A synchronization method, device and terminal

Abstract

The present invention provides a synchronization method, device and terminal. The method is applied to a first terminal, comprising: sending a pilot signal and a first synchronization signaling; wherein the first synchronization signaling is used to indicate at least one of the following synchronization data: the synchronization level of the first terminal; the wireless frame and subframe number corresponding to the first synchronization signaling; the identity ID of the first terminal; the first timing offset value of the synchronization source, the first timing offset value is the timing offset of the synchronization source of the first terminal relative to the reference time; the first timing adjustment value, the first timing adjustment value is the adjustment amount when the first terminal synchronizes with the synchronization source; the second timing offset value of the first terminal, the second timing offset value is the timing offset between the first terminal and the second terminal; the difference between the first timing offset value and the timing adjustment value; the difference between the second timing offset value and the timing adjustment value. The solution of the present invention can achieve accurate synchronization between vehicle networking terminals.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a synchronization method, device and terminal. Background Art

[0002] The location information of vehicles and related positioning technologies are the core of IoV technology, which is not only related to the safety of vehicles during driving, but also affects the safety of other traffic participants and the development of various IoV applications. At present, the positioning method of IoV mainly relies on the Global Navigation Satellite System (GNSS). However, when the vehicle is in a complex environment such as an urban canyon, overpass, viaduct, underground parking lot, tunnel, etc., it may not be able to receive satellite signals and cannot perform time synchronization through satellite signals.

[0003] However, the internal clock accuracy of the Internet of Vehicles equipment is low and cannot meet the requirements of high-precision time synchronization for a long time. In the existing technology, there is no solution for direct link synchronization signals that meets industry standards and can be implemented. At the same time, under the distributed architecture of the Internet of Vehicles, synchronization and coordination between Internet of Vehicles terminals is difficult. Summary of the invention

[0004] The present invention provides a synchronization method, device and terminal, which solve the problem of difficulty in synchronization and coordination between Internet of Vehicles terminals under the distributed architecture of the Internet of Vehicles.

[0005] In a first aspect, an embodiment of the present invention provides a synchronization method, applied to a first terminal, the method comprising:

[0006] Sending a pilot signal and a first synchronization signaling; wherein the first synchronization signaling is used to indicate at least one of the following synchronization data:

[0007] a synchronization level of the first terminal;

[0008] The radio frame and subframe number corresponding to the first synchronization signaling;

[0009] The identity ID of the first terminal;

[0010] a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling;

[0011] a first timing adjustment value, where the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling;

[0012] a second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal;

[0013] a difference between the first timing offset value and the first timing adjustment value;

[0014] The difference between the second timing offset value and the first timing adjustment value.

[0015] In a second aspect, an embodiment of the present invention provides a synchronization method, applied to a second terminal, the method comprising:

[0016] Receiving a pilot signal and a first synchronization signaling sent by a first terminal;

[0017] When the synchronization level of the first terminal is higher than the synchronization level of the second terminal, synchronizing with the first terminal according to the first synchronization signaling;

[0018] The first synchronization signaling is used to indicate at least one of the following synchronization data:

[0019] a synchronization level of the first terminal;

[0020] The radio frame and subframe number corresponding to the first synchronization signaling;

[0021] The identity ID of the first terminal;

[0022] a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling;

[0023] a first timing adjustment value, where the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling;

[0024] a second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal;

[0025] a difference between the first timing offset value and the first timing adjustment value;

[0026] The difference between the second timing offset value and the first timing adjustment value.

[0027] In a third aspect, an embodiment of the present invention provides a synchronization method, applied to a third terminal, the method comprising:

[0028] Receiving a pilot signal and a first synchronization signaling sent by at least one first terminal;

[0029] synchronizing with the first terminal with the highest synchronization level according to the first synchronization signaling sent by the first terminal with the highest synchronization level;

[0030] The first synchronization signaling is used to indicate at least one of the following synchronization data:

[0031] a synchronization level of the first terminal;

[0032] The radio frame and subframe number corresponding to the first synchronization signaling;

[0033] The identity ID of the first terminal;

[0034] a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling;

[0035] a first timing adjustment value, where the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling;

[0036] a second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal;

[0037] a difference between the first timing offset value and the first timing adjustment value;

[0038] The difference between the second timing offset value and the first timing adjustment value.

[0039] In a fourth aspect, an embodiment of the present invention provides a synchronization device, applied to a first terminal, including:

[0040] The first sending module is configured to send a pilot signal and a first synchronization signaling; wherein the first synchronization signaling is used to indicate at least one of the following synchronization data:

[0041] a synchronization level of the first terminal;

[0042] The radio frame and subframe number corresponding to the first synchronization signaling;

[0043] The identity ID of the first terminal;

[0044] a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling;

[0045] a first timing adjustment value, where the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling;

[0046] a second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal;

[0047] a difference between the first timing offset value and the first timing adjustment value;

[0048] The difference between the second timing offset value and the first timing adjustment value.

[0049] In a fifth aspect, an embodiment of the present invention provides a synchronization device, applied to a second terminal, including:

[0050] A first receiving module, configured to receive a pilot signal and a first synchronization signaling sent by a first terminal;

[0051] A first synchronization processing module, configured to synchronize with the first terminal according to the first synchronization signaling when the synchronization level of the first terminal is higher than the synchronization level of the second terminal;

[0052] The first synchronization signaling is used to indicate at least one of the following synchronization data:

[0053] a synchronization level of the first terminal;

[0054] The radio frame and subframe number corresponding to the first synchronization signaling;

[0055] The identity ID of the first terminal;

[0056] a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling;

[0057] a first timing adjustment value, where the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling;

[0058] a second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal;

[0059] a difference between the first timing offset value and the first timing adjustment value;

[0060] The difference between the second timing offset value and the first timing adjustment value.

[0061] In a sixth aspect, an embodiment of the present invention provides a synchronization device, applied to a third terminal, including:

[0062] A third receiving module, configured to receive a pilot signal and a first synchronization signaling sent by at least one first terminal;

[0063] A second synchronization processing module, configured to synchronize with the first terminal with the highest synchronization level according to the first synchronization signaling sent by the first terminal with the highest synchronization level;

[0064] The first synchronization signaling is used to indicate at least one of the following synchronization data:

[0065] a synchronization level of the first terminal;

[0066] The radio frame and subframe number corresponding to the first synchronization signaling;

[0067] The identity ID of the first terminal;

[0068] a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling;

[0069] a first timing adjustment value, where the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling;

[0070] a second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal;

[0071] a difference between the first timing offset value and the first timing adjustment value;

[0072] The difference between the second timing offset value and the first timing adjustment value.

[0073] In a seventh aspect, an embodiment of the present invention provides a terminal, which is a first terminal, comprising: a transceiver, a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the steps of the synchronization method described in the first aspect.

[0074] In an eighth aspect, an embodiment of the present invention provides a terminal, which is a second terminal, comprising: a transceiver, a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the steps of the synchronization method described in the second aspect.

[0075] In the ninth aspect, an embodiment of the present invention provides a terminal, which is a third terminal, comprising: a transceiver, a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the steps of the synchronization method described in the third aspect.

[0076] In a tenth aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the synchronization method as described in the first aspect, the second aspect, or the third aspect.

[0077] The beneficial effects of the above technical solution of the present invention are:

[0078] In the above scheme, a pilot signal and a first synchronization signaling are sent by the first terminal; wherein the first synchronization signaling is used to indicate at least one of the following synchronization data: a synchronization level of the first terminal; a wireless frame and subframe number corresponding to the first synchronization signaling; an identity ID of the first terminal; a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of the synchronization source of the first terminal relative to a reference time when the first synchronization signaling is sent; a first timing adjustment value, wherein the first timing adjustment value is an adjustment amount when the first terminal synchronizes with the synchronization source when the first synchronization signaling is sent; a second timing offset value of the first terminal, wherein the second timing offset value is a timing offset between the first terminal and the second terminal; a difference between the first timing offset value and the first timing adjustment value; a difference between the second timing offset value and the first timing adjustment value. Other Internet of Vehicles terminals achieve synchronization by receiving the pilot signal and the first synchronization signaling sent by the first terminal, which can solve the problem of difficulty in synchronization coordination between Internet of Vehicles terminals under the distributed architecture of the Internet of Vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Figure 1 One of the flowcharts showing the synchronization method according to an embodiment of the present invention;

[0080] Figure 2 A schematic diagram showing that the timing adjustment according to an embodiment of the present invention is performed within a gap in which synchronization signaling is sent;

[0081] Figure 3 A second flowchart showing the synchronization method according to an embodiment of the present invention;

[0082] Figure 4 A schematic diagram showing the sending of synchronization signaling according to an embodiment of the present invention;

[0083] Figure 5 A schematic diagram showing a synchronization process according to an embodiment of the present invention;

[0084] Figure 6 A second schematic diagram showing a synchronization process according to an embodiment of the present invention;

[0085] Figure 7 A schematic diagram showing one of the application scenarios of an embodiment of the present invention;

[0086] Figure 8 A second schematic diagram showing an application scenario of an embodiment of the present invention;

[0087] Fig. 9 A third flowchart showing a synchronization method according to an embodiment of the present invention;

[0088] Fig.10 A third schematic diagram showing an application scenario of an embodiment of the present invention;

[0089] Fig.11 One of the structural block diagrams of the synchronization device according to the embodiment of the present invention;

[0090] Fig.12 A second structural block diagram showing a synchronization device according to an embodiment of the present invention;

[0091] Fig.13 A third structural block diagram showing a synchronization device according to an embodiment of the present invention;

[0092] Fig.14 One of the schematic diagrams showing the hardware structure of the terminal of the present invention;

[0093] Fig.15 One of the schematic diagrams showing the hardware structure of the terminal of the present invention;

[0094] Fig.16 One of the schematic diagrams showing the hardware structure of the terminal of the present invention. DETAILED DESCRIPTION

[0095] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail in conjunction with the accompanying drawings and specific embodiments. In the following description, specific details such as specific configurations and components are provided only to help fully understand the embodiments of the present invention. Therefore, it should be clear 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 invention. In addition, for clarity and brevity, the description of known functions and structures is omitted.

[0096] It should be understood that the references to "one embodiment" or "an embodiment" throughout the specification mean that the specific features, structures, or characteristics associated with the embodiment are included in at least one embodiment of the present invention. Therefore, the references to "in one embodiment" or "in an embodiment" appearing throughout the specification do not necessarily refer to the same embodiment. In addition, these specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0097] In various embodiments of the present invention, it should be understood that the size of the serial numbers of the following processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0098] Additionally, the terms "system" and "network" are often used interchangeably herein.

[0099] In the embodiments provided in the present application, it should be understood that "B corresponding to A" means that B is associated with A, and B can be determined according to A. However, it should also be understood that determining B according to A does not mean determining B only according to A, and B can also be determined according to A and / or other information.

[0100] In the embodiment of the present invention, the form of the access network is not limited, and may be an access network including a macro base station (Macro Base Station), a micro base station (Pico Base Station), a Node B (the name of a 3G mobile base station), an enhanced base station (eNB), a home enhanced base station (Femto eNB or Home eNode B or Home eNB or HeNB), a relay station, an access point, an RRU (Remote Radio Unit), an RRH (Remote Radio Head), etc. The user terminal may be a mobile phone (or mobile phone), or other equipment capable of sending or receiving wireless signals, including user equipment, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a CPE (Customer Premise Equipment) capable of converting a mobile signal into a WiFi signal, or a mobile smart hotspot, a smart home appliance, or other equipment that can spontaneously communicate with a mobile communication network without human operation.

[0101] Specifically, the embodiments of the present invention provide a synchronization method, device and terminal, which solve the problem of difficulty in synchronization and coordination between Internet of Vehicles terminals under the distributed architecture of the Internet of Vehicles in the prior art.

[0102] First embodiment

[0103] like Figure 1 As shown, an embodiment of the present invention provides a synchronization method, which is applied to a first terminal. Optionally, the first terminal is a first road side unit (RSU), and specifically includes the following steps:

[0104] Step 11: Send a pilot signal and a first synchronization signaling; wherein the first synchronization signaling is used to indicate at least one of the following synchronization data:

[0105] a synchronization level of the first terminal;

[0106] The radio frame and subframe number corresponding to the first synchronization signaling;

[0107] The identity ID of the first terminal;

[0108] a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling;

[0109] a first timing adjustment value, where the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling;

[0110] a second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal;

[0111] a difference between the first timing offset value and the first timing adjustment value;

[0112] The difference between the second timing offset value and the first timing adjustment value.

[0113] In this step, sending the pilot signal and the first synchronization signaling includes: sending the first synchronization signaling through a physical sidelink control channel (PSCCH); or sending the first synchronization signaling through the PSCCH and a physical sidelink shared channel (PSSCH).

[0114] The pilot signal is the demodulation reference signal (DMRS). It should be noted that for LTE-V2X and NR-V2X systems, when performing PSCCH transmission, the DMRS signal is sent at the same time, which can be used for PSCCH channel detection on the receiving side; when performing PSSCH transmission, the DMRS signal is sent at the same time, which can be used for PSSCH channel detection on the receiving side.

[0115] It should be noted that, for the timing adjustment, the first timing adjustment value is an adjustment performed by the first terminal in the interval of sending the first synchronization signaling, such as Figure 2 As shown, it is a schematic diagram showing the timing relationship between the sending of the first synchronization signaling and the timing adjustment.

[0116] The radio frame and subframe number corresponding to the first synchronization signaling are used to achieve millisecond-level synchronization.

[0117] In the above embodiment, a pilot signal and a first synchronization signaling are sent by the first terminal; other vehicle network terminals are synchronized by receiving the pilot signal and the first synchronization signaling sent by the first terminal, wherein, when the other vehicle network terminals are RSUs, the RSU receives the pilot signal and the first synchronization signaling sent by the first terminal, and when it is determined that the synchronization level of the first terminal is higher than that of itself, it can be synchronized with the first terminal according to the first timing adjustment value and the second timing offset value; or according to the first timing adjustment value, the second timing offset value and the first timing offset value, while synchronizing with the first terminal, synchronization with the synchronization source is achieved; or according to the difference between the second timing offset value and the first timing adjustment value, synchronization with the first terminal is achieved, or according to the difference between the first timing offset value and the first timing adjustment value and the difference between the second timing offset value and the first timing adjustment value, while synchronizing with the first terminal, synchronization with the synchronization source is achieved, or according to the first timing adjustment value, synchronization with the synchronization source is achieved, or according to the first timing offset value, synchronization with the synchronization source is achieved. When the other Internet of Vehicles terminals are on-board units (OBU), the OBU receives a pilot signal and a first synchronization signaling sent by at least one first terminal; and performs synchronization processing with the first terminal with the highest synchronization level according to the first synchronization signaling sent by the first terminal with the highest synchronization level; therefore, this embodiment can achieve synchronous coordination between Internet of Vehicles terminals even when time synchronization cannot be performed through satellite signals and when the internal clock accuracy of the Internet of Vehicles equipment is low and cannot meet the requirements of high-precision time synchronization for a long time, and can solve the problem of difficult synchronous coordination between Internet of Vehicles terminals under the distributed architecture of the Internet of Vehicles.

[0118] In one embodiment, sending the first synchronization signaling through the PSCCH and the direct link shared channel PSSCH includes:

[0119] Sending a first part of the first synchronization signaling via PSCCH; and

[0120] Sending a second part of the first synchronization signaling via PSSCH;

[0121] The first part is used to indicate whether the PSCCH carries the first synchronization signaling; the PSSCH indicated by the PSCCH carries the second part of the first synchronization signaling, and the second part is used to indicate the synchronization data.

[0122] Specifically, the first part is carried by sidelink control information (Sidelink Control Information, SCI for short).

[0123] In this embodiment, the first synchronization signaling includes two parts, the first part is carried on the PSCCH, and the second part is carried on the PSSCH. Among them, the industry standard YD / T3755-2020 "Technical requirements for roadside equipment supporting direct communication based on LTE network wireless communication technology" stipulates that the direct link control information SCI adopts SCI format 1, and there are currently at least 7 bits left as padding bits. As an implementation method, the first part of the first synchronization signaling in this embodiment can use the last N bits of SCI in PSCCH: a i 、a i+1 ,……,a i+N-1 It is used to carry and indicate the current subframe number and whether it is synchronization signaling. a j is the value of the jth bit; i=31-N+1. If the value of a is greater than 0, it indicates that the PSCCH carries the first part of the first synchronization signaling, and the PSSCH indicated by the PSCCH carries the second part of the message.

[0124] Exemplarily, the format of the second part of the first synchronization signaling sent by the first RSU (first terminal) may be:

[0125]

[0126] The second timing offset is a timing offset measured by the first RSU relative to the local time (the first RSU) through the synchronization signaling sent by the N nearby RSUs monitored.

[0127] In another embodiment, when the first synchronization signaling is sent through the PSCCH, the format of the first synchronization signaling is:

[0128]

[0129] In one embodiment, the synchronization level of the first terminal includes at least one of the following:

[0130] a first synchronization level, wherein the first synchronization level indicates that a synchronization source of the first terminal is a Global Navigation Satellite System (GNSS) signal;

[0131] The n+1th synchronization level, wherein the n+1th synchronization level indicates that the synchronization source of the first terminal is a terminal of the nth synchronization level; wherein n≥1, and n is a positive integer.

[0132] In this embodiment, the terminal device that uses the GNSS signal for synchronization calibration has the highest synchronization level, which can be recorded as 1, and the synchronization level of the vehicle networking terminal device that is synchronized with the signal source with the synchronization level n is one level lower, which is recorded as n + 1. There may be no direct relationship between the synchronization level between the RSUs and the synchronization level in the signal sent in the PSBCH.

[0133] It should be noted that, for the receiving end, only when the synchronization level of the source address of the received synchronization signaling is higher than that of the current device by one level or more, the current device performs synchronization calibration according to the synchronization signaling.

[0134] In one embodiment, the synchronization method further includes:

[0135] Sending a second synchronization signaling on a direct link broadcast channel PSBCH sent through a reserved subframe;

[0136] The second synchronization signaling is used to indicate the synchronization level of the first terminal; the second synchronization signaling includes: indication information of whether the first terminal device is within the coverage of the GNSS and a direct link synchronization signal index.

[0137] In this embodiment, according to the bitmap mapping, the subframes in the subframe number (SFN) period (10240ms) that cannot be divided by the bitmap are called reserved subframes. The number of reserved subframes N reserved The calculation method is as follows:

[0138] N reserved =(10240-N slss -N dssf )modL bitmap

[0139] Among them, L bitmap N is the bitmap length configured by the higher layer. SLSS N is the number of subframes configured as SLSS resources in 10240 subframes. dssf It is the total number of downlink subframes and special subframes in 10240 subframes when direct link transmission occurs in one TDD cellular cell.

[0140] Specifically, the correspondence between the synchronization level, the indication information, and the through link synchronization signal index includes at least one of the following:

[0141] When the indication information is 1 and the through link synchronization signal index is 0, it indicates that the synchronization level of the first terminal device is the first synchronization level;

[0142] When the indication information is 0 and the direct link synchronization signal index is 0, it indicates that the synchronization level of the first terminal device is not the first synchronization level.

[0143] In this embodiment, when the synchronization source of the first terminal is the GNSS synchronization signal, the indication information: the inCoverage flag is 1, indicating that the local device is within the coverage of the GNSS, and the direct link synchronization signal index (SLSS ID) is 0; when the first terminal is synchronized through the synchronization signaling sent by other terminals (such as RSU), the indication information: the inCoverage flag is 0, indicating that the local device is outside the coverage of the GNSS, and the SLSS ID is 0.

[0144] Furthermore, it should be pointed out that each RSU is synchronized with its synchronization source RSU. Due to measurement errors and crystal oscillator errors, there is usually a certain deviation between the synchronization source and the reference time. In the process of keeping consistent with the synchronization source, sometimes there is a misadjustment that deviates from the reference clock, resulting in the accumulation of multi-level synchronization adjustment errors. If the deviation between the RSU and the reference time can be directly obtained, the probability of misadjustment can be effectively reduced, and the accumulation of multi-level synchronization adjustment errors can be reduced. The present invention can achieve timing adjustment of the RSU based on the reference time by having each RSU periodically broadcast the offset relative to the reference time, thereby effectively reducing the probability of misadjustment and reducing the accumulation of multi-level synchronization adjustment errors.

[0145] Second embodiment

[0146] like Figure 7 As shown, the second embodiment of the present invention provides a synchronization method, which is applied to a second terminal. Optionally, the second terminal is a second RSU, and specifically includes the following steps:

[0147] Step 21: receiving a pilot signal and a first synchronization signaling sent by a first terminal;

[0148] The first synchronization signaling is used to indicate at least one of the following synchronization data:

[0149] a synchronization level of the first terminal;

[0150] The radio frame and subframe number corresponding to the first synchronization signaling;

[0151] The identity ID of the first terminal;

[0152] a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling;

[0153] a first timing adjustment value, where the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling;

[0154] a second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal;

[0155] a difference between the first timing offset value and the first timing adjustment value;

[0156] The difference between the second timing offset value and the first timing adjustment value.

[0157] In this step, receiving a pilot signal and a first synchronization signaling sent by a first terminal includes:

[0158] Receiving the first synchronization signaling sent by the first terminal through the direct link control channel PSCCH; or

[0159] The first synchronization signaling is received by the first terminal through the PSCCH and the direct link shared channel PSSCH; wherein the pilot signal is a demodulation reference signal (DeModulation Reference Signal, referred to as DMRS).

[0160] It should be pointed out that for LTE-V2X systems and NR-V2X systems, when PSCCH transmission is performed, DMRS signals are sent at the same time, which can be used for PSCCH channel detection on the receiving side; when PSSCH transmission is performed, DMRS signals are sent at the same time, which can be used for PSSCH channel detection on the receiving side.

[0161] It should be noted that, for the timing adjustment, the first timing adjustment value is an adjustment performed by the first terminal in the interval of sending the first synchronization signaling, such as Figure 2 As shown, it is a schematic diagram showing the timing relationship between the sending of the first synchronization signaling and the timing adjustment.

[0162] It can be understood that if T is the relative offset value between the RSU and the reference time, and Td is the timing adjustment when sending the first synchronization signaling, then when sending the first synchronization signaling, the offset value between the RSU and the reference time is T+Td.

[0163] Step 22: When the synchronization level of the first terminal is higher than the synchronization level of the second terminal, synchronize with the first terminal according to the first synchronization signaling.

[0164] In this step, when the second RSU determines that the synchronization level of the first RSU is higher than its own, it can synchronize with the first terminal according to the first timing adjustment value and the second timing offset value; or synchronize with the synchronization source while synchronizing with the first terminal according to the first timing adjustment value, the second timing offset value and the first timing offset value; or synchronize with the first terminal according to the difference between the second timing offset value and the first timing adjustment value, or synchronize with the synchronization source while synchronizing with the first terminal according to the difference between the first timing offset value and the first timing adjustment value and the difference between the second timing offset value and the first timing adjustment value.

[0165] In the above embodiment, synchronous coordination between RSUs can be achieved even when time synchronization cannot be performed via satellite signals and the internal clock accuracy of the Internet of Vehicles equipment is low and cannot meet the requirements of high-precision time synchronization for a long time.

[0166] It should be pointed out that due to the propagation distance between RSUs, the synchronization signal will produce a propagation delay during the propagation process, resulting in a timing drift between the RSUs and halving the maximum transmission distance of the synchronization signal. In this embodiment, by transmitting the timing offset value and timing adjustment between the first RSU and the second RSU in the first synchronization signaling, the influence of the propagation distance on the timing can be eliminated, which is beneficial to improving the synchronization accuracy between the RSUs.

[0167] In one embodiment, in the above step 22, synchronizing with the first terminal according to the first synchronization signaling includes:

[0168] By receiving the first synchronization signaling sent by the first terminal, the second terminal determines a third timing offset value relative to the first terminal;

[0169] When the second terminal determines to receive the first synchronization signaling, a second timing adjustment value of the second terminal;

[0170] Calculate an actual timing deviation between the second terminal and the first terminal according to the second timing offset value, the first timing adjustment value, the second timing adjustment value, and the third timing offset value;

[0171] The second terminal is synchronized with the first terminal according to the actual timing deviation.

[0172] Further, the calculating, according to the second timing offset value, the first timing adjustment value, the second timing adjustment value, and the third timing offset value, an actual timing deviation between the second terminal and the first terminal includes:

[0173] The actual timing deviation between the two first terminals is calculated according to the following formula:

[0174] R xy =(Ta xy -Ta yx -Td x +Td y -Δt xy +Δt yx ) / 2;

[0175] Where y is the first terminal, x is the second terminal, Rt xy is the actual timing offset between the first terminal and the second terminal; Ta yx is the second timing offset value; Ta xy is the third timing offset value; Td x is the second timing adjustment value; Td y is the first timing adjustment value; Δt yx A timing measurement error determined for the first terminal; Δt xy A timing measurement error is determined for the second terminal.

[0176] Exemplarily, the transmission and measurement process of the timing offset between RSUs is described as follows:

[0177] like Figure 4 As shown, let the propagation distance between RSUx and RSUy be L xy ; Assume that at time i-1, RSUx

[0178] The timing offsets of RSUy and RSUy from the reference clock are T x,i-1 and T y,i-1 , RSUy receives RSUx

[0179] The first synchronization signaling sent, the measured relative timing offset is Ta yx,i-1 , RSUx and RSUy are adjusted by timing Td x,i-1 、Td y,i-1 After that, at time i, the timing offsets of RSUx and RSUy from the reference clock are T x,i and T y,i , RSUy sends the first synchronization signaling, RSUx receives the first synchronization signaling sent by RSUy, and the measured relative timing offset is Ta xy,i .but:

[0180]

[0181]

[0182] Among them, Δt yx,i-1 and Δt xy,iare the timing measurement errors determined for RSUy and RSUx respectively, and c is the speed of light.

[0183] In practical applications, RSUx and RSUy are relatively static, Ta xy,i and Ta yx,i-1 The actual measurement is close to that of T x,i =(T x,i-1 -Td x,i-1 ), T y,i =(T y，i-1 -Td y，i-1 ), then, T x，i-1 =T x，i +Td x，i-1 and T y，i-1 =T y，i +Td y，i-1 Substitute into equation (1), then subtract equation (2) from equation (1), and we get T x，i and T y，i The actual deviation between the two is calculated as follows:

[0184] R xy，i =T x，i -T y，i

[0185] =(Ta xy，i -Ta yx，i-1 -Td x，i-1 +Td y，i-1 -Δt xy，i +Δt yx，i-1 ) / 2

[0186] It can be seen from formula (3) that the actual timing deviation between RSUs can be obtained by transmitting the timing offset value between RSUs and the timing adjustment of RSUs in the first synchronization signaling, thereby achieving synchronization between RSUs and eliminating the propagation distance L between RSUs. xy The impact on timing deviation is improved, and the synchronization accuracy between RSUs is improved.

[0187] In another embodiment, in the above step 22, synchronizing with the first terminal according to the first synchronization signaling includes:

[0188] By receiving the first synchronization signaling sent by the first terminal, the second terminal determines a third timing offset value relative to the first terminal;

[0189] When the second terminal determines to receive the first synchronization signaling, a second timing adjustment value of the second terminal;

[0190] An actual timing deviation between the second terminal and the first terminal is calculated according to the third timing offset value, the second timing adjustment value, and the difference between the second timing offset value and the first timing adjustment value.

[0191] Through this embodiment, the first terminal can send the difference between the second timing offset value and the first timing adjustment value instead of sending the second timing offset value and the first timing adjustment value, and the second terminal can still obtain the actual timing deviation from the first terminal.

[0192] Specifically, the actual timing deviation between the second terminal and the first terminal is calculated according to the following formula (4):

[0193] R xy =(Ta xy -T′a yx -Td x -Δt xy +Δt yx ) / twenty four)

[0194] Among them, T′a yx is the difference between the second timing offset value and the first timing adjustment value; x is the second terminal, y is the first terminal, Rt xy is the actual timing offset between the first terminal and the second terminal; Ta xy is the third timing offset value; Td x is the second timing adjustment value; Δt yx A timing measurement error determined for the first terminal; Δt xy A timing measurement error is determined for the second terminal.

[0195] It should be noted that the derivation process of the above formula (4) is:

[0196] For the above formula (2), T′a xy，i =Ta xy，i -Td x，i , T′a yx，i =Ta yx，i -Td y,i ;

[0197] but,

[0198]

[0199] Then, Rt xy，i =T x，i -T y，i

[0200] =(Ta xy，i -Ta yx，i-1 -Tdx，i-1 +Td y -Δt xy，i +Δt yx，i-1 ) / 2

[0201] =(Ta xy,i -Td x,i-1 -T′a xy，i -Δt xy，i +Δt yx，i-1 ) / 2.

[0202] It can be seen from the above embodiments that when the first terminal sends the difference between the second timing offset value and the first timing adjustment value instead of sending the second timing offset value and the first timing adjustment value, the second terminal can still obtain the actual timing deviation from the first terminal.

[0203] Furthermore, it should be pointed out that each RSU is synchronized with its synchronization source RSU. Due to measurement errors and crystal oscillator errors, there is usually a certain deviation between the synchronization source and the reference time. In the process of keeping consistent with the synchronization source, sometimes there is a misadjustment that deviates from the reference clock, resulting in the accumulation of multi-level synchronization adjustment errors. If the deviation between the RSU and the reference time can be directly obtained, the probability of misadjustment can be effectively reduced, and the accumulation of multi-level synchronization adjustment errors can be reduced.

[0204] Specifically, let T x is the relative offset between the timing of RSUx and the reference time, Rt yx is the actual deviation of RSUy relative to RSUx, then the relative offset value of RSUy and the reference time is Tt y =Tt y =T x -Td x +Tt yx =T x +(Ta yx -Ta xy +Td x -Td y +Δt xy -Δt yx ) / 2

[0205] It can be seen from the above embodiments that, on the basis of eliminating the propagation delay between RSUs and achieving synchronization between RSUs, each RSU periodically broadcasts the offset relative to the reference time, and the RSU can achieve timing adjustment based on the reference time, thereby effectively reducing the probability of misadjustment and reducing the accumulation of multi-level synchronization adjustment errors.

[0206] In one embodiment, the receiving the first synchronization signaling sent by the first terminal through the PSCCH and the direct link shared channel PSSCH includes:

[0207] receiving a first part of the first synchronization signaling sent by the first terminal through the PSCCH; and

[0208] Receiving a second part of the first synchronization signaling sent by the first terminal through the PSSCH;

[0209] The first part is used to indicate whether the PSCCH carries the first synchronization signaling; the PSSCH indicated by the PSCCH carries the second part of the first synchronization signaling, and the second part is used to carry and indicate the synchronization data.

[0210] Specifically, the first part is carried by direct link control information SCI.

[0211] In this embodiment, the first synchronization signaling includes two parts, the first part is carried on the PSCCH, and the second part is carried on the PSSCH. Among them, the industry standard YD / T3755-2020 "Technical requirements for roadside equipment supporting direct communication based on LTE network wireless communication technology" stipulates that the direct link control information SCI adopts SCI format 1, and there are currently at least 7 bits left as padding bits. As an implementation method, the first part of the first synchronization signaling in this embodiment can use the last N bits of SCI in PSCCH: a i 、a i+1 ,……,a i+N-1 It is used to carry and indicate the current subframe number and whether it is synchronization signaling. a j is the value of the jth bit; i=31-N+1. If the value of a is greater than 0, it indicates that the PSCCH carries the first part of the first synchronization signaling, and the PSSCH indicated by the PSCCH carries the second part of the message.

[0212] Exemplarily, the format of the second part of the first synchronization signaling sent by the first RSU (first terminal) may be:

[0213]

[0214] The second timing offset is a timing offset measured by the first RSU relative to the local time (the first RSU) through the synchronization signaling sent by the N nearby RSUs monitored.

[0215] In another embodiment, when the first synchronization signaling is sent through the PSCCH, the format of the first synchronization signaling is:

[0216]

[0217] In one embodiment, the synchronization level of the first terminal includes at least one of the following:

[0218] a first synchronization level, wherein the first synchronization level indicates that a synchronization source of the first terminal is a Global Navigation Satellite System (GNSS) signal;

[0219] The n+1th synchronization level, wherein the n+1th synchronization level indicates that the synchronization source of the first terminal is a terminal of the nth synchronization level; wherein n≥1, and n is a positive integer.

[0220] In this embodiment, the terminal device that uses the GNSS signal for synchronization calibration has the highest synchronization level, which can be recorded as 1, and the synchronization level of the vehicle networking terminal device that is synchronized with the signal source with the synchronization level n is one level lower, which is recorded as n + 1. There may be no direct relationship between the synchronization level between the RSUs and the synchronization level in the signal sent in the PSBCH.

[0221] For the second terminal, synchronization calibration is performed according to the synchronization signaling only when the synchronization level of the source address of the received synchronization signaling is higher than that of the current device by more than one level.

[0222] In one embodiment, the synchronization method further includes:

[0223] receiving a second synchronization signaling sent by the terminal, where the second synchronization signaling is on a direct link broadcast channel PSBCH sent through a reserved subframe;

[0224] The second synchronization signaling is used to indicate the synchronization level of the first terminal; the second synchronization signaling includes: indication information of whether the first terminal device is within the coverage of the GNSS and a direct link synchronization signal index.

[0225] In this embodiment, according to the bitmap mapping, the subframes in the SFN period (10240ms) that cannot be divided by the bitmap are called reserved subframes. The number of reserved subframes N reserved The calculation method is as follows:

[0226] N reserved =(10240-N slss -N dssf )modL bitmap

[0227] Among them, L bitmap N is the bitmap length configured by the higher layer. SLSS N is the number of subframes configured as SLSS resources in 10240 subframes. dssf It is the total number of downlink subframes and special subframes in 10240 subframes when direct link transmission occurs in one TDD cellular cell.

[0228] Specifically, the correspondence between the synchronization level, the indication information, and the through link synchronization signal index includes at least one of the following:

[0229] When the indication information is 1 and the through link synchronization signal index is 0, it indicates that the synchronization level of the first terminal device is the first synchronization level;

[0230] When the indication information is 0 and the direct link synchronization signal index is 0, it indicates that the synchronization level of the first terminal device is not the first synchronization level.

[0231] In this embodiment, when the synchronization source of the first terminal is the GNSS synchronization signal, the indication information: the inCoverage flag is 1, indicating that the local device is within the coverage of the GNSS, and the direct link synchronization signal index (SLSS ID) is 0; when the first terminal is synchronized through the synchronization signaling sent by other terminals (such as RSU), the indication information: the inCoverage flag is 0, indicating that the local device is outside the coverage of the GNSS, and the SLSS ID is 0.

[0232] Combine the following Figure 5 , the synchronization process between RSUs when the first synchronization signaling is sent through PSCCH and PSSCH is introduced.

[0233] Figure 5 The time synchronization process of the second RSU is shown, and the main process includes:

[0234] After the local device (second RSU) is powered on, it first detects whether it can receive GNSS signals. If it can, it updates the local clock according to the GNSS signal and enters the synchronization state with a synchronization level of 1. The local device that enters the synchronization state sends the first synchronization signaling through PSCCH and PSSCH, and sends the second synchronization signaling through PSBCH. The inCoverage flag is 1, indicating that the local device is within the coverage of GNSS, and the SLSS ID is 0.

[0235] If the local device does not receive the GNSS signal, the local device enters the out-of-sync state and receives the first synchronization signaling sent by other devices (the first RSU). If the local device can receive the first synchronization signaling sent by other devices through PSCCH and PSSCH, and the signal power is greater than the threshold setting value, the local device synchronizes with the first synchronization signaling with the highest synchronization level, and the local device enters the synchronization state. The local device sends the first synchronization signaling through PSCCH and PSSCH, and sends the second synchronization signaling through PSBCH. If the synchronization source level of the local device is n, the synchronization level of the local device is n+1, and the inCoverage flag is 0, it means that the local device is not within the coverage of GNSS, and the SLSS ID is 0.

[0236] If the local device does not receive the GNSS signal, the local device enters the out-of-sync state and receives the synchronization signaling sent by other devices. If the local device does not receive the first synchronization signaling sent by other devices through PSCCH and PSSCH, but receives the second synchronization signaling sent by other devices through PSBCH, and the signal power is greater than the threshold setting value, the local device synchronizes with the second synchronization signaling with the highest synchronization level, and the local device enters the synchronization state. The inCoverage flag is 0, indicating that the local device is not within the coverage of GNSS, the SLSS ID is 0, and no synchronization signaling is sent.

[0237] If the local device does not receive the GNSS signal, the local device enters the out-of-sync state and receives the synchronization signaling sent by other devices. If the local device does not receive the first synchronization signaling sent by other devices through PSCCH and PSSCH, and does not receive the second synchronization signaling sent by other devices through PSBCH, the local device enters the out-of-sync state, the inCoverage flag is 0, indicating that the local device is not within the coverage of GNSS, and the SLSS ID is a random number greater than 168, indicating that the local device has no synchronization source. According to the pre-setting, no synchronization signaling is sent.

[0238] Combine the following Figure 6 , the synchronization process between RSUs when the first synchronization signaling is sent through PSCCH is introduced.

[0239] Figure 6 The time synchronization process of the second RSU is shown.

[0240] After the local device (second RSU) is powered on, it first detects whether it can receive GNSS signals. If it can, it updates the local clock according to the GNSS signal and enters the synchronization state with a synchronization level of 1. The local device that enters the synchronization state sends the first synchronization signaling through PSCCH and the second synchronization signaling through PSBCH. The inCoverage flag is 1, indicating that the local device is within the coverage of GNSS, and the SLSS ID is 0.

[0241] If the local device does not receive the GNSS signal, the local device enters the out-of-sync state and receives the first synchronization signaling sent by other devices (the first RSU). If the local device can receive the first synchronization signaling sent by other devices through PSCCH, and the signal power is greater than the threshold setting value, the local device synchronizes with the first synchronization signaling with the highest synchronization level, and the local device enters the synchronization state. The local device sends the first synchronization signaling through PSCCH and the second synchronization signaling through PSBCH. If the synchronization source level of the local device is n, the synchronization level of the local device is n+1, and the inCoverage flag is 0, it means that the local device is not within the coverage of GNSS, and the SLSS ID is 0.

[0242] If the local device does not receive the GNSS signal, the local device enters the out-of-sync state and receives the synchronization signaling sent by other devices. If the local device does not receive the first synchronization signaling sent by other devices through PSCCH, but receives the second synchronization signaling sent by other devices through PSBCH, and the signal power is greater than the threshold setting value, the local device synchronizes with the second synchronization signaling with the highest synchronization level, and the local device enters the synchronization state. The inCoverage flag is 0, indicating that the local device is not within the coverage of GNSS, the SLSS ID is 0, and no synchronization signaling is sent.

[0243] If the local device does not receive the GNSS signal, the local device enters the out-of-sync state and receives the synchronization signaling sent by other devices. If the local device does not receive the first synchronization signaling sent by other devices through PSCCH, nor does it receive the second synchronization signaling sent by other devices through PSBCH, the local device enters the out-of-sync state, the inCoverage flag is 0, indicating that the local device is not within the coverage of GNSS, and the SLSS ID is a random number greater than 168, indicating that the local device has no synchronization source. According to the pre-setting, no synchronization signaling is sent.

[0244] Next, combine Figures 7 to 8 The application scenarios of the synchronization method between RSUs are introduced.

[0245] Example 1: When the local device receives multiple synchronization signals at the same time, this embodiment uses Figure 7Take an example for explanation. RSU2 receives the first synchronization signaling from RSU1 and RSU3 respectively, where the synchronization signal power of RSU1 is P1, the synchronization level is n1, the inCoverage flag is 0, and the SLSS ID is 0; the synchronization signal power of RSU3 is P3, the synchronization level is n3, the inCoverage flag is 0, and the SLSS ID is 0. And both P1 and P3 are greater than the power threshold. n1<n3, RSU2 is synchronized with RSU1, the synchronization level is n1+1, the inCoverage flag is 0, and the SLSS ID is 0. RSU2 measures the timing offset with RSU1 and RSU3, and sends the first synchronization signaling through PSCCH and PSSCH, and sends the second synchronization signaling through PSBCH.

[0246] Example 2, such as Figure 8 As shown, the timings of RSU1 and RSU2 are T1 and T2 respectively. RSU1 sends the first synchronization signaling to RSU2, and the measured relative timing offset is Ta. 21 Then, RSU2 sends the first synchronization signaling to RSU1. RSU1 receives the first synchronization signaling sent by RSU2 and measures the relative timing offset as Ta. 12 If the offset between RSU1 and the reference time is Rt1, and the timing adjustment is Td1, then the offset between RSU2 and the reference time can be set to:

[0247] Rt2=Rt1-(Ta 21 -Ta 12 -Td2+Td1+Δt 12 -Δt 21 ) / 2

[0248] Among them, Δt 12 and Δt 21 They are the measurement errors of RSU1 and RSU2, respectively, which can be eliminated by smoothing filtering.

[0249] Third embodiment

[0250] like Fig. 9 As shown, the third embodiment of the present invention provides a synchronization method, which is applied to a third terminal. Optionally, the third terminal is an on-board device OBU or a vulnerable road user (Vulnerable Roas Users, VRU). The synchronization method specifically includes the following steps:

[0251] Step 31: receiving a pilot signal and a first synchronization signaling sent by at least one first terminal;

[0252] The first synchronization signaling is used to indicate at least one of the following synchronization data:

[0253] a synchronization level of the first terminal;

[0254] The radio frame and subframe number corresponding to the first synchronization signaling;

[0255] The identity ID of the first terminal;

[0256] a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling;

[0257] a first timing adjustment value, where the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling;

[0258] a second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal;

[0259] a difference between the first timing offset value and the first timing adjustment value;

[0260] The difference between the second timing offset value and the first timing adjustment value.

[0261] In this step, receiving a pilot signal and a first synchronization signaling sent by a first terminal includes:

[0262] Receiving the first synchronization signaling sent by the first terminal through the direct link control channel PSCCH; or

[0263] The first synchronization signaling is received by the first terminal through the PSCCH and the direct link shared channel PSSCH; wherein the pilot signal is a demodulation reference signal (DeModulation Reference Signal, referred to as DMRS).

[0264] It should be pointed out that for LTE-V2X systems and NR-V2X systems, when PSCCH transmission is performed, DMRS signals are sent at the same time, which can be used for PSCCH channel detection on the receiving side; when PSSCH transmission is performed, DMRS signals are sent at the same time, which can be used for PSSCH channel detection on the receiving side.

[0265] Step 32: performing synchronization processing with the first terminal with the highest synchronization level according to the first synchronization signaling sent by the first terminal with the highest synchronization level;

[0266] In this embodiment, when the third terminal (OBU) receives the first synchronization signaling sent by multiple first terminals (RSU), it selects the first synchronization signaling with the highest synchronization level among the first terminals for synchronization.

[0267] In one embodiment, the synchronization method further includes:

[0268] receiving a second synchronization signaling sent by the terminal, where the second synchronization signaling is on a direct link broadcast channel PSBCH sent through a reserved subframe;

[0269] The second synchronization signaling is used to indicate the synchronization level of the first terminal; the second synchronization signaling includes: indication information of whether the first terminal device is within the coverage of the GNSS and a direct link synchronization signal index.

[0270] In this embodiment, according to the bitmap mapping, the subframes in the SFN period (10240ms) that cannot be divided by the bitmap are called reserved subframes. The number of reserved subframes N reserved The calculation method is as follows:

[0271] N reserved =(10240-N slss -N dssf )modL bitmap

[0272] Among them, L bitmap N is the bitmap length configured by the higher layer. SLSS N is the number of subframes configured as SLSS resources in 10240 subframes. dssf It is the total number of downlink subframes and special subframes in 10240 subframes when direct link transmission occurs in one TDD cellular cell.

[0273] Specifically, the correspondence between the synchronization level, the indication information, and the through link synchronization signal index includes at least one of the following:

[0274] When the indication information is 1 and the through link synchronization signal index is 0, it indicates that the synchronization level of the first terminal device is the first synchronization level;

[0275] When the indication information is 0 and the direct link synchronization signal index is 0, it indicates that the synchronization level of the first terminal device is not the first synchronization level.

[0276] In this embodiment, when the synchronization source of the first terminal is the GNSS synchronization signal, the indication information: the inCoverage flag is 1, indicating that the local device is within the coverage of the GNSS, and the direct link synchronization signal index (SLSS ID) is 0; when the first terminal is synchronized through the synchronization signaling sent by other terminals (such as RSU), the indication information: the inCoverage flag is 0, indicating that the local device is outside the coverage of the GNSS, and the SLSS ID is 0.

[0277] Combine the following Fig.10 , the synchronization process of OBU is introduced.

[0278] like Fig.10 As shown in the figure, the system parameter configuration of the Internet of Vehicles terminal devices such as RSU and OBU is as follows: the system bandwidth is 20MHz, half-duplex mode is supported, the subcarrier spacing is 15kHz, the cyclic prefix (CP) length is 4.687μs (5.208μs (symbol 0)), the modulation mode is QPSK, and the maximum transmission power is 23dBm.

[0279] like Fig.10 As shown in the figure, a vehicle networking application scenario includes 4 RSUs and 1 OBU, of which only RSU1 can receive GNSS signals. The initial states of the 4 RSUs and 1 OBU are all out of sync. After startup, they first receive GNSS signals and do not send synchronization signaling. RSU1 receives the GNSS signal and enters the synchronization state with a synchronization level of 1. RSU1 sends the first synchronization signaling through PSCCH and PSSCH, and sends the second synchronization signaling through PSBCH. The inCoverage flag is 1 and the SLSS ID is 0. RSU2 receives the first synchronization signaling sent by RSU1 and enters the synchronization state with a synchronization level of 2. RSU2 sends the first synchronization signaling through PSCCH and PSSCH, and sends the second synchronization signaling through PSBCH. The inCoverage flag is 0 and the SLSS ID is 0. RSU3 receives the first synchronization signaling sent by RSU2 and enters the synchronization state with a synchronization level of 3. RSU3 sends the first synchronization signaling through PSCCH and PSSCH, and sends the second synchronization signaling through PSBCH, the inCoverage flag is 0, and the SLSS ID is 0. RSU4 receives the first synchronization signaling sent by RSU3 and enters the synchronization state, and the synchronization level is 4. RSU4 sends the first synchronization signaling through PSCCH and PSSCH, and sends the second synchronization signaling through PSBCH, the inCoverage flag is 0, and the SLSS ID is 0. OBU1 receives the first synchronization signaling or the second synchronization signaling sent by RSU3 and enters the synchronization state.

[0280] Fourth embodiment

[0281] like Fig.11 As shown, an embodiment of the present invention provides a synchronization device 1100, which is applied to a first terminal and includes:

[0282] The first sending module 1101 is configured to send a pilot signal and a first synchronization signaling; wherein the first synchronization signaling is used to indicate at least one of the following synchronization data:

[0283] a synchronization level of the first terminal;

[0284] The radio frame and subframe number corresponding to the first synchronization signaling;

[0285] The identity ID of the first terminal;

[0286] a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling;

[0287] A timing adjustment value, wherein the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling;

[0288] a second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal;

[0289] a difference between the first timing offset value and the first timing adjustment value;

[0290] The difference between the second timing offset value and the first timing adjustment value.

[0291] Optionally, the first sending module 1101 includes:

[0292] A first sending submodule is configured to send the first synchronization signaling via a direct link control channel PSCCH; or

[0293] A second sending submodule, used for sending the first synchronization signaling through the PSCCH and the direct link shared channel PSSCH;

[0294] The pilot signal is a demodulation reference signal DMRS.

[0295] Optionally, the second sending submodule includes:

[0296] A first sending unit, configured to send a first part of the first synchronization signaling through a PSCCH; and

[0297] A second sending unit, configured to send a second part of the first synchronization signaling through a PSSCH;

[0298] The first part is used to indicate whether the PSCCH carries the first synchronization signaling; the PSSCH indicated by the PSCCH carries the second part of the first synchronization signaling, and the second part is used to indicate the synchronization data.

[0299] Optionally, the first part is carried by direct link control information SCI.

[0300] Optionally, the synchronization level of the first terminal includes at least one of the following:

[0301] A first synchronization level, wherein the first synchronization level indicates that a synchronization source of the first terminal is a Global Navigation Satellite System GNSS signal;

[0302] The n+1th synchronization level, wherein the n+1th synchronization level indicates that the synchronization source of the first terminal is a terminal of the nth synchronization level; wherein n≥1, and n is a positive integer.

[0303] Optionally, the device 1100 further includes:

[0304] A second sending module, configured to send a second synchronization signaling on a direct link broadcast channel PSBCH sent through a reserved subframe;

[0305] The second synchronization signaling is used to indicate the synchronization level of the first terminal; the second synchronization signaling includes: indication information of whether the first terminal device is within the coverage of the GNSS and a direct link synchronization signal index.

[0306] Optionally, the correspondence between the synchronization level, the indication information, and the through link synchronization signal index includes at least one of the following:

[0307] When the indication information is 1 and the through link synchronization signal index is 0, it indicates that the synchronization level of the first terminal device is the first synchronization level;

[0308] When the indication information is 0 and the direct link synchronization signal index is 0, it indicates that the synchronization level of the first terminal device is not the first synchronization level.

[0309] The fourth embodiment of the present invention corresponds to the method of the first embodiment. All implementation means in the first embodiment are applicable to the embodiment of the synchronization device 1100 and can achieve the same technical effect.

[0310] Fifth embodiment

[0311] like Fig.12 As shown, a synchronization device 1200 according to an embodiment of the present invention is applied to a second terminal, and the device 1200 includes:

[0312] The first receiving module 1201 is used to receive a pilot signal and a first synchronization signaling sent by a first terminal;

[0313] A first synchronization processing module 1202, configured to synchronize with the first terminal according to the first synchronization signaling when the synchronization level of the first terminal is higher than the synchronization level of the second terminal;

[0314] The first synchronization signaling is used to indicate at least one of the following synchronization data:

[0315] a synchronization level of the first terminal;

[0316] The radio frame and subframe number corresponding to the first synchronization signaling;

[0317] The identity ID of the first terminal;

[0318] a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling;

[0319] a first timing adjustment value, where the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling;

[0320] a second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal;

[0321] a difference between the first timing offset value and the first timing adjustment value;

[0322] The difference between the second timing offset value and the first timing adjustment value.

[0323] Optionally, the first receiving module 1201 includes:

[0324] A first receiving submodule is configured to receive the first synchronization signaling sent by the first terminal via a direct link control channel PSCCH; or

[0325] A second receiving submodule, configured to receive the first synchronization signaling sent by the first terminal through the PSCCH and the direct link shared channel PSSCH;

[0326] The pilot signal is a demodulation reference signal DMRS.

[0327] Optionally, the second receiving submodule includes:

[0328] A first receiving unit, configured to receive a first part of the first synchronization signaling sent by the first terminal through the PSCCH; and

[0329] A second receiving unit, configured to receive a second part of the first synchronization signaling sent by the first terminal through the PSSCH;

[0330] The first part is used to indicate whether the PSCCH carries the first synchronization signaling; the PSSCH indicated by the PSCCH carries the second part of the first synchronization signaling, and the second part is used to carry and indicate the synchronization data.

[0331] Optionally, the first part is carried by direct link control information SCI.

[0332] Optionally, the synchronization level of the first terminal includes at least one of the following:

[0333] A first synchronization level, wherein the first synchronization level indicates that a synchronization source of the first terminal is a Global Navigation Satellite System GNSS signal;

[0334] The n+1th synchronization level, wherein the n+1th synchronization level indicates that the synchronization source of the first terminal is a terminal of the nth synchronization level; wherein n≥1, and n is a positive integer.

[0335] Optionally, the first synchronization processing module 1202 includes:

[0336] A first processing submodule, configured to, by receiving the first synchronization signaling sent by the first terminal, enable the second terminal to determine a third timing offset value relative to the first terminal;

[0337] A second processing submodule, configured to determine a second timing adjustment value of the second terminal when receiving the first synchronization signaling;

[0338] A third processing submodule, configured to calculate an actual timing deviation between the second terminal and the first terminal according to the second timing offset value, the first timing adjustment value, the second timing adjustment value and the third timing offset value;

[0339] A fourth processing submodule is configured to synchronize the second terminal with the first terminal according to the actual timing deviation.

[0340] Optionally, the third processing submodule includes:

[0341] The first processing unit is configured to calculate an actual timing deviation between the two first terminals according to the following formula:

[0342] R xy =(Ta xy -Ta yx -Td x +Td y +Δt yx -Δt xy ) / 2;

[0343] Where x is the second terminal, y is the first terminal, Rt xy is the actual timing offset between the first terminal and the second terminal; Ta yx is the second timing offset value; Ta xy is the third timing offset value; Td x is the second timing adjustment value; Td y is the first timing adjustment value; Δt yxA timing measurement error determined for the first terminal; Δt xy A timing measurement error is determined for the second terminal.

[0344] Optionally, the above device 1200 further includes:

[0345] A second receiving module, configured to receive a second synchronization signaling sent by the terminal, where the second synchronization signaling is on a direct link broadcast channel PSBCH sent through a reserved subframe;

[0346] The second synchronization signaling is used to indicate the synchronization level of the first terminal; the second synchronization signaling includes: indication information of whether the first terminal device is within the coverage of the GNSS and a direct link synchronization signal index.

[0347] Optionally, the correspondence between the synchronization level, the indication information, and the through link synchronization signal index includes at least one of the following:

[0348] When the indication information is 1 and the through link synchronization signal index is 0, it indicates that the synchronization level of the first terminal device is the first synchronization level;

[0349] When the indication information is 0 and the direct link synchronization signal index is 0, it indicates that the synchronization level of the first terminal device is not the first synchronization level.

[0350] The synchronization device 1200 is a device corresponding to the method in the second embodiment. All implementation means in the above method embodiment are applicable to the embodiment of the synchronization device 1200 and can achieve the same technical effect.

[0351] Sixth embodiment

[0352] like Fig.13 As shown, a synchronization device 1300 according to an embodiment of the present invention is applied to a third terminal, and the device 900 includes:

[0353] The third receiving module 1301 is used to receive a pilot signal and a first synchronization signaling sent by at least one first terminal;

[0354] A second synchronization processing module 1302 is configured to synchronize with the first terminal with the highest synchronization level according to the first synchronization signaling sent by the first terminal with the highest synchronization level;

[0355] The first synchronization signaling is used to indicate at least one of the following synchronization data:

[0356] a synchronization level of the first terminal;

[0357] The radio frame and subframe number corresponding to the first synchronization signaling;

[0358] The identity ID of the first terminal;

[0359] a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling;

[0360] a first timing adjustment value, where the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling;

[0361] a second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal;

[0362] a difference between the first timing offset value and the first timing adjustment value;

[0363] The difference between the second timing offset value and the first timing adjustment value.

[0364] The synchronization device 1300 is a device corresponding to the method in the second embodiment. All implementation means in the above method embodiment are applicable to the embodiment of the synchronization device and can achieve the same technical effect.

[0365] Seventh embodiment

[0366] In order to better achieve the above goals, Fig.14 As shown, the sixth embodiment of the present invention further provides a terminal, which is a first terminal, including:

[0367] A processor 1400; and a memory 1420 connected to the processor 1400 via a bus interface, wherein the memory 1420 is used to store programs and data used by the processor 1400 when performing operations, and the processor 1400 calls and executes the programs and data stored in the memory 1420.

[0368] The transceiver 1410 is connected to the bus interface and is used to receive and send data under the control of the processor 1400 ; the processor 1400 is used to read the program in the memory 1420 .

[0369] Specifically, the transceiver 1410 is used to send a pilot signal and a first synchronization signaling; wherein the first synchronization signaling is used to indicate at least one of the following synchronization data:

[0370] a synchronization level of the first terminal;

[0371] The radio frame and subframe number corresponding to the first synchronization signaling;

[0372] The identity ID of the first terminal;

[0373] a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling;

[0374] a first timing adjustment value, where the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling;

[0375] a second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal;

[0376] a difference between the first timing offset value and the first timing adjustment value;

[0377] The difference between the second timing offset value and the first timing adjustment value.

[0378] Among them, Fig.14 In the embodiment, the bus architecture may include any number of interconnected buses and bridges, specifically linking together various circuits of one or more processors represented by processor 1400 and memory represented by memory 1420. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface. The transceiver 1410 may be a plurality of components, namely, a transmitter and a transceiver, providing a unit for communicating with various other devices on a transmission medium. The processor 1400 is responsible for managing the bus architecture and general processing, and the memory 1420 may store data used by the processor 1400 when performing operations.

[0379] Optionally, the transceiver 1410 is specifically configured to send the first synchronization signaling via a direct link control channel PSCCH; or

[0380] Sending the first synchronization signaling via PSCCH and direct link shared channel PSSCH;

[0381] The pilot signal is a demodulation reference signal DMRS.

[0382] Optionally, when the transceiver 1410 sends the first synchronization signaling through the PSCCH and the direct link shared channel PSSCH, it is specifically used to send the first part of the first synchronization signaling through the PSCCH; and send the second part of the first synchronization signaling through the PSSCH;

[0383] The first part is used to indicate whether the PSCCH carries the first synchronization signaling; the PSSCH indicated by the PSCCH carries the second part of the first synchronization signaling, and the second part is used to indicate the synchronization data.

[0384] Optionally, the first part is carried by direct link control information SCI.

[0385] Optionally, the synchronization level of the first terminal includes at least one of the following:

[0386] A first synchronization level, wherein the first synchronization level indicates that a synchronization source of the first terminal is a Global Navigation Satellite System GNSS signal;

[0387] The n+1th synchronization level, wherein the n+1th synchronization level indicates that the synchronization source of the first terminal is a terminal of the nth synchronization level; wherein n≥1, and n is a positive integer.

[0388] Optionally, the transceiver 1410 is further configured to send a second synchronization signaling on a direct link broadcast channel PSBCH sent through a reserved subframe;

[0389] The second synchronization signaling is used to indicate the synchronization level of the first terminal; the second synchronization signaling includes: indication information of whether the first terminal device is within the coverage of the GNSS and a direct link synchronization signal index.

[0390] Optionally, the correspondence between the synchronization level, the indication information, and the through link synchronization signal index includes at least one of the following:

[0391] When the indication information is 1 and the through link synchronization signal index is 0, it indicates that the synchronization level of the first terminal device is the first synchronization level;

[0392] When the indication information is 0 and the direct link synchronization signal index is 0, it indicates that the synchronization level of the first terminal device is not the first synchronization level.

[0393] The first terminal provided by the present invention sends a pilot signal and a first synchronization signaling; and realizes synchronization processing by other vehicle networking terminals by receiving the pilot signal and the first synchronization signaling sent by the first terminal. When the other vehicle networking terminals are RSUs, the RSU receives the pilot signal and the first synchronization signaling sent by the first terminal, and when it is determined that the synchronization level of the first terminal is higher than its own, it can synchronize with the first terminal according to the first timing adjustment value and the second timing offset value; or synchronize with the synchronization source while synchronizing with the first terminal according to the first timing adjustment value, the second timing offset value and the first timing offset value; or synchronize with the first terminal according to the difference between the second timing offset value and the first timing adjustment value, or synchronize with the synchronization source while synchronizing with the first terminal according to the difference between the first timing offset value and the first timing adjustment value and the difference between the second timing offset value and the first timing adjustment value. When other Internet of Vehicles terminals are OBUs, the OBU receives a pilot signal and a first synchronization signaling sent by at least one first terminal; and performs synchronization processing with the first terminal with the highest synchronization level according to the first synchronization signaling sent by the first terminal with the highest synchronization level; therefore, this embodiment can achieve synchronous coordination between Internet of Vehicles terminals even when time synchronization cannot be performed through satellite signals and the internal clock accuracy of the Internet of Vehicles equipment is low and cannot meet the requirements of high-precision time synchronization for a long time, and can solve the problem of difficult synchronous coordination between Internet of Vehicles terminals under the distributed architecture of the Internet of Vehicles.

[0394] Those skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware, or may be accomplished by instructing relevant hardware through a computer program, wherein the computer program includes instructions for executing part or all of the steps of the above method; and the computer program may be stored in a readable storage medium, and the storage medium may be any form of storage medium.

[0395] Eighth embodiment

[0396] In order to better achieve the above goals, Fig.15 As shown, the sixth embodiment of the present invention further provides a terminal, which is a second terminal, including:

[0397] A processor 1500; and a memory 1520 connected to the processor 1500 via a bus interface, wherein the memory 1520 is used to store programs and data used by the processor 1500 when performing operations, and the processor 1500 calls and executes the programs and data stored in the memory 1520.

[0398] The transceiver 1510 is connected to the bus interface and is used to receive and send data under the control of the processor 1500 ; the processor 1500 is used to read the program in the memory 1520 .

[0399] Specifically, the transceiver 1510 is used to receive a pilot signal and a first synchronization signaling sent by a first terminal;

[0400] The processor 1500 is configured to, when a synchronization level of the first terminal is higher than a synchronization level of the second terminal, synchronize with the first terminal according to the first synchronization signaling;

[0401] The first synchronization signaling is used to indicate at least one of the following synchronization data:

[0402] a synchronization level of the first terminal;

[0403] The radio frame and subframe number corresponding to the first synchronization signaling;

[0404] The identity ID of the first terminal;

[0405] a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling;

[0406] a first timing adjustment value, where the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling;

[0407] a second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal;

[0408] a difference between the first timing offset value and the first timing adjustment value;

[0409] The difference between the second timing offset value and the first timing adjustment value.

[0410] Among them, Fig.15In the embodiment, the bus architecture may include any number of interconnected buses and bridges, specifically linking together various circuits of one or more processors represented by processor 1500 and memory represented by memory 1520. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface. The transceiver 1510 may be a plurality of components, namely, a transmitter and a transceiver, providing a unit for communicating with various other devices on a transmission medium. The processor 1500 is responsible for managing the bus architecture and general processing, and the memory 1520 may store data used by the processor 1500 when performing operations.

[0411] Optionally, the transceiver 1510 is specifically configured to receive the first synchronization signaling sent by the first terminal through a direct link control channel PSCCH; or

[0412] Receiving the first synchronization signaling sent by the first terminal through the PSCCH and the direct link shared channel PSSCH;

[0413] The pilot signal is a demodulation reference signal DMRS.

[0414] Optionally, when receiving the first synchronization signaling sent by the first terminal through the PSCCH and the direct link shared channel PSSCH, the transceiver 1510 is specifically used to receive a first part of the first synchronization signaling sent by the first terminal through the PSCCH; and receive a second part of the first synchronization signaling sent by the first terminal through the PSSCH;

[0415] The first part is used to indicate whether the PSCCH carries the first synchronization signaling; the PSSCH indicated by the PSCCH carries the second part of the first synchronization signaling, and the second part is used to carry and indicate the synchronization data.

[0416] Optionally, the first part is carried by direct link control information SCI.

[0417] Optionally, the synchronization level of the first terminal includes at least one of the following:

[0418] A first synchronization level, wherein the first synchronization level indicates that a synchronization source of the first terminal is a Global Navigation Satellite System GNSS signal;

[0419] The n+1th synchronization level, wherein the n+1th synchronization level indicates that the synchronization source of the first terminal is a terminal of the nth synchronization level; wherein n≥1, and n is a positive integer.

[0420] Optionally, the processor 1500 is specifically configured to, by receiving the first synchronization signaling sent by the first terminal, determine, by the second terminal, a third timing offset value relative to the first terminal;

[0421] determining a second timing adjustment value of the second terminal when receiving the first synchronization signaling;

[0422] Calculate an actual timing deviation between the second terminal and the first terminal according to the second timing offset value, the first timing adjustment value, the second timing adjustment value, and the third timing offset value;

[0423] The second terminal is synchronized with the first terminal according to the actual timing deviation.

[0424] Optionally, when the processor 1500 calculates an actual timing deviation between the second terminal and the first terminal according to the second timing offset value, the first timing adjustment value, the second timing adjustment value, and the third timing offset value, the processor 1500 is specifically configured to:

[0425] The actual timing deviation between the two first terminals is calculated according to the following formula:

[0426] R xy =(Ta xy -Ta yx -Td x +Td y +Δt yx -Δt xy ) / 2;

[0427] Where x is the second terminal, y is the first terminal, Rt xy is the actual timing offset between the first terminal and the second terminal; Ta yx is the second timing offset value; Ta xy is the third timing offset value; Td x is the second timing adjustment value; Td y is the first timing adjustment value; Δt yx A timing measurement error determined for the first terminal; Δt xy A timing measurement error is determined for the second terminal.

[0428] Optionally, the transceiver 1510 is further configured to: receive a second synchronization signaling sent by the terminal, where the second synchronization signaling is on a direct link broadcast channel PSBCH sent through a reserved subframe;

[0429] The second synchronization signaling is used to indicate the synchronization level of the first terminal; the second synchronization signaling includes: indication information of whether the first terminal device is within the coverage of the GNSS and a direct link synchronization signal index.

[0430] Optionally, the correspondence between the synchronization level, the indication information, and the through link synchronization signal index includes at least one of the following:

[0431] When the indication information is 1 and the through link synchronization signal index is 0, it indicates that the synchronization level of the first terminal device is the first synchronization level;

[0432] When the indication information is 0 and the direct link synchronization signal index is 0, it indicates that the synchronization level of the first terminal device is not the first synchronization level.

[0433] The second terminal provided by the present invention can realize synchronization and coordination between RSUs even when time synchronization cannot be performed through satellite signals and the internal clock accuracy of the Internet of Vehicles equipment is low and cannot meet the requirements of high-precision time synchronization for a long time. It can also eliminate the influence of propagation distance on timing, which is conducive to improving the synchronization accuracy between RSUs.

[0434] Ninth embodiment

[0435] In order to better achieve the above goals, Fig.16 As shown, the ninth embodiment of the present invention further provides a terminal, which is a second terminal, including:

[0436] A processor 1600; and a memory 1620 connected to the processor 1600 via a bus interface, wherein the memory 1620 is used to store programs and data used by the processor 1600 when performing operations, and the processor 1600 calls and executes the programs and data stored in the memory 1120.

[0437] The transceiver 1610 is connected to the bus interface and is used to receive and send data under the control of the processor 1600 ; the processor 1600 is used to read the program in the memory 1620 .

[0438] Specifically, the transceiver 1610 is used to receive a pilot signal and a first synchronization signaling sent by at least one first terminal;

[0439] The processor 1600 is configured to synchronize with the first terminal with the highest synchronization level according to the first synchronization signaling sent by the first terminal with the highest synchronization level;

[0440] The first synchronization signaling is used to indicate at least one of the following synchronization data:

[0441] a synchronization level of the first terminal;

[0442] The radio frame and subframe number corresponding to the first synchronization signaling;

[0443] The identity ID of the first terminal;

[0444] a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling;

[0445] a first timing adjustment value, where the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling;

[0446] a second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal;

[0447] a difference between the first timing offset value and the first timing adjustment value;

[0448] The difference between the second timing offset value and the first timing adjustment value.

[0449] Among them, Fig.16 In the embodiment, the bus architecture may include any number of interconnected buses and bridges, specifically one or more processors represented by processor 1600 and various circuits of memory represented by memory 1620 are linked together. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and are therefore not further described herein. The bus interface provides an interface. The transceiver 1610 may be a plurality of components, namely, a transmitter and a transceiver, providing a unit for communicating with various other devices on a transmission medium. For different terminals, the user interface 1630 may also be an interface capable of externally connecting or internally connecting required devices, and the connected devices include but are not limited to a keypad, a display, a speaker, a microphone, a joystick, and the like. The processor 1600 is responsible for managing the bus architecture and general processing, and the memory 1620 may store data used by the processor 1600 when performing operations.

[0450] The third terminal provided by the present invention, when receiving the first synchronization signaling sent by multiple first terminals (RSU), selects the first synchronization signaling with the highest synchronization level among the first terminals for synchronization, thereby realizing the synchronization processing process.

[0451] Those skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware, or may be accomplished by instructing relevant hardware through a computer program, wherein the computer program includes instructions for executing part or all of the steps of the above method; and the computer program may be stored in a readable storage medium, and the storage medium may be any form of storage medium.

[0452] In addition, a specific embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored, and when the program is executed by a processor, the steps of the method in the first embodiment, the second embodiment, or the third embodiment are implemented. And the same technical effect can be achieved, so it will not be repeated here to avoid repetition.

[0453] In addition, it should be noted that in the apparatus and method of the present invention, it is obvious that each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent schemes of the present invention. Moreover, the steps of performing the above-mentioned series of processing can naturally be performed in chronological order according to the order of description, but it is not necessary to perform them in chronological order, and some steps can be performed in parallel or independently of each other. For those of ordinary skill in the art, it is understood that all or any steps or components of the method and apparatus of the present invention can be implemented in any computing device (including processors, storage media, etc.) or a network of computing devices in hardware, firmware, software or a combination thereof, which can be achieved by those of ordinary skill in the art using their basic programming skills after reading the description of the present invention.

[0454] Therefore, the purpose of the present invention can also be achieved by running a program or a group of programs on any computing device. The computing device can be a well-known general device. Therefore, the purpose of the present invention can also be achieved by simply providing a program product containing a program code that implements the method or device. That is to say, such a program product also constitutes the present invention, and the storage medium storing such a program product also constitutes the present invention. Obviously, the storage medium can be any well-known storage medium or any storage medium developed in the future. It should also be pointed out that in the device and method of the present invention, it is obvious that each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent schemes of the present invention. In addition, the steps of performing the above-mentioned series of processing can naturally be performed in chronological order according to the order of description, but it is not necessary to perform them in chronological order. Some steps can be performed in parallel or independently of each other.

[0455] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A synchronization method, characterized in that: Applied to a first terminal, the method includes: Sending a pilot signal and a first synchronization signaling, where the first synchronization signaling is used for other terminals to synchronize with the first terminal; wherein the first synchronization signaling is used to indicate the following synchronization data: a synchronization level of the first terminal; a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling; a first timing adjustment value, where the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling; The second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal.

2. The synchronization method according to claim 1, characterized in that: The sending of the pilot signal and the first synchronization signaling includes: Sending the first synchronization signaling via a direct link control channel PSCCH; or Sending the first synchronization signaling via PSCCH and direct link shared channel PSSCH; The pilot signal is a demodulation reference signal DMRS.

3. The synchronization method according to claim 2, characterized in that: The sending the first synchronization signaling through the PSCCH and the direct link shared channel PSSCH includes: Sending a first part of the first synchronization signaling via PSCCH; and Sending a second part of the first synchronization signaling via PSSCH; The first part is used to indicate whether the PSCCH carries the first synchronization signaling; the PSSCH indicated by the PSCCH carries the second part of the first synchronization signaling, and the second part is used to indicate the synchronization data.

4. The synchronization method according to claim 3, characterized in that: The first part is carried by direct link control information SCI.

5. The synchronization method according to claim 1, characterized in that: The synchronization level of the first terminal includes at least one of the following: A first synchronization level, wherein the first synchronization level indicates that a synchronization source of the first terminal is a Global Navigation Satellite System GNSS signal; The n+1th synchronization level, wherein the n+1th synchronization level indicates that the synchronization source of the first terminal is a terminal of the nth synchronization level; wherein n≥1, and n is a positive integer.

6. The synchronization method according to claim 1, characterized in that: Also includes: Sending a second synchronization signaling on a direct link broadcast channel PSBCH sent through a reserved subframe; Among them, the second synchronization signaling is used to indicate the synchronization level of the first terminal; the second synchronization signaling includes: indication information of whether the first terminal device is within the coverage of the GNSS and the direct link synchronization signal index.

7. The synchronization method according to claim 6, characterized in that: The correspondence between the synchronization level, the indication information, and the through link synchronization signal index includes at least one of the following: When the indication information is 1 and the through link synchronization signal index is 0, it indicates that the synchronization level of the first terminal device is the first synchronization level; When the indication information is 0 and the direct link synchronization signal index is 0, it indicates that the synchronization level of the first terminal device is not the first synchronization level.

8. A synchronization method, characterized in that: Applied to the second terminal, the method includes: Receiving a pilot signal and a first synchronization signaling sent by a first terminal; When the synchronization level of the first terminal is higher than the synchronization level of the second terminal, synchronizing with the first terminal according to the first synchronization signaling; The first synchronization signaling is used to indicate the following synchronization data: a synchronization level of the first terminal; a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling; a first timing adjustment value, where the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling; a second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal; The step of synchronizing with the first terminal according to the first synchronization signaling includes: By receiving the first synchronization signaling sent by the first terminal, the second terminal determines a third timing offset value relative to the first terminal; determining a second timing adjustment value of the second terminal when receiving the first synchronization signaling; Calculate an actual timing deviation between the second terminal and the first terminal according to the second timing offset value, the first timing adjustment value, the second timing adjustment value, and the third timing offset value; The second terminal is synchronized with the first terminal according to the actual timing deviation.

9. The synchronization method according to claim 8, characterized in that: The receiving a pilot signal and a first synchronization signaling sent by the first terminal includes: Receiving the first synchronization signaling sent by the first terminal through the direct link control channel PSCCH; or Receiving the first synchronization signaling sent by the first terminal through the PSCCH and the direct link shared channel PSSCH; The pilot signal is a demodulation reference signal DMRS.

10. The synchronization method according to claim 9, characterized in that: The receiving the first synchronization signaling sent by the first terminal through the PSCCH and the direct link shared channel PSSCH includes: receiving a first part of the first synchronization signaling sent by the first terminal through the PSCCH; and Receiving a second part of the first synchronization signaling sent by the first terminal through the PSSCH; The first part is used to indicate whether the PSCCH carries the first synchronization signaling; the PSSCH indicated by the PSCCH carries the second part of the first synchronization signaling, and the second part is used to carry and indicate the synchronization data.

11. The synchronization method according to claim 10, characterized in that: The first part is carried by direct link control information SCI.

12. The synchronization method according to claim 8, characterized in that: The synchronization level of the first terminal includes at least one of the following: A first synchronization level, wherein the first synchronization level indicates that a synchronization source of the first terminal is a Global Navigation Satellite System GNSS signal; The n+1th synchronization level, wherein the n+1th synchronization level indicates that the synchronization source of the first terminal is a terminal of the nth synchronization level; wherein n≥1, and n is a positive integer.

13. The synchronization method according to claim 8, characterized in that: The calculating, according to the second timing offset value, the first timing adjustment value, the second timing adjustment value, and the third timing offset value, an actual timing deviation between the second terminal and the first terminal includes: The actual timing deviation between the two first terminals is calculated according to the following formula: Rt xy (Ta xy -Are yx -Td x +Td y +Δt yx −Δt xy ) / 2; Where x is the second terminal, y is the first terminal, Rt xy is the actual timing deviation between the first terminal and the second terminal; Ta yx is the second timing offset value; Ta xy is the third timing offset value; Td x is the second timing adjustment value; Td y is the first timing adjustment value; Δt yx A timing measurement error determined for the first terminal; Δt xy A timing measurement error is determined for the second terminal.

14. The synchronization method according to claim 8, characterized in that: Also includes: receiving a second synchronization signaling sent by the terminal, where the second synchronization signaling is on a direct link broadcast channel PSBCH sent through a reserved subframe; Among them, the second synchronization signaling is used to indicate the synchronization level of the first terminal; the second synchronization signaling includes: indication information of whether the first terminal device is within the coverage of the GNSS and the direct link synchronization signal index.

15. The synchronization method according to claim 14, characterized in that: The correspondence between the synchronization level, the indication information, and the through link synchronization signal index includes at least one of the following: When the indication information is 1 and the through link synchronization signal index is 0, it indicates that the synchronization level of the first terminal device is the first synchronization level; When the indication information is 0 and the direct link synchronization signal index is 0, it indicates that the synchronization level of the first terminal device is not the first synchronization level.

16. A synchronization device, characterized in that: Applied to the first terminal, comprising: A first sending module is configured to send a pilot signal and a first synchronization signaling, where the first synchronization signaling is used for other terminals to synchronize with the first terminal; wherein the first synchronization signaling is used to indicate the following synchronization data: a synchronization level of the first terminal; a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling; a first timing adjustment value, where the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling; The second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal.

17. A synchronization device, characterized in that: Applied to the second terminal, including: A first receiving module, configured to receive a pilot signal and a first synchronization signaling sent by a first terminal; A first synchronization processing module, configured to synchronize with the first terminal according to the first synchronization signaling when the synchronization level of the first terminal is higher than the synchronization level of the second terminal; The first synchronization signaling is used to indicate the following synchronization data: a synchronization level of the first terminal; a first timing offset value of a synchronization source, wherein the first timing offset value is a timing offset of a synchronization source of the first terminal relative to a reference time when sending the first synchronization signaling; a first timing adjustment value, where the first timing adjustment value is an adjustment amount when the first terminal is synchronized with a synchronization source when sending the first synchronization signaling; a second timing offset value of the first terminal, where the second timing offset value is a timing offset between the first terminal and the second terminal; The first synchronization processing module is specifically used to: By receiving the first synchronization signaling sent by the first terminal, the second terminal determines a third timing offset value relative to the first terminal; determining a second timing adjustment value of the second terminal when receiving the first synchronization signaling; Calculate an actual timing deviation between the second terminal and the first terminal according to the second timing offset value, the first timing adjustment value, the second timing adjustment value, and the third timing offset value; The second terminal is synchronized with the first terminal according to the actual timing deviation.

18. A terminal, the terminal being a first terminal, comprising: A transceiver, a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the steps of the synchronization method according to any one of claims 1 to 7.

19. A terminal, the terminal being a second terminal, comprising: A transceiver, a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the steps of the synchronization method according to any one of claims 8 to 15.

20. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the synchronization method according to any one of claims 1 to 15 are implemented.

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