminal transmitting the secondary synchronization signaling carried by the PSBCH is the first synchronization level or the second synchronization level, the terminal transmits the PSBCH carrying the secondary synchronization signaling on a reserved subframe. For example, 40 reserved subframes in one radio frame are numbered in chronological order, and the odd-numbered reserved subframes transmit the secondary synchronization signaling with a synchronization level of 1, and the even-numbered reserved subframes transmit the secondary synchronization signaling with a synchronization level of 2.

[0064] In one alternative implementation, the method further comprises: If the first terminal is in the second synchronization state, determining a first portion of the synchronization level of the first terminal as a first numerical value.

[0065] Here, in this optional implementation, the first terminal may be an RSU, that is, when the RSU enters the second synchronization state, the first part of the synchronization level of the RSU becomes a first numerical value, and specifically, the first numerical value may be 1.

[0066] In this case, in the second synchronization signaling carried by the PSBCH transmitted by the first terminal, the inCoverage indicator is a third numerical value and the SLSS ID is a fourth numerical value, for example, the third numerical value may be 1 and the fourth numerical value may be 0.

[0067] Here, inCoverage is the indication information in the secondary synchronization signaling, and SLSS ID is the sidelink synchronization signal index.

[0068] Furthermore, in another alternative implementation, the method further comprises: If the synchronization source of the first terminal is a GNSS signal, determining a second portion of the synchronization level of the first terminal as a second numerical value (for example, the second numerical value is 0). and / or When the value of the second part of the synchronization level attached to the first synchronization signaling transmitted by the synchronization source of the first terminal is n, determining the second part of the synchronization level of the first terminal as n+1; Here, n≧0 and n is an integer.

[0069] For example, the format of the synchronization level of the first terminal is "ab," where a is the first part of the synchronization level and b is the second part of the synchronization level. Specifically, for example, when the first terminal is in the second synchronization state and the synchronization source is a GNSS signal, the synchronization level of the first terminal can be expressed as "1.0." When the first terminal is in the second synchronization state and the second part of the synchronization level attached to the first synchronization signaling transmitted by the synchronization source is 2, the synchronization level of the first terminal can be expressed as "1.3."

[0070] Note that when the first terminal (e.g., the first terminal is an RSU) is in the first synchronization state, the synchronization level of the transmitting terminal indicated by the secondary synchronization signaling carried by the PSBCH received by the first terminal is m, and when the first terminal is synchronized with the terminal transmitting the PSBCH carrying the second synchronization signaling, the synchronization level of the first terminal is m+1. For example, when m is 1, the synchronization level of the first terminal is 2, and the synchronization level indicated by the secondary synchronization signaling carried by the PSBCH transmitted by the first terminal is 2. Specifically, in the secondary synchronization signaling carried by the PSBCH transmitted by the first terminal, the inCoverage indicator is a fifth numerical value, and the SLSS ID is a sixth numerical value, for example, the fifth numerical value is 0. When m is 2, the synchronization level of the first terminal is 3, and the first terminal does not transmit the secondary synchronization signaling carried by the PSBCH.

[0071] Also, when the first terminal is an OBU, the synchronization level of the first terminal is defined as follows:

[0072] If the first terminal does not transmit synchronization signaling, the first terminal does not have a synchronization level; When the first terminal transmits the second synchronization signaling carried by the PSBCH, if the synchronization source of the first terminal is a GNSS signal, the synchronization level of the first terminal becomes the first synchronization level (i.e., synchronization level 1). In this case, the inCoverage indicator in the second synchronization signaling carried by the PSBCH transmitted by the first terminal becomes 1, and the SLSS ID becomes 0. When the first terminal transmits the second synchronization signaling carried by the PSBCH, if the synchronization source of the first terminal is an RSU device, or if the first part of the synchronization level of the synchronization source indicated by the second synchronization signaling carried by the PSBCH transmitted by the synchronization source is 1 or the synchronization level is 1, the synchronization level of the first terminal becomes the second synchronization level (i.e., synchronization level 2), in this case, the inCoverage indicator in the second synchronization signaling carried by the PSBCH transmitted by the first terminal becomes 0, and the SLSS ID becomes 0; If the synchronization level indicated by the second synchronization signaling carried by the PSBCH received by the first terminal is the second synchronization level, the synchronization level of the first terminal becomes the third synchronization level (i.e., synchronization level 3), in which case the first terminal does not transmit synchronization signaling.

[0073] In one alternative implementation, the method further comprises: receiving first synchronization signaling carried by at least one PSSCH when the first terminal is in the second synchronization state; The first terminal performs a synchronization operation based on first synchronization signaling carried by the PSSCH; Here, the received power of at least one of the PSSCHs is equal to or greater than a second threshold.

[0074] Specifically, in this optional implementation, the first terminal performs a synchronization operation based on the first synchronization signaling carried by the PSSCH, specifically: The method includes determining a synchronization source for the first terminal based on first synchronization signaling carried by at least one received PSSCH, and the first terminal synchronizing with the currently determined synchronization source. Specifically, the synchronization source for the first terminal can be determined based on the received power of at least one PSSCH carrying the received first synchronization signaling. For example, the received power of the PSSCH carrying the first synchronization signaling transmitted by the synchronization source of the first terminal is equal to or greater than a second threshold. Thus, from the plurality of PSSCHs carrying the received first synchronization signaling, multiple PSSCHs having received powers greater than the second threshold are selected, and the synchronization source for the first terminal is determined based on the selected PSSCHs. Furthermore, from the plurality of PSSCHs carrying the selected first synchronization signaling, the terminal transmitting the PSSCH with the highest synchronization level is selected as the synchronization source for the first terminal.

[0075] That is, when the first terminal performs a synchronization operation, specifically, the first terminal synchronizes with the second PSSCH, where the second PSSCH is a PSSCH carrying a first synchronization signaling, the received power of the second PSSCH is equal to or greater than a second threshold, and the synchronization level of the second PSSCH is the highest among a plurality of PSSCHs whose received power is equal to or greater than the second threshold.

[0076] That is, when the first terminal is in the second synchronization state, the first terminal performs a synchronization operation based on the first synchronization signaling carried by the PSSCH, thereby maintaining the first terminal in the second synchronization state.

[0077] In one alternative implementation, the first synchronization signaling comprises: a first part of the synchronization level; a second part of the synchronization level; a sidelink radio frame number; a sidelink subframe number; and Universal Time Coordinated (UTC) and a first timing offset value, which is a timing offset of the terminal transmitting the first synchronization signaling relative to a reference time; an identifier ID of a terminal transmitting the first synchronization signaling; a first timing adjustment value that is an adjustment amount of a synchronization period between a terminal transmitting the first synchronization signaling and its synchronization source; The first synchronization signaling signaling includes at least one of a second timing offset value, which is a timing offset between the terminal transmitting the first synchronization signaling and another terminal, and a terminal ID corresponding to the second timing offset value.

[0078] In this optional implementation mode, the first timing adjustment value is an adjustment made by the terminal transmitting the first synchronization signaling within the gap between transmissions of the first synchronization signaling, and as shown in Figure 2, a schematic diagram of the time series relationship between transmission of the first synchronization signaling and timing adjustment is shown.

[0079] Here, the radio frame and subframe number corresponding to the primary synchronization signaling are used to achieve millisecond-level synchronization.

[0080] Exemplarily, the format of the first synchronization signaling may be as follows:

[0081] [Table 1]

[0082] Here, in the above format, the content of the synchronization level field is the first part and / or the second part of the synchronization level, the content of the radio frame number and subframe number or UTC field is at least one of a sidelink radio frame number, a sidelink subframe number, and UTC, the content of the ID field is the ID of the terminal transmitting the first synchronization signaling, and the content of the inter-RSU timing offset and corresponding RSU ID field is a second timing offset value and a terminal ID corresponding to the second timing offset value.

[0083] The first timing adjustment value is the timing adjustment amount when the terminal transmitting the first synchronization signaling synchronizes with the synchronization source within the previous synchronization period, where the previous synchronization period is the synchronization period before transmitting the first synchronization signaling, and the second timing offset value and the terminal ID corresponding to the second timing offset value are the temporal timing offset of the synchronization signaling transmitted from the other N terminals monitored by the terminal transmitting the first synchronization signaling, relative to the terminal transmitting the first synchronization signaling, and the corresponding N RSU IDs.

[0084] In one specific implementation, the first terminal performing the synchronization operation comprises: determining, based on the received primary synchronization signaling, a third timing offset value of the first terminal relative to the terminal transmitting the primary synchronization signaling; determining a second timing adjustment value of the first terminal when receiving the first synchronization signaling; determining an actual timing deviation between the first terminal and a terminal transmitting a first synchronization signaling based on the second timing offset value, the first timing adjustment value, the second timing adjustment value, and the third timing offset value; The first terminal performs a synchronization operation based on the actual timing deviation.

[0085] Here, in this specific implementation, the first terminal may be an RSU.

[0086] More specifically, determining an actual timing deviation between the first terminal and a terminal transmitting first synchronization signaling based on the second timing offset value, the first timing adjustment value, the second timing adjustment value, and the third timing offset value includes: Calculating an actual timing deviation between the first terminal and a terminal transmitting a first synchronization signaling according to the following equation (1):

number

[0087] For example, the process of transmitting and measuring timing offset between RSUs is described as follows.

[0088] As shown in FIG. 3, when the propagation distance between RSUx (i.e., Tx in FIG. 3) and RSUy (i.e., Ty in FIG. 3) is L xy At time i-1, the timing offsets of RSUx and RSUy relative to the reference clock are T x,i-1 and T y,i-1 and RSUy measures the relative timing offset by receiving the first synchronization signaling transmitted from RSUx to be Ta yx,i-1 and RSUx and RSUy are time-adjusted by the timing adjustment Td x,i-1 , Td y,i-1After this, at time i, the timing offsets of RSUx and RSUy relative to the reference clock are T x,i and T y,i RSUy transmits the primary synchronization signaling, and RSUx receives the primary synchronization signaling transmitted from RSUy and measures the relative timing offset as Ta xy,i In this case,

number

[0089] In practical applications, RSUy and RSUx are relatively stationary, and Ta xy,i and Ta yx,i-1 The measurement of T is practically close. x,i =T x,i-1 -Td x,i-1 and T y,i =T y,i-1 -Td y,i-1 and T x,i-1 =T x,i +Td x,i-1 and T y,i-1 =T y,i +Td y,i-1 Therefore, T x,i and T y,i The actual deviation is given by the following equation (2):

[0090]

number

[0091] In another embodiment, the first terminal performing a synchronization operation comprises: determining, based on the received primary synchronization signaling, a third timing offset value of the first terminal relative to the terminal transmitting the primary synchronization signaling; a first terminal determining a second timing adjustment value of the first terminal when receiving the first synchronization signaling; Calculating an actual timing deviation between the first terminal and the terminal transmitting the first synchronization signaling based on a third timing offset value, a second timing adjustment value, and a difference value between the second timing offset value and the first timing adjustment value.

[0092] According to this embodiment, if a terminal transmitting a first synchronization signaling does not transmit a second timing offset value and a first timing adjustment value, but transmits a difference value between the second timing offset value and the first timing adjustment value, the first terminal can still obtain an actual timing deviation from the terminal transmitting the first synchronization signaling.

[0093] Specifically, the actual timing deviation is calculated using the following equation (3).

[0094]

number

[0095] Here, Ta' yx is a difference value between the second timing offset value and the first timing adjustment value, x is a first terminal, y is a terminal that transmits the first synchronization signaling, and Rt xy is the actual timing deviation between the first terminal and the terminal transmitting the first synchronization signaling, and Ta xy is the third timing offset value, and Td x is the second timing adjustment value, and Δt yx is the timing measurement error of the terminal transmitting the first synchronization signaling, and Δt xy is the timing measurement error of the first terminal.

[0096] In addition,

number

number

number

[0097] According to the above embodiment, if a terminal transmitting a first synchronization signaling does not transmit a second timing offset value and a first timing adjustment value, but transmits a difference value between the second timing offset value and the first timing adjustment value, the first terminal can still obtain an actual timing deviation from the terminal transmitting the first synchronization signaling.

[0098] Furthermore, each RSU maintains synchronization with its synchronization source RSU, and due to measurement errors and crystal vibration errors, the synchronization source usually has a certain deviation from the reference time. In the process of maintaining synchronization with the synchronization source, misalignment from the reference clock may occur, resulting in the accumulation of multi-stage synchronization adjustment errors. If the deviation of the RSU from the reference time can be directly obtained, the probability of misalignment can be effectively reduced and the accumulation of multi-stage synchronization adjustment errors can be reduced.

[0099] Specifically, T x is the relative offset of the RSUx timing relative to the reference time, and Rt yx is the actual deviation of RSUy relative to RSUx, the relative offset value of RSUy relative to the reference time, Rty is expressed as the following equation (4).

[0100]

number

[0101] The above embodiment eliminates the propagation delay between RSUs to achieve synchronization between RSUs, and each RSU periodically broadcasts an offset relative to the reference time, allowing the RSU to achieve timing adjustment based on the reference time, effectively reducing the probability of misalignment and reducing the accumulation of multi-stage synchronization adjustment errors.

[0102] In one alternative embodiment, the first terminal performing the synchronization operation comprises: determining, based on the received primary synchronization signaling, a third timing offset value of the first terminal relative to the terminal transmitting the primary synchronization signaling; obtaining the first timing offset value and the first timing adjustment value in the first synchronization signaling; determining an offset value of the first terminal relative to a reference time based on the third timing offset value, the first timing offset value, and the first timing adjustment value; The first terminal performs a synchronization operation based on the offset value of the first terminal relative to a reference time.

[0103] In this embodiment, the first terminal is an OBU. By adopting the embodiment of the present disclosure, the OBU constantly adjusts the local time based on the offset value relative to the reference time, thereby achieving synchronization of the OBU.

[0104] Also, if the first terminal is an OBU, and the first synchronization signaling transmitted by the RSU via the PSSCH includes only a synchronization level, UTC, a first timing offset value, and a first timing adjustment value, the OBU device synchronizes with the PSSCH with the highest synchronization level. Assuming that T is the first timing offset value and Td is the first timing adjustment value, when the OBU device receives the first synchronization signaling carried by the PSSCH and measures the timing offset Rt relative to the synchronization source RSU, the offset of the OBU's UTC time is T+Td+Rt. The OBU then adjusts its local time based on the offset value relative to UTC time to complete synchronization.

[0105] Furthermore, in one alternative implementation, the method further comprises: When the first terminal is in the second synchronization state, if a first condition is satisfied, the first terminal performs a synchronization operation, and the first terminal switches to the first synchronization state; Here, the first condition is: No GNSS signal has been received within the first period of time; and not receiving a first synchronization signaling carried by the PSSCH within a second time period; receiving second synchronization signaling carried by at least one PSBCH within a third time period, and the received power of the at least one PSBCH being greater than or equal to a third threshold;

[0106] Specifically, in the process in which the first terminal performs a synchronization operation in the embodiment of the present disclosure, the first terminal synchronizes with the terminal transmitting the second PSBCH, where the second PSBCH is a PSBCH carrying second synchronization signaling, the received power of the second PSBCH is equal to or greater than a third threshold, and the synchronization level of the second PSBCH is the highest among the multiple PSBCHs whose received power is equal to or greater than the third threshold.

[0107] Furthermore, in one alternative implementation, the method further comprises: When the first terminal is in the first synchronization state or the second synchronization state, if the first terminal does not receive a GNSS signal within a fourth time, does not receive first synchronization signaling carried by a PSSCH within a fifth time, and does not receive second synchronization signaling carried by a PSBCH within a sixth time, the first terminal switches to a desynchronization state.

[0108] In this optional implementation, if the first terminal does not receive a GNSS signal, the first synchronization signaling carried by the PSSCH, and the second synchronization signaling carried by the PSBCH, the first terminal determines that synchronization has timed out and the first terminal enters a desynchronization state.

[0109] Furthermore, in one alternative implementation, the method further comprises: When the first terminal is in a desynchronization state or the first synchronization state, upon receiving a GNSS signal, the first terminal synchronizes with the GNSS signal and switches to the second synchronization state; Alternatively, when the first terminal is in the second synchronization state, upon receiving a GNSS signal, the first terminal synchronizes with the GNSS signal.

[0110] That is, when the synchronization source of the first terminal is a GNSS signal, the first terminal directly enters the second synchronization state, or the first terminal synchronizes with the GNSS signal in the second synchronization state and maintains the second synchronization state.

[0111] Furthermore, in one alternative implementation, when the first terminal is in a first synchronization state, if a second condition is met, the first terminal performs a synchronization operation; Here, the second condition is: No GNSS signal has been received within the seventh hour; Not receiving a first synchronization signaling carried by the PSSCH within an eighth time period; receiving second synchronization signaling carried by at least one PSBCH within a ninth time period, and the received power of the at least one PSBCH being greater than or equal to a fifth threshold;

[0112] Similarly, in the process in which the first terminal performs a synchronization operation in the embodiment of the present disclosure, the first terminal synchronizes with the terminal transmitting the third PSBCH, where the third PSBCH is a PSBCH carrying a second synchronization signaling, the received power of the third PSBCH is equal to or greater than a third threshold, and the synchronization level of the third PSBCH is the highest among the multiple PSBCHs whose received power is equal to or greater than a fifth threshold.

[0113] As shown in Figure 4, in the synchronization method according to the embodiment of the present disclosure, the first terminal can switch among a desynchronization state, a first synchronization state, and a second synchronization state. Here, the first terminal enters the desynchronization state after being powered on and started up. The switching process among the three states is as follows:

[0114] The first terminal in the desynchronization state synchronizes with the terminal transmitting the second synchronization signaling carried by the PSBCH and switches to the first synchronization state; The first terminal in the desynchronized state synchronizes with the GNSS signal and switches to the second synchronized state; If the first terminal in the first synchronization state times out, it switches to a desynchronization state; The first terminal in the first synchronization state synchronizes with the terminal transmitting the first synchronization signaling carried by the PSSCH or synchronizes with the GNSS signal, and switches to the second synchronization state; a first terminal in the first synchronization state synchronizes with a terminal transmitting a second synchronization signaling carried by the PSBCH and maintains the first synchronization state; The first terminal in the second synchronization state synchronizes with the terminal transmitting the second synchronization signaling carried by the PSBCH and switches to the first synchronization state; The first terminal in the second synchronization state synchronizes with the terminal transmitting the first synchronization signaling carried by the PSSCH or synchronizes with the GNSS signal, and maintains the second synchronization state; The first terminal in the second synchronization state switches to a desynchronization state if the synchronization times out.

[0115] Here, if "synchronization timed out," the synchronization operation was not performed.

[0116] According to the synchronization method of the embodiment of the present disclosure, the first terminal performs a synchronization operation based on the second synchronization signaling carried by the PSBCH to enter the first synchronization state, and then performs a synchronization operation based on the first synchronization signaling carried by the PSSCH to enter the second synchronization state. In this way, the problem of difficulty in synchronization cooperation between vehicular Internet terminals in the distributed architecture of vehicular Internet can be solved, and the correlation standard requirements can be met, having wide applicability. The synchronization state can be divided into the first synchronization state and the second synchronization state to meet the different needs for synchronization accuracy of different systems and improve synchronization accuracy.

[0117] The synchronization process of the synchronization method according to the embodiment of the present disclosure will be described below using a specific example.

[0118] First, we explain the system parameter configuration of the vehicle Internet equipment, such as the RSU and OBU. The system bandwidth is 20 MHz, the duplex method supports half duplex, the subcarrier spacing is 15 kHz, and the cyclic prefix (CP) length is 4.687 μs (5.208 μs (symbol 0)).

[0119] 5 is a schematic diagram of a first scene to which a synchronization method according to an embodiment of the present disclosure is applied. Specifically, the first scene includes four RSUs and one OBU, where only RSU1 can receive GNSS signals.

[0120] The initial states of the four RSUs and one OBU are all in the desynchronized state, and after powering on and starting up, they first search for GNSS signals and do not send synchronization messages.

[0121] When RSU1 receives a GNSS signal, it enters the second synchronization state, and the synchronization level is 1. RSU1 transmits synchronization signaling via PSBCH and PSSCH, respectively, and the inCoverage indicator in the second synchronization signaling carried by PSBCH is 1, the SLSS ID is 0, and the synchronization level in the first synchronization signaling carried by PSSCH is 1.0.

[0122] RSU2 first receives the second synchronization signaling carried by the PSBCH transmitted from RSU1 and enters a first synchronization state, with a synchronization level of 2. RSU2 transmits the second synchronization signaling over the PSBCH, with an inCoverage indicator of 0 and an SLSS ID of 0 in the second synchronization signaling carried by the PSBCH transmitted from RSU2. RSU2 receives the first synchronization signaling transmitted by RSU1 over the PSSCH and enters a second synchronization state, with RSU2 transmitting synchronization signaling over the PSBCH and PSSCH, respectively, with a synchronization level of 1 in the second synchronization signaling carried by the PSBCH, an inCoverage indicator of 1, an SLSS ID of 0, and a synchronization level of 1.1 in the first synchronization signaling carried by the PSSCH.

[0123] RSU3 first receives the second synchronization signaling carried by the PSBCH transmitted from RSU2 and enters a first synchronization state, with a synchronization level of 2. RSU3 transmits the second synchronization signaling via the PSBCH, with an inCoverage indicator of 0 and an SLSS ID of 0 in the second synchronization signaling carried by the PSBCH transmitted from RSU3. RSU3 receives the first synchronization signaling transmitted by RSU2 via the PSSCH and enters a second synchronization state. RSU3 transmits synchronization signaling via the PSBCH and PSSCH, with a synchronization level of 1 in the second synchronization signaling carried by the PSBCH, an inCoverage indicator of 1, an SLSS ID of 0, and a synchronization level of 1.2 in the first synchronization signaling carried by the PSSCH.

[0124] RSU4 first receives the second synchronization signaling carried by the PSBCH transmitted from RSU3, enters a first synchronization state, and has a synchronization level of 2. RSU4 transmits the second synchronization signaling via the PSBCH, and the inCoverage indicator and SLSS ID in the second synchronization signaling carried by the PSBCH are 0 and 0, respectively. RSU4 receives the first synchronization signaling transmitted by RSU3 via the PSSCH, and enters a second synchronization state. RSU4 transmits synchronization signaling via the PSBCH and PSSCH, and the synchronization level in the second synchronization signaling carried by the PSBCH is 1, the inCoverage indicator is 1, the SLSS ID is 0, and the synchronization level in the first synchronization signaling carried by the PSSCH is 1.3.

[0125] OBU1 first receives the secondary synchronization signaling carried by the PSBCH transmitted from RSU3 and enters the first synchronization state, with a synchronization level of 2. OBU1 transmits the secondary synchronization signaling via the PSBCH, where the inCoverage indicator and the SLSS ID in the secondary synchronization signaling carried by the PSBCH transmitted from OBU1 are 0. OBU1 receives the primary synchronization signaling transmitted by RSU3 via the PSSCH and enters the second synchronization state. OBU1 transmits the secondary synchronization signaling via the PSBCH, where the inCoverage indicator and the SLSS ID in the secondary synchronization signaling carried by the PSBCH transmitted from OBU1 are 0.

[0126] 6 is a schematic diagram of a second scenario in which the synchronization method according to the embodiment of the present disclosure is applied. Specifically, the second scenario includes four RSUs and one moving OBU, where only RSU1 to RSU4 have completed synchronization and transmit the second synchronization signaling carried by the PSBCH and the first synchronization signaling carried by the PSSCH.

[0127] At time t1, OBU1 receives the second synchronization signaling carried by the PSBCH transmitted from RSU1 and enters the first synchronization state, without transmitting any synchronization signaling. OBU1 receives the first synchronization signaling transmitted by RSU2 via the PSSCH and enters the second synchronization state. At time t2, OBU1 has already entered the synchronization state. In this case, OBU1 can receive the first synchronization signaling transmitted by RSU2 via the PSSCH and maintain the second synchronization state. At time t3, OBU1 receives the second synchronization signaling transmitted by RSU3 via the PSSCH and maintain the second synchronization state.

[0128] 7, the embodiment of the present disclosure further provides a synchronization device applied to a first terminal, the synchronization device including: a first receiving module 701 and a first synchronization module 702;

[0129] The first receiving module 701 is configured to receive a first synchronization signaling sent by at least one second terminal when said first terminal is in a first synchronization state.

[0130] The first synchronization module 702 is configured to, based on the first synchronization signaling, the first terminal perform a synchronization operation, and the first terminal switch to a second synchronization state.

[0131] According to the synchronization device of the embodiment of the present disclosure, first, the first receiving module 701 receives a first synchronization signaling sent by at least one second terminal when the first terminal is in a first synchronization state; then, the first synchronization module 702 causes the first terminal to perform a synchronization operation based on the first synchronization signaling, and the first terminal switches to a second synchronization state; in this way, the synchronization operation of the first terminal based on the received first synchronization signaling enables the first terminal to switch from the first synchronization state to the second synchronization state, thereby realizing time synchronization between vehicular Internets in an area not covered by satellite signals, and not only solving the problem of difficulty in synchronous cooperation between vehicular Internet terminals in a distributed vehicular Internet architecture, but also improving the synchronization accuracy of the terminals.

[0132] Optionally, the first receiving module 701 is specifically configured to receive the first synchronization signaling carried by a physical sidelink shared channel PSSCH.

[0133] Optionally, the first receiving module 701 is further configured to receive first indication information carried by a physical sidelink control channel PSCCH, wherein the first indication information is used to indicate whether the PSSCH carries the first synchronization signaling.

[0134] Optionally, the first synchronization module 702 is specifically configured to: when the received power of at least one PSSCH carrying the first synchronization signaling is greater than or equal to a first threshold, the first terminal performs a synchronization operation, and the first terminal switches to the second synchronization state.

[0135] Optionally, the device further comprises: and a second synchronization module configured to receive, when the first terminal is in a desynchronization state, second synchronization signaling carried by a physical sidelink broadcast channel (PSBCH) transmitted by at least one third terminal, and to switch the first terminal to the first synchronization state or maintain the desynchronization state.

[0136] Optionally, the device further comprises: and a first determination module configured to determine a first portion of a synchronization level of the first terminal as a first numerical value when the first terminal is in the second synchronization state.

[0137] Optionally, the device further comprises: If a synchronization source of the first terminal is a GNSS signal, determining a second portion of the synchronization level of the first terminal as a second numerical value; and / or a second determination module configured to determine the second part of the synchronization level of the first terminal as n+1 when the value of the second part of the synchronization level attached to the first synchronization signaling transmitted by a synchronization source of the first terminal is n; Here, n≧0 and n is an integer.

[0138] Optionally, the device further comprises: receiving first synchronization signaling carried by at least one PSSCH when the first terminal is in the second synchronization state; a third synchronization module configured to: configure the first terminal to perform a synchronization operation based on the first synchronization signaling carried by the PSSCH; and a second receiving module configured to perform the synchronization operation; Here, the received power of at least one of the PSSCHs is equal to or greater than a second threshold.

[0139] Optionally, the first synchronization signaling comprises: a first part of the synchronization level; a second part of the synchronization level; a sidelink radio frame number; a sidelink subframe number; and Universally Coordinated Time (UTC) and a first timing offset value, which is a timing offset of the terminal transmitting the first synchronization signaling relative to a reference time; an identifier ID of a terminal transmitting the first synchronization signaling; a first timing adjustment value that is an adjustment amount of a synchronization period between a terminal transmitting the first synchronization signaling and its synchronization source; The first synchronization signaling signaling includes at least one of a second timing offset value, which is a timing offset between the terminal transmitting the first synchronization signaling and another terminal, and a terminal ID corresponding to the second timing offset value.

[0140] Optionally, the first synchronization module and the third synchronization module each include: determining, based on the received primary synchronization signaling, a third timing offset value of the first terminal relative to the terminal transmitting the primary synchronization signaling; determining a second timing adjustment value of the first terminal when receiving the first synchronization signaling; determining an actual timing deviation between the first terminal and a terminal transmitting a first synchronization signaling based on the second timing offset value, the first timing adjustment value, the second timing adjustment value, and the third timing offset value; Based on the actual timing deviation, the first terminal is configured to perform a synchronization operation.

[0141] Optionally, when the first synchronization module and the third synchronization module respectively determine an actual timing deviation between the first terminal and a terminal transmitting the first synchronization signaling based on the second timing offset value, the first timing adjustment value, the second timing adjustment value, and the third timing offset value, specifically: The method is configured to calculate an actual timing deviation between the first terminal and a terminal transmitting a first synchronization signaling according to the following equation (1):

number

[0142] Optionally, the first synchronization module and the third synchronization module each specifically: determining, based on the received primary synchronization signaling, a third timing offset value of the first terminal relative to the terminal transmitting the primary synchronization signaling; obtaining the first timing offset value and the first timing adjustment value in the first synchronization signaling; determining an offset value of the first terminal relative to a reference time based on the third timing offset value, the first timing offset value, and the first timing adjustment value; The first terminal is configured to perform a synchronization operation based on an offset value of the first terminal relative to a reference time.

[0143] Optionally, the device further comprises: a fourth synchronization module configured to, when the first terminal is in the second synchronization state, perform a synchronization operation when a first condition is satisfied, and switch the first terminal to the first synchronization state; Here, the first condition is: No GNSS signal has been received within the first period of time; and not receiving a first synchronization signaling carried by the PSSCH within a second time period; receiving second synchronization signaling carried by at least one PSBCH within a third time period, and the received power of the at least one PSBCH being greater than or equal to a third threshold;

[0144] Optionally, the device further comprises: When the first terminal is in a first synchronization state or a second synchronization state, if the first terminal does not receive a GNSS signal within a fourth time, does not receive a first synchronization signaling carried by a PSSCH within a fifth time, and does not receive a second synchronization signaling carried by a PSBCH within a sixth time, the first terminal includes a switching module configured to switch to a desynchronization state.

[0145] Optionally, the device further comprises: When the first terminal is in a desynchronization state or the first synchronization state, upon receiving a GNSS signal, the first terminal synchronizes with the GNSS signal and switches to the second synchronization state; Alternatively, when the first terminal is in the second synchronization state, upon receiving a GNSS signal, the first terminal synchronizes with the GNSS signal.

[0146] It should be understood that the division of the above modules is merely a division of logical functions, and that in actual implementation, all or some of them may be integrated into a physical entity or physically separated. These modules may all be implemented by a processing element calling software, or all may be implemented in hardware. Furthermore, some modules may be implemented by a processing element calling software, while others may be implemented in hardware. For example, the first receiving module may be a separate processing element, or may be integrated into one of the chips of the device. Alternatively, it may be stored in the memory of the device in the form of program code and executed by one of the processing elements calling the function of the determining module. Other modules are implemented in a similar manner. Furthermore, all or some of these modules may be integrated or implemented independently. The processing element described herein may be an integrated circuit capable of processing signals. In the implementation process, each step of the above method or each of the above modules may be completed by a hardware integrated logic circuit in a processor element or by instructions in software form.

[0147] For example, each module, unit, sub-unit, or sub-module may be one or more integrated circuits configured to implement the above method, such as one or more application specific integrated circuits (ASICs), one or more microprocessors (DSPs), or one or more field programmable gate arrays (FPGAs). Furthermore, when a certain module is implemented in the form of program code scheduling by a processing element, the processing element may be a general-purpose processor, such as a central processing unit (CPU) or other processor capable of calling program code. Furthermore, these modules may be integrated to be implemented as a system-on-a-chip (SOC).

[0148] The terms "first," "second," and the like, used in the specification and claims of this disclosure, are intended to distinguish between similar objects without necessarily being used to describe a particular order or priority. It should be understood that terms used in this manner are interchangeable where appropriate to allow the implementation of the embodiments of the disclosure described herein, for example, in an order other than that illustrated or described herein. Furthermore, the terms "comprise" and "have," and any variations thereof, are intended to cover non-exclusive "comprises," e.g., a process, method, system, product, or apparatus comprising a series of steps or units need not be limited to the explicitly listed steps or units, but may include other steps or units not explicitly listed, or other steps or units inherent in the process, method, product, or apparatus. Furthermore, in the specification and claims, the use of "and / or" refers to at least one of the connected objects, e.g., A and / or B and / or C refers to a single A, a single B, a single C, and the seven cases where both A and B are present, both B and C are present, both A and C are present, and A, B, and C are present. Similarly, "at least one of A and B" as used in this specification and claims should be understood to mean "there is a single A, a single B, or both A and B."

[0149] As shown in FIG. 8 , an embodiment of the present disclosure further provides a terminal, wherein the terminal is a first terminal, and includes a transceiver 810, a memory 820, a processor 800, and a computer program stored on the memory 820 and executable by the processor 800, wherein the transceiver 810 is connected to the processor 800 and the memory 820 via a bus interface, and wherein the processor 800 reads the program in the memory 820 and performs the following: receiving a first synchronization signaling transmitted by at least one second terminal when the first terminal is in a first synchronization state; Based on the first synchronization signaling, the first terminal performs a synchronization operation, and the first terminal is used to switch to a second synchronization state.

[0150] Note that in FIG. 8, the bus architecture can include any number of interconnected buses and bridges, specifically connecting various circuits, such as one or more processors, represented by processor 800, and memory, represented by memory 820. The bus architecture can also connect various other circuits, such as peripherals, regulators, and power management circuits, which are well known in the art and therefore will not be described further herein. The bus interface provides an interface. The transceiver 810 may be multiple elements, including a transmitter and a transceiver, providing a unit for communicating with various other devices over a transmission medium. For different user devices, the user interface 830 may be an interface that can be externalized or internalized to the required device, and the connected devices may include, but are not limited to, a keypad, a display, a speaker, a microphone, a joystick, etc. The processor 800 is responsible for managing the bus architecture and general processing, while the memory 820 can store data used by the processor 800 when performing operations.

[0151] According to the terminal of the embodiment of the present disclosure, the processor 800 reads the program in the memory 820 and executes the process of receiving a first synchronization signaling sent by at least one second terminal when the first terminal is in a first synchronization state, and based on the first synchronization signaling, the first terminal performs a synchronization operation and switches to a second synchronization state. In this way, the synchronization operation of the first terminal based on the received first synchronization signaling enables the first terminal to switch from the first synchronization state to the second synchronization state, thereby realizing time synchronization between vehicular Internets in the range where satellite signals are not covered, and not only solving the problem of difficulty in synchronous cooperation between vehicular Internet terminals in the distributed architecture of vehicular Internet, but also improving the synchronization accuracy of the terminals.

[0152] It should be noted that the terminals of the embodiments of the present disclosure can implement the processes of the above-described synchronization method embodiments to achieve the same technical effects, and the description thereof will be omitted here to avoid redundancy.

[0153] As will be understood by those skilled in the art, the realization of all or part of the steps in the above embodiments can be completed by hardware, or can be completed by instructing relevant hardware by a computer program, the computer program including instructions for performing some or all of the steps of the above method, the computer program can be stored in a readable storage medium, and the storage medium may be any type of storage medium.

[0154] In addition, the embodiments of the present disclosure further provide a computer-readable storage medium storing a program, which, when executed by a processor, can realize the processes of the above-mentioned synchronization method embodiments to achieve the same technical effects, and to avoid redundancy, the description will be omitted here. Here, the computer-readable storage medium may be a read-only memory (ROM), a random access memory (RAM), a magnetic disk, an optical disk, etc.

[0155] It is clear that the components or steps of the apparatus and method of the present disclosure can be disassembled and / or recombined. Such disassembly and / or recombination should be considered equivalent methods of the present disclosure. Furthermore, the steps of performing the above-described series of processes may be naturally performed in the order described or in chronological order, but are not necessarily performed in chronological order, and some steps can be performed in parallel or independently of each other. Those skilled in the art will recognize that all or any of the steps or components of the method and apparatus of the present disclosure can be implemented in hardware, firmware, software, or a combination thereof on any computing device (including a processor, a storage medium, etc.) or network of computing devices, and this implementation can be achieved by those skilled in the art by utilizing basic programming skills after reading the description of the present disclosure.

[0156] Therefore, the objectives of the present disclosure can also be achieved by executing a program or group of programs on any computing device. The computing device may be a known general-purpose means. Therefore, the objectives of the present disclosure can also be achieved by simply providing a program product including program code that realizes the above-described method or device. In other words, such a program product also constitutes the present disclosure, and a storage medium storing such a program product also constitutes the present disclosure. Obviously, this storage medium may be any known storage medium or any storage medium developed in the future.

[0157] It should be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and need not require or imply the existence of any such actual relationship or order between those entities or operations. Furthermore, the terms "comprise" and "have," or any other variations thereof, are intended to cover a non-exclusive "comprise," whereby, when including a process, method, article, or device of a series of elements, it not only includes those elements but also other elements not expressly listed or elements inherent in such process, method, article, or device. Absent further limitations, an element defined by the phrase "comprises" does not exclude the presence of other identical elements in a process, method, article, or device that includes the element.

[0158] The above is a preferred embodiment of the present disclosure. However, those skilled in the art may make some improvements and modifications without departing from the above principles of the present disclosure, and these improvements and modifications should also be considered as within the scope of protection of the present disclosure.

Claims

1. A synchronization method applied to a first terminal, comprising: The method comprises: receiving a first synchronization signaling transmitted by at least one second terminal when the first terminal is in a first synchronization state; Based on the first synchronization signaling, the first terminal performs a synchronization operation, and the first terminal switches to a second synchronization state; Receiving first synchronization signaling transmitted by at least one second terminal includes: receiving the first synchronization signaling carried by a physical sidelink shared channel (PSSCH); The first synchronization signaling comprises: a first part of a synchronization level; a second part of the synchronization level; a sidelink radio frame number; a first timing offset value, which is a timing offset of the terminal transmitting the first synchronization signaling relative to a reference time; an identifier ID of a terminal transmitting the first synchronization signaling; a first timing adjustment value that is an adjustment amount of a synchronization period between a terminal transmitting the first synchronization signaling and its synchronization source; A synchronization method comprising: a second timing offset value, which is a timing offset between a terminal transmitting a first synchronization signaling and another terminal; and a terminal ID corresponding to the second timing offset value.

2. The method further comprises: receiving first indication information carried by a physical sidelink control channel (PSCCH); The first indication information is used to indicate whether the PSSCH carries the first synchronization signaling. The method of claim 1.

3. The first terminal performs a synchronization operation based on the first synchronization signaling, and the first terminal switches to a second synchronization state. If the received power of at least one PSSCH carrying the first synchronization signaling is equal to or greater than a first threshold, the first terminal performs a synchronization operation, and the first terminal switches to the second synchronization state. The method of claim 1.

4. The method further comprises: When the first terminal is in a desynchronization state, the first terminal receives second synchronization signaling carried by a physical sidelink broadcast channel (PSBCH) transmitted by at least one third terminal, and switches to the first synchronization state or maintains the desynchronization state. The method of claim 1.

5. The method further comprises: determining a first portion of a synchronization level of the first terminal as a first numerical value when the first terminal is in the second synchronization state; The method of claim 1.

6. The method further comprises: If the synchronization source of the first terminal is a GNSS signal, determining a second portion of the synchronization level of the first terminal as a second numerical value; and / or When the value of the second part of the synchronization level attached to the first synchronization signaling transmitted by the synchronization source of the first terminal is n, determining the second part of the synchronization level of the first terminal as n+1; where n≧0 and n is an integer. The method of claim 5.

7. The method further comprises: receiving first synchronization signaling carried by at least one PSSCH when the first terminal is in the second synchronization state; The first terminal performs a synchronization operation based on first synchronization signaling carried by the PSSCH; Here, the received power of at least one of the PSSCHs is equal to or greater than a second threshold. The method of claim 1.

8. The first synchronization signaling further comprises: a sidelink subframe number; and Universally Coordinated Time (UTC) and Contains at least one of The method of claim 1.

9. The first terminal performing a synchronization operation includes: determining, based on the received primary synchronization signaling, a third timing offset value of the first terminal relative to the terminal transmitting the primary synchronization signaling; determining a second timing adjustment value of the first terminal when receiving the first synchronization signaling; determining an actual timing deviation between the first terminal and a terminal transmitting a first synchronization signaling based on the second timing offset value, the first timing adjustment value, the second timing adjustment value, and the third timing offset value; and performing a synchronization operation at the first terminal based on the actual timing deviation. The method of claim 8.

10. determining an actual timing deviation between the first terminal and a terminal transmitting first synchronization signaling based on the second timing offset value, the first timing adjustment value, the second timing adjustment value, and the third timing offset value; Calculating an actual timing deviation between the first terminal and a terminal transmitting a first synchronization signaling according to the following equation (1): [Equation 1] where x is the first terminal, y is the terminal transmitting the first synchronization signaling, and Rt ｘｙ is the actual timing deviation between the first terminal and the terminal transmitting the first synchronization signaling, and Ta ｙｘ is the second timing offset value, and Ta ｘｙ is the third timing offset value, Td ｘ is the second timing adjustment value, and Td ｙ is the first timing adjustment value, and Δt ｙｘ is the timing measurement error of the terminal transmitting the primary synchronization signaling, and Δt ｘｙ is the timing measurement error of the first terminal 10. The method of claim 9.

11. The first terminal performing a synchronization operation includes: determining, based on the received primary synchronization signaling, a third timing offset value of the first terminal relative to the terminal transmitting the primary synchronization signaling; obtaining the first timing offset value and the first timing adjustment value in the first synchronization signaling; determining an offset value of the first terminal relative to a reference time based on the third timing offset value, the first timing offset value, and the first timing adjustment value; and performing a synchronization operation by the first terminal based on the offset value of the first terminal relative to a reference time. The method of claim 8.

12. The method further comprises: When the first terminal is in the second synchronization state, if a first condition is satisfied, the first terminal performs a synchronization operation, and the first terminal switches to the first synchronization state; Here, the first condition is: No GNSS signal is received within a first time period; and not receiving a first synchronization signaling carried by the PSSCH within a second time period; receiving second synchronization signaling carried by at least one PSBCH within a third time period, and a received power of the at least one PSBCH being equal to or greater than a third threshold. The method of claim 1.

13. The method further comprises: When the first terminal is in the first synchronization state or the second synchronization state, if the first terminal does not receive a GNSS signal within a fourth time, does not receive first synchronization signaling carried by a PSSCH within a fifth time, and does not receive second synchronization signaling carried by a PSBCH within a sixth time, the first terminal switches to a desynchronization state. The method of claim 1.

14. The method further comprises: When the first terminal is in a desynchronization state or the first synchronization state, upon receiving a GNSS signal, the first terminal synchronizes with the GNSS signal and switches to the second synchronization state; Alternatively, when the first terminal is in the second synchronization state, upon receiving a GNSS signal, the first terminal synchronizes with the GNSS signal. The method of claim 1.

15. A terminal, the terminal is a first terminal, a transceiver, a memory, a processor, and a computer program stored in the memory and executable by the processor; A terminal which, when said processor executes said computer program, implements the synchronization method according to any one of claims 1 to 14.

16. A synchronization device applied to a first terminal, The synchronization device a first receiving module configured to receive first synchronization signaling transmitted by at least one second terminal when the first terminal is in a first synchronization state; a first synchronization module configured to, based on the first synchronization signaling, perform a synchronization operation, and switch the first terminal to a second synchronization state; The first receiving module receiving first synchronization signaling transmitted by at least one second terminal includes: receiving the first synchronization signaling carried by a physical sidelink shared channel (PSSCH); The first synchronization signaling comprises: a first part of a synchronization level; a second part of the synchronization level; a sidelink radio frame number; a first timing offset value, which is a timing offset of the terminal transmitting the first synchronization signaling relative to a reference time; an identifier ID of a terminal transmitting the first synchronization signaling; a first timing adjustment value that is an adjustment amount of a synchronization period between a terminal transmitting the first synchronization signaling and its synchronization source; A synchronization device comprising: a second timing offset value that is a timing offset between a terminal transmitting first synchronization signaling and another terminal; and a terminal ID corresponding to the second timing offset value.

17. A computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the synchronization method of any one of claims 1 to 14.

Images