Synchronization method and apparatus

Abstract

A synchronization method and an apparatus, which can be used for implementing synchronization between terminal devices. The method comprises: a first terminal device sends a first sidelink synchronization signal block (S-SSB) that indicates first synchronization information; after receiving the first S-SSB from the first terminal device, a second terminal device sends, on the basis of the signal quality of the first S-SSB, a second S-SSB to the first terminal device, wherein the second S-SSB indicates second synchronization information and indicates that a synchronization source of the second synchronization information is a second synchronization source, and the second synchronization source is one of the following: a global navigation satellite system (GNSS), an access network device, or a terminal device synchronized with the GNSS or the access network device; and after receiving the second S-SSB, the first terminal device updates synchronization information from the first synchronization information to the second synchronization information, each of the first S-SSB and the second S-SSB being a sequence-based SSB.

Description

Synchronization method and device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on August 30, 2023, with application number 202311113429.7 and application name “A Synchronization Method and Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to the field of communications, and in particular to a synchronization method and apparatus. Background Art

[0003] The 3rd Generation Partnership Project (3GPP) is conducting research and standardization on integrated communication and perception. On the sidelink (SL), terminal devices can perform perception using either self-transmitting and self-receiving or self-transmitting and receiving. In the self-transmitting and receiving mode, the transmitter and receiver of the perception signal are the same terminal device. In the self-transmitting and receiving mode, the transmitter and receiver of the perception signal are different terminal devices.

[0004] In the SL communication and perception integration scenario, different types of terminal devices with perception capabilities (referred to as perception terminal devices) can exist. For example, there are terminal devices with both perception and traditional communication capabilities; and there are terminal devices with perception capabilities but without the channel encoding, decoding, and modulation and demodulation capabilities used in traditional communications.

[0005] Typically, sensing terminal devices need to be synchronized to avoid interference.

[0006] Summary of the Invention

[0007] The embodiments of the present application provide a synchronization method and apparatus that can achieve synchronization between terminal devices.

[0008] In the first aspect, a synchronization method is provided, which can be executed by a first terminal device, or by a component of the first terminal device, such as a processor, chip, or chip system of the first terminal device, or by a logic module or software that can realize all or part of the functions of the first terminal device. The method includes: sending a first sidelink synchronization signal block S-SSB, the first S-SSB indicating first synchronization information; receiving a second S-SSB from a second terminal device, the second S-SSB indicating second synchronization information and indicating that the synchronization source of the second synchronization information is a second synchronization source; updating the synchronization information from the first synchronization information to the second synchronization information. The second synchronization source is one of the following: a global navigation satellite system GNSS, an access network device, or a terminal device synchronized with a GNSS or an access network device. The first S-SSB and the second S-SSB are sequence-based SSBs;

[0009] Based on this solution, the first terminal device sends a first S-SSB to indicate the first synchronization information, indicating that the first terminal device has selected a synchronization source. After receiving the sequence-based second S-SSB indicating the second synchronization information, the first terminal device can obtain the second synchronization information. Therefore, the first terminal device can update the synchronization information from the first synchronization information to the second synchronization information. After the first terminal device updates the synchronization information from the first synchronization information to the second synchronization information, it can be considered that the first terminal device and the second terminal device are synchronized, that is, the synchronization between the first terminal device and the second terminal device is achieved, thereby reducing the mutual interference between the first terminal device and the second terminal device.

[0010] In one possible design, the synchronization source of the first synchronization information is the first synchronization source, which is the internal clock of the first terminal device or the third terminal device. The first terminal device and the third terminal device have perception capabilities but do not have channel encoding and decoding and channel modulation and demodulation capabilities.

[0011] In one possible design, the synchronization source of the first synchronization information is the first synchronization source; updating the synchronization information from the first synchronization information to the second synchronization information includes: updating the synchronization information from the first synchronization information to the second synchronization information according to the priority order of the synchronization sources; the priority order of the synchronization sources includes that the priority of the second synchronization source is higher than the priority of the first synchronization source.

[0012] Based on this possible design, the priority of the second synchronization source is higher than that of the first synchronization source, which can ensure that the first terminal device updates the synchronization information from the first synchronization information to the second synchronization information, thereby achieving synchronization between the first terminal device and the second terminal device.

[0013] In one possible design, the second S-SSB includes indication information, where the indication information is used to indicate that the synchronization source of the second synchronization information is the second synchronization source, and the indication information is located in the main information block of the second S-SSB.

[0014] Based on this possible design, the first terminal can quickly learn that the synchronization source of the second synchronization information is the second synchronization source through the indication information, thereby reducing the synchronization delay.

[0015] In one possible design, the second S-SSB includes a sidelink synchronization signal SLSS. When a sequence corresponding to the SLSS is in a preset sequence set, it indicates that the synchronization source of the second synchronization information is the second synchronization source.

[0016] Based on this possible design, the synchronization source of the second synchronization information is implicitly indicated as the second synchronization source through the sequence set in which the sequence corresponding to the SLSS is located, which can reduce signaling overhead.

[0017] In one possible design, the first terminal device has sensing capability but does not have channel coding and decoding and channel modulation and demodulation capabilities. The second terminal device has sensing capability, channel coding and decoding, and channel modulation and demodulation capabilities.

[0018] In a second aspect, a synchronization method is provided, which can be executed by a second terminal device, or by a component of the second terminal device, such as a processor, chip, or chip system of the second terminal device, or by a logic module or software that can realize all or part of the functions of the second terminal device. The method includes: receiving a first sidelink synchronization signal block S-SSB from a first terminal device; and sending a second S-SSB to the first terminal device based on the signal quality of the first S-SSB. The second S-SSB indicates second synchronization information and the synchronization source indicating the second synchronization information is a second synchronization source, and the second synchronization source is one of the following: a global navigation satellite system GNSS, an access network device, or a terminal device synchronized with a GNSS or an access network device. The first S-SSB and the second S-SSB are sequence-based SSBs.

[0019] Based on this solution, after receiving the first sequence-based S-SSB from the first terminal device, the second terminal device sends a second sequence-based S-SSB, and indicates through the second S-SSB that the synchronization source is the second synchronization information of the traditional synchronization source (i.e., the second synchronization source). Since the second S-SSB is a sequence-based S-SSB, the first terminal device can parse the second S-SSB to obtain the second synchronization information and its synchronization source, and then can update the synchronization information to the second synchronization information, thereby achieving synchronization between the first terminal device and the second terminal device.

[0020] In one possible design, a second S-SSB is sent to the first terminal device based on the signal quality of the first S-SSB, including: when the signal quality of the first S-SSB is greater than or equal to a first threshold, sending the second S-SSB to the first terminal device.

[0021] Based on this possible design, when the signal quality of the first S-SSB is greater than or equal to a threshold, it indicates that the distance between the first terminal device and the second terminal device is relatively close, and the interference caused by asynchrony may be large. Therefore, in this case, a second S-SSB based on a sequence is sent to the first terminal device, allowing the first terminal device to synchronize with the second terminal device based on the second S-SSB, thereby reducing mutual interference between the two.

[0022] In one possible design, the second S-SSB includes indication information, where the indication information is used to indicate that the synchronization source of the second synchronization information is the second synchronization source, and the indication information is located in the main information block of the second S-SSB.

[0023] In one possible design, the second S-SSB includes a side link synchronization signal SLSS. When the sequence corresponding to the SLSS is in a preset sequence set, it indicates that the synchronization source of the second synchronization information is the second synchronization source.

[0024] Based on this possible design, the synchronization source of the second synchronization information is implicitly indicated as the second synchronization source through the sequence set in which the sequence corresponding to the SLSS is located, which can reduce signaling overhead.

[0025] In one possible design, before receiving the first S-SSB from the first terminal device, the method also includes: receiving second synchronization information from a second synchronization source; and synchronizing with the second synchronization source based on the second synchronization information.

[0026] In one possible design, the first S-SSB indicates the first synchronization information, the synchronization source of the first synchronization information is the first synchronization source, the first synchronization source is the internal clock of the first terminal device or the third terminal device, the first terminal device and the third terminal device have perception capabilities, but do not have channel encoding and decoding and channel modulation and demodulation capabilities; the priority of the first synchronization source is lower than the priority of the second synchronization source.

[0027] Based on this possible design, the priority of the second synchronization source is higher than that of the first synchronization source, so that when the first terminal device has selected the first synchronization source and receives the second S-SSB, it can update the synchronization source to the second synchronization source based on the priority order, thereby achieving synchronization between the first terminal device and the second terminal device.

[0028] In one possible design, the first terminal device has sensing capability but does not have channel coding and decoding and channel modulation and demodulation capabilities. The second terminal device has sensing capability, channel coding and decoding, and channel modulation and demodulation capabilities.

[0029] In a third aspect, a synchronization method is provided, which is applied to a communication system comprising a first terminal device and a second terminal device. The method comprises: the first terminal device sends a first sidelink synchronization signal block S-SSB, the first S-SSB indicates first synchronization information, and the first S-SSB is a sequence-based SSB; the second terminal device receives the first S-SSB from the first terminal device; the second terminal device also sends a second S-SSB to the first terminal device based on the signal quality of the first S-SSB; wherein the second S-SSB indicates second synchronization information and the synchronization source indicating the second synchronization information is a second synchronization source, and the second synchronization source is one of the following: a global navigation satellite system GNSS, an access network device, or a terminal device synchronized with a GNSS or an access network device; the second S-SSB is a sequence-based SSB; the first terminal device also receives the second S-SSB from the second terminal device, and updates the synchronization information from the first synchronization information to the second synchronization information. The technical effects brought about by the third aspect can refer to the technical effects brought about by the above-mentioned first or second aspects, and will not be repeated here.

[0030] In a fourth aspect, a communication device is provided for implementing various methods. The communication device may be the first terminal device in the first aspect, or a device included in the first terminal device, such as a chip or a chip system; or the communication device may be the second terminal device in the second aspect, or a device included in the second terminal device, such as a chip or a chip system. The communication device includes a module, unit, or means corresponding to the implementation method, which may be implemented by hardware, software, or by executing the corresponding software implementation by hardware. The hardware or software includes one or more modules or units corresponding to the functions.

[0031] In some possible designs, the communication device may include a processing module and a transceiver module. The processing module may be configured to implement the processing functionality of any of the above aspects and any possible implementations thereof. The transceiver module may include a receiving module and a transmitting module, respectively configured to implement the receiving functionality and the transmitting functionality of any of the above aspects and any possible implementations thereof.

[0032] In some possible designs, the transceiver module may be composed of a transceiver circuit, a transceiver, a transceiver or a communication interface.

[0033] In a fifth aspect, a communication device is provided, comprising: a processor and a memory; the memory is configured to store computer instructions, and when the processor executes the instructions, the communication device performs the method described in any aspect. The communication device may be the first terminal device described in the first aspect, or a device included in the first terminal device, such as a chip or a chip system; or the communication device may be the second terminal device described in the second aspect, or a device included in the second terminal device, such as a chip or a chip system.

[0034] In a sixth aspect, a communication device is provided, comprising: a processor and a communication interface; the communication interface is configured to communicate with a module external to the communication device; and the processor is configured to execute a computer program or instruction to cause the communication device to perform the method described in any aspect. The communication device may be the first terminal device described in the first aspect, or a device included in the first terminal device, such as a chip or chip system; or the communication device may be the second terminal device described in the second aspect, or a device included in the second terminal device, such as a chip or chip system.

[0035] In a seventh aspect, a communication device is provided, comprising: at least one processor; the processor is configured to execute a computer program or instruction stored in a memory, so that the communication device performs the method described in any aspect. The memory may be coupled to the processor, or may be independent of the processor. The communication device may be the first terminal device described in the first aspect, or a device included in the first terminal device, such as a chip or chip system; or the communication device may be the second terminal device described in the second aspect, or a device included in the second terminal device, such as a chip or chip system.

[0036] In an eighth aspect, a computer-readable storage medium is provided, in which a computer program or instruction is stored. When the computer-readable storage medium is run on a communication device, the communication device can execute the method described in either the first aspect or the second aspect.

[0037] In a ninth aspect, a computer program product comprising instructions is provided, which, when executed on a communication device, enables the communication device to execute the method described in any one of the first aspect or the second aspect.

[0038] In a tenth aspect, a communication device is provided (for example, the communication device may be a chip or a chip system), which includes a processor for implementing the functions involved in any one of the first aspect or the second aspect.

[0039] In some possible designs, the communication device includes a memory for storing necessary program instructions and data.

[0040] In some possible designs, when the device is a chip system, it can be composed of a chip or include a chip and other discrete devices.

[0041] It can be understood that when the communication device provided in any one of the fourth to tenth aspects is a chip, the sending action / function of the communication device can be understood as output information, and the receiving action / function of the communication device can be understood as input information.

[0042] Among them, the technical effects brought about by any design method in the fourth to tenth aspects can refer to the technical effects brought about by different design methods in the first or second aspects, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG1 is a schematic structural diagram of a traditional S-SSB provided in this application;

[0044] FIG2 is a schematic structural diagram of a sequence-based S-SSB provided in this application;

[0045] FIG3 is a schematic diagram of a synchronization failure scenario provided by the present application;

[0046] FIG4 is a schematic diagram of the structure of a communication system provided by the present application;

[0047] FIG5 is a flow chart of a synchronization method provided by the present application;

[0048] FIG6 is a flow chart of another synchronization method provided by the present application;

[0049] FIG7 is a schematic structural diagram of a communication device provided by the present application;

[0050] FIG8 is a schematic structural diagram of another communication device provided by the present application;

[0051] FIG9 is a schematic structural diagram of yet another communication device provided in this application. DETAILED DESCRIPTION

[0052] In the description of this application, unless otherwise specified, " / " indicates that the objects associated before and after are in an "or" relationship, for example, A / B can represent A or B; "and / or" in this application is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural.

[0053] In the description of this application, unless otherwise specified, "plurality" means two or more than two. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0054] In addition, to facilitate the clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, the words "first" and "second" are used to distinguish between identical or similar items with substantially the same functions and effects. Those skilled in the art will understand that the words "first" and "second" do not limit the quantity or execution order, and the words "first" and "second" do not necessarily mean different.

[0055] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner to facilitate understanding.

[0056] It will be understood that the “embodiment” mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present application. Therefore, the various embodiments throughout the specification do not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It will be understood that in the various embodiments of the present application, the size of the sequence number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0057] It can be understood that in this application, "when", "when", "if" and "under the circumstances" all mean that corresponding processing will be taken under certain objective circumstances, but it does not limit the time, nor does it require any judgment action when implementing it, nor does it mean that there are other limitations.

[0058] It is understood that some optional features in the embodiments of the present application may, in certain scenarios, be implemented independently of other features, such as the solution on which they are currently based, to solve corresponding technical problems and achieve corresponding effects. They may also be combined with other features in certain scenarios as needed. Accordingly, the devices provided in the embodiments of the present application may also implement these features or functions accordingly, which will not be described in detail here.

[0059] In this application, unless otherwise specified, the same or similar parts between the various embodiments can refer to each other. In the various embodiments of this application, unless otherwise specified and there is no logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other, and the technical features in different embodiments can be combined to form new implementation methods based on their inherent logical relationships. The implementation methods of this application described below do not constitute a limitation on the scope of protection of this application.

[0060] Wireless sensing is a key technology for the future. In wireless sensing, a transmitting device sends a specific signal (called a transmitted signal), and a receiving device receives the reflected signal from the environment (called a received signal). The transceiver then compares the received signal with the transmitted signal to analyze relevant information about the surrounding environment. For example, this information can be used to analyze the presence of objects to be detected or sensed, the distance between the scatterer and the transceiver, the orientation or angle of the scatterer relative to the transceiver, and the speed of the scatterer relative to the transceiver.

[0061] Wireless sensing can be widely applied in various fields. For example, in the connected vehicle (V2X) scenario, vehicles can use wireless sensing to obtain information about their surroundings, such as the location and speed of moving objects like other vehicles and pedestrians, and information about relatively stationary objects like road surfaces and fences. In airports, for example, specialized equipment can be deployed to monitor and sense flying objects like drones, preventing them from impacting aircraft takeoff and landing. In homes, wireless sensing can be used to detect intruders, improving security and privacy. In the future, wireless sensing may become a key component of mobile communication systems, achieving integrated communication and sensing.

[0062] 3GPP is conducting research and standardization work on integrated communication and perception. In the sidelink (SL), terminal devices can perceive data by sending and receiving data themselves or by sending and receiving data from others.

[0063] Typically, terminal devices need to maintain synchronization to avoid mutual interference. In current SL communications, synchronization sources can include: global navigation satellite systems (GNSS), access network equipment (such as base stations), terminal devices (such as user equipment (UE)), and the terminal device's internal clock.

[0064] Regardless of whether the terminal device is within or outside the network coverage area, as long as the terminal device can search for a reliable GNSS signal, the terminal device can select GNSS as the synchronization source. If the terminal device is within the coverage area of ​​the access network device and searches for the synchronization signal sent by the access network device, the terminal device can select the access network device as the synchronization source.

[0065] In addition, if a terminal device obtains synchronization information, it can send synchronization information on the SL to assist other terminal devices that cannot synchronize with GNSS and access network equipment to synchronize with the SL. In this case, the terminal device is called the synchronization reference UE.

[0066] If the terminal device cannot obtain synchronization information through GNSS, access network equipment and synchronization reference UE, the terminal device can determine the synchronization information based on its internal clock, that is, the synchronization source is the clock of the terminal device itself.

[0067] Exemplarily, the synchronization reference UE can provide synchronization information to other terminal devices by sending a sidelink synchronization signal block (S-SSB). S-SSB includes a sidelink synchronization signal (SLSS) and a physical sidelink broadcast channel (PSBCH). SLSS can be divided into a sidelink primary synchronization signal (S-PSS) and a sidelink secondary synchronization signal (S-SSS). PSBCH carries a master information block (MIB), which may include a direct frame number (DFN) and a slot index, etc. Other terminal devices can perform symbol synchronization with the synchronization reference UE by detecting the S-PSS and S-SSS, and perform frame synchronization with the synchronization reference UE by parsing the PSBCH.

[0068] A terminal device can send S-SSB to provide synchronization information when the following conditions are met: a) the terminal device selects GNSS or access network equipment as the synchronization source, but the reference signal received power (RSRP) of the GNSS signal or the synchronization signal of the access network device is less than the threshold; b) the terminal device selects the synchronization reference UE as the synchronization source, but the RSRP of the PSBCH of the synchronization reference UE (denoted as PSBCH-RSRP) is less than the threshold; c) the terminal device does not select GNSS, access network equipment and synchronization reference UE, but uses its own internal clock as the synchronization source.

[0069] Typically, different types of synchronization sources have a priority order. For example, when GNSS is configured as the highest priority, the priority order for synchronization sources is: GNSS > terminal devices synchronized with GNSS > access network devices > terminal devices synchronized with access network devices > other synchronization reference terminal devices > terminal device internal clock. When access network devices are configured as the highest priority, the priority order for synchronization sources is: access network devices > terminal devices synchronized with access network devices > GNSS > terminal devices synchronized with GNSS > other synchronization reference terminal devices > terminal device internal clock.

[0070] After the terminal device selects a synchronization source, it can reselect the synchronization source to change the synchronization source when the following conditions are met: a) the terminal device has selected a synchronization reference terminal device as the synchronization source and detected a synchronization source with a higher priority, or detected a synchronization source with the same priority but a higher PSBCH-RSRP, or the PSBCH-RSRP of the current synchronization source no longer meets the threshold requirement; b) the terminal device has selected GNSS as the synchronization source and detected that the PSBCH-RSRP of the candidate synchronization reference terminal device meets the threshold requirement, and the priority of the candidate synchronization reference terminal device is higher than GNSS, or the current GNSS becomes unreliable; c) the terminal device has selected an access network device as the synchronization source and detected that the PSBCH-RSRP of the candidate synchronization reference terminal device meets the threshold requirement, and the priority of the candidate synchronization reference terminal device is higher than the access network device, or the terminal device is not within the coverage of the cell.

[0071] In the SL communication and perception integration scenario, there may be different types of terminal devices with perception capabilities. For example, terminal devices with perception capabilities and traditional (legacy) communication functions (hereinafter referred to as integrated synesthesia terminal devices); terminal devices with perception capabilities but without channel encoding and decoding and modulation and demodulation capabilities in traditional communications (hereinafter referred to as perception-only terminal devices). Exemplarily, the perception capabilities may include but are not limited to: sending sequences, detecting sequences, performing correlation operations based on sequences, analyzing whether there are objects to be detected or perceived in the surrounding environment based on the results of correlation operations, the distance between the scatterer and the transceiver, the orientation or angle of the scatterer relative to the transceiver, the moving speed of the scatterer relative to the transceiver, etc.

[0072] The all-sensory terminal device can parse both the legacy S-SSB (legacy S-SSB) and the sequence-based S-SSB (sequence-based S-SSB). The perception-only terminal device can parse the sequence-based S-SSB, but cannot parse the legacy S-SSB. For example, the MIB carried by the PSBCH of the legacy S-SSB is sent after channel coding and modulation, and the MIB carried by the PSBCH of the sequence-based S-SSB (denoted as Seq-PSBCH) is carried by sequence without channel coding and modulation. In addition, for the legacy S-SSB and sequence-based S-SSB, S-PSS and S-SSS are both generated based on the sequence.

[0073] For example, Figures 1 and 2 are schematic diagrams of the structures of traditional S-SSB and sequence-based S-SSB, respectively. As shown in Figures 1 and 2, the PSBCH of S-SSB can be located in orthogonal frequency domain multiplexing (OFDM) symbol 0 and OFDM symbols 5-12 in the time slot. The S-PSS can be located in OFDM symbols 1-2 in the time slot, and the S-SSS can be located in OFDM symbols 3-4 in the time slot. OFDM symbol 13 serves as a guard interval.

[0074] For traditional S-SSB, the PSBCH carries the MIB. The PSBCH transmission process may include, for example, generating the MIB, adding a cyclic redundancy check (CRC) code, encoding, and modulation, which may be quadrature amplitude modulation (QAM). The PSBCH parsing process may include equalization, demodulation, and decoding.

[0075] For sequence-based S-SSB, Seq-PSBCH also carries the MIB, but the MIB is carried via the sequence, or in other words, the MIB can be mapped via the sequence without coding or modulation. Accordingly, Seq-PSBCH parsing can be performed based on correlation operations, that is, the sequence carried in the PSBCH is determined based on the correlation operation, thereby determining the MIB.

[0076] Due to the capability limitations of perception-only terminal devices, the above-mentioned synchronization schemes may not be able to synchronize the synaesthesia terminal device and the perception-only terminal device when the synaesthesia terminal device has selected a traditional synchronization source. Exemplarily, the traditional synchronization source may be a GNSS, an access network device, or a traditional synchronization reference terminal device, and the traditional synchronization reference terminal device includes a synaesthesia terminal device or a traditional terminal device synchronized with a GNSS / access network device. A traditional terminal device may refer to a terminal device that has communication capabilities (such as channel encoding and decoding and modulation and demodulation capabilities) but does not have perception capabilities.

[0077] For example, as shown in Figure 3, when the synesthesia terminal device has selected the traditional synchronization source, if the subsequent synesthesia terminal device detects the sequence-based S-SSB of the perception-only terminal device, then the perception-only terminal device can be considered as other synchronization reference terminal devices. Based on the existing synchronization source priority order (GNSS>terminal device synchronized with GNSS>access network device>terminal device synchronized with access network device>other synchronization reference terminal devices, or access network device>terminal device synchronized with access network device>GNSS>terminal device synchronized with GNSS>other synchronization reference terminal devices), the synesthesia terminal device will keep the existing synchronization source unchanged, and will not synchronize with the perception-only terminal device according to the sequence-based S-SSB of the perception-only terminal device.

[0078] In addition, even if the all-in-one terminal device sends its synchronization information through the traditional S-SSB, due to capability limitations, the perception-only terminal device cannot parse the traditional S-SSB, and thus cannot synchronize with the all-in-one terminal device based on the traditional S-SSB.

[0079] Based on this, the present application provides a synchronization method. After detecting the sequence-based S-SSB of the perception-only terminal device, the synesthesia integrated terminal device can send a sequence-based S-SSB and carry the current synchronization information of the synesthesia integrated terminal device therein, so that the perception-only terminal device can parse the S-SSB, and thus synchronize with the synesthesia integrated terminal device according to the synchronization information in the S-SSB, so as to reduce or avoid interference between the perception-only terminal device and the synesthesia integrated terminal device.

[0080] The technical solutions of the embodiments of the present application can be used for perception scenarios in various systems, which may be 3GPP communication systems, for example, fifth-generation (5G) or sixth-generation (6G) mobile communication systems, communication perception integrated systems, ultra-wideband (UWB) systems, vehicle to everything (V2X) systems, or device-to-device (D2D) communication systems, machine to machine (M2M) communication systems, Internet of Things (IoT), and other next-generation communication systems. The communication system may also be a non-3GPP communication system, such as a wireless local area network (WLAN) system such as Wi-Fi, without limitation.

[0081] Among them, the above-mentioned systems and communication scenarios applicable to the present application are only examples. The communication systems and communication scenarios applicable to the present application are not limited to these. They are uniformly described here and will not be repeated below.

[0082] 4 shows a communication system provided in an embodiment of the present application. The communication system includes a first terminal device and a second terminal device. The first terminal device and the second terminal device are of different types, or have different capabilities.

[0083] Exemplarily, the first terminal device has sensing capability but does not have channel coding and decoding and channel modulation and demodulation capabilities. The second terminal device has sensing capability and channel coding and decoding and channel modulation and demodulation capabilities.

[0084] For example, the first terminal device may also be called a perception-only terminal device, and the second terminal device may also be called a synaesthesia-integrated terminal device. Of course, the first terminal device and the second terminal device may also have other names, which are not specifically limited in this application.

[0085] Optionally, in addition to the first terminal device, the communication system may also include other perception-only terminal devices, such as a third terminal device. In addition to the second terminal device, the communication system may also include other synaesthesia-integrated terminal devices. In addition, the communication system may also include traditional terminal devices, such as terminal devices with communication capabilities but no perception capabilities.

[0086] In this embodiment of the present application, it is assumed that the second terminal device has selected a traditional synchronization source, which may include, for example, GNSS, access network equipment, an integrated terminal device synchronized with GNSS / access network equipment, or a traditional terminal device.

[0087] Optionally, the first terminal device and the second terminal device may share a SL resource pool. Alternatively, the first terminal device and the second terminal device may not share a SL resource pool, for example, the first terminal device uses resource pool 1 and the second terminal device uses another resource pool 2.

[0088] In the embodiment of the present application, the terminal device may be a user-side device with wireless transceiver functions, or may be a chip or chip system provided in the device. The terminal device may also be referred to as UE, terminal, access terminal, user unit, user station, mobile station (MS), remote station, remote terminal, mobile terminal (MT), user terminal, wireless communication device, user agent or user device, etc. The terminal device may be, for example, a terminal device in IoT, V2X, D2D, M2M, 5G network, or a future evolved public land mobile network (PLMN). The terminal device may be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; it may also be deployed on water (such as ships, etc.); it may also be deployed in the air (such as airplanes, balloons and satellites, etc.).

[0089] Exemplarily, the terminal device may be a drone, an IoT device (e.g., a sensor, an electricity meter, a water meter, etc.), a V2X device, a station (ST) in a WLAN, a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA) device, a handheld device with a wireless communication function, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a wearable device (also referred to as a wearable smart device), a tablet computer or a computer with a wireless transceiver function, a virtual reality (VR) terminal, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical care, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a smart home, or a similar device. The terminal device can be a mobile or fixed device, which is not specifically limited in this application.

[0090] In an embodiment of the present application, the access network device may be a network-side device with wireless transceiver functions, or may be a chip or chip system arranged in the device, located in the radio access network (RAN) of the mobile communication system, and used to provide access services for terminal devices. The access network device can be an evolved base station (eNB or eNodeB) in an LTE or evolved LTE system (LTE-Advanced, LTE-A), such as a traditional macro base station eNB and a micro base station eNB in ​​a heterogeneous network scenario; or it can be a next generation node B (gNodeB or gNB) in a 5G system; or it can be a transmission reception point (TRP); or it can be a base station in a future evolved PLMN; or it can be a broadband network gateway (BNG), an aggregation switch or a non-3GPP access device; or it can be a wireless controller in a cloud radio access network (CRAN); or it can be an access point (AP) in a WiFi system; or it can be a wireless relay node or a wireless backhaul node; or it can be a device that implements base station functions in IoT, V2X, D2D, or M2M, and the embodiments of the present application do not specifically limit this. Exemplarily, the base stations in the embodiments of the present application may include various forms of base stations, such as: macro base stations, micro base stations (also called small stations), relay stations, access points, etc., and the embodiments of the present application do not specifically limit this.

[0091] In some implementation scenarios, the access network device may also be a module or unit that can implement some or all of the functions of a base station. For example, the access network device may be a centralized unit (CU), a distributed unit (DU), a CU and a DU, a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU). The CU and DU may be configured separately or included in the same network element, such as a baseband unit (BBU). The RU may be included in a radio frequency device or radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH).

[0092] In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, the access network device may be an access network device or a module of an access network device in an open radio access network (open RAN, ORAN) system. In the ORAN system, CU may also be referred to as open (open, O)-CU, DU may also be referred to as O-DU, CU-CP may also be referred to as O-CU-CP, CU-UP may also be referred to as O-CU-UP, and RU may also be referred to as O-RU. Any of the CU (or CU-CP, CU-UP), DU and RU in this application may be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0093] In some implementation scenarios, the access network device may also be referred to as a RAN node or a RAN device or an access network device, or the access network device may also have other naming methods, which is not specifically limited in this application.

[0094] All or part of the functions of the terminal device or access network device in this application may also be implemented through software functions running on hardware, or through virtualization functions instantiated on a platform (such as a cloud platform). The terminal device in this application may also be a logical node, logical module or software that can implement all or part of the terminal device functions.

[0095] The following will describe the synchronization method provided in the embodiment of the present application in detail with reference to the accompanying drawings, taking the interaction between the first terminal device and the second terminal device shown in FIG4 as an example.

[0096] FIG5 is a flow chart of a synchronization method provided in an embodiment of the present application, which includes the following steps:

[0097] S501: A first terminal device sends a first S-SSB. Correspondingly, a second terminal device receives the first S-SSB from the first terminal device.

[0098] The first S-SSB indicates the first synchronization information. The first S-SSB is a sequence-based S-SSB. The sequence-based S-SSB can refer to the aforementioned related descriptions and will not be repeated here.

[0099] Optionally, the synchronization source of the first synchronization information is the first synchronization source. Exemplarily, as shown in FIG6 , before step S501 , the first terminal device may select the first synchronization source, obtain the first synchronization information from the first synchronization source, and synchronize with the first synchronization source according to the first synchronization information.

[0100] Exemplarily, the first synchronization source is the internal clock of the first terminal device or the third terminal device. The third terminal device has perception capabilities, but does not have channel coding and decoding and channel modulation and demodulation capabilities. It is understandable that since the first terminal device and the third terminal device do not have channel coding and decoding and channel modulation and demodulation capabilities, the first terminal device and the third terminal device cannot select GNSS, access network equipment, and synesthesia terminal devices or traditional terminal devices synchronized with GNSS / access network equipment as synchronization sources. That is, the synchronization sources of the first terminal device and the third terminal device are not GNSS, access network equipment, and synesthesia terminal devices or traditional terminal devices synchronized with GNSS / access network equipment.

[0101] Optionally, when the first synchronization source is a third terminal device, the first synchronization source may also be referred to as a perception-only synchronization source. Of course, the first synchronization source may also have other names, which are not specifically limited in this application.

[0102] S502: The second terminal device sends a second S-SSB to the first terminal device based on the signal quality of the first S-SSB. Correspondingly, the first terminal device receives the second S-SSB from the second terminal device.

[0103] The second S-SSB indicates the second synchronization information and the synchronization source of the second synchronization information is the second synchronization source. The second synchronization source includes but is not limited to GNSS, access network equipment, and terminal equipment synchronized with GNSS or access network equipment (such as a telepathic terminal device or a traditional terminal device). Exemplarily, the second synchronization source may also be referred to as a traditional synchronization source.

[0104] Optionally, before step S501, the second terminal device may obtain second synchronization information and synchronize according to the second synchronization information. That is, as shown in FIG6 , before step S501, the method further includes: the second synchronization source sends the second synchronization information, and accordingly, the second terminal device receives the second synchronization information from the second synchronization source and synchronizes with the second synchronization source according to the second synchronization information.

[0105] Optionally, the second terminal device may be located outside the coverage of the access network device or within the coverage of the access network device. For example, if the second synchronization source is the access network device, the second terminal device is located within the coverage of the access network device; if the second synchronization source is GNSS and the terminal device is synchronized with the GNSS / access network device, the second terminal device may be located within the coverage of the access network device or outside the coverage of the access network device.

[0106] Optionally, in step S501, the second terminal device may learn that the first S-SSB is a sequence-based S-SSB. Since both the perception-only terminal device and the synesthesia-integrated terminal device can send sequence-based S-SSBs, the second terminal device may determine that the first terminal device may be a perception-only terminal device or a synesthesia-integrated terminal device. In order to enable the first terminal device to learn the second synchronization information, the second terminal device may send a second sequence-based S-SSB, indicating the second synchronization information and indicating that the synchronization source of the second synchronization information is the second synchronization source through the second S-SSB. Since the second S-SSB is a sequence-based S-SSB, regardless of whether the first terminal device is a perception-only terminal device or a synesthesia-integrated terminal device, it can receive and parse the second S-SSB. If the second S-SSB is a traditional S-SSB, then when the first terminal device is a perception-only terminal device, the first terminal device cannot parse the second S-SSB.

[0107] Optionally, the second terminal device may send a second S-SSB to the first terminal device when the signal quality of the first S-SSB is greater than or equal to the first threshold. Exemplarily, the signal quality can be represented by RSRP, reference signal received quality (RSRQ), signal to interference plus noise ratio (SINR), etc., which is not specifically limited in this application. The first threshold may be predefined by the protocol, or may be determined by the second terminal device itself, or may be preconfigured by the access network device, or may be preconfigured by the second terminal device when it leaves the factory, which is not specifically limited in this application.

[0108] In addition, the second terminal device may also send the second S-SSB to the first terminal device in other ways according to the signal quality of the first S-SSB. For example, when the signal quality of the first S-SSB is within a certain signal quality range, the second S-SSB is sent to the first terminal device. This application does not limit the specific implementation of the second terminal device sending the second S-SSB to the first terminal device according to the signal quality of the S-SSB.

[0109] Optionally, after receiving the first S-SSB, the second terminal device sends a second S-SSB to indicate the synchronization information (i.e., the second synchronization information) obtained by the second terminal device before receiving the first S-SSB, indicating that the second terminal device did not change the synchronization source after receiving the first synchronization information, that is, it kept the second synchronization source selected previously unchanged. At the same time, it implies that the priority of the second synchronization source is higher than the priority of the synchronization source of the first synchronization information (i.e., the first synchronization source). That is, since the priority of the second synchronization source is higher than the priority of the first synchronization source, the second terminal device still selects the second synchronization source.

[0110] The second S-SSB is a sequence-based S-SSB. Therefore, the first terminal device can parse the second S-SSB to obtain the second synchronization information and the synchronization source of the second synchronization information. Exemplarily, the second S-SSB includes SLSS and PSBCH. SLSS includes S-PSS and S-SSS. PSBCH carries the MIB.

[0111] Optionally, the second S-SSB indicating the second synchronization information may include: the second S-SSB includes the second synchronization information. The second synchronization information may be located in the SLSS and / or the MIB. For example, the SLSS maps information used for OFDM symbol synchronization in the second synchronization information, and the MIB includes information used for frame synchronization in the second synchronization information.

[0112] Optionally, the second S-SSB indicates the synchronization source of the second synchronization information, which can also be understood as: the second S-SSB indicates the synchronization source type of the second synchronization information. In this case, the second synchronization source can be understood as a synchronization source type rather than a specific device.

[0113] Optionally, since the second synchronization source may be GNSS, an access network device, or a terminal device synchronized with the GNSS or the access network device, the second S-SSB may also indicate the specific type of the synchronization source of the second synchronization information. For example, when the second synchronization source is GNSS, the second S-SSB may indicate the second synchronization information and indicate that the synchronization source of the second synchronization information is GNSS; when the second synchronization source is an access network device, the second S-SSB may indicate the second synchronization information and indicate that the synchronization source of the second synchronization information is the access network device.

[0114] As a possible implementation, the second S-SSB may include indication information, where the indication information is used to indicate that the synchronization source of the second synchronization information is the second synchronization source, or the indication information is used to indicate that the synchronization source of the second synchronization information is a GNSS, an access network device, or a terminal device synchronized with the GNSS / access network device. The indication information may be located in the MIB of the second S-SSB.

[0115] In the case where the indication information is used to indicate that the synchronization source of the second synchronization information is the second synchronization source, exemplarily, the indication information may be a 1-bit indicator. When the value of the bit is a preset value (such as "0" or "1"), it indicates that the synchronization source of the second synchronization information is the second synchronization source; or, the indication information may be a flag bit. When the second S-SSB includes the flag bit, it indicates that the synchronization source of the second synchronization information is the second synchronization source; or, the indication information may be an enumeration value. When the value of the enumeration value is a preset value (such as "true"), it indicates that the synchronization source of the second synchronization information is the second synchronization source.

[0116] In the case where the indication information is used to indicate that the synchronization source of the second synchronization information is GNSS, an access network device, or a terminal device synchronized with the GNSS / access network device, the indication information may illustratively be a 2-bit indication, where different values ​​of the 2 bits indicate the specific type of the synchronization source of the second synchronization information. For example, the synchronization source of the second synchronization information indicated by the value of the 2 bits may be as shown in Table 1.

[0117] Table 1

[0118] It should be noted that the synchronization source of the second synchronization information indicated by the 2-bit value may also have other implementations, for example, "00" indicates that the synchronization source of the second synchronization information is the access network device, "01" indicates that the synchronization source of the second synchronization information is GNSS, etc. This application does not make specific limitations on this.

[0119] As another possible implementation, the synchronization source of the second synchronization information may be indicated by the set to which the sequence corresponding to the SLSS in the second S-SSB belongs. For example, when the sequence corresponding to the SLSS is in a preset sequence set, the synchronization source of the second synchronization information is indicated as the second synchronization source, or the synchronization source of the second synchronization information is indicated as the GNSS, an access network device, or a terminal device synchronized with the GNSS / access network device.

[0120] In the case where the synchronization source indicating the second synchronization information is the second synchronization source, exemplarily, two sequence sets (denoted as the first sequence set and the second sequence set) can be pre-defined, each sequence set includes at least one sequence, and the sequences in the sequence set can be used to generate SLSS (S-PSS and / or S-SSS). In addition, the first sequence set and the second sequence set can be defined to correspond to the first synchronization source and the second synchronization source, respectively. That is, when the transmitting end uses the sequence in the first sequence set to generate SLSS, or when the receiving end detects that the sequence corresponding to the SLSS is a sequence in the first sequence set, it indicates that the synchronization source of the synchronization information indicated by the S-SSB is the first synchronization source. Similarly, when the transmitting end uses the sequence in the second sequence set to generate SLSS, or when the receiving end detects that the sequence corresponding to the SLSS is a sequence in the second sequence set, it indicates that the synchronization source of the synchronization information indicated by the S-SSB is the second synchronization source.

[0121] In this example, the preset sequence set is the second sequence set. That is, the second terminal device can use the sequence in the second sequence set to generate the SLSS in the second S-SSB. When the first terminal device detects that the sequence corresponding to the SLSS in the second S-SSB is in the second sequence set, it can determine that the synchronization source of the second synchronization information is the second synchronization source.

[0122] In the case where the synchronization source indicating the second synchronization information is GNSS, access network equipment, or a terminal device synchronized with GNSS / access network equipment, illustratively, five sequence sets can be pre-defined, respectively recorded as sequence sets 1-5. Each sequence set includes at least one sequence, and the sequences in the sequence set can be used to generate SLSS (S-PSS and / or S-SSS). In addition, sequence sets 1-5 can be defined to correspond to the first synchronization source, GNSS, access network equipment, terminal equipment synchronized with GNSS, and terminal equipment synchronized with the access network equipment, respectively. At this time, if the sequence corresponding to SLSS is a sequence in sequence set 2, it means that the synchronization source of the synchronization information indicated by S-SSB is GNSS; if the sequence corresponding to SLSS is a sequence in sequence set 3, it means that the synchronization source of the synchronization information indicated by S-SSB is the access network equipment, and so on.

[0123] S503. The first terminal device updates the synchronization information from the first synchronization information to the second synchronization information.

[0124] Optionally, the first terminal device may update the synchronization information from the first synchronization information to the second synchronization information based on an indication that the synchronization source of the second synchronization information is the second synchronization source. That is, for the first terminal device, if the synchronization source of a certain synchronization information received by the first terminal device is the second synchronization source, the first terminal device will regard the synchronization information as the latest (or current) synchronization information, that is, the first terminal device updates the synchronization source.

[0125] Exemplarily, the first terminal device may update the synchronization information from the first synchronization information to the second synchronization information according to a priority order of the synchronization sources, wherein the priority order of the synchronization sources includes that the priority of the second synchronization source is higher than the priority of the first synchronization source.

[0126] Optionally, the first terminal device updating the synchronization information from the first synchronization information to the second synchronization information can also be understood as: the first terminal device synchronizing with the second terminal device based on the second synchronization information. Alternatively, it can also be understood as: the first terminal device updating the synchronization source from the first synchronization source to the second terminal device. Since the synchronization source selected by the second terminal device is the second synchronization source, it can also be considered that the first terminal device updates the synchronization source to the second synchronization source.

[0127] For example, when the first synchronization source is the internal clock of the first terminal device, the second terminal device can serve as an additional synchronization reference terminal device for the first terminal device. In this case, according to the priority order: other synchronization reference terminal devices > internal clock, the first terminal device updates the synchronization source to the second terminal device. When the first synchronization source is the third terminal device, both the second and third terminal devices serve as additional synchronization reference terminal devices. However, for the first terminal device, the second terminal device is a traditional synchronization source, and the third terminal device is a perception-only synchronization source. Therefore, according to the priority order: traditional synchronization source > perception-only synchronization source, the first terminal device updates the synchronization source to the second terminal device.

[0128] Based on this solution, after receiving the first sequence-based S-SSB from the first terminal device, the second terminal device sends a second sequence-based S-SSB, and indicates through the second S-SSB that the synchronization source is the second synchronization information of the traditional synchronization source (i.e., the second synchronization source). Since the second S-SSB is a sequence-based S-SSB, the first terminal device can parse the second S-SSB to obtain the second synchronization information and its synchronization source, and then update the synchronization information to the second synchronization information, thereby achieving synchronization between the first terminal device and the second terminal device.

[0129] In one possible implementation, in step S501 above, the first S-SSB sent by the first terminal device may be broadcast. In this scenario, there may be multiple second terminal devices. After receiving the first S-SSB, each of the multiple second terminal devices may send a second S-SSB to indicate their respective synchronization information and the synchronization source of the synchronization information.

[0130] Optionally, the synchronization information of the multiple second terminal devices may be different. For example, there are second terminal device 1 and second terminal device 2, the synchronization information of second terminal device 1 is second synchronization information 1, the synchronization source of which is GNSS, and the synchronization information of second terminal device 2 is second synchronization information 2, the synchronization source of which is an access network device.

[0131] As an example, the second terminal device 1 may send a second S-SSB1 to indicate the second synchronization information 1 and to indicate that the synchronization source of the second synchronization information 1 is a traditional synchronization source, and the second terminal device 2 may send a second S-SSB2 to indicate the second synchronization information 2 and to indicate that the synchronization source of the second synchronization information 2 is a traditional synchronization source.

[0132] In this scenario, since the second S-SSB sent by multiple second terminal devices can only indicate that the selected synchronization source is a traditional synchronization source, it cannot indicate whether it is a GNSS, an access network device, or a terminal device synchronized with the GNSS / access network device. Therefore, the first terminal device can select the second S-SSB with the strongest signal quality among the multiple second S-SSBs sent by multiple second terminal devices, and synchronize according to the synchronization information indicated by the second S-SSB.

[0133] As another example, the second terminal device 1 may send a second S-SSB1 to indicate the second synchronization information 1 and to indicate that the synchronization source of the second synchronization information 1 is GNSS, and the second terminal device 2 may send a second S-SSB2 to indicate the second synchronization information 2 and to indicate that the synchronization source of the second synchronization information 2 is an access network device.

[0134] In this scenario, the first terminal device can synchronize with the second terminal device 1 according to the synchronization source priority 1 "GNSS>terminal device synchronized with GNSS>access network device>terminal device synchronized with access network device>other synchronization reference terminal devices>terminal device internal clock" according to the synchronization information 1. Alternatively, the first terminal device can synchronize with the second terminal device 2 according to the synchronization source priority 2 "access network device>terminal device synchronized with access network device>GNSS>terminal device synchronized with GNSS>other synchronization reference terminal devices" according to the synchronization information 2. Among them, whether to use synchronization source priority 1 or synchronization source priority 2 can be defined by the protocol, or can be configured by the access network device, or can be determined by the first terminal device itself, and there is no limitation.

[0135] In one possible implementation, in step S502 above, the second S-SSB sent by the second terminal device may be broadcast. In this scenario, in addition to the first terminal device, there may be other perception-only terminal devices (referred to as the fourth terminal device) that can receive the second S-SSB. At this time, the fourth terminal device may also determine the synchronization source as the second terminal device, and synchronize with the second terminal device according to the second synchronization information indicated by the second S-SSB.

[0136] Optionally, before receiving the second S-SSB, the fourth terminal device may select its internal clock or other perception-only terminal device as the synchronization source, and determine that the synchronization information of the synchronization source is the third synchronization information. However, the present application does not limit the fourth terminal device to sending a third S-SSB to indicate the third synchronization information. Alternatively, before receiving the second S-SSB, the fourth terminal device may not select any synchronization source. That is, the implementation of the fourth terminal device is similar to that of the first terminal device, except that the fourth terminal device may not send an S-SSB before receiving the second S-SSB.

[0137] In one possible implementation, step S501 may not be performed, and in step S502, the second terminal device may directly send the second S-SSB. That is, once the second terminal device selects the second synchronization source, the second terminal device may send the second S-SSB. Alternatively, if the second terminal device selects the second synchronization source, the second terminal device may send the second S-SSB when the S-SSB transmission conditions defined in the existing protocol are met. In other words, the second terminal device does not need to send the second S-SSB based on the signal quality of the sequence-based S-SSB after receiving the sequence-based S-SSB.

[0138] In one possible implementation, in addition to the second S-SSB, the second terminal device may also send a fourth S-SSB, where the fourth S-SSB may be a legacy S-SSB. The fourth S-SSB may indicate second synchronization information and may be used for synchronization between the legacy terminal device and the second terminal device.

[0139] It is understood that in each of the above embodiments, the methods and / or steps implemented by the terminal device may also be implemented by components (e.g., a processor, chip, chip system, circuit, logic module, or software) that can be used in the terminal device. The chip system may be composed of a chip, or the chip system may include a chip and other discrete devices.

[0140] It is understandable that, in order to realize the above functions, the communication device includes hardware structures and / or software modules corresponding to the execution of each function. It should be easily appreciated by those skilled in the art that, in combination with the units and algorithm steps of each example described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0141] The embodiment of the present application can divide the functional modules of the communication device according to the above method embodiment. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical functional division. In actual implementation, there may be other division methods.

[0142] Communication Device Figure 7 shows a schematic structural diagram of a communication device 70. The communication device 70 includes a processing module 701 and a transceiver module 702. The communication device 70 can be used to implement the functions of the first terminal device or the second terminal device described above.

[0143] In some embodiments, the communication device 70 may further include a storage module (not shown in FIG. 7 ) for storing program instructions and data.

[0144] In some embodiments, the transceiver module 702, which may also be referred to as a transceiver unit, is configured to implement a transmitting and / or receiving function. The transceiver module 702 may be composed of a transceiver circuit, a transceiver, a transceiver, or a communication interface.

[0145] In some embodiments, the transceiver module 702 may include a receiving module and a sending module, which are respectively used to execute the receiving and sending steps performed by the first terminal device or the second terminal device in the above method embodiment, and / or used to support other processes of the technology described herein; the processing module 701 may be used to execute the processing steps (such as determination, etc.) performed by the first terminal device or the second terminal device in the above method embodiment, and / or used to support other processes of the technology described herein.

[0146] When the communication device 70 is used to implement the function of the first terminal device:

[0147] The transceiver module 702 is used to send a first sidelink synchronization signal block S-SSB, where the first S-SSB indicates first synchronization information; the transceiver module 702 is also used to receive a second S-SSB from a second terminal device, where the second S-SSB indicates second synchronization information and indicates that the synchronization source of the second synchronization information is a second synchronization source, where the second synchronization source is one of the following: a global navigation satellite system GNSS, an access network device, or a terminal device synchronized with the GNSS or the access network device; the first S-SSB and the second S-SSB are sequence-based SSBs; the processing module 701 is used to update the synchronization information from the first synchronization information to the second synchronization information.

[0148] Optionally, the synchronization source of the first synchronization information is the first synchronization source, which is the internal clock of the first terminal device or the third terminal device. The first terminal device and the third terminal device have perception capabilities but do not have channel encoding and decoding and channel modulation and demodulation capabilities.

[0149] Optionally, the synchronization source of the first synchronization information is the first synchronization source. The processing module 701 is used to update the synchronization information from the first synchronization information to the second synchronization information, including: the processing module 701 is used to update the synchronization information from the first synchronization information to the second synchronization information according to the priority order of the synchronization sources; the priority order of the synchronization sources includes that the priority of the second synchronization source is higher than the priority of the first synchronization source.

[0150] Optionally, the second S-SSB includes indication information, where the indication information is used to indicate that the synchronization source of the second synchronization information is the second synchronization source, and the indication information is located in the main information block of the second S-SSB.

[0151] Optionally, the second S-SSB includes a side link synchronization signal SLSS, and when a sequence corresponding to the SLSS is in a preset sequence set, it indicates that the synchronization source of the second synchronization information is the second synchronization source.

[0152] When the communication device 70 is used to implement the function of the second terminal device:

[0153] The transceiver module 702 is used to receive a first sidelink synchronization signal block S-SSB from the first terminal device; the transceiver module 702 is also used to send a second S-SSB to the first terminal device according to the signal quality of the first S-SSB; wherein the second S-SSB indicates second synchronization information and the synchronization source indicating the second synchronization information is a second synchronization source, and the second synchronization source is one of the following: a global navigation satellite system GNSS, an access network device, or a terminal device synchronized with the GNSS or the access network device; the first S-SSB and the second S-SSB are sequence-based SSBs.

[0154] Optionally, the transceiver module 702 is used to send a second S-SSB to the first terminal device based on the signal quality of the first S-SSB, including: the transceiver module 702 is used to send a second S-SSB to the first terminal device when the signal quality of the first S-SSB is greater than or equal to a first threshold.

[0155] Optionally, the second S-SSB includes indication information, where the indication information is used to indicate that the synchronization source of the second synchronization information is the second synchronization source, and the indication information is located in the main information block of the second S-SSB.

[0156] Optionally, the second S-SSB includes a side link synchronization signal SLSS, and when a sequence corresponding to the SLSS is in a preset sequence set, it indicates that the synchronization source of the second synchronization information is the second synchronization source.

[0157] Optionally, the transceiver module 702 is further configured to receive second synchronization information from a second synchronization source; and the processing module 701 is configured to synchronize with the second synchronization source according to the second synchronization information.

[0158] Optionally, the first S-SSB indicates the first synchronization information, the synchronization source of the first synchronization information is the first synchronization source, the first synchronization source is the internal clock of the first terminal device or the third terminal device, the first terminal device and the third terminal device have perception capabilities, but do not have channel encoding and decoding and channel modulation and demodulation capabilities; the priority of the first synchronization source is lower than the priority of the second synchronization source.

[0159] Among them, all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module and will not be repeated here.

[0160] In the present application, the communication device 70 may be presented in the form of functional modules divided in an integrated manner. The "module" here may refer to a specific application-specific integrated circuit (ASIC), a circuit, a processor and memory that executes one or more software or firmware programs, an integrated logic circuit, and / or other devices that can provide the above functions.

[0161] In some embodiments, when the communication device 70 in Figure 7 is a chip or a chip system, the function / implementation process of the transceiver module 702 can be implemented through the input and output interface (or communication interface) of the chip or chip system, and the function / implementation process of the processing module 701 can be implemented through the processor (or processing circuit) of the chip or chip system.

[0162] Since the communication device 70 provided in this embodiment can execute the above method, the technical effects that can be obtained can refer to the above method embodiments and will not be repeated here.

[0163] As a possible product form, the first terminal device or the second terminal device described in the embodiments of the present application can also be implemented using the following: one or more field programmable gate arrays (FPGAs), programmable logic devices (PLDs), controllers, state machines, gate logic, discrete hardware components, any other suitable circuits, or any combination of circuits that can perform the various functions described throughout this application.

[0164] As another possible product form, the first terminal device or the second terminal device described in the embodiment of the present application can be implemented by a general bus architecture. For ease of explanation, refer to Figure 8, which is a structural diagram of a communication device 800 provided in an embodiment of the present application, and the communication device 800 includes a processor 801 and a transceiver 802. The communication device 800 can be a first terminal device, or a chip or chip system therein; or, the communication device 800 can be a second terminal device, or a chip or module therein. Figure 8 only shows the main components of the communication device 800. In addition to the processor 801 and the transceiver 802, the communication device may further include a memory 803, and an input and output device (not shown in the figure).

[0165] Optionally, the processor 801 is primarily used to process communication protocols and communication data, as well as to control the entire communication device, execute software programs, and process data from the software programs, thereby implementing the methods provided in the above-mentioned method embodiments. The memory 803 is primarily used to store software programs and data. The transceiver 802 may include a radio frequency circuit and an antenna. The radio frequency circuit is primarily used to convert baseband signals into radio frequency signals and process radio frequency signals. The antenna is primarily used to transmit and receive radio frequency signals in the form of electromagnetic waves. Input and output devices, such as a touch screen, display screen, and keyboard, are primarily used to receive data input by a user and output data to the user.

[0166] Optionally, the processor 801 , the transceiver 802 , and the memory 803 may be connected via a communication bus.

[0167] When the communication device is powered on, the processor 801 can read the software program in the memory 803, interpret and execute the instructions of the software program, and process the data of the software program. When data needs to be sent wirelessly, the processor 801 performs baseband processing on the data to be sent and outputs the baseband signal to the radio frequency circuit. The radio frequency circuit performs radio frequency processing on the baseband signal and then transmits the radio frequency signal to the outside in the form of electromagnetic waves through the antenna. When data is sent to the communication device, the radio frequency circuit receives the radio frequency signal through the antenna, converts the radio frequency signal into a baseband signal, and outputs the baseband signal to the processor 801. The processor 801 converts the baseband signal into data and processes the data.

[0168] In another implementation, the RF circuit and antenna may be provided independently of the processor performing baseband processing. For example, in a distributed scenario, the RF circuit and antenna may be remotely arranged independent of the communication device.

[0169] In some embodiments, in terms of hardware implementation, those skilled in the art may conceive that the communication device 70 may take the form of the communication device 800 shown in FIG. 8 .

[0170] As an example, the functions / implementation process of the processing module 701 in FIG7 can be implemented by the processor 801 in the communication device 800 shown in FIG8 calling the computer-executable instructions stored in the memory 803. The functions / implementation process of the transceiver module 702 in FIG7 can be implemented by the transceiver 802 in the communication device 800 shown in FIG8.

[0171] As another possible product form, the first terminal device or the second terminal device in this application may adopt the structure shown in Figure 9, or include the components shown in Figure 9. Figure 9 is a schematic diagram of the structure of a communication device 900 provided in this application. The communication device 900 can be a first terminal device or a chip or system-on-chip in the first terminal device; or it can be a second terminal device or a module, chip, or system-on-chip in the second terminal device.

[0172] As shown in FIG9 , the communication device 900 includes at least one processor 901 and at least one communication interface ( FIG9 is merely an example of a communication interface 904 and a processor 901). Optionally, the communication device 900 may further include a communication bus 902 and a memory 903.

[0173] The processor 901 may be a general-purpose central processing unit (CPU), a general-purpose processor, a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The processor 901 may also be other devices with processing capabilities, such as circuits, devices, or software modules, without limitation.

[0174] Communication bus 902 is used to connect the various components in communication device 900, enabling communication between them. Communication bus 902 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, for example. This bus can be categorized as an address bus, a data bus, a control bus, and so on. For ease of illustration, FIG9 shows a single thick line, but this does not imply that there is only one bus or only one type of bus.

[0175] Communication interface 904 is used to communicate with other devices or communication networks. Exemplarily, communication interface 904 can be a module, circuit, transceiver, or any other device capable of communication. Optionally, communication interface 904 can also be an input / output interface within processor 901, used to implement signal input and output to the processor.

[0176] The memory 903 may be a device with a storage function, used to store instructions and / or data, wherein the instructions may be computer programs.

[0177] Exemplarily, the memory 903 may be a read-only memory (ROM) or other types of static storage devices that can store static information and / or instructions, or a random access memory (RAM) or other types of dynamic storage devices that can store information and / or instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, etc., without limitation.

[0178] It should be noted that the memory 903 can exist independently of the processor 901 or can be integrated with the processor 901. The memory 903 can be located within the communication device 900 or outside the communication device 900, without limitation. The processor 901 can be used to execute instructions stored in the memory 903 to implement the methods provided in the following embodiments of the present application.

[0179] As an optional implementation, the communication device 900 may further include an output device 905 and an input device 906. The output device 905 communicates with the processor 901 and can display information in a variety of ways. For example, the output device 905 can be a liquid crystal display (LCD), a light emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector. The input device 906 communicates with the processor 901 and can receive user input in a variety of ways. For example, the input device 906 can be a mouse, a keyboard, a touch screen device, or a sensor device.

[0180] In some embodiments, in terms of hardware implementation, those skilled in the art may conceive that the communication device 70 shown in FIG. 7 may take the form of the communication device 900 shown in FIG. 9 .

[0181] As an example, the functions / implementation process of the processing module 701 in FIG7 can be implemented by the processor 901 in the communication device 900 shown in FIG9 calling the computer-executable instructions stored in the memory 903. The functions / implementation process of the transceiver module 702 in FIG7 can be implemented by the communication interface 904 in the communication device 900 shown in FIG9.

[0182] It should be noted that the structure shown in FIG9 does not constitute a specific limitation on the first terminal device or the second terminal device. For example, in other embodiments of the present application, the first terminal device or the second terminal device may include more or fewer components than shown, or may combine or separate certain components, or arrange the components differently. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0183] In some embodiments, an embodiment of the present application further provides a communication device, which includes a processor for implementing the method in any of the above method embodiments.

[0184] As a possible implementation, the communication device further includes a memory. The memory is used to store necessary computer programs and data. The computer program may include instructions, and the processor may invoke the instructions in the computer program stored in the memory to instruct the communication device to perform any of the above-described method embodiments. Of course, the memory may not be located in the communication device.

[0185] As another possible implementation, the communication device also includes an interface circuit, which is a code / data read / write interface circuit, and the interface circuit is used to receive computer execution instructions (computer execution instructions are stored in a memory, may be read directly from the memory, or may pass through other devices) and transmit them to the processor.

[0186] As another possible implementation, the communication device further includes a communication interface, where the communication interface is used to communicate with a module outside the communication device.

[0187] It can be understood that the communication device can be a chip or a chip system. When the communication device is a chip system, it can be composed of chips or include chips and other discrete devices. The embodiments of the present application do not specifically limit this.

[0188] The present application also provides a computer-readable storage medium having a computer program or instruction stored thereon, which implements the functions of any of the above method embodiments when executed by a computer.

[0189] The present application also provides a computer program product, which implements the functions of any of the above method embodiments when executed by a computer.

[0190] Those skilled in the art will appreciate that, for the sake of convenience and brevity of description, the specific working processes of the above-described systems, devices, and units may refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0191] It is understood that the systems, devices, and methods described in this application may also be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection shown or discussed may be through some interface, indirect coupling or communication connection of devices or units, and may be electrical, mechanical, or other forms.

[0192] The units described as separate components may or may not be physically separate, i.e., they may be located in one place or distributed across multiple network units. Components shown as units may or may not be physical units. Some or all of these units may be selected to achieve the objectives of this embodiment as needed.

[0193] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0194] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware, or any combination thereof. When implemented using a software program, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more media integrated therein. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state drive (SSD)). In the embodiment of the present application, the computer may include the aforementioned device.

[0195] Although the present application is described herein in conjunction with various embodiments, in the process of implementing the claimed application, those skilled in the art can understand and implement other changes to the disclosed embodiments by reviewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple situations. A single processor or other unit can implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0196] Although the present application has been described with reference to specific features and embodiments thereof, it is apparent that various modifications and combinations may be made thereto without departing from the spirit and scope of the present application. Accordingly, this specification and the drawings are merely illustrative of the present application as defined by the appended claims and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, those skilled in the art may make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, the present application is intended to include such modifications and variations as fall within the scope of the claims of the present application and their equivalents.

Claims

1. A synchronization method, characterized in that: The method comprises: Sending a first sidelink synchronization signal block S-SSB, wherein the first S-SSB indicates first synchronization information; receiving a second S-SSB from a second terminal device, wherein the second S-SSB indicates second synchronization information and indicates that a synchronization source of the second synchronization information is a second synchronization source, wherein the second synchronization source is one of the following: a global navigation satellite system GNSS, an access network device, or a terminal device synchronized with the GNSS or the access network device; the first S-SSB and the second S-SSB are sequence-based SSBs; The synchronization information is updated from the first synchronization information to the second synchronization information.

2. The method according to claim 1, characterized in that The synchronization source of the first synchronization information is the first synchronization source, which is the internal clock of the first terminal device or the third terminal device. The first terminal device and the third terminal device have perception capabilities but do not have channel encoding and decoding and channel modulation and demodulation capabilities.

3. The method according to claim 1 or 2, characterized in that: The synchronization source of the first synchronization information is a first synchronization source; and updating the synchronization information from the first synchronization information to the second synchronization information includes: The synchronization information is updated from the first synchronization information to the second synchronization information according to a priority order of synchronization sources; the priority order of the synchronization sources includes that the priority of the second synchronization source is higher than the priority of the first synchronization source.

4. The method according to any one of claims 1 to 3, characterized in that: The second S-SSB includes indication information, where the indication information is used to indicate that the synchronization source of the second synchronization information is the second synchronization source, and the indication information is located in the main information block of the second S-SSB.

5. The method according to any one of claims 1 to 3, characterized in that: The second S-SSB includes a side link synchronization signal SLSS, and when a sequence corresponding to the SLSS is in a preset sequence set, it indicates that the synchronization source of the second synchronization information is the second synchronization source.

6. The method according to any one of claims 1 to 5, characterized in that: The method is applied to a first terminal device, which has a sensing capability but does not have a channel encoding and decoding and channel modulation and demodulation capability.

7. A synchronization method, characterized in that: The method comprises: Receiving a first sidelink synchronization signal block S-SSB from a first terminal device; A second S-SSB is sent to the first terminal device according to the signal quality of the first S-SSB; wherein the second S-SSB indicates second synchronization information and the synchronization source indicating the second synchronization information is a second synchronization source, and the second synchronization source is one of the following: a global navigation satellite system GNSS, an access network device, or a terminal device synchronized with the GNSS or the access network device; the first S-SSB and the second S-SSB are sequence-based SSBs.

8. The method according to claim 7, characterized in that Sending a second S-SSB to the first terminal device according to the signal quality of the first S-SSB includes: When the signal quality of the first S-SSB is greater than or equal to a first threshold, the second S-SSB is sent to the first terminal device.

9. The method according to claim 7 or 8, characterized in that: The second S-SSB includes indication information, where the indication information is used to indicate that the synchronization source of the second synchronization information is the second synchronization source, and the indication information is located in the main information block of the second S-SSB.

10. The method according to claim 7 or 8, characterized in that: The second S-SSB includes a side link synchronization signal SLSS, and when a sequence corresponding to the SLSS is in a preset sequence set, it indicates that the synchronization source of the second synchronization information is the second synchronization source.

11. The method according to any one of claims 7 to 10, characterized in that: Before receiving the first S-SSB from the first terminal device, the method further includes: receiving the second synchronization information from the second synchronization source; Synchronize with the second synchronization source according to the second synchronization information.

12. The method according to any one of claims 7 to 11, characterized in that: The first S-SSB indicates first synchronization information, and the synchronization source of the first synchronization information is the first synchronization source, and the first synchronization source is the internal clock of the first terminal device or the third terminal device. The first terminal device and the third terminal device have perception capabilities but do not have channel encoding and decoding and channel modulation and demodulation capabilities; the priority of the first synchronization source is lower than the priority of the second synchronization source.

13. The method according to any one of claims 7 to 12, characterized in that: The first terminal device has perception capability but does not have channel encoding and decoding and channel modulation and demodulation capabilities.

14. The method according to any one of claims 7 to 13, characterized in that: The method is applied to a second terminal device, which has a sensing capability as well as channel coding and decoding and channel modulation and demodulation capabilities.

15. A synchronization method, characterized in that: The method is applied to a communication system, the communication system comprising a first terminal device and a second terminal device; the method comprises: The first terminal device sends a first sidelink synchronization signal block S-SSB, where the first S-SSB indicates first synchronization information, and the first S-SSB is a sequence-based SSB; The second terminal device receives the first S-SSB from the first terminal device; The second terminal device sends a second S-SSB to the first terminal device according to the signal quality of the first S-SSB; wherein the second S-SSB indicates second synchronization information and the synchronization source indicating the second synchronization information is a second synchronization source, and the second synchronization source is one of the following: a global navigation satellite system GNSS, an access network device, or a terminal device synchronized with the GNSS or the access network device; the second S-SSB is a sequence-based SSB; The first terminal device receives the second S-SSB from the second terminal device, and updates synchronization information from the first synchronization information to the second synchronization information.

16. The method according to claim 15, characterized in that The second S-SSB includes indication information, where the indication information is used to indicate that the synchronization source of the second synchronization information is the second synchronization source, and the indication information is located in the main information block of the second S-SSB.

17. The method according to claim 15, characterized in that The second S-SSB includes a side link synchronization signal SLSS, and when a sequence corresponding to the SLSS is in a preset sequence set, it indicates that the synchronization source of the second synchronization information is the second synchronization source.

18. The method according to any one of claims 15 to 17, characterized in that: The synchronization source of the first synchronization information is the first synchronization source, which is the internal clock of the first terminal device or the third terminal device. The first terminal device and the third terminal device have perception capabilities but do not have channel encoding and decoding and channel modulation and demodulation capabilities.

19. The method according to claim 18, characterized in that The priority of the first synchronization source is lower than the priority of the second synchronization source.

20. The method according to any one of claims 15 to 19, characterized in that: The second terminal device sending a second S-SSB to the first terminal device according to the signal quality of the first S-SSB, including: When the signal quality of the first S-SSB of the second terminal device is greater than or equal to a first threshold, the second S-SSB is sent to the first terminal device.

21. The method according to any one of claims 15 to 20, characterized in that: Before receiving the first S-SSB from the first terminal device, the second terminal device also receives the second synchronization information from the second synchronization source and synchronizes with the second synchronization source according to the second synchronization information.

22. The method according to any one of claims 15 to 21, characterized in that: The synchronization source of the first synchronization information is the first synchronization source; and the first terminal device updates the synchronization information from the first synchronization information to the second synchronization information, including: The first terminal device updates the synchronization information from the first synchronization information to the second synchronization information according to a priority order of synchronization sources; the priority order of the synchronization sources includes that the priority of the second synchronization source is higher than the priority of the first synchronization source.

23. The method according to any one of claims 15 to 22, characterized in that: The first terminal device has perception capability but does not have channel encoding and decoding and channel modulation and demodulation capabilities.

24. A communication device, characterized in that: The communication device comprises a processor; the processor is used to run a computer program or instruction so that the communication device executes the method according to any one of claims 1 to 6, or so that the communication device executes the method according to any one of claims 7 to 14.

25. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions or programs. When the computer instructions or programs are executed on a computer, the method according to any one of claims 1 to 6 is executed, or the method according to any one of claims 7 to 14 is executed.

26. A computer program product, characterized in that The computer program product includes computer instructions; when part or all of the computer instructions are run on a computer, the method according to any one of claims 1 to 6 is executed, or the method according to any one of claims 7 to 14 is executed.

27. A communication system, characterized in that: The communication system includes a first terminal device and a second terminal device; the first terminal device is used to implement the method according to any one of claims 1-6, and the second terminal device is used to implement the method according to any one of claims 7-14.

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