Communication method and apparatus

Abstract

A communication method and apparatus, belonging to the field of communication, are disclosed. In this method, by designing a first pattern and a second pattern, it is ensured that after S time-domain units are cyclically moved any number of time-domain units across P time-domain units, at least one time-domain unit still belongs to R time-domain units. Thus, regardless of the time-domain unit offset between the transmitting time-domain unit of the terminal device and the receiving time-domain unit of the network device, at least a portion of the preamble transmitted by the terminal device using the second pattern can always be detected by the network device. Therefore, this scheme avoids the situation where the preamble transmitted by the terminal device cannot be detected by the network device. Furthermore, the network device can send first information for time synchronization based on the detected first preamble, thereby achieving time synchronization. It is evident that this scheme can ensure that the network device detects the preamble, thereby improving the efficiency of time synchronization between the network device and the terminal device.

Description

Technical Field

[0001] This application relates to the field of communications, and more specifically, to a communication method and apparatus. Background Technology

[0002] In non-terrestrial network (NTN) systems, network equipment deployed on satellites (e.g., access network equipment, core network equipment, or management plane equipment) can transmit signals to terminal devices. Terminal devices can also transmit signals to network equipment deployed on satellites. Compared to terrestrial communication systems, network equipment and terminal devices in NTN systems are geographically farther apart, resulting in greater transmission latency. This makes time synchronization between network equipment and terminal devices more challenging.

[0003] Improving the efficiency of time synchronization between network devices and terminal devices is an urgent problem to be solved. Summary of the Invention

[0004] This application provides a communication method and apparatus that can improve the efficiency of time synchronization between network devices and terminal devices.

[0005] Firstly, a communication method is provided. The method provided in the first aspect can be executed by a first communication device. Unless otherwise specified, the first communication device in this application can be a network device, a component applicable to a network device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing some or all of the functions of a network device. For ease of description, the following description assumes that the first communication device is a network device.

[0006] For example, the method includes: detecting a first preamble based on a first pattern; and sending first information based on the first preamble, the first information being used for time synchronization between the network device and the terminal device.

[0007] The first preamble can be part or all of the preamble transmitted using the second pattern. The second pattern can be used to indicate that S preambles are transmitted in S time-domain units out of P time-domain units, where P is a positive integer and S is a positive integer less than or equal to P. For example, the S time-domain units can be part or all of the P time-domain units.

[0008] As an example, based on the second pattern, the terminal device can transmit S preambles in S time-domain units respectively. The first preamble can be some or all of the S preambles.

[0009] The first pattern can be used to indicate preamble detection on R time-domain units out of the P time-domain units, where R is a positive integer less than or equal to P. For example, the network device performs preamble detection on the aforementioned R time-domain units. As an example, the network device may detect the preamble on some time-domain units out of the R time-domain units, while not detecting it on others. In this case, the preambles detected by the network device can be collectively referred to as the first preamble. As another example, the network device may detect the preamble on all time-domain units out of the R time-domain units; these preambles can be collectively referred to as the first preamble.

[0010] Wherein, after the S time-domain units are cyclically moved any number of time-domain units over the P time-domain units, at least one time-domain unit overlaps with the R time-domain units. That is, regardless of how many time-domain units are offset between the receiving time-domain unit of the terminal device and the transmitting time-domain unit of the network device, at least a portion of the S preambles transmitted by the terminal device over the S time-domain units will fall into the R time-domain units, i.e., at least a portion of the preambles can be detected by the network device based on the first pattern.

[0011] Based on the above scheme, by designing the first and second patterns, it is ensured that after the S time-domain units are cyclically moved any number of time-domain units across the P time-domain units, at least one time-domain unit still belongs to the R time-domain units. Thus, regardless of the time-domain unit offset between the terminal device's transmitting time-domain unit and the network device's receiving time-domain unit, at least a portion of the preamble transmitted by the terminal device using the second pattern will always be detectable by the network device. Therefore, the above scheme avoids the situation where the preamble transmitted by the terminal device cannot be detected by the network device. Furthermore, the network device can send first information for time synchronization based on the detected first preamble, thereby achieving time synchronization. It is evident that this scheme can ensure that the network device detects the preamble, thereby improving the efficiency of time synchronization between the network device and the terminal device.

[0012] In some implementations, the P time-domain units are N*K time-domain units in N time-domain unit groups, where each of the N time-domain unit groups includes K time-domain units, and N and K are positive integers. The method further includes: determining a first offset based on the time-domain unit group to which the time-domain unit detecting the first preamble belongs and N*K third patterns. The first offset indicates the number of time-domain units offset between the receiving time-domain unit of the network device and the transmitting time-domain unit of the terminal device. The third pattern indicates the number of preambles detected in each of the N time-domain unit groups, and any two of the N*K third patterns are different.

[0013] Based on the above scheme, the network device can determine the number of preambles detected in each of the N time-domain unit groups based on the time-domain unit group to which the detected first preamble belongs, thereby obtaining the third pattern corresponding to the first preamble. Any two of the N*K third patterns are different, and each of the N*K third patterns corresponds one-to-one with N*K time-domain unit offsets between the network device's receiving time-domain unit and the terminal device's transmitting time-domain unit across P time-domain units. Therefore, the network device can uniquely determine the number of time-domain units offset between the network device's receiving time-domain unit and the terminal device's transmitting time-domain unit, i.e., the first offset, based on the third pattern corresponding to the first preamble and the aforementioned correspondence. The above scheme designs the first and second patterns to ensure that any two of the N*K third patterns are different. In this way, the network device can determine the number of time domain units offset between the network device's receiving time domain unit and the terminal device's transmitting time domain unit in one step, based on the time domain unit group to which the detected first preamble time domain unit belongs, and N*K third patterns. This helps to quickly achieve pattern period-level time synchronization between the network device and the terminal device. The length of one pattern period can be the length of P time domain units or the length of N time domain unit groups.

[0014] In some implementations, the first information includes indication information of the first offset.

[0015] In some implementations, the method further includes: when a check sequence is detected on the P time-domain units, determining a second offset based on the position of the P time-domain units in the radio frame, the second offset indicating the number of pattern periods offset between the pattern period of the network device and the pattern period of the terminal device in the radio frame. The length of one pattern period can be the length of P time-domain units, i.e., the length of a group of N time-domain units.

[0016] Based on the above scheme, if a network device detects P time-domain units, it indicates that time synchronization at the radio frame level has not been achieved between the network device and the terminal device. For example, assuming a radio frame consists of two pattern periods, and the parity check sequence is transmitted in the first pattern period (i.e., the first half of the frame), while the network device detects the parity check sequence in the second pattern period (i.e., the second half of the frame), the network device can determine the number of pattern periods offset between its pattern period and the terminal device's pattern period, i.e., the second offset. This scheme helps the network device and the terminal device achieve time synchronization at the radio frame level.

[0017] In some implementations, the first information includes indication information for the second offset.

[0018] In some implementations, the method further includes sending the identifier of the first preamble when a check sequence is detected on the P time-domain units.

[0019] Based on the above scheme, if the network device detects P time-domain units, it indicates that time synchronization at the radio frame level has been achieved between the network device and the terminal device. For example, assuming a radio frame consists of two pattern periods, and the parity check sequence is sent in the first pattern period (i.e., the first half of the frame), and the network device detects the parity check sequence in the first pattern period of the radio frame, then the network device can determine that time synchronization at the radio frame level has been achieved between the network device and the terminal device, and thus further send the preamble identifier to trigger the subsequent random access procedure.

[0020] In some implementations, the time-domain unit is a symbol, and / or the time-domain unit group is a slot.

[0021] Secondly, a communication method is provided. The method provided in this application can be executed by a second communication device. Unless otherwise specified, the second communication device in this application can be a terminal device, a component applicable to a terminal device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing some or all of the functions of the terminal device. For ease of description, the following description assumes the second communication device is a terminal device.

[0022] For example, the method includes: based on a second pattern, sending S preambles in S time-domain units out of P time-domain units, where P is a positive integer and S is a positive integer less than or equal to P; and receiving first information for time synchronization between the network device and the terminal device.

[0023] In some implementations, the P time-domain units are N*K time-domain units in a group of N time-domain units, where each of the N time-domain unit groups includes K time-domain units, and N and K are positive integers. The method further includes: receiving indication information of a first offset, the first offset indicating the number of time-domain units offset between the receiving time-domain unit of the network device and the transmitting time-domain unit of the terminal device; and transmitting a second preamble based on the first offset and the second pattern.

[0024] In some implementations, the indication information of the first offset is carried in the first information.

[0025] In some implementations, the method further includes: transmitting a check sequence on time domain units other than the S time domain units across the P time domain units; receiving indication information of a second offset, the second offset indicating the number of pattern periods offset between the pattern period of the network device and the pattern period of the terminal device on the radio frame; and transmitting a third preamble based on the second offset and the second pattern. The length of one pattern period can be the length of P time domain units, i.e., the length of a group of N time domain units.

[0026] In some implementations, the method further includes: transmitting a verification sequence on the time domain units other than the S time domain units on the P time domain units; receiving an identifier of a first preamble, the first preamble belonging to the S preambles; and transmitting a random access message based on the identifier of the first preamble.

[0027] In some implementations, the indication information of the second offset is carried in the first information, and / or the identifier of the first preamble is carried in the first information.

[0028] In some implementations, the time-domain unit is a symbol, and / or the time-domain unit group is a time slot.

[0029] Thirdly, a communication device is provided, including processing circuitry (or a processor) and an input / output interface (also referred to as an interface circuit), the input / output interface being used for inputting and / or outputting signals, the processing circuitry being used to perform the first aspect and any possible method of the first aspect, or the processing circuitry being used to perform the second aspect and any possible method of the second aspect.

[0030] In some implementations, the processing circuitry is used to communicate with other devices via an interface circuitry and to perform the first aspect and any possible method of the first aspect, or to perform the second aspect and any possible method of the second aspect.

[0031] Fourthly, a communication device is provided. This communication device may include units, modules, or means for performing the functions of the communication device.

[0032] In some implementations, the communication device may include modules, units, or means for performing the methods / operations / steps / actions described in the first aspect and any possible implementation of the first aspect. These modules, units, or means may be hardware circuits, software, or a combination of hardware circuits and software.

[0033] For example, the device includes a processing unit and a transceiver unit. The processing unit is used to detect a first preamble based on a first pattern; the transceiver unit is used to send first information based on the first preamble, the first information being used for time synchronization between the network device and the terminal device; wherein the first preamble is sent with a second pattern, the second pattern being used to indicate that S preambles are sent respectively in S time domain units out of P time domain units, where P is a positive integer and S is a positive integer less than or equal to P; wherein the first pattern is used to indicate that preamble detection is performed in R time domain units out of the P time domain units, where R is a positive integer less than or equal to P; wherein after the S time domain units are cyclically moved any number of time domain units in the P time domain units, at least one time domain unit overlaps with the R time domain units.

[0034] In some implementations, the P time-domain units are N*K time-domain units in N time-domain unit groups, where each of the N time-domain unit groups includes K time-domain units, and N and K are positive integers. The processing unit is further configured to: determine a first offset based on the time-domain unit group to which the time-domain unit that detected the first preamble belongs and N*K third patterns. The first offset indicates the number of time-domain units offset between the receiving time-domain unit of the network device and the transmitting time-domain unit of the terminal device. The third pattern indicates the number of preambles detected in each of the N time-domain unit groups, and any two of the N*K third patterns are different.

[0035] In some implementations, the processing unit is further configured to: upon detecting a check sequence on the P time-domain units, determine a second offset based on the position of the P time-domain units in the radio frame, the second offset indicating the number of pattern periods offset between the pattern period of the network device and the pattern period of the terminal device in the radio frame. The length of one pattern period can be the length of P time-domain units, i.e., the length of a group of N time-domain units.

[0036] In some implementations, when a check sequence is detected on the P time-domain units, the transceiver unit is also used to send the identifier of the first preamble.

[0037] In some implementations, the communication device may include modules, units, or means for performing the methods / operations / steps / actions described in the second aspect and any possible implementation of the second aspect, which may be hardware circuits, software, or a combination of hardware circuits and software.

[0038] For example, the device includes a transceiver unit. The transceiver unit is configured to: transmit S preambles in S time-domain units out of P time-domain units based on a second pattern, where P is a positive integer and S is a positive integer less than or equal to P; and receive first information for time synchronization between the network device and the terminal device.

[0039] In some implementations, the P time-domain units are N*K time-domain units in a group of N time-domain units, where each of the N time-domain unit groups includes K time-domain units, and N and K are positive integers. The transceiver unit is further configured to: receive indication information of a first offset, which indicates the number of time-domain units offset between the receiving time-domain unit of the network device and the transmitting time-domain unit of the terminal device; and transmit a second preamble based on the first offset and the second pattern.

[0040] In some implementations, the transceiver unit is further configured to: transmit a check sequence on time domain units other than the S time domain units across the P time domain units; receive indication information of a second offset, the second offset indicating the number of pattern periods offset between the pattern period of the network device and the pattern period of the terminal device on the radio frame; and transmit a third preamble based on the second offset and the second pattern. The length of one pattern period can be the length of P time domain units, i.e., the length of a group of N time domain units.

[0041] In some implementations, the transceiver unit is also used to: transmit a check sequence on the time domain units other than the S time domain units on the P time domain units; receive the identifier of the first preamble, which belongs to the S preambles; and send a random access message based on the identifier of the first preamble.

[0042] Fifthly, a computer-readable storage medium is provided that stores a computer program or instructions that, when executed, cause the first aspect and any possible method of the first aspect to be performed (or implemented), or cause the second aspect and any possible method of the second aspect to be performed (or implemented).

[0043] In a sixth aspect, a computer program product is provided, comprising a computer program or instructions that, when executed, cause the first aspect and any possible method of the first aspect to be performed (or implemented), or cause the second aspect and any possible method of the second aspect to be performed (or implemented).

[0044] A seventh aspect provides a communication device, including a processor for executing (or implementing) any of the possible methods of the first aspect above, or for executing (or implementing) any of the possible methods of the second aspect above, by executing a computer program (or computer-executable instructions) stored in a memory, and / or by logic circuitry.

[0045] In one possible implementation, the device also includes a memory. In another possible implementation, the processor and memory are integrated together. In yet another possible implementation, the memory is located outside the device. The processor may include one or more processors.

[0046] In some possible implementations, the memory may be used to store part or all of the computer programs or instructions necessary to implement the functions involved in the first aspect above.

[0047] In some possible implementations, the memory may be used to store part or all of the computer programs or instructions necessary to implement the functions involved in the second aspect above.

[0048] In one possible implementation, the communication device further includes a communication interface for communicating with other devices, such as transmitting or receiving data and / or signals. Exemplarily, the communication interface may be a transceiver, circuit, bus, module, input / output interface, or other types of communication interface.

[0049] In one implementation, the communication device of the third, fourth or seventh aspect mentioned above can be a terminal device or a communication module in a terminal device, or a chip or chip system in a terminal device.

[0050] In one implementation, the communication device of the third, fourth or seventh aspect mentioned above can be a network device or a communication module in a network device, or a chip or chip system in a network device.

[0051] Eighthly, a chip is provided, including a processor for calling a computer program or computer instructions in a memory to cause the processor to execute or implement any of the implementations of the first aspect above, or to cause the processor to execute or implement any of the implementations of the second aspect above.

[0052] In some implementations, the processor is coupled to the memory via an interface.

[0053] A ninth aspect provides a communication system, including a first communication device and a second communication device. The first communication device is configured to execute the first aspect and any possible implementation thereof, and the second communication device is configured to execute the second aspect and any possible implementation thereof.

[0054] The description of the beneficial effects of any of the second to ninth aspects can be referred to the description of the beneficial effects of the first aspect. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of a communication system.

[0056] Figure 2 This is a schematic diagram of another communication system.

[0057] Figure 3 This is a schematic flowchart of the random access method.

[0058] Figure 4 This is a schematic diagram of the contents of a RAR file.

[0059] Figure 5 This is a schematic flowchart of a communication method provided in an embodiment of this application.

[0060] Figure 6 This is a schematic flowchart of another communication method 600 provided in an embodiment of this application.

[0061] Figure 7 This is a schematic block diagram of a communication device provided in an embodiment of this application.

[0062] Figure 8 This is a schematic diagram of another communication device provided in an embodiment of this application.

[0063] Figure 9 This is a schematic diagram of a chip system provided in an embodiment of this application.

[0064] Figure 10 This is a schematic diagram of another chip system provided in an embodiment of this application. Detailed Implementation

[0065] In this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0066] I. In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone, where A and B can be singular or plural. In the textual description of this application, the character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, and c can mean: a, or, b, or, c, or, a and b, or, a and c, or, b and c, or, a, b, and c. Here, a, b, and c can each be single or multiple.

[0067] II. In this application, the terms "first," "second," and various numerical designations (e.g., #1, #2, etc.) indicate distinctions made for ease of description and are not intended to limit the scope of the embodiments of this application. For example, the first drawing and the second drawing are used to distinguish different drawings, rather than to describe a specific order or sequence of the drawings. It should be understood that such descriptions can be interchanged where appropriate to describe solutions other than those in the embodiments of this application.

[0068] Third, in this application, descriptions such as "when," "under the circumstances," and "if" all refer to the device making corresponding processing under certain objective circumstances, and are not time-limited, nor do they require the device to make a judgment action when implementing it, nor do they imply any other limitations.

[0069] IV. In this application, "instruction" or "for instruction" can include both direct (or explicit) and indirect (or implicit) instruction. When describing instruction information as indicating A, it can include whether the instruction information directly or indirectly indicates A, but does not necessarily mean that the instruction information carries A. For example, in the case of indirect (or implicit) instruction, the receiving end of the instruction information can obtain A based on the parameters indicated by the instruction information, combined with other rules or parameters, or through deduction.

[0070] V. The indication methods involved in the embodiments of this application should be understood to cover various methods that enable the party to be indicated to obtain the information to be indicated. The information to be indicated can be sent as a whole or divided into multiple sub-information and sent separately. Moreover, the sending period and / or sending time of these sub-information can be the same or different. This application does not limit the sending method, for example.

[0071] VI. In this application, "protocol" can refer to standard protocols in the field of communications, such as 5G protocols, new radio (NR) protocols, and related protocols applied in future communication systems; this application does not limit this term. "Predefined" can include predefined terms, such as protocol definitions. "Preconfiguration" can be implemented by pre-storing corresponding codes, tables, or other means that can be used to indicate relevant information in the device; this application does not limit the implementation method.

[0072] VII. In this application, "communication" can also be described as "data transmission," "information transmission," "data processing," etc. "Transmission" includes "sending" and / or "receiving." For example, transmission can be uplink transmission, such as a terminal device sending a signal to a network device; transmission can also be downlink transmission, such as a network device sending a signal to a terminal device; transmission can also be sidelink transmission, such as a terminal device sending a signal to another terminal device. For example, "transmission" can be air interface level transmission, or it can be signal transmission from a chip input (I) / output (O) port, rather than air interface level transmission.

[0073] 8. In this application, terms such as “message”, “information”, “signal” or “information element (IE)” can be used interchangeably. There are no restrictions on the name of the message or information, as long as it can achieve the corresponding function.

[0074] 9. "Sending information to XX (device)" can be understood as the destination of the information being that device. This can include sending information directly or indirectly to that device. "Receiving information from XX (device), or receiving information from XX (device)" can be understood as the source of the information being that device. This can include receiving information directly or indirectly from that device. Information may undergo necessary processing between the source and destination, such as format changes, but the destination can understand the valid information from the source. Similar expressions in this application can be understood in a similar way, and will not be repeated here. Furthermore, "sending" can also be understood as the "output" of the chip interface, and "receiving" can also be understood as the "input" of the chip interface. In other words, "sending" or "receiving" can occur between devices, for example, between network devices and terminal devices via an air interface. "Sending" or "receiving" can also occur within a device, for example, between components, modules, chips, software modules, or hardware modules within the device via a bus, wiring, or interface.

[0075] 10. In this application, terms such as "exemplarily" and "for example" are used to indicate examples, illustrations, or descriptions to present concepts in a specific manner. Any embodiment or design described as an "example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. In the embodiments of this application, the terms "of," "corresponding (relevant)," "corresponding," and "associated" may sometimes be used interchangeably, and it should be noted that their intended meanings are consistent unless their distinctions are emphasized.

[0076] XI. In this application, configuration can be signaling configuration or can be described as configuring signaling. For example, signaling configuration includes configuration using signaling sent by network devices, which can be radio resource control (RRC) messages, downlink control information (DCI) messages, or system information blocks (SIBs). Another example is signaling configuration between network devices. These network devices can include access network devices, core network devices, or management plane devices, etc. Optionally, signaling configuration can also be configured to terminal devices or network devices using pre-configured signaling, or configured to terminal devices or network devices through pre-configuration. Here, pre-configuration refers to defining or configuring the values ​​of corresponding parameters in advance using a protocol, and storing them in the terminal device or network device during communication. Pre-configured messages can be modified or updated when the terminal device or network device is connected to the network.

[0077] 12. This application will present various aspects, embodiments, or features relating to systems that may include multiple devices, components, modules, etc. Each system may include devices, components, modules, etc., other than those illustrated, and / or may not include all and all of the devices, components, modules, etc. discussed in conjunction with the accompanying drawings.

[0078] Thirteen, the business scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. As those skilled in the art will know, with the emergence of new business scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0079] XIV. In the various embodiments of this application, the sequence number of each step does not imply the order of execution. The execution order of each step should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The terms "comprising," "including," "having," and their variations all mean "including but not limited to," unless otherwise specifically emphasized.

[0080] The technical solutions of this application embodiment can be applied to various communication systems, including but not limited to: Long Term Evolution (LTE) systems, NR systems, and 5G (5G) systems. th This includes various mobile communication systems such as 5G, narrowband Internet of Things (NB-IoT), enhanced machine-type communication (eMTC), enhanced mobile broadband (eMBB), ultra-reliable low latency communications (URLLC), satellite communication systems, LTE-machine-to-machine (LTE-M) systems, and other systems that evolve after 5G, such as future mobile communication systems.

[0081] The following describes the solutions of embodiments of this application with reference to the accompanying drawings.

[0082] Figure 1 This is a schematic diagram of a communication system 100. (For example...) Figure 1 As shown, the communication system 100 includes a wireless access network 110 and a core network 120. Optionally, the communication system 100 may also include an Internet 130. The wireless access network 110 may include at least one access network device (such as...). Figure 1 111a and 111b in the above), may also include at least one terminal device (such as Figure 1(112a-112j in the original text). The terminal device connects to the access network device wirelessly. The access network device connects to the core network 120 wirelessly or via a wired connection. The core network 120 may include one or more core network devices. The core network device and the access network device may be independent physical devices, or the functions of the core network device and the logical functions of the access network device may be integrated on the same physical device, or a single physical device may integrate some of the functions of the core network device and some of the functions of the access network device. Terminal devices and access network devices can be interconnected via wired or wireless means. Terminal devices can communicate wirelessly with each other, with each other, and with each other via air interface resources. For example, air interface resources may include at least one of time-domain resources, frequency-domain resources, code resources, and spatial resources. Figure 1 This is a schematic diagram. The communication system 100 may also include other access network equipment, such as wireless repeater equipment and wireless backhaul equipment. Figure 1 It is not shown in the middle.

[0083] Access network equipment can be any device with wireless transceiver capabilities. For example, access network equipment can be a base station used to connect terminal devices to a radio access network (RAN). Access network equipment is sometimes also referred to as access network element, access network node, RAN node, or RAN. It is understood that the names of devices with access network equipment functionality may differ in systems employing different wireless access technologies. For ease of description, devices that provide wireless communication access capabilities to terminal devices can be collectively referred to as base stations or RAN equipment.

[0084] Access network equipment can be used for the 3rd Generation Partnership Project (3GPP). rd Cellular systems related to the Generation Partnership Project (3GPP), such as 4G mobile communication systems, 5G mobile communication systems, non-terrestrial network (NTN) systems, or future communication systems, etc. Access network equipment can also be access network equipment in open RAN (O-RAN or ORAN), cloud radio access network (CRAN), or wireless fidelity (Wi-Fi) systems, or access network equipment in communication systems that integrate two or more of the above systems.

[0085] When the access network device is an access network device in an NTN system, the access network device can be in regeneration mode or transparent transmission mode, and this application does not limit it.

[0086] For example, an NTN system may be referred to as an NTN network, a satellite communication system, a satellite communication network, or other names.

[0087] For example, access network equipment includes, but is not limited to: various forms of macro base stations (such as...) Figure 1 111a), micro base stations or indoor stations (such as Figure 1 (111b) picocells, small cells, balloon stations, relay stations, access points, etc. Access network equipment may include evolved node B (eNB or eNodeB) in LTE, access point (AP), wireless relay node, wireless backhaul node, transmission point (TRP or TP) or transmission reception point (TRP) in wireless fidelity (Wi-Fi) systems, terminal equipment that implements network functions in device-to-device (D2D) or vehicle-to-everything (V2X) systems, next-generation base station nodes (gNB) or transmission points (TRP or TP) in 5G systems, one or a group of antenna panels (including multiple antenna panels) of base stations in 5G systems, network nodes constituting gNB or transmission points, such as baseband unit (BBU) or distributed unit (DU), access network equipment, servers or vehicle-mounted equipment in networks evolved after 5G, and satellites or base stations deployed on satellites.

[0088] Optionally, access network equipment may also include servers, wearable devices, vehicles, or in-vehicle equipment. For example, access network equipment in V2X technology can be a roadside unit (RSU).

[0089] Access network equipment can also be modules or units that perform some of the functions of a base station. For example, it can be a central unit (CU) or a DU.

[0090] In this embodiment, the apparatus for implementing the functions of the access network device can be the access network device itself, or it can be an apparatus capable of supporting the access network device in implementing the functions, such as a chip system, which can be installed in the access network device. The chip system can be composed of chips, or it can include chips and other discrete components.

[0091] In another possible scenario, multiple access network devices collaborate to assist the terminal in achieving wireless access, with each access network device performing a portion of the base station's functions. For example, the access network devices can be CU, DU, CU (control plane, CP), CU (user plane, UP), or radio unit (RU), etc. CU and DU can be configured separately or included in the same network element, such as in a BBU. RU can be included in radio equipment or radio units, such as in a remote radio unit (RRU), active antenna unit (AAU), or remote radio head (RRH).

[0092] In different systems, CU (or CU-CP and CU-UP), DU, or RU may have different names, but those skilled in the art will understand their meaning. For example, in an open radio access network (O-RAN) system, CU can also be called O-CU (open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU. For ease of description, this application uses CU, CU-CP, CU-UP, DU, and RU as examples. Any of the units among CU (or CU-CP, CU-UP), DU, and RU in this application can be implemented through software modules, hardware modules, or a combination of software modules and hardware modules. The embodiments of this application do not limit the specific technology or specific device form used in the access network equipment.

[0093] Terminal equipment can be a device that provides voice and / or data connectivity to a user; alternatively, it can be an entity on the user side used to receive or transmit signals. Terminal equipment can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; it can also be deployed on water (such as on ships); and it can be deployed in the air (e.g., on airplanes, balloons, and satellites). Terminal equipment can also be referred to as user equipment (UE), access terminal, terminal, subscriber unit, user station, mobile station, mobile station (MS), mobile terminal (MT), remote station, remote terminal, mobile device, user terminal, wireless network equipment, user agent, or user device. In this application embodiment, terminal devices include, but are not limited to: cellular phones, mobile phones, wireless data cards, wireless modems, tablets, laptop computers, notebook computers, handheld computers, mobile internet devices (MIDs), computers with wireless transceiver capabilities, cordless phones, session initiation protocol (SIP) phones, smartphones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handsets with wireless communication capabilities, computing devices or other devices connected to wireless modems, in-vehicle devices (e.g., cars, bicycles, electric vehicles, airplanes, ships, trains, high-speed trains, etc.), wearable devices (e.g., smartwatches, smart bracelets, pedometers, smart glasses, etc.), satellite terminals, terminal devices in the Internet of Things or the Internet of Vehicles, as well as any form of terminal in future networks, relay user equipment, or terminals in future evolved public land mobile networks (PLMNs), etc.Terminal devices can also be virtual reality (VR) devices, augmented reality (AR) devices, smart point-of-sale (POS) machines, customer-premises equipment (CPE), light user equipment (UE), reduced capability user equipment (REDCAPUE), machine type communication (MTC) terminals, terminal devices in industrial control, terminal devices in self-driving, terminal devices in telemedicine, terminal devices in smart grids, wireless terminals in transportation safety, terminal devices in smart cities, terminal devices in smart homes, tactile terminal devices, smart home devices (e.g., refrigerators, televisions, air conditioners, electricity meters, etc.), smart robots, robotic arms, workshop equipment, wireless terminals in self-driving, or flying devices (e.g., smart robots, hot air balloons, drones, airplanes), etc. The terminal device can also be a vehicle device, such as a complete vehicle device, an in-vehicle module, an in-vehicle chip, an on-board unit (OBU), or a telematics box (T-BOX). The terminal device can also be other devices with terminal functions; for example, it can be a device that functions as a terminal in D2D communication. This application does not limit the scope of the embodiments.

[0094] In this application embodiment, the device for implementing the functions of the terminal device can be the terminal device itself, or it can be any device capable of supporting the terminal device in implementing the functions, such as a chip or chip system. This device can be installed in the terminal device. The chip system can consist of chips or include chips and other discrete components. In the technical solution of this application embodiment, the device for implementing the functions of the terminal device is referred to as the terminal device, which can also be called a terminal. The following description may use a UE (User Equipment) as an example to illustrate the technical solution provided in this application embodiment.

[0095] The roles of base stations and terminals can be relative, for example, Figure 1The helicopter or drone 112i can be configured as a mobile base station. For terminals 112j that access the wireless access network 110 via 112i, terminal 112i is a base station; however, for base station 111a, 112i is a terminal, meaning that 111a and 112i communicate via a wireless air interface protocol. Of course, 111a and 112i can also communicate via a base station-to-base station interface protocol; in this case, relative to 111a, 112i is also a base station. Therefore, both base stations and terminals can be collectively referred to as communication devices. Figure 1 111a and 111b in the diagram can be referred to as communication devices with base station functionality. Figure 1 The 112a-112j in the text can be referred to as communication devices with terminal functions.

[0096] Access network devices and terminal devices can communicate via wireless links. The transmission link from the access network device to the terminal device can be called a downlink (DL) or downlink channel, used for transmitting downlink signals. The transmission link from the terminal device to the access network device can be called an uplink (UL) or uplink channel, used for transmitting uplink signals. The transmission link from one terminal device to another can be called a sidelink (SL) or sidelink channel, used for transmitting sidelink signals.

[0097] Communication between access network devices and terminal devices can follow a specific protocol layer structure. This protocol layer may include a control plane protocol layer and a user plane protocol layer. The control plane protocol layer may include at least one of the following: radio resource control (RRC) layer, packet data convergence protocol (PDCP) layer, radio link control (RLC) layer, media / medium access control (MAC) layer, or physical (PHY) layer, etc. The user plane protocol layer may include at least one of the following: service data adaptation protocol (SDAP) layer, PDCP layer, RLC layer, MAC layer, or physical layer, etc.

[0098] For example, the RRC layer of the access network device and the RRC layer of the terminal device can exchange RRC signaling or other messages. As another example, the PHY layer of the access network device can send a physical downlink control channel (PDCCH) or a physical downlink shared channel (PDSCH) to the PHY layer of the terminal device, and so on. Similarly, the PHY layer of the terminal device can send a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH) to the PHY layer of the access network device, and so on.

[0099] Figure 2 This is a schematic diagram of another communication system. For example... Figure 2 As shown, the communication system includes network equipment and at least one terminal device. Figure 2 This is a schematic diagram. The communication system may also include other network devices, more terminal devices, or core network equipment. Figure 2 It is not shown in the middle.

[0100] As an example, Figure 2 The network equipment in this context can be a base station deployed on a satellite (referred to as a "satellite base station"). For example, a satellite base station can transmit downlink data to a terminal device. Exemplarily, the downlink data can be encoded using channel coding, and the channel-coded downlink data is then transmitted to the terminal device after constellation modulation. Similarly, a terminal device can transmit uplink data to a satellite base station. Exemplarily, the uplink data can be encoded using channel coding, and the encoded uplink data is then transmitted to the satellite base station after constellation modulation.

[0101] To better understand the embodiments of this application, the following is an introduction to the technical terms involved in the embodiments of this application.

[0102] 1. Random Access

[0103] Random access can be used to solve the time-frequency synchronization problem between terminal devices and network devices, and to allocate uplink resources to terminal devices for further communication. Depending on the different requirements of the access process, random access can be divided into contention-based random access (CBRA) and contention-free random access (CFRA).

[0104] Figure 3This is a schematic flowchart illustrating the random access method. Among them, Figure 3 (a) shows a schematic flowchart of the four-step random access method. See also Figure 3 In (a), the terminal device can send message 1 (MSG1 or Msg1) to the network device. This Msg1 may include a random access (RA) preamble. For example, the RA preamble may be called a preamble, PRACH signaling, PRACH information, PRACH message, PRACH sequence, sequence, preamble sequence, or other names. The terminal device can select a preamble from the set of preambles and send that preamble to the network device, that is, send Msg1 to the network device.

[0105] For example, after detecting the preamble, the network device can send a random access response (RAR) message to the terminal device.

[0106] As an example, RAR may include at least one of the following: the identifier of the preamble received by the network side, time advance (TA) information, backoff indicator, radio network temporary identifier (RNTI) (temporary cell RNTI, TC-RNTI), or indication information for scheduling uplink resources for the terminal device to send message 3 (MSG3 or Msg3).

[0107] The aforementioned preamble identifier can be a random access preamble identifier (RAPID). The indication information used to schedule the uplink resources for the terminal device to send Msg3 can be UL grant information.

[0108] The aforementioned RAR message may also be referred to as message 2 (MSG2 or Msg2) or other names, which are not limited in this application.

[0109] For CBRA, if multiple terminal devices use the same preamble, subsequent steps are required to resolve the conflict. For example, after successfully receiving a RAR message, a terminal device can send Msg3 based on its allocated uplink resources. This Msg3 can be used to request an RRC connection and / or request conflict resolution.

[0110] For example, Msg3 may include at least one of the following: TC-RNTI indication information or the identifier of the terminal device. As an example, MSg3 may be transmitted using hybrid automatic repeat request (HARQ).

[0111] For example, the aforementioned Msg3 may also be called an RRC connection request message, a layer 2 (L2) message, a layer 3 (L3) message, or other names, which are not limited in this application.

[0112] For example, the network device can respond to Msg3 by sending message 4 (MSG4 or Msg4) to the terminal device, thereby completing the establishment of the RRC connection. For example, the aforementioned Msg4 can be called a contention resolution message, an RRC connection response message, or other names.

[0113] Based on the above four steps, the terminal device successfully connects to the network and can then perform subsequent communication and data transmission.

[0114] The above is a brief example of a four-step random access method in a 5G NR system. The initial access method in this application is not limited to the four-step random access method described above; for example, this application can also be applied to a two-step random access method or other random access methods proposed in the future.

[0115] As an example, the essence of two-step random access can be simply understood as follows: when the terminal device sends the preamble, it also sends the content used for conflict resolution contained in Msg3 of the four-step random access method to the network side. The network side can then send the content contained in Msg2 and Msg4 of the four-step random access method to the terminal device. For easier understanding, the following will combine... Figure 3 Section (b) provides an example of a two-step random access method.

[0116] See Figure 3 In (b), the terminal device can send message A (messageA, MSGA, or MsgA) to the network device.

[0117] As an example, the MsgA may include at least one of the following: RA preamble, or the identifier of the terminal device, etc.

[0118] For example, MsgA may have other names, which are not limited in this application.

[0119] See Figure 3 In (b), the network side can send message B (messageB, MSGB, or MsgB) to the terminal device.

[0120] For example, MsgB may include at least one of the following: an identifier of the preamble received by the network side, TA information, TC-RNTI, or information used for contention resolution, etc. As an example, the identifier of the preamble may be RAPID.

[0121] For example, MsgB mentioned above may have other names, which are not limited in this application.

[0122] 2. Time-domain resources of the physical random access channel (PRACH)

[0123] As an example, the time-domain resources of PRACH can be indicated by the PRACH configuration. For example, the PRACH configuration can be as shown in Table 1.

[0124] Table 1

[0125]

[0126]

[0127] Here, mod can represent modulo. f It can represent the system frame number (SFN).

[0128] For example, the PRACH configuration index (PrachConfigurationIndex) can be used to indicate the PRACH configuration, thereby indicating the PRACH temporal resources. For instance, referring to Table 1, a PRACH configuration index of 0 indicates the PRACH configuration in the first row of Table 1, thus indicating that the PRACH temporal resources begin from the 0th symbol in the subframe with subframe number 1 within the SFN corresponding to x=16 and y=1.

[0129] Table 1 above is merely an example. The PRACH configuration in this application may also include other content, for example, see Table 6.3.3.2 of 3GPP technical specification (TS) version V 18.5.0, which will not be elaborated further. In addition, the PRACH configuration may also be in the form of other tables, which are not limited in this application.

[0130] 3. TA Information

[0131] TA information (or TA value) can be used to eliminate time differences between users (or terminal devices) within a cell. For example, network devices measure the time difference based on the preamble of the terminal device during the random access procedure and calculate the TA information. Furthermore, the network device can send the calculated TA information to the terminal device via RAR. As an example, TA information can be carried in the timing advance command (TAC) field. For ease of understanding, the following will combine... Figure 4 Here's an example of a TAC field.

[0132] Figure 4 This is a schematic diagram of the contents of a RAR file. See also... Figure 4 , Figure 4 The eight fence-like symbols at the top represent eight bits, each bit being associated with... Figure 4 Field alignment in the code. For example, Figure 4 The length or size of the R field in the code is 1 bi.

[0133] In this context, field R can represent a reserved field. The TAC field can be 12 bits long or of other lengths. The UL authorization field can be 25 bits long or of other lengths. The TC-RNTI field can be 16 bits long or of other lengths.

[0134] Among them, the above Figure 4 This application is for illustrative purposes only and does not limit the specific fields that the RAR can contain or the length of each field. A RAR can contain... Figure 4 The fields shown can also include other fields. Fields included in a RAR file can be such as... Figure 4 The length shown can also be other lengths.

[0135] After the terminal device receives the RAR, it can calculate the TA based on the TA information in the RAR, adjust the transmission time according to the TA, and thus complete UL time synchronization (or UL timing synchronization).

[0136] As an example, TA can be calculated using the following formula:

[0137] TA = N TA *T c

[0138] Where, N TA It can represent TA information. T c This can be the smallest granularity that TA can adjust. T cThe specific values ​​can be configured according to the predefined methods of the protocol, for example, refer to 3GPPTS 38.211V18.5.0, which will not be elaborated here. As an example, when the subcarrier spacing (SCS) is 15 kHz, T c =0.52.

[0139] 4. NTN system

[0140] Compared to traditional mobile communication systems, NTN systems offer wider coverage. For example, NTN systems can overcome natural geographical barriers such as oceans, deserts, or mountains to enable communication.

[0141] For example, based on different orbital altitudes, NTN systems can be divided into the following three types: geostationary earth orbit (GEO) satellite communication systems, also known as geostationary orbit satellite systems; medium earth orbit (MEO) satellite communication systems; and low earth orbit (LEO) satellite communication systems.

[0142] GEO satellite communication systems can include GEO satellites. GEO satellites are also known as geostationary orbit satellites. The orbital altitude of a GEO satellite can be approximately 35,786 kilometers (km). GEO satellites can be stationary relative to the ground and have a large signal coverage area.

[0143] The MEO satellite communication system can include MEO satellites. MEO satellites can orbit at altitudes ranging from approximately 2000 to 35786 km. Global coverage can be achieved with a relatively small number of MEO satellites. MEO satellites can be used for positioning and navigation.

[0144] The LEO satellite communication system can include LEO satellites. LEO satellites can orbit at altitudes ranging from approximately 300 to 2000 km. Compared to GEO and MEO satellites, LEO satellites have lower orbital altitudes, lower data transmission latency, lower power loss, and lower launch costs.

[0145] However, the transmission latency of NTN systems is much greater than that of traditional communication systems (e.g., ground-based communication systems). Therefore, NTN systems need to be redesigned in terms of timing, for example, by redesigning how terminal devices obtain TA (or the "TA mechanism").

[0146] 5. TA mechanism in NTN system

[0147] In some schemes (denoted as Scheme A), the terminal equipment has the capability to support the Global Navigation Satellite System (GNSS). In this way, the terminal equipment can determine its Time Accomplishment (TA) based on GNSS, thereby achieving UL time synchronization.

[0148] However, in Scheme A above, the terminal device needs to rely on GNSS to achieve UL time synchronization, which increases the cost and power consumption of the terminal device. Furthermore, some terminal devices do not support GNSS, and these terminal devices cannot achieve UL time synchronization using Scheme A.

[0149] Since the terminal device's transmission time domain unit may not be within the network device's reception time domain unit (i.e., the network device's preamble detection time window), the network device may be unable to detect the preamble transmitted by the terminal device. In other schemes (denoted as Scheme B), the terminal device can achieve UL time synchronization by adjusting the preamble transmission time multiple times based on a certain adjustment step size. As an example, under a certain adjustment step size, the number of adjustments by the terminal device can satisfy the following relationship:

[0150] Number of adjustments = (Sampling rate * RTT) / Adjustment step size

[0151] In the formula above, "*" represents multiplication, and " / " represents division. For ease of understanding, the following example illustrates the scheme.

[0152] For example, assuming the satellite base station is 750 kilometers (km) away from the terminal, the RRT can be obtained as follows: Here, 300 kilometers per millisecond (km / ms) can represent the speed of light. If the terminal device uses a Fast Fourier Transform (FFT) step size of 2048 points, the number of adjustments required to complete UL time synchronization at different sampling rates is shown below.

[0153] • Sampling rate 30.72MHz, adjustment times 75.

[0154] • Sampling rate 61.44MHz, adjustment times 150.

[0155] ● Sampling rate 122.88MHz, adjustment times 300.

[0156] ● Sampling rate 245.76MHz, adjustment times 600.

[0157] • Sampling rate 491.52MHz, adjustment times 1200.

[0158] As can be seen, if the terminal device implements UL time synchronization based on the above scheme B, it requires many adjustments, which results in a very long UL time synchronization time. In other words, the efficiency of UL time synchronization is very low. Furthermore, UL time synchronization is a crucial step in random access, and the above scheme B increases the overall time for the terminal device to perform random access, reducing the efficiency of random access.

[0159] In view of this, this application proposes a communication method. This method can improve the efficiency of time synchronization between network devices and terminal devices, thereby helping to improve the random access efficiency of terminal devices. The following describes a method in conjunction with... Figure 5 Here are specific examples of the methods described above.

[0160] Figure 5 This is a schematic flowchart of a communication method 500 provided in an embodiment of this application. Optional operations in method 500 are shown with dashed lines. The nodes involved in method 500 are described below.

[0161] First communication device. Unless otherwise specified, the first communication device in this application can be a network device, a component applicable to a network device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing some or all of the functions of a network device. For ease of description, the following description will take a network device as the first communication device.

[0162] Second communication device. Unless otherwise specified, the second communication device in this application can be a terminal device, a component applicable to a terminal device (e.g., a processor, chip, or chip system), or a logic module or software capable of implementing some or all of the functions of the terminal device. For ease of description, the following description assumes that the second communication device is a terminal device.

[0163] Method 500 is described using the interaction between a network device and a terminal device as an example. In some examples, Method 500 may involve more nodes, and this application does not limit this. The following section combines... Figure 5 This section introduces the various operations of method 500.

[0164] In S510, the network device detects the preamble based on the first pattern. Correspondingly, the terminal device sends the preamble based on the second pattern. An example of the network device detecting the preamble is described below.

[0165] For example, the first pattern can be used to indicate preamble detection on R time-domain units out of P time-domain units, where P is a positive integer and R is a positive integer less than or equal to P. It is understood that the R time-domain units can be some or all of the P time-domain units.

[0166] In some possible implementations, S510 includes: the network device performing preamble detection on R time-domain units out of P time-domain units based on a first pattern.

[0167] As an example, a time-domain unit can be a symbol, time slot, subframe, frame, millisecond, second, or other time-domain resource unit.

[0168] In some examples, the first pattern may be predefined by the protocol, pre-configured in the network device, determined by the network device, or obtained by the network device in other ways.

[0169] As an example, the first pattern may be called a first bitmap, detection bitmap, detection pattern, first mode, detection mode, first type, detection type, or other names. This application does not limit the name of the first pattern. In some examples, the first pattern may include P bits, each of which corresponds one-to-one with a P time-domain unit. As an example, the P bits include R bits with a value of 1. The time-domain units corresponding to the bits with a value of 1 among the P bits belong to the R time-domain units, while the time-domain units corresponding to the bits with a value of 0 do not belong to the R time-domain units. For example, the first pattern is 1110000000000000 (i.e., P = 15, R = 3), and the 15 bits in the first pattern correspond one-to-one with time-domain units #1 to #15. The first pattern in the above example can indicate that time-domain units #1 to #3 belong to the R time-domain units; that is, the network device can perform preamble detection on time-domain units #1 to #3 based on the first pattern. The first pattern in the example above can indicate that time domain units #4 to #15 do not belong to R time domain units. That is, the network device can perform no preamble detection on time domain units #4 to #15 based on the first pattern.

[0170] As another example, P bits contain R bits with a value of 0. The time-domain units corresponding to the bits with a value of 0 belong to all R time-domain units, while the time-domain units corresponding to the bits with a value of 1 do not belong to any of the R time-domain units. Further examples will not be provided.

[0171] In other examples, the first pattern may include P bits, some of which correspond to P time-domain units, while the remaining bits are meaningless. For example, in the first pattern, each of the P / 2 bits corresponds to two time-domain units out of the P time-domain units, and the remaining P / 2 bits are meaningless. As an example, the aforementioned P / 2 bits may contain R / 2 bits with a value of 1, and the two time-domain units corresponding to each of the R / 2 bits with a value of 1 belong to the R time-domain units. As another example, the aforementioned P / 2 bits may contain R / 2 bits with a value of 0, and the two time-domain units corresponding to each of the R / 2 bits with a value of 0 belong to the R time-domain units.

[0172] In some examples, the number of bits in the first pattern may be greater than P or less than P. There is a correspondence between the bits in the first pattern and the P time-domain units. This correspondence ensures that each of the P time-domain units corresponds to a specific bit in the first pattern. One bit in the first pattern may correspond to one or more time-domain units among the P time-domain units; specific examples will not be elaborated further.

[0173] As an example, in S510, the network device performs preamble detection on R time-domain units based on a first pattern, and can obtain one or more preambles. These one or more preambles can be referred to as the first preamble. In other words, the first preamble can be one or more preambles obtained by the network device based on the first pattern.

[0174] As an example, a network device may detect a preamble on some time-domain cells out of R time-domain cells, but not on others. The preambles detected by the network device can be collectively referred to as the first preamble. As another example, a network device may detect a preamble on all time-domain cells out of R time-domain cells; these preambles can also be collectively referred to as the first preamble.

[0175] The following is an example of a terminal device sending a preamble.

[0176] For example, the second pattern can be used to indicate the transmission of S preambles in S time-domain units out of P time-domain units, where S is a positive integer less than or equal to P. It is understood that the S time-domain units can be some or all of the P time-domain units.

[0177] In some possible implementations, S510 includes: the terminal device transmitting S preambles in S time-domain units out of P time-domain units based on the second pattern. For example, the terminal device transmits preamble #1 in time-domain unit #1; the terminal device transmits preamble #2 in time-domain unit #2; and so on, transmitting preamble #S in time-domain unit #S. The preambles #1 to #S mentioned above may be the same or different, and this application does not limit this.

[0178] As an example, the terminal device can periodically send a preamble based on the second pattern. For instance, after executing S510 once, the terminal device can execute S510 again.

[0179] For example, when a terminal device sends a preamble, it can be understood as the terminal device sending a PRACH.

[0180] In some examples, the second pattern may be predefined by the protocol, pre-configured in the terminal device, configured by the network device, or obtained by the terminal device through other means.

[0181] As an example, the second pattern may be referred to as a second bitmap, a transmit bitmap, a transmit pattern, a second mode, a transmit mode, a second type, a transmit type, or other names. This application does not limit the name of the second pattern.

[0182] In some examples, the second pattern may include P bits, each corresponding one-to-one with one of the P time-domain units. As an example, the P bits may include S bits with a value of 1. The time-domain units corresponding to the bits with a value of 1 belong to the S time-domain units, while the time-domain units corresponding to the bits with a value of 0 do not belong to the S time-domain units. For example, the second pattern might be 100100100100100 (i.e., P = 15, S = 5), where the 15 bits correspond one-to-one with time-domain units #1 to #15. The second pattern in the above example can indicate that time-domain units #1, #4, #7, #10, and #13 belong to the S time-domain units; that is, the terminal device can send a preamble on these time-domain units based on the second pattern. The second pattern in the example above can indicate that time domain unit #2, time domain unit #3, time domain unit #5, time domain unit #6, time domain unit #8, time domain unit #9, time domain unit #11, time domain unit #12, time domain unit #14 and time domain unit #15 do not belong to S time domain units. That is, the terminal device can, based on the second pattern, not send a preamble on the above time domain units.

[0183] As another example, P bits contain S bits with a value of 0. The time-domain units corresponding to the bits with a value of 0 belong to all S time-domain units, while the time-domain units corresponding to the bits with a value of 1 do not belong to any of the S time-domain units. Further examples will not be provided.

[0184] In other examples, the second pattern may include P bits, some of which correspond to P time-domain units, while the remaining bits are meaningless. For example, in the second pattern, each of the P / 2 bits corresponds to two time-domain units out of the P time-domain units, and the remaining P / 2 bits are meaningless. As an example, the above P / 2 bits may contain S / 2 bits with a value of 1, and the two time-domain units corresponding to each of the S / 2 bits with a value of 1 belong to the S time-domain units. As another example, the above P / 2 bits may contain S / 2 bits with a value of 0, and the two time-domain units corresponding to each of the S / 2 bits with a value of 0 belong to the S time-domain units. Specific examples will not be elaborated further.

[0185] In some examples, the number of bits in the second pattern may be greater than P or less than P. There is a correspondence between the bits in the second pattern and the P time-domain units. This correspondence ensures that each of the P time-domain units corresponds to a specific bit in the second pattern. One bit in the second pattern may correspond to one or more time-domain units among the P time-domain units; specific examples will not be elaborated further.

[0186] The number of bits in the second pattern may be the same as or different from the number of bits in the first pattern; this application does not impose any restrictions.

[0187] As an example, the terminal device sending a preamble based on the second pattern may include: the terminal device sending S preambles in S time-domain units out of P time-domain units, based on the second pattern. The first preamble detected by the network device may include some or all of the aforementioned S preambles.

[0188] For example, after the S time-domain units have cyclically moved any number of time-domain units over the P time-domain units, there is at least one time-domain unit overlapping between the S time-domain units and the R time-domain units.

[0189] For example, assuming S=5 and P=15: Time domain units #1, #4, #7, #10, and #13 are shifted one time domain unit to the right in a cyclic manner over 15 time domain units to obtain time domain units #2, #5, #8, #11, and #14; Time domain units #1, #4, #7, #10, and #13 are shifted two time domain units to the right in a cyclic manner over 15 time domain units to obtain time domain units #3, #6, #9, #12, and #15.

[0190] At least one time-domain unit overlaps between S time-domain units and R time-domain units. This can be understood as at least one time-domain unit in the S time-domain units sharing the same position in the P time-domain units as at least one time-domain unit in the R time-domain units. For example, one time-domain unit in the S time-domain units is the first time-domain unit in the P time-domain units, and one time-domain unit in the R time-domain units is also the first time-domain unit in the P time-domain units. Thus, there is one time-domain unit overlap between the S time-domain units and the R time-domain units, and this overlapping time-domain unit is the first time-domain unit in the P time-domain units.

[0191] To facilitate understanding, the following example uses the first pattern mentioned above, which includes 15 bits and corresponds one-to-one with the 15 time-domain units, and the second pattern, which also includes 15 bits and corresponds one-to-one with the 15 time-domain units, to illustrate how S time-domain units are cyclically moved across P time-domain units, and how at least one time-domain unit overlaps between the S time-domain units and R time-domain units after the cyclic movement.

[0192] In the previous example, the first pattern could be 111000000000000, and the second pattern could be 100100100100100. The R time-domain units can be understood as the time-domain units corresponding to the bits with a value of 1 in the first pattern, and the S time-domain units can be understood as the time-domain units corresponding to the bits with a value of 1 in the second pattern.

[0193] Thus, the S time-domain units cyclically move across P time-domain units, which can be understood as the second pattern "100100100100100" cyclically moving. This cyclic movement of the S time-domain units can be either left-handed or right-handed; this application does not limit this. The derivation process of the N*K third patterns is described below using the example of the S time-domain units cyclically moving right across P time-domain units.

[0194] For example, shifting time-domain units #1, #4, #7, #10, and #13 one time-domain unit to the right in a cyclic shift of P time-domain units yields time-domain units #2, #5, #8, #11, and #14. Shifting the second pattern "100100100100100" one bit to the right in a cyclic shift yields "010010010010010". It is evident that the positions of the bits with a value of 1 in "010010010010010" still correspond to the positions of time-domain units #2, #5, #8, #11, and #14 within the 15 time-domain units. For example, shifting time-domain units #1, #4, #7, #10, and #13 two time-domain units to the right across P time-domain units yields time-domain units #3, #6, #9, #12, and #15. Shifting the second pattern "100100100100100" two bits to the right yields "001001001001001". It is evident that the positions of the bits with a value of 1 in "001001001001001" still correspond to the positions of time-domain units #3, #6, #9, #12, and #15 within the 15 time-domain units.

[0195] It is understandable that moving to the left and moving to the right in a circular motion are equivalent in result, so examples of moving to the left in a circular motion will not be repeated.

[0196] Furthermore, it is understandable that when the second pattern "100100100100100" is cyclically shifted any number of bits, there exists a bit with a value of "1" in the second pattern after the shift, and its position is the same as that of a bit with a value of "1" in the first pattern "111000000000000". In other words, when the second pattern "100100100100100" is cyclically shifted any number of bits, there exists a bit with a value of 1 at a certain position in the second pattern, and the bit with a value of 1 at that position in the first pattern is also 1. For example, Table 2 shows the correspondence between the second pattern "100100100100100" and the first pattern after cyclically shifting any number of bits.

[0197] Table 2

[0198] First pattern Second pattern 111000000000000 100100100100100 111000000000000 010010010010010 111000000000000 001001001001001

[0199] In Table 2, bits in the first and second patterns that are in the same position and have a value of 1 are shown in bold. For example, referring to the first row of Table 2, the first bit of the first pattern has a value of 1, and the first bit of the second pattern has a value of 1. Referring to the second row of Table 2, the second bit of the first pattern has a value of 1, and the second bit of the second pattern has a value of 1. Referring to the third row of Table 2, the third bit of the first pattern has a value of 1, and the third bit of the second pattern has a value of 1.

[0200] The above examples illustrate the cyclic movement of S time-domain units across P time-domain units by using the cyclic movement of the second pattern, and demonstrate that at least one bit with a value of 1 in the second pattern after the cyclic movement is the same as the position of a bit with a value of 1 in the first pattern, thus indicating that at least one time-domain unit overlaps between the S time-domain units and the R time-domain units. These examples are merely for ease of understanding; the essence of the embodiments of this application lies in the cyclic movement of the S time-domain units and the overlap between the S time-domain units and the R time-domain units after the cyclic movement. Therefore, even if no bit with a value of 1 in the second pattern after the cyclic movement is the same as the position of a bit with a value of 1 in the first pattern, as long as at least one time-domain unit in the S time-domain units indicated by the second pattern overlaps with at least one time-domain unit in the R time-domain units indicated by the first pattern after the cyclic movement, it still falls within the scope of the embodiments of this application.

[0201] As mentioned earlier, after the S time-domain units are cyclically moved any number of time-domain units over the P time-domain units, at least one time-domain unit overlaps with the R time-domain units. In other words, regardless of the offset between the terminal device's transmitting time-domain unit and the network device's receiving time-domain unit, at least a portion of the S preambles transmitted by the terminal device over the S time-domain units will fall into the R time-domain units; that is, at least a portion of the preambles can be detected by the network device based on the first pattern.

[0202] In step S520, the network device sends first information to the terminal device based on a first preamble. This first information can be used for time synchronization between the network device and the terminal device. Correspondingly, the terminal device receives the first information from the network device.

[0203] As an example, the first piece of information may include TA information. Examples of TA information can be found in Item 3 of the terminology explanation section above, and will not be repeated here.

[0204] In some possible implementations, S520 may include: the network device determining first information based on the first preamble; and the network device sending the first information to the terminal device. For example, the network device may detect the first preamble, obtain the detection peak value of the first preamble, and determine the TA information corresponding to the detection peak value. Further, the network device may carry the TA information in the first information and send the first information to the terminal device.

[0205] As an example, the first message can be carried in a RAR. The RAR could be Msg2 in a four-step random access method or MsgB in a two-step random access method. As another example, the first message can be carried in other messages besides RAR; for example, it could be carried in a message of a future proposed random access method. Yet another example is that the first message could be carried in a future message used for time synchronization. And yet another example is that the first message could be carried in a DCI (Distributed Access Message).

[0206] In some possible implementations, method 500 also includes: S530.

[0207] S530: Based on the first information, the terminal device performs time synchronization between itself and the network device. For example, UL time synchronization.

[0208] For example, the first information may include TA information. The terminal device can align its transmit time domain unit with the network device's receive time domain unit based on this TA information, thereby achieving time synchronization at the time domain unit level. Exemplarily, the aforementioned time domain unit may be a symbol.

[0209] In some examples, method 500 can be applied to scenarios involving multiple terminal devices. Multiple terminal devices can send different preambles to the same network device. Thus, the network device can distinguish between multiple terminal devices based on the detected preambles. Multiple terminal devices can use the same or different second patterns; this application does not limit this. For example, terminal device #1 sends preamble #1 to the network device using second pattern #1, and terminal device #2 sends preamble #2 to the network device using second pattern #2. Preamble #1 and preamble #2 can be different. Second pattern #1 and second pattern #2 can be the same or different.

[0210] Based on the above scheme, by designing the first and second patterns, it is ensured that after the S time-domain units are cyclically moved any number of time-domain units across the P time-domain units, at least one time-domain unit still belongs to the R time-domain units. Thus, regardless of the time-domain unit offset between the terminal device's transmitting time-domain unit and the network device's receiving time-domain unit, at least a portion of the preamble transmitted by the terminal device using the second pattern will always be detectable by the network device. Therefore, the above scheme avoids the situation where the preamble transmitted by the terminal device cannot be detected by the network device. Furthermore, the network device can send first information for time synchronization based on the detected first preamble, thereby achieving time synchronization. It is evident that this scheme can ensure that the network device detects the preamble, thereby improving the efficiency of time synchronization between the network device and the terminal device.

[0211] Furthermore, the terminal device in method 500 may or may not have GNSS support capabilities. Therefore, compared to scheme A mentioned earlier, which requires the terminal device to have GNSS support capabilities, method 500 is applicable to terminal devices with various capabilities, making it more versatile. On the other hand, method 500 does not rely on GNSS and can achieve UL time synchronization. Therefore, compared to scheme A mentioned earlier, which requires the terminal device to achieve UL time synchronization based on GNSS, method 500 reduces the power consumption of the terminal device.

[0212] Furthermore, since the terminal device's transmission time domain unit may not be within the network device's reception time domain unit (i.e., the network device's time window for detecting the preamble), the network device may be unable to detect the preamble transmitted by the terminal device. Therefore, in Scheme B mentioned above, the terminal device, based on a certain adjustment step size, adjusts the transmission time of the preamble multiple times to ultimately achieve UL time synchronization. In Method 500, by designing the first and second patterns, after the S time domain units indicated by the second pattern are cyclically moved any number of time domain units over P time domain units, at least one time domain unit overlaps with the R time domain units indicated by the first pattern. Thus, regardless of how many time domain units are offset between the terminal device's transmission time domain unit and the network device's reception time domain unit, at least a portion of the preamble transmitted by the terminal device using the second pattern can always be detected by the network device. In other words, by transmitting the preamble based on the second pattern, the terminal device can ensure that the network device can detect the preamble based on the first pattern. Therefore, compared to Solution B, which requires multiple adjustments to complete UL time synchronization, Method 500 can achieve time synchronization at the time domain unit level with a single adjustment, thereby reducing the time required for UL time synchronization. This helps to reduce the overall time for terminal devices to perform random access and improve random access efficiency.

[0213] The above, in conjunction with S510, S520, and S530, describes an example of time synchronization at the time-domain unit level between a terminal device and a network device. For example, time synchronization at the time-domain unit level can be understood as time-domain unit header alignment (e.g., symbol header alignment), or in other words, alignment of the starting positions of the time-domain units.

[0214] The following section presents an example of time synchronization at the pattern period level. In this example, the network device can determine whether the terminal device and the network device have completed radio frame-level time synchronization by detecting a check sequence, and quickly determine the number of pattern periods offset between the network device's pattern period and the terminal device's pattern period on the radio frame. This facilitates rapid radio frame-level time synchronization between the terminal device and the network device. For ease of understanding, examples related to pattern periods and time-domain unit groups are introduced first.

[0215] As an example, P time-domain units can be considered as one pattern period. For instance, the length of a pattern period can be the length of P time-domain units. This application does not limit the specific name of the pattern period; for example, the pattern period can be called a PRACH transmission sub-cycle or other names. For ease of description, the name "pattern period" will be used below.

[0216] In some examples, the aforementioned P time-domain units can be N*K time-domain units in a group of N time-domain units. In other words, P = N*K. For example, each of the N time-domain unit groups includes K time-domain units.

[0217] As an example, a pattern period can include N time-domain cell groups. For instance, the length of a pattern period can be the length of N time-domain cell groups.

[0218] For example, in the previous example, the first pattern could be 111000000000000, the second pattern could be 100100100100100, and P = 15 time-domain elements could be 3 * 5 time-domain elements in 3 time-domain element groups, that is, N = 3 and K = 5. As another example, N = 5, K = 15, that is, P = 75 time-domain elements could be 5 * 15 time-domain elements in 5 time-domain element groups. Each time-domain element group includes 15 time-domain elements.

[0219] As an example, a time-domain cell group can be called a time-domain cell set or other names.

[0220] For example, a time-domain unit can be a symbol, and a time-domain unit group can be a time slot, subframe, frame, millisecond, second, or other time-domain resource unit.

[0221] For example, a time-domain unit can be a time slot, and a time-domain unit group can be a subframe, frame, millisecond, second, or other time-domain resource unit.

[0222] For example, a temporal unit can be a subframe, and a group of temporal units can be a frame, millisecond, second, or other temporal resource unit. Other examples will not be elaborated further.

[0223] In some possible implementations, method 500 further includes: S535, the network device determines a first offset based on the time-domain cell group to which the time-domain cell of the detected first preamble belongs and N*K third patterns.

[0224] As an example, the time-domain units in which the first preamble is detected can be some or all of the aforementioned R time-domain units. In other words, the network device may detect the preamble in some of the R time-domain units, thus the first preamble consists of fewer than R preambles. Alternatively, the network device may detect the preamble in all of the R time-domain units, thus the first preamble consists of R preambles.

[0225] As an example, the third pattern can be used to indicate the number of preambles detected in each of the N time-domain cell groups. Alternatively, the third pattern can be used to indicate the number of time-domain cells in each of the N time-domain cell groups where a preamble was detected.

[0226] In some examples, the third pattern may include N values. Each of the N values ​​corresponds one-to-one with one of the N time-domain cell groups. Each of the N values ​​indicates the number of preambles detected by the network device in each of the N time-domain cell groups. For example, assuming N = 5, a third pattern of 00003 could indicate that the network device did not detect a preamble in the first four time-domain cell groups, but detected three preambles in the fifth time-domain cell group. Alternatively, it could mean that the network device detected a preamble in each of the three time-domain cells within the fifth time-domain cell group.

[0227] In other examples, the third pattern indicates the number of preambles detected in each of the N time-domain cell groups, or the number of time-domain cells in each of the N time-domain cell groups that detected the preamble, which can be done in other ways.

[0228] For example, the third pattern may be referred to as a third bitmap, decision bitmap, decision pattern, third mode, decision mode, third type, decision type or other names, and this application does not limit the name of the third pattern.

[0229] As an example, N*K third patterns can be obtained by sequentially shifting the S time-domain units indicated by the second pattern by 1 to N*K time-domain units over P time-domain units. This cyclic shift of P time-domain units (or N*K time-domain units) can be a leftward or rightward shift; this application does not limit this. The derivation process of N*K third patterns is described below using the example of S time-domain units cyclically shifting rightward over P time-domain units.

[0230] For example, after S time-domain units are cyclically shifted one time-domain unit to the right over P time-domain units, the overlapping time-domain units between the R time-domain units indicated by the first pattern and the S time-domain units after the cyclic shift can be determined. By counting the time-domain unit groups to which the overlapping time-domain units belong, the number of preambles that the network device can detect in each of the N time-domain unit groups can be obtained (or, the number of time-domain units that detect preambles in each of the N time-domain unit groups), that is, the third pattern #1 is obtained.

[0231] Based on the previous example, the second pattern could be 100100100100100. Thus, shifting one time-domain unit to the right, the second pattern could be 010010010010010. Assuming P = 15 time-domain units can be 3 * 5 time-domain units in 3 time-domain unit groups, i.e., N = 3, K = 5. Thus, the network device can perform detection based on the first pattern (which could be 111000000000000), resulting in the third pattern #1 being "200". "200" indicates that two preambles were detected in the first time-domain unit group (or, two time-domain units in the first time-domain unit group detected the preamble), while no preambles were detected in other time-domain unit groups (or, no time-domain units in other time-domain unit groups detected the preamble). For example, after S time-domain cells are cyclically moved two time-domain cells to the right from P time-domain cells, the overlapping time-domain cells between the R time-domain cells indicated in the first pattern and the S time-domain cells after the cyclic movement can be determined. By counting the time-domain cell groups to which the overlapping time-domain cells belong, the third pattern #2 can be obtained.

[0232] Based on the previous example, the second pattern could be 100100100100100. Then, shifting two time-domain units to the right, the second pattern could be 001001001001001. Assuming P = 15 time-domain units can be 3 * 5 time-domain units in 3 time-domain unit groups, i.e., N = 3, K = 5. Thus, the network device can perform detection based on the first pattern, which could be 111000000000000, and the resulting third pattern #2 could be "100". "100" indicates that one preamble was detected in the first time-domain unit group (or, one time-domain unit in the first time-domain unit group detected the preamble), and no preamble was detected in other time-domain unit groups (or, no time-domain unit in other time-domain unit groups detected the preamble).

[0233] For example, following this logic, after the S time-domain cells are cyclically shifted N*K time-domain cells to the right over the P time-domain cells, the overlapping time-domain cells between the R time-domain cells indicated in the first pattern and the S time-domain cells after the cyclic shift can be determined. By counting the time-domain cell groups to which these overlapping time-domain cells belong, the third pattern #N*K can be obtained.

[0234] Based on the previous example, the second pattern could be 100100100100100. Thus, after shifting 3 time-domain units to the right, the second pattern could be 100100100100100. Assuming P = 15 time-domain units can be 3 * 5 time-domain units in 3 time-domain unit groups, i.e., N = 3, K = 5. Thus, the network device, based on the first pattern (which could be 111000000000000), performs detection, and the resulting third pattern #3 (i.e., third pattern #N * K) can be "100". "100" indicates that one preamble was detected in the first time-domain unit group (or, one time-domain unit in the first time-domain unit group detected the preamble), and no preamble was detected in other time-domain unit groups (or, no time-domain unit in other time-domain unit groups detected the preamble).

[0235] In this case, the S time-domain units are cyclically moved N*K time-domain units to the right over the P time-domain units. This can also be understood as the S time-domain units not being cyclically moved.

[0236] It is understandable that moving to the left and moving to the right in a circular motion are equivalent in result, so examples of moving to the left in a circular motion will not be repeated.

[0237] Furthermore, it is understandable that, as mentioned earlier, after the S time-domain units cyclically move any number of time-domain units over the P time-domain units, there is at least one time-domain unit overlap with the R time-domain units. Therefore, the number of preambles detected in each of the N time-domain unit groups is not all zero. In other words, the number of time-domain units in each time-domain unit group that detect the preamble is not all zero. In other words, the N values ​​corresponding to the N time-domain unit groups indicated by any one of the N*K third patterns are not all zero. For example, assuming N=5 and K=15, the N*K third patterns may contain a pattern of "00003" (i.e., the 5th value among the N values ​​is 3), but the N*K third patterns do not contain "00000". The reason is that "00000" means that none of the 5 time domain units include time domain units that can be detected by the network device, which contradicts the statement that "after the S time domain units move cyclically over the P time domain units, there is at least one time domain unit that overlaps with the R time domain units".

[0238] In some examples, two of the N*K third patterns are identical. For instance, referring to the previous example, the first pattern could be 111000000000000, and the second pattern could be 100100100100100. Third pattern #1 is "200", third pattern #2 is "100", and third pattern #3 is "100". Third pattern #2 and third pattern #3 are identical.

[0239] In other examples, any two of the N*K third patterns are different. For instance, each of the N*K third patterns may include N numerical values. The statement that any two of the N*K third patterns are different can be understood as any two of the N*K third patterns including different numerical values; for example, one third pattern includes 00003 and the other includes 00004. Alternatively, it can be understood as the same numerical values ​​being in different positions within the N*K third patterns; for example, one third pattern includes 00003 and the other includes 00030.

[0240] Since any two of the N*K third patterns are different, the number of time-domain units that cyclically move across the P time-domain units from the S time-domain units can uniquely correspond to one of the N*K third patterns. For example, there are N*K possible ways to cyclically move across the P time-domain units from the S time-domain units, and these N*K ways can be matched one-to-one with the N*K third patterns.

[0241] Furthermore, the number of time-domain units that cyclically move across P time-domain units can also be understood as the number of time-domain units offset between the receiving time-domain unit of the network device and the transmitting time-domain unit of the terminal device. Therefore, based on one of the N*K third patterns, it is possible to uniquely determine which of the N*K cases the number of time-domain units offset between the receiving time-domain unit of the network device and the transmitting time-domain unit of the terminal device represents.

[0242] For ease of understanding and description, the number of time domain units offset between the receiving time domain unit of the network device and the transmitting time domain unit of the terminal device will be referred to as "time domain unit offset".

[0243] In the above example, the N*K third patterns can correspond one-to-one with N*K types of time-domain unit offsets. For example, the N*K types of time-domain unit offsets indicate offsets of 1, 2, ..., N*K time-domain units between the receiving time-domain unit of the network device and the transmitting time-domain unit of the terminal device; or, the N*K time-domain unit offsets indicate offsets of 0 (i.e., no time-domain unit offset), 1, ..., N*K-1 time-domain units between the receiving time-domain unit of the network device and the transmitting time-domain unit of the terminal device.

[0244] In some possible implementations, S535 includes: the network device determining the number of preambles detected in each of the N time-domain unit groups based on the time-domain unit group to which the time-domain unit to which the first preamble belongs, or determining the number of time-domain units in each time-domain unit group to which the preamble is detected, thereby determining the third pattern corresponding to the first preamble; the network device determining the first offset based on the correspondence between the N*K time-domain unit offsets and the N*K third patterns, and the third pattern corresponding to the first preamble.

[0245] For example, the first offset can be used to indicate the time-domain unit offset corresponding to the "third pattern corresponding to the first preamble" in the correspondence between N*K time-domain unit offsets and N*K third patterns. As another example, the first offset can be used to indicate the number of time-domain units offset between the receiving time-domain unit of the network device and the time-domain unit of the terminal device (i.e., the terminal device that sends the first preamble).

[0246] For example, the first offset may be called time-domain cell offset, PRACH time-domain cell advance, PRACH advance, or other names. This application does not limit the specific name of the first offset.

[0247] As an example, assuming N=5, the network device does not detect the preamble in the first 4 time-domain unit groups, but detects 3 preambles in the 5th time-domain unit group (or, the preamble is detected in 3 time-domain units in the 5th time-domain unit group). In this way, the network device can determine that the third pattern corresponding to the first preamble is "00003".

[0248] Furthermore, the network device can determine the time-domain cell offset corresponding to the third pattern "00003" based on the mapping relationship between the N*K third patterns and the N*K time-domain cell offsets. This time-domain cell offset can be the first offset mentioned in S535 above.

[0249] In some examples, the mapping between N*K third patterns and N*K time-domain cell offsets can be predefined by the protocol, pre-configured in the network device, determined by the network device, or obtained by the network device in other ways.

[0250] Based on the above scheme, the network device can determine the number of preambles detected in each of the N time-domain unit groups based on the time-domain unit group to which the detected first preamble belongs, thereby obtaining the third pattern corresponding to the first preamble. Any two of the N*K third patterns are different, and each of the N*K third patterns corresponds one-to-one with N*K time-domain unit offsets between the network device's receiving time-domain unit and the terminal device's transmitting time-domain unit across P time-domain units. Therefore, the network device can uniquely determine the number of time-domain units offset between the network device's receiving time-domain unit and the terminal device's transmitting time-domain unit, i.e., the first offset, based on the third pattern corresponding to the first preamble and the aforementioned correspondence. The above scheme designs the first and second patterns to ensure that any two of the N*K third patterns are different. In this way, the network device can determine the number of time domain units offset between the receiving time domain unit of the network device and the transmitting time domain unit of the terminal device in one step based on the time domain unit group to which the time domain unit of the detected first preamble belongs, and N*K third patterns, thereby helping to quickly achieve pattern period-level time synchronization between the network device and the terminal device.

[0251] In some possible implementations, method 500 also includes: S540 and S545.

[0252] S540, the network device sends an indication of the first offset to the terminal device. Correspondingly, the terminal device receives the indication of the first offset from the network device.

[0253] In some examples, the indication information of the first offset mentioned above can be carried in the first information, or in other words, the first information can include the indication information of the first offset. In this way, S540 and S520 can be regarded as a single operation.

[0254] As an example, after executing S510 and S535, the network device may send first information to the terminal device, which may include indication information of a first offset.

[0255] In other examples, the indication information for the first offset mentioned above can be carried in other information besides the first information. In this way, S540 and S520 can be regarded as two operations.

[0256] As an example, after executing S510, the network device can execute S520, which sends the first information to the terminal device. Further, the network device can execute S535, which determines the first offset; and further still, the network device can execute S540, which sends an indication of the first offset to the terminal device.

[0257] As another example, a network device can execute S540 and S520 simultaneously. For instance, the network device can send first information and indication information of a first offset to a terminal device.

[0258] S545, the terminal device sends a second preamble to the network device based on the first offset and the second pattern. Correspondingly, the network device receives the preamble based on the first pattern.

[0259] For example, based on the first offset, the terminal device can align its pattern period with that of the network device. Based on the second pattern, the terminal device can send S preambles (denoted as the second preamble in S545) in S time-domain units within the aligned pattern period.

[0260] As an example, the second preamble can be one or more preambles sent by the terminal device based on the first offset and the second pattern in S545. Correspondingly, the network device can receive part or all of the preambles in the second preamble based on the first pattern.

[0261] As an example, S545 is executed after S510. Thus, the time-domain positions of the S time-domain units used to send the second preamble in S545 are located after the S time-domain units corresponding to the S preambles (including the first preamble) sent by the terminal device in S510.

[0262] The above, in conjunction with S535, S540, and S545, illustrates an example of pattern-period level time synchronization between a terminal device and a network device. For example, pattern-period level time synchronization can be understood as the alignment of the starting positions of P time-domain units, or the alignment of the starting positions of N time-domain unit groups.

[0263] The following is an example of time synchronization at the wireless frame level.

[0264] As an example, a radio frame can be used to represent a PRACH transmission period. For instance, a radio frame can be a time-domain unit representing a PRACH transmission period in the current NR protocol. It is understood that the radio frame in this application can be replaced by a time-domain unit representing a PRACH transmission period in future communication protocols; the radio frame in this application is merely an example for ease of understanding.

[0265] In some possible implementations, method 500 also includes S550.

[0266] In S550, the terminal device transmits a verification sequence in the time domain units excluding the S time domain units out of the P time domain units. Correspondingly, the network device receives the verification sequence.

[0267] As an example, the check sequence can be different from the S preambles sent by the terminal device in S510, and it can also be different from the second preamble sent by the terminal device in S545. In this way, the network device can recognize the check sequence.

[0268] As an example, S550 and S510 can be regarded as one action, that is, the terminal device can send S preambles in S time domain units out of P time domain units based on the first pattern (i.e., S510), and send the check sequence in the remaining time domain units (i.e., S550).

[0269] As another example, S550 and S545 can be regarded as one action, that is, the terminal device can send S preambles (i.e., the second preamble in S545) in S time domain units out of P time domain units based on the first pattern, and send the check sequence (i.e., S550) in the remaining time domain units.

[0270] As another example, S550 can be executed after S510 and S545.

[0271] In some examples, the position of the pattern period containing the PS time-domain elements used to transmit the check sequence within the radio frame is predetermined. For ease of understanding and description, the pattern period containing the PS time-domain elements used to transmit the check sequence will be referred to as the "check pattern period" below.

[0272] As an example, the position of the check pattern period in the radio frame can be agreed upon through predefinition, preconfiguration, network device configuration (e.g., via SSB or SIB messages) or other means.

[0273] For example, suppose a radio frame consists of two pattern periods. As an example, it is agreed that the check pattern period is the first pattern period in the radio frame. Thus, if the network device detects the check sequence in the first half of the radio frame, or does not detect the check sequence in the second half, the network device can determine that the terminal device and the network device have achieved time synchronization at the radio frame level. Conversely, if the network device does not detect the check sequence in the first half of the radio frame, or detects the check sequence in the second half, the network device can determine that there is an offset of one pattern period between the terminal device's pattern period and the network device's pattern period. An example of agreeing that the check pattern period is the second pattern period in the radio frame is similar to the above explanation; further examples will not be repeated.

[0274] For example, suppose a radio frame consists of three or more pattern periods. As an example, it is agreed that the check pattern period is the first pattern period in the radio frame. Thus, if the network device detects a check sequence in the first pattern period of the radio frame, the network device can determine that the terminal device and the network device have achieved time synchronization at the radio frame level. If the network device detects a check sequence in the Qth pattern period of the radio frame (e.g., Q is a positive integer greater than 1), the network device can determine that the pattern period of the terminal device is offset by Q-1 pattern periods from the pattern period of the network device. An example where the check pattern period is the last pattern period in the radio frame is similar to the above explanation; further examples will not be repeated.

[0275] To facilitate understanding, two examples of wireless frame-level time synchronization are presented below, referred to as Synchronization Example 1 and Synchronization Example 2, respectively.

[0276] Synchronization Example 1:

[0277] When executing S550, the terminal device and the network device do not achieve time synchronization at the radio frame level.

[0278] In some implementations, method 500 also includes: S560.

[0279] S560, when a check sequence is detected on P time-domain cells, the network device determines the second offset based on the position of the P time-domain cells in the radio frame.

[0280] For example, the second offset can be used to indicate the number of pattern periods offset between the pattern period of the network device and the pattern period of the terminal device on the radio frame. For instance, if the radio frame includes L pattern periods, the second offset can indicate that the pattern period of the network device and the pattern period of the terminal device are offset by 1, 2, ..., or L pattern periods on the radio frame. Wherein, L is an integer greater than 1.

[0281] As an example, if the radio frame includes L = 2 pattern periods, the aforementioned second offset can indicate that the pattern period of the network device and the pattern period of the terminal device are offset by 1 pattern period in the radio frame. As another example, if the radio frame includes L = 3 pattern periods, the aforementioned second offset can indicate that the pattern period of the network device and the pattern period of the terminal device are offset by 1 or 2 pattern periods in the radio frame.

[0282] For example, the second offset may be called a pattern period offset or other names, and this application does not limit the specific name of the second offset.

[0283] As an example, a network device can detect a check sequence on a subset of P time-domain units. For instance, the network device can perform detection on R time-domain units out of P time-domain units based on a first pattern, where a check sequence can be detected in time-domain units where a preamble was not detected.

[0284] As mentioned above, the pattern period to which the P time-domain units in the above S550 belong can be called the "verification pattern period".

[0285] In some examples, the check pattern period is conventionally located in the first pattern period of the radio frame. For example, assuming L=2, i.e., the radio frame consists of 2 pattern periods, the scenario shown in Synchronization Example 1 is that the network device detects the check sequence in the second half of the radio frame, i.e., the position of P time-domain units in the radio frame is "the second pattern period". The second offset can indicate that the pattern period of the network device is offset by 1 pattern period in the radio frame from the pattern period of the terminal device.

[0286] For example, assuming L is greater than or equal to 3, meaning the radio frame includes more than 3 pattern periods, the scenario shown in Synchronization Example 1 is that the network device detects a check sequence in the 2nd, 3rd, ..., or Lth pattern period of the radio frame; that is, the P time-domain units are located in the radio frame at the "2nd, 3rd, ..., or Lth pattern period". Accordingly, the second offset can indicate that the pattern period of the network device and the pattern period of the terminal device are offset by 1, 2, ..., or L-1 pattern periods in the radio frame. Alternatively, the second offset can indicate that the pattern period of the network device and the pattern period of the terminal device are offset by L-1, L-2, ..., or 1 pattern period in the radio frame.

[0287] In other examples, it is agreed that the check pattern period is located in the last pattern period of the radio frame. For example, assuming L=2, that is, the radio frame consists of 2 pattern periods, the scenario shown in Synchronization Example 1 is that the network device detects the check sequence in the first half of the radio frame, that is, the position of P time-domain units in the radio frame is "the second pattern period". The second offset can indicate that the pattern period of the network device is offset by 1 pattern period in the radio frame from the pattern period of the terminal device.

[0288] For example, assuming L is greater than or equal to 3, meaning the radio frame includes more than 3 pattern periods, the scenario shown in Synchronization Example 1 is that the network device detects a check sequence in the 1st, 2nd, ..., or L-1th pattern period of the radio frame; that is, the P time-domain units are located in the radio frame in the "1st, 2nd, ..., or L-1th pattern period". Accordingly, the second offset can indicate that the pattern period of the network device and the pattern period of the terminal device are offset by 1, 2, ..., or L-1 pattern periods in the radio frame. Alternatively, the second offset can indicate that the pattern period of the network device and the pattern period of the terminal device are offset by L-1, L-2, ..., or 1 pattern period in the radio frame.

[0289] In some further examples, it is agreed that the check pattern period is located in the Xth pattern period of the radio frame (X is a positive integer less than or equal to L). For example, the scenario shown in Synchronization Example 1 is that the network device detects the check sequence in the (X+1), (X+2), ..., or Lth pattern period of the radio frame, or in the 1st, 2nd, ..., or (X-1)th pattern period of the radio frame. That is, the P time-domain units are located in the radio frame in the "X+1th, X+2nd, ..., or Lth pattern period; or the 1st, 2nd, ..., or (X-1)th pattern period". Accordingly, the second offset can indicate that the pattern period of the network device is offset from the pattern period of the terminal device by 1, 2, ..., or LX pattern periods in the radio frame; or offset by X-1, X-2, ..., or 1 pattern period in the radio frame.

[0290] Based on the above scheme, if a network device detects P time-domain units, it indicates that time synchronization at the radio frame level has not been achieved between the network device and the terminal device. For example, assuming a radio frame consists of two pattern periods, and the parity check sequence is transmitted in the first pattern period (i.e., the first half of the frame), while the network device detects the parity check sequence in the second pattern period (i.e., the second half of the frame), the network device can determine the number of pattern periods offset between its pattern period and the terminal device's pattern period, i.e., the second offset. This scheme helps the network device and the terminal device achieve time synchronization at the radio frame level.

[0291] In some possible implementations, method 500 also includes: S565 and S570.

[0292] In step S565, the network device sends a second offset indication to the terminal device. Correspondingly, the terminal device receives the second offset indication from the network device.

[0293] In some examples, the indication information of the second offset mentioned above can be carried in the first information, or in other words, the first information can include the indication information of the second offset. In this way, S565 and S520 can be regarded as a single action.

[0294] As an example, the terminal device executes S510 and S550 simultaneously. After executing S510 and S560, the network device can send first information to the terminal device, which may include indication information of the second offset. Optionally, the first information may also include indication information of the first offset.

[0295] In other examples, the indication information for the second offset mentioned above can be carried in other information besides the first information. In this way, S565 and S520 can be regarded as two actions.

[0296] As an example, after executing S510, the network device can execute S520, which involves sending the first information to the terminal device. Further, the terminal device can execute S550, which involves sending a verification sequence to the network device. The network device can execute S560, which involves determining the second offset. Further, the network device can execute S565, which involves sending an indication of the second offset to the terminal device.

[0297] As another example, a network device can execute both S565 and S520 simultaneously. For instance, a network device can send a first message and a second offset indication message to a terminal device.

[0298] In step S568, the terminal device sends a third preamble to the network device based on the second offset and the second pattern. Correspondingly, the network device receives the preamble based on the first pattern.

[0299] For example, based on the second offset, the terminal device can align its radio frame with the network device's radio frame. Based on the second pattern, the terminal device can transmit S preambles (referred to as the third preamble in S568) in the S time-domain units of the aligned radio frame.

[0300] As an example, the third preamble can be one or more preambles sent by the terminal device based on the second offset and the second pattern in S568. Correspondingly, the network device can receive part or all of the preambles in the third preamble based on the first pattern.

[0301] As an example, S568 is executed after S510. Thus, the time-domain positions of the S time-domain units used to send the third preamble in S568 are located after the S time-domain units corresponding to the S preambles (including the first preamble) sent by the terminal device in S510.

[0302] The above section, combining S565 and S568, introduced synchronization example 1, which illustrates an example where the terminal device and network device fail to achieve time synchronization at the radio frame level when executing S550. The following section introduces synchronization example 2.

[0303] Synchronization Example 2:

[0304] When S550 is executed, the terminal device and the network device have already achieved time synchronization at the radio frame level.

[0305] In some implementations, method 500 also includes: S570.

[0306] S570, if a check sequence is detected on P time-domain units, the network device sends an identifier of the first preamble to the terminal device. Correspondingly, the terminal device receives the identifier of the first preamble from the network device.

[0307] For example, the identifier of the first preamble can be RAPID or other identifiers.

[0308] In some examples, the identifier of the first preamble can be carried in the first information, or in other words, the first information can include the identifier of the first preamble. Thus, S570 and S520 can be considered as a single action.

[0309] As an example, the terminal device executes both S510 and S550 simultaneously. After executing S510, the network device can send first information to the terminal device, which may include an identifier of a first preamble. Optionally, the first information may also include indication information of a first offset.

[0310] In other examples, the identifier of the first preamble can be carried in other information besides the first information. In this way, S570 and S520 can be regarded as two actions.

[0311] As an example, after executing S510, the network device can execute S520, which sends the first information to the terminal device. Further, the terminal device can execute S550, which sends a verification sequence to the network device. The network device can execute S570, which sends the identifier of the first preamble to the terminal device.

[0312] As another example, a network device can execute both S570 and S520 simultaneously. For instance, a network device can send a first message and an identifier of a first preamble to a terminal device.

[0313] In other examples, the identifier of the first preamble in S570 can be replaced with the identifier of another preamble (e.g., the identifier of the second preamble). For example, if the terminal device executes S550 while executing S545, the identifier of the first preamble in S570 can be replaced with the identifier of the second preamble.

[0314] As an example, a network device can detect a check sequence on a subset of P time-domain units. For instance, the network device can perform detection on R time-domain units out of P time-domain units based on a first pattern, where a check sequence can be detected in time-domain units where a preamble was not detected.

[0315] As mentioned above, the pattern period to which the P time-domain units in the above S550 belong can be called the "verification pattern period".

[0316] In some examples, the check pattern period is conventionally located in the first pattern period of the radio frame. For example, assuming L=2, that is, the radio frame consists of 2 pattern periods, the scenario shown in Synchronization Example 2 is that the network device detects the check sequence in the first half of the radio frame.

[0317] For example, assuming L is greater than or equal to 3, that is, the wireless frame includes more than 3 pattern periods, the scenario shown in Synchronization Example 2 is that the network device detects the check sequence on the first pattern period of the wireless frame.

[0318] In other examples, it is agreed that the check pattern period is located in the last pattern period of the radio frame. For example, assuming L=2, that is, the radio frame consists of 2 frames, the scenario shown in Synchronization Example 2 is that the network device detects the check sequence in the second half of the radio frame.

[0319] For example, assuming L is greater than or equal to 3, that is, the wireless frame includes more than 3 pattern periods, the scenario shown in Synchronization Example 2 is that the network device detects the check sequence on the Lth pattern period of the wireless frame.

[0320] In some further examples, it is agreed that the check pattern period is located in the Xth pattern period of the radio frame (X is a positive integer less than or equal to L). For example, the scenario shown in Synchronization Example 2 is that the network device detects the check sequence in the Xth pattern period of the radio frame.

[0321] Based on the above scheme, if the network device detects P time-domain units, it indicates that time synchronization at the radio frame level has been achieved between the network device and the terminal device. For example, assuming a radio frame consists of two pattern periods, and the parity check sequence is sent in the first pattern period (i.e., the first half of the frame), and the network device detects the parity check sequence in the first pattern period of the radio frame, then the network device can determine that time synchronization at the radio frame level has been achieved between the network device and the terminal device, and thus further send the preamble identifier to trigger the subsequent random access procedure.

[0322] In some possible implementations, method 500 also includes S575.

[0323] In step S575, the terminal device sends a random access message to the network device based on the identifier of the first preamble. Correspondingly, the network device receives the identifier of the first preamble.

[0324] As an example, the terminal device can determine whether the preamble corresponding to the identifier of the first preamble received in S570 is a preamble previously sent by the terminal device (e.g., before S570). If the preamble corresponding to the identifier is a preamble previously sent by the terminal device, the terminal device can send a random access message to the network device.

[0325] As an example, the random access message could be Msg3 in the four-step random access method, or it could be a message from a future proposed random access method.

[0326] As another example, the random access message could be Msg1 in a four-step random access method, MsgA in a two-step random access method, or a message from a future proposed random access method. Exemplarily, the random access message in this example can be used for time synchronization. The network device can determine information (e.g., first information) for time synchronization between the terminal device and the network device based on this random access message.

[0327] The above examples of time synchronization at the wireless frame level, combined with synchronization example 1 and synchronization example 2, illustrate relevant examples. For example, time synchronization at the wireless frame level can be understood as the alignment of the wireless frame headers, or in other words, the alignment of the starting positions of the wireless frames.

[0328] To facilitate understanding, the following example illustrates a specific instance of Method 500, using the PRACH transmission period as a radio frame, time domain unit groups as time slots, and time domain units as symbols.

[0329] As an example, a radio frame can be divided into M*N time slots. M can be a positive integer. Each time slot includes K symbols. N time slots can form a pattern period. That is, a radio frame can include M pattern periods.

[0330] In some examples, the terminal device can transmit a preamble using a second pattern (or, a transmit pattern) in each of the M pattern cycles. For example, the second pattern can be used to indicate the transmission of S preambles on S symbols out of P symbols. The network device can perform preamble detection using a first pattern (or, a detect pattern) in each of the M pattern cycles. For example, the first pattern can be used to indicate preamble detection on R symbols out of P symbols.

[0331] As an example, terminal devices and network devices can execute S510 to implement the above process.

[0332] Furthermore, the network device can determine the TA information based on the detected preamble (e.g., the aforementioned first preamble) and send the TA information to the terminal device.

[0333] As an example, network devices and terminal devices can execute the aforementioned S520 to achieve the above process.

[0334] Furthermore, the terminal device can adjust the PRACH transmission time based on TA information to achieve symbol-level time synchronization between the network device and the terminal device.

[0335] As an example, the terminal device can execute the aforementioned S530 to achieve the above process.

[0336] For example, there can be N*K possible symbol offsets within a pattern period, thus resulting in N*K third patterns (or decision patterns). For instance, the third pattern can indicate the number of preambles detected in each time slot of a pattern period; or, the third pattern can indicate the number of preamble symbols detected in each time slot of a pattern period. As an example, the third pattern can include N values, each corresponding to one of the N time slots in a pattern period. These N values ​​respectively indicate the number of preambles detected in the N time slots of a pattern period, or the number of preamble symbols detected in the N time slots of a pattern period.

[0337] For example, by designing the first and second patterns, it can be ensured that all N values ​​in each third pattern are non-zero. This way, regardless of the symbol offset between the terminal device's transmitting time-domain resources and the network device's receiving time-domain resources, the network device can detect at least a portion of the preamble transmitted by the terminal device. As another example, by designing the first and second patterns, it can be ensured that the N values ​​of any two third patterns out of the N*K third patterns are not identical. This establishes a one-to-one correspondence between the N*K third patterns and the N*K possible symbol offsets.

[0338] In some examples, the network device can determine the third pattern corresponding to the preamble sent by the terminal device by the number of preambles detected in each time slot of a pattern period, and determine the number of symbols offset between the terminal device's transmission time domain resources and the network device's reception time domain resources based on the one-to-one correspondence between N*K third patterns and N*K symbol offset cases.

[0339] As an example, a network device can execute the aforementioned S535 to achieve the above process.

[0340] Furthermore, the network device can send information to the terminal device indicating the number of symbols offset between the terminal device's transmission time domain resources and the network device's reception time domain resources (e.g., the aforementioned first offset indication information).

[0341] As an example, network devices and terminal devices can execute the aforementioned S540 to achieve the above process.

[0342] Furthermore, the terminal device can adjust the PRACH transmission time based on the first offset to achieve pattern period-level time synchronization between the network device and the terminal device.

[0343] As an example, the terminal device can execute the aforementioned S545 to achieve the above process.

[0344] To facilitate understanding, the following example uses PRACH transmission period as a radio frame, time domain unit group as time slot, and time domain unit as symbol as an example to introduce a specific example of Method 500 with specific parameters.

[0345] As an example, a radio frame can be divided into M*N time slots. For instance, the PRACH transmission period can be one radio frame.

[0346] For example, in an NR system, the length of a radio frame can be 10 milliseconds (ms). If the SCS is 15kHz, one radio frame can be divided into 2*5 time slots (i.e., M=2; N=5) or 1*10 time slots. If the SCS is 30kHz, one radio frame can be divided into 4*5 time slots or 5*4 time slots. And so on, without further examples.

[0347] Taking a 15kHz SCS in an NR system as an example, the number of sampling points in one time slot can be 15 * FFT points. Here, "FFT points" can also be simply referred to as "FFT". One time slot is divided into 15 symbols, and the length of each symbol can be one FFT.

[0348] As an example, one radio frame can include M pattern periods. Each pattern period can include N time slots. Each time slot can include K symbols of length one FFT (or, K symbols of length K FFT). Thus, each pattern period can include N*K symbols of length N*K FFT.

[0349] In some examples, the network device can use a pattern period as the period for detecting the preamble. A pattern period can include N time slots. Each time slot can include K FFT-length symbols. The network device can select a subset of symbols in each time slot for detection.

[0350] For example, the network device can perform preamble detection based on a first pattern. For instance, the first pattern may include a sequence d(0), d(1), ..., d(K-1). This sequence can instruct the network device whether to perform preamble detection on each symbol in each time slot. For example, d(0) being 0 indicates that no preamble detection is performed on the first symbol in each time slot. As another example, d(1) being 1 indicates that preamble detection is performed on the second symbol in each time slot.

[0351] For example, the first pattern may include the sequence d(0), d(1), ..., d(N*K-1). This sequence can instruct the network device whether to perform preamble detection on each symbol within a pattern period. For instance, d(0) being 0 indicates that no preamble detection is performed on the first symbol in the pattern period. Similarly, d(1) being 1 indicates that preamble detection is performed on the second symbol in the pattern period.

[0352] In some examples, the terminal device can use a pattern period as the period for transmitting the preamble. The length of a preamble in the time domain can be one FFT. The terminal device can transmit the preamble on a subset of symbols in each time slot within a pattern period.

[0353] For example, the terminal device can send a preamble based on a second pattern. For instance, the second pattern may include a sequence p(0), p(1), ..., p(N*K-1). This sequence can indicate whether the terminal device sends a preamble on each symbol within a pattern period. For example, p(0) being 0 indicates that no preamble is sent on the first symbol in the pattern period. As another example, p(1) being 1 indicates that a preamble is sent on the second symbol in the pattern period.

[0354] For example, the network device detects the preamble according to the first pattern in each time slot within a pattern period, and counts the number of preamble symbols detected in each time slot within the pattern period, resulting in a sequence s(0), s(1), ..., s(N-1). For example, s(0) can represent the number of preamble symbols detected in the first time slot within the pattern period. As an example, the above sequence can be called the third pattern.

[0355] It is understandable that within a pattern period, there can be N*K symbol offsets between the transmitting time-domain resources of the terminal device and the receiving time-domain resources of the network device. With N*K symbol offsets, the network device can obtain N*K third patterns. By designing the first and second patterns, it is possible to ensure that no two of the N*K third patterns are completely identical, and that the values ​​of all elements in any third pattern are not all zero.

[0356] Using the above scheme, network devices can quickly determine the number of symbols offset between the transmitting time domain resources of the terminal device and the receiving time domain resources of the network device based on N*K third patterns, that is, to achieve time synchronization at the symbol level and the pattern period level. See the example above for details, which will not be repeated here.

[0357] After time slot alignment, if M is greater than 1, there may be cases where the radio frames are not aligned. For example, the transmitting time domain resources of the terminal device and the receiving time domain resources of the network device may be offset by one or more pattern periods in the radio frame.

[0358] In some examples, the terminal device can transmit a check sequence within a pattern period, on a time domain unit outside the time domain unit where the second pattern indicates the transmission of the preamble. As an example, this check sequence can be used to determine the number of pattern periods offset between the terminal device's transmission time domain resources and the network device's reception time domain resources. Thus, by adjusting the timing of the terminal device's preamble transmission at the granularity of the pattern period, time synchronization at the radio frame level can be achieved. Detailed descriptions of the above examples can be found above, for example, examples S560, S565, and S568; and examples S570 and S575, which will not be repeated here.

[0359] To facilitate understanding, the following example uses a PRACH transmission period of one radio frame, a time-domain unit group as a time slot, and a time-domain unit as a symbol. Three specific examples of Method 500 are then presented, along with the first, second, and third patterns. These are denoted as Pattern Example 1 to Pattern Example 3, respectively.

[0360] Example of a pattern:

[0361] Taking a 15kHz SCS in an NR system as an example, one radio frame can be divided into 2*5 time slots. For example, one radio frame can include 2 pattern periods. Each pattern period can include 5 time slots. As an example, each time slot can include 15 symbols, so each pattern period can include 75 symbols. Table 3 shows an example of a possible second pattern.

[0362] Table 3

[0363] Time slot 0 Time slot 1 Time slot 2 Time slot 3 Time slot 4 000010010010111 000000000111000 000000111000000 000111000000000 111000010010010

[0364] Assuming that in Table 3, a value of 1 indicates that a preamble is sent, and a value of 0 indicates that a preamble is not sent. For example, this second pattern can instruct the terminal device to send a preamble on the 5th, 8th, 11th, 13th, 14th, 15th, 25th, 26th, 27th, 37th, 38th, 39th, 49th, 50th, 51st, 61st, 62nd, 63rd, 68th, 71st, and 74th symbols of each pattern cycle.

[0365] Assuming the first pattern instructs the network device to detect the preamble in the first three symbols of each time slot, the correspondence between the N*K symbol offsets between the terminal device's transmission time domain resources and the network device's reception time domain resources and the N*K third patterns can be shown in Table 4.

[0366] Table 4

[0367]

[0368]

[0369]

[0370] Referring to Table 4, in the "Second Pattern" column, the second pattern can include 75 bits, each corresponding to one of the 75 symbols in a pattern period. A bit of the second pattern being 1 indicates that the corresponding symbol is used to transmit the preamble; a bit of the second pattern being 0 indicates that the corresponding symbol is not used to transmit the preamble.

[0371] The network device can detect the preamble on symbols 1-3, 16-18, 31-33, 46-48, and 61-63 of each time slot. For example, when the symbol offset is 0, the bits corresponding to the symbol for which the network device detects the preamble are represented in bold. As an example, the values ​​of the first four groups of bold bits are all 0, and the values ​​of the fifth group of bold bits are all 1, so the third pattern corresponding to this case is "00003".

[0372] Furthermore, as shown in Table 4, not all 75 third patterns are 0, and no two of the 75 third patterns are exactly the same.

[0373] Example of a pattern:

[0374] Taking a 30kHz SCS in an NR system as an example, one radio frame can be divided into 5*4 time slots. For example, one radio frame can include 5 pattern periods. Each pattern period can include 4 time slots. As an example, each time slot can include 15 symbols, so each pattern period can include 20 symbols. Table 5 shows an example of a possible second pattern.

[0375] Table 5

[0376] Time slot 0 Time slot 1 Time slot 2 Time slot 3 111111111111111 000010001001000 011011101000000 011000000000110

[0377] Assuming that in Table 5, a value of 1 indicates that a preamble is sent, and a value of 0 indicates that a preamble is not sent. For example, this second pattern can instruct the terminal device to send a preamble on symbols 1-15, 20, 24, 27, 32, 33, 35, 36, 37, 39, 47, 48, 58, and 59 of each pattern cycle.

[0378] Assuming the first pattern instructs the network device to detect the preamble on the 3rd, 5th, 7th, and 9th symbols of each time slot, the correspondence between the N*K symbol offsets between the terminal device's transmission time domain resources and the network device's reception time domain resources and the N*K third patterns can be shown in Table 6.

[0379] Table 6

[0380]

[0381]

[0382] Referring to Table 6, in the "Second Pattern" column, the second pattern can include 60 bits, each corresponding to one of the six symbols in a pattern period. A bit of the second pattern being 1 indicates that the corresponding symbol is used to transmit the preamble; a bit of the second pattern being 0 indicates that the corresponding symbol is not used to transmit the preamble.

[0383] In this scenario, the network device can detect the preamble on the 3rd, 5th, 7th, and 9th symbols of each time slot. For example, when the symbol offset is 0, the bits corresponding to the symbols for which the network device detects the preamble are represented in bold. As an example, the values ​​of the first group of bold bits (corresponding to the 3rd, 5th, 7th, and 9th symbols in time slot 0) are all 1; two bits in the second group of bold bits (corresponding to the 3rd, 5th, 7th, and 9th symbols in time slot 1) have a value of 1; the values ​​of the third group of bold bits (corresponding to the 3rd, 5th, 7th, and 9th symbols in time slot 2) are all 1; and one bit in the fourth group of bold bits (corresponding to the 3rd, 5th, 7th, and 9th symbols in time slot 3) has a value of 1. Therefore, the third pattern corresponding to this case is "4241".

[0384] Furthermore, as shown in Table 6, not all 60 third patterns are 0, and no two of the 60 third patterns are exactly the same.

[0385] Example of a pattern:

[0386] Taking a 60kHz SCS in an NR system as an example, one radio frame can be divided into 8*5 time slots. For example, one radio frame can include 8 pattern periods. Each pattern period can include 5 time slots. As an example, each time slot can include 15 symbols, so each pattern period can include 75 symbols. Examples of the second pattern in pattern example 3 can be found in the relevant content of Table 3 above. In addition, examples of the first and second patterns can be found in the relevant content of Table 4 above, and will not be repeated here.

[0387] To facilitate understanding, the following example illustrates a specific instance of Method 500, using the PRACH transmission period as a radio frame, time domain unit groups as time slots, and time domain units as symbols.

[0388] In some examples, the terminal device can complete time synchronization in three steps. For instance, the terminal device can first achieve symbol-level time synchronization with the network device, or symbol alignment; then achieve pattern period-level time synchronization with the network device, or pattern period alignment; and finally achieve radio frame-level time synchronization with the network device, or PRACH transmission period alignment. The following section combines... Figure 6 Let me introduce it.

[0389] Figure 6This is a schematic flowchart of another communication method 600 provided in an embodiment of this application. Method 600 can be considered as a specific example of method 500. The following is in conjunction with... Figure 6 This section introduces the various operations of method 600.

[0390] S1, the terminal device sends a preamble on the PRACH using the second pattern. Correspondingly, the network device, based on the first pattern, detects the PRACH peak value in each time slot within a pattern period, and calculates the detected PRACH peak value and the corresponding TA information within the pattern period. For details, please refer to the previous sections, such as S510 and S520, which will not be repeated here.

[0391] As an example, if the PRACH peak detected by the network device is less than or equal to the preset PRACH peak threshold, the step returns to S1; otherwise, the step jumps to S2.

[0392] S2, the network device feeds back the detected maximum PRACH peak value and the corresponding TA information to the terminal device (e.g., via DCI, feeding back the TA information to the terminal device). Step skips to S3.

[0393] In step S3, the terminal device adjusts the transmission position of the PRACH based on the TA information. At this point, the terminal device and the network device can achieve symbol-level time synchronization; for example, the symbol header of the terminal device can be aligned with the symbol header of the network device. The terminal device can continue to transmit the preamble using the second pattern, and the network device can detect the PRACH peak value in each time slot within a pattern period based on the first pattern, and statistically analyze the detected PRACH peak value and the corresponding TA information within the pattern period. For details, please refer to the previous sections, such as the relevant content in S530, which will not be repeated here.

[0394] As an example, if the PRACH peak detected by the network device is less than or equal to (or replaced by, less than) the preset PRACH peak threshold, the step returns to S1; otherwise, the step jumps to S4.

[0395] S4, the network device determines a third pattern based on the number of symbols whose PRACH peak value is greater than or equal to (or replaced by, greater than) a preset PRACH peak value threshold in each time slot, and matches it with N*K third patterns to obtain the symbol offset between the time-frequency resources of the terminal device and the time-frequency resources of the network device. The specific determination process can be found in the preceding text, such as the relevant content in S535, and will not be repeated here.

[0396] As an example, if the network device cannot determine the symbol offset, the step returns to S3; otherwise, the TA information and symbol offset are fed back to the terminal device (e.g., via DCI), and the step jumps to S5.

[0397] The specific process by which network devices feed back TA information to terminal devices can be found in the previous text, such as the relevant content of S520 and S540, and will not be repeated here.

[0398] In step S5, the terminal device adjusts the transmission position corresponding to the PRACH based on the TA information and symbol offset. At this point, the terminal device and the network device can achieve time synchronization at the pattern period level. For example, the starting positions of the P time domain units of the terminal device can be aligned with the starting positions of the P time domain units of the network device. Alternatively, the starting positions of the N time domain unit groups of the terminal device can be aligned with the starting positions of the N time domain unit groups of the network device. The terminal device can continue to transmit the preamble using the second pattern, and the network device can detect the PRACH peak value in each time slot within a pattern period based on the first pattern, and statistically analyze the detected PRACH peak value and the corresponding TA information within the pattern period. For details, please refer to the previous sections, such as the relevant content in S545, which will not be repeated here.

[0399] As an example, if the PRACH peak detected by the network device is less than or equal to (or replaced by, less than) the preset PRACH peak threshold, the step returns to S1; otherwise, the step jumps to S6.

[0400] S6, the network device determines a third pattern based on the number of symbols whose PRACH peak value is greater than or equal to (or replaced by, greater than) a preset PRACH peak value threshold in each time slot, and matches it with N*K third patterns to obtain the symbol offset between the time-frequency resources of the terminal device and the time-frequency resources of the network device. The specific determination process can be found in the preceding text, such as the relevant content in S535, and will not be repeated here.

[0401] As an example, if the network device cannot determine the symbol offset, or if the symbol offset determined by the network device is not 0, the step returns to S3; if the network device determines that the symbol offset is 0, it indicates that the network device has determined that the pattern period has been aligned, and the step jumps to S7.

[0402] In S7, the terminal device can send a verification sequence. Correspondingly, the network device detects the verification sequence. For details, please refer to the previous text, such as the relevant content of S550, which will not be repeated here.

[0403] If the network device detects that the terminal device and the network device have not achieved time synchronization at the radio frame level, there is at least one pattern period offset between the terminal device's transmitting time domain resources and the network device's receiving time domain resources. The network device can feed back the TA information and the pattern period offset to the terminal device, and the process jumps to step S8. For details, please refer to the previous sections, such as S560 and S565, which will not be repeated here.

[0404] If the network device detects that the terminal device and the network device have achieved time synchronization at the radio frame level, the network device can send the TA information and the preamble identifier (or PRACH access identifier) ​​to the terminal device, and the process jumps to step S9. For details, please refer to the previous sections, such as S570 and S575, which will not be repeated here.

[0405] In step S8, the terminal device adjusts the transmission position corresponding to the PRACH based on the TA information and the pattern period offset. At this point, the terminal device and the network device can achieve time synchronization at the radio frame level, or, in other words, the terminal device and the network device can achieve complete alignment of time domain resources, or complete time synchronization. The terminal device can continue to transmit the preamble using the second pattern, and the network device can detect the PRACH peak value in each time slot within a pattern period based on the first pattern, and statistically analyze the detected PRACH peak value and the TA information corresponding to the PRACH peak value within the pattern period. For details, please refer to the previous text, such as the relevant content in S568, which will not be repeated here.

[0406] As an example, if the PRACH peak detected by the network device is less than or equal to (or replaced by, less than) the preset PRACH peak threshold, the step returns to S1; otherwise, the TA information and the identifier of the preamble (or PRACH access identifier) ​​are sent to the terminal device, and the step jumps to S9.

[0407] In S9, after receiving the identifier of the preamble, the terminal device continues to send the preamble according to the TA information. For example, in S9, the terminal device can send the preamble in a normal manner. For example, the terminal device can send the preamble based on the PRACH configuration instead of the second pattern.

[0408] Correspondingly, network devices can detect PRACH peaks normally. For example, network devices can detect PRACH peaks not based on the first pattern, but based on the PRACH configuration.

[0409] As an example, if the PRACH peak detected by the network device is less than or equal to (or replaced by, less than) a preset PRACH peak threshold, the step returns to S1; otherwise, a RAR is sent to the terminal device, which may include TA information.

[0410] Based on the above scheme, the terminal device can quickly complete the time synchronization between the terminal device and the network device through three adjustments, thereby shortening the time required for time synchronization, which helps to shorten the overall time for the terminal device to perform random access, and thus improves the efficiency of random access.

[0411] The following, combined with Figures 7 to 10 This application provides a detailed description of the communication device provided in the embodiments. The descriptions of the device embodiments correspond to the descriptions of the method embodiments; therefore, for content not described in detail, please refer to the above method embodiments. For the sake of brevity, some content will not be repeated.

[0412] This application embodiment can divide the communication device into functional modules according to the above method example. For example, each function can be divided into its own functional modules, or two or more functions can be integrated into one processing module. The integrated modules can be implemented in hardware, software, or a combination of both. The module division in this application embodiment is illustrative and only represents one logical functional division; other division methods may be used in actual implementation. The following description uses the division of functional modules according to each function as an example.

[0413] Figure 7 This is an exemplary block diagram of the communication device 10 provided in the embodiments of this application.

[0414] like Figure 7 As shown, for example, the communication device 10 may include a chip system 110, a memory 120, a bus 130, a power management module 140, or a transceiver 150, etc.

[0415] The chip system 110 can be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed through integrated logic circuits in the hardware of the chip system 110 or through software instructions.

[0416] By way of example and not limitation, chip system 110 may include circuitry or chips responsible for signal processing (such as a modem chip, also known as a baseband chip, or a system-on-chip (SoC) chip or system-in-package (SIP) chip containing a modem core).

[0417] Optionally, the chip system 110 may also include a memory (such as a cache) for storing instructions and data. In some embodiments, the memory in the chip system 110 is a cache memory. This memory can store instructions or data that the chip system 110 has just used or that are used repeatedly. If the chip system 110 needs to use the instruction or data again, it can retrieve it directly from this memory. This avoids repeated accesses, reduces the waiting time of the chip system 110, and thus improves the efficiency of the system.

[0418] In some embodiments, the chip system 110 may include one or more interfaces. Interfaces may include an inter-integrated circuit (I2C) interface, an inter-integrated circuit sound (I2S) interface, a pulse code modulation (PCM) interface, a universal asynchronous receiver / transmitter (UART) interface, a mobile industry processor interface (MIPI), a general-purpose input / output (GPIO) interface, a subscriber identity module (SIM) interface, and / or a universal serial bus (USB) interface, etc.

[0419] The memory 120 may include random access memory (RAM) and read-only memory (ROM). The memory 120 may store computer-readable and computer-executable code, including instructions that, when executed, cause the processor to perform the various functions of this application.

[0420] Optionally, the code may include instructions for implementing various aspects of the embodiments of this application, such as instructions for sending first information. The code may be stored in a non-transitory computer-readable medium such as system memory or other types of memory. In some cases, the code may not be directly executable by the chip system 110, but may enable a computer (e.g., at compile and execution time) to perform the functions of this application. In some cases, memory 120 may contain a basic I / O system that controls basic hardware or software operations, such as interaction with peripheral components or devices.

[0421] For example, the chip system 110 executes various functional applications and data processing of the communication device 10 by running instructions stored in the memory 120. For instance, when the communication device 10 transfers files with other devices (which may also be terminals or access network devices), the chip system 110 of the communication device 10 can call the computer-executable program code stored in the memory 120 to implement the communication method provided in the embodiments of this application.

[0422] In addition, the memory 120 can be integrated into the chip system 110 or independent of the chip system 110.

[0423] For example, bus 130 may be USB, used to support communication between various parts of communication device 10.

[0424] The power management module 140 is used to receive charging input from the charger. Optionally, the power management module 140 can also supply power to the communication device 10 while charging it (e.g., the battery module of the communication device 10). By way of example and not limitation, the power management module 140 can also supply power to other devices besides the communication device 10.

[0425] Transceiver 150 can communicate bidirectionally via one or more antennas, wired links, or wireless links. For example, transceiver 150 can represent a wireless transceiver and can communicate bidirectionally with another wireless transceiver. Transceiver 150 may also include a modem for modulating packets and providing the modulated packets to the antenna for transmission, and for demodulating packets received from the antenna. Transceiver 150 may include a receiver and a transmitter, the receiver performing the function of receiving information and the transmitter performing the function of transmitting information.

[0426] In some cases, a wireless device may include a single antenna. However, in other cases, a device may have more than one antenna, such as... Figure 7 Antennas 1 and 2 shown may be capable of simultaneously transmitting or receiving multiple wireless transmissions. Exemplarily, antennas 1 and 2 are used to transmit and receive electromagnetic wave signals. Each antenna in communication device 10 can be used to cover one or more communication frequency bands. Different antennas can also be multiplexed to improve antenna utilization. For example, antenna 1 can be multiplexed as a diversity antenna for a wireless local area network. In some other embodiments, the antennas can be used in conjunction with a tuning switch. Communication device 10 can transfer files to other devices via wireless communication functions.

[0427] In one design, the communication device 10 may correspond to the first communication device in the above method embodiment.

[0428] The communication device 10 can implement the steps or processes corresponding to the first communication device in the above method embodiment. The transceiver 150 can be used to perform the transmission and reception related operations of the first communication device in the above method embodiment, such as performing step S520 in the above method embodiment. The chip system 110 can be used to perform the processing related operations of the first communication device in the above method embodiment.

[0429] In another design, the communication device 10 may correspond to the second communication device in the above method embodiment.

[0430] The communication device 10 can implement the steps or processes corresponding to those performed by the second communication device in the above method embodiments. The transceiver 150 can be used to perform operations related to the transmission and reception of the second communication device in the above method embodiments, such as performing step S520 in the above method embodiments. The chip system 110 can be used to perform processing-related operations of the second communication device in the above method embodiments.

[0431] In a design where the communication device 10 corresponds to a second communication device (e.g., a terminal device), the communication device 10 may include, for example: Figure 7 The short-range communication module 164, sensor 161, display 162, or camera 163 shown are examples of such modules.

[0432] The short-range communication module 164 may include modules that support short-range communication, such as Wi-Fi and Bluetooth.

[0433] For example, sensor 161 may include pressure sensor, gyroscope sensor, barometric pressure sensor, magnetic sensor, accelerometer, distance sensor, proximity sensor, fingerprint sensor, temperature sensor, touch sensor, ambient light sensor, bone conduction sensor, etc.

[0434] For example, display 162 is used to display images, videos, etc. The display includes a display panel. The display panel may be a liquid crystal display (LCD), an organic light-emitting diode (OLED), an active-matrix organic light-emitting diode (AMOLED), a flexible light-emitting diode (FLED), a mini light-emitting diode (LED), a microLED, a microOLED, a quantum dot light-emitting diode (QLED), etc. For example, in this embodiment, the display can be used to display the interface required by the communication device 10. For example, the communication device 10 implements display functions through a graphics processing unit (GPU), a display, and an application processor. The GPU is a microprocessor for image processing, connected to the display and the application processor. The GPU is used to perform mathematical and geometric calculations for graphics rendering. The chip system 110 may include one or more GPUs that execute program instructions to generate or modify display information.

[0435] For example, camera 163 is used to acquire images, videos, etc.

[0436] Understandable, Figure 7 The structure shown does not constitute a specific limitation on the communication device 10. The specific structure of the terminal equipment and / or access network equipment can be referred to Figure 7 As shown. In some embodiments, the communication device 10 may also include a... Figure 7 This could mean having more or fewer components, combining some components, separating some components, or having different component arrangements. Or, Figure 7 Some of the components shown can be implemented in hardware, software, or a combination of both. Terminal devices and / or access network devices can be implemented in… Figure 7 The components were added or removed based on the given structure.

[0437] Figure 8 This is a schematic block diagram of the communication device 20 provided in the embodiments of this application.

[0438] like Figure 8As shown, the communication device 20 may include a baseband unit 210, which can communicate with external devices via a cellular radio frequency (RF) transceiver 220 (e.g., if the communication device 20 is a terminal device, the baseband unit 210 can communicate with access network devices via the cellular RF transceiver 220; or, if the communication device 20 is an access network device, the baseband unit 210 can communicate with terminal devices and / or core network devices via the cellular RF transceiver 220).

[0439] Exemplarily, baseband unit 210 may include a computer-readable medium / memory. Baseband unit 210 may be responsible for general processing, including the execution of software stored on the computer-readable medium / memory. When executed by baseband unit 304, the software causes baseband unit 210 to perform the various functions described above. The computer-readable medium / memory may also be used to store data manipulated by baseband unit 210 during software execution.

[0440] Optionally, the baseband unit 210 further includes a receiving unit 201, a management unit 202, and a transmitting unit 203. When the communication device 20 is used to implement the functions of the first communication device, the management unit 202 includes one or more of these components. Figure 8 The sub-units shown are as follows. For example, a detection sub-unit, which can be used in the above method embodiment to detect the first preamble based on the first pattern. Units within the management unit 201 can be stored in a computer-readable medium / memory and / or configured as hardware within the baseband unit 210. The management unit 201 can also be referred to as a processing unit. The receiving unit 201 and the transmitting unit 203 can be referred to as transceiver units.

[0441] When the communication device 20 is used to implement the functions of the first communication device in the above method embodiments, the receiving unit 201 is used to execute the receiving step of the first communication device, the sending unit 203 is used to execute the sending step of the first communication device, and the management unit 202 is used to execute the processing step of the first communication device.

[0442] For example, when the communication device 20 is used to implement the function of the first communication device in the above method embodiments, the management unit 202 is used to detect and obtain the first preamble based on the first pattern; the sending unit 203 is used to send the first information based on the first preamble, the first information being used for time synchronization between the network device and the terminal device.

[0443] For example, when the device 20 is used to perform Figure 5 When the method is in use, the receiving unit 201 can be used to execute the step of receiving information in the method; the management unit 202 can be used to execute the processing step in the method; and the sending unit 203 can be used to execute the step of sending information in the method.

[0444] When the communication device 20 is used to implement the functions of the second communication device in the above method embodiments, the receiving unit 201 is used to execute the receiving step of the second communication device, the sending unit 203 is used to execute the sending step of the second communication device, and the management unit 202 is used to execute the processing step of the second communication device.

[0445] For example, when the communication device 20 is used to implement the function of the second communication device in the above method embodiments, the sending unit 202 is used to send S preambles in S time domain units of P time domain units based on the second pattern, where P is a positive integer and S is a positive integer less than or equal to P; the receiving unit 201 is used to receive first information, which is used for time synchronization between the network device and the terminal device.

[0446] For example, when the communication device 20 is used to perform Figure 5 When the method is in use, the receiving unit 201 can be used to execute the step of receiving information in the method; the management unit 202 can be used to execute the processing step in the method; and the sending unit 203 can be used to execute the step of sending information in the method.

[0447] For a more detailed description of the receiving unit 201, management unit 202 and sending unit 203, please refer to the relevant descriptions in the above method embodiments, which will not be repeated here.

[0448] As an example and not a limitation, the chip system in this application is as follows: Figure 9 As shown, Figure 9 This is a schematic block diagram of the chip system 30 provided in the embodiments of this application. The chip system includes, but is not limited to, a modem chip, also known as a baseband chip, or a system-on-chip (SoC) chip or system-in-package (SIP) chip containing a modem core.

[0449] from Figure 9 As can be seen, the chip system (or processing system) includes a processor 310 and an input / output interface 330.

[0450] The processor 310 can be a processing circuit in a chip system (including at least one processor core, such as...). Figure 9(Shown as processor core 1 and processor core 2, etc.). Optionally, processor 310 can be coupled to memory 320 to call instructions in memory 320, enabling the chip system to implement the methods and functions of the various embodiments of this application. Input / output interface 330 can be an input / output circuit in the chip system, outputting information processed by the chip system, or inputting data or signaling information to be processed into the chip system for processing.

[0451] As one approach, the chip system is used to implement the operations performed by the first communication device or the second communication device in the various method embodiments described above.

[0452] For example, processor 310 is used to implement the processing-related operations performed by the first communication device or the second communication device in the above method embodiments, as described in the foregoing embodiments; input / output interface 330 is used to implement the sending and / or receiving-related operations performed by the first communication device or the second communication device in the above method embodiments, as described in the foregoing embodiments.

[0453] As an example and not a limitation, the chip system in this application is as follows: Figure 10 As shown, Figure 10 This is a schematic block diagram of the chip system 40 provided in an embodiment of this application.

[0454] from Figure 10 As can be seen, the chip system (or processing system) includes an input / output interface 410 and logic circuits 420. The input / output interface 410 can be an input / output circuit within the chip system, outputting processed information or inputting data or signaling information to be processed into the chip system for processing. For details, please refer to the description in the foregoing embodiments, for example, performing... Figure 5 The embodiment described above; the logic circuit 420 is used to execute the communication method described above, and can be referred to the description in the foregoing embodiment for details.

[0455] As one approach, the chip system is used to implement the operations performed by the first communication device or the second communication device in the various method embodiments described above.

[0456] For example, logic circuit 420 is used to implement processing-related operations performed by the first communication device or the second communication device in the above method embodiments; input / output interface 410 is used to implement sending and / or receiving-related operations performed by the first communication device or the second communication device in the above method embodiments.

[0457] This application also provides a computer-readable storage medium storing computer instructions for implementing the methods executed by the device in the above-described method embodiments.

[0458] For example, when the computer program is executed by a computer, it enables the computer to implement the methods executed by the first communication device or the second communication device in the various embodiments of the above methods.

[0459] This application also provides a computer program product comprising instructions that, when executed by a computer, implement the methods performed by the first communication device or the second communication device in the above-described method embodiments.

[0460] This application also provides a communication system, including the aforementioned first communication device and second communication device.

[0461] The explanations and beneficial effects of the relevant contents in any of the devices provided above can be found in the corresponding method embodiments provided above, and will not be repeated here.

[0462] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0463] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0464] In the several embodiments provided in this application, the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0465] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0466] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0467] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A communication method, characterized in that, include: Based on the first pattern, the first preamble is detected; Based on the first preamble, first information is sent, which is used for time synchronization between the network device and the terminal device. Wherein, the first preamble is sent with a second pattern, the second pattern being used to indicate that S preambles are sent in S time-domain units out of P time-domain units respectively, where P is a positive integer and S is a positive integer less than or equal to P. Wherein, the first pattern is used to indicate preamble detection in R time-domain units out of the P time-domain units, where R is a positive integer less than or equal to P; Wherein, after the S time-domain units have cyclically moved any number of time-domain units over the P time-domain units, there is at least one time-domain unit overlapping between the S time-domain units and the R time-domain units.

2. The method according to claim 1, characterized in that, The P time-domain units are N*K time-domain units in N time-domain unit groups, and each of the N time-domain unit groups includes K time-domain units, where N and K are positive integers; The method further includes: Based on the time-domain unit group to which the time-domain unit to which the first preamble belongs and N*K third patterns, a first offset is determined. The first offset is used to indicate the number of time-domain units offset between the receiving time-domain unit of the network device and the transmitting time-domain unit of the terminal device. The third patterns are used to indicate the number of preambles detected in each of the N time-domain unit groups. Any two third patterns among the N*K third patterns are different.

3. The method according to claim 2, characterized in that, The first information includes indication information for the first offset.

4. The method according to any one of claims 1 to 3, characterized in that, The method further includes: If a check sequence is detected on the P time-domain units, a second offset is determined based on the position of the P time-domain units in the radio frame. The second offset is used to indicate the number of pattern periods offset between the pattern period of the network device and the pattern period of the terminal device in the radio frame. The length of the pattern period is the length of the P time-domain units.

5. The method according to claim 4, characterized in that, The first information includes indication information for the second offset.

6. The method according to any one of claims 1 to 3, characterized in that, The method further includes: If a check sequence is detected on the P time-domain units, the identifier of the first preamble is sent.

7. The method according to any one of claims 1 to 6, characterized in that, The time-domain unit is a symbol, and / or, the time-domain unit group is a time slot.

8. A communication method, characterized in that, include: Based on the second pattern, S preambles are transmitted in S time-domain units out of P time-domain units, where P is a positive integer and S is a positive integer less than or equal to P. Receive first information, which is used for time synchronization between network devices and terminal devices.

9. The method according to claim 8, characterized in that, The P time-domain units are N*K time-domain units in N time-domain unit groups, and each of the N time-domain unit groups includes K time-domain units, where N and K are positive integers; The method further includes: Receive indication information of a first offset, wherein the first offset is used to indicate the number of time domain units offset between the transmitting time domain unit of the network device and the receiving time domain unit of the terminal device; Based on the first offset and the second pattern, a second preamble is sent.

10. The method according to claim 9, characterized in that, The indication information of the first offset is carried in the first information.

11. The method according to any one of claims 8 to 10, characterized in that, The method further includes: Send the verification sequence on the time domain units other than the S time domain units on the P time domain units; Receive indication information of a second offset, the second offset being used to indicate the number of pattern periods offset in the radio frame between the pattern period of the network device and the pattern period of the terminal device, the length of the pattern period being the length of the P time domain units; Based on the second offset and the second pattern, a third preamble is sent.

12. The method according to any one of claims 8 to 10, characterized in that, The method further includes: Send the verification sequence on the time domain units other than the S time domain units on the P time domain units; Receive the identifier of the first preamble, which belongs to the S preambles; Based on the identifier of the first preamble, a random access message is sent.

13. The method according to claim 11 or 12, characterized in that, The indication information of the second offset is carried in the first information, and / or the identifier of the first preamble is carried in the first information.

14. The method according to any one of claims 8 to 13, characterized in that, The time-domain unit is a symbol, and / or, the time-domain unit group is a time slot.

15. A communication device, characterized in that, It includes a processing unit and a transceiver unit, wherein, The processing unit is used to detect a first preamble based on a first pattern; and The transceiver unit is used to send first information based on the first preamble, the first information being used for time synchronization between the network device and the terminal device; Wherein, the first preamble is sent with a second pattern, the second pattern being used to indicate that S preambles are sent in S time-domain units out of P time-domain units respectively, where P is a positive integer and S is a positive integer less than or equal to P. Wherein, the first pattern is used to indicate preamble detection in R time-domain units out of the P time-domain units, where R is a positive integer less than or equal to P; Wherein, after the S time-domain units have cyclically moved any number of time-domain units over the P time-domain units, there is at least one time-domain unit overlapping between the S time-domain units and the R time-domain units.

16. The apparatus according to claim 15, characterized in that, The P time-domain units are N*K time-domain units in N time-domain unit groups, and each of the N time-domain unit groups includes K time-domain units, where N and K are positive integers; The processing unit is also used for: Based on the time-domain unit group to which the time-domain unit to which the first preamble belongs and N*K third patterns, a first offset is determined. The first offset is used to indicate the number of time-domain units offset between the receiving time-domain unit of the network device and the transmitting time-domain unit of the terminal device. The third patterns are used to indicate the number of preambles detected in each of the N time-domain unit groups. Any two third patterns among the N*K third patterns are different.

17. The apparatus according to claim 16, characterized in that, The first information includes indication information for the first offset.

18. The apparatus according to any one of claims 15 to 17, characterized in that, The processing unit is also used for: If a check sequence is detected on the P time-domain units, a second offset is determined based on the position of the P time-domain units in the radio frame. The second offset is used to indicate the number of pattern periods offset between the pattern period of the network device and the pattern period of the terminal device in the radio frame. The length of the pattern period is the length of the P time-domain units.

19. The apparatus according to claim 18, characterized in that, The first information includes indication information for the second offset.

20. The apparatus according to any one of claims 15 to 17, characterized in that, The transceiver unit is also used for: If a check sequence is detected on the P time-domain units, the identifier of the first preamble is sent.

21. The apparatus according to any one of claims 15 to 20, characterized in that, The time-domain unit is a symbol, and / or, the time-domain unit group is a time slot.

22. A communication device, characterized in that, Including transceiver units, among which, The transceiver unit is used to transmit S preambles in S time-domain units out of P time-domain units, based on the second pattern, where P is a positive integer and S is a positive integer less than or equal to P. The transceiver unit is further configured to receive first information, which is used for time synchronization between the network device and the terminal device.

23. The apparatus according to claim 22, characterized in that, The P time-domain units are N*K time-domain units in N time-domain unit groups, and each of the N time-domain unit groups includes K time-domain units, where N and K are positive integers; The transceiver unit is also used for: Receive indication information of a first offset, wherein the first offset is used to indicate the number of time domain units offset between the transmitting time domain unit of the network device and the receiving time domain unit of the terminal device; Based on the first offset and the second pattern, a second preamble is sent.

24. The apparatus according to claim 23, characterized in that, The indication information of the first offset is carried in the first information.

25. The apparatus according to any one of claims 22 to 24, characterized in that, The transceiver unit is also used for: Send the verification sequence on the time domain units other than the S time domain units on the P time domain units; Receive indication information of a second offset, the second offset being used to indicate the number of pattern periods offset in the radio frame between the pattern period of the network device and the pattern period of the terminal device, the length of the pattern period being the length of the P time domain units; Based on the second offset and the second pattern, a third preamble is sent.

26. The apparatus according to any one of claims 22 to 24, characterized in that, The transceiver unit is also used for: Send the verification sequence on the time domain units other than the S time domain units on the P time domain units; Receive the identifier of the first preamble, which belongs to the S preambles; Based on the identifier of the first preamble, a random access message is sent.

27. The apparatus according to claim 25 or 26, characterized in that, The indication information of the second offset is carried in the first information, and / or the identifier of the first preamble is carried in the first information.

28. The apparatus according to any one of claims 22 to 27, characterized in that, The time-domain unit is a symbol, and / or, the time-domain unit group is a time slot.

29. A communication device, characterized in that, include: At least one processor, the at least one processor being configured to execute a computer program or instructions to cause the method of any one of claims 1 to 14 to be performed.

30. The communication device according to claim 29, characterized in that, The communication device further includes a memory for storing the computer program or the instructions.

31. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program or instructions, and when the computer program or instructions are run, the method of any one of claims 1 to 14 is performed.

32. A computer program product, characterized in that, Includes a computer program or instructions, which, when executed, implement the method as described in any one of claims 1 to 14.

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