WO2022188693A1 - 一种同步方法及设备 - Google Patents

一种同步方法及设备 Download PDF

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Publication number
WO2022188693A1
WO2022188693A1 PCT/CN2022/079120 CN2022079120W WO2022188693A1 WO 2022188693 A1 WO2022188693 A1 WO 2022188693A1 CN 2022079120 W CN2022079120 W CN 2022079120W WO 2022188693 A1 WO2022188693 A1 WO 2022188693A1
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WIPO (PCT)
Prior art keywords
synchronization
terminal
type
synchronization signal
synchronized
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PCT/CN2022/079120
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English (en)
French (fr)
Inventor
刘云
才宇
薛丽霞
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华为技术有限公司
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Publication of WO2022188693A1 publication Critical patent/WO2022188693A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
    • H04W4/30—Services specially adapted for particular environments, situations or purposes
    • H04W4/40—Services specially adapted for particular environments, situations or purposes for vehicles, e.g. vehicle-to-pedestrians [V2P]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H04W24/02—Arrangements for optimising operational condition
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
    • H04W4/70—Services for machine-to-machine communication [M2M] or machine type communication [MTC]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/02—Power saving arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/02—Power saving arrangements
    • H04W52/0209—Power saving arrangements in terminal devices
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/001—Synchronization between nodes
    • H04W56/0015—Synchronization between nodes one node acting as a reference for the others

Definitions

  • the present application relates to the field of communication technologies, and in particular, to a synchronization method and device.
  • the fourth generation ( 4th generation, 4G) communication system Long Term Evolution (Long Term Evolution) , LTE) system
  • fifth generation ( 5th generation, 5G) communication system ie new radio (new radio, NR) system
  • This communication method is called sidelink communication, and the connection established between the two terminals is a direct link.
  • V2X vehicle to everything
  • V2X is mainly used to realize the communication between vehicles, roadside infrastructure (infrastructure), pedestrians (pedestrian), network (network), etc. communication.
  • 3GPP introduced support for V2X services in the LTE system in order to extend the 3GPP platform to the automotive industry; during release16, the related design of NR V2X was studied.
  • the primary process is synchronization.
  • terminals need to be synchronized according to a preset synchronization method: for example, synchronization based on a global navigation satellite system (GNSS), or synchronization based on a base station (gNB/eNB).
  • GNSS global navigation satellite system
  • gNB/eNB base station
  • Each synchronization method also specifies the synchronization priority of different types of equipment. For example, in the GNSS-based synchronization method, the GNSS synchronization priority is the highest; in the base station synchronization method, the base station synchronization priority is the highest.
  • a terminal that needs to be synchronized (hereinafter referred to as a terminal to be synchronized) configured in a certain synchronization mode is preferentially synchronized with a device with a high synchronization priority in the synchronization mode.
  • the terminal to be synchronized can be pre-determined; while the resources used by other types of devices (generally, terminals that are directly or indirectly synchronized to the GNSS or base station) are determined by their own If the configuration is determined, the terminal to be synchronized cannot be determined in advance. Therefore, the terminal to be synchronized can search for the synchronization signal of the GNSS or the base station on the predetermined fixed resources, but if the terminal to be synchronized does not search for the synchronization signal of the GNSS or the base station, the terminal to be synchronized must be synchronized to a synchronization priority lower than that of the GNSS. or other types of equipment at the base station.
  • the terminal to be synchronized needs to be synchronized on all subframes in the frame. All search (full search, also known as exhaustive search), so that all synchronization signals can be searched.
  • the terminal to be synchronized in the sidelink communication system needs to search for the synchronization signal on all subframes in the frame, and also needs to compare the reliability of the searched synchronization signal, which will cause high power consumption of the terminal to be synchronized. consumption.
  • the present application provides a synchronization method and device, which are used to reduce the opportunity or time for a terminal to be synchronized to search for a synchronization signal, so as to reduce the power consumption caused by the search for a synchronization signal.
  • an embodiment of the present application provides a synchronization method, which can be applied to a terminal to be synchronized in a sidelink communication system, and the method includes the following steps:
  • the to-be-synchronized terminal determines target synchronization priority configuration information, where the target synchronization priority configuration information is used to indicate synchronization priorities of different types of devices; then the to-be-synchronized terminal performs synchronization according to the target synchronization priority configuration information.
  • the target synchronization priority configuration information the synchronization priority of the first type of equipment is the highest, the synchronization priority of the second type of equipment is higher than or equal to the synchronization priority of the third type of equipment, the third type of equipment is a terminal synchronized to the first type of equipment; the first type of equipment is a GNSS, and the second type of equipment is a base station; or the first type of equipment is a base station, and the second type of equipment is a GNSS.
  • the terminal to be synchronized can preferentially synchronize to the second type of device when the synchronization signal of the first type of device is not found or when the signal quality of the synchronization signal of the first type of device is found to be lower than the set threshold, so that the terminal to be synchronized can
  • the second type of device is preferred as the synchronization source.
  • the second type of equipment is a base station or GNSS, that is, the resources used by the second type of equipment to send synchronization signals are fixed resources, therefore, if the terminal to be synchronized is not synchronized to the first type of equipment, it is not necessary to search for the first type of equipment.
  • the synchronization signal of the second-class device and when the terminal to be synchronized uses the second-class device as the synchronization source, there is no need to perform all searches. Therefore, compared with the traditional synchronization priority configuration, the method can significantly reduce the opportunity of the terminal to be synchronized to search for the synchronization signal, thereby reducing the power consumption caused by the search for the synchronization signal.
  • the synchronization priority of the first type of device is relative.
  • the specific situation of the relationship can include the following three situations in this design:
  • Case 1 The synchronization priority of the first type of equipment is higher than the synchronization priority of the second type of equipment, and the synchronization priority of the second type of equipment is higher than the synchronization priority of the third type of equipment; namely The synchronization priority of the first type of device > the synchronization priority of the second type of device > the synchronization priority of the third type of device.
  • the terminal to be synchronized can perform synchronization according to the synchronization priority configuration information through the following steps:
  • the synchronization is performed with the device of the second type according to the synchronization signal of the device of the second type;
  • the terminal to be synchronized may perform synchronization according to the synchronization priority configuration information through the following steps:
  • the terminal to be synchronized may perform synchronization according to the synchronization priority configuration information through the following steps:
  • the synchronization is performed with the device of the third type according to the synchronization signal of the device of the third type;
  • the synchronization priority of the second type of equipment is higher than or equal to the synchronization priority of the third type of equipment.
  • the terminal to be synchronized can preferentially synchronize to the second type of equipment when the synchronization signal of the first type of equipment is not searched or the signal quality of the searched for the first type of equipment is lower than the set threshold, so as to be synchronized
  • the terminal may preferentially select the second type of device as the synchronization source.
  • the synchronization priority of the first type device is higher than or equal to the synchronization priority of the second type device, and the synchronization priority of the first type device The priority is higher than the synchronization priority of the third-type device; based on this, the terminal to be synchronized can perform synchronization according to the synchronization priority configuration information through the following steps:
  • the synchronization is performed with the device of the second type according to the synchronization signal of the device of the second type;
  • the synchronization is performed according to the synchronization signal of the third-type device .
  • the synchronization priority of the second type of equipment is higher than or equal to the synchronization priority of the third type of equipment.
  • the terminal to be synchronized can preferentially synchronize to the second type of equipment when the synchronization signal of the first type of equipment is not searched or the signal quality of the searched for the first type of equipment is lower than the set threshold, so as to be synchronized
  • the terminal may preferentially select the second type of device as the synchronization source.
  • the synchronization priority of the second type device may also be determined to be higher than that of the second type device. or equal to the synchronization priority of the current synchronization source of the terminal to be synchronized; and/or determine that the signal quality of the synchronization signal of the second type of device is greater than or equal to a set threshold.
  • the terminal to be synchronized can be synchronized to a device with high synchronization priority and high reliability of the synchronization signal as much as possible, thereby ensuring the accuracy of the time synchronization of the terminal to be synchronized.
  • the terminal to be synchronized will continue to adjust the synchronization source:
  • Case 1 When the synchronization signal of the second type of equipment is not searched, or the signal quality of the searched synchronization signal of the second type of equipment is lower than the set threshold, the the synchronization signal is synchronized with the second type of equipment;
  • Case 2 When the synchronization signal of the first-type device is searched, the synchronization is performed with the first-type device according to the synchronization signal of the first-type device.
  • the terminal to be synchronized can adjust the synchronization source in time according to the real-time change of the synchronization signal of the second type of equipment, so as to ensure that the terminal to be synchronized can be synchronized to a device with high synchronization priority and reliable synchronization signal.
  • the terminal to be synchronized when the terminal to be synchronized detects the synchronization signal of the TDD base station or the synchronization signal of the terminal synchronized to the TDD base station, it indicates that the current application scenario GNSS exists. Therefore, in this design, before determining the target synchronization priority configuration information, the terminal to be synchronized can also perform a search for the synchronization signal of the target terminal.
  • the terminal of the base station, or the target terminal is located within the coverage of the base station in the TDD communication mode; or the synchronization signal of the second type of device is searched.
  • the terminal to be synchronized searches for the synchronization signal of the target terminal, it indicates that GNSS exists in the current application scenario. Therefore, the terminal to be synchronized can use the target synchronization priority configuration information, so that the above method can be implemented.
  • the second type of device is a base station in a TDD communication mode.
  • the terminal to be synchronized may perform synchronization according to the target synchronization priority configuration information through the following steps:
  • the first time range is determined according to the synchronization information of the current synchronization source; wherein, the fourth type device is the synchronization source to the terminal of the third type of device; searching for a synchronization signal within the first time range.
  • the first time range may also be referred to as a search time range, which is a time range in which the terminal to be synchronized performs the search.
  • the first time range is a time range for the terminal to be synchronized to search for synchronization signals of other terminals related to the current synchronization source.
  • the terminal to be synchronized does not search for synchronization signals outside the first time range. Therefore, compared with the traditional full search, this implementation can greatly reduce the time for the terminal to be synchronized to perform all searches, thereby significantly reducing Power consumption of the terminal to be synchronized.
  • the search when the terminal to be synchronized performs the search for the synchronization signal within the first time range, the search may be performed in all time units within the first time range, or The search is performed in part of time units (subframes or time slots) within the first time range, which is not limited in this application.
  • the time domain position of the part of the time unit where the search is performed may be continuous or discrete, which is not limited in this application.
  • the synchronization information of the current synchronization source includes synchronization signal time domain information, and the synchronization signal time domain information is used to indicate a first duration, and the first duration is sent by the current synchronization source.
  • the duration of the sync signal may be determined the first time range according to the time domain information of the synchronization signal.
  • the terminal to be synchronized can determine the first time range according to the first duration of the current synchronization source, so that the first time range can be searched for the current The synchronization signal of other terminals related to the synchronization source.
  • the time domain information of the synchronization signal is specified by a protocol, or configured for the base station to which the terminal to be synchronized is accessed, or configured for the current synchronization source.
  • the duration of the first time range is greater than or equal to the first duration indicated by the time domain information of the synchronization signal.
  • the duration of the first time range is greater than or equal to the first duration indicated by the time domain information of the synchronization signal.
  • the duration of the first time range may be greater than the first duration indicated by the synchronization signal time domain information.
  • the start position of the first time range is located before the first time domain position, or is equal to the first time domain position; and/or, the end position of the first time range is located at After the second time domain position, or equal to the second time domain position;
  • the first time domain position is the time domain position where the terminal to be synchronized searches for the synchronization signal of the current synchronization source; the second time domain position is located after the first time domain position, and is different from the The interval duration between the first time domain positions is equal to the first duration indicated by the time domain information of the synchronization signal.
  • the terminal to be synchronized can determine the time domain position of the first time range according to the searched time domain position and first duration of the synchronization signal of the current synchronization source.
  • the first time range includes some or all of the symbols in the second time range; and/or, the first time range includes some or all of the symbols in the third time range;
  • the second time range is the time range between the start position of the first time range and the first time domain position
  • the third time range is the time range between the second time domain position and the first time domain position The time range between the end positions of the first time range.
  • the terminal to be synchronized when the terminal to be synchronized does not search for the synchronization signals of the third-type device and the fourth-type device within the first time range (and does not search for the synchronization signal of the first-type device either) synchronization signal), the terminal to be synchronized may also search for synchronization signals on all time units within the fourth time range (such as search time period, frame), that is, return to all search, so that the terminal to be synchronized can pass all search, Synchronization is achieved by searching for the synchronization signal of the terminal.
  • the terminal to be synchronized when the terminal to be synchronized does not search for a synchronization signal of any type of device within the first time range, it searches for a synchronization signal on each subframe in the frame.
  • the terminal to be synchronized may search for a synchronization signal in the following manner:
  • the synchronization signal of the first terminal When the synchronization signal of the first terminal is searched, the synchronization signal of at least one target class device is searched; wherein, the sequence of the synchronization signal of the at least one target class device is within the set signal sequence range, and each target class
  • the synchronization priority of the device is higher than or equal to the synchronization priority of the first terminal, and the first terminal belongs to the third type of equipment or the fourth type of equipment.
  • the terminal to be synchronized can be searched and compared without the need for a synchronization priority lower than that of the first terminal.
  • the first terminal is the synchronization signal of other types of terminals, so that the power consumption of the terminal device can be reduced.
  • the terminal to be synchronized may search for a synchronization signal in the following manner:
  • the synchronization signal within the set signal sequence range is searched.
  • the synchronization signal within the set signal sequence range is the synchronization signal of at least one target class device.
  • the synchronization priority of each target class device is higher than or equal to the synchronization priority of the first terminal.
  • the first terminal belongs to the third type of equipment or the fourth type of equipment.
  • the devices of the at least one target class include devices of the first class and devices of the second class.
  • the terminal to be synchronized can be searched and compared without the need for a synchronization priority lower than that of the first terminal.
  • the first terminal is the synchronization signal of other types of terminals, so that the power consumption of the terminal device can be reduced.
  • the signal sequence range of the synchronization signal of the device of each target class can be determined; then according to the range of the synchronization signal of the device of each target class The signal sequence range is compared with the received signal, enabling coherent calculations. Since there is no need to compare synchronization signals of other types of terminals with a synchronization priority lower than that of the first terminal, the power consumption of the terminal device can be reduced.
  • the terminal to be synchronized may determine the target synchronization priority configuration information in the following manner:
  • the terminal to be synchronized receives the indication information (for example, the figure) sent by the network device; wherein, the indication information is used to indicate the synchronization mode; then, the terminal to be synchronized, according to the synchronization mode indicated by the indication information, performs multiple
  • the synchronization priority configuration information is determined in the target synchronization priority configuration information.
  • an embodiment of the present application provides a synchronization method, which can be applied to a terminal to be synchronized in a sidelink communication system, and the method includes the following steps:
  • the terminal to be synchronized determines a first time range according to the synchronization information of the current synchronization source; and searches for a synchronization signal within the first time range.
  • the first time range may also be referred to as a search time range, which is a time range in which the terminal to be synchronized performs the search.
  • the first time range is a time range for the terminal to be synchronized to search for synchronization signals of other terminals related to the current synchronization source.
  • this implementation method can greatly reduce the time for the terminal to be synchronized to perform all searches, thereby significantly reducing Power consumption of the terminal to be synchronized.
  • the search when the terminal to be synchronized performs the search for the synchronization signal within the first time range, the search may be performed in all time units within the first time range, or may be performed in all time units within the first time range.
  • the search is performed in part of time units (subframes or time slots) within the first time range, which is not limited in this application.
  • the time domain position of the part of the time unit where the search is performed may be continuous or discrete, which is not limited in this application.
  • the synchronization information of the current synchronization source includes synchronization signal time domain information, and the synchronization signal time domain information is used to indicate a first duration, and the first duration is sent by the current synchronization source.
  • the duration of the synchronization signal; in this design, the terminal to be synchronized may determine the first time range according to the time domain information of the synchronization signal.
  • the terminal to be synchronized can determine the first time range according to the first duration of the current synchronization source, so that the first time range can be searched for the current The synchronization signal of other terminals related to the synchronization source.
  • the time domain information of the synchronization signal is specified by a protocol, or configured for the base station to which the terminal to be synchronized is accessed, or configured for the current synchronization source.
  • the duration of the first time range is greater than or equal to the first duration indicated by the time domain information of the synchronization signal.
  • the duration of the first time range is greater than or equal to the first duration indicated by the time domain information of the synchronization signal.
  • the duration of the first time range may be greater than the first duration indicated by the synchronization signal time domain information.
  • the start position of the first time range is located before the first time domain position, or is equal to the first time domain position; and/or, the end of the first time range the position is after the second time domain position, or is equal to the second time domain position;
  • the first time domain position is the time domain position where the terminal to be synchronized searches for the synchronization signal of the current synchronization source; the second time domain position is located after the first time domain position, and is different from the The interval duration between the first time domain positions is equal to the first duration indicated by the time domain information of the synchronization signal.
  • the terminal to be synchronized can determine the time domain position of the first time range according to the searched time domain position and first duration of the synchronization signal of the current synchronization source.
  • the first time range includes some or all of the symbols in the second time range; and/or, the first time range includes some or all of the symbols in the third time range;
  • the second time range is the time range between the start position of the first time range and the first time domain position
  • the third time range is the time range between the second time domain position and the first time domain position The time range between the end positions of the first time range.
  • the terminal to be synchronized when the terminal to be synchronized does not search for a synchronization signal of any type of equipment (and also does not search for a synchronization signal of a base station or GNSS) within the first time range, the terminal to be synchronized It is also possible to search for synchronization signals in all time units within the fourth time range (eg, search time period, frame), that is, to return to all search, so that the terminal to be synchronized can search for the synchronization signal of the terminal through all search to achieve synchronization.
  • the fourth time range eg, search time period, frame
  • the terminal to be synchronized may search for a synchronization signal in the following manner:
  • the synchronization signal of the first terminal When the synchronization signal of the first terminal is searched, the synchronization signal of at least one target class device is searched; wherein, the sequence of the synchronization signal of the at least one target class device is within the set signal sequence range, and each target class The synchronization priority of the device is higher than or equal to the synchronization priority of the first terminal.
  • the terminal to be synchronized can be searched and compared without the need for a synchronization priority lower than that of the first terminal.
  • the first terminal is the synchronization signal of other types of terminals, so that the power consumption of the terminal device can be reduced.
  • the terminal to be synchronized may also search for a synchronization signal in the following manner:
  • the synchronization signal within the set signal sequence range is searched.
  • the synchronization signal within the set signal sequence range is the synchronization signal of at least one target class device.
  • the synchronization priority of each target class device is higher than or equal to the synchronization priority of the first terminal.
  • the terminal to be synchronized can be searched and compared without the need for a synchronization priority lower than that of the first terminal.
  • the first terminal is the synchronization signal of other types of terminals, so that the power consumption of the terminal device can be reduced.
  • the signal sequence range of the synchronization signal of the device of each target class can be determined; then according to the range of the synchronization signal of the device of each target class The signal sequence range is compared with the received signal, enabling coherent calculations. Since there is no need to compare synchronization signals of other types of terminals with a synchronization priority lower than that of the first terminal, the power consumption of the terminal device can be reduced.
  • an embodiment of the present application provides a synchronization method, which can be applied to a terminal to be synchronized in a sidelink communication system, and the method includes the following steps:
  • the synchronization signal is searched according to the target synchronization priority configuration information; wherein the target synchronization priority configuration information is used to indicate the synchronization priorities of different types of devices;
  • the synchronization terminal may use any of the following methods to search for synchronization signals according to the target synchronization priority configuration information:
  • Manner 1 When the synchronization signal of the first terminal is searched, the synchronization signal of at least one target class device is searched. Wherein, the sequence of the synchronization signal of the device of the at least one target class is within the set signal sequence range, and the synchronization priority of each target class device is higher than or equal to the synchronization priority of the first terminal;
  • Mode 2 When the synchronization signal of the first terminal is searched, the synchronization signal within the set signal sequence range is searched.
  • the synchronization signal within the set signal sequence range is the synchronization signal of at least one target class device.
  • the synchronization priority of each target class device is higher than or equal to the synchronization priority of the first terminal.
  • the terminal to be synchronized can be searched and compared without the need for a synchronization priority lower than that of the first terminal.
  • the first terminal is the synchronization signal of other types of terminals, so that the power consumption of the terminal device can be reduced.
  • the signal sequence range of the synchronization signal of the device of each target class can be determined; then according to the range of the synchronization signal of the device of each target class The signal sequence range is compared with the received signal, enabling coherent calculations. Since there is no need to compare synchronization signals of other types of terminals with a synchronization priority lower than that of the first terminal, the power consumption of the terminal device can be reduced.
  • an embodiment of the present application provides a terminal, including a unit for performing each step in the above first aspect to the third aspect.
  • an embodiment of the present application provides a terminal, including at least one processing element and at least one storage element, wherein the at least one storage element is used to store programs and data, and the at least one processing element is used to execute the above-mentioned item of the present application.
  • an embodiment of the present application provides a communication apparatus, including a unit for executing the steps of the synchronization method introduced in any embodiment of the present application.
  • an embodiment of the present application provides a communication device, including at least one processing element and at least one storage element, wherein the at least one storage element is used to store programs and data, and the at least one processing element is used to execute any The steps of the synchronization method described in an embodiment.
  • an embodiment of the present application further provides a computer program, which, when the computer program runs on a computer, causes the computer to execute the method provided in any of the foregoing aspects.
  • an embodiment of the present application further provides a computer storage medium, where a computer program is stored in the computer storage medium, and when the computer program is executed by the computer, the computer is made to execute the method provided in any of the foregoing aspects.
  • an embodiment of the present application further provides a chip, where the chip is configured to read a computer program stored in a memory and execute the method provided in any one of the foregoing aspects.
  • an embodiment of the present application further provides a chip system, where the chip system includes a processor for supporting a computer device to implement the method provided in any one of the foregoing aspects.
  • the chip system further includes a memory for storing necessary programs and data of the computer device.
  • the system-on-chip may consist of chips, or may include chips and other discrete devices.
  • 1A is a schematic diagram of a traditional synchronization priority configuration
  • 1B is a schematic diagram of a traditional synchronization priority configuration
  • 1C is a schematic diagram of a traditional synchronization priority configuration
  • FIG. 2 is a schematic diagram of an application scenario provided by an embodiment of the present application.
  • FIG. 3 is a flowchart of a synchronization method provided by an embodiment of the present application.
  • 5A is a schematic diagram of synchronization priority configuration information provided by an embodiment of the present application.
  • 5B is a schematic diagram of synchronization priority configuration information provided by an embodiment of the present application.
  • 5C is a schematic diagram of synchronization priority configuration information provided by an embodiment of the present application.
  • 5D is a schematic diagram of synchronization priority configuration information provided by an embodiment of the present application.
  • FIG. 5E is a schematic diagram of synchronization priority configuration information provided by an embodiment of the present application.
  • 5F is a schematic diagram of synchronization priority configuration information provided by an embodiment of the present application.
  • 5G is a schematic diagram of synchronization priority configuration information provided by an embodiment of the present application.
  • 5H is a schematic diagram of synchronization priority configuration information provided by an embodiment of the present application.
  • 5I is a schematic diagram of synchronization priority configuration information provided by an embodiment of the present application.
  • FIG. 6 is a schematic diagram of an example of a first time range provided by an embodiment of the present application.
  • FIG. 7 is a structural diagram of a terminal according to an embodiment of the present application.
  • FIG. 8 is a structural diagram of another terminal according to an embodiment of the present application.
  • the present application provides a communication method and device, which are used to reduce the opportunity or time for a terminal to be synchronized to search for a synchronization signal, so as to reduce the power consumption caused by the search for a synchronization signal.
  • the method and the device are based on the same technical concept. Since the principles of the method and the device for solving problems are similar, the implementation of the device and the method can be referred to each other, and repeated descriptions will not be repeated.
  • a base station is a device that connects a terminal to a wireless network in a mobile communication system.
  • a base station may also be called a radio access network (radio access network, RAN) node (or device), a network device, and the like.
  • RAN radio access network
  • base stations generation Node B (gNB), evolved Node B (evolved Node B, eNB), transmission reception point (TRP), radio network controller (radio network) controller, RNC), Node B (Node B, NB), access point (access point, AP), base station controller (base station controller, BSC), base transceiver station (base transceiver station, BTS), home base station (such as , home evolved NodeB, or home Node B, HNB), or base band unit (BBU), micro base station, macro base station, etc. in heterogeneous network scenarios.
  • gNB generation Node B
  • eNB evolved Node B
  • TRP transmission reception point
  • RNC radio network controller
  • Node B Node B
  • AP access point
  • base station controller base station controller
  • BTS base transceiver station
  • home base station such as , home evolved NodeB, or home Node B, HNB
  • BBU base band unit
  • the base station may include: a base band unit (base band unit, BBU) and a remote radio unit (remote radio unit, RRU).
  • BBU base band unit
  • RRU remote radio unit
  • a base station may include a baseband pool (BBU pool) and an RRU.
  • BBU pool baseband pool
  • the base station may include a centralized unit (centralized unit, CU) node and a distributed unit (distributed unit, DU) node.
  • CU centralized unit
  • DU distributed unit
  • This structure separates the protocol layers of the eNB in the long term evolution (LTE) system. The functions of some protocol layers are centrally controlled by the CU, and the remaining part or all of the functions of the protocol layers are distributed in the DU, which is controlled by the CU. Centralized control of DU.
  • LTE long term evolution
  • a terminal is a device that provides voice and/or data connectivity to a user.
  • a terminal may also be called a terminal device, a user equipment (UE), a mobile station (mobile station, MS), a mobile terminal (mobile terminal, MT), and the like.
  • UE user equipment
  • MS mobile station
  • MT mobile terminal
  • the terminal may be a handheld device with a wireless connection function, various in-vehicle devices, a roadside unit, or the like.
  • some examples of terminals are: mobile phone (mobile phone), tablet computer, notebook computer, PDA, mobile internet device (MID), smart point of sale (POS), wearable device, virtual Virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self-driving, remote medical surgery wireless terminals, wireless terminals in smart grid, wireless terminals in transportation safety, wireless terminals in smart city, wireless terminals in smart home, various types of wireless terminals Smart meters (smart water meter, smart electricity meter, smart gas meter), eLTE-DSA UE, equipment with integrated access and backhaul (IAB) capability, on-board electronic control unit (ECU), etc. , vehicle computer, vehicle cruise system, telematics box (T-BOX), vehicle communication module, vehicle user equipment (vehicle UE, VUE), etc.
  • T-BOX telematic
  • GNSS refers to all satellite navigation systems, including global, regional and enhanced various satellite navigation systems.
  • the GNSS may include but is not limited to: global positioning system (global positioning system, GPS), global navigation satellite system (global navigation satellite system, GLONASS), Beidou navigation satellite system (beidou navigation satellite system, BDS), Galileo satellite navigation system (Galileo) and so on.
  • GNSS equipment may be referred to as GNSS equipment or GNSS device for short, and generally includes GNSS satellites, ground stations, and the like.
  • GNSS may be used to refer to a GNSS device or a GNSS device, or the like.
  • a device that is, a communication device, is a device with a communication function in a communication system, and in the embodiments of the present application generally refers to a device capable of serving as a synchronization source of a terminal and capable of sending a synchronization signal.
  • the devices may include, but are not limited to, the following types: base stations, GNSS, terminals, and the like.
  • the terminals can be further subdivided into the following types:
  • a terminal that is directly synchronized to the base station may be referred to as the first type of terminal, that is, a terminal that is synchronized to the base station, or a terminal that uses the base station as a synchronization source.
  • the first type of terminal usually, a terminal within the coverage of a base station (in coverage, IC) will generally be directly synchronized to the base station using the base station as a synchronization source. Therefore, the first type of terminal may also be called an IC UE.
  • synchronization to the base station can also be understood as: synchronization to a cell under the base station, synchronization to a cell, and so on. The cell is within the coverage of the base station.
  • the terminal that is indirectly synchronized to the base station can be referred to as the second type of terminal, that is, the terminal that is synchronized to the first type of terminal, or the terminal that uses the first type of terminal as the synchronization source, and can also be recorded as sync with IC UE.
  • the terminal that is directly synchronized to the GNSS can be referred to as the third type of terminal, that is, the terminal that is synchronized to the GNSS, or the terminal that uses the GNSS as the synchronization source, and can also be recorded as the GNSS UE.
  • the synchronization source of the third type of terminal is GNSS, which can be specifically GNSS equipment, can be GNSS satellites or ground stations, etc., which is not limited in this application.
  • the terminal that is indirectly synchronized to the GNSS can be referred to as the fourth type of terminal, that is, the terminal that is synchronized to the third type of terminal, or the terminal that uses the third type of terminal as the synchronization source, can also be recorded as sync with GNSS UE.
  • the first type of terminals and the second type of terminals may be collectively referred to as base station-related terminals, and the third type of terminals and the fourth type of terminals may be collectively referred to as GNSS-related terminals.
  • the synchronization priority of the device can be understood as: the priority of the device being synchronized when the device is used as the synchronization source, or the priority of the device as the synchronization source, the terminal uses the device as the priority of the synchronization source, and the terminal uses the device.
  • the synchronization priority of the synchronization signal can be understood as: the priority of the device being synchronized when the device is used as the synchronization source, or the priority of the device as the synchronization source, the terminal uses the device as the priority of the synchronization source, and the terminal uses the device.
  • the synchronization priority of the synchronization signal can be understood as: the priority of the device being synchronized when the device is used as the synchronization source, or the priority of the device as the synchronization source, the terminal uses the device as the priority of the synchronization source, and the terminal uses the device.
  • the synchronization priority of the synchronization signal can be understood as: the priority of the device being synchronized when the device is used as the synchronization
  • the communication mode of the base station also known as the communication mode of the cell managed by the base station, generally includes two types: time-division duplex (TDD) and frequency-division duplex (FDD).
  • TDD time-division duplex
  • FDD frequency-division duplex
  • the TDD communication mode means that the downlink (downlink, DL) and uplink (uplink, UL) of the mobile communication system share the same frequency point, and in order to avoid signal interference between the DL and UL, the mobile communication system adopts DL communication and UL communication are performed at different times.
  • the FDD communication mode means that the DL and UL in the mobile communication system use different frequencies. Since there is no signal interference between DL and UL in the FDD communication mode, the mobile communication system can perform DL communication and UL communication at the same time.
  • TDD base station A base station in a TDD communication mode is referred to as a TDD base station for short.
  • TDD base stations are usually internally configured with GNSS modules to receive GNSS synchronization signals and synchronize to GNSS.
  • a base station in an FDD communication mode is referred to as an FDD base station for short. Since the UL and DL of the FDD base station use different frequency points, even if it cannot accurately achieve network-wide synchronization, it will not affect its communication. Therefore, the FDD base station does not need to configure the GNSS module.
  • the TDD base station or the terminal synchronized to the TDD base station may carry the uplink and downlink time configuration in the synchronization signal. than information or TDD indication.
  • the TDD indication may indicate the uplink and downlink time ratio information in the TDD communication mode; or the TDD indication may indicate that the base station sending the synchronization signal is a TDD base station, and/or the terminal sending the synchronization signal is to synchronize to TDD The terminal of the base station.
  • the uplink and downlink time matching information or the TDD indication may be sent in a broadcast channel bearing a synchronization signal.
  • the terminal can determine that the device sending the synchronization signal is the TDD base station or the terminal synchronized to the TDD base station according to the uplink and downlink time ratio information or TDD indication in the broadcast channel carrying the synchronization signal .
  • a synchronization signal (synchronization signal), a reference signal used to provide a time reference to the device to be synchronized.
  • the synchronization signals sent by different types of devices are different.
  • the synchronization signal can be sent in a broadcast channel (BCH).
  • the synchronization signal sent by the base station is a synchronization signal block (SSB)
  • the synchronization signal sent by the GNSS is generally a GNSS signal, such as a GPS signal. Therefore, after receiving the synchronization signal of the non-SL-SSB, the terminal can judge whether the synchronization signal is sent by the GNSS or the base station by the type of the synchronization signal (whether it is an SSB or a GNSS signal).
  • a synchronization signal sent by a terminal may be called a sidelink synchronization signal (SLSS) or a sidelink-synchronization signal block (SL-SSB).
  • SLSS sidelink synchronization signal
  • SL-SSB sidelink-synchronization signal block
  • the signal sequence of the SL-SSB is within a predetermined signal sequence range, for example, the signal sequence range includes several hundreds of signal sequences.
  • the SL-SSB sent by the third type of terminal is the SL-SSB signal sequence marked with 0;
  • the SL-SSB sent by the terminal is the SL-SSB signal sequence of other labels.
  • SL-SSB consists of sidelink primary synchronization signal (SPSS) and sidelink secondary synchronization signal (SSSS).
  • SPSS sidelink primary synchronization signal
  • SSSS sidelink secondary synchronization signal
  • the terminal may identify that the SL-SSB is sent by the terminal through a sidelink synchronization signal identifier (sidelink synchronization signal identifier, SL-SSID) in the SL-SSB. Therefore, after receiving the SL-SSB, the terminal to be synchronized can identify the terminal sending the SL-SSB by detecting the SL-SSID in the SL-SSB.
  • sidelink synchronization signal identifier sidelink synchronization signal identifier
  • the SL-SSB can be carried in a physical sidelink broadcast channel (physical sidelink broadcast channel, PSBCH) and sent.
  • the SL-SSID can be carried in the PSBCH and sent.
  • the uplink and downlink time matching information or the TDD indication may also be carried in the PSBCH in the SL-SSB.
  • the terminal may transmit at least one SL-SSB within the SL-SSB period.
  • the SL-SSB period may be 160 milliseconds (ms), 80 ms, or the like.
  • the synchronization signal of a certain type of device is not searched for may mean that the synchronization signal of the device of this type is not detected, or the detected signal quality of the synchronization signal of the device of this type is lower than the set threshold.
  • searching for a synchronization signal of a certain type of device may mean that the synchronization signal of this type of device is detected, or the detected signal quality of the synchronization signal of this type of device is greater than or equal to a set threshold.
  • search time period time unit, symbol, which is the time unit.
  • the search time period may be one or more frames (frame), or a set duration, which is not limited in this application.
  • Time unit the unit used to make up the search time period.
  • the time unit may be one or more subframes (subframes), or one or more time slots (slots), or a set duration, which is not limited in this application.
  • Symbol the smallest unit used to form a time unit, also known as a time symbol or a time domain symbol, such as an OFDM symbol.
  • the current synchronization mechanism is first described below.
  • the synchronization mode can be determined by a synchronization priority configuration parameter, and the synchronization priority configuration parameter can be expressed as SL-SyncPriority (used to indicate the synchronization priority order of devices).
  • the SL-SyncPriority of the terminal may be dynamically configured by the base station or configured before the terminal leaves the factory.
  • SL-SyncPriority By setting the value of SL-SyncPriority, it can be indicated that the device with the highest synchronization priority is the base station or GNSS.
  • SL-SyncPriority is configured as base station (gNB/eNB) indication information (for example, 1), it indicates that the base station has the highest synchronization priority, and the terminal is preferentially synchronized to the base station.
  • gNB/eNB base station
  • indication information for example, 1
  • the SL-SyncPriority When the SL-SyncPriority is configured as GNSS indication information (for example, 0), it indicates that the synchronization priority of the GNSS is the highest, and the terminal synchronizes to the GNSS preferentially.
  • whether the base station can serve as the synchronization source can also be indicated by whether the base station configures parameters for the synchronization source. Whether the base station is a synchronization source configuration parameter can be expressed as SL-NbAsSync.
  • SL-NbAsSync by setting the value of SL-NbAsSync, it can indicate whether the base station can be used as a synchronization source.
  • SL-NbAsSync is configured as the first indication information (such as (true), 1, etc.)
  • SL-NbAsSync is configured as the second indication information (for example, false, 0, etc.), it indicates that the base station cannot be used as the synchronization source of the terminal (or the terminal does not support the base station as the synchronization source).
  • the SL-NbAsSync of the terminal can also be dynamically configured for the base station, or pre-configured before the terminal leaves the factory.
  • Pi represents the synchronization priority, the lower the value of i, the higher the synchronization priority, and the higher the value of i, the lower the synchronization priority.
  • the synchronization priority of P0 is the highest, the synchronization priority of P1 is lower than that of P0, but higher than that of P2, and so on.
  • the SL-SyncPriority is configured as base station (gNB/eNB) indication information, and the terminal adopts the synchronization method of preferentially synchronizing to the base station.
  • the synchronization priorities of the various devices are as shown in FIG. 1A .
  • the synchronization priority of the base station is the highest, that is, P0: base station.
  • the terminal to be synchronized preferentially considers the base station as the synchronization source.
  • the terminal to be synchronized When the terminal to be synchronized does not search for the synchronization signal of the base station, or the signal quality of the searched base station synchronization signal is lower than the set threshold, the terminal to be synchronized will then consider the first type of terminal related to the base station (ie P1: directly synchronized to The terminal of the base station, IC UE) acts as the synchronization source.
  • P1 directly synchronized to The terminal of the base station, IC UE
  • the terminal to be synchronized When the terminal to be synchronized does not search for the synchronization signal of the terminal of the first type, or the signal command of the searched terminal of the synchronization signal of the terminal of the first type is lower than the set threshold, the terminal to be synchronized will then consider the terminal of the second type related to the base station (i.e. P2: The terminal that is indirectly synchronized to the base station, sync with IC UE) as the synchronization source.
  • P2 The terminal that is indirectly synchronized to the base station, sync with IC UE
  • the terminal to be synchronized When the terminal to be synchronized does not search for the synchronization signal of the second type of terminal, or the signal quality of the searched synchronization signal of the second type of terminal is lower than the set threshold, then the terminal to be synchronized considers GNSS (ie P3: GNSS) as the synchronization source.
  • GNSS ie P3: GNSS
  • the terminal to be synchronized When the terminal to be synchronized does not search for the GNSS synchronization signal, or the signal quality of the searched GNSS synchronization signal is lower than the set threshold, then the terminal to be synchronized considers the third type of terminal related to GNSS (ie P4: directly synchronized to GNSS terminal, GNSS UE) as synchronization source.
  • P4 directly synchronized to GNSS terminal, GNSS UE
  • the terminal to be synchronized When the terminal to be synchronized does not search for the synchronization signal of the third type of terminal, or the signal quality of the searched synchronization signal of the third type of terminal is lower than the set threshold, then the terminal to be synchronized will consider the fourth type of terminal related to GNSS ( That is, P5: the terminal that is indirectly synchronized to the GNSS, sync with GNSS UE) as the synchronization source.
  • P5 the terminal that is indirectly synchronized to the GNSS, sync with GNSS UE
  • P6 other terminals, indicating that when the terminal to be synchronized does not search for the synchronization signal of the base station, the synchronization signal of the terminal related to the base station, the synchronization signal of the GNSS, and the synchronization signal of the terminal related to the GNSS, then the terminal to be synchronized sends the synchronization signal by itself signal, as a synchronization source for other devices.
  • SL-SyncPriority is configured as GNSS indication information
  • SL-NbAsSync is configured as first indication information (eg true).
  • the terminal adopts the synchronization method of preferentially synchronizing to the GNSS, and the base station can be used as the synchronization source.
  • the synchronization priorities of various devices are as shown in FIG. 1B .
  • the synchronization priority of GNSS is the highest, that is, P0: GNSS.
  • the terminal to be synchronized preferentially considers GNSS as the synchronization source.
  • the terminal to be synchronized will consider the third type of GNSS-related terminal (P1: directly synchronized to GNSS terminal, GNSS UE), the fourth type of terminal related to GNSS (P2: terminal that is indirectly synchronized to GNSS, sync with GNSS UE), base station, and the first type of terminal related to the base station (P4: directly synchronized to the base station terminal, IC UE), and the second type of terminal related to the base station (P5: terminal that is indirectly synchronized to the base station, sync with IC UE) as the synchronization source.
  • P1 directly synchronized to GNSS terminal, GNSS UE
  • P2 terminal that is indirectly synchronized to GNSS, sync with GNSS UE
  • base station and the first type of terminal related to the base station
  • P4 directly synchronized to the base station terminal, IC UE
  • P5 terminal that is indirectly synchronized to the base station, sync with IC UE
  • the terminal to be synchronized does not search for the synchronization signal of GNSS, the synchronization signal of the terminal related to GNSS, the synchronization signal of the base station, and the synchronization signal of the terminal related to the base station, then the terminal to be synchronized sends the synchronization signal by itself as other synchronization signals.
  • the sync source for the device is not searched for the synchronization signal of GNSS, the synchronization signal of the base station, and the synchronization signal of the terminal related to the base station.
  • SL-SyncPriority is configured as GNSS indication information
  • SL-NbAsSync is configured as second indication information (for example, false).
  • the terminal adopts the synchronization method of preferentially synchronizing to the GNSS, and the base station cannot be used as the synchronization source.
  • the synchronization priorities of the various devices are shown in Figure 1C.
  • the synchronization priority of GNSS is the highest, namely P0: GNSS.
  • the terminal to be synchronized preferentially considers GNSS as the synchronization source.
  • the terminal to be synchronized considers the third type of terminal related to GNSS (P1: terminal directly synchronized to GNSS , GNSS UE), and the fourth type of terminal related to GNSS (P2: terminal that is indirectly synchronized to GNSS, sync with GNSS UE) as the synchronization source.
  • P1 terminal directly synchronized to GNSS
  • P2 terminal that is indirectly synchronized to GNSS, sync with GNSS UE
  • the terminal to be synchronized When the terminal to be synchronized does not search for the synchronization signal of the GNSS or the synchronization signal of the terminal related to the GNSS, the terminal to be synchronized sends the synchronization signal by itself as the synchronization source of other devices.
  • the terminal to be synchronized can be determined in advance.
  • the resources used by the GNSS-related terminal or the base station-related terminal are determined by the configuration of the terminal itself, and the terminal to be synchronized cannot be predetermined. Therefore, in the configuration process in the above three cases, the terminal to be synchronized can search for the synchronization signal of the GNSS or the base station on the predetermined fixed resources, but if the terminal to be synchronized does not search for the synchronization signal of the GNSS or the base station, then the terminal to be synchronized can search for the synchronization signal of the GNSS or the base station.
  • the terminal needs to synchronize to a terminal whose synchronization priority is lower than that of the GNSS or base station.
  • the terminal to be synchronized needs to perform a full search (full search, also known as exhaustive search) on all subframes in the frame, so that the synchronization signals of as many terminals as possible can be searched.
  • full search also known as exhaustive search
  • the terminal to be synchronized in the sidelink communication system needs to search for the synchronization signal on all subframes in the frame, and also needs to compare the reliability of the searched synchronization signal, which will cause high power consumption of the terminal to be synchronized. consumption.
  • an embodiment of the present application provides a synchronization method. With this method, the opportunity or time for the terminal to be synchronized to search for the synchronization signal can be reduced, thereby reducing the power consumption caused by the search for the synchronization signal.
  • FIG. 2 shows a schematic diagram of an application scenario to which the synchronization method provided by the embodiment of the present application is applicable.
  • the application scenario includes a mobile communication system and GNSS.
  • a base station and at least one terminal device are included.
  • a base station is an entity that can receive and transmit wireless signals on the network side, and is responsible for providing wireless access-related services for terminals in the cells it manages, implementing physical layer functions, resource scheduling and wireless resource management, and quality of service (Quality of Service). , QoS) management, wireless access control and mobility management functions.
  • a terminal in a mobile communication system needs to access the network through the base station.
  • GNSS equipment such as GNSS satellites and ground stations, and at least one terminal (for example, terminal c and terminal d in FIG. 2 ) are included.
  • a GNSS device similar in function to a base station in a mobile communication system, is responsible for providing services related to wireless access for terminals within its coverage, which will not be repeated here.
  • a terminal in the GNSS needs to access the network through the GNSS device.
  • the mobile communication system and GNSS support sidelink communication technology.
  • the sidelink communication technology is a near-field communication technology that enables direct connection between terminals, also known as proximity services (Proximity services, ProSe) communication technology, or D2D communication technology.
  • ProSe proximity services
  • D2D communication technology a plurality of terminals that are geographically close together and support sidelink communication may form a sidelink communication system (also referred to as a sidelink communication subsystem, a sidelink system, etc.).
  • sidelink communication can be performed between two terminals through a direct link.
  • the terminal a and the terminal b in the mobile communication system can form a sidelink communication system
  • the terminal c and the terminal d in the GNSS can also form a sidelink communication system.
  • the primary process of the terminal accessing the network is synchronization.
  • base stations, GNSS, and terminals can broadcast synchronization signals to provide reference time to other devices.
  • the base station provides synchronization signals.
  • the terminal that is directly synchronized to the base station, or the terminal that uses the base station as the synchronization source, is referred to as the first type of terminal, IC UE, such as terminal a in the figure.
  • the terminal that is indirectly synchronized to the base station, or the terminal that is directly synchronized to the base station as the synchronization source, is referred to as the second type of terminal, sync with IC UE, such as terminal b in the figure.
  • GNSS which provides synchronization signals.
  • the terminal that is directly synchronized to the GNSS, or the terminal that uses the GNSS as the synchronization source, is referred to as the third type of terminal, GNSS UE, such as terminal c in the figure.
  • the terminal that is indirectly synchronized to the base station, or the terminal that is directly synchronized to the GNSS as the synchronization source, is referred to as the fourth type of terminal, sync with GNSS UE, such as terminal d in the figure.
  • the terminal that is directly synchronized to the base station (the first type of terminal) and the terminal that is indirectly synchronized to the base station (the second type of terminal) can also be collectively referred to as the terminal related to the base station; the terminal that is directly synchronized to the GNSS (the third type of terminal), The terminals that are indirectly synchronized to the GNSS (the fourth type of terminals) may also be collectively referred to as GNSS-related terminals.
  • the above six types of devices do not limit the types of devices that actually exist in the application scenario. In an actual application scenario, there may be the above six types of devices, or there may be some types of devices, which are not limited in this embodiment of the present application.
  • each terminal in the above application system needs to continuously search for synchronization signals to continuously perform synchronization.
  • the terminal since the terminal is mobile and the signal quality of the synchronization signal is affected by various factors, the synchronization source of the terminal will change.
  • the base station when it moves to or near the coverage of the base station, the base station may be used as the synchronization source, or the first type terminal or the second type terminal may be used as the synchronization source;
  • GNSS may be used as the synchronization source, or the third or fourth terminal may be used as the synchronization source.
  • the corresponding synchronization priority can be configured according to the configuration.
  • information synchronization priorities of different types of devices, such as shown in FIG. 1A-FIG. 1C ), perform the corresponding synchronization configuration process, the specific process can refer to the above description of the configuration process in different situations, and will not be repeated here.
  • the application scenario shown in FIG. 2 is used as an example, and does not constitute a limitation on the scenarios to which the methods provided in the embodiments of the present application are applicable.
  • the embodiments of the present application do not limit the standards of the mobile communication system and the GNSS.
  • the mobile communication system may be a fifth generation (The 5th Generation, 5G) communication system, a Long Term Evolution (Long Term Evolution, LTE) communication system, a future new generation communication system, or an evolved communication system, etc.
  • 5G Fifth Generation
  • LTE Long Term Evolution
  • LTE Long Term Evolution
  • future new generation communication system or an evolved communication system, etc.
  • the embodiments of this application do not be limited.
  • the synchronization priority configuration information of the terminal e refers to FIG. 1A .
  • the terminal e will continue to search for the synchronization signal of the base station on the set resources broadcast by the base station, so as to preferentially synchronize to the base station; when the terminal e does not search for the synchronization signal of the base station, or the signal quality of the searched base station synchronization signal is lower than the set threshold.
  • terminal e searches for the synchronization signal of terminal b through all searches; when terminal e determines that the signal quality of the synchronization signal of terminal b is greater than or equal to the set threshold, terminal e synchronizes to terminal b and uses terminal b as the current synchronization source.
  • terminal e In order to ensure that terminal e can continuously synchronize to the terminal with the highest signal quality and higher priority, terminal e needs to perform all searches on all subframes in the frame, so that the synchronization signal of the first type of terminal (for example, terminal a) can be searched for , so that it can sync to a device with a higher sync priority.
  • the synchronization signal of the first type of terminal for example, terminal a
  • the terminal e may perform all the above search processes in parallel, as well as the process of searching for the synchronization signal of the base station. The two processes do not conflict.
  • the synchronization configuration process when the synchronization priority configuration parameter (SL-SyncPriority) of the terminal e is the GNSS indication information is similar to the above process and can be referred to each other.
  • an embodiment of the present application provides a synchronization method.
  • the method can be applied to the terminals to be synchronized (for example, terminal a-terminal e) supporting sidelink communication in the application scenario shown in FIG. 2 , and the steps of the method will be described in detail below with reference to the flowchart shown in FIG. 3 .
  • the terminal to be synchronized determines target synchronization priority configuration information, where the target synchronization priority configuration information is used to indicate synchronization priorities of different types of devices.
  • the terminal to be synchronized may determine the target synchronization priority according to the synchronization priority configuration parameter (SL-SyncPriority) and the specific configuration of whether the base station is the synchronization source configuration parameter (SL-NbAsSync). configuration information.
  • SL-SyncPriority the synchronization priority configuration parameter
  • SL-NbAsSync the specific configuration of whether the base station is the synchronization source configuration parameter
  • the base station when SL-SyncPriority is configured as base station indication information, in the target synchronization priority configuration information, the base station has the highest synchronization priority, and the GNSS synchronization priority is higher than or equal to the first type of terminal (terminals synchronized to the base station, The synchronization priority of the terminal that is directly synchronized to the base station).
  • SL-SyncPriority is configured as GNSS indication information
  • SL-NbAsSync is configured as first indication information (for example, yes)
  • GNSS synchronization priority is the highest
  • base station synchronization priority The level is higher than or equal to the synchronization priority of the third type of terminals (terminals synchronized to GNSS, terminals directly synchronized to GNSS).
  • the synchronization priority configuration parameter (SL-SyncPriority) and whether the base station is a synchronization source configuration parameter (SL-NbAsSync) can be used by the network device when the terminal to be synchronized accesses the network device. configured, or pre-configured before leaving the factory for the terminal to be synchronized.
  • the network device may be a base station or a GNSS accessed by a terminal to be synchronized.
  • the target synchronization priority configuration information is configured by the network when the terminal to be synchronized accesses the network device, or preconfigured before the terminal to be synchronized leaves the factory.
  • the terminal device to be synchronized receives indication information sent by the network device, where the indication information is used to indicate the synchronization mode; the terminal device to be synchronized, according to the synchronization mode indicated by the indication information, is stored in the stored
  • the target synchronization priority configuration information is determined from a plurality of synchronization priority configuration information.
  • the indication information may include a synchronization priority configuration parameter (SL-SyncPriority), and whether the base station is a synchronization source configuration parameter (SL-NbAsSync); or the indication information indicates a synchronization method in other ways, and this application does not This is not limited.
  • SL-SyncPriority a synchronization priority configuration parameter
  • SL-NbAsSync a synchronization source configuration parameter
  • the multiple synchronization priority configuration information stored by the terminal device to be synchronized may be configured by the network device, or preconfigured before the terminal to be synchronized leaves the factory, which is not limited in this application.
  • the synchronization priority of the first type of equipment is the highest, the synchronization priority of the second type of equipment is higher than or equal to the synchronization priority of the third type of equipment, the
  • the third type of equipment is a terminal that synchronizes to the first type of equipment; the first type of equipment is GNSS, and the second type of equipment is a base station; or the first type of equipment is a base station, and the second type of equipment is GNSS.
  • the device types represented by the first type of equipment to the third type of equipment are also different.
  • the first embodiment when the SL-SyncPriority of the terminal to be synchronized is configured as GNSS indication information, and SL-NbAsSync is configured as the first indication information, the first type of equipment is GNSS, the second type of equipment is a base station, and the third type of equipment is It is the third type of terminal (that is, the terminal that is directly synchronized to the GNSS, GNSS UE).
  • the second embodiment when SL-SyncPriority is configured as base station indication information, the first type of equipment is the base station, the second type of equipment is the GNSS, and the third type of equipment is the first type of terminal (that is, the terminal directly synchronized to the base station, IC UE ).
  • the terminal to be synchronized performs synchronization according to the target synchronization priority configuration information. That is, the terminal to be synchronized performs synchronization according to the synchronization priorities of different types of devices in the target synchronization priority configuration information.
  • the terminal to be synchronized can perform S302 through the following steps:
  • the synchronization is performed with the device of the second type according to the synchronization signal of the device of the second type;
  • the synchronization is performed according to the synchronization signal of the third-type device .
  • the second embodiment according to the synchronization priority configuration information, the synchronization priority of the first type of equipment, the synchronization priority of the second type of equipment, and the synchronization priority of the third type of equipment.
  • the specific situation includes the following three situations in this embodiment:
  • Case 1 The synchronization priority of the first type of device is higher than the synchronization priority of the second type of device, and the synchronization priority of the second type of device is higher than the synchronization priority of the third type of device. That is, the synchronization priority of the first type of device>the synchronization priority of the second device>the synchronization priority of the third type of device.
  • P0 the first type of equipment
  • P1 the second type of equipment
  • P2 the third type of equipment
  • the terminal to be synchronized may perform S302 through the following steps:
  • the synchronization is performed with the device of the second type according to the synchronization signal of the device of the second type;
  • P0 the first type of equipment, the second type of equipment
  • P1 the third type of equipment...
  • the terminal to be synchronized may perform S302 through the following steps:
  • P0 the first type of equipment
  • P1 the second type of equipment
  • the third type of equipment the third type of equipment
  • the terminal to be synchronized may perform S302 through the following steps:
  • the synchronization is performed with the device of the third type according to the synchronization signal of the device of the third type;
  • the synchronization priority of the second type of device is higher than or equal to the synchronization priority of the third type of device.
  • the terminal to be synchronized can preferentially synchronize to the second type of device when the synchronization signal of the first type of device is not found or when the signal quality of the synchronization signal of the first type of device is found to be lower than the set threshold, so that the terminal to be synchronized can
  • the second type of device is preferred as the synchronization source.
  • the second type of equipment is a base station or GNSS, that is, the resources used by the second type of equipment to send synchronization signals are fixed resources, therefore, if the terminal to be synchronized is not synchronized to the first type of equipment, it is not necessary to search for the first type of equipment.
  • the synchronization signal of the second-class device and when the terminal to be synchronized uses the second-class device as the synchronization source, there is no need to perform all searches. Therefore, compared with the traditional synchronization priority configuration, this method can significantly reduce the probability that the terminal to be synchronized performs all searches, that is, reduces the chance of the terminal to be synchronized searching for synchronization signals, thereby reducing power consumption caused by searching for synchronization signals.
  • the following steps may also be performed:
  • the terminal to be synchronized can be synchronized to a device with a high synchronization priority and high reliability of the synchronization signal as much as possible, thereby ensuring the accuracy of the time synchronization of the terminal to be synchronized.
  • the to-be-synchronized terminal After the terminal to be synchronized is synchronized with the second type of device according to the synchronization signal of the second type of device, if the following conditions occur, the to-be-synchronized terminal Continue to adjust the sync source:
  • Case 1 When the synchronization signal of the second type of equipment is not searched, or the signal quality of the searched synchronization signal of the second type of equipment is lower than the set threshold, the terminal to be synchronized no longer The synchronization signal of the second type of device is synchronized with the second type of device.
  • Case 2 When the synchronization signal of the first type of device is searched, the terminal to be synchronized synchronizes with the first type of device according to the synchronization signal of the first type of device.
  • the terminal to be synchronized can adjust the synchronization source in time according to the real-time change of the synchronization signal of the second type of equipment, so as to ensure that the terminal to be synchronized can be synchronized to a device with high synchronization priority and reliable synchronization signal.
  • the base station in the TDD communication mode is usually configured with a GNSS module internally to synchronize to the GNSS. That is, the synchronization source of the TDD base station is GNSS, and the time of the TDD base station and GNSS is the same. Therefore, when the terminal to be synchronized detects the synchronization signal of the TDD base station or the synchronization signal of the terminal synchronized to the TDD base station, it means that there is a current application scenario. GNSS.
  • the synchronization signal of the target terminal is searched, wherein the target terminal is a terminal synchronized to the base station in the TDD communication mode (ie, the terminal synchronized to the TDD base station), or the target terminal is located within the coverage of the base station in the TDD communication mode. Therefore, the target terminal can be denoted as TDD IC UE.
  • the terminal to be synchronized can determine whether the terminal is a TDD IC UE by whether the broadcast channel that sends the synchronization signal carries the uplink and downlink time configuration information or TDD indication.
  • the second type of device is a base station in a TDD communication mode.
  • the terminal to be synchronized may also judge whether synchronization needs to be performed according to the target synchronization priority configuration information by judging whether a synchronization signal of the second type of device is searched:
  • the terminal to be synchronized determines that the target synchronization priority configuration information is required for synchronization, and starts to perform the synchronization process in S301-S302;
  • the terminal to be synchronized can use the traditional synchronization priority configuration to perform the synchronization process, and the specific process can refer to the aforementioned related content, which will not be repeated here.
  • the step of judging whether the synchronization signal of the second type of device is found is an optional step.
  • the terminal to be synchronized may or may not perform this step. , which is not limited in the embodiments of the present application.
  • the terminal to be synchronized if the terminal to be synchronized does not search for the synchronization signal of the first type of equipment or the synchronization signal of the second type of equipment, the terminal to be synchronized needs to perform all searches, so that the search synchronization priority is higher the synchronization signal of the terminal. Therefore, in the process of performing S302 on the terminal device to be synchronized, there may exist a third-type device or a fourth-type device as a synchronization source, wherein the fourth-type device is a terminal synchronized to the third-type device (that is, Indirectly sync to the terminal of the first class device).
  • the terminal to be synchronized will always search all the time, so that the terminal with higher synchronization priority and reliable signal quality of the synchronization signal can be searched, unless the terminal to be synchronized searches for the first type of equipment or the second type of equipment. synchronization signal. Therefore, reducing the time for the terminal to be synchronized to perform all searches in the process when the current synchronization source is the terminal can also significantly reduce the power consumption of the terminal to be synchronized.
  • the time domain positions of the devices with the same synchronization source or related synchronization sources sending synchronization signals are relatively close.
  • the synchronization signal transmission time of the terminals related to the base station should be the same, but considering the delay deviation of different terminals and Due to factors such as coverage, the time difference between the transmission synchronization times between these terminals is small.
  • the time difference between the GNSS-related terminals (the third type of terminal (GNSS UE) and the fourth type of terminal (sync with GNSS UE)) for sending synchronization signals is also small.
  • the terminal to be synchronized when the current synchronization source of the terminal to be synchronized is a terminal (for example, the third type device or the fourth type device), the terminal to be synchronized performs synchronization through the following steps :
  • A1 The terminal to be synchronized determines a first time range according to the synchronization information of the current synchronization source
  • A2 The terminal to be synchronized searches for a synchronization signal within the first time range.
  • the first time range may also be referred to as a search time range, which is a time range in which the terminal to be synchronized performs the search.
  • the first time range is a time range for the terminal to be synchronized to search for synchronization signals of other terminals related to the current synchronization source.
  • the synchronization information of the current synchronization source may be the device type of the current synchronization source, the time domain information of the synchronization signal of the current synchronization source, etc., which is not limited in this application.
  • information such as the time domain position of the synchronization signal sent by the current synchronization source or the duration of the synchronization signal can be determined.
  • the terminal to be synchronized does not search for synchronization signals outside the first time range. Therefore, compared with the traditional full search, this implementation can greatly reduce the time for the terminal to be synchronized to perform the full search, thereby significantly reducing the time required for the terminal to be synchronized. Reduce the power consumption of the terminal to be synchronized.
  • the search when the terminal to be synchronized performs the search for the synchronization signal within the first time range, the search may be performed in all time units within the first time range, or The search is performed in part of time units (subframes or time slots) within the first time range, which is not limited in this application.
  • the time domain position of the part of the time unit where the search is performed may be continuous or discrete, which is not limited in this application.
  • the synchronization information of the current synchronization source includes synchronization signal time domain information, and the synchronization signal time domain information is used to indicate a first duration, and the first duration is the duration of the synchronization signal sent by the current synchronization source.
  • the terminal to be synchronized can perform the above step A1 through the following steps:
  • B1 Determine the first time range according to the time domain information of the synchronization signal.
  • the time domain information of the synchronization signal may be specified in a protocol, or configured for the base station or GNSS accessed by the terminal to be synchronized, or configured for the current synchronization source (before the current synchronization source leaves the factory).
  • the synchronization signal time domain information may be preconfigured in the current synchronization source), which is not limited in this embodiment of the present application.
  • the synchronization signal time domain information of GNSS is pre-configured before the factory to be synchronized, or pre-configured by protocols or managers;
  • the time domain information of the synchronization signal may be pre-configured by the terminal to be synchronized before leaving the factory, or pre-configured by a protocol or an administrator, or may be configured by the base station.
  • the time domain information of the synchronization signal may indicate the first duration in the following manners, but not limited to:
  • the synchronization signal time domain information includes the first duration (the duration of the synchronization signal sent by the current synchronization source).
  • the time domain information of the synchronization signal includes: a duration indication.
  • the duration indication corresponds to the first duration. Then the terminal to be synchronized can determine the first duration corresponding to the duration indication.
  • the synchronization signal time domain information may further include the following parameters: the number of synchronization signals in the synchronization signal transmission period; the time offset of the first synchronization signal in the synchronization signal transmission period; and when the synchronization signal transmission period When the data amount of the inner synchronization signal is greater than 1, the time interval between two adjacent synchronization signals.
  • the time domain information of the synchronization signal may be represented as an SL-SSB configuration time (SL-SSB-TimeAllocation).
  • SL-SSB-TimeAllocation the following three parameters can be included in SL-SSB-TimeAllocation:
  • the number of SL-SSBs in the SL-SSB period ie (SL-NumSSB-WithinPeriod), is used to indicate the number of SL-SSBs sent in one SL-SSB period.
  • the time offset of the first SL-SSB namely (SL-TimeOffsetSSB), is used to represent the time offset from the start of the SL-SSB period to the time domain position of the first SL-SSB.
  • the duration of the first time range is greater than or equal to the first duration indicated by the time domain information of the synchronization signal.
  • the duration of the first time range may be greater than the first duration indicated by the synchronization signal time domain information.
  • the current synchronization source is the first type terminal/the second type terminal, then the other terminals related to the current synchronization source are the first type terminal and the second type terminal.
  • the current synchronization source is the third type terminal/fourth type terminal, then other terminals related to the current synchronization source are the third type terminal and the fourth type terminal.
  • the terminal to be synchronized may determine the time domain position of the first time range in the following manner:
  • the start position of the first time range is located before the first time domain position, or is equal to the first time domain position; and/or, the end position of the first time range is located after the second time domain position, or is equal to the second time domain position;
  • the first time domain position is the time domain position where the terminal to be synchronized searches for the synchronization signal of the current synchronization source; the second time domain position is located after the first time domain position, and is different from the The interval duration between the first time domain positions is equal to the first duration indicated by the time domain information of the synchronization signal.
  • the start position of the first time range is located before the first time domain position, and/or the The end position of the first time range is located after the second time domain position.
  • the first time range may include part or all of the symbols in the second time range; and/or, the first time range may include part or all of the symbols in the third time range; wherein the second time range The time range is the time range between the start position of the first time range and the first time domain position, and the third time range is the time range between the second time domain position and the first time range The time range between the end positions of .
  • the second time range may be one or more time units, for example, one time slot or two time slots.
  • the third time range may also be one or more time units, such as 1 time slot or 2 time slots.
  • the terminal to be synchronized does not search for the synchronization signal of any terminal within the first time range (and does not search for the synchronization signal of the first type of device), then the terminal to be synchronized is at the fourth time.
  • Searching for synchronization signals in all time units within the range eg, search time period, frame
  • the terminal to be synchronized can search for the synchronization signal of the terminal through all search to achieve synchronization.
  • the terminal to be synchronized does not search for a synchronization signal of any type of device within the first time range, it searches for a synchronization signal on each subframe in the frame.
  • the first time range is used to search for the third-type device or the fourth-type device. Therefore, when the terminal to be synchronized fails to search for the synchronization signal of the third-type device or the fourth-type device within the first time range, it returns to all search.
  • the terminal to be synchronized needs to search for synchronization signals of all terminals during the entire search process, and also needs to compare the reliability of the searched synchronization signals, which also causes high power consumption of the terminal to be synchronized.
  • the terminal to be synchronized can search for synchronization signals by the following methods:
  • the terminal to be synchronized searches for the synchronization signal of the first terminal (or after searching for the synchronization signal of the first terminal), it continues to search for the synchronization signal of at least one target class device.
  • the sequence of the synchronization signal of the device of the at least one target class is within the set signal sequence range, and the synchronization priority of each device of the target class is higher than or equal to the synchronization priority of the first terminal.
  • the first terminal belongs to the third type of equipment or the fourth type of equipment.
  • the devices of the at least one target class may further include at least one class of devices of the first class and devices of the second class.
  • the terminal to be synchronized executes the search method in this implementation when it searches for a synchronization signal of the first terminal and determines that the signal quality of the synchronization signal of the first terminal is greater than a set threshold.
  • the terminal to be synchronized may not need to search and compare the synchronization priority lower than that of the first terminal.
  • the first terminal is the synchronization signal of other types of terminals, so that the power consumption of the terminal device can be reduced.
  • the terminal to be synchronized can also search for synchronization signals by the following methods:
  • the terminal to be synchronized searches for the synchronization signal of the first terminal (or after searching for the synchronization signal of the first terminal), it continues to search for the synchronization signal within the range of the set signal sequence.
  • the synchronization signal within the set signal sequence range is the synchronization signal of at least one target class device.
  • the synchronization priority of each target class device is higher than or equal to the synchronization priority of the first terminal.
  • the first terminal belongs to the third type of equipment or the fourth type of equipment.
  • the devices of the at least one target class include devices of the first class and devices of the second class.
  • the terminal to be synchronized executes the search method in this implementation when it searches for a synchronization signal of the first terminal and determines that the signal quality of the synchronization signal of the first terminal is greater than a set threshold.
  • the communication system may set a range for the signal sequence of the synchronization signal of each type of terminal.
  • SL-SSB for the first type of terminal IC UE
  • SL-SSB for the second type of terminal SL-SSB for the third type of terminal
  • GNSS UE GNSS UE
  • fourth type of terminal SL-SSB with GNSS UE
  • the synchronization signals of the first type of equipment and the second type of equipment may be within a preset signal sequence range.
  • the signal sequence range of the synchronization signal of the device of each target class can be determined; then according to the range of the synchronization signal of the device of each target class The signal sequence range is compared with the received signal, enabling coherent calculations. Since there is no need to compare synchronization signals of other types of terminals with a synchronization priority lower than that of the first terminal, the power consumption of the terminal device can be reduced.
  • the embodiments of the present application provide a synchronization method.
  • the synchronization priority of the first type of equipment is the highest, and the synchronization priority of the second type of equipment is higher than or equal to that of the third type of equipment.
  • the terminal to be synchronized can preferentially synchronize to the second type of device when the synchronization signal of the first type of device is not found or when the signal quality of the synchronization signal of the first type of device is found to be lower than the set threshold, so that the terminal to be synchronized can
  • the second type of device is preferred as the synchronization source.
  • the second type of equipment is a base station or GNSS, that is, the resources used by the second type of equipment to send synchronization signals are fixed resources, therefore, if the terminal to be synchronized is not synchronized to the first type of equipment, it is not necessary to search for the first type of equipment.
  • the synchronization signal of the second-class device and when the terminal to be synchronized uses the second-class device as the synchronization source, there is no need to perform all searches. Therefore, compared with the traditional synchronization priority configuration, the method can significantly reduce the probability that the terminal to be synchronized performs the search for the synchronization signal, thereby reducing the power consumption caused by the search for the synchronization signal.
  • the embodiment of the present application further provides another synchronization method.
  • the method can be applied to the terminals to be synchronized (for example, terminal a-terminal e) supporting sidelink communication in the application scenario shown in FIG. 2 . It can be seen from the descriptions in the above embodiments that when the synchronization source of the terminal to be synchronized is a terminal, the terminal to be synchronized needs to perform all searches to search for the synchronization signal of the terminal with a higher synchronization priority.
  • the terminal to be synchronized will always search all the time, so that the terminal with higher synchronization priority and the signal quality exceeding the set threshold can be searched, unless the terminal to be synchronized searches for the base station with the highest synchronization priority or the GNSS Sync signal and sync to base station or GNSS. Therefore, reducing the time for the terminal to be synchronized to perform all searches in the process when the current synchronization source is the terminal can also significantly reduce the power consumption of the terminal to be synchronized.
  • the terminal to be synchronized determines a first time range according to synchronization information of the current synchronization source.
  • the first time range may also be referred to as a search time range, which is a time range in which the terminal to be synchronized performs the search.
  • the first time range is a time range for the terminal to be synchronized to search for synchronization signals of other terminals related to the current synchronization source.
  • the synchronization information of the current synchronization source may be the device type of the current synchronization source, the time domain information of the synchronization signal of the current synchronization source, etc., which is not limited in this application.
  • information such as the time domain position of the synchronization signal sent by the current synchronization source or the duration of the synchronization signal can be determined.
  • S402 The terminal to be synchronized searches for a synchronization signal within the first time range.
  • the terminal to be synchronized does not search for synchronization signals outside the first time range. Therefore, compared with the traditional full search, this implementation can greatly reduce the time for the terminal to be synchronized to perform all searches, so that it can be Significantly reduces the power consumption of the terminal to be synchronized.
  • the search when the terminal to be synchronized performs the search for the synchronization signal within the first time range, the search may be performed in all time units within the first time range, or may be performed in all time units.
  • the search is performed in part of time units (subframes or time slots) within the first time range, which is not limited in this application.
  • the time domain position of the part of the time unit where the search is performed may be continuous or discrete, which is not limited in this application.
  • the synchronization information of the current synchronization source includes synchronization signal time domain information, and the synchronization signal time domain information is used to indicate a first duration, and the first duration is the synchronization signal sent by the current synchronization source.
  • the duration of the signal may be performed by the terminal to be synchronized through the following steps: determining the first time range according to the time domain information of the synchronization signal.
  • the acquisition method of the synchronization signal time domain information, the indication method of the synchronization signal time domain information indicating the first duration, and the process of determining the first time range according to the synchronization signal time domain information can all be Referring to the corresponding description in the embodiment shown in FIG. 3 , details are not repeated here.
  • the terminal to be synchronized does not search for a synchronization signal of any type of device within the first time range, then the terminal to be synchronized is in the fourth time range (eg, search time period, frame) for the entire time period.
  • Searching for the synchronization signal on the unit means returning to all search, so that the terminal to be synchronized can search for the synchronization signal of the terminal through all search to achieve synchronization.
  • the terminal to be synchronized does not search for a synchronization signal of any type of device within the first time range, it searches for a synchronization signal on each subframe in the frame.
  • the terminal to be synchronized needs to search for synchronization signals of all terminals during the entire search process, and also needs to compare the reliability of the searched synchronization signals, which also causes high power consumption of the terminal to be synchronized.
  • the terminal to be synchronized can search for synchronization signals by the following methods:
  • the terminal to be synchronized searches for the synchronization signal of the first terminal (or after searching for the synchronization signal of the first terminal), it continues to search for the synchronization signal of at least one target class device.
  • the sequence of the synchronization signal of the device of the at least one target class is within the set signal sequence range, and the synchronization priority of each device of the target class is higher than or equal to the synchronization priority of the first terminal.
  • the device of the at least one target class may include a base station and a GNSS.
  • the terminal to be synchronized can also search for synchronization signals by the following methods:
  • the terminal to be synchronized searches for the synchronization signal of the first terminal (or after searching for the synchronization signal of the first terminal), it continues to search for the synchronization signal within the range of the set signal sequence.
  • the synchronization signal within the set signal sequence range is the synchronization signal of at least one target class device.
  • the synchronization priority of each target class device is higher than or equal to the synchronization priority of the first terminal.
  • the terminal to be synchronized searches for the synchronization signal of the first terminal, and determines that the signal quality of the synchronization signal of the first terminal is greater than the set threshold, the above search process is performed again. .
  • the terminal to be synchronized does not need to search and compare the synchronization priority
  • the level is lower than the synchronization signals of other types of terminals of the first terminal, so that the power consumption of the terminal equipment can be reduced.
  • the communication system may set a range for the signal sequence of the synchronization signal of each type of terminal.
  • SL-SSB for the first type of terminal IC UE
  • SL-SSB for the second type of terminal SL-SSB for the third type of terminal
  • GNSS UE GNSS UE
  • fourth type of terminal sync with IC UE with GNSS UE
  • the signal sequences of the first type of equipment and the second type of equipment are fixed.
  • the signal sequence range of the synchronization signal of the device of each target class can be determined; then according to the range of the synchronization signal of the device of each target class The signal sequence range is compared with the received signal, enabling coherent calculations. Since there is no need to compare synchronization signals of other types of terminals with a synchronization priority lower than that of the first terminal, the power consumption of the terminal device can be reduced.
  • the terminal to be synchronized needs to search for synchronization signals of all terminals during the entire search process, and also needs to compare the reliability of the searched synchronization signals, which also causes high power consumption of the terminal to be synchronized.
  • the embodiment of the present application further provides another synchronization method.
  • the method can be applied to the terminals to be synchronized (for example, terminal a-terminal e) supporting sidelink communication in the application scenario shown in FIG. 2 .
  • the synchronization signal is searched according to the target synchronization priority configuration information; wherein the target synchronization priority configuration information is used to indicate the synchronization priorities of different types of devices.
  • the target synchronization priority configuration information may be traditional synchronization priority configuration information (such as shown in FIG. 1A-FIG. 1C ), or may also be the target synchronization priority configuration information provided in the embodiment shown in FIG. 3 , This application does not limit this.
  • the terminal to be synchronized may search for a synchronization signal according to the target synchronization priority configuration information in the following two implementation manners:
  • the first implementation manner when the terminal to be synchronized searches for the synchronization signal of the first terminal (or after searching for the synchronization signal of the first terminal), it continues to search for the synchronization signal of at least one target class device.
  • the sequence of the synchronization signal of the device of the at least one target class is within the set signal sequence range, and the synchronization priority of each device of the target class is higher than or equal to the synchronization priority of the first terminal.
  • the second implementation manner when the terminal to be synchronized searches for the synchronization signal of the first terminal (or after searching for the synchronization signal of the first terminal), it continues to search for the synchronization signal within the set signal sequence range.
  • the synchronization signal within the set signal sequence range is the synchronization signal of at least one target class device.
  • the synchronization priority of each target class device is higher than or equal to the synchronization priority of the first terminal.
  • the device of the at least one target class may include a base station and a GNSS.
  • the terminal to be synchronized searches for the synchronization signal of the first terminal, and determines that the signal quality of the synchronization signal of the first terminal is greater than the set threshold, the above search process is performed again. .
  • the terminal to be synchronized can be searched and compared without the need for The synchronization priority is lower than that of the synchronization signals of other types of terminals of the first terminal, so that the power consumption of the device to be synchronized can be reduced.
  • the communication system may set a range for the signal sequence of the synchronization signal of each type of terminal.
  • SL-SSB for the first type of terminal IC UE
  • SL-SSB for the second type of terminal SL-SSB for the third type of terminal
  • GNSS UE GNSS UE
  • fourth type of terminal sync with IC UE with GNSS UE
  • the signal sequences of the first type of equipment and the second type of equipment are fixed.
  • the signal sequence range of the synchronization signal of the device of each target class can be determined; then according to the range of the synchronization signal of the device of each target class The signal sequence range is compared with the received signal, enabling coherent calculations. Since there is no need to compare synchronization signals of other types of terminals with a synchronization priority lower than that of the first terminal, the power consumption of the terminal device can be reduced.
  • the set threshold for judging the reliability of the synchronization signal may be determined by the terminal to be synchronized, or set by the terminal to be synchronized when it accesses a network device (base station or GNSS). Configured by the network device or specified by the protocol.
  • the set threshold may refer to the signal quality threshold in protocol 38.331, for example, the set threshold may be used for the threshold (Srxlev) used for cell selection, and the like.
  • the present application also provides the following examples. Each example is described below.
  • the following examples 1 to 3 are that the synchronization priority configuration parameter (SL-SyncPriority) of the terminal to be synchronized is configured as GNSS indication information, and whether the base station is a synchronization source configuration parameter (SL-NbAsSync) is configured as the first indication information (eg yes) Instances of synchronization priority configuration information.
  • SL-SyncPriority synchronization priority configuration parameter
  • SL-NbAsSync synchronization source configuration parameter
  • the base stations are divided into two categories in Examples 1 to 3: TDD base stations and FDD base stations.
  • the synchronization priority of the TDD base station is set to be greater than or equal to the synchronization priority of the third type of terminal (terminal directly synchronized to the GNSS, GNSS UE). class.
  • the synchronization priority of the TDD base station can be raised to the front of the third type of terminal (ie, the terminal directly synchronized to the GNSS, GNSS UE), that is, P1: TDD base station;
  • P1 TDD base station
  • the order of synchronization priorities of the FDD base station remains unchanged, and the synchronization priorities of other types of equipment such as the third-type terminal, the fourth-type terminal, and the FDD base station are sequentially extended, and the order remains unchanged.
  • the synchronization priorities of different types of devices in Example 1 are shown in FIG. 5A .
  • the synchronization is performed with the TDD base station according to the synchronization signal of the TDD base station;
  • the synchronization signal of the GNSS and the synchronization signal of the TDD base station are not searched, and the synchronization signal of the third type of terminal (the terminal directly synchronized to the GNSS, GNSS UE) is searched, according to the synchronization signal of the third type of terminal and the third type of terminal.
  • the terminal is synchronized;
  • the synchronization priority of the TDD base station can be raised to be the same as that of the GNSS, that is, P0: GNSS or TDD base station; while the order of the synchronization priority of the FDD base station remains unchanged. , and the order of synchronization priorities of other types of devices such as the third-type terminal and the fourth-type terminal also remains unchanged.
  • the synchronization priorities of different types of devices in Example 2 are shown in Figure 5B.
  • the synchronization signal of the GNSS and the synchronization signal of the TDD base station are not searched, and the synchronization signal of the third type of terminal (the terminal directly synchronized to the GNSS, GNSS UE) is searched, according to the synchronization signal of the third type of terminal and the third type of terminal.
  • the terminal is synchronized;
  • the synchronization priority of the TDD base station can be increased to be the same as that of the third type of terminal, that is, P1: TDD base station or third type of terminal; and the synchronization priority of the FDD base station.
  • the order of the tiers remains unchanged, and the order of synchronization priorities of other types of devices such as the fourth type of terminals also remains unchanged.
  • the synchronization priorities of different types of devices in Example 3 are shown in FIG. 5C .
  • the synchronization is performed with the TDD base station according to the synchronization signal of the TDD base station;
  • the synchronization is performed with the third-type terminal according to the synchronization signal of the third-type terminal;
  • the synchronization is performed with the TDD base station according to the synchronization signal of the TDD base station. That is, when the terminal to be synchronized searches for the synchronization signals of the TDD base station and the third-type terminal at the same time, it preferentially selects the TDD base station for synchronization; or
  • the synchronization signal of the GNSS and the synchronization signal of the TDD base station are not searched, and the synchronization signal of the third type of terminal (the terminal directly synchronized to the GNSS, GNSS UE) is searched, according to the synchronization signal of the third type of terminal and the third type of terminal.
  • the terminal is synchronized;
  • the terminal to be synchronized searches for the synchronization signal of the TDD base station, the signal quality of the synchronization signal of the TDD base station is greater than or equal to the set threshold, and the terminal to be synchronized is determined.
  • the terminal to be synchronized performs synchronization according to the synchronization signal of the TDD base station, that is, selects the TDD base station as the synchronization source.
  • the terminal to be synchronized will no longer use the TDD base station as the synchronization source.
  • the following examples 4 to 6 are examples of the synchronization priority configuration information in the case that the synchronization priority configuration parameter (SL-SyncPriority) of the terminal to be synchronized is the base station indication information.
  • the terminal to be synchronized searches for a synchronization signal of a terminal that is directly synchronized to the TDD base station (or a terminal within the coverage of the TDD base station, TDD IC UE), it means that GNSS exists in the current scene.
  • the synchronization priorities of different types of devices are as shown in Examples 4 to 6, wherein the synchronization priority of GNSS is set to be greater than or equal to the synchronization priority of the first type of terminal (terminal directly synchronized to the base station, IC UE) class.
  • the terminal to be synchronized does not search for the synchronization signal of the TDD IC UE, the terminal to be synchronized can continue to use the traditional synchronization priority configuration, as shown in Figure 1A.
  • the synchronization priority of GNSS can be raised before the first type of terminal (ie, the terminal that is directly synchronized to the base station, IC UE), that is, P1: GNSS; first
  • the synchronization priorities of other types of devices, such as class terminals and second class terminals, are sequentially extended, and the order remains unchanged.
  • the synchronization priorities of different types of devices in Example 4 are shown in Figure 5D.
  • the terminal to be synchronized when the terminal to be synchronized searches for a synchronization signal of a terminal that is directly synchronized to the TDD base station (or a terminal within the coverage of the TDD base station, TDD IC UE), the terminal to be synchronized takes priority according to the synchronization shown in Figure 5D During synchronization of level configuration information:
  • the synchronization is performed with the GNSS according to the synchronization signal of the GNSS;
  • the synchronization signal of the base station and the synchronization signal of the GNSS are not searched, and the synchronization signal of the first type of terminal (terminal directly synchronized to the base station, IC UE) is searched, according to the synchronization signal of the first type of terminal and the first type of terminal to synchronize;
  • the synchronization priority of the GNSS can be raised to be the same as that of the base station, that is, P0: base station or GNSS;
  • the synchronization priorities are successively deferred, and the order remains unchanged.
  • the synchronization priorities of different types of devices in Example 5 are shown in FIG. 5E .
  • the terminal to be synchronized when the terminal to be synchronized searches for a synchronization signal of a terminal that is directly synchronized to the TDD base station (or a terminal within the coverage of the TDD base station, TDD IC UE), the terminal to be synchronized takes priority according to the synchronization shown in Figure 5E During synchronization of level configuration information:
  • the synchronization signal of the base station and the synchronization signal of the GNSS are not searched, and the synchronization signal of the first type of terminal (terminal directly synchronized to the base station, IC UE) is searched, according to the synchronization signal of the first type of terminal and the first type of terminal to synchronize;
  • the synchronization priority of GNSS can be raised to be the same as that of the first type of terminal, that is, P1: GNSS or first type of terminal; second type of terminal and other types of equipment.
  • the synchronization priority of and the order remains unchanged.
  • the synchronization priorities of different types of devices in Example 5 are shown in Figure 5F.
  • the terminal to be synchronized when the terminal to be synchronized searches for a synchronization signal of a terminal that is directly synchronized to the TDD base station (or a terminal within the coverage of the TDD base station, TDD IC UE), the terminal to be synchronized takes priority according to the synchronization shown in Figure 5F During synchronization of level configuration information:
  • the synchronization is performed with the GNSS according to the synchronization signal of the GNSS;
  • the synchronization signal of the base station is not searched, and the synchronization signal of the first type of terminal (terminal directly synchronized to the base station, IC UE) is searched, the synchronization is performed with the first type of terminal according to the synchronization signal of the first type of terminal; or
  • the synchronization signal of the base station When the synchronization signal of the base station is not searched, and the synchronization signal of the GNSS and the synchronization signal of the first type of terminal (terminal directly synchronized to the base station, IC UE) are searched, the synchronization is performed with the GNSS according to the synchronization signal of the GNSS. That is, when the terminal to be synchronized searches for the synchronization signal of the GNSS and the first type of terminal at the same time, it preferentially selects the GNSS for synchronization; or
  • the synchronization signal of the base station and the synchronization signal of the GNSS are not searched, and the synchronization signal of the first type of terminal (terminal directly synchronized to the base station, IC UE) is searched, according to the synchronization signal of the first type of terminal and the first type of terminal to synchronize;
  • the terminal to be synchronized searches for a GNSS synchronization signal, the signal quality of the GNSS synchronization signal is greater than or equal to a set threshold, and the current status of the terminal to be synchronized is determined.
  • the terminal to be synchronized performs synchronization according to the synchronization signal of the GNSS, that is, selects the GNSS as the synchronization source.
  • the terminal to be synchronized no longer uses the GNSS as the synchronization source.
  • the above examples 1 to 6 are the synchronization priority configuration of each different type of equipment in consideration of the relationship between the TDD base station and the GNSS.
  • the following examples 7 to 12 are the synchronization priority configuration information without considering the relationship between the TDD base station and the GNSS.
  • the synchronization priority configuration parameter (SL-SyncPriority) of the terminal to be synchronized is the GNSS indication information, and whether the base station is the synchronization source configuration parameter (SL-NbAsSync) is configured as the first indication information (for example, yes) Instances of synchronization priority configuration information.
  • Example 7 Compared with the traditional synchronization priority configuration shown in FIG. 1B , in this example, the synchronization priority of the base station can be increased before the third type of terminal (ie, the terminal directly synchronized to the GNSS, GNSS UE), that is, P1: The base station; and the synchronization priorities of the third-type terminals and the fourth-type terminals are sequentially extended, and the order remains unchanged.
  • the synchronization priorities of different kinds of devices in Example 7 are shown in Figure 5G.
  • the synchronization is performed with the base station according to the synchronization signal of the base station;
  • the synchronization signal of the GNSS and the synchronization signal of the base station are not searched, and the synchronization signal of the third-type terminal (the terminal directly synchronized to the GNSS, GNSS UE) is searched, according to the synchronization signal of the third-type terminal and the third-type terminal to synchronize;
  • Example 8 Compared with the traditional synchronization priority configuration shown in FIG. 1B , in this example, the synchronization priority of the base station can be increased to be the same as that of GNSS, that is, P0: GNSS or base station; The synchronization priority order of .
  • the synchronization priorities of different types of devices in Example 8 are shown in Figure 5H.
  • the synchronization signal of the GNSS and the synchronization signal of the base station are not searched, and the synchronization signal of the third-type terminal (the terminal directly synchronized to the GNSS, GNSS UE) is searched, according to the synchronization signal of the third-type terminal and the third-type terminal to synchronize;
  • Example 9 Compared with the traditional synchronization priority configuration shown in FIG. 1B , in this example, the synchronization priority of the base station can be increased to be the same as that of the third type of terminal (ie, the terminal directly synchronized to the GNSS, GNSS UE), that is, P1 : base station or the third type of terminal; and the synchronization priority order of other types of equipment such as the fourth type of terminal remains unchanged.
  • the synchronization priorities of different kinds of devices in Example 9 are shown in Figure 5I.
  • the synchronization is performed with the third-type terminal according to the synchronization signal of the third-type terminal;
  • the synchronization is performed with the base station according to the synchronization signal of the base station. That is, when the terminal to be synchronized searches for the synchronization signals of the base station and the third-type terminal at the same time, it preferentially selects the base station for synchronization; or
  • the synchronization signal of the GNSS and the synchronization signal of the base station are not searched, and the synchronization signal of the third-type terminal (the terminal directly synchronized to the GNSS, GNSS UE) is searched, according to the synchronization signal of the third-type terminal and the third-type terminal to synchronize;
  • the terminal to be synchronized searches for the synchronization signal of the base station, the signal quality of the synchronization signal of the base station is greater than or equal to the set threshold, and the terminal to be synchronized is determined to be
  • the terminal to be synchronized performs synchronization according to the synchronization signal of the base station, that is, selects the base station as the synchronization source.
  • the terminal to be synchronized no longer uses the base station as the synchronization source.
  • the following examples ten to twelve are examples of the synchronization priority configuration information in the case that the synchronization priority configuration parameter (SL-SyncPriority) of the terminal to be synchronized is the base station indication information.
  • Example 10 Compared with the traditional synchronization priority configuration shown in FIG. 1A , in this example, the synchronization priority of GNSS can be increased before the first type of terminal (ie, the terminal directly synchronized to the base station, IC UE), namely P1: GNSS; while the synchronization priorities of the first type of terminals and the second type of terminals are sequentially extended, and the order remains unchanged.
  • the synchronization priorities of different types of devices in Example 10 are shown in Figure 5D.
  • the terminal to be synchronized performs synchronization according to the synchronization priority configuration information shown in FIG. 5D :
  • the synchronization is performed with the GNSS according to the synchronization signal of the GNSS;
  • the synchronization signal of the base station and the synchronization signal of the GNSS are not searched, and the synchronization signal of the first type of terminal (terminal directly synchronized to the base station, IC UE) is searched, according to the synchronization signal of the first type of terminal and the first type of terminal to synchronize;
  • Example 11 Compared with the traditional synchronization priority configuration shown in FIG. 1B, in this example, the synchronization priority of the GNSS can be increased to be the same as that of the base station, that is, P0: base station or GNSS; The synchronization priority order of the endpoints remains unchanged.
  • the synchronization priorities of different kinds of devices in Example 11 are shown in FIG. 5E .
  • the terminal to be synchronized performs synchronization according to the synchronization priority configuration information shown in FIG. 5E:
  • the synchronization signal of the base station and the synchronization signal of the GNSS are not searched, and the synchronization signal of the first type of terminal (terminal directly synchronized to the base station, IC UE) is searched, according to the synchronization signal of the first type of terminal and the first type of terminal to synchronize;
  • Example 12 Compared with the traditional synchronization priority configuration shown in FIG. 1B , in this example, the synchronization priority of the GNSS can be increased to be the same as that of the first type of terminal (ie, the terminal directly synchronized to the base station, IC UE), that is, P1: GNSS or the first type of terminal; and the synchronization priority order of other types of equipment such as the second type of terminal remains unchanged.
  • the synchronization priorities of different kinds of devices in Example Twelve are shown in Figure 5F.
  • the terminal to be synchronized performs synchronization according to the synchronization priority configuration information shown in FIG. 5F :
  • the synchronization is performed with the GNSS according to the synchronization signal of the GNSS;
  • the synchronization signal of the base station is not searched, and the synchronization signal of the first type of terminal (terminal directly synchronized to the base station, IC UE) is searched, the synchronization is performed with the first type of terminal according to the synchronization signal of the first type of terminal; or
  • the synchronization signal of the base station When the synchronization signal of the base station is not searched, and the synchronization signal of the GNSS and the synchronization signal of the first type of terminal (terminal directly synchronized to the base station, IC UE) are searched, the synchronization is performed with the GNSS according to the synchronization signal of the GNSS. That is, when the terminal to be synchronized searches for the synchronization signal of the GNSS and the first type of terminal at the same time, it preferentially selects the GNSS for synchronization; or
  • the synchronization signal of the base station and the synchronization signal of the GNSS are not searched, and the synchronization signal of the first type of terminal (terminal directly synchronized to the base station, IC UE) is searched, according to the synchronization signal of the first type of terminal and the first type of terminal to synchronize;
  • the terminal to be synchronized searches for a GNSS synchronization signal, the signal quality of the GNSS synchronization signal is greater than or equal to a set threshold, and the terminal to be synchronized is determined to be
  • the terminal to be synchronized performs synchronization according to the synchronization signal of the GNSS, that is, selects the GNSS as the synchronization source.
  • the terminal to be synchronized no longer uses the GNSS as the synchronization source.
  • the synchronization priority of the first type of device is the highest, and the synchronization priority of the second type of device is higher than or equal to the synchronization priority of the third type of device; wherein, When the first type of equipment is a base station, the second type of equipment is a GNSS; when the first type of equipment is a GNSS, the second type of equipment is a base station; and the third type of equipment is a terminal synchronized to the first type of equipment.
  • the terminal to be synchronized can preferentially synchronize to the second type of device when the synchronization signal of the first type of device is not found or when the signal quality of the synchronization signal of the first type of device is found to be lower than the set threshold, so that the terminal to be synchronized can
  • the second type of device is preferred as the synchronization source. Since the second type of equipment is a base station or GNSS, that is, the resources used by the second type of equipment to send synchronization signals are fixed resources, therefore, if the terminal to be synchronized is not synchronized to the first type of equipment, it is not necessary to search for the first type of equipment.
  • the synchronization signal of the second-class device and when the terminal to be synchronized uses the second-class device as the synchronization source, there is no need to perform all searches. Therefore, compared with the traditional synchronization priority configuration, the methods provided by the above examples can significantly reduce the probability that the terminal to be synchronized performs all searches, that is, the chance of performing the search for the synchronization signal during the synchronization to be synchronized, thereby reducing the cause caused by the execution of the search for the synchronization signal. power consumption.
  • Example 13 and Example 14 the time range for all searches—the first time range—can be set to reduce the time for the terminal to be synchronized to perform all searches, thereby reducing the power consumption of the terminal to be synchronized.
  • the first time range can be determined according to the synchronization information of the current synchronization source of the device to be synchronized, so that the terminal to be synchronized can In the first time range, the synchronization signal of the current synchronization source and the synchronization signals of other terminals related to the current synchronization source can be searched.
  • the current synchronization source is a terminal that is directly (or indirectly) synchronized to the target base station
  • other terminals related to the current synchronization source may be other terminals that are directly synchronized to the target base station and other terminals that are indirectly synchronized to the target base station.
  • the current synchronization source is a terminal that is directly (or indirectly) synchronized to the target GNSS
  • other terminals related to the current synchronization source may be other terminals that are directly synchronized to the target GNSS, and other terminals that are indirectly synchronized to the target GNSS .
  • Example 13 The synchronization priority configuration parameter (SL-SyncPriority) of the terminal to be synchronized is configured as base station indication information, then the terminal to be synchronized can use the traditional synchronization priority configuration information as shown in FIG. 1A for synchronization;
  • the synchronization priority configuration information shown in FIG. 5D , FIG. 5E or FIG. 5F provided in the embodiment of the application is synchronized.
  • the terminal to be synchronized can be synchronized according to the The first time range is determined by using the synchronization signal time domain information (SL-SSB-TimeAllocation) of the current synchronization source. Then, the terminal to be synchronized searches for a synchronization signal within the first time range.
  • SL-SSB-TimeAllocation synchronization signal time domain information
  • the first time range is used for the terminal to be synchronized to search for synchronization signals of other terminals related to the current synchronization source, that is, the synchronization signals of the first type terminal or the second type terminal.
  • the terminal to be synchronized determines a first duration according to SL-SSB-TimeAllocation, where the first duration is the duration of the synchronization signal sent by the current synchronization source. Then, according to the time domain position of the synchronization signal of the current synchronization source found by the terminal to be synchronized, and the first duration, the first time range is determined.
  • the first time range may be greater than or equal to the first duration.
  • the start position of the first time range is located before the first time domain position; and the end position of the first time range is located after the second time domain position.
  • the first time domain position is the time domain position where the terminal to be synchronized searches for the synchronization signal of the current synchronization source; the second time domain position is located after the first time domain position, and is different from the The interval duration between the first time domain positions is equal to the first duration.
  • the first time range may include part or all of the symbols in the second time range, and may also include part or all of the symbols in the third time range.
  • the second time range is the time range between the start position of the first time range and the first time domain position
  • the third time range is the time range between the second time domain position and the first time domain position
  • the second time range may be one time slot
  • the third time range may be one time slot.
  • the terminal to be synchronized may determine the first time range according to the first duration indicated by the time domain information of the synchronization signal, as shown in FIG. 6 .
  • the terminal to be synchronized may perform a search on some or all of the subframes within the first time range.
  • the terminal to be synchronized does not search for synchronization signals outside the first time range. Therefore, compared with the traditional full search process, this example can greatly reduce the time for the terminal to be synchronized to perform all searches, thereby significantly reducing the time to be synchronized. power consumption of the terminal.
  • the terminal to be synchronized does not search for the synchronization signal of any terminal within the first time range, in order to be able to search for the synchronization signal, the terminal to be synchronized can return to all search and perform the traditional all search. process.
  • the third type of terminal terminal synchronized directly to GNSS, GNSS UE
  • the fourth type of terminal terminal synchronized to GNSS indirectly, sync with GNSS UE
  • Example 14 When the synchronization priority configuration parameter (SL-SyncPriority) of the terminal to be synchronized is configured as GNSS indication information, and whether the base station is configured with the synchronization source configuration parameter (SL-NbAsSync) as the first indication information (for example, yes) , then the terminal to be synchronized can use the traditional synchronization priority configuration information as shown in FIG. 1B for synchronization; or can be provided according to the embodiment of the present application as shown in FIGS. 5A , 5B, 5C, 5G, 5H, 5I The synchronization priority configuration information shown is synchronized.
  • the terminal to be synchronized can be synchronized according to the The first time range is determined by using the synchronization signal time domain information (SL-SSB-TimeAllocation) of the current synchronization source. Then, the terminal to be synchronized searches for a synchronization signal within the first time range.
  • SL-SSB-TimeAllocation synchronization signal time domain information
  • the first time range is used for the terminal to be synchronized to search for synchronization signals of other terminals related to the current synchronization source, that is, synchronization signals of a third-type terminal or a fourth-type terminal.
  • the terminal to be synchronized may perform a search on some or all of the subframes within the first time range.
  • the terminal to be synchronized does not search for synchronization signals outside the first time range. Therefore, compared with the traditional full search process, this example can greatly reduce the time for the terminal to be synchronized to perform all searches, thereby significantly reducing the time to be synchronized. power consumption of the terminal.
  • the terminal to be synchronized does not search for the synchronization signal of any terminal within the first time range, in order to be able to search for the synchronization signal, the terminal to be synchronized can return to all search and perform the traditional all search. process.
  • the first type of terminals terminals that are directly synchronized to the base station, IC UE
  • the second type of terminals the terminals that are indirectly synchronized to the base station, sync with IC UE
  • Example 15 When the synchronization priority configuration parameter (SL-SyncPriority) of the terminal to be synchronized is configured as GNSS indication information, and whether the base station is configured with the synchronization source configuration parameter (SL-NbAsSync) as the second indication information (for example, no) , then the terminal to be synchronized can use the traditional synchronization priority configuration information as shown in FIG. 1C for synchronization.
  • SL-SyncPriority the synchronization priority configuration parameter of the terminal to be synchronized is configured as GNSS indication information
  • SL-NbAsSync synchronization source configuration parameter
  • the terminal to be synchronized can be synchronized according to the The first time range is determined by using the synchronization signal time domain information (SL-SSB-TimeAllocation) of the current synchronization source. Then, the terminal to be synchronized searches for a synchronization signal within the first time range.
  • SL-SSB-TimeAllocation synchronization signal time domain information
  • the first time range is used for the terminal to be synchronized to search for synchronization signals of other terminals related to the current synchronization source, that is, synchronization signals of a third-type terminal or a fourth-type terminal.
  • the terminal to be synchronized may perform a search on some or all of the subframes within the first time range.
  • the terminal to be synchronized does not search for synchronization signals outside the first time range. Therefore, compared with the traditional full search process, this example can greatly reduce the time for the terminal to be synchronized to perform all searches, thereby significantly reducing the time to be synchronized. power consumption of the terminal.
  • the terminal to be synchronized does not search for the synchronization signal of any terminal within the first time range, in order to be able to search for the synchronization signal, the terminal to be synchronized can return to all search and perform the traditional all search. process.
  • Example 16 can reduce the number of synchronization signals searched and compared by the terminal to be synchronized, thereby reducing the power consumption of the terminal to be synchronized.
  • the terminal to be synchronized performs synchronization according to the set synchronization priority configuration information according to the configuration of the synchronization priority configuration parameter (SL-SyncPriority) (and whether the base station is a synchronization source configuration parameter (SL-NbAsSync)).
  • the synchronization priority configuration information may be the conventional synchronization priority configuration information shown in FIGS. 1A to 1C , or may be the synchronization priority configuration information shown in FIGS. 5A to 5I provided in the embodiment of the present application.
  • the terminal to be synchronized searches for the synchronization signal, if the synchronization signal of the first terminal is found (or after the synchronization signal of the first terminal is found), it continues to search for the synchronization signal of at least one target class device.
  • the sequence of the synchronization signal of the device of the at least one target class is within the set signal sequence range, and the synchronization priority of each device of the target class is higher than or equal to the synchronization priority of the first terminal.
  • the terminal to be synchronized performs synchronization according to the synchronization priority configuration information shown in FIG. 1A .
  • the terminal to be synchronized In the process of searching for the synchronization signal by the terminal to be synchronized, if the synchronization signal of P1: the first type of terminal (terminal directly synchronized to the base station, IC UE) is searched, then the subsequent terminal to be synchronized only searches for P0: the base station, and P1: The synchronization signal of the first type of terminal is no longer searched for the synchronization signal of other devices whose synchronization priority is P2-P5.
  • the present application also provides a terminal, which can be applied to the application scenario shown in FIG. 2 .
  • the terminal can implement the synchronization methods provided in the above embodiments and examples, and is a terminal to be synchronized in the sidelink communication system.
  • the terminal 700 includes a communication unit 701 and a processing unit 702 .
  • the communication unit 701 is used for receiving and sending signals.
  • the physical representation of the communication unit 701 may be a transceiver, an antenna, and the like.
  • the terminal 700 can implement the synchronization method shown in FIG. 3 .
  • the processing unit 702 is configured to execute, through the communication unit 701:
  • target synchronization priority configuration information determining target synchronization priority configuration information, where the target synchronization priority configuration information is used to indicate synchronization priorities of different types of devices
  • the synchronization priority of the first type of equipment is the highest, the synchronization priority of the second type of equipment is higher than or equal to the synchronization priority of the third type of equipment, the third type of equipment to be synchronized to the terminal of the first type of device;
  • the first type of device is a GNSS
  • the second type of device is a base station
  • the first type of device is a base station
  • the second type of device is a GNSS
  • the relative relationship between the synchronization priorities of the first-type device, the second-type device, and the third-type device includes the following three situations:
  • Case 1 In the target synchronization priority configuration information, the synchronization priority of the first type of device is higher than the synchronization priority of the second type of device, and the synchronization priority of the second type of device is higher than that of all The synchronization priority of the third category of devices.
  • the processing unit 702 when performing synchronization according to the synchronization priority configuration information, is specifically configured to:
  • the synchronization is performed with the device of the second type according to the synchronization signal of the device of the second type;
  • the synchronization priority of the second type of device is equal to the synchronization priority of the first type of device, and the synchronization priority of the first type of device is the same as the synchronization priority of the first type of device.
  • the synchronization priority of the second-type device is higher than the synchronization priority of the third-type device.
  • the processing unit 702 when the processing unit 702 performs synchronization according to the synchronization priority configuration information, the processing unit 702 is specifically configured to:
  • Case 2 In the target synchronization priority configuration information, the synchronization priority of the second type of device is equal to the synchronization priority of the third type of device, and the synchronization priority of the first type of device is higher than the synchronization priority of the first type of device.
  • the synchronization priority of the second type of device and the synchronization priority of the third type of device In case 3, when the processing unit 702 performs synchronization according to the synchronization priority configuration information, the processing unit 702 is specifically configured to:
  • the synchronization is performed with the device of the third type according to the synchronization signal of the device of the third type;
  • the processing unit 702 is specifically configured to:
  • the synchronization is performed with the device of the second type according to the synchronization signal of the device of the second type;
  • the synchronization signal of the first-type device is not searched, and the synchronization signal of the second-type device and the synchronization signal of the third-type device are searched, according to the synchronization signal of the second-type device and the synchronization signal
  • the second type of equipment is used for synchronization.
  • processing unit 702 is further configured to:
  • the synchronization priority of the second-type device is higher than or equal to the synchronization priority of the current synchronization source of the terminal to be synchronized ; and/or determine that the signal quality of the synchronization signal of the second type of device is greater than or equal to a set threshold.
  • processing unit 702 is further configured to:
  • synchronization signal of the second-type device After synchronizing with the second-type device according to the synchronization signal of the second-type device, if the synchronization signal of the second-type device is not searched, or the synchronization signal of the second-type device is searched When the signal quality is lower than the set threshold, no longer synchronize with the second type of equipment according to the synchronization signal of the second type of equipment; or when the synchronization signal of the first type of equipment is found, according to the first type of equipment.
  • a synchronization signal of a class of devices is synchronized with the first class of devices.
  • processing unit 702 is further configured to:
  • the synchronization signal of the target terminal is searched, wherein the target terminal is a terminal synchronized to the base station of the time division duplex TDD communication mode, or the target terminal is located in the base station of the TDD communication mode. coverage; or search for the synchronization signal of the second type of device.
  • the second type of device is a base station in a TDD communication mode.
  • the processing unit 702 when performing synchronization according to the target synchronization priority configuration information, is specifically configured to:
  • the first time range is determined according to the synchronization information of the current synchronization source; wherein, the fourth type device is the synchronization source to the terminal of the third type of equipment;
  • a synchronization signal is searched within the first time range.
  • the synchronization information of the current synchronization source includes synchronization signal time domain information, and the synchronization signal time domain information is used to indicate a first duration, and the first duration is the duration of the synchronization signal sent by the current synchronization source.
  • the processing unit 702 when determining the first time range according to the synchronization information of the current synchronization source, is specifically configured to:
  • the first time range is determined according to the time domain information of the synchronization signal.
  • the time domain information of the synchronization signal is specified by a protocol, or configured for the base station to which the terminal to be synchronized is accessed, or configured for the current synchronization source.
  • the duration of the first time range is greater than or equal to the first duration indicated by the time domain information of the synchronization signal.
  • the start position of the first time range is located before the first time domain position, or is equal to the first time domain position; and/or, the end position of the first time range is located in the second time domain after the position, or equal to the second time domain position;
  • the first time domain position is the time domain position where the terminal to be synchronized searches for the synchronization signal of the current synchronization source; the second time domain position is located after the first time domain position, and is different from the The interval duration between the first time domain positions is equal to the first duration indicated by the time domain information of the synchronization signal.
  • the first time range includes part or all of the symbols in the second time range; and/or the first time range includes part or all of the symbols in the third time range;
  • the second time range is the time range between the start position of the first time range and the first time domain position
  • the third time range is the time range between the second time domain position and the first time domain position The time range between the end positions of the first time range.
  • processing unit 702 is further configured to:
  • the synchronization signals of the third-type device and the fourth-type device are not searched within the first time range, the synchronization signals are searched in all time units within the fourth time range.
  • the processing unit 702 when searching for a synchronization signal, is specifically configured to:
  • the synchronization signal of the first terminal When the synchronization signal of the first terminal is searched, the synchronization signal of at least one target class device is searched; wherein, the sequence of the synchronization signal of the at least one target class device is within the set signal sequence range, and each target class
  • the synchronization priority of the device is higher than or equal to the synchronization priority of the first terminal, and the first terminal belongs to the third type of equipment or the fourth type of equipment.
  • the processing unit 702 when searching for a synchronization signal, is specifically configured to:
  • the set signal sequence range is the signal sequence range where the synchronization signal sequence of at least one target class device is located , the synchronization priority of each target class device is higher than or equal to the synchronization priority of the first terminal, and the first terminal belongs to the third type device or the fourth type device.
  • the processing unit 702 when determining the target synchronization priority configuration information, is specifically configured to:
  • the indication information is used to indicate the synchronization mode
  • the target synchronization priority configuration information is determined from a plurality of synchronization priority configuration information.
  • the terminal 700 can implement the synchronization method shown in FIG. 4 .
  • the processing unit 702 is configured to execute, through the communication unit 701:
  • the current synchronization source of the terminal to be synchronized is a terminal, determining a first time range according to the synchronization information of the current synchronization source;
  • a synchronization signal is searched within the first time range.
  • the synchronization information of the current synchronization source includes synchronization signal time domain information, and the synchronization signal time domain information is used to indicate a first duration, and the first duration is the duration of the synchronization signal sent by the current synchronization source.
  • the processing unit 702 when determining the first time range according to the synchronization information of the current synchronization source, is specifically configured to:
  • the first time range is determined according to the time domain information of the synchronization signal.
  • the time domain information of the synchronization signal is specified by a protocol, or configured for the base station to which the terminal to be synchronized is accessed, or configured for the current synchronization source.
  • the duration of the first time range is greater than or equal to the first duration indicated by the time domain information of the synchronization signal.
  • the start position of the first time range is located before the first time domain position, or is equal to the first time domain position; and/or, the end position of the first time range is located at the second after the time domain position, or equal to the second time domain position;
  • the first time domain position is the time domain position where the terminal to be synchronized searches for the synchronization signal of the current synchronization source; the second time domain position is located after the first time domain position, and is different from the The interval duration between the first time domain positions is equal to the first duration indicated by the time domain information of the synchronization signal.
  • the first time range includes part or all of the symbols in the second time range; and/or the first time range includes part or all of the symbols in the third time range;
  • the second time range is the time range between the start position of the first time range and the first time domain position
  • the third time range is the time range between the second time domain position and the first time domain position The time range between the end positions of the first time range.
  • processing unit 702 is further configured to:
  • the synchronization signal is searched in all time units within the fourth time range.
  • the processing unit 702 when searching for a synchronization signal, is specifically configured to:
  • the synchronization signal of the first terminal When the synchronization signal of the first terminal is searched, the synchronization signal of at least one target class device is searched; wherein, the sequence of the synchronization signal of the at least one target class device is within the set signal sequence range, and each target class The synchronization priority of the device is higher than or equal to the synchronization priority of the first terminal.
  • the processing unit 702 when searching for a synchronization signal, is specifically configured to:
  • the set signal sequence range is the signal sequence range where the sequence of the synchronization signal of at least one target class device is located, and the synchronization priority of each target class device is higher than or equal to the synchronization priority of the first terminal .
  • processing unit 702 may be configured to perform, through the communication unit 701:
  • the synchronization signal is searched according to the target synchronization priority configuration information; wherein, the target synchronization priority configuration information is used to indicate the synchronization priorities of different types of devices;
  • Searching for synchronization signals according to the target synchronization priority configuration information including:
  • the synchronization signal of the first terminal When the synchronization signal of the first terminal is searched, the synchronization signal of at least one target class device is searched; wherein, the sequence of the synchronization signal of the at least one target class device is within the set signal sequence range, and each target class The synchronization priority of the device is higher than or equal to the synchronization priority of the first terminal; or
  • the set signal sequence range is the signal sequence range where the sequence of the synchronization signal of at least one target class device is located, and the synchronization priority of each target class device is higher than or equal to the synchronization priority of the first terminal .
  • An embodiment of the present application further provides a communication apparatus, the communication apparatus includes a unit for performing the steps of the synchronization methods provided in the above embodiments and examples.
  • the structure of the communication apparatus may be the same as that of the terminal 700 shown in FIG. 7 .
  • each functional unit in each embodiment of the present application It can be integrated in one processing unit, or it can exist physically alone, or two or more units can be integrated in one unit.
  • the above-mentioned integrated units may be implemented in the form of hardware, or may be implemented in the form of software functional units.
  • the integrated unit if implemented as a software functional unit and sold or used as a stand-alone product, may be stored in a computer-readable storage medium.
  • the technical solutions of the present application can be embodied in the form of software products in essence, or the parts that contribute to the prior art, or all or part of the technical solutions, and the computer software products are stored in a storage medium , including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) or a processor (processor) to execute all or part of the steps of the methods in the various embodiments of the present application.
  • the aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk and other media that can store program codes .
  • an embodiment of the present application also provides a terminal, which can be applied to the application scenario shown in FIG. 2 .
  • the terminal can implement the methods provided by the above embodiments and examples, and has the functions of the terminal 700 provided by the embodiment shown in FIG. 7 .
  • the terminal 800 includes: a transceiver 801 , a processor 802 , and a memory 803 .
  • the transceiver 801 , the processor 802 and the memory 803 are connected to each other.
  • the transceiver 801 , the processor 802 and the memory 803 are connected to each other through a bus 804 .
  • the bus 804 may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus or the like.
  • PCI peripheral component interconnect
  • EISA extended industry standard architecture
  • the bus can be divided into address bus, data bus, control bus and so on. For ease of presentation, only one thick line is used in FIG. 8, but it does not mean that there is only one bus or one type of bus.
  • the transceiver 801 is used for receiving and sending signals to realize communication with other devices.
  • the transceiver 801 can be connected to an antenna for signal transmission.
  • the processor 802 is configured to implement the synchronization methods provided by the above embodiments or examples. For specific functions, reference may be made to the descriptions in the above embodiments, which will not be repeated here.
  • the processor 802 may be a central processing unit (central processing unit, CPU), a network processor (network processor, NP), or a combination of CPU and NP, and so on.
  • the processor 802 may further include hardware chips.
  • the above-mentioned hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD) or a combination thereof.
  • the above-mentioned PLD can be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a general-purpose array logic (generic array logic, GAL) or any combination thereof.
  • CPLD complex programmable logic device
  • FPGA field-programmable gate array
  • GAL general-purpose array logic
  • the memory 803 is used to store program instructions and the like.
  • the program instructions may include program code, and the program code includes computer operation instructions.
  • the memory 803 may include random access memory (RAM), and may also include non-volatile memory (non-volatile memory), such as at least one disk storage.
  • the processor 802 executes the program instructions stored in the memory 803 to implement the above functions, thereby implementing the methods provided by the above embodiments.
  • Embodiments of the present application further provide a communication device, the communication device has at least one processing element and at least one storage element, wherein the at least one storage element is used to store programs and data, and the at least one processing element is used to execute any The steps of the synchronization method described in an embodiment.
  • the structure of the communication device may be the same as the terminal 800 shown in FIG. 8 .
  • the embodiments of the present application further provide a computer program, when the computer program runs on a computer, the computer can execute the methods provided by the above embodiments.
  • the embodiments of the present application further provide a computer-readable storage medium, where a computer program is stored in the computer-readable storage medium, and when the computer program is executed by a computer, the computer executes the method provided by the above embodiment. .
  • the storage medium may be any available medium that the computer can access.
  • computer readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage media or other magnetic storage devices, or be capable of carrying or storing instructions or data structures in the form of desired program code and any other medium that can be accessed by a computer.
  • an embodiment of the present application further provides a chip, the chip is used to read a computer program stored in a memory, and implement the methods provided by the above embodiments.
  • the embodiments of the present application provide a chip system, where the chip system includes a processor for supporting a computer apparatus to implement the functions involved in the communication device in the above embodiments.
  • the chip system further includes a memory for storing necessary programs and data of the computer device.
  • the chip system may be composed of chips, or may include chips and other discrete devices.
  • the embodiments of the present application provide a synchronization method and device.
  • the synchronization priority of the first type of equipment is the highest, and the synchronization priority of the second type of equipment is higher than or equal to the synchronization priority of the third type of equipment.
  • the third type of equipment is a terminal synchronized to the first type of equipment; the first type of equipment is GNSS, and the second type of equipment is a base station; or the first type of equipment is a base station, and the second type of equipment is GNSS.
  • the terminal to be synchronized may preferentially synchronize to the second type of device under the condition that the terminal to be synchronized cannot be synchronized to the first type of device. Since the second type of equipment is a base station or GNSS, if the terminal to be synchronized is not synchronized to the first type of equipment, it is not necessary to search for the synchronization signal of the second type of equipment through all searches, and when the terminal to be synchronized There is also no need to perform a full search after the device is the sync source. Therefore, the method can significantly reduce the probability that the terminal to be synchronized performs all searches, that is, the chance that the terminal to be synchronized searches for a synchronization signal, thereby reducing the power consumption caused by performing all searches.
  • the terminal device may determine a first time range according to the synchronization information of the current synchronization source, and search for a synchronization signal within the first time range. Since the terminal to be synchronized does not search for synchronization signals outside the first time range, compared with the traditional full search, this implementation can greatly reduce the time for the terminal to be synchronized to perform all searches, thereby significantly reducing the power consumption of the terminal to be synchronized.
  • the embodiments of the present application may be provided as a method, a system, or a computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.
  • computer-usable storage media including, but not limited to, disk storage, CD-ROM, optical storage, etc.
  • These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory result in an article of manufacture comprising instruction means, the instructions
  • the apparatus implements the functions specified in the flow or flow of the flowcharts and/or the block or blocks of the block diagrams.

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Abstract

本申请提供了一种同步方法及设备，在该方法中，待同步终端的目标同步优先级配置信息中第一类设备的同步优先级最高，第二类设备的同步优先级高于或等于第三类设备的同步优先级。第三类设备为同步到第一类设备的终端；第一类设备为GNSS，第二类设备为基站；或者第一类设备为基站，第二类设备为GNSS。这样，待同步终端可以不能同步到第一类设备的情况下优先同步到第二类设备。由于第二类设备为基站或GNSS，因此待同步终端在未同步到第一类设备的情况下，可以无需通过全部搜索来搜索第二类设备的同步信号，并且当待同步终端将第二类设备作为同步源之后也无需执行全部搜索。因此，该方法可以明显降低待同步终端执行搜索同步信号的机会。

Description

一种同步方法及设备
相关申请的交叉引用
本申请要求在2021年03月08日提交中国专利局、申请号为202110250150.8、申请名称为“一种同步方法、终端及网络设备”的中国专利申请的优先权，其全部内容通过引用结合在本申请中；本申请要求在2021年05月24日提交中国专利局、申请号为202110564759.2、申请名称为“一种同步方法及设备”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及通信技术领域，尤其涉及一种同步方法及设备。
背景技术
随着通信技术的发展，自第三代合作伙伴计划(3 rd Generation Partnership Project，3GPP)版本(release)12开始，第四代(4 th generation，4G)通信系统(即长期演进(Long Term Evolution，LTE)系统)和第五代(5 th generation，5G)通信系统(即新无线(new radio，NR)系统)均可以支持设备和设备之间的通信。这种通信方式称为侧行链路(sidelink)通信，两个终端之间建立的连接为直连链路。
在sidelink通信系统中，由于两个终端之间可以直接发送数据，无需在经过基站、核心网等，因此可以大大减少数据传输时延。sidelink通信的一种应用场景为车到任何物体(vehicle to everything，V2X)，V2X主要用于实现车与车、路侧基础设施(infrastructure)、行人(pedestrian)、网络(network)等之间的通信。3GPP在release14和release15期间，在LTE系统中引入了对V2X服务的支持，以便将3GPP平台扩展到汽车行业；在release16期间研究了NR V2X的相关设计。
在sidelink通信系统中，为了保证数据传输效率、避免信号碰撞，首要的流程即同步。目前，终端需要按照预设的同步方式进行同步：例如基于全球导航卫星系统(global navigation satellite system，GNSS)同步，或基于基站(gNB/eNB)同步。每种同步方式还规定不同种类设备的同步优先级，例如，在基于GNSS同步的方式中，GNSS的同步优先级最高；在基于基站同步的方式中，基站的同步优先级最高。配置为某个同步方式的需要同步的终端(以下简称为待同步终端)优先与该同步方式中的高同步优先级的设备进行同步。
由于GNSS或基站的同步信号所使用的资源是设定的，待同步终端可以预先确定；而其他类型的设备(一般为直接或间接同步到GNSS或基站的终端)所使用的资源是由自身的配置确定的，待同步终端无法预先确定。因此，待同步终端可以在预先确定的固定资源上搜索GNSS或基站的同步信号，但是若待同步终端未搜索到GNSS或基站的同步信号，那么待同步终端就要同步到同步优先级低于GNSS或基站的其他类型的设备。然而由于待同步终端以及其他类型的设备的移动性，为了保证待同步终端能够持续同步到信号强度最高且优先级更高的其他类型的设备，待同步终端需要在帧内的所有子帧上进行全部搜索(full search，又称为穷搜)，以便可以搜索到所有同步信号。
sidelink通信系统中的待同步终端进行全部搜索，需要其在帧内的所有子帧上搜索同步信号，并且还需要比较搜索到的同步信号的可靠性，这就会对待同步终端造成较高的功耗。
发明内容
本申请提供一种同步方法及设备，用于降低待同步终端执行搜索同步信号的机会或时间，以降低由执行搜索同步信号造成的功耗。
第一方面，本申请实施例提供了一种同步方法，该方法可以应用于sidelink通信系统中的待同步终端中，该方法包括以下步骤：
待同步终端确定目标同步优先级配置信息，所述目标同步优先级配置信息用于表示不同种类的设备的同步优先级；然后所述待同步终端根据所述目标同步优先级配置信息进行同步。其中，在所述目标同步优先级配置信息中，第一类设备的同步优先级最高，第二类设备的同步优先级高于或等于第三类设备的同步优先级，所述第三类设备为同步到所述第一类设备的终端；所述第一类设备为GNSS，所述第二类设备为基站；或者所述第一类设备为基站，所述第二类设备为GNSS。
在本方法中，由于目标同步优先级配置信息中，第二类设备的同步优先级高于或等于第三类设备的同步优先级。这样，待同步终端可以在未搜索到第一类设备的同步信号或者搜索到第一类设备的同步信号的信号质量低于设定阈值时，优先同步到第二类设备，从而待同步终端可以优先选择第二类设备为同步源。由于第二类设备为基站或GNSS，即第二类设备的发送同步信号使用的资源为固定资源，因此待同步终端在未同步到第一类设备的情况下，可以无需通过全部搜索来搜索第二类设备的同步信号，并且当待同步终端将第二类设备作为同步源之后也无需执行全部搜索。因此，相对于传统的同步优先级配置，该方法可以明显降低待同步终端执行搜索同步信号的机会，从而可以降低由执行搜索同步信号导致的功耗。
在一种可能的设计中，根据在所述同步优先级配置信息中，第一类设备的同步优先级、第二类设备的同步优先级，以及第三类设备的同步优先级之间的相对关系的具体情况，在本设计中可以包括以下三种情况：
情况一：所述第一类设备的同步优先级高于所述第二类设备的同步优先级，所述第二类设备的同步优先级高于所述第三类设备的同步优先级；即第一类设备的同步优先级>第二设备的同步优先级>第三类设备的同步优先级。在情况一下，待同步终端可以通过以下步骤，根据所述同步优先级配置信息进行同步：
在未搜索到所述第一类设备的同步信号时，且搜索到所述第二类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
在未搜索到所述第一类设备的同步信号和所述第二类设备的同步信号，且搜索到第三类设备的同步信号时，根据所述第三类设备的同步信号与所述第三类设备进行同步。
情况二：所述第二类设备的同步优先级等于所述第一类设备的同步优先级，所述第一类设备的同步优先级和所述第二类设备的同步优先级高于所述第三类设备的同步优先级；即第一类设备的同步优先级＝第二类设备的同步优先级>第三类设备的同步优先级。在情况二下，待同步终端可以通过以下步骤，根据所述同步优先级配置信息进行同步：
在搜索到所述第一类设备的同步信号时，根据所述第一类设备的同步信号与所述第一类设备进行同步；或者
在搜索到所述第二类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；
或者
在未搜索到所述第一类设备的同步信号和所述第二类设备的同步信号，且搜索到第三类设备的同步信号时，根据所述第三类设备的同步信号与所述第三类设备进行同步。
情况三：所述第二类设备的同步优先级等于所述第三类设备的同步优先级，所述第一类设备的同步优先级高于所述第二类设备的同步优先级和所述第三类设备的同步优先级；即第一类设备的同步优先级>第二类设备的同步优先级＝第三类设备的同步优先级。在情况三下，待同步终端可以通过以下步骤，根据所述同步优先级配置信息进行同步：
在未搜索到所述第一类设备的同步信号，且搜索到所述第二类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
在未搜索到所述第一类设备的同步信号，且搜索到所述第三类设备的同步信号时，根据所述第三类设备的同步信号与所述第三类设备进行同步；或者
在未搜索到所述第一类设备的同步信号，且搜索到所述第二类设备的同步信号和所述第三类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
在未搜索到所述第一类设备的同步信号和所述第二类设备的同步信号，且搜索到第三类设备的同步信号时，根据所述第三类设备的同步信号与所述第三类设备进行同步。
在本设计中，第二类设备的同步优先级高于或等于第三类设备的同步优先级。通过本设计，待同步终端可以在未搜索到第一类设备的同步信号或者搜索到第一类设备的同步信号的信号质量低于设定阈值时，优先同步到第二类设备，从而待同步终端可以优先选择第二类设备为同步源。
在一种可能的设计中，在所述目标同步优先级配置信息中，所述第一类设备的同步优先级高于或等于所述第二类设备的同步优先级，第一类设备的同步优先级高于第三类设备的同步优先级；基于此，待同步终端可以通过以下步骤，根据所述同步优先级配置信息进行同步：
在未搜索到所述第一类设备的同步信号时，且搜索到所述第二类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
在搜索到所述第二类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
在未搜索到所述第一类设备的同步信号，且搜索到所述第二类设备的同步信号和所述第三类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
在未搜索到所述第一类设备的同步信号和所述第二类设备的同步信号，且搜索到所述第三类设备的同步信号时，根据所述第三类设备的同步信号进行同步。
在本设计中，第二类设备的同步优先级高于或等于第三类设备的同步优先级。通过本设计，待同步终端可以在未搜索到第一类设备的同步信号或者搜索到第一类设备的同步信号的信号质量低于设定阈值时，优先同步到第二类设备，从而待同步终端可以优先选择第二类设备为同步源。
在一种可能的设计中，所述待同步终端在根据所述第二类设备的同步信号与所述第二 类设备进行同步之前，还可以确定所述第二类设备的同步优先级高于或等于所述待同步终端的当前同步源的同步优先级；和/或确定所述第二类设备的同步信号的信号质量大于或等于设定阈值。
通过该设计，可以保证所述待同步终端可以尽量同步到高同步优先级、且同步信号可靠性较高的设备，从而保证所述待同步终端时间同步的精确性。
在一种可能的设计中，在根据所述第二类设备的同步信号与所述第二类设备进行同步之后，若出现以下情况，则所述待同步终端会继续调整同步源：
情况一：在未搜索到所述第二类设备的同步信号，或者搜索到的所述第二类设备的同步信号的信号质量低于设定阈值时，不再根据所述第二类设备的同步信号与所述第二类设备进行同步；
情况二：在搜索到所述第一类设备的同步信号时，根据所述第一类设备的同步信号与所述第一类设备进行同步。
通过本设计，待同步终端可以根据第二类设备的同步信号的实时变化，及时调整同步源，以保证待同步终端可以尽量同步到同步优先级高，且同步信号可靠的设备。
在一种可能的设计中，考虑到TDD基站的同步源为GNSS，因此，当待同步终端检测到TDD基站的同步信号或者检测到同步到TDD基站的终端的同步信号时，表示当前应用场景中存在GNSS。因此，在本设计中，所述待同步终端在确定目标同步优先级配置信息之前，还可以先执行搜索到目标终端的同步信号，其中，所述目标终端为同步到时分双工TDD通信模式的基站的终端，或所述目标终端位于TDD通信模式的基站的覆盖范围内；或者搜索到所述第二类设备的同步信号。
通过该设计，所述待同步终端搜索到目标终端的同步信号时，表示当前应用场景中存在GNSS。因此，待同步终端可以使用目标同步优先级配置信息，从而可以实现上述方法。
在一种可能的设计中，考虑到TDD基站与GNSS的关系，当所述第一类设备为GNSS时，所述第二类设备为TDD通信模式的基站。
在一种可能的设计中，待同步终端可以通过以下步骤，根据所述目标同步优先级配置信息进行同步：
当所述待同步终端的当前同步源为所述第三类设备或第四类设备时，根据所述当前同步源的同步信息，确定第一时间范围；其中，所述第四类设备为同步到所述第三类设备的终端；在所述第一时间范围内搜索同步信号。
其中，所述第一时间范围又可以称为搜索时间范围，为待同步终端执行搜索的时间范围。换句话说，第一时间范围是用于待同步终端搜索与当前同步源相关的其他终端的同步信号的时间范围。
通过本设计，所述待同步终端在所述第一时间范围以外不搜索同步信号，因此，相对于传统的全部搜索，该实现方式可以大大减少待同步终端执行全部搜索的时间，从而可以明显减低待同步终端的功耗。
还需要说明的是，本实现方式中，所述待同步终端在所述第一时间范围内执行所述搜索同步信号过程中，可以在所述第一时间范围内的全部时间单元执行搜索，或者在所述第一时间范围内的部分时间单元(子帧或时隙)内执行搜索，本申请对此不作限定。可选的，另外，执行搜索的该部分时间单元的时域位置可以为连续的，也可以为离散的，本申请对此也不做限定。
在一种可能的设计中，所述当前同步源的同步信息包含同步信号时域信息，所述同步信号时域信息用于指示第一时长，所述第一时长为所述当前同步源发送的同步信号的时长。在本设计中，所述待同步终端可以通过根据所述同步信号时域信息，确定所述第一时间范围。
由于与同一基站/GNSS相关的终端发送同步信号的时间较为接近，因此，待同步终端可以根据当前同步源的第一时长，确定第一时间范围，以便在第一时间范围内可以搜索到与当前同步源相关的其他终端的同步信号。
在第一种可能的设计中，所述同步信号时域信息为协议规定的，或者为所述待同步终端所接入的基站配置的，或者为所述当前同步源配置的。
在一种可能的设计中，所述第一时间范围的时长大于或等于所述同步信号时域信息所指示的所述第一时长。
由于与同一基站(或GNSS)相关的终端发送同步信号的时间较为接近，但可能存在较小的时间差。因此，在本实现方式中，所述第一时间范围的时长大于或等于所述同步信号时域信息所指示的第一时长。为了尽量多的搜索到与当前同步源相关的其他终端的同步信号，所述第一时间范围的时长可以大于所述同步信号时域信息所指示的第一时长。
在一种可能的设计中，所述第一时间范围的起始位置位于第一时域位置之前，或者等于所述第一时域位置；和/或，所述第一时间范围的结束位置位于第二时域位置之后，或者等于所述第二时域位置；
其中，所述第一时域位置为所述待同步终端搜索到所述当前同步源的同步信号的时域位置；所述第二时域位置位于所述第一时域位置之后，且与所述第一时域位置之间的间隔时长等于所述同步信号时域信息所指示的所述第一时长。
通过该设计，所述待同步终端可以通过搜索到的当前同步源的同步信号的时域位置和第一时长，确定第一时间范围的时域位置。
在一种可能的设计中，所述第一时间范围包含第二时间范围中的部分或全部符号；和/或，所述第一时间范围包含第三时间范围中的部分或全部符号；
其中，所述第二时间范围为在所述第一时间范围的起始位置和所述第一时域位置之间的时间范围，所述第三时间范围为在所述第二时域位置和所述第一时间范围的结束位置之间的时间范围。
在一种可能的设计中，当待同步终端在所述第一时间范围内未搜索到所述第三类设备和所述第四类设备的同步信号(并且也未搜索到第一类设备的同步信号)时，所述待同步终端还可以在第四时间范围(例如搜索时间周期、帧)内的全部时间单元上搜索同步信号，即退回到全部搜索，以便待同步终端可以通过全部搜索，搜索到终端的同步信号实现同步。示例性的，当所述待同步终端在所述第一时间范围内未搜索到任一类设备的同步信号，则在帧内的每个子帧上搜索同步信号。
在一种可能的设计中，所述待同步终端可以通过以下方式，搜索同步信号：
在搜索到第一终端的同步信号时，搜索至少一个目标类的设备的同步信号；其中，所述至少一个目标类的设备的同步信号的序列位于设定的信号序列范围内，每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级，所述第一终端属于所述第三类设备或第四类设备。
通过本设计，在保证待同步终端能够同步到第一终端或者与第一终端的同步优先级相 同或更高的终端的基础上，所述待同步终端可以无需搜索和比对同步优先级低于第一终端其他类终端的同步信号，从而可以降低终端设备的功耗。
在一种可能的设计中，所述待同步终端可以通过以下方式，搜索同步信号：
在搜索到第一终端的同步信号时，搜索位于设定的信号序列范围内的同步信号。其中，所述设定的信号序列范围内的同步信号为至少一个目标类的设备的同步信号。所述每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级。可选的，所述第一终端属于所述第三类设备或第四类设备。而所述至少一个目标类的设备中包含第一类设备和第二类设备。
通过本设计，在保证待同步终端能够同步到第一终端或者与第一终端的同步优先级相同或更高的终端的基础上，所述待同步终端可以无需搜索和比对同步优先级低于第一终端其他类终端的同步信号，从而可以降低终端设备的功耗。
总之，通过以上两种设计，当待同步终端搜索到第一终端的同步信号时，可以确定每个目标类的设备的同步信号的信号序列范围；然后根据每个目标类的设备的同步信号的信号序列范围与接收到的信号进行比对，从而实现相干计算。由于无需比对同步优先级低于第一终端其他类终端的同步信号，从而可以降低终端设备的功耗。
在一种可能的设计中，待同步终端可以通过以下方式，确定目标同步优先级配置信息：
所述待同步终端接收网络设备发送的指示信息(例如图)；其中，所述指示信息用于指示同步方式；然后，所述待同步终端根据所述指示信息所指示的同步方式，在多个同步优先级配置信息中确定所述目标同步优先级配置信息中。
第二方面，本申请实施例提供了一种同步方法，该方法可以应用于sidelink通信系统中的待同步终端中，该方法包括以下步骤：
当所述待同步终端的当前同步源为终端时，待同步终端根据所述当前同步源的同步信息，确定第一时间范围；并在所述第一时间范围内搜索同步信号。
其中，所述第一时间范围又可以称为搜索时间范围，为待同步终端执行搜索的时间范围。换句话说，第一时间范围是用于待同步终端搜索与当前同步源相关的其他终端的同步信号的时间范围。
通过本方法，所述待同步终端在所述第一时间范围以外不搜索同步信号，因此，相对于传统的全部搜索，该实现方式可以大大减少待同步终端执行全部搜索的时间，从而可以明显减低待同步终端的功耗。
还需要说明的是，本方法中，所述待同步终端在所述第一时间范围内执行所述搜索同步信号过程中，可以在所述第一时间范围内的全部时间单元执行搜索，或者在所述第一时间范围内的部分时间单元(子帧或时隙)内执行搜索，本申请对此不作限定。可选的，另外，执行搜索的该部分时间单元的时域位置可以为连续的，也可以为离散的，本申请对此也不做限定。
在一种可能的设计中，所述当前同步源的同步信息包含同步信号时域信息，所述同步信号时域信息用于指示第一时长，所述第一时长为所述当前同步源发送的同步信号的时长；在本设计中，所述待同步终端可以根据所述同步信号时域信息，确定所述第一时间范围。
由于与同一基站/GNSS相关的终端发送同步信号的时间较为接近，因此，待同步终端可以根据当前同步源的第一时长，确定第一时间范围，以便在第一时间范围内可以搜索到与当前同步源相关的其他终端的同步信号。
在一种可能的设计中，所述同步信号时域信息为协议规定的，或者为所述待同步终端所接入的基站配置的，或者为所述当前同步源配置的。
在一种可能的设计中，所述第一时间范围的时长大于或等于所述同步信号时域信息所指示的所述第一时长。
由于与同一基站(或GNSS)相关的终端发送同步信号的时间较为接近，但可能存在较小的时间差。因此，在本实现方式中，所述第一时间范围的时长大于或等于所述同步信号时域信息所指示的第一时长。为了尽量多的搜索到与当前同步源相关的其他终端的同步信号，所述第一时间范围的时长可以大于所述同步信号时域信息所指示的第一时长。
在一种可能的设计中，所述第一时间范围的起始位置位于所述第一时域位置之前，或者等于所述第一时域位置；和/或，所述第一时间范围的结束位置位于第二时域位置之后，或者等于所述第二时域位置；
其中，所述第一时域位置为所述待同步终端搜索到所述当前同步源的同步信号的时域位置；所述第二时域位置位于所述第一时域位置之后，且与所述第一时域位置之间的间隔时长等于所述同步信号时域信息所指示的所述第一时长。
通过该设计，所述待同步终端可以通过搜索到的当前同步源的同步信号的时域位置和第一时长，确定第一时间范围的时域位置。
在一种可能的设计中，所述第一时间范围包含第二时间范围中的部分或全部符号；和/或，所述第一时间范围包含第三时间范围中的部分或全部符号；
其中，所述第二时间范围为在所述第一时间范围的起始位置和所述第一时域位置之间的时间范围，所述第三时间范围为在所述第二时域位置和所述第一时间范围的结束位置之间的时间范围。
在一种可能的设计中，当待同步终端在所述第一时间范围内未搜索到任一类设备的同步信号(并且也未搜索到基站或GNSS的同步信号)时，所述待同步终端还可以在第四时间范围内(例如搜索时间周期、帧)的全部时间单元上搜索同步信号，即退回到全部搜索，以便待同步终端可以通过全部搜索，搜索到终端的同步信号实现同步。
在一种可能的设计中，所述待同步终端可以通过以下方式，搜索同步信号：
在搜索到第一终端的同步信号时，搜索至少一个目标类的设备的同步信号；其中，所述至少一个目标类的设备的同步信号的序列位于设定的信号序列范围内，每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级。
通过本设计，在保证待同步终端能够同步到第一终端或者与第一终端的同步优先级相同或更高的终端的基础上，所述待同步终端可以无需搜索和比对同步优先级低于第一终端其他类终端的同步信号，从而可以降低终端设备的功耗。
在一种可能的设计中，所述待同步终端还可以通过以下方式，搜索同步信号：
在搜索到第一终端的同步信号时，搜索位于设定的信号序列范围内的同步信号。其中，所述设定的信号序列范围内的同步信号为至少一个目标类的设备的同步信号。所述每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级。
通过本设计，在保证待同步终端能够同步到第一终端或者与第一终端的同步优先级相同或更高的终端的基础上，所述待同步终端可以无需搜索和比对同步优先级低于第一终端其他类终端的同步信号，从而可以降低终端设备的功耗。
总之，通过以上两种设计，当待同步终端搜索到第一终端的同步信号时，可以确定每 个目标类的设备的同步信号的信号序列范围；然后根据每个目标类的设备的同步信号的信号序列范围与接收到的信号进行比对，从而实现相干计算。由于无需比对同步优先级低于第一终端其他类终端的同步信号，从而可以降低终端设备的功耗。
第三方面，本申请实施例提供了一种同步方法，该方法可以应用于在sidelink通信系统中的待同步终端，所述方法包括以下步骤：
当所述待同步终端的当前同步源为终端时，按照目标同步优先级配置信息搜索同步信号；其中，所述目标同步优先级配置信息用于表示不同种类的设备的同步优先级；所述待同步终端可以采用以下任一方式，按照所述目标同步优先级配置信息搜索同步信号：
方式一：在搜索到第一终端的同步信号时，搜索至少一个目标类的设备的同步信号。其中，所述至少一个目标类的设备的同步信号的序列位于设定的信号序列范围内，每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级；
方式二：在搜索到第一终端的同步信号时，搜索位于设定的信号序列范围内的同步信号。其中，所述设定的信号序列范围内的同步信号为至少一个目标类的设备的同步信号。所述每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级。
通过本方法，在保证待同步终端能够同步到第一终端或者与第一终端的同步优先级相同或更高的终端的基础上，所述待同步终端可以无需搜索和比对同步优先级低于第一终端其他类终端的同步信号，从而可以降低终端设备的功耗。
总之，通过以上两种设计，当待同步终端搜索到第一终端的同步信号时，可以确定每个目标类的设备的同步信号的信号序列范围；然后根据每个目标类的设备的同步信号的信号序列范围与接收到的信号进行比对，从而实现相干计算。由于无需比对同步优先级低于第一终端其他类终端的同步信号，从而可以降低终端设备的功耗。
第四方面，本申请实施例提供了一种终端，包括用于执行以上第一方面至第三方面中各个步骤的单元。
第五方面，本申请实施例提供了一种终端，包括至少一个处理元件和至少一个存储元件，其中该至少一个存储元件用于存储程序和数据，该至少一个处理元件用于执行本申请以上第一方面至第三方面中提供的方法。
第六方面，本申请实施例提供了一种通信装置，包括用于执行本申请任一实施例所介绍的同步方法的步骤的单元。
第七方面，本申请实施例提供了一种通信设备，包括至少一个处理元件和至少一个存储元件，其中该至少一个存储元件用于存储程序和数据，该至少一个处理元件用于执行本申请任一实施例所介绍的同步方法的步骤。
第八方面，本申请实施例还提供了一种计算机程序，当计算机程序在计算机上运行时，使得计算机执行上述任一方面提供的方法。
第九方面，本申请实施例还提供了一种计算机存储介质，计算机存储介质中存储有计算机程序，当计算机程序被计算机执行时，使得计算机执行上述任一方面提供的方法。
第十方面，本申请实施例还提供了一种芯片，芯片用于读取存储器中存储的计算机程序，执行上述任一方面提供的方法。
第十一方面，本申请实施例还提供了一种芯片系统，该芯片系统包括处理器，用于支持计算机装置实现上述任一方面提供的方法。在一种可能的设计中，芯片系统还包括存储器，存储器用于保存该计算机装置必要的程序和数据。该芯片系统可以由芯片构成，也可 以包含芯片和其他分立器件。
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图1A为一种传统的同步优先级配置示意图；
图1B为一种传统的同步优先级配置示意图；
图1C为一种传统的同步优先级配置示意图；
图2为本申请实施例提供的一种应用场景示意图；
图3为本申请实施例提供的一种同步方法流程图；
图4为本申请实施例提供的一种同步方法流程图；
图5A为本申请实施例提供的一种同步优先级配置信息示意图；
图5B为本申请实施例提供的一种同步优先级配置信息示意图；
图5C为本申请实施例提供的一种同步优先级配置信息示意图；
图5D为本申请实施例提供的一种同步优先级配置信息示意图；
图5E为本申请实施例提供的一种同步优先级配置信息示意图；
图5F为本申请实施例提供的一种同步优先级配置信息示意图；
图5G为本申请实施例提供的一种同步优先级配置信息示意图；
图5H为本申请实施例提供的一种同步优先级配置信息示意图；
图5I为本申请实施例提供的一种同步优先级配置信息示意图；
图6为本申请实施例提供的一种第一时间范围实例示意图；
图7为本申请实施例提供的一种终端的结构图；
图8为本申请实施例提供的另一种终端的结构图。
具体实施方式
本申请提供一种通信方法及设备，用于降低待同步终端执行搜索同步信号的机会或时间，以降低由执行搜索同步信号造成的功耗。其中，方法和设备是基于同一技术构思的，由于方法及设备解决问题的原理相似，因此设备与方法的实施可以相互参见，重复之处不再赘述。
以下，对本申请中的部分用语进行解释说明，以便于本领域技术人员理解。
1)、基站，是移动通信系统中将终端接入到无线网络的设备。基站作为无线接入网中的节点，还可以称为无线接入网(radio access network，RAN)节点(或设备)、网络设备等。
目前，一些基站的举例为：新一代节点B(generation Node B，gNB)、演进型节点B(evolved Node B，eNB)、传输接收点(transmission reception point，TRP)、无线网络控制器(radio network controller，RNC)、节点B(Node B，NB)、接入点(access point，AP)、基站控制器(base station controller，BSC)、基站收发台(base transceiver station，BTS)、家庭基站(例如，home evolved NodeB，或home Node B，HNB)，或基带单元(base band unit，BBU)，在异构网络场景下的微基站、宏基站等。
在一种分布式网络结构中，基站可以包括：基带处理单元(base band unit，BBU)和射频拉远单元(remote radio unit，RRU)。
在云无线接入网(cloud radio access network，CRAN)中，基站可以包括基带池(BBU pool)和RRU。
另外，在一种网络结构中，基站可以包括集中单元(centralized unit，CU)节点和分布单元(distributed unit，DU)节点。这种结构将长期演进(long term evolution，LTE)系统中eNB的协议层拆分开，部分协议层的功能放在CU集中控制，剩下部分或全部协议层的功能分布在DU中，由CU集中控制DU。
2)、终端，是一种向用户提供语音和/或数据连通性的设备。终端又可以称为终端设备、用户设备(user equipment，UE)、移动台(mobile station，MS)、移动终端(mobile terminal，MT)等。
例如，终端可以为具有无线连接功能的手持式设备、各种车载设备、路侧单元等。目前，一些终端的举例为：手机(mobile phone)、平板电脑、笔记本电脑、掌上电脑、移动互联网设备(mobile internet device，MID)、智能销售终端(point of sale，POS)、可穿戴设备，虚拟现实(virtual reality，VR)设备、增强现实(augmented reality，AR)设备、工业控制(industrial control)中的无线终端、无人驾驶(self driving)中的无线终端、远程手术(remote medical surgery)中的无线终端、智能电网(smart grid)中的无线终端、运输安全(transportation safety)中的无线终端、智慧城市(smart city)中的无线终端、智慧家庭(smart home)中的无线终端、各类智能仪表(智能水表、智能电表、智能燃气表)、eLTE-DSA UE、具有接入回传一体化(integrated access and backhaul，IAB)能力的设备、车载电子控制单元(electronic control unit，ECU)等、车载电脑、车载巡航系统、远程信息处理器(telematics box，T-BOX)、车载通信模块、车载用户设备(vehicle UE，VUE)等。
3)、GNSS，泛指所有的卫星导航系统，包括全球的、区域的和增强的各种卫星导航系统。示例性的，GNSS中可以但不限于包括：全球卫星定位系统(global positioning system，GPS)、全球导航卫星系统(global navigation satellite system，GLONASS)、北斗卫星导航系统(beidou navigation satellite system，BDS)、伽利略卫星导航系统(Galileo)等。
其中，GNSS中的通信设备可以简称为GNSS设备或GNSS装置，一般包含GNSS卫星、地面站等。在本申请实施例中，GNSS可以用来指代GNSS设备或GNSS装置等。
4)、设备，即通信设备，为位于通信系统中具有通信功能的设备，在本申请实施例中泛指能够作为终端的同步源，具有发送同步信号的能力的设备。在本申请实施例中，设备可以但不限于包括以下种类：基站、GNSS、终端等。
其中，按照终端的同步源的不同，终端还可以细分为以下几种：
直接同步到基站的终端，可以简称为第一类终端，即同步到基站的终端，或者以基站为同步源的终端。通常，处于基站覆盖范围内(in coverage，IC)的终端，一般会直接同步到基站将基站作为同步源，因此，第一类终端还可以称为IC UE。此外，还需要注意的是，同步到基站，还可以理解为：同步到基站下的小区(cell)，同步到小区等。其中该小区处于基站覆盖范围内。
间接同步到基站的终端，可以简称为第二类终端，即同步到第一类终端的终端，或者以第一类终端为同步源的终端，还可以记为sync with IC UE。
直接同步到GNSS的终端，可以简称为第三类终端，即同步到GNSS的终端，或者以GNSS为同步源的终端，还可以记为GNSS UE。其中，第三类终端的同步源为GNSS，具 体可以为GNSS设备，可以为GNSS卫星或地面站等，本申请对此不作限定。
间接同步到GNSS的终端，可以简称为第四类终端，即同步到第三类终端的终端，或者以第三类终端为同步源的终端，还可以记为sync with GNSS UE。
在以上几种类型中，第一类终端和第二类终端可以统称为与基站相关的终端，第三类终端和第四类终端可以统称为与GNSS相关的终端。
5)、设备的同步优先级，可以理解为：该设备作为同步源时被同步的优先级，或者该设备作为同步源的优先级，终端将该设备作为同步源的优先级，终端使用该设备的同步信号进行同步的优先级。
6)、基站的通信模式，又称为基站管理的小区的通信模式，一般可以包括两种：时分双工(time-division duplex，TDD)和频分双工(frequency-division duplex，FDD)。
其中，TDD通信模式是指，移动通信系统的下行链路(downlink，DL)和上行链路(uplink，UL)共用同一频点，并且为了避免DL和UL之间的信号干扰，移动通信系统采用不同的时间来进行DL通信和UL通信。
FDD通信模式是指，移动通信系统中的DL和UL使用不同的频点。由于FDD通信模式中DL和UL之间信号不会发生干扰，移动通信系统可以同时进行DL通信和UL通信。
TDD通信模式的基站，简称为TDD基站。为了实现全网同步，避免由于与其他TDD基站因为时间不同步造成DL和UL之间的信号干扰，TDD基站通常内部配置有GNSS模块，以接收GNSS同步信号同步到GNSS。
FDD通信模式的基站，简称为FDD基站。由于FDD基站的UL和DL使用不同的频点，即使其无法精确地实现全网同步，也不会影响其通信，因此，FDD基站无需配置GNSS模块。
可选的，为了使接收到同步信号的终端能够识别发射该同步信号的设备为TDD基站或同步到TDD基站的终端，TDD基站或同步到TDD基站的终端可以在同步信号中携带上下行时间配比信息或者TDD指示。其中，所述TDD指示可以指示TDD通信模式中上下行时间配比信息；或者所述TDD指示可以指示发送该同步信号的基站为TDD基站，和/或，发送该同步信号的终端为同步到TDD基站的终端。示例性的，所述上下行时间配比信息或所述TDD指示可以在承载同步信号的广播信道中发送。
这样，终端在接收到该同步信号后，即可根据承载该同步信号的广播信道中的上下行时间配比信息或者TDD指示，确定发送该同步信号的设备为TDD基站或同步到TDD基站的终端。
7)、同步信号(synchronization signal)，用于向待同步设备提供时间参考的参考信号。其中，不同种类的设备发送的同步信号是不同的。同步信号可以承载在广播信道(broadcast channel，BCH)中发送。
例如，基站发送的同步信号为同步信号块(synchronization signal block，SSB)，而GNSS发送的同步信号一般为GNSS信号，例如GPS信号。因此，终端在接收到非SL-SSB的同步信号后，可以通过同步信号的类型(是SSB还是GNSS信号)，来判断该同步信号是由GNSS发送还是由基站发送的。
又例如，在sidelink通信系统中，终端发送的同步信号可以称为侧行链路同步信号(sidelink synchronization signal，SLSS)或者侧行链路同步信号块(sidelink-synchronization signal block，SL-SSB)。在本申请后续描述中，sidelink通信系统中终端发送的同步信号仅 以SL-SSB来表示说明。
SL-SSB的信号序列在规定的信号序列范围内，例如该信号序列范围中包含几百个信号序列。为了便于区分，第三类终端(即直接同步到GNSS的终端)发送的SL-SSB为标号为0的SL-SSB信号序列；而其他类终端(第一类终端、第二类终端、第四类终端)发送的SL-SSB为其他标号的SL-SSB信号序列。
SL-SSB由侧行链路主同步信号(sidelink primary synchronization signal，SPSS)、侧行链路从同步信号(sidelink secondary synchronization signal，SSSS)组成。终端可以通过在SL-SSB中的侧行链路同步信号标识(sidelink synchronization signal identifier，SL-SSID)来标识该SL-SSB为该终端发送的。因此，待同步终端接收到SL-SSB后，可以通过检测SL-SSB中的SL-SSID，来识别发送该SL-SSB的终端。
其中，SL-SSB可以承载在物理侧行链路广播信道(physical sidelink broadcast channel，PSBCH)中发送。SL-SSID可以承载在PSBCH中发送。当然，同步到TDD基站的终端的发送的SL-SSB中，上下行时间配比信息或者TDD指示也可以承载在SL-SSB中的PSBCH中。
另外，终端在SL-SSB周期内可以发送至少一个SL-SSB。示例性的，SL-SSB周期可以为160毫秒(ms)、80ms等。
在本申请实施例中未搜索某类设备的同步信号可以指：未检测到该类设备的同步信号，或者检测到的该类设备的同步信号的信号质量小于设定阈值。相应的，搜索到某类设备的同步信号可以指：检测到该类设备的同步信号，或者检测到的该类设备的同步信号的信号质量大于或等于设定阈值。
8)、搜索时间周期、时间单元、符号，为时间单位。
搜索时间周期，执行全部搜索的时间单位，可以为一个或多个帧(frame)，或者设定时长，本申请对此不作限定。
时间单元，用于组成搜索时间周期的单位。可选的，所述时间单元可以为一个或多个子帧(subframe)、或者为一个或多个时隙(slot)，或者设定时长，本申请对此不作限定。
符号，用于组成时间单元的最小单位，又称为时间符号或时域符号，例如OFDM符号。
9)、“和/或”，描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。字符“/”一般表示前后关联对象是一种“或”的关系。
需要说明的是，本申请中所涉及的多个，是指两个或两个以上。至少一个，是指一个或多个。
另外，需要理解的是，在本申请的描述中，“第一”、“第二”等词汇，仅用于区分描述的目的，而不能理解为指示或暗示相对重要性，也不能理解为指示或暗示顺序。
下面先对目前的同步机制进行说明。
目前，在sidelink通信系统中，同步方式可以通过同步优先级配置参数来确定，所述同步优先级配置参数可以表示为SL-SyncPriority(用于表示设备的同步优先级顺序)。其中，终端的SL-SyncPriority可以为基站动态配置的，或者为终端出厂前配置的。
通过设置SL-SyncPriority的取值，可以表示同步优先级最高的设备为基站或GNSS。
当SL-SyncPriority配置为基站(gNB/eNB)指示信息(例如1)时，表示基站的同步 优先级最高，终端优先同步到基站。
当SL-SyncPriority配置为GNSS指示信息(例如0)时，表示GNSS的同步优先级最高，终端优先同步到GNSS。另外在该同步方式下，还可以通过基站是否为同步源配置参数来指示基站是否能够作为同步源。该基站是否为同步源配置参数可以表示为SL-NbAsSync。
其中，通过设置SL-NbAsSync的取值，可以表示基站是否能够作为同步源。当SL-NbAsSync配置为第一指示信息(例如是(true)、1等)时，表示基站能够作为终端的同步源(或者终端支持将基站作为同步源)；当SL-NbAsSync配置为第二指示信息(例如否(false)、0等)时，表示基站不能作为终端的同步源(或者终端不支持基站作为同步源)。
与SL-SyncPriority类似的，终端的SL-NbAsSync也可以为基站动态配置的，或者为终端出厂前预配置的。
根据终端的SL-SyncPriority以及SL-SyncPriority的配置情况，可以出现以下三种配置过程，如图1A-图1C所示。其中，在图1A-图1C中，Pi代表同步优先级，i的取值越低，代表同步优先级越高，i的取值越高，代表同步优先级越低。P0的同步优先级最高，P1的同步优先级低于P0的同步优先级，但高于P2的同步优先级，以此类推。
情况一：SL-SyncPriority配置为基站(gNB/eNB)指示信息，终端采用优先同步到基站的同步方式。在该情况下，各种设备的同步优先级如图1A所示。
参阅图1A所示，基站的同步优先级最高，即P0：基站。
在本配置过程中，待同步终端优先考虑基站作为同步源。
当待同步终端未搜索到基站的同步信号，或者搜索到的基站的同步信号的信号质量低于设定阈值，那么待同步终端再考虑与基站相关的第一类终端(即P1：直接同步到基站的终端，IC UE)作为同步源。
当待同步终端未搜索第一类终端的同步信号，或者搜索到的第一类终端的同步信号的信号指令低于设定阈值，那么待同步终端再考虑与基站相关的第二类终端(即P2：间接同步到基站的终端，sync with IC UE)作为同步源。
当待同步终端未搜索到第二类终端的同步信号，或者搜索到的第二类终端的同步信号的信号质量低于设定阈值，那么待同步终端再考虑GNSS(即P3：GNSS)作为同步源。
当待同步终端未搜索到GNSS的同步信号，或者搜索到的GNSS的同步信号的信号质量低于设定阈值，那么待同步终端再考虑与GNSS相关的第三类终端(即P4：直接同步到GNSS的终端，GNSS UE)作为同步源。
当待同步终端未搜索到第三类终端的同步信号，或者搜索到的第三类终端的同步信号的信号质量低于设定阈值，那么待同步终端再考虑与GNSS相关的第四类终端(即P5：间接同步到GNSS的终端，sync with GNSS UE)作为同步源。
P6：其他终端，表示当待同步终端未搜索到基站的同步信号、与基站相关的终端的同步信号、GNSS的同步信号，以及与GNSS相关的终端的同步信号，那么该待同步终端自己发送同步信号，作为其他设备的同步源。
情况二：SL-SyncPriority配置为GNSS指示信息，且SL-NbAsSync配置为第一指示信息(例如true)。终端采用优先同步到GNSS的同步方式，且基站能够作为同步源。在该情况下，各种设备的同步优先级如图1B所示。
参阅图1B所示，GNSS的同步优先级最高，即P0：GNSS。
在本配置过程中，待同步终端优先考虑GNSS作为同步源。
在未搜索到GNSS的同步信号，或者搜索到的GNSS的同步信号的信号质量低于设定阈值的情况下，待同步终端后续再依次考虑与GNSS相关的第三类终端(P1：直接同步到GNSS的终端，GNSS UE)、与GNSS相关的第四类终端(P2：间接同步到GNSS的终端，sync with GNSS UE)、基站，以及与基站相关的第一类终端(P4：直接同步到基站的终端，IC UE)、与基站相关的第二类终端(P5：间接同步到基站的终端，sync with IC UE)作为同步源。具体过程与上述情况一相同，此处不再展开赘述。
最后，当待同步终端未搜索到GNSS的同步信号、与GNSS相关的终端的同步信号、基站的同步信号，以及与基站相关的终端的同步信号，那么该待同步终端自己发送同步信号，作为其他设备的同步源。
具体过程可以参考情况一中的过程，此处不再展开赘述。
情况三：SL-SyncPriority配置为GNSS指示信息，且SL-NbAsSync配置为第二指示信息(例如false)。终端采用优先同步到GNSS的同步方式，且基站不能作为同步源。在该情况下，各种设备的同步优先级如图1C所示。
参阅图1C所示，GNSS的同步优先级最高，即P0：GNSS。
在本配置过程中，待同步终端优先考虑GNSS作为同步源。
在未搜索到GNSS的同步信号，或者搜索到的GNSS的同步信号的信号质量低于设定阈值的情况下，待同步终端考虑与GNSS相关的第三类终端(P1：直接同步到GNSS的终端，GNSS UE)、与GNSS相关的第四类终端(P2：间接同步到GNSS的终端，sync with GNSS UE)作为同步源。具体过程与上述情况一类似，此处不再展开赘述。
当待同步终端未搜索到GNSS的同步信号、与GNSS相关的终端的同步信号，那么该待同步终端自己发送同步信号，作为其他设备的同步源。
由于GNSS或基站的同步信号所使用的资源是设定的，待同步终端可以预先确定。与GNSS相关的终端，或者与基站相关的终端所使用的资源是由该终端自身的配置确定的，待同步终端无法预先确定。因此，在以上三种情况下的配置过程中，待同步终端可以在预先确定的固定资源上搜索GNSS或基站的同步信号，但是若待同步终端未搜索到GNSS或基站的同步信号，那么待同步终端就要同步到同步优先级低于GNSS或基站的终端。
然而，由于待同步终端以及当前同步源(与GNSS相关的终端或与基站相关的终端)的移动性，为了保证待同步终端能够持续同步到信号强度最高且优先级更高的终端(与GNSS相关的终端或与基站相关的终端)，待同步终端需要在帧内的所有子帧上进行全部搜索(full search，又称为穷搜)，以便可以搜索到尽量多的终端的同步信号。
sidelink通信系统中的待同步终端进行全部搜索，需要其在帧内的所有子帧上搜索同步信号，并且还需要比较搜索到的同步信号的可靠性，这就会对待同步终端造成较高的功耗。
为了降低由于待同步终端进行全部搜索造成的功耗，本申请实施例提供了一种同步方法。通过该方法，可以降低待同步终端执行搜索同步信号的机会或时间，从而降低由执行搜索同步信号造成的功耗。
下面结合附图对本申请实施例进行具体说明。
图2示出了本申请实施例提供的同步方法适用的应用场景示意图。参阅图2所示，在 该应用场景中包括移动通信系统和GNSS。
在移动通信系统中，包括基站和至少一个终端设备(例如图2中的终端a和终端b)。
基站，是网络侧能够接收和发射无线信号的实体，负责为在其管理的小区内的终端提供无线接入有关的服务，实现物理层功能、资源调度和无线资源管理、服务质量(Quality of Service，QoS)管理、无线接入控制以及移动性管理功能。
移动通信系统中的终端需要通过所述基站接入网络。
在GNSS中，包括GNSS卫星、地面站等GNSS设备，以及至少一个终端(例如图2中的终端c和终端d)。GNSS设备，与移动通信系统中的基站的功能类似的，负责为其覆盖范围内的终端提供无线接入有关的服务，此处不再赘述。GNSS中的终端需要通过所述GNSS设备接入网络。
在图2所示的应用场景中，移动通信系统和GNSS支持sidelink通信技术。sidelink通信技术是一种终端之间能够直连的近场通信技术，又称为近距离服务(proximity services，ProSe)通信技术，或D2D通信技术。在该通信系统中，所处地理位置较近、且支持sidelink通信的多个终端可以组成一个sidelink通信系统(还可以称为sidelink通信子系统，sidelink系统等)。在该sidelink通信系统中，两个终端之间可以通过直连链路进行sidelink通信。例如图2所述，移动通信系统中的终端a和终端b可以组成一个sidelink通信系统，GNSS中的终端c和终端d也可以组成一个sidelink通信系统。
在上述应用场景中，为了保证数据传输效率、避免信号碰撞，终端在接入网络过程中的首要流程即同步。在应用场景中，基站、GNSS、终端均可以广播同步信号以向其他设备提供参考时间。
按照设备的同步源的不同，可以将上述应用场景分为以下几种：
基站，提供同步信号。
直接同步到基站的终端，或者以基站为同步源的终端，简称为：第一类终端、IC UE，例如图中的终端a。
间接同步到基站的终端，或者以直接同步到基站的终端为同步源的终端，简称为：第二类终端、sync with IC UE，例如图中的终端b。
GNSS，提供同步信号。
直接同步到GNSS的终端，或者以GNSS为同步源的终端，简称为：第三类终端、GNSS UE，例如图中的终端c。
间接同步到基站的终端，或者以直接同步到GNSS的终端为同步源的终端，简称为：第四类终端、sync with GNSS UE，例如图中的终端d。
其中，直接同步到基站的终端(第一类终端)、间接同步到基站的终端(第二类终端)还可以统称为与基站相关的终端；直接同步到GNSS的终端(第三类终端)、间接同步到GNSS的终端(第四类终端)还可以统称为与GNSS相关的终端。
需要说明的是，上述六种类型的设备不对应用场景中实际存在的设备的种类构成限定。在实际应用场景中可能存在上述六种类型的设备，或者存在部分类型的设备，本申请实施例对此不作限定。
当然，上述应用系统中的每个终端需要持续搜索同步信号以持续进行同步。另外，由于终端具有移动性，且同步信号的信号质量受多种因素影响，因此终端的同步源会发生变化。以图中的终端e为例，当其移动到基站的覆盖范围内或附近时，可能将基站作为同步 源，或者将第一类终端或第二类终端作为同步源；当其移动到GNSS的覆盖范围内或附近时，可能将GNSS作为同步源，或者将第三类终端或第四类终端作为同步源。
每个终端在进行同步过程中，可以根据同步优先级配置参数(SL-SyncPriority)、以及基站是否为同步源配置参数(SL-NbAsSync)的具体配置情况，按照该配置情况对应的同步优先级配置信息(不同种类的设备的同步优先级，例如图1A-图1C所示)，执行相应的同步配置过程，具体过程可以参考以上对不同情况下的配置过程的描述，此处不再赘述。
还需要指出的是，如图2所示的应用场景作为一个示例，并不对本申请实施例提供的方法适用的场景构成限定。在实际应用中，实际场景可能仅存在移动通信系统，或者仅存在GNSS，或者还存在其他通信系统，本申请实施例对此不作限定。另外，本申请实施例不限定移动通信系统和GNSS的制式。例如，移动通信系统可以为第五代(The 5th Generation，5G)通信系统、长期演进(Long Term Evolution，LTE)通信系统，未来新一代通信系统，或演进的通信系统等，本申请实施例不予限定。
以待同步终端为图2所示的应用场景中的终端e为例，对传统的同步过程进行说明：
当终端e的同步优先级配置参数(SL-SyncPriority)为基站指示信息，终端e的同步优先级配置信息参考图1A。终端e会持续在基站广播的设定资源上搜索基站的同步信号，以便优先同步到基站；当终端e未搜索到基站的同步信号，或搜索到的基站的同步信号的信号质量小于设定阈值时，终端e通过全部搜索，搜索到终端b的同步信号；终端e确定终端b的同步信号的信号质量大于或等于设定阈值时，终端e同步到终端b，将终端b作为当前同步源。
为了保证终端e能够持续同步到信号质量最高且优先级更高的终端，终端e需要在帧内的所有子帧上进行全部搜索，以便可以搜索到第一类终端(例如终端a)的同步信号，从而可以同步到更高同步优先级的设备。
当然，即使同步到终端b，终端e也需要继续在设定资源上搜索基站的同步信号，以便后续可以优先同步到基站。终端e可以并行执行上述全部搜索的过程，以及搜索基站的同步信号的过程。这两个过程不发生冲突。
终端e的同步优先级配置参数(SL-SyncPriority)为GNSS指示信息时的同步配置过程，与上述过程类似，可以相互参考。
通过以上描述可知，传统的同步优先级配置(图1A-图1C)会导致终端执行全部搜索的概率和时间较多，而终端执行全部搜索会导致大量的功耗。因此，如何降低待同步终端执行搜索同步信号的机会或时间，是降低终端功耗的一个重要途径。
为了降低待同步终端进行搜索同步信号造成的功耗，本申请实施例提供了一种同步方法。该方法可以应用于如图2所示的应用场景中支持sidelink通信的待同步终端(例如终端a-终端e)，下面参阅图3所示的流程图，对该方法的步骤进行具体说明。
S301：待同步终端确定目标同步优先级配置信息，所述目标同步优先级配置信息用于表示不同种类的设备的同步优先级。
在一种实施方式中，所述待同步终端可以根据同步优先级配置参数(SL-SyncPriority)，以及基站是否为同步源配置参数(SL-NbAsSync)的具体配置情况，确定所述目标同步优先级配置信息。
例如，当SL-SyncPriority配置为基站指示信息时，所述目标同步优先级配置信息中，基站的同步优先级最高，GNSS的同步优先级高于或等于第一类终端(同步到基站的终端，直接同步到基站的终端)的同步优先级。
又例如，当SL-SyncPriority配置为GNSS指示信息，且SL-NbAsSync配置为第一指示信息(例如是)时，所述目标同步优先级配置信息中，GNSS的同步优先级最高，基站的同步优先级高于或等于第三类终端(同步到GNSS的终端，直接同步到GNSS的终端)的同步优先级。
其中，所述在本实施方式中，同步优先级配置参数(SL-SyncPriority)，以及基站是否为同步源配置参数(SL-NbAsSync)可以为所述待同步终端接入网络设备时，由网络设备配置的，或者为所述待同步终端出厂前预配置的。
在本申请实施例中，所述网络设备可以为待同步终端接入的基站或GNSS。
在另一种实施方式中，所述目标同步优先级配置信息为所述待同步终端接入网络设备时，由网络配置的，或者为待同步终端出厂前预配置的。
在又一种实施方式中，待同步终端设备接收网络设备发送的指示信息，所述指示信息用于指示同步方式；所述待同步终端设备根据所述指示信息所指示的同步方式，在保存的多个同步优先级配置信息中确定所述目标同步优先级配置信息。
可选的，所述指示信息可以包括同步优先级配置参数(SL-SyncPriority)，以及基站是否为同步源配置参数(SL-NbAsSync)；或者所述指示信息通过其它方式指示同步方式，本申请对此不作限定。
其中，所述待同步终端设备保存的多个同步优先级配置信息可以为网络设备配置的，或者为待同步终端出厂前预配置的，本申请对此不作限定。
在待同步终端确定的所述目标同步优先级配置信息中，第一类设备的同步优先级最高，第二类设备的同步优先级高于或等于第三类设备的同步优先级，所述第三类设备为同步到所述第一类设备的终端；所述第一类设备为GNSS，所述第二类设备为基站；或者所述第一类设备为基站，所述第二类设备为GNSS。
根据待同步终端的同步方式的不同，第一类设备至第三类设备所代表的设备类型也不同。
第一种实施方式：当待同步终端的SL-SyncPriority配置为GNSS指示信息，且SL-NbAsSync配置为第一指示信息时，第一类设备为GNSS，第二类设备为基站，第三类设备为第三类终端(即直接同步到GNSS的终端，GNSS UE)。
第二种实施方式：当SL-SyncPriority配置为基站指示信息，第一类设备为基站，第二类设备为GNSS，第三类设备为第一类终端(即直接同步到基站的终端，IC UE)。
S302：待同步终端根据所述目标同步优先级配置信息进行同步。即待同步终端根据所述目标同步优先级配置信息中不同种类的设备的同步优先级进行同步。
第一种实施方式：在所述目标同步优先级配置信息中，所述第一类设备的同步优先级高于或等于所述第二类设备的同步优先级，第一类设备的同步优先级高于第三类设备的同步优先级。在该情况下，待同步终端可以通过以下步骤，执行S302：
在未搜索到所述第一类设备的同步信号时，且搜索到所述第二类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
在搜索到所述第二类设备的同步信号时，根据所述第二类设备的同步信号与所述第二 类设备进行同步；或者
在未搜索到所述第一类设备的同步信号，且搜索到所述第二类设备的同步信号和所述第三类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
在未搜索到所述第一类设备的同步信号和所述第二类设备的同步信号，且搜索到所述第三类设备的同步信号时，根据所述第三类设备的同步信号进行同步。
第二种实施方式：根据在所述同步优先级配置信息中，第一类设备的同步优先级、第二类设备的同步优先级，以及第三类设备的同步优先级之间的相对关系的具体情况，在本实施方式中包括以下三种情况：
情况一：所述第一类设备的同步优先级高于所述第二类设备的同步优先级，所述第二类设备的同步优先级高于所述第三类设备的同步优先级。即第一类设备的同步优先级>第二设备的同步优先级>第三类设备的同步优先级。例如，P0：第一类设备；P1：第二类设备；P2：第三类设备；……
在情况一中，所述待同步终端可以通过以下步骤，执行S302：
在未搜索到所述第一类设备的同步信号时，且搜索到所述第二类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
在未搜索到所述第一类设备的同步信号和所述第二类设备的同步信号，且搜索到第三类设备的同步信号时，根据所述第三类设备的同步信号与所述第三类设备进行同步。
情况二：所述第二类设备的同步优先级等于所述第一类设备的同步优先级，所述第一类设备的同步优先级和所述第二类设备的同步优先级高于所述第三类设备的同步优先级。即第一类设备的同步优先级＝第二类设备的同步优先级>第三类设备的同步优先级。例如，P0：第一类设备、第二类设备；P1：第三类设备……
在情况二中，所述待同步终端可以通过以下步骤，执行S302：
在搜索到所述第一类设备的同步信号时，根据所述第一类设备的同步信号与所述第一类设备进行同步；或者
在搜索到所述第二类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
在未搜索到所述第一类设备的同步信号和所述第二类设备的同步信号，且搜索到第三类设备的同步信号时，根据所述第三类设备的同步信号与所述第三类设备进行同步。
情况三：所述第二类设备的同步优先级等于所述第三类设备的同步优先级，所述第一类设备的同步优先级高于所述第二类设备的同步优先级和所述第三类设备的同步优先级。即第一类设备的同步优先级>第二类设备的同步优先级＝第三类设备的同步优先级。例如，P0：第一类设备；P1：第二类设备、第三类设备……
在情况三中，所述待同步终端可以通过以下步骤，执行S302：
在未搜索到所述第一类设备的同步信号，且搜索到所述第二类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
在未搜索到所述第一类设备的同步信号，且搜索到所述第三类设备的同步信号时，根据所述第三类设备的同步信号与所述第三类设备进行同步；或者
在未搜索到所述第一类设备的同步信号，且搜索到所述第二类设备的同步信号和所述 第三类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
在未搜索到所述第一类设备的同步信号和所述第二类设备的同步信号，且搜索到第三类设备的同步信号时，根据所述第三类设备的同步信号与所述第三类设备进行同步。
通过以上两种实施方式的描述可知，由于目标同步优先级配置信息中，第二类设备的同步优先级高于或等于第三类设备的同步优先级。这样，待同步终端可以在未搜索到第一类设备的同步信号或者搜索到第一类设备的同步信号的信号质量低于设定阈值时，优先同步到第二类设备，从而待同步终端可以优先选择第二类设备为同步源。由于第二类设备为基站或GNSS，即第二类设备的发送同步信号使用的资源为固定资源，因此待同步终端在未同步到第一类设备的情况下，可以无需通过全部搜索来搜索第二类设备的同步信号，并且当待同步终端将第二类设备作为同步源之后也无需执行全部搜索。因此，相对于传统的同步优先级配置，该方法可以明显降低待同步终端执行全部搜索的概率，即降低待同步终端搜索同步信号的机会，从而可以降低由执行搜索同步信号导致的功耗。
可选的，在上述两种实施方式中，在待同步终端根据所述第二类设备的同步信号与所述第二类设备进行同步之前，还可以执行以下步骤：
确定所述第二类设备的同步优先级高于或等于所述待同步终端的当前同步源的同步优先级；和/或，确定所述第二类设备的同步信号的信号质量大于或等于设定阈值。
这样，可以保证所述待同步终端可以尽量同步到高同步优先级、且同步信号可靠性较高的设备，从而保证所述待同步终端时间同步的精确性。
另外，可选的，在上述两种实施方式中，在待同步终端根据所述第二类设备的同步信号与所述第二类设备进行同步之后，若出现以下情况，则所述待同步终端会继续调整同步源：
情况一：在未搜索到所述第二类设备的同步信号，或者搜索到的所述第二类设备的同步信号的信号质量低于设定阈值时，所述待同步终端不再根据所述第二类设备的同步信号与所述第二类设备进行同步。
情况二：在搜索到所述第一类设备的同步信号时，所述待同步终端根据所述第一类设备的同步信号与所述第一类设备进行同步。
通过上述方式，待同步终端可以根据第二类设备的同步信号的实时变化，及时调整同步源，以保证待同步终端可以尽量同步到同步优先级高，且同步信号可靠的设备。
在一些实现方式中，考虑到TDD通信模式的基站为了实现全网同步，避免信号干扰，通常会在内部配置有GNSS模块，以同步到GNSS中。即TDD基站的同步源为GNSS，TDD基站与GNSS的时间相同，因此，当待同步终端检测到TDD基站的同步信号或者检测到同步到TDD基站的终端的同步信号时，表示当前应用场景中存在GNSS。
因此，考虑到上述情况，在本申请实施例中，所述待同步终端执行S301之前，还可以先执行以下步骤：
搜索到目标终端的同步信号，其中，所述目标终端为同步到TDD通信模式的基站的终端(即同步到TDD基站的终端)，或所述目标终端位于TDD通信模式的基站的覆盖范围内。因此，所述目标终端可以记为TDD IC UE。
通过前述内容可知，待同步终端在接收到某个终端的同步信号后，可以通过发送同步 信号的广播信道中是否承载有上下行时间配置信息或者TDD指示，来确定该终端是否为TDD IC UE。
在一些实现方式中，考虑到TDD基站与GNSS的关系，当所述第一类设备为GNSS时，所述第二类设备为TDD通信模式的基站。
在一些实现方式中，在执行S301之前，所述待同步终端还可以通过判断是否搜索到第二类设备的同步信号，来判断是否需要根据该目标同步优先级配置信息进行同步：
当搜索到所述第二类设备的同步信号时，所述待同步终端确定需要该目标同步优先级配置信息进行同步，并开始执行S301-S302中的同步过程；
当未搜索到所述第二类设备的同步信号时，所述待同步终端可以采用传统的同步优先级配置执行同步过程，具体过程可以参考前述相关内容，此处不再赘述。
需要说明的是，在本申请实施例中，判断是否搜索到第二类设备的同步信号这一步骤为可选步骤，在实际应用中，待同步终端可以执行该步骤，也可以不执行该步骤，本申请实施例对此不作限定。
在本申请实施例提供的同步方法中，若待同步终端未搜索到第一类设备的同步信号或第二类设备的同步信号，那么待同步终端需要执行全部搜索，以搜索同步优先级较高的终端的同步信号。因此，待同步终端设备在执行S302过程中，可能会存在将第三类设备或第四类设备作为同步源，其中，所述第四类设备为同步到所述第三类设备的终端(即间接同步到第一类设备的终端)。在传统的同步过程中，待同步终端会一直进行全部搜索，以便可以搜索到同步优先级更高、同步信号的信号质量可靠的终端，除非待同步终端搜索到第一类设备或第二类设备的同步信号。因此，降低待同步终端在当前同步源为终端的过程中进行全部搜索的时间，也可以明显降低待同步终端的功耗。
在通信领域中，同步源相同或者同步源相关的设备发送同步信号的时域位置比较接近。在理想状态下，与该基站相关的终端(第一类终端(IC UE)和第二类终端(sync with IC UE))的同步信号发送时间应该相同，但是考虑到不同终端的时延偏差以及覆盖等因素，这些终端之间发送同步时间的时间差较小。类似的，与该GNSS相关的终端(第三类终端(GNSS UE)和第四类终端(sync with GNSS UE))之间发送同步信号的时间差也较小。
综上，在一些实现方式中，当所述待同步终端的当前同步源为终端(例如，所述第三类设备或所述第四类设备)时，所述待同步终端通过以下步骤进行同步：
A1：所述待同步终端根据所述当前同步源的同步信息，确定第一时间范围；
A2：所述待同步终端在所述第一时间范围内搜索同步信号。
其中，所述第一时间范围又可以称为搜索时间范围，为待同步终端执行搜索的时间范围。换句话说，第一时间范围是用于待同步终端搜索与当前同步源相关的其他终端的同步信号的时间范围。
在本申请实施例中，所述当前同步源的同步信息可以为当前同步源的设备类型、所述当前同步源的同步信号时域信息等，本申请对此不作限定。总之，通过所述当前同步源的同步信息，可以确定所述当前同步源发送同步信号的时域位置或同步信号的时长等信息。
通过该实现方式，所述待同步终端在所述第一时间范围以外不搜索同步信号，因此， 相对于传统的全部搜索，该实现方式可以大大减少待同步终端执行全部搜索的时间，从而可以明显减低待同步终端的功耗。
还需要说明的是，本实现方式中，所述待同步终端在所述第一时间范围内执行所述搜索同步信号过程中，可以在所述第一时间范围内的全部时间单元执行搜索，或者在所述第一时间范围内的部分时间单元(子帧或时隙)内执行搜索，本申请对此不作限定。可选的，另外，执行搜索的该部分时间单元的时域位置可以为连续的，也可以为离散的，本申请对此也不做限定。
可选的，所述当前同步源的同步信息包含同步信号时域信息，所述同步信号时域信息用于指示第一时长，所述第一时长为所述当前同步源发送的同步信号的时长。在该情况下，所述待同步终端可以通过以下步骤，执行上述步骤A1：
B1：根据所述同步信号时域信息，确定所述第一时间范围。
其中，所述同步信号时域信息可以为协议规定的，或者为所述待同步终端所接入的基站或GNSS配置的，或者为所述当前同步源配置的(在所述当前同步源出厂前，所述同步信号时域信息可以预配置在所述当前同步源内)，本申请实施例对此不做限定。示例性的，GNSS(或与GNSS相关的终端)的同步信号时域信息为待同步终端出厂前预配置的，或者由协议或管理人员预配置的；而基站(或与基站相关的终端)的同步信号时域信息可以为待同步终端出厂前预配置的，或者由协议或管理人员预配置的，又或者为基站配置的。
其中，所述同步信号时域信息中可以但不限于通过以下方式指示所述第一时长：
方式一：显式指示。所述同步信号时域信息中包含所述第一时长(所述当前同步源发送的同步信号的时长)。
方式二：隐式指示。所述同步信号时域信息中包含：时长指示。所述时长指示与所述第一时长对应。那么待同步终端可以确定与所述时长指示对应的第一时长。
可选的，所述同步信号时域信息中还可以包含以下参数：在同步信号发送周期内同步信号的数量；在同步信号发送周期内首个同步信号的时间偏移；以及当同步信号发送周期内同步信号的数据量大于1时，相邻两个同步信号的时间间隔。通过以上三个参数，可以计算出所述当前同步源发送的每个同步信号的时域位置。
以终端的同步信号为SL-SSB为例，示例性的，所述同步信号时域信息可以表示为SL-SSB的配置时间(SL-SSB-TimeAllocation)。其中，在SL-SSB-TimeAllocation中可以包括以下三个参数：
在SL-SSB周期内SL-SSB的数量，即(SL-NumSSB-WithinPeriod)，用于表示在一个SL-SSB周期内发送SL-SSB的数量。
首个SL-SSB的时间偏移，即(SL-TimeOffsetSSB)，用于表示从SL-SSB周期开始到首个SL-SSB的时域位置之间的时间偏移量。
相邻两个SL-SSB之间的时间间隔，即(SL-TimeInterval)。该参数适用于SL-NumSSB-WithinPeriod大于1的情况。
由于与同一基站(或GNSS)相关的终端发送同步信号的时间较为接近，但可能存在较小的时间差。因此，在本实现方式中，所述第一时间范围的时长大于或等于所述同步信号时域信息所指示的第一时长。为了尽量多的搜索到与当前同步源相关的其他终端的同步信号，所述第一时间范围的时长可以大于所述同步信号时域信息所指示的第一时长。例如：当前同步源为第一类终端/第二类终端，那么与当前同步源相关的其他终端为第一类终端和 第二类终端。又例如：当前同步源为第三类终端/第四类终端，那么与当前同步源相关的其他终端为第三类终端和第四类终端。
另外，所述待同步终端可以通过以下方式，确定所述第一时间范围的时域位置：
所述第一时间范围的起始位置位于第一时域位置之前，或者等于所述第一时域位置；和/或，所述第一时间范围的结束位置位于第二时域位置之后，或者等于所述第二时域位置；
其中，所述第一时域位置为所述待同步终端搜索到所述当前同步源的同步信号的时域位置；所述第二时域位置位于所述第一时域位置之后，且与所述第一时域位置之间的间隔时长等于所述同步信号时域信息所指示的第一时长。
例如，所述第一时间范围的时长大于所述同步信号时域信息所指示的第一时长时，所述第一时间范围的起始位置位于第一时域位置之前，和/或，所述第一时间范围的结束位置位于第二时域位置之后。
另外，所述第一时间范围可以包含第二时间范围中的部分或全部符号；和/或，所述第一时间范围可以包含第三时间范围中的部分或全部符号；其中，所述第二时间范围为在所述第一时间范围的起始位置和所述第一时域位置之间的时间范围，所述第三时间范围为在所述第二时域位置和所述第一时间范围的结束位置之间的时间范围。
可选的，在本申请实施例中，所述第二时间范围可以为一个或多个时间单元，例如1个时隙或2个时隙。所述第三时间范围也可以为一个或多个时间单元，例如1个时隙或2个时隙。
还需要说明的是，若待同步终端在所述第一时间范围内未搜索到任一终端的同步信号(并且也未搜索到第一类设备的同步信号)，则待同步终端在第四时间范围(例如搜索时间周期、帧)内的全部时间单元上搜索同步信号，即退回到全部搜索，以便待同步终端可以通过全部搜索，搜索到终端的同步信号实现同步。示例性的，当所述待同步终端在所述第一时间范围内未搜索到任一类设备的同步信号，则在帧内的每个子帧上搜索同步信号。
在待同步终端的当前同步源为第三类设备或第四类设备的情况下，所述第一时间范围用于搜索第三类设备或第四类设备。因此，当待同步终端在所述第一时间范围内未搜索到第三类设备或第四类设备的同步信号时，退回到全部搜索。
在传统的同步过程中，待同步终端在执行全部搜索过程中，需要搜索所有终端的同步信号，并且还需要比较搜索到的同步信号的可靠性，这也对待同步终端造成较高的功耗。
基于此，在一些实现方式中，待同步终端可以通过以下方法搜索同步信号：
待同步终端在搜索到第一终端的同步信号时(或者在搜索到第一终端的同步信号之后)，继续搜索至少一个目标类的设备的同步信号。其中，所述至少一个目标类的设备的同步信号的序列位于设定的信号序列范围内，每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级。可选的，所述第一终端属于所述第三类设备或第四类设备。在本实施例中，所述至少一个目标类的设备中还可以包含第一类设备和第二类设备中的至少一类。
可选的，所述待同步终端在搜索到第一终端的同步信号，且确定该第一终端的同步信号的信号质量大于设定阈值时，执行本实现方式中的搜索方法。
通过该方法，在保证待同步终端能够同步到第一终端或者与第一终端的同步优先级相同或更高的终端的基础上，所述待同步终端可以无需搜索和比对同步优先级低于第一终端 其他类终端的同步信号，从而可以降低终端设备的功耗。
在另一些实现方式中，待同步终端还可以通过以下方法搜索同步信号：
待同步终端在搜索到第一终端的同步信号时(或者在搜索到第一终端的同步信号之后)，继续搜索位于设定的信号序列范围内的同步信号。其中，所述设定的信号序列范围内的同步信号为至少一个目标类的设备的同步信号。所述每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级。可选的，所述第一终端属于所述第三类设备或第四类设备。而所述至少一个目标类的设备中包含第一类设备和第二类设备。
可选的，所述待同步终端在搜索到第一终端的同步信号，且确定该第一终端的同步信号的信号质量大于设定阈值时，执行本实现方式中的搜索方法。
为了实现以上两种实现方式，通信系统可以对每类终端的同步信号的信号序列设置范围。例如，第一类终端(IC UE)的SL-SSB，第二类终端(sync with IC UE)的SL-SSB，第三类终端(GNSS UE)的SL-SSB，以及第四类终端(sync with GNSS UE)的SL-SSB均分别限定在不同的信号序列范围内。第一类设备和第二类设备(基站和GNSS)的同步信号可以在预设的信号序列范围内。
在上述两种实现方式中，当待同步终端搜索到第一终端的同步信号时，可以确定每个目标类的设备的同步信号的信号序列范围；然后根据每个目标类的设备的同步信号的信号序列范围与接收到的信号进行比对，从而实现相干计算。由于无需比对同步优先级低于第一终端其他类终端的同步信号，从而可以降低终端设备的功耗。
综上，本申请实施例提供了一种同步方法。在该同步方法中，待同步终端的目标同步优先级配置信息中第一类设备的同步优先级最高，第二类设备的同步优先级高于或等于第三类设备的同步优先级。这样，待同步终端可以在未搜索到第一类设备的同步信号或者搜索到第一类设备的同步信号的信号质量低于设定阈值时，优先同步到第二类设备，从而待同步终端可以优先选择第二类设备为同步源。由于第二类设备为基站或GNSS，即第二类设备的发送同步信号使用的资源为固定资源，因此待同步终端在未同步到第一类设备的情况下，可以无需通过全部搜索来搜索第二类设备的同步信号，并且当待同步终端将第二类设备作为同步源之后也无需执行全部搜索。因此，相对于传统的同步优先级配置，该方法可以明显降低待同步终端执行搜索同步信号的概率，从而可以降低由执行搜索同步信号导致的功耗。
为了降低待同步终端执行全部搜索造成的功耗，本申请实施例还提供另一种同步方法。该方法可以应用于如图2所示的应用场景中支持sidelink通信的待同步终端(例如终端a-终端e)。通过以上实施例中的描述可知，当待同步终端的同步源为终端时，待同步终端需要执行全部搜索，以搜索同步优先级较高的终端的同步信号。在传统的同步过程中，待同步终端会一直进行全部搜索，以便可以搜索到同步优先级更高、信号质量超过设定阈值的终端，除非待同步终端搜索到同步优先级最高的基站或GNSS的同步信号，并同步到基站或GNSS。因此，降低待同步终端在当前同步源为终端的过程中进行全部搜索的时间，也可以明显降低待同步终端的功耗。
下面参阅图4所示的流程图，对该方法的步骤进行具体说明。
S401：当所述待同步终端的当前同步源为终端时，所述待同步终端根据所述当前同步源的同步信息，确定第一时间范围。
其中，所述第一时间范围又可以称为搜索时间范围，为待同步终端执行搜索的时间范围。换句话说，第一时间范围是用于待同步终端搜索与当前同步源相关的其他终端的同步信号的时间范围。
在本申请实施例中，所述当前同步源的同步信息可以为当前同步源的设备类型、所述当前同步源的同步信号时域信息等，本申请对此不作限定。总之，通过所述当前同步源的同步信息，可以确定所述当前同步源发送同步信号的时域位置或同步信号的时长等信息。
S402：所述待同步终端在所述第一时间范围内搜索同步信号。
通过本申请实施例提供的同步方法，待同步终端在第一时间范围以外不搜索同步信号，因此，相对于传统的全部搜索，该实现方式可以大大减少待同步终端执行全部搜索的时间，从而可以明显减低待同步终端的功耗。
还需要说明的是，本实施例中，所述待同步终端在所述第一时间范围内执行搜索同步信号过程中，可以在所述第一时间范围内的全部时间单元执行搜索，或者在所述第一时间范围内的部分时间单元(子帧或时隙)内执行搜索，本申请对此不作限定。可选的，另外，执行搜索的该部分时间单元的时域位置可以为连续的，也可以为离散的，本申请对此也不做限定。
在一种实现方式中，所述当前同步源的同步信息包含同步信号时域信息，所述同步信号时域信息用于指示第一时长，所述第一时长为所述当前同步源发送的同步信号的时长。在该情况下，所述待同步终端可以通过以下步骤，执行上述S401：根据所述同步信号时域信息，确定所述第一时间范围。
本实施例中，所述同步信号时域信息的获取方式，所述同步信号时域信息指示所述第一时长的指示方式，以及根据同步信号时域信息确定第一时间范围的过程，均可以参考图3所示的实施例中相应描述，此处不再赘述。
还需要说明的是，若待同步终端在所述第一时间范围内未搜索到任一类设备的同步信号，则待同步终端在第四时间范围(例如搜索时间周期、帧)内的全部时间单元上搜索同步信号，即退回到全部搜索，以便待同步终端可以通过全部搜索，搜索到终端的同步信号实现同步。示例性的，当所述待同步终端在所述第一时间范围内未搜索到任一类设备的同步信号，则在帧内的每个子帧上搜索同步信号。
在传统的同步过程中，待同步终端在执行全部搜索过程中，需要搜索所有终端的同步信号，并且还需要比较搜索到的同步信号的可靠性，这也对待同步终端造成较高的功耗。
基于此，在一些实现方式中，待同步终端可以通过以下方法搜索同步信号：
待同步终端在搜索到第一终端的同步信号时(或者在搜索到第一终端的同步信号之后)，继续搜索至少一个目标类的设备的同步信号。其中，所述至少一个目标类的设备的同步信号的序列位于设定的信号序列范围内，每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级。所述至少一个目标类的设备中可以包含基站和GNSS。
在另一些实现方式中，待同步终端还可以通过以下方法搜索同步信号：
待同步终端在搜索到第一终端的同步信号时(或者在搜索到第一终端的同步信号之后)，继续搜索位于设定的信号序列范围内的同步信号。其中，所述设定的信号序列范围内的同步信号为至少一个目标类的设备的同步信号。所述每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级。
可选的，在以上两种实现方式中，所述待同步终端在搜索到第一终端的同步信号，且 确定该第一终端的同步信号的信号质量大于设定阈值时，再执行上述搜索过程。
通过以上两种实现方式，在保证待同步终端能够同步到第一终端或者与第一终端的同步优先级相同或更高的终端的基础上，所述待同步终端可以无需搜索和比对同步优先级低于第一终端其他类终端的同步信号，从而可以降低终端设备的功耗。
另外，为了实现以上两种实现方式，通信系统可以对每类终端的同步信号的信号序列设置范围。例如，第一类终端(IC UE)的SL-SSB，第二类终端(sync with IC UE)的SL-SSB，第三类终端(GNSS UE)的SL-SSB，以及第四类终端(sync with GNSS UE)均限定在不同的信号序列范围内。而第一类设备和第二类设备(基站和GNSS)的信号序列为固定的。
在上述两种实现方式中，当待同步终端搜索到第一终端的同步信号时，可以确定每个目标类的设备的同步信号的信号序列范围；然后根据每个目标类的设备的同步信号的信号序列范围与接收到的信号进行比对，从而实现相干计算。由于无需比对同步优先级低于第一终端其他类终端的同步信号，从而可以降低终端设备的功耗。
在传统的同步过程中，待同步终端在执行全部搜索过程中，需要搜索所有终端的同步信号，并且还需要比较搜索到的同步信号的可靠性，这也对待同步终端造成较高的功耗。为了降低待同步终端执行全部搜索过程中的功耗，本申请实施例还提供了另一种同步方法。该方法可以应用于图2所示的应用场景中支持sidelink通信的待同步终端(例如终端a-终端e)。
当所述待同步终端的当前同步源为终端时，按照目标同步优先级配置信息搜索同步信号；其中，所述目标同步优先级配置信息用于表示不同种类的设备的同步优先级。其中，所述目标同步优先级配置信息可以为传统的同步优先级配置信息(例如图1A-图1C所示)，还可以为图3所示的实施例中提供的目标同步优先级配置信息，本申请对此不作限定。
在本申请实施例中，所述待同步终端可以通过以下两种实现方式，按照所述目标同步优先级配置信息搜索同步信号：
第一种实现方式：待同步终端在搜索到第一终端的同步信号时(或者在搜索到第一终端的同步信号之后)，继续搜索至少一个目标类的设备的同步信号。其中，所述至少一个目标类的设备的同步信号的序列位于设定的信号序列范围内，每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级。
第二种实现方式：待同步终端在搜索到第一终端的同步信号时(或者在搜索到第一终端的同步信号之后)，继续搜索位于设定的信号序列范围内的同步信号。其中，所述设定的信号序列范围内的同步信号为至少一个目标类的设备的同步信号。所述每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级。所述至少一个目标类的设备中可以包含基站和GNSS。
可选的，在以上两种实现方式中，所述待同步终端在搜索到第一终端的同步信号，且确定该第一终端的同步信号的信号质量大于设定阈值时，再执行上述搜索过程。
通过本申请实施例提供的方法，在保证待同步终端能够同步到第一终端或者与第一终端的同步优先级相同或更高的终端的基础上，所述待同步终端可以无需搜索和比对同步优先级低于第一终端其他类终端的同步信号，从而可以降低待同步设备的功耗。
另外，为了实现以上两种实现方式，通信系统可以对每类终端的同步信号的信号序列设置范围。例如，第一类终端(IC UE)的SL-SSB，第二类终端(sync with IC UE)的SL-SSB， 第三类终端(GNSS UE)的SL-SSB，以及第四类终端(sync with GNSS UE)均限定在不同的信号序列范围内。而第一类设备和第二类设备(基站和GNSS)的信号序列为固定的。
在上述两种实现方式中，当待同步终端搜索到第一终端的同步信号时，可以确定每个目标类的设备的同步信号的信号序列范围；然后根据每个目标类的设备的同步信号的信号序列范围与接收到的信号进行比对，从而实现相干计算。由于无需比对同步优先级低于第一终端其他类终端的同步信号，从而可以降低终端设备的功耗。
还需要说明的是，在本申请各个实施例中，用于判断同步信号的可靠性的设定阈值可以为待同步终端确定的，或者为待同步终端接入网络设备(基站或GNSS)时由网络设备配置的，或者为协议规定的。可选的，所述设定阈值可以参考协议38.331中的信号质量门限值，例如，所述设定阈值可以用于小区选择所用的门限值(Srxlev)等。
基于以上实施例提供的同步方法，本申请还提供了以下实例。下面对各个实例进行说明。
以下实例一至实例三为待同步终端的同步优先级配置参数(SL-SyncPriority)配置为GNSS指示信息，且基站是否为同步源配置参数(SL-NbAsSync)配置为第一指示信息(例如是)的情况下，同步优先级配置信息的实例。
考虑到TDD基站与GNSS的关系，在实例一至实例三中将基站划分为两类：TDD基站和FDD基站。相对于图1B所示传统的同步优先级配置，以下实例一至实例三中，将TDD基站的同步优先级设置为大于或等于第三类终端(直接同步到GNSS的终端，GNSS UE)的同步优先级。
实例一：
相对于图1B所示传统的同步优先级配置，本实例中可以将TDD基站的同步优先级提升到第三类终端(即直接同步到GNSS的终端，GNSS UE)之前，即P1：TDD基站；而FDD基站的同步优先级的顺序保持不变，且第三类终端、第四类终端、FDD基站等其他种类设备的同步优先级依次顺延，顺序保持不变。实例一中不同种类的设备的同步优先级如图5A所示。
在本实例中，在待同步终端根据图5A所示的同步优先级配置信息进行同步过程中：
在未搜索到GNSS的同步信号时，且搜索到TDD基站的同步信号时，根据TDD基站的同步信号与TDD基站进行同步；或者
在未搜索到GNSS的同步信号和TDD基站的同步信号，且搜索到第三类终端(直接同步到GNSS的终端，GNSS UE)的同步信号时，根据第三类终端的同步信号与第三类终端进行同步；
……
按照图5A所示的配置信息中同步优先级从大到小顺序依次考虑将不同种类的设备作为同步源，具体过程可以参考图1A所示的情况一的过程描述。
实例二：
相对于图1B所示传统的同步优先级配置，本实例中可以将TDD基站的同步优先级提升到与GNSS相同，即P0：GNSS或TDD基站；而FDD基站的同步优先级的顺序保持不变，且第三类终端、第四类终端等其他种类设备的同步优先级的顺序也保持不变。实例二 中不同种类的设备的同步优先级如图5B所示。
在本实例中，在待同步终端根据图5B所示的同步优先级配置信息进行同步过程中：
在搜索到GNSS的同步信号时，根据GNSS的同步信号与GNSS进行同步；或者
在搜索到TDD基站的同步信号时，根据TDD基站的同步信号与TDD基站进行同步；或者
在未搜索到GNSS的同步信号和TDD基站的同步信号，且搜索到第三类终端(直接同步到GNSS的终端，GNSS UE)的同步信号时，根据第三类终端的同步信号与第三类终端进行同步；
……
按照图5B所示的配置信息中同步优先级从大到小顺序依次考虑将不同种类的设备作为同步源，具体过程可以参考图1A所示的情况一的过程描述。
实例三：
相对于图1B所示传统的同步优先级配置，本实例中可以将TDD基站的同步优先级提升到与第三类终端相同，即P1：TDD基站或第三类终端；而FDD基站的同步优先级的顺序保持不变，且第四类终端等其他种类设备的同步优先级的顺序也保持不变。实例三中不同种类的设备的同步优先级如图5C所示。
在本实例中，在待同步终端根据图5C所示的同步优先级配置信息进行同步过程中：
在未搜索到GNSS的同步信号，且搜索到TDD基站的同步信号时，根据TDD基站的同步信号与TDD基站进行同步；或者
在未搜索到GNSS的同步信号，且搜索到第三类终端(直接同步到GNSS的终端，GNSS UE)的同步信号时，根据第三类终端的同步信号与第三类终端进行同步；或者
在未搜索到GNSS的同步信号，且搜索到TDD基站的同步信号和第三类终端(直接同步到GNSS的终端，GNSS UE)的同步信号时，根据TDD基站的同步信号与TDD基站进行同步。即待同步终端在同时搜索到TDD基站和第三类终端的同步信号时，优先选择TDD基站进行同步；或者
在未搜索到GNSS的同步信号和TDD基站的同步信号，且搜索到第三类终端(直接同步到GNSS的终端，GNSS UE)的同步信号时，根据第三类终端的同步信号与第三类终端进行同步；
……
按照图5C所示的配置信息中同步优先级从大到小顺序依次考虑将不同种类的设备作为同步源，具体过程可以参考图1A所示的情况一的过程描述。
在一种可能的实现方式中，在上述实例一至实例三中，待同步终端搜索到TDD基站的同步信号，TDD基站的同步信号的信号质量大于或等于设定阈值，且确定所述待同步终端的当前同步源的同步优先级低于所述TDD基站的同步优先级时，待同步终端根据TDD基站的同步信号进行同步，即选择TDD基站作为同步源。
另外，在选择TDD基站作为同步源之后，继续搜索TDD基站的同步信号和GNSS的同步信号，若未搜索到TDD基站的同步信号，或者搜索到的TDD基站的同步信号的信号质量低于设定阈值，或者搜索到GNSS的同步信号超过设定阈值时，待同步终端不再将TDD基站作为同步源。
以下实例四至实例六为待同步终端的同步优先级配置参数(SL-SyncPriority)为基站指示信息的情况下，同步优先级配置信息的实例。
考虑到TDD基站与GNSS的关系，当待同步终端搜索到直接同步到TDD基站的终端(或者在TDD基站的覆盖范围内的终端，TDD IC UE)的同步信号时，表示当前场景中存在GNSS。在该情况下不同种类的设备的同步优先级符合示例四至示例六所示，其中，GNSS的同步优先级设置为大于或等于第一类终端(直接同步到基站的终端，IC UE)的同步优先级。而当待同步终端未搜索到TDD IC UE的同步信号时，待同步终端可以继续采用传统的同步优先级配置，如图1A所示。
实例四：
相对于图1A所示传统的同步优先级配置，本实例中可以将GNSS的同步优先级提升到第一类终端(即直接同步到基站的终端，IC UE)之前，即P1：GNSS；第一类终端、第二类终端等其他种类设备的同步优先级依次顺延，顺序保持不变。实例四中不同种类的设备的同步优先级如图5D所示。
在本实例中，当待同步终端搜索到直接同步到TDD基站的终端(或者在TDD基站的覆盖范围内的终端，TDD IC UE)的同步信号时，待同步终端根据图5D所示的同步优先级配置信息进行同步过程中：
在未搜索到基站的同步信号时，且搜索到GNSS的同步信号时，根据GNSS的同步信号与GNSS进行同步；或者
在未搜索到基站的同步信号和GNSS的同步信号，且搜索到第一类终端(直接同步到基站的终端，IC UE)的同步信号时，根据第一类终端的同步信号与第一类终端进行同步；
……
按照图5D所示的配置信息中同步优先级从大到小顺序依次考虑将不同种类的设备作为同步源，具体过程可以参考图1A所示的情况一的过程描述。
实例五：
相对于图1A所示传统的同步优先级配置，本实例中可以将GNSS的同步优先级提升到与基站相同，即P0：基站或GNSS；第一类终端、第二类终端等其他种类设备的同步优先级依次顺延，顺序保持不变。实例五中不同种类的设备的同步优先级如图5E所示。
在本实例中，当待同步终端搜索到直接同步到TDD基站的终端(或者在TDD基站的覆盖范围内的终端，TDD IC UE)的同步信号时，待同步终端根据图5E所示的同步优先级配置信息进行同步过程中：
在搜索到基站的同步信号时，根据基站的同步信号与基站进行同步；或者
在搜索到GNSS的同步信号时，根据GNSS的同步信号与GNSS进行同步；或者
在未搜索到基站的同步信号和GNSS的同步信号，且搜索到第一类终端(直接同步到基站的终端，IC UE)的同步信号时，根据第一类终端的同步信号与第一类终端进行同步；
……
按照图5E所示的配置信息中同步优先级从大到小顺序依次考虑将不同种类的设备作为同步源，具体过程可以参考图1A所示的情况一的过程描述。
实例六：
相对于图1A所示传统的同步优先级配置，本实例中可以将GNSS的同步优先级提升到与第一类终端相同，即P1：GNSS或第一类终端；第二类终端等其他种类设备的同步优先级依次顺延，顺序保持不变。实例五中不同种类的设备的同步优先级如图5F所示。
在本实例中，当待同步终端搜索到直接同步到TDD基站的终端(或者在TDD基站的覆盖范围内的终端，TDD IC UE)的同步信号时，待同步终端根据图5F所示的同步优先级配置信息进行同步过程中：
在未搜索到基站的同步信号，且搜索到GNSS的同步信号时，根据GNSS的同步信号与GNSS进行同步；或者
在未搜索到基站的同步信号，且搜索到第一类终端(直接同步到基站的终端，IC UE)的同步信号时，根据第一类终端的同步信号与第一类终端进行同步；或者
在未搜索到基站的同步信号，且搜索到GNSS的同步信号和第一类终端(直接同步到基站的终端，IC UE)的同步信号时，根据GNSS的同步信号与GNSS进行同步。即待同步终端在同时搜索到GNSS和第一类终端的同步信号时，优先选择GNSS进行同步；或者
在未搜索到基站的同步信号和GNSS的同步信号，且搜索到第一类终端(直接同步到基站的终端，IC UE)的同步信号时，根据第一类终端的同步信号与第一类终端进行同步；
……
按照图5F所示的配置信息中同步优先级从大到小顺序依次考虑将不同种类的设备作为同步源，具体过程可以参考图1A所示的情况一的过程描述。
在一种可能的实现方式中，在上述实例四至实例六中，待同步终端搜索到GNSS的同步信号，GNSS的同步信号的信号质量大于或等于设定阈值，且确定所述待同步终端的当前同步源的同步优先级低于所述GNSS的同步优先级时，待同步终端根据GNSS的同步信号进行同步，即选择GNSS作为同步源。
另外，在选择GNSS作为同步源之后，继续搜索GNSS的同步信号和基站的同步信号，若未搜索到GNSS的同步信号，或者搜索到的GNSS的同步信号的信号质量低于设定阈值，或者搜索到基站的同步信号超过设定阈值时，待同步终端不再将GNSS作为同步源。
以上实例一至实例六为考虑到TDD基站与GNSS的关系的情况下，各个不同种类的设备的同步优先级配置。以下实例七至实例十二为不考虑TDD基站与GNSS的关系的同步优先级配置信息。
下面实例七至实例九为待同步终端的同步优先级配置参数(SL-SyncPriority)为GNSS指示信息，且基站是否为同步源配置参数(SL-NbAsSync)配置为第一指示信息(例如是)的情况下，同步优先级配置信息的实例。
实例七：相对于图1B所示的传统的同步优先级配置，本实例中可以将基站的同步优先级提高到第三类终端(即直接同步到GNSS的终端，GNSS UE)之前，即P1：基站；而第三类终端、第四类终端的同步优先级依次顺延，顺序保持不变。实例七中不同种类的设备的同步优先级如图5G所示。
在本实例中，在待同步终端根据图5G所示的同步优先级配置信息进行同步过程中：
在未搜索到GNSS的同步信号时，且搜索到基站的同步信号时，根据基站的同步信号与基站进行同步；或者
在未搜索到GNSS的同步信号和基站的同步信号，且搜索到第三类终端(直接同步到GNSS的终端，GNSS UE)的同步信号时，根据第三类终端的同步信号与第三类终端进行同步；
……
按照图5G所示的配置信息中同步优先级从大到小顺序依次考虑将不同种类的设备作为同步源，具体过程可以参考图1A所示的情况一的过程描述。
实例八：相对于图1B所示的传统的同步优先级配置，本实例中可以将基站的同步优先级提高到与GNSS相同，即P0：GNSS或基站；而第三类终端、第四类终端的同步优先级顺序保持不变。实例八中不同种类的设备的同步优先级如图5H所示。
在本实例中，在待同步终端根据图5H所示的同步优先级配置信息进行同步过程中：
在搜索到GNSS的同步信号时，根据GNSS的同步信号与GNSS进行同步；或者
在搜索到基站的同步信号时，根据基站的同步信号与基站进行同步；或者
在未搜索到GNSS的同步信号和基站的同步信号，且搜索到第三类终端(直接同步到GNSS的终端，GNSS UE)的同步信号时，根据第三类终端的同步信号与第三类终端进行同步；
……
按照图5H所示的配置信息中同步优先级从大到小顺序依次考虑将不同种类的设备作为同步源，具体过程可以参考图1A所示的情况一的过程描述。
实例九：相对于图1B所示的传统的同步优先级配置，本实例中可以将基站的同步优先级提高到与第三类终端(即直接同步到GNSS的终端，GNSS UE)相同，即P1：基站或第三类终端；而第四类终端等其他种类设备的同步优先级顺序保持不变。实例九中不同种类的设备的同步优先级如图5I所示。
在本实例中，在待同步终端根据图5I所示的同步优先级配置信息进行同步过程中：
在未搜索到GNSS的同步信号，且搜索到基站的同步信号时，根据基站的同步信号与基站进行同步；或者
在未搜索到GNSS的同步信号，且搜索到第三类终端(直接同步到GNSS的终端，GNSS UE)的同步信号时，根据第三类终端的同步信号与第三类终端进行同步；或者
在未搜索到GNSS的同步信号，且搜索到基站的同步信号和第三类终端(直接同步到GNSS的终端，GNSS UE)的同步信号时，根据基站的同步信号与基站进行同步。即待同步终端在同时搜索到基站和第三类终端的同步信号时，优先选择基站进行同步；或者
在未搜索到GNSS的同步信号和基站的同步信号，且搜索到第三类终端(直接同步到GNSS的终端，GNSS UE)的同步信号时，根据第三类终端的同步信号与第三类终端进行同步；
……
按照图5I所示的配置信息中同步优先级从大到小顺序依次考虑将不同种类的设备作为同步源，具体过程可以参考图1A所示的情况一的过程描述。
在一种可能的实现方式中，在上述实例七至实例九中，待同步终端搜索到基站的同步信号，基站的同步信号的信号质量大于或等于设定阈值，且确定所述待同步终端的当前同 步源的同步优先级低于所述基站的同步优先级时，待同步终端根据基站的同步信号进行同步，即选择基站作为同步源。
另外，在选择基站作为同步源之后，继续搜索基站的同步信号和GNSS的同步信号，若未搜索到基站的同步信号，或者搜索到的基站的同步信号的信号质量低于设定阈值，或者搜索到GNSS的同步信号超过设定阈值时，待同步终端不再将基站作为同步源。
下面实例十至实例十二为待同步终端的同步优先级配置参数(SL-SyncPriority)为基站指示信息的情况下，同步优先级配置信息的实例。
实例十：相对于图1A所示的传统的同步优先级配置，本实例中可以将GNSS的同步优先级提高到第一类终端(即直接同步到基站的终端，IC UE)之前，即P1：GNSS；而第一类终端、第二类终端的同步优先级依次顺延，顺序保持不变。实例十中不同种类的设备的同步优先级如图5D所示。
在本实例中，待同步终端根据图5D所示的同步优先级配置信息进行同步过程中：
在未搜索到基站的同步信号时，且搜索到GNSS的同步信号时，根据GNSS的同步信号与GNSS进行同步；或者
在未搜索到基站的同步信号和GNSS的同步信号，且搜索到第一类终端(直接同步到基站的终端，IC UE)的同步信号时，根据第一类终端的同步信号与第一类终端进行同步；
……
按照图5D所示的配置信息中同步优先级从大到小顺序依次考虑将不同种类的设备作为同步源，具体过程可以参考图1A所示的情况一的过程描述。
实例十一：相对于图1B所示的传统的同步优先级配置，本实例中可以将GNSS的同步优先级提高到与基站相同，即P0：基站或GNSS；而第一类终端、第二类终端的同步优先级顺序保持不变。实例十一中不同种类的设备的同步优先级如图5E所示。
在本实例中，待同步终端根据图5E所示的同步优先级配置信息进行同步过程中：
在搜索到基站的同步信号时，根据基站的同步信号与基站进行同步；或者
在搜索到GNSS的同步信号时，根据GNSS的同步信号与GNSS进行同步；或者
在未搜索到基站的同步信号和GNSS的同步信号，且搜索到第一类终端(直接同步到基站的终端，IC UE)的同步信号时，根据第一类终端的同步信号与第一类终端进行同步；
……
按照图5E所示的配置信息中同步优先级从大到小顺序依次考虑将不同种类的设备作为同步源，具体过程可以参考图1A所示的情况一的过程描述。
实例十二：相对于图1B所示的传统的同步优先级配置，本实例中可以将GNSS的同步优先级提高到与第一类终端(即直接同步到基站的终端，IC UE)相同，即P1：GNSS或第一类终端；而第二类终端等其他种类设备的同步优先级顺序保持不变。实例十二中不同种类的设备的同步优先级如图5F所示。
在本实例中，待同步终端根据图5F所示的同步优先级配置信息进行同步过程中：
在未搜索到基站的同步信号，且搜索到GNSS的同步信号时，根据GNSS的同步信号与GNSS进行同步；或者
在未搜索到基站的同步信号，且搜索到第一类终端(直接同步到基站的终端，IC UE)的同步信号时，根据第一类终端的同步信号与第一类终端进行同步；或者
在未搜索到基站的同步信号，且搜索到GNSS的同步信号和第一类终端(直接同步到基站的终端，IC UE)的同步信号时，根据GNSS的同步信号与GNSS进行同步。即待同步终端在同时搜索到GNSS和第一类终端的同步信号时，优先选择GNSS进行同步；或者
在未搜索到基站的同步信号和GNSS的同步信号，且搜索到第一类终端(直接同步到基站的终端，IC UE)的同步信号时，根据第一类终端的同步信号与第一类终端进行同步；
……
按照图5F所示的配置信息中同步优先级从大到小顺序依次考虑将不同种类的设备作为同步源，具体过程可以参考图1A所示的情况一的过程描述。
在一种可能的实现方式中，在上述实例十至实例十二中，待同步终端搜索到GNSS的同步信号，GNSS的同步信号的信号质量大于或等于设定阈值，且确定所述待同步终端的当前同步源的同步优先级低于所述GNSS的同步优先级时，待同步终端根据GNSS的同步信号进行同步，即选择GNSS作为同步源。
另外，在选择GNSS作为同步源之后，继续搜索GNSS的同步信号和基站的同步信号，若未搜索到GNSS的同步信号，或者搜索到的GNSS的同步信号的信号质量低于设定阈值，或者搜索到基站的同步信号超过设定阈值时，待同步终端不再将GNSS作为同步源。
在以上各个实例中，待同步终端的同步优先级配置信息中，第一类设备的同步优先级最高，第二类设备的同步优先级高于或等于第三类设备的同步优先级；其中，第一类设备为基站时，第二类设备为GNSS；当第一类设备为GNSS时，第二类设备为基站；第三类设备为同步到第一类设备的终端。这样，待同步终端可以在未搜索到第一类设备的同步信号或者搜索到第一类设备的同步信号的信号质量低于设定阈值时，优先同步到第二类设备，从而待同步终端可以优先选择第二类设备为同步源。由于第二类设备为基站或GNSS，即第二类设备的发送同步信号使用的资源为固定资源，因此待同步终端在未同步到第一类设备的情况下，可以无需通过全部搜索来搜索第二类设备的同步信号，并且当待同步终端将第二类设备作为同步源之后也无需执行全部搜索。因此，相对于传统的同步优先级配置，以上各个实例提供的方法可以明显降低待同步终端执行全部搜索的概率，即降低待同步中执行搜索同步信号的机会，从而可以降低由执行搜索同步信号导致的功耗。
以下实例十三至实例十五中为待同步终端的当前同步源为终端，需要执行全部搜索的实例。在实例十三和实例十四中，可以通过设置全部搜索的时间范围——第一时间范围，来降低待同步终端执行全部搜索的时间，从而可以减低待同步终端的功耗。
考虑到同步源相同或者同步源相关的终端发送同步信号的时域位置比较接近，因此，可以根据待同步设备的当前同步源的同步信息确定该第一时间范围，以便待同步终端可以在所述第一时间范围内可以搜索到当前同步源的同步信号，以及与当前同步源相关的其他终端的同步信号。
例如，当前同步源为直接(或间接)同步到目标基站的终端，那么与当前同步源相关的其他终端可以为直接同步到该目标基站的其他终端，以及间接同步到该目标基站的其他终端。
又例如，当前同步源为直接(或间接)同步到目标GNSS的终端，那么与当前同步源相关的其他终端可以为直接同步到该目标GNSS的其他终端，以及间接同步到该目标GNSS的其他终端。
实例十三：待同步终端的同步优先级配置参数(SL-SyncPriority)配置为基站指示信息，那么待同步终端可以采用如图1A所示的传统的同步优先级配置信息进行同步；或者可以根据本申请实施例提供的如图5D、图5E或图5F所示的同步优先级配置信息进行同步。
当待同步终端的当前同步源为第一类终端(直接同步到基站的终端，IC UE)或第二类终端(间接同步到基站的终端，sync with IC UE)时，待同步终端可以根据所述当前同步源的同步信号时域信息(SL-SSB-TimeAllocation)，来确定第一时间范围。然后，所述待同步终端在所述第一时间范围内搜索同步信号。
在本实例中，所述第一时间范围用于所述待同步终端搜索与当前同步源相关的其他终端的同步信号，即第一类终端或第二类终端的同步信号。
具体的，所述待同步终端根据SL-SSB-TimeAllocation，确定第一时长，所述第一时长为所述当前同步源发送的同步信号的时长。然后根据待同步终端搜索到当前同步源的同步信号的时域位置，以及所述第一时长，确定所述第一时间范围。所述第一时间范围可以大于或等于所述第一时长。
例如，所述第一时间范围的起始位置位于第一时域位置之前；且所述第一时间范围的结束位置位于第二时域位置之后。其中，所述第一时域位置为所述待同步终端搜索到所述当前同步源的同步信号的时域位置；所述第二时域位置位于所述第一时域位置之后，且与所述第一时域位置之间的间隔时长等于所述第一时长。可选的，所述第一时间范围可以包括第二时间范围内的部分或全部符号，也可以包括第三时间范围内的部分或全部符号。其中，所述第二时间范围为在所述第一时间范围的起始位置和所述第一时域位置之间的时间范围，所述第三时间范围为在所述第二时域位置和所述第一时间范围的结束位置之间的时间范围。示例性的，第二时间范围可以为1个时隙，第三时间范围可以为1个时隙。
示例性的，待同步终端根据同步信号时域信息所指示的第一时长，确定的第一时间范围可以如图6所示。
在本实例中，所述待同步终端可以在第一时间范围内的部分或全部子帧上执行搜索。并且，所述待同步终端在所述第一时间范围以外不搜索同步信号，因此，相对于传统的全部搜索过程，该实例可以大大减少待同步终端执行全部搜索的时间，从而可以明显减低待同步终端的功耗。
还需要说明的是，若待同步终端在所述第一时间范围内未搜索到任一终端的同步信号，那么为了能够搜索到同步信号，待同步终端可以退回到全部搜索，执行传统的全部搜索过程。
可选的，在本实例中，由于第三类终端(直接同步到GNSS的终端，GNSS UE)和第四类终端(间接同步到GNSS的终端，sync with GNSS UE)与基站不相关，因此第三类终端和第四类终端的同步信号发送位置、与基站相关的终端的同步信号发送位置二者也不相关。因此，在本实例的场景下，若待同步终端的当前同步源为第三类终端或第四终端，那么待同步终端需要继续通过传统的全部搜索过程搜索同步信号。
实例十四：待同步终端的同步优先级配置参数(SL-SyncPriority)配置为GNSS指示信息，且基站是否为同步源配置参数(SL-NbAsSync)配置为第一指示信息(例如是)的情况下，那么待同步终端可以采用如图1B所示的传统的同步优先级配置信息进行同步；或者可以根据本申请实施例提供的如图5A、图5B、图5C，图5G、图5H、图5I所示的同步优先级配置信息进行同步。
当待同步终端的当前同步源为第三类终端(直接同步到GNSS的终端，GNSS UE)或第四类终端(间接同步到GNSS的终端，sync with GNSS UE)时，待同步终端可以根据所述当前同步源的同步信号时域信息(SL-SSB-TimeAllocation)，来确定第一时间范围。然后，所述待同步终端在所述第一时间范围内搜索同步信号。
在本实例中，所述第一时间范围用于所述待同步终端搜索与当前同步源相关的其他终端的同步信号，即第三类终端或第四类终端的同步信号。
所述待同步终端确定第一时间范围的过程可以参考以上实施例中的描述以及实例十三中的描述，此处不再赘述。
在本实例中，所述待同步终端可以在第一时间范围内的部分或全部子帧上执行搜索。并且，所述待同步终端在所述第一时间范围以外不搜索同步信号，因此，相对于传统的全部搜索过程，该实例可以大大减少待同步终端执行全部搜索的时间，从而可以明显减低待同步终端的功耗。
还需要说明的是，若待同步终端在所述第一时间范围内未搜索到任一终端的同步信号，那么为了能够搜索到同步信号，待同步终端可以退回到全部搜索，执行传统的全部搜索过程。
可选的，在本实例中，由于第一类终端(直接同步到基站的终端，IC UE)和第二类终端(间接同步到基站的终端，sync with IC UE)与GNSS不相关，因此第一类终端和第二类终端的同步信号发送位置、与GNSS相关的终端的同步信号的发送位置二者也不相关。因此，在本实例的场景下，若待同步终端的当前同步源为第一类终端或第二终端，那么待同步终端需要继续通过传统的全部搜索过程搜索同步信号。
实例十五：待同步终端的同步优先级配置参数(SL-SyncPriority)配置为GNSS指示信息，且基站是否为同步源配置参数(SL-NbAsSync)配置为第二指示信息(例如否)的情况下，那么待同步终端可以采用如图1C所示的传统的同步优先级配置信息进行同步。
当待同步终端的当前同步源为第三类终端(直接同步到GNSS的终端，GNSS UE)或第四类终端(间接同步到GNSS的终端，sync with GNSS UE)时，待同步终端可以根据所述当前同步源的同步信号时域信息(SL-SSB-TimeAllocation)，来确定第一时间范围。然后，所述待同步终端在所述第一时间范围内搜索同步信号。
在本实例中，所述第一时间范围用于所述待同步终端搜索与当前同步源相关的其他终端的同步信号，即第三类终端或第四类终端的同步信号。
所述待同步终端确定第一时间范围的过程可以参考以上实施例中的描述以及实例十三、实例十四中的描述，此处不再赘述。
在本实例中，所述待同步终端可以在第一时间范围内的部分或全部子帧上执行搜索。并且，所述待同步终端在所述第一时间范围以外不搜索同步信号，因此，相对于传统的全部搜索过程，该实例可以大大减少待同步终端执行全部搜索的时间，从而可以明显减低待 同步终端的功耗。
还需要说明的是，若待同步终端在所述第一时间范围内未搜索到任一终端的同步信号，那么为了能够搜索到同步信号，待同步终端可以退回到全部搜索，执行传统的全部搜索过程。
考虑到待同步终端在搜索同步信号过程中，需要搜索所有终端的同步信号，并且还需要比较搜索到的同步信号的可靠性，这也对待同步终端造成较高的功耗。以下实例十六可以减低待同步终端搜索和比对同步信号的数量，从而可以降低待同步终端的功耗。
实例十六：
待同步终端根据同步优先级配置参数(SL-SyncPriority)(以及基站是否为同步源配置参数(SL-NbAsSync))的配置，根据设定的同步优先级配置信息进行同步。该同步优先级配置信息可以为图1A至图1C所示的传统的同步优先级配置信息，也可以为本申请实施例提供的如图5A至图5I所示的同步优先级配置信息。
待同步终端在搜索同步信号过程中，若搜索到第一终端的同步信号时(或者在搜索到第一终端的同步信号之后)，则继续搜索至少一个目标类的设备的同步信号。其中，所述至少一个目标类的设备的同步信号的序列位于设定的信号序列范围内，每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级。
以待同步终端根据如图1A所示的同步优先级配置信息进行同步为例。
在待同步终端搜索同步信号过程中，若搜索到P1：第一类终端(直接同步到基站的终端，IC UE)的同步信号，那么后续所述待同步终端仅搜索P0：基站，以及P1：第一类终端的同步信号，不再搜索同步优先级为P2-P5的其他设备的同步信号。
基于相同的技术构思，本申请还提供了一种终端，所述终端可以应用于如图2所示的应用场景。所述终端能够实现以上实施例和实例中提供的同步方法，为sidelink通信系统中的待同步终端。参阅图7所示，终端700中包含通信单元701和处理单元702。其中，所述通信单元701用于接收和发送信号。所述通信单元701的物理表现形式可以为收发器和天线等。
在一种实施方式中，所述终端700能够实现如图3所示的同步方法。在本实施方式中，所述处理单元702用于通过所述通信单元701执行：
确定目标同步优先级配置信息，所述目标同步优先级配置信息用于表示不同种类的设备的同步优先级；
根据所述目标同步优先级配置信息进行同步；
其中，在所述目标同步优先级配置信息中，第一类设备的同步优先级最高，第二类设备的同步优先级高于或等于第三类设备的同步优先级，所述第三类设备为同步到所述第一类设备的终端；
所述第一类设备为GNSS，所述第二类设备为基站；或者所述第一类设备为基站，所述第二类设备为GNSS。
可选的，在本实施方式中，所述第一类设备、所述第二类设备和所述第三类设备的同步优先级的相对关系包括以下三种情况：
情况一：在所述目标同步优先级配置信息中，所述第一类设备的同步优先级高于所述 第二类设备的同步优先级，所述第二类设备的同步优先级高于所述第三类设备的同步优先级。在情况一下，所述处理单元702，在根据所述同步优先级配置信息进行同步时，具体用于：
在未搜索到所述第一类设备的同步信号时，且搜索到所述第二类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
在未搜索到所述第一类设备的同步信号和所述第二类设备的同步信号，且搜索到第三类设备的同步信号时，根据所述第三类设备的同步信号与所述第三类设备进行同步。
情况二：在所述目标同步优先级配置信息中，所述第二类设备的同步优先级等于所述第一类设备的同步优先级，所述第一类设备的同步优先级和所述第二类设备的同步优先级高于所述第三类设备的同步优先级。在情况二下，所述处理单元702，在根据所述同步优先级配置信息进行同步时，具体用于：
在搜索到所述第一类设备的同步信号时，根据所述第一类设备的同步信号与所述第一类设备进行同步；或者
在搜索到所述第二类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
在未搜索到所述第一类设备的同步信号和所述第二类设备的同步信号，且搜索到第三类设备的同步信号时，根据所述第三类设备的同步信号与所述第三类设备进行同步。
情况二：在所述目标同步优先级配置信息中，所述第二类设备的同步优先级等于所述第三类设备的同步优先级，所述第一类设备的同步优先级高于所述第二类设备的同步优先级和所述第三类设备的同步优先级。在情况三下，所述处理单元702，在根据所述同步优先级配置信息进行同步时，具体用于：
在未搜索到所述第一类设备的同步信号，且搜索到所述第二类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
在未搜索到所述第一类设备的同步信号，且搜索到所述第三类设备的同步信号时，根据所述第三类设备的同步信号与所述第三类设备进行同步；或者
在未搜索到所述第一类设备的同步信号，且搜索到所述第二类设备的同步信号和所述第三类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
在未搜索到所述第一类设备的同步信号和所述第二类设备的同步信号，且搜索到第三类设备的同步信号时，根据所述第三类设备的同步信号与所述第三类设备进行同步。
可选的，在本实施方式中，在所述目标同步优先级配置信息中，所述第一类设备的同步优先级高于或等于所述第二类设备的同步优先级，第一类设备的同步优先级高于第三类设备的同步优先级。所述处理单元702，在根据所述同步优先级配置信息进行同步时，具体用于：
在未搜索到所述第一类设备的同步信号时，且搜索到所述第二类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
在搜索到所述第二类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
在未搜索到所述第一类设备的同步信号，且搜索到所述第二类设备的同步信号和所述第三类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步。
可选的，所述处理单元702，还用于：
在根据所述第二类设备的同步信号与所述第二类设备进行同步之前，确定所述第二类设备的同步优先级高于或等于所述待同步终端的当前同步源的同步优先级；和/或确定所述第二类设备的同步信号的信号质量大于或等于设定阈值。
可选的，所述处理单元702，还用于：
在根据所述第二类设备的同步信号与所述第二类设备进行同步之后，在未搜索到所述第二类设备的同步信号，或者搜索到的所述第二类设备的同步信号的信号质量低于设定阈值时，不再根据所述第二类设备的同步信号与所述第二类设备进行同步；或者在搜索到所述第一类设备的同步信号时，根据所述第一类设备的同步信号与所述第一类设备进行同步。
可选的，所述处理单元702，还用于：
在确定目标同步优先级配置信息之前，搜索到目标终端的同步信号，其中，所述目标终端为同步到时分双工TDD通信模式的基站的终端，或所述目标终端位于TDD通信模式的基站的覆盖范围内；或者搜索到所述第二类设备的同步信号。
可选的，当所述第一类设备为GNSS时，所述第二类设备为TDD通信模式的基站。
可选的，所述处理单元702，在根据所述目标同步优先级配置信息进行同步时，具体用于：
当所述待同步终端的当前同步源为所述第三类设备或第四类设备时，根据所述当前同步源的同步信息，确定第一时间范围；其中，所述第四类设备为同步到所述第三类设备的终端；
在所述第一时间范围内搜索同步信号。
可选的，所述当前同步源的同步信息包含同步信号时域信息，所述同步信号时域信息用于指示第一时长，所述第一时长为所述当前同步源发送的同步信号的时长。在该情况下，所述处理单元702，在根据所述当前同步源的同步信息，确定第一时间范围时，具体用于：
根据所述同步信号时域信息，确定所述第一时间范围。
可选的，所述同步信号时域信息为协议规定的，或者为所述待同步终端所接入的基站配置的，或者为所述当前同步源配置的。
可选的，所述第一时间范围的时长大于或等于所述同步信号时域信息所指示的所述第一时长。
可选的，所述第一时间范围的起始位置位于第一时域位置之前，或者等于所述第一时域位置；和/或，所述第一时间范围的结束位置位于第二时域位置之后，或者等于所述第二时域位置；
其中，所述第一时域位置为所述待同步终端搜索到所述当前同步源的同步信号的时域位置；所述第二时域位置位于所述第一时域位置之后，且与所述第一时域位置之间的间隔时长等于所述同步信号时域信息所指示的所述第一时长。
可选的，所述第一时间范围包含第二时间范围中的部分或全部符号；和/或，所述第一时间范围包含第三时间范围中的部分或全部符号；
其中，所述第二时间范围为在所述第一时间范围的起始位置和所述第一时域位置之间的时间范围，所述第三时间范围为在所述第二时域位置和所述第一时间范围的结束位置之间的时间范围。
可选的，所述处理单元702，还用于：
在所述第一时间范围内未搜索到所述第三类设备和所述第四类设备的同步信号时，在第四时间范围内的全部时间单元上搜索同步信号。
可选的，所述处理单元702，在搜索同步信号时，具体用于：
在搜索到第一终端的同步信号时，搜索至少一个目标类的设备的同步信号；其中，所述至少一个目标类的设备的同步信号的序列位于设定的信号序列范围内，每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级，所述第一终端属于所述第三类设备或第四类设备。
可选的，所述处理单元702，在搜索同步信号时，具体用于：
在搜索到第一终端的同步信号时，搜索位于设定的信号序列范围内的同步信号；其中，所述设定信号序列范围为至少一个目标类的设备的同步信号的序列所在的信号序列范围，每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级，所述第一终端属于所述第三类设备或第四类设备。
可选的，所述处理单元702，在确定目标同步优先级配置信息时，具体用于：
通过所述通信单元701接收网络设备发送的指示信息；其中，所述指示信息用于指示同步方式；
根据所述指示信息所指示的同步方式，在多个同步优先级配置信息中确定所述目标同步优先级配置信息中。
在一种实施方式中，所述终端700能够实现如图4所示的同步方法。在本实施方式中，所述处理单元702用于通过所述通信单元701执行：
当所述待同步终端的当前同步源为终端时，根据所述当前同步源的同步信息，确定第一时间范围；
在所述第一时间范围内搜索同步信号。
可选的，所述当前同步源的同步信息包含同步信号时域信息，所述同步信号时域信息用于指示第一时长，所述第一时长为所述当前同步源发送的同步信号的时长。在该情况下，所述处理单元702，在根据所述当前同步源的同步信息，确定第一时间范围时，具体用于：
根据所述同步信号时域信息，确定所述第一时间范围。
可选的，所述同步信号时域信息为协议规定的，或者为所述待同步终端所接入的基站配置的，或者为所述当前同步源配置的。
可选的，所述第一时间范围的时长大于或等于所述同步信号时域信息所指示的所述第一时长。
可选的，所述第一时间范围的起始位置位于所述第一时域位置之前，或者等于所述第一时域位置；和/或，所述第一时间范围的结束位置位于第二时域位置之后，或者等于所述第二时域位置；
其中，所述第一时域位置为所述待同步终端搜索到所述当前同步源的同步信号的时域位置；所述第二时域位置位于所述第一时域位置之后，且与所述第一时域位置之间的间隔时长等于所述同步信号时域信息所指示的所述第一时长。
可选的，所述第一时间范围包含第二时间范围中的部分或全部符号；和/或，所述第一时间范围包含第三时间范围中的部分或全部符号；
其中，所述第二时间范围为在所述第一时间范围的起始位置和所述第一时域位置之间 的时间范围，所述第三时间范围为在所述第二时域位置和所述第一时间范围的结束位置之间的时间范围。
可选的，所述处理单元702还用于：
在所述第一时间范围内未搜索到任一类设备的同步信号时，在第四时间范围内的全部时间单元上搜索同步信号。
可选的，所述处理单元702，在搜索同步信号时，具体用于：
在搜索到第一终端的同步信号时，搜索至少一个目标类的设备的同步信号；其中，所述至少一个目标类的设备的同步信号的序列位于设定的信号序列范围内，每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级。
可选的，所述处理单元702，在搜索同步信号时，具体用于：
在搜索到第一终端的同步信号时，搜索位于设定的信号序列范围内的同步信号。其中，所述设定信号序列范围为至少一个目标类的设备的同步信号的序列所在的信号序列范围，每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级。
在一种实施方式中，所述处理单元702可以用于通过所述通信单元701执行：
当所述待同步终端的当前同步源为终端时，按照目标同步优先级配置信息搜索同步信号；其中，所述目标同步优先级配置信息用于表示不同种类的设备的同步优先级；
按照所述目标同步优先级配置信息搜索同步信号，包括：
在搜索到第一终端的同步信号时，搜索至少一个目标类的设备的同步信号；其中，所述至少一个目标类的设备的同步信号的序列位于设定的信号序列范围内，每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级；或者
在搜索到第一终端的同步信号时，搜索位于设定的信号序列范围内的同步信号。其中，所述设定信号序列范围为至少一个目标类的设备的同步信号的序列所在的信号序列范围，每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级。
本申请实施例还提供了一种通信装置，所述通信装置包括用于执行以上实施例和实例提供的同步方法的步骤的单元。示例性的，所述通信装置的结构可以与如图7所示的终端700相同。
需要说明的是，本申请实施例中对模块的划分是示意性的，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是单独物理存在，也可以两个或两个以上单元集成在一个单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。
集成的单元如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的全部或部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)或处理器(processor)执行本申请各个实施例方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、只读存储器(read-only memory，ROM)、随机存取存储器(random access memory，RAM)、磁碟或者光盘等各种可以存储程序代码的介质。
基于相同的技术构思，本申请实施例还提供了一种终端，该终端可以应用于如图2所示的应用场景中。所述终端能够实现以上实施例和实例提供的方法，具有图7所示的实施例提供的终端700的功能。参阅图8所示，终端800包括：收发器801、处理器802，存储器803。其中，收发器801、处理器802以及存储器803之间相互连接。
可选的，收发器801、处理器802以及存储器803之间通过总线804相互连接。总线804可以是外设部件互连标准(peripheral component interconnect，PCI)总线或扩展工业标准结构(extended industry standard architecture，EISA)总线等。总线可以分为地址总线、数据总线、控制总线等。为便于表示，图8中仅用一条粗线表示，但并不表示仅有一根总线或一种类型的总线。
收发器801，用于接收和发送信号，实现与其他设备之间的通信。收发器801可以连接天线以实现信号传输。
处理器802用于实现以上实施例或实例提供的同步方法，具体功能可以参考以上实施例中的描述，此处不再赘述。
其中，处理器802可以是中央处理器(central processing unit，CPU)，网络处理器(network processor，NP)或者CPU和NP的组合等等。处理器802还可以进一步包括硬件芯片。上述硬件芯片可以是专用集成电路(application-specific integrated circuit，ASIC)，可编程逻辑器件(programmable logic device，PLD)或其组合。上述PLD可以是复杂可编程逻辑器件(complex programmable logic device，CPLD)，现场可编程逻辑门阵列(field-programmable gate array，FPGA)，通用阵列逻辑(generic array logic，GAL)或其任意组合。处理器802在实现上述功能时，可以通过硬件实现，当然也可以通过硬件执行相应的软件实现。
存储器803，用于存放程序指令等。具体地，程序指令可以包括程序代码，该程序代码包括计算机操作指令。存储器803可能包含随机存取存储器(random access memory，RAM)，也可能还包括非易失性存储器(non-volatile memory)，例如至少一个磁盘存储器。处理器802执行存储器803所存放的程序指令，实现上述功能，从而实现上述实施例提供的方法。
本申请实施例还提供了一种通信设备，所述通信设备至少一个处理元件和至少一个存储元件，其中该至少一个存储元件用于存储程序和数据，该至少一个处理元件用于执行本申请任一实施例所介绍的同步方法的步骤。示例性的，所述通信设备的结构可以与如图8所示的终端800相同。
基于以上实施例，本申请实施例还提供了一种计算机程序，当所述计算机程序在计算机上运行时，使得所述计算机执行以上实施例提供的方法。
基于以上实施例，本申请实施例还提供了一种计算机可读存储介质，该计算机可读存储介质中存储有计算机程序，所述计算机程序被计算机执行时，使得计算机执行以上实施例提供的方法。
其中，存储介质可以是计算机能够存取的任何可用介质。以此为例但不限于：计算机可读介质可以包括RAM、ROM、EEPROM、CD-ROM或其他光盘存储、磁盘存储介质或者其他磁存储设备、或者能够用于携带或存储具有指令或数据结构形式的期望的程序代码并能够由计算机存取的任何其他介质。
基于以上实施例，本申请实施例还提供了一种芯片，所述芯片用于读取存储器中存储 的计算机程序，实现以上实施例提供的方法。
基于以上实施例，本申请实施例提供了一种芯片系统，该芯片系统包括处理器，用于支持计算机装置实现以上实施例中通信设备所涉及的功能。在一种可能的设计中，所述芯片系统还包括存储器，所述存储器用于保存该计算机装置必要的程序和数据。该芯片系统，可以由芯片构成，也可以包含芯片和其他分立器件。
综上所述，本申请实施例提供了一种同步方法及设备。在该方法中，待同步终端的目标同步优先级配置信息中第一类设备的同步优先级最高，第二类设备的同步优先级高于或等于第三类设备的同步优先级。其中，第三类设备为同步到第一类设备的终端；第一类设备为GNSS，第二类设备为基站；或者第一类设备为基站，第二类设备为GNSS。这样，待同步终端可以不能同步到第一类设备的情况下优先同步到第二类设备。由于第二类设备为基站或GNSS，因此待同步终端在未同步到第一类设备的情况下，可以无需通过全部搜索来搜索第二类设备的同步信号，并且当待同步终端将第二类设备作为同步源之后也无需执行全部搜索。因此，该方法可以明显降低待同步终端执行全部搜索的概率，即降低待同步终端搜索同步信号的机会，从而降低由执行全部搜索造成的功耗。
进一步的，当待同步终端的当前同步源为终端时，终端设备可以根据当前同步源的同步信息，确定第一时间范围，并在该第一时间范围内搜索同步信号。由于待同步终端在第一时间范围以外不搜索同步信号，因此，相对于传统的全部搜索，该实现方式可以大大减少待同步终端执行全部搜索的时间，从而可以明显减低待同步终端的功耗。
本领域内的技术人员应明白，本申请的实施例可提供为方法、系统、或计算机程序产品。因此，本申请可采用完全硬件实施例、完全软件实施例、或结合软件和硬件方面的实施例的形式。而且，本申请可采用在一个或多个其中包含有计算机可用程序代码的计算机可用存储介质(包括但不限于磁盘存储器、CD-ROM、光学存储器等)上实施的计算机程序产品的形式。
本申请是参照根据本申请的方法、设备(系统)、和计算机程序产品的流程图和/或方框图来描述的。应理解可由计算机程序指令实现流程图和/或方框图中的每一流程和/或方框、以及流程图和/或方框图中的流程和/或方框的结合。可提供这些计算机程序指令到通用计算机、专用计算机、嵌入式处理机或其他可编程数据处理设备的处理器以产生一个机器，使得通过计算机或其他可编程数据处理设备的处理器执行的指令产生用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的装置。
这些计算机程序指令也可存储在能引导计算机或其他可编程数据处理设备以特定方式工作的计算机可读存储器中，使得存储在该计算机可读存储器中的指令产生包括指令装置的制造品，该指令装置实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能。
这些计算机程序指令也可装载到计算机或其他可编程数据处理设备上，使得在计算机或其他可编程设备上执行一系列操作步骤以产生计算机实现的处理，从而在计算机或其他可编程设备上执行的指令提供用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的步骤。
显然，本领域的技术人员可以对本申请进行各种改动和变型而不脱离本申请的范围。这样，倘若本申请的这些修改和变型属于本申请权利要求及其等同技术的范围之内，则本申请也意图包含这些改动和变型在内。

Claims (23)

  1. 一种同步方法，应用于侧行链路通信系统中的待同步终端，其特征在于，所述方法包括：
    确定目标同步优先级配置信息，所述目标同步优先级配置信息用于表示不同种类的设备的同步优先级；
    根据所述目标同步优先级配置信息进行同步；
    其中，在所述目标同步优先级配置信息中，第一类设备的同步优先级最高，第二类设备的同步优先级高于或等于第三类设备的同步优先级，所述第三类设备为同步到所述第一类设备的终端；
    所述第一类设备为GNSS，所述第二类设备为基站；或者所述第一类设备为基站，所述第二类设备为GNSS。
  2. 如权利要求1所述的方法，其特征在于，在所述目标同步优先级配置信息中，所述第一类设备的同步优先级高于或等于所述第二类设备的同步优先级，第一类设备的同步优先级高于第三类设备的同步优先级；根据所述同步优先级配置信息进行同步，包括：
    在未搜索到所述第一类设备的同步信号时，且搜索到所述第二类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
    在搜索到所述第二类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步；或者
    在未搜索到所述第一类设备的同步信号，且搜索到所述第二类设备的同步信号和所述第三类设备的同步信号时，根据所述第二类设备的同步信号与所述第二类设备进行同步。
  3. 如权利要求1或2所述的方法，其特征在于，在确定目标同步优先级配置信息之前，所述方法还包括：
    搜索到目标终端的同步信号，其中，所述目标终端为同步到时分双工TDD通信模式的基站的终端，或所述目标终端位于TDD通信模式的基站的覆盖范围内；或者
    搜索到所述第二类设备的同步信号。
  4. 如权利要求1-3任一项所述的方法，其特征在于，当所述第一类设备为GNSS时，所述第二类设备为TDD通信模式的基站。
  5. 如权利要求1-4任一项所述的方法，其特征在于，根据所述目标同步优先级配置信息进行同步，包括：
    当所述待同步终端的当前同步源为所述第三类设备或第四类设备时，根据所述当前同步源的同步信息，确定第一时间范围；其中，所述第四类设备为同步到所述第三类设备的终端；
    在所述第一时间范围内搜索同步信号。
  6. 如权利要求5所述的方法，其特征在于，所述当前同步源的同步信息包含同步信号时域信息，所述同步信号时域信息用于指示第一时长，所述第一时长为所述当前同步源发送的同步信号的时长；
    根据所述当前同步源的同步信息，确定第一时间范围，包括：
    根据所述同步信号时域信息，确定所述第一时间范围。
  7. 如权利要求6所述的方法，其特征在于，所述第一时间范围的起始位置位于第一时 域位置之前，或者等于所述第一时域位置；和/或，
    所述第一时间范围的结束位置位于第二时域位置之后，或者等于所述第二时域位置；
    其中，所述第一时域位置为所述待同步终端搜索到所述当前同步源的同步信号的时域位置；所述第二时域位置位于所述第一时域位置之后，且与所述第一时域位置之间的间隔时长等于所述同步信号时域信息所指示的所述第一时长。
  8. 如权利要求7所述的方法，其特征在于，所述第一时间范围包含第二时间范围中的部分或全部符号；和/或，所述第一时间范围包含第三时间范围中的部分或全部符号；
    其中，所述第二时间范围为在所述第一时间范围的起始位置和所述第一时域位置之间的时间范围，所述第三时间范围为在所述第二时域位置和所述第一时间范围的结束位置之间的时间范围。
  9. 如权利要求5-8任一项所述的方法，其特征在于，所述方法还包括：
    在所述第一时间范围内未搜索到所述第三类设备和所述第四类设备的同步信号时，在第四时间范围内的全部时间单元上搜索同步信号。
  10. 如权利要求5-9任一项所述的方法，其特征在于，搜索同步信号，包括：
    在搜索到第一终端的同步信号时，搜索至少一个目标类的设备的同步信号；其中，每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级，所述第一终端属于所述第三类设备或第四类设备。
  11. 如权利要求5-9任一项所述的方法，其特征在于，搜索同步信号，包括：
    在搜索到第一终端的同步信号时，搜索位于设定的信号序列范围内的同步信号。
  12. 如权利要求1-11任一项所述的方法，其特征在于，确定目标同步优先级配置信息，包括：
    接收网络设备发送的指示信息；其中，所述指示信息用于指示同步方式；
    根据所述指示信息所指示的同步方式，在多个同步优先级配置信息中确定所述目标同步优先级配置信息中。
  13. 一种同步方法，应用于在侧行链路通信系统中的待同步终端，其特征在于，所述方法包括：
    当所述待同步终端的当前同步源为终端时，根据所述当前同步源的同步信息，确定第一时间范围；
    在所述第一时间范围内搜索同步信号。
  14. 如权利要求13所述的方法，其特征在于，所述当前同步源的同步信息包含同步信号时域信息，所述同步信号时域信息用于指示第一时长，所述第一时长为所述当前同步源发送的同步信号的时长；
    根据所述当前同步源的同步信息，确定第一时间范围，包括：
    根据所述同步信号时域信息，确定所述第一时间范围。
  15. 如权利要求14所述的方法，其特征在于，所述第一时间范围的起始位置位于所述第一时域位置之前，或者等于所述第一时域位置；和/或，
    所述第一时间范围的结束位置位于第二时域位置之后，或者等于所述第二时域位置；
    其中，所述第一时域位置为所述待同步终端搜索到所述当前同步源的同步信号的时域位置；所述第二时域位置位于所述第一时域位置之后，且与所述第一时域位置之间的间隔时长等于所述同步信号时域信息所指示的所述第一时长。
  16. 如权利要求15所述的方法，其特征在于，所述第一时间范围包含第二时间范围中的部分或全部符号；和/或，所述第一时间范围包含第三时间范围中的部分或全部符号；
    其中，所述第二时间范围为在所述第一时间范围的起始位置和所述第一时域位置之间的时间范围，所述第三时间范围为在所述第二时域位置和所述第一时间范围的结束位置之间的时间范围。
  17. 如权利要求13-16任一项所述的方法，其特征在于，所述方法还包括：
    在所述第一时间范围内未搜索到任一类设备的同步信号时，在第四时间范围内的全部时间单元上搜索同步信号。
  18. 如权利要求13-17任一项所述的方法，其特征在于，搜索同步信号，包括：
    在搜索到第一终端的同步信号时，搜索至少一个目标类的设备的同步信号；其中，每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级。
  19. 如权利要求13-17任一项所述的方法，其特征在于，搜索同步信号，包括：
    在搜索到第一终端的同步信号时，搜索位于设定的信号序列范围内的同步信号。
  20. 一种同步方法，应用于在侧行链路通信系统中的待同步终端，其特征在于，所述方法包括：
    当所述待同步终端的当前同步源为终端时，按照目标同步优先级配置信息搜索同步信号；其中，所述目标同步优先级配置信息用于表示不同种类的设备的同步优先级；
    按照所述目标同步优先级配置信息搜索同步信号，包括：
    在搜索到第一终端的同步信号时，搜索至少一个目标类的设备的同步信号；其中，所述至少一个目标类的设备的同步信号的序列位于设定的信号序列范围内，每个目标类的设备的同步优先级高于或等于所述第一终端的同步优先级；或者
    在搜索到第一终端的同步信号时，搜索位于设定的信号序列范围内的同步信号。
  21. 一种终端，其特征在于，包括：
    收发器，用于接收和发送信号；
    存储器，用于存储程序指令和数据；
    处理器，用于读取所述存储器中的程序指令和数据，通过所述收发器实现权利要求1-20任一项所述的方法。
  22. 一种计算机可读存储介质，其特征在于，所述计算机可读存储介质中存储有计算机程序，当所述计算机程序在计算机上运行时，使得计算机执行权利要求1-20任一项所述的方法。
  23. 一种芯片，其特征在于，所述芯片与存储器耦合，所述芯片读取存储器中存储的计算机程序，执行权利要求1-20任一项所述的方法。
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