Communication method and device, terminal and network equipment

Abstract

Provided are a communication method and apparatus, a terminal and a network device, the method being applied to the terminal, the terminal stationing at a first network device, the method comprising: sending a first lead code to a second network device before a first sending time by an estimated time advance of the second network device; the pre-estimated time advance is advanced at the second sending time, and a first message is sent to the second network equipment on a physical uplink shared channel PUSCH corresponding to the first lead code; wherein the interval between the second sending time and the first sending time is first preset time. According to the invention, the network equipment can be quickly switched.

Description

Technical Field

[0001] This application relates to the field of communication technologies, and in particular, to a communication method, apparatus, terminal, and network device. Background Art

[0002] Both the coverage range and orbital altitude of network devices can affect the quality of terminal services. Therefore, by leveraging the different coverage ranges and latency characteristics of network devices, it is possible to switch between network devices to ensure service continuity and reliability.

[0003] However, during the handover process of the terminal between network devices, there are problems such as a long signal propagation distance, a long processing time due to signal demodulation and readjustment, the signal passing through multiple nodes, and a long terminal response time, resulting in a large latency when the terminal switches between network devices. Summary of the Invention

[0004] This application provides a communication method, apparatus, terminal, and network device that can quickly perform handover of network devices.

[0005] In a first aspect, a communication method is proposed, which is applied to a terminal that camps on a first network device. The method includes:

[0006] Advance the estimated time advance of a second network device by a second network device at a first transmission time, and send a first preamble to the second network device;

[0007] Advance the estimated time advance at a second transmission time, and send a first message to the second network device on a physical uplink shared channel PUSCH corresponding to the first preamble; wherein, the second transmission time is separated from the first transmission time by a first preset time.

[0008] In an implementable manner, the sending the first preamble to the second network device includes:

[0009] Send the first preamble to the second network device according to preamble configuration information, where the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity, the first preamble is one of the at least one preamble, and the first transmission time of the first preamble is one of the at least one random access opportunity.

[0010] In an implementable manner, the first preset time is predefined, or the first preset time is sent by the first network device.

[0011] In an implementable manner, the first message is one of the following: a radio resource control RRC connection establishment complete message, an RRC reconstruction complete message, a handover complete message, an RRC reconfiguration complete message, or a redirection complete message.

[0012] In one implementable manner, before sending the first preamble to the second network device, the method further includes:

[0013] Sending a second message to the first network device;

[0014] Receiving a third message from the first network device, where the third message includes the estimated timing advance.

[0015] In one implementable manner, the third message includes wireless configuration information configured by the second network device for the terminal.

[0016] In one implementable manner, the third message further includes frequency point information of the second network device.

[0017] In one implementable manner, the third message further includes a first temporary terminal identifier of the terminal, where the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is a temporary identifier re - assigned by the second network device to the terminal.

[0018] In one implementable manner, the preamble configuration information is obtained by one of the following methods:

[0019] Receiving a system message broadcast by the second network device, where the system message includes the preamble configuration information;

[0020] The third message further includes a system message of the second network device, where the system message includes the preamble configuration information;

[0021] The third message further includes the preamble configuration information.

[0022] In one implementable manner, the third message further includes at least one of the following parameters: a first temporary terminal identifier of the terminal, ephemeris information of the second network device, PUSCH configuration information for transmitting the first message, sub - carrier spacing information of the second network device, or preamble sequence number information; where,

[0023] The preamble sequence number information is used to indicate the first preamble, and the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is a temporary identifier re - assigned by the second network device to the terminal.

[0024] In one implementable manner, before sending the first preamble to the second network device, the method further includes:

[0025] Sending a second message to the first network device;

[0026] Receive a third message from the first network device, where the third message includes ephemeris information of the second network device;

[0027] Determine a predicted timing advance of the second network device based on the ephemeris information of the second network device.

[0028] In an implementable manner, the terminal obtains preamble configuration information in one of the following ways:

[0029] Receive a system message broadcast by the second network device, where the system message includes the preamble configuration information;

[0030] The third message further includes a system message of the second network device, where the system message includes the preamble configuration information;

[0031] The third message further includes the preamble configuration information.

[0032] In an implementable manner, the third message further includes at least one of the following parameters: wireless configuration information configured by the second network device for the terminal, frequency point information of the second network device, a first temporary terminal identifier of the terminal, where the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is a temporary identifier re - assigned by the second network device to the terminal.

[0033] In an implementable manner, the third message further includes at least one of the following parameters: PUSCH configuration information for transmitting the first message, sub - carrier spacing information of the second network device, or preamble sequence number information, where the preamble sequence number information is used to indicate the first preamble.

[0034] In an implementable manner, the second message includes at least one of the following parameters: location information of the terminal, preset network device information, or service type information.

[0035] In an implementable manner, the second message is one of the following: an RRC connection establishment request message, an RRC re - establishment request message, a handover request message, or a redirection request message.

[0036] In an implementable manner, the third message is one of the following: an RRC connection establishment message, an RRC connection re - establishment message, a handover command message, or a redirection command message.

[0037] In an implementable manner, after sending a first message to the second network device on a physical uplink shared channel PUSCH corresponding to the first preamble, the method further includes:

[0038] Receive a first timing advance from the second network device.

[0039] In one implementable manner, the orbital altitude of the first network device is different from that of the second network device.

[0040] In a second aspect, a communication method is provided, which is applied to a second network device. The method includes:

[0041] Receive a first preamble from a terminal; the terminal camps on a first network device, and the first preamble is sent at a first transmission time advance by an estimated time advance of the second network device;

[0042] Determine timing offset information according to an actual reception time window of the first preamble, where the timing offset information is used to indicate a time offset between the actual reception time window of the first preamble and a preset reception time window of the first preamble;

[0043] Receive a first message on a physical uplink shared channel PUSCH corresponding to the first preamble according to the timing offset information; the first message is sent at a second transmission time advance by the estimated time advance, and on the PUSCH, the second transmission time is separated from the first transmission time by a first preset time.

[0044] In one implementable manner, the first message is at least one of the following: an RRC connection establishment completion message, an RRC reestablishment completion message, a handover completion message, an RRC reconfiguration completion message, or a redirection completion message.

[0045] In one implementable manner, before receiving the first preamble from the terminal, the method further includes:

[0046] Receive a terminal access request message from the first network device;

[0047] Send a terminal access request response message to the first network device, where the terminal access request response message includes the estimated time advance of the second network device;

[0048] Wherein, the estimated time advance of the second network device is obtained according to the location information of the terminal.

[0049] In one implementable manner, before receiving the first preamble from the terminal, the method further includes:

[0050] Receive a terminal access request message from the first network device;

[0051] Send a terminal access request response message to the first network device, where the terminal access request response message includes the ephemeris information of the second network device.

[0052] In one possible implementation, the terminal access request response message further includes: the system message of the second network device; wherein,

[0053] The system message includes preamble configuration information, the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity, the first preamble is one of the at least one preamble, and the first transmission time of the first preamble is one of the at least one random access opportunity.

[0054] In one possible implementation, the terminal access request response message further includes preamble configuration information; wherein, the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity, the first preamble is one of the at least one preamble, and the first transmission time of the first preamble is one of the at least one random access opportunity.

[0055] In one possible implementation, the terminal access request response message further includes at least one of the following parameters: the first temporary terminal identifier of the terminal, the PUSCH configuration information for transmitting the first message, the subcarrier spacing information of the second network device, the wireless configuration information configured by the second network device for the terminal, the frequency point information of the second network device, or the preamble sequence number information; wherein,

[0056] The preamble sequence number information is used to indicate the first preamble, and the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or the temporary identifier re-assigned by the second network device to the terminal.

[0057] In one possible implementation, after receiving the first message on the physical uplink shared channel PUSCH corresponding to the first preamble according to the timing offset information, the method further includes:

[0058] Sending a first timing advance to the terminal.

[0059] In one possible implementation, the orbital altitude of the first network device is different from that of the second network device.

[0060] In a third aspect, a communication method is provided, which is applied to a first network device, and the method includes:

[0061] Sending a third message to the terminal, the third message includes information for the terminal to determine the estimated timing advance of the second network device, and the information for the terminal to determine the estimated timing advance of the second network device includes at least one of the estimated timing advance of the second network device or the ephemeris information of the second network device;

[0062] The third message further includes at least one of the following parameters: a first temporary terminal identifier of the terminal, wireless configuration information configured by the second network device for the terminal, frequency point information of the second network device, PUSCH configuration information for transmitting the first message, subcarrier spacing information of the second network device, or preamble sequence number information; wherein,

[0063] The preamble sequence number information is used to indicate a first preamble, and the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is a temporary identifier re-assigned by the second network device to the terminal.

[0064] In one implementable manner, the third message further includes system messages of the second network device; wherein,

[0065] The system messages include preamble configuration information, and the preamble configuration information is used to indicate at least one preamble and at least one random access occasion.

[0066] In one implementable manner, the third message further includes preamble configuration information; wherein, the preamble configuration information is used to indicate at least one preamble and at least one random access occasion.

[0067] In one implementable manner, before sending the third message to the terminal, the method further includes:

[0068] Receiving a second message from the terminal;

[0069] Sending a terminal access request message to the second network device;

[0070] Receiving a terminal access request response message from the second network device, where the terminal access request response message includes an estimated time advance of the second network device.

[0071] In one implementable manner, before sending the third message to the terminal, the method further includes:

[0072] Receiving a second message from the terminal;

[0073] Sending a terminal access request message to the second network device;

[0074] Receiving a terminal access request response message from the second network device, where the terminal access request response message includes ephemeris information of the second network device.

[0075] In one implementable manner, the terminal access request response message further includes: system messages of the second network device; wherein,

[0076] The system message includes preamble configuration information, where the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity. The first preamble is one of the at least one preambles, and the first transmission time of the first preamble is one of the at least one random access opportunities.

[0077] In an implementable manner, the terminal access request response message further includes preamble configuration information; wherein, the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity. The first preamble is one of the at least one preambles, and the first transmission time of the first preamble is one of the at least one random access opportunities.

[0078] In an implementable manner, the terminal access request response message further includes at least one of the following parameters: the first temporary terminal identifier of the terminal, the wireless configuration information configured by the second network device for the terminal, the frequency point information of the second network device, the PUSCH configuration information for transmitting the first message, the subcarrier spacing information of the second network device, or the preamble sequence number information; wherein,

[0079] The preamble sequence number information is used to indicate the first preamble, and the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is the temporary identifier re - assigned by the second network device to the terminal.

[0080] In an implementable manner, the second message includes at least one of the following parameters: the location information of the terminal, the preset network device information, or the service type information.

[0081] In an implementable manner, the second message is one of the following: an RRC connection establishment request message, an RRC re - establishment request message, a handover request message, or a redirection request message.

[0082] In an implementable manner, the third message is one of the following: an RRC connection establishment message, an RRC connection re - establishment message, a handover command message, or a redirection command message. In an implementable manner, the orbital altitude of the first network device is different from the orbital altitude of the second network device.

[0083] Fourthly, a communication device is proposed, which is applied to a terminal. The terminal camps on a first network device. The device includes:

[0084] A sending module, configured to advance the estimated time advance of the second network device by a first time advance at a first transmission time, and send a first preamble to the second network device.

[0085] The sending module is further configured to advance the estimated time advance amount at a second sending time, and send a first message to the second network device on a physical uplink shared channel PUSCH corresponding to the first preamble; wherein, the second sending time and the first sending time are separated by a first preset time. In a fifth aspect, a communication device is proposed, which is applied to a second network device, and the device includes:

[0086] A receiving module, configured to receive a first preamble from a terminal; the terminal camps on a first network device, and the first preamble is sent by advancing the estimated time advance amount of the second network device at a first sending time;

[0087] A processing module, configured to determine timing offset information according to an actual reception time window of the first preamble, where the timing offset information is used to indicate a time offset amount between the actual reception time window of the first preamble and a preset reception time window of the first preamble;

[0088] The receiving module is further configured to receive a first message on a physical uplink shared channel PUSCH corresponding to the first preamble according to the timing offset information; the first message is sent by advancing the estimated time advance amount at a second sending time, and on the PUSCH, the second sending time and the first sending time are separated by a first preset time.

[0089] In a sixth aspect, a communication device is proposed, which is applied to a first network device, and the device includes:

[0090] A sending module, configured to send a third message to a terminal, where the third message includes information for the terminal to determine the estimated time advance amount of the second network device, and the information for the terminal to determine the estimated time advance amount of the second network device includes at least one of the estimated time advance amount of the second network device or ephemeris information of the second network device;

[0091] The third message further includes at least one of the following parameters: a first temporary terminal identifier of the terminal, radio configuration information configured by the second network device for the terminal, frequency point information of the second network device, PUSCH configuration information for transmitting the first message, subcarrier spacing information of the second network device, or preamble sequence number information; wherein,

[0092] The preamble sequence number information is used to indicate the first preamble, and the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is a temporary identifier re-assigned by the second network device to the terminal.

[0093] In a seventh aspect, a terminal is proposed, including: a processor, and a memory communicatively connected to the processor;

[0094] The memory stores computer-executable instructions;

[0095] The processor executes the computer-executable instructions stored in the memory to implement the method described in the first aspect and the implementable ways of the first aspect.

[0096] In an eighth aspect, a second network device is proposed, including: a processor, and a memory communicatively connected to the processor;

[0097] The memory stores computer-executable instructions;

[0098] The processor executes the computer-executable instructions stored in the memory to implement the method described in the second aspect and the implementable ways of the second aspect.

[0099] In a ninth aspect, a first network device is proposed, including: a processor, and a memory communicatively connected to the processor;

[0100] The memory stores computer-executable instructions;

[0101] The processor executes the computer-executable instructions stored in the memory to implement the method described in the third aspect and the implementable ways of the third aspect.

[0102] In a tenth aspect, a computer-readable storage medium is proposed. The computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are executed by a processor, they are used to implement the method described in any one of the first aspect to the third aspect and the implementable ways of any one of the first aspect to the third aspect.

[0103] In an eleventh aspect, a computer program product is proposed, including a computer program, and when the computer program is executed by a processor, it implements the method described in any one of the first aspect to the third aspect and the implementable ways of any one of the first aspect to the third aspect.

[0104] For the communication method, device, terminal, and network device provided in this application, before the terminal switches to the second network device through the first network device, the terminal obtains the estimated time advance of the second network device. The terminal can perform uplink pre-synchronization with the second network device through this estimated time advance. Thus, the terminal sends a first preamble and a first message to the second network device through the estimated time advance of the second network device, so that the second network device can accurately receive the first message, accelerate the access process of the terminal in the second network device, and reduce the delay of the terminal switching between base stations. Description of the Drawings

[0105] The accompanying drawings herein are incorporated into and constitute a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0106] Figure 1 It is a structural diagram of a communication system shown in an embodiment of the present application;

[0107] Figure 2 It is a schematic flowchart of a communication method shown in an embodiment of the present application;

[0108] Figure 3 It is a schematic flowchart of a communication method shown in another embodiment of the present application;

[0109] Figure 4 It is a schematic flowchart of a communication method shown in another embodiment of the present application;

[0110] Figure 5 It is a schematic flowchart of a communication method shown in another embodiment of the present application;

[0111] Figure 6 It is a schematic block diagram of a communication device shown in an embodiment of the present application;

[0112] Figure 7 It is a schematic block diagram of a communication device shown in another embodiment of the present application;

[0113] Figure 8 It is a schematic block diagram of a communication device shown in another embodiment of the present application;

[0114] Figure 9 It is a schematic block diagram of a communication device shown in an embodiment of the present application.

[0115] Through the above accompanying drawings, specific embodiments of the present application have been shown, and there will be more detailed descriptions hereinafter. These drawings and written descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. Detailed Description of the Embodiments

[0116] Here, the exemplary embodiments will be described in detail, and the examples are shown in the accompanying drawings. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0117] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: Long Term Evolution (LTE) systems, LTE Frequency Division Duplex (FDD) systems, LTE Time Division Duplex (TDD), Universal Mobile Telecommunication System (UMTS), Worldwide Interoperability for Microwave Access (WiMAX) communication systems, future 5th Generation (5G) communication systems or new radio Access Technology (NR), vehicle-to-X (V2X), where V2X can include vehicle to network (V2N), vehicle to vehicle (V2V), vehicle to infrastructure (V2I), vehicle to pedestrian (V2P), etc., Long Term Evolution-Vehicle (LTE-V), vehicle networking, machine type communication (MTC), Internet of Things (IoT), Long Term Evolution-Machine (LTE-M), Machine to Machine (M2M), etc.

[0118] As Figure 1 shown, the communication system may include network devices, such as Figure 1 the network devices 110 and 120 shown; the communication system may further include at least one terminal, such as Figure 1 the terminal 130 shown. Among them, the terminal 130 may be mobile or fixed. The terminal 130 may access the network device 110 or access the network device 120.

[0119] The network devices 110 and 120 in the embodiments of the present disclosure are entities on the network side for transmitting or receiving signals, and the network devices can be network-side devices. For example, the network devices 110 and 120 can be evolved NodeBs (eNBs), transmission reception points (TRPs), next generation NodeBs (gNBs) in the NR system, base stations in other future mobile communication systems, or access nodes in a wireless fidelity (WiFi) system, etc. The embodiments of the present disclosure do not limit the specific technologies and specific device forms adopted by the network devices.

[0120] The network devices 110 and 120 provided in the embodiments of the present disclosure can be composed of a central unit (CU) and a distributed unit (DU). Among them, the CU can also be called a control unit. Adopting the CU-DU structure can split the protocol layers of the network device, such as a base station. The functions of some protocol layers are centrally controlled by the CU, and the functions of the remaining part or all protocol layers are distributed in the DU, and the DU is centrally controlled by the CU.

[0121] The terminal 130 in the embodiments of the present disclosure is an entity on the user side for receiving or transmitting signals, such as a mobile phone. The terminal can also be called a terminal, a user equipment (UE), a mobile station (MS), a mobile terminal (MT), a user-side device, etc. The terminal can be an automobile with communication functions, a smart car, a mobile phone, a wearable device, a tablet computer (Pad), a computer with wireless transceiver functions, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical surgery, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, etc.

[0122] In some embodiments, network devices 110 and 120 may be satellites. For example, network devices 110 and 120 may be satellites in different orbits.

[0123] In some embodiments, the terminal 130 accesses network device 110 and can switch to access network device 120 while staying under network device 110 to communicate with network device 120.

[0124] Embodiments of the present disclosure do not limit the specific technologies and specific device forms adopted by the terminal / network device.

[0125] The embodiments of the present disclosure are not exhaustive. They are only illustrations of some embodiments and do not constitute specific limitations on the protection scope of the present disclosure. Without contradiction, each step in an embodiment can be implemented as an independent embodiment, and the steps can be combined arbitrarily. For example, the solution after removing some steps in an embodiment can also be implemented as an independent embodiment, and the order of the steps in an embodiment can be arbitrarily exchanged. Additionally, the optional implementation manners in an embodiment can be combined arbitrarily; furthermore, the embodiments can be combined arbitrarily. For example, some or all of the steps of different embodiments can be combined arbitrarily, and an embodiment can be combined arbitrarily with the optional implementation manners of other embodiments. In each embodiment of the present disclosure, if there is no special description and logical conflict, the terms and / or descriptions among the embodiments are consistent and can be cited from each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0126] It can be understood that the communication system described in the embodiments of the present disclosure is for more clearly illustrating the technical solutions of the embodiments of the present disclosure and does not constitute a limitation on the technical solutions provided by the embodiments of the present disclosure. Those of ordinary skill in the art know that with the evolution of the system architecture and the emergence of new service scenarios, the technical solutions provided by the embodiments of the present disclosure are equally applicable to similar technical problems.

[0127] It can be understood that in the embodiments of the present application, "for indicating" may include direct indication and indirect indication, and may also include explicit indication and implicit indication. If the information indicated by a certain piece of information is called the information to be indicated, then in the specific implementation process, there are many ways to indicate the information to be indicated. For example, but not limited to, the information to be indicated can be directly indicated, such as the information to be indicated itself or the index of the information to be indicated, etc. The information to be indicated can also be indirectly indicated by indicating other information, where there is an association relationship between the other information and the information to be indicated. It is also possible to only indicate a part of the information to be indicated, while the other parts of the information to be indicated are known or pre-agreed. For example, it is also possible to implement the indication of the information to be indicated by relying on a pre-agreement (such as protocol regulations) on the existence of a certain cell, thereby reducing the indication overhead to a certain extent.

[0128] It can be understood that in the embodiments shown below, the first, second, and various numerical numbers are only for the convenience of description and are not used to limit the scope of the embodiments of the present application. For example, to distinguish different indication information, different time intervals, etc.

[0129] It can be understood that the "preset value" can be implemented by pre-saving corresponding codes, tables, or other ways that can be used to indicate relevant information in a device (for example, including terminal devices and IMS, P-CSCF). The present application does not limit its specific implementation method. Among them, "saving" may mean saving in one or more memories. One or more memories can be set separately, or can be integrated in a codec or decoder, a processor, or a communication device. One or more memories can also be partially set separately and partially integrated in a decoder, a processor, or a communication device. The type of memory can be any form of storage medium, and the present application does not limit this.

[0130] It can be understood that the "protocol" involved in the embodiments of the present application may refer to standard protocols in the communication field. For example, it may include LTE protocols, NR protocols, and related protocols applied to future communication systems. The present application does not limit this.

[0131] It can be understood that "at least one" means one or more, and "a plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one (item)" or similar expressions refer to any combination of these items, including any combination of single item or plural items. For example, at least one (item) of a, b, and c can represent: a, or b, or c, or a and b, or a and c, or b and c, or a, b, and c. Where a, b, and c can be single or multiple respectively.

[0132] It can be understood that in the embodiments of the present application, descriptions such as "when...", "in the case of...", "if", and "when" all refer to that in a certain objective situation, the device (such as a terminal device or a network device) will perform corresponding processing, which does not limit the time, and does not require the device (such as a terminal device or a network device) to have a judgment action when implementing, nor does it mean that there are other limitations.

[0133] It can be understood that for the convenience of describing the embodiments of the present application, without special explanation, the message names involved are all message names in NR. However, it can be understood that these message names are only examples for easy understanding and should not constitute any limitation to the present application. The present application does not exclude the possibility of defining other message names in future protocols to replace the message names listed in the present application to achieve the same or similar functions. In addition, taking the message names in NR as examples to illustrate the embodiments of the present application should not constitute any limitation to the scenarios applicable to the method provided by the present application.

[0134] It can be understood that multiple embodiments are described in detail below in conjunction with multiple flowcharts. However, it should be understood that the relevant descriptions of these flowcharts and their corresponding embodiments are only examples for easy understanding and should not constitute any limitation to the present application. Each step in each flowchart is not necessarily required to be executed. For example, some steps can be skipped. And the execution order of each step is not fixed and unchanged, nor is it limited to that shown in the figure. The execution order of each step should be determined according to its function and internal logic.

[0135] In addition, each element, each row, or each column in the table of the embodiments of the present disclosure can be implemented as an independent embodiment, and any combination of any element, any row, and any column can also be implemented as an independent embodiment.

[0136] The method provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0137] It should be understood that the following is only for easy understanding and illustration, and the method provided by the embodiments of the present application will be described in detail by taking the interaction between a terminal device and a network device as an example. However, this should not impose any limitation on the execution entity of the method provided by the present application. For example, the terminal device shown in the following embodiments can be replaced by components (such as chips or circuits) configured in the terminal device, etc. The network device shown in the following embodiments can also be replaced by components (such as chips or circuits) configured in the network device, etc.

[0138] The following embodiments do not particularly limit the specific structure of the execution entity of the method provided by the embodiments of the present application. As long as it can run a program recording the code of the method provided by the embodiments of the present application to communicate according to the method provided by the embodiments of the present application, for example, the execution entity of the method provided by the embodiments of the present application can be a terminal device or a network device, or a functional module in the terminal device or the network device that can call and execute the program.

[0139] In some embodiments, different network devices have different coverage ranges, and a terminal may switch from staying under one network device to another network device. For example, in satellite communication, multi-orbit satellites such as low Earth orbit (LEO) satellites, medium Earth orbit (MEO) satellites, and geostationary Earth orbit (GEO) satellites can provide different coverage ranges. Thus, by leveraging the different coverage and delay characteristics of different orbit satellites, the terminal can flexibly switch between satellites in different orbits, which can ensure service continuity and match the required quality of service (QoS) requirements, thereby effectively improving the reliability and availability of communication and meeting diverse service requirements globally.

[0140] When the terminal switches between two network devices, there are multiple factors such as a long signal propagation distance (such as the propagation delay of high-orbit satellites), signal processing time (demodulation, readjustment, etc.), multi-hop transmission (the signal needs to pass through multiple nodes), user equipment response time, and environmental factors (such as weather interference), which result in a large transmission delay.

[0141] Based on this, the embodiments of the present application provide a communication method, apparatus, terminal, and network device, which can reduce the delay caused by the terminal switching and transmitting between different network devices.

[0142] Figure 2 It is a schematic flowchart of a communication method shown in an embodiment of the present application. As Figure 2 shown, the communication method may include steps S201 to S205. The following will be described in detail Figure 2Each step in

[0143] S201. The terminal sends a second message to the first network device.

[0144] In some embodiments, the terminal camps on the first network device.

[0145] In some embodiments, the terminal accesses the first network device.

[0146] In some embodiments, the terminal camps in the network where the first network device is located.

[0147] In some embodiments, the terminal completes registration with the core network corresponding to the first network device at the first network device.

[0148] In some embodiments, the first network device receives the second message sent by the terminal.

[0149] In some embodiments, the second message includes at least one of the location information of the terminal, the preset network device information, or the service type information.

[0150] In some embodiments, the preset network device information can be used to indicate the type of network device that the terminal tends to access. Subsequently, the first network device can determine the second network device according to the preset network device information. For example, if the preset network device information is used to indicate a low-earth orbit type satellite, the second network device can be a low-earth orbit satellite, and the terminal can switch to access the second network device.

[0151] The service type information is used to indicate the type of service that the terminal needs to process. The second network device can be determined according to the service type information, and the terminal can switch to access the second network device.

[0152] The location information of the terminal can be used to determine a second network device that is closer to the specific terminal or can provide better quality service to the terminal, and the terminal can switch to access the second network device.

[0153] In some embodiments, the second message is one of the following: a Radio Resource Control (RRC) connection establishment request message, an RRC reestablishment request message, a handover request message, or a redirect request message.

[0154] For different second messages, the information carried by the second message can be the same or different.

[0155] For example, in one embodiment, the second message is an RRC connection establishment request message, and the second message includes the location information of the terminal and the preset network device information.

[0156] For another example, in one embodiment, the second message is an RRC connection establishment request message, and the second message includes the location information of the terminal and the service type information.

[0157] For example, in one embodiment, the second message is an RRC reestablishment request message, and the second message includes the location information of the terminal and the preset network device information.

[0158] For another example, in one embodiment, the second message is an RRC reestablishment request message, and the second message includes the location information of the terminal and the service type information.

[0159] For example, in one embodiment, the second message is a handover request message, and the second message includes the location information of the terminal and the preset network device information.

[0160] For another example, in one embodiment, the second message is a handover request message, and the second message includes the location information of the terminal and the service type information.

[0161] For another example, in one embodiment, the second message is a handover request message, and the second message includes the preset network device information of the terminal and the service type information.

[0162] For example, in one embodiment, the second message is a redirection request message, and the second message includes the service type information.

[0163] S202. The first network device sends a terminal access request message to the second network device.

[0164] In some embodiments, when the first network device receives the second message and determines through the second message that the terminal needs to be redirected to the second network device, at this time, the first network device sends a terminal access request message to the second network device.

[0165] It can be understood that in some embodiments, the first network device can determine the second network device according to one or more of the location information of the terminal, the preset network device information, or the service type information.

[0166] For example, in some embodiments, the first network device determines whether the terminal needs to be handed over according to the service type information, and then determines the second network device according to the location information or the service type information of the terminal.

[0167] In some embodiments, the location information of the terminal may not be carried in the second message, and the first network device can store the location information of the terminal when the terminal accesses. At this time, the second network device can be determined according to the location information of the terminal stored in the first network device.

[0168] In another embodiment, the location information of the terminal may not be carried in the second message. After the first network device determines that the terminal needs to switch to another network device, it may instruct the terminal to report the information of the terminal. At this time, the second network device may be determined according to the location information of the terminal.

[0169] In other embodiments, the first network device may also determine whether the terminal needs to switch according to the load of the first network device. For example, when the load of the first network device exceeds a certain value, at this time, the first network device determines that the terminal needs to perform a handover, and determines the second network device according to one or more of the location information of the terminal, the preset network device information, or the service type information.

[0170] In some embodiments, the first network device and the second network device are satellites, and the orbital altitude of the first network device is different from the orbital altitude of the second network device.

[0171] In some embodiments, the orbital altitude of the first network device is greater than the orbital altitude of the second network device.

[0172] In some embodiments, the orbital altitude of the first network device is less than the orbital altitude of the second network device.

[0173] In some embodiments, the terminal access request message is used to indicate that the terminal requests to access the second network device.

[0174] In some embodiments, the terminal access request may include a temporary identifier of the terminal. This temporary identifier may be carried in the temporary CRNTI or CRNTI of the first network device, and the terminal interacts with the first network device according to this temporary identifier of the terminal.

[0175] In some embodiments, the terminal access request may include the location information of the terminal.

[0176] In some embodiments, the terminal access request may include a Temporary Mobile Subscriber Identity (5G-TMSI).

[0177] In some embodiments, the terminal access request message includes one or more of a temporary identifier of the terminal, the location information of the terminal, or a temporary mobile subscriber identity.

[0178] S203. The second network device sends a terminal access request response message to the first network device.

[0179] In some embodiments, the second network device receives the terminal access request message sent by the first network device.

[0180] In some embodiments, the first network device receives the terminal response message.

[0181] In some embodiments, the second network device determines whether to allow the terminal to access the second network device according to the load status, access policy, etc. of the second network device.

[0182] In some embodiments, when the second network device determines to allow the terminal to access, the second network device sends a terminal access request response message to the first network device.

[0183] In some embodiments, when the second network device determines not to allow the terminal to access, the second network device sends a reject terminal access request response message to the first network device, indicating to the first network device that the second network device does not allow the terminal to access.

[0184] In some embodiments, the terminal access request response message includes a first temporary terminal identifier of the terminal.

[0185] The first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is the temporary identifier re - assigned by the second network device to the terminal.

[0186] The terminal can subsequently interact with the second network device according to the first temporary terminal identifier.

[0187] In some embodiments, if the temporary identifier assigned by the first network device to the terminal is different from the temporary identifier already assigned by the second network device, the first temporary terminal identifier can be the temporary identifier assigned by the first network device to the terminal.

[0188] In some embodiments, if the temporary identifier assigned by the first network device to the terminal is the same as the temporary identifier already assigned by the second network device, the first temporary terminal identifier can be the temporary identifier re - assigned by the second network device to the terminal.

[0189] In some embodiments, the terminal access request response message includes an estimated timing advance (TA) of the second network device, and the estimated timing advance is obtained by the second network device according to the location information of the terminal.

[0190] The estimated timing advance is the initial estimated timing advance for the subsequent terminal to transmit in the second network device, and the terminal can use the estimated timing advance for message transmission when sending a message to the second network.

[0191] In some embodiments, the second network device can determine the estimated timing advance according to artificial intelligence or big data statistics. For example, the second network device determines the TA with a low bit error rate used by other terminals at positions close to the position corresponding to the location information of the terminal as the estimated timing advance of the terminal.

[0192] In some embodiments, the terminal access request response message may include the ephemeris information of the second network device. This ephemeris information can be used by the terminal to determine the estimated time advance and can also be used by the terminal to quickly search for and determine the second network device and quickly access the second network device.

[0193] In some embodiments, the terminal access request response message may include the estimated time advance of the second network device and the ephemeris information of the second network device.

[0194] In some embodiments, the terminal access request response message may include the frequency point information of the second network device. This frequency point information may be the Absolute Radio Frequency Channel Number (ARFCN) of the second network device. The frequency point information of the second network device is used to indicate the frequency points currently supported by the network device, facilitating the terminal to quickly access the second network device based on this frequency point information.

[0195] In some embodiments, the terminal access request response message may include Physical Uplink Shared Channel (PUSCH) configuration information. This PUSCH configuration information is the PUSCH configuration information for transmitting the first message, and the first message is the message sent after the terminal sends the first preamble to the second network device.

[0196] In some embodiments, the PUSCH configuration information may include the RV (Redundancy Version) of the PUSCH, the modulation and coding scheme.

[0197] Based on this PUSCH configuration information, it can be determined how the terminal transmits the first message on the PUSCH.

[0198] In some embodiments, the terminal access request response message may include the subcarrier spacing (SCS) information of the second network device. This subcarrier spacing information may include the time-frequency resource granularity that the second network device can support, such as 15 kHz (kilohertz), 30 kHz, 60 kHz, etc. Through this subcarrier spacing information, low-latency information transmission between the terminal and the second network device is achieved.

[0199] It can be understood that when the terminal cannot determine the subcarrier spacing information of the second network device, the UE attempts different subcarrier spacings at each synchronization raster position for blind search until it finds a valid Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS), obtains the identifier of the second network device, and thus decodes the Physical Broadcast Channel (PBCH) and System Information Block Type 1 (SIB1) of the second network device.

[0200] In some embodiments, the terminal access request response message may include preamble sequence number information (redirectPreamble Index), which is used by the terminal to determine the first preamble transmitted to the second network device.

[0201] In some embodiments, the terminal access request response message may include preamble configuration information, which is the configuration information of the preamble used between the terminal and the second network device. The preamble configuration information is used to indicate at least one preamble and at least one random access occasion. The first preamble is one of the at least one preambles, and the transmission time of the first preamble is one of the at least one Random Access Occasions.

[0202] In some embodiments, the first preamble can be determined from at least one preamble according to the preamble sequence number information. The first preamble is the preamble transmitted by the terminal to the network device.

[0203] In some embodiments, the preamble configuration information can be the same as the random access configuration, or the preamble configuration information can be different from the random access configuration, or the preamble configuration information can be a part of the random access configuration.

[0204] In some embodiments, the terminal access request response message may include the SIB1 of the second network device.

[0205] In some embodiments, the SIB1 of the second network device may include preamble configuration information.

[0206] In some embodiments, the SIB is the Remaining Minimum SI (RMSI), that is, the remaining minimum system message except for the MIB.

[0207] In some embodiments, the terminal access request response message may include the system message of the second network device.

[0208] In some embodiments, the system message of the second network device includes the Master Information Block (MIB) and SIB1 of the second network device.

[0209] In some embodiments, the terminal access request response message may include wireless configuration information configured by the second network device for the terminal, and the wireless configuration information may include Radio Bearer Config (radio bearer configuration) information and CellGroupConfig (cell group configuration) information.

[0210] In some embodiments, the wireless configuration information is used to configure the communication resources and behaviors between the terminal and the second network device.

[0211] In some embodiments, the terminal access request response message includes an estimated time advance or ephemeris information of the second network device.

[0212] In some embodiments, the terminal access request response message includes the system message of the second network device, the wireless configuration information configured by the second network device for the terminal, the frequency point information of the second network device, and the first temporary terminal identifier of the terminal. The first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or at least one of the temporary identifiers re-assigned by the second network device to the terminal.

[0213] In some embodiments, the terminal access request response message includes at least one of the PUSCH configuration information for transmitting the first message, the subcarrier spacing information of the second network device, or the preamble sequence number information.

[0214] S204. The first network device sends a third message to the terminal.

[0215] In some embodiments, the first network device sends a third message to the terminal after receiving the access response message.

[0216] In some embodiments, the third message is the same as the information included in the access response message.

[0217] In some embodiments, the first network device sends a third message to the terminal according to the information included in the access response message.

[0218] In some embodiments, the third message includes information for the terminal to determine the estimated time advance of the second network device.

[0219] In some embodiments, the third message includes the estimated time advance of the second network device, that is, the information for the terminal to determine the estimated time advance of the second network device includes the estimated time advance.

[0220] In some embodiments, the third message may include the ephemeris information of the second network device, and this ephemeris information can be used by the terminal to determine the estimated time advance. That is, the information for the terminal to determine the estimated time advance of the second network device includes the ephemeris information of the second network device, and this ephemeris information of the second network device can also be used by the terminal to quickly search for and determine the second network device and quickly access the second network device.

[0221] In some embodiments, the terminal access request response message may include the estimated time advance of the second network device and the ephemeris information of the second network device.

[0222] In some embodiments, the third message may include the frequency point information of the second network device.

[0223] In some embodiments, the third message may include PUSCH configuration information.

[0224] In some embodiments, the third message may include the subcarrier spacing information of the second network device.

[0225] In some embodiments, the third message may include preamble sequence number information (redirect PreambleIndex), and this preamble sequence number information is used by the terminal to determine the first preamble transmitted to the second network device.

[0226] In some embodiments, the third message may include preamble configuration information, and this preamble configuration information is the configuration information of the preamble used between the terminal and the second network device. The preamble configuration information is used to indicate at least one preamble and at least one random access occasion. The first preamble is one of the at least one preambles, and the first transmission time of the first preamble is one of the at least one random access occasions.

[0227] In some embodiments, the third message may include SIB1 of the second network device.

[0228] In some embodiments, SIB1 of the second network device may include preamble configuration information.

[0229] In some embodiments, the third message of the terminal may include the system message of the second network device.

[0230] In some embodiments, the system message of the second network device includes the MIB and SIB1 of the second network device.

[0231] In some embodiments, sending the system message of the second network device to the terminal through the terminal access request response message and the third message can accelerate the access process of the terminal to the second network device.

[0232] In some embodiments, the third message may include wireless configuration information configured by the second network device for the terminal.

[0233] In some embodiments, the third message includes an estimated time advance or ephemeris information of the second network device.

[0234] In some embodiments, the third message includes system messages of the second network device, wireless configuration information configured by the second network device for the terminal, frequency point information of the second network device, and a first temporary terminal identifier of the terminal, where the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is a temporary identifier re-assigned by the second network device to the terminal, at least one of them.

[0235] In some embodiments, the third message includes at least one of PUSCH configuration information for transmitting the first message, subcarrier spacing information of the second network device, or preamble sequence number information.

[0236] It can be understood that for the specific description of the information included in the above third message, reference can be made to the specific description of the information included in the terminal access request response message, which will not be elaborated here.

[0237] S205. The terminal sends a first preamble and a first message to the second network device.

[0238] In some embodiments, the terminal receives the third message and determines the first preamble according to the third message.

[0239] In some embodiments, the terminal determines the first preamble according to preamble configuration information.

[0240] In some embodiments, the terminal determines the first preamble according to preamble sequence number information.

[0241] In some embodiments, the terminal transmits the first preamble and the first message according to at least one of subcarrier spacing information of the second network device, PUSCH configuration information, wireless configuration information, and frequency point information of the second network device.

[0242] In some embodiments, the terminal transmits the first message on the PUSCH according to the PUSCH configuration information for transmitting the first message.

[0243] In some embodiments, before the terminal sends the first preamble and the first message to the second network device, the terminal may also receive system messages broadcast by the second network device, and determine preamble configuration information through the system messages broadcast by the second network device.

[0244] That is, in some embodiments, the terminal may determine the preamble configuration information through the system message included in the third message; the terminal may also directly obtain the preamble configuration information through the third message; the terminal may also receive the system message broadcast by the second network device to determine the preamble configuration information.

[0245] In some embodiments, the terminal determines the first transmission time for sending the first preamble according to the random access opportunity.

[0246] In some embodiments, the terminal determines the second transmission time of the first message according to the PUSCH configuration information.

[0247] In some embodiments, the terminal sends the first preamble and the first message to the second network device according to the estimated time advance of the second network device.

[0248] In some embodiments, the third message includes the estimated time advance. The terminal sends the first preamble and the first message to the second network device according to the estimated time advance of the second network device.

[0249] In some embodiments, the third message includes the ephemeris information of the second network device. The terminal determines the estimated time advance of the second network device based on the ephemeris information of the second network device, and then the terminal sends the first preamble and the first message to the second network device according to the estimated time advance of the second network device.

[0250] In some embodiments, the terminal advances the estimated time advance at the first transmission time and sends the first preamble to the second network device; and advances the estimated time advance at the second transmission time and sends the first message to the second network device.

[0251] In some embodiments, the terminal sends the first message to the second network device on the physical uplink shared channel PUSCH corresponding to the first preamble.

[0252] In some embodiments, the second transmission time is separated from the first transmission time by a first preset time.

[0253] In some embodiments, the second transmission time is separated from the first transmission time by a preset number of symbols on the PUSCH, and the length corresponding to the preset number of symbols is the first preset time.

[0254] In some embodiments, the first preset time is predefined by the terminal, that is, it does not need to be indicated by signaling.

[0255] In some embodiments, the first preset time is sent by the first network device, and the first preset time may also be sent by the second network device to the terminal through the first network device. For example, the second network device sends the first preset time to the first network device, and the first network device sends the first preset time sent by the second network device to the terminal.

[0256] In some embodiments, the first network device may configure the interval between the first transmission time and the second transmission time, that is, the first preset time.

[0257] In some embodiments, the first preset time is carried in the third message.

[0258] In some embodiments, the first transmission time is earlier than the second transmission time.

[0259] In some embodiments, by setting the interval between the second transmission time and the first transmission time as the first preset time, it is convenient for the second network device to receive the first preamble first, so that the position of the PUSCH reception window can be adjusted according to the timing offset information of the first preamble, realizing accurate PUSCH synchronization and accurate reception of the first message.

[0260] In some embodiments, the timing offset information is used to indicate the time offset between the actual reception time window of the first preamble and the preset reception time window of the first preamble.

[0261] In some embodiments, the second network device receives the first preamble and can determine the actual reception time window of the first preamble.

[0262] In some embodiments, the terminal sends the first preamble to the second network device, and there is a corresponding preset reception time window for the first preamble.

[0263] In some embodiments, the timing offset information can be determined according to the preset reception time window of the first preamble and the actual reception time window of the first preamble. Thus, according to the timing offset information, the time offset between the preset reception time window of the first message and the actual reception time window of the first message can be determined. That is, the timing offset information can also be regarded as the time offset between the preset reception time window of the first message and the actual reception time window of the first message. Therefore, according to the preset reception time window of the first message and the timing offset information, the actual reception time window of the first message is determined, and the first message is received within the actual reception time window of the first message.

[0264] In some embodiments, the first message is one of the following: RRC connection setup complete message, RRC reestablishment complete message, handover complete message, RRC reconfiguration complete message, or redirect complete message.

[0265] In some embodiments, when the second network device receives the first message, it identifies that the terminal has accessed the second network device, and subsequent services can be completed through interaction with the second network device.

[0266] In some embodiments, after the terminal accesses the second network device, it can receive the first timing advance sent by the second network device, and subsequent information interaction with the second network device is performed through the first timing advance.

[0267] In some embodiments, the second network device receives the first message and sends the first timing advance to the terminal, thereby achieving precise synchronization through the first timing advance.

[0268] In some embodiments, the first timing advance can be carried in the Physical Downlink Control Channel (PDCCH) message or Physical Downlink Shared Channel (PDSCH) message of the second network device, or carried in the Timing Advance Command MAC CE (MAC control unit of the timing advance command) message of the PDSCH sent by the second network device, and the first timing advance instructs the terminal to perform uplink synchronization.

[0269] In the embodiments of the present application, before the terminal switches from the first network device to the second network device, it obtains the estimated timing advance of the second network device. The terminal can perform uplink pre-synchronization with the second network device through the estimated timing advance. Thus, the terminal sends the first preamble and the first message to the second network device through the estimated timing advance of the second network device, so that the second network device can accurately receive the first message and accelerate the access process of the terminal to the second network device.

[0270] In one embodiment, the terminal first sends the first preamble before sending the first message. The second network device can obtain the timing offset information according to the first preamble, thereby adjusting the position of the first message reception window through the timing offset information, achieving precise synchronization, and further improving the success rate of receiving the first message.

[0271] After sending the first message, the terminal also receives the first timing advance of the second network device, so as to achieve accurate uplink synchronization on the second network device after accessing the second network device.

[0272] It can be understood that in some embodiments, Figure 2 Steps S201 to S204 in are optional. The terminal can obtain the estimated timing advance of the second network device through other means, and send the first preamble and the first message to the second network device according to the estimated timing advance.

[0273] Figure 3 FIG. is a schematic flowchart of a communication method shown in another embodiment of the present application. It should be noted that the communication method in this embodiment is executed by the terminal. The terminal can be implemented by software and / or hardware.

[0274] Such as Figure 3 shown, the communication method may include steps S301 to S302. The following details Figure 3 each step in.

[0275] S301. Advance the estimated timing advance of the second network device at the first transmission time, and send the first preamble to the second network device.

[0276] In some embodiments, the terminal camps on the first network device.

[0277] In some embodiments, the terminal accesses the first network device.

[0278] In some embodiments, the terminal camps in the network where the first network device is located.

[0279] In some embodiments, the terminal completes registration with the core network corresponding to the first network device on the first network device.

[0280] In some embodiments, the terminal sends the first preamble and the first message to the second network device according to the estimated timing advance.

[0281] In some embodiments, the terminal performs uplink synchronization with the second network device according to the estimated timing advance.

[0282] In some embodiments, the terminal first sends the first preamble to the second network device, and then sends the first message to the second network device, so that the second network device can adjust the reception window of the first message according to the first preamble and accurately receive the first message.

[0283] In some embodiments, the estimated timing advance can be sent by the second network device to the terminal, or can be calculated by the terminal according to the ephemeris information of the second network device.

[0284] In some embodiments, the second network device sends the estimated time advance to the terminal via the first network device.

[0285] S302. Estimate the time advance at the second transmission time, and send a first message to the second network device on a physical uplink shared channel (PUSCH) corresponding to the first preamble.

[0286] It can be understood that the related implementation manners of the terminal sending the first preamble and the first message to the second network device may refer to step S205 and its related implementation manners, which will not be elaborated here.

[0287] In an implementable manner, the terminal estimates the time advance at the first transmission time and sends the first preamble to the second network device; the terminal estimates the time advance at the second transmission time and sends the first message to the second network device.

[0288] In some embodiments, the first transmission time is the transmission time of the first preamble, and the first transmission time may be a pre-set time, or a time negotiated between the second network device and the terminal, such as a certain time in the random access opportunity of the preamble.

[0289] In some embodiments, the second transmission time is the transmission time of the first message, and the second transmission time may be a pre-set time, or a time negotiated between the second network device and the terminal.

[0290] In some embodiments, the second transmission time is separated from the first transmission time by a first preset time.

[0291] In an implementable manner, the first preset time is predefined, or the first preset time is sent by the first network device.

[0292] It can be understood that the related descriptions of the first transmission time and the second transmission time above may refer to the descriptions of the first transmission time and the second transmission time in step S205, which will not be elaborated here.

[0293] In an implementable manner, the orbital altitude of the first network device is different from that of the second network device.

[0294] The orbital altitude of the first network device is different from that of the second network device, corresponding to the coverage ranges of the first network device and the second network device being different, and the terminal can perform a quick handover between the first network device and the second network device.

[0295] When the terminal camps on the first network device, due to service requirements, or the first network device being overloaded, or other relevant reasons, the terminal needs to perform a handover. Thus, it can send a first preamble and a first message to the second network device by determining the estimated advance of the second network device, so as to quickly hand over to the second network device.

[0296] In an implementable manner, the terminal sends a first preamble to the second network device according to preamble configuration information, where the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity. The first preamble is one of the at least one preambles, and the first transmission time of the first preamble is one of the at least one random access opportunities.

[0297] In some embodiments, the terminal can receive the preamble configuration information and determine the first preamble and the first transmission time of the first preamble through the preamble configuration information. Thus, the first preamble is sent through the preamble configuration information.

[0298] In some embodiments, the preamble configuration information can be sent from the second network device to the terminal.

[0299] In some embodiments, the second network device can broadcast a system message, and the system message includes the preamble configuration information. Thus, the terminal obtains the preamble configuration information according to the broadcast system message.

[0300] In some embodiments, the second network device can send the preamble configuration information to the terminal through the first network device. For example, Figure 2 as described in the relevant embodiments, the second network device sends a terminal access request response message to the first network device, and the terminal access request response message includes the preamble configuration information. The first network device receives the terminal access request response message and sends a third message to the terminal, and the third message includes the preamble configuration information. Thus, the terminal obtains the preamble configuration information according to the third message.

[0301] In some embodiments, the second network device can send the preamble configuration information to the terminal through the first network device. For example, Figure 2 as described in the relevant embodiments, the second network device sends a terminal access request response message to the first network device, and the terminal access request response message includes the system message of the second network device. The system message of the second network device includes the preamble configuration information. The first network device receives the terminal access request response message and sends a third message to the terminal, and the third message includes the system message of the second network device. The system message of the second network device includes the preamble configuration information. Thus, the terminal obtains the preamble configuration information according to the system message in the third message.

[0302] It can be understood that for the relevant description of the preamble configuration information, reference can be made to the relevant description methods of the preamble configuration information in step S203, step S204, and step S205, which will not be elaborated here.

[0303] In an implementable manner, the terminal sends a first message to a second network device on a physical uplink shared channel PUSCH corresponding to a first preamble.

[0304] In some embodiments, the terminal may receive PUSCH configuration information sent by the second network device and transmit the first message based on this PUSCH configuration information.

[0305] It can be understood that since the first transmission time and the second transmission time are separated by a first preset time, therefore, the first preamble is sent first on the PUSCH, and after a first preset time interval, the first message is sent on the PUSCH.

[0306] In an implementable manner, the first message is one of the following: a radio resource control RRC connection establishment completion message, an RRC reconstruction completion message, a handover completion message, an RRC reconfiguration completion message, or a redirection completion message.

[0307] In some embodiments, the terminal indicates to the second network device that the terminal accesses the second network device by sending the first message.

[0308] In an implementable manner, after sending the first message, the terminal may receive a first timing advance from the second network device.

[0309] In some embodiments, the second network device receives the first message and determines that the terminal accesses the second network device. At this time, the second network device may send a first timing advance to the terminal, and subsequently, the terminal may perform precise uplink synchronization with the second network device through this first timing advance.

[0310] In an implementable manner, before sending the first preamble and the first message to the second network device according to the estimated timing advance of the second network device, the terminal sends a second message to a first network device; the terminal receives a third message from the first network device, and the third message includes an estimated timing advance.

[0311] When the terminal has services, it may send a second message to the resident first network device to inform the first network device that the terminal requests to access for services.

[0312] The first network device may respond to the second message and determine that the terminal can access the second network device, and thus send the estimated timing advance to the terminal through the third message. In this way, the terminal can obtain the estimated timing advance of the second network device.

[0313] It can be understood that the relevant description method of the second message can refer to the relevant description method of the second message in step S201, which will not be elaborated here.

[0314] In one implementable manner, the third message includes wireless configuration information configured by the second network device for the terminal.

[0315] In some embodiments, the wireless configuration information is used to configure communication resources and behaviors between the terminal and the second network device.

[0316] It can be understood that the specific description of the wireless configuration information can refer to the relevant description of the wireless configuration information in step S203 and step S204, which will not be elaborated here.

[0317] In one implementable manner, the third message further includes frequency point information of the second network device.

[0318] In some embodiments, the frequency point information of the second network device is used to indicate the frequency points currently supported by the network device, facilitating the terminal to quickly access the second network device according to the frequency point information.

[0319] It can be understood that the specific description of the frequency point information can refer to the relevant description of the frequency point information in step S203 and step S204, which will not be elaborated here.

[0320] In one implementable manner, the third message further includes a first temporary terminal identifier of the terminal, and the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is a temporary identifier re - assigned by the second network device to the terminal.

[0321] In some embodiments, the terminal can subsequently interact with the second network device according to the first temporary terminal identifier.

[0322] It can be understood that the specific description of the first temporary terminal identifier can refer to the relevant description of the first temporary terminal identifier in step S203 and step S204, which will not be elaborated here.

[0323] In one implementable manner, the preamble configuration information is obtained by one of the following methods: receiving a system message broadcast by the second network device, where the system message includes the preamble configuration information; the third message further includes a system message of the second network device, where the system message includes the preamble configuration information; the third message further includes the preamble configuration information.

[0324] In one implementable manner, the third message further includes at least one of the following parameters: ephemeris information of the second network device, PUSCH configuration information for transmitting the first message, sub - carrier spacing information of the second network device, or preamble sequence number information, where the preamble sequence number information is used to indicate the first preamble.

[0325] It can be understood that for the specific description of the third message, reference can be made to the relevant description of the third message in step S204 and step S205, which will not be elaborated here.

[0326] In an implementable manner, before sending the first preamble and the first message to the second network device according to the estimated time advance of the second network device, the terminal sends a second message to the first network device; receives a third message from the first network device, where the third message includes the ephemeris information of the second network device; and determines the estimated time advance of the second network device based on the ephemeris information of the second network device.

[0327] In some embodiments, the third message includes ephemeris information. At this time, the terminal can directly calculate the estimated time advance of the second network device according to the ephemeris information.

[0328] In an implementable manner, when the third message includes ephemeris information, the terminal obtains the preamble configuration information in one of the following ways: receives the system message broadcast by the second network device, where the system message includes the preamble configuration information; the third message further includes the system message of the second network device, where the system message includes the preamble configuration information; the third message further includes the preamble configuration information.

[0329] In an implementable manner, when the third message includes ephemeris information, the third message further includes at least one of the following parameters: the wireless configuration information configured by the second network device for the terminal, the frequency point information of the second network device, the first temporary terminal identifier of the terminal, where the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is the temporary identifier re-assigned by the second network device to the terminal.

[0330] In an implementable manner, when the third message includes ephemeris information, the third message further includes at least one of the following parameters: the PUSCH configuration information for transmitting the first message, the subcarrier spacing information of the second network device, or the preamble sequence number information, where the preamble sequence number information is used to indicate the first preamble.

[0331] In an implementable manner, the third message is one of the following: an RRC connection establishment message, an RRC connection re-establishment message, a handover command message, or a redirection command message.

[0332] It can be understood that when the third message includes ephemeris information, for the specific description of the third message, reference can be made to the relevant description of the third message in step S204 and step S205, which will not be elaborated here.

[0333] In an implementable manner, the second message includes at least one of the following parameters: the location information of the terminal, the preset network device information, or the service type information.

[0334] In some embodiments, the second message of the terminal may include at least one of the location information of the terminal, preset network device information, or service type information. Thus, the first network device may determine whether the terminal needs to switch to the second network device according to at least one of the location information of the terminal, preset network device information, or service type information.

[0335] In some embodiments, the first network device receives the second message of the terminal, and then determines that the terminal needs to switch to the second network device. The first network device may send a terminal access request message to the second network device and receive a terminal access request response message fed back by the second network device, and thus determine the information in the third message according to the information in the terminal access response request message.

[0336] In one implementable manner, the second message is one of the following: an RRC connection establishment request message, an RRC reconstruction request message, a handover request message, or a redirection request message.

[0337] It can be understood that for the specific description of the second message, reference may be made to the relevant description of the second message in step S201 and step S202, which will not be elaborated here.

[0338] It can be understood that for the implementation manner in which the first network device determines whether the terminal accesses the second network device according to the second message, reference may be made to the relevant description in step S201 and step S202, which will not be elaborated here.

[0339] Figure 4 FIG. is a schematic flowchart of a communication method shown in another embodiment of the present application. It should be noted that, in this embodiment, the communication method is executed by the first network device. The first network device may be implemented by software and / or hardware.

[0340] As Figure 4 shown, the communication method may include steps S401 to S403. The following will elaborate in detail Figure 4 each of the steps.

[0341] S401. Receive a first preamble from the terminal; the terminal camps on the first network device, and the first preamble is sent at a first transmission time advanced by the estimated time advance amount of the second network device.

[0342] In some embodiments, the terminal camps on the first network device.

[0343] In some embodiments, the terminal accesses the first network device.

[0344] In some embodiments, the terminal camps on the network where the first network device is located.

[0345] In some embodiments, the terminal sends a first preamble to a second network device according to a predicted time advance.

[0346] S402. Determine timing offset information according to the actual reception time window of the first preamble, where the timing offset information is used to indicate the time offset between the actual reception time window of the first preamble and the preset reception time window of the first preamble.

[0347] In one implementable manner, the second network device receives the first preamble first.

[0348] The second network device determines timing offset information according to the actual reception time window of the first preamble, where the timing offset information is used to indicate the time offset between the actual reception time window of the first preamble and the preset reception time window of the first preamble; and receives a first message on a physical uplink shared channel PUSCH corresponding to the first preamble according to the timing offset information.

[0349] S403. Receive a first message on a physical uplink shared channel PUSCH corresponding to the first preamble according to the timing offset information.

[0350] In one implementable manner, the terminal sends a first message on a physical uplink shared channel PUSCH corresponding to the first preamble, and the second network device receives the first message sent by the terminal on the physical uplink shared channel PUSCH corresponding to the first preamble.

[0351] In some embodiments, the timing offset information can be determined according to the preset reception time window of the first preamble and the actual reception time window of the first preamble. Thus, according to the timing offset information, the time offset between the preset reception time window of the first message and the actual reception time window of the first message can be determined, that is, the timing offset information can also be regarded as the time offset between the preset reception time window of the first message and the actual reception time window of the first message. Therefore, according to the preset reception time window of the first message and the timing offset information, the actual reception time window of the first message is determined, and the first message is received at the actual reception time window of the first message.

[0352] It can be understood that the relevant implementable manners for the second network device to receive the first message according to the first preamble can refer to the relevant implementable manners for the first preamble and the first message in step S205, which will not be elaborated here.

[0353] In one implementable manner, the first preamble is sent with a predicted time advance at a first transmission time, the first message is sent with a predicted time advance at a second transmission time, and the second transmission time and the first transmission time on the PUSCH are separated by a first preset time.

[0354] In some embodiments, by setting the second transmission time to be separated from the first transmission time by a first preset time, it is convenient for the second network device to first receive the first preamble, so that the position of the PUSCH reception window can be adjusted according to the timing offset information of the first preamble, achieving accurate PUSCH synchronization and accurate reception of the first message.

[0355] In some embodiments, the terminal sends a first preamble and a first message to the second network device according to the estimated time advance.

[0356] In some embodiments, after receiving the first message, the second network device determines that the terminal has accessed the second network device.

[0357] It can be understood that the related implementation manners of the second network device receiving the first preamble and the first message sent by the terminal can refer to step S205, step S301 and their related implementation manners, which will not be elaborated here.

[0358] In one implementable manner, the orbital altitude of the first network device is different from that of the second network device.

[0359] In some embodiments, the orbital altitude of the first network device is different from that of the second network device, and the coverage range of the first network device is different from that of the second network device. The terminal can quickly switch between the first network device and the second network device, enabling the terminal to execute services more efficiently.

[0360] In one implementable manner, the first message is at least one of the following: RRC connection establishment complete message, RRC reconstruction complete message, handover complete message, RRC reconfiguration complete message, or redirection complete message.

[0361] In one implementable manner, before receiving the first preamble from the terminal, the method further includes: the second network device receives a terminal access request message from the first network device; the second network device sends a terminal access request response message to the first network device, and the terminal access request response message includes the estimated time advance of the second network device.

[0362] The estimated time advance of the second network device is obtained according to the position information of the terminal.

[0363] In one implementable manner, the terminal access request response message further includes a first temporary terminal identifier of the terminal, where the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is a temporary identifier re - assigned by the second network device to the terminal.

[0364] In some embodiments, the terminal access request message is used to indicate that the terminal needs to access a second network device. After the second network device determines that the terminal can be accessed, it feeds back the information required for the terminal to access the second network device, such as the estimated time advance, to the first network device through the terminal access request response message. The first network device sends the estimated time advance carried in the terminal access request response message to the terminal, such as sending the estimated time advance carried in the access request response message to the terminal through a third message. In this way, the terminal can determine the estimated time advance according to the information in the third message. Accordingly, the first preamble and the first message are sent to the second network device according to the estimated time advance of the second network device.

[0365] In one implementable manner, before receiving the first preamble from the terminal, the second network device receives the terminal access request message from the first network device; and sends the terminal access request response message to the first network device, where the terminal access request response message includes the ephemeris information of the second network device.

[0366] In one implementable manner, the terminal access request response message further includes a first temporary terminal identifier of the terminal, where the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is a temporary identifier re-assigned by the second network device to the terminal.

[0367] In some embodiments, the terminal access request message is used to indicate that the terminal needs to access a second network device. After the second network device determines that the terminal can be accessed, it feeds back the information required for the terminal to access the second network device, such as the ephemeris information of the second network device, to the first network device through the terminal access request response message. The first network device sends the ephemeris information of the second network device carried in the terminal access request response message to the terminal, such as sending the ephemeris information of the second network device carried in the access request response message to the terminal through a third message. In this way, the terminal can determine the ephemeris information of the second network device according to the information in the third message, and determine the estimated time advance according to the ephemeris information of the second network device. Accordingly, the first preamble and the first message are sent to the second network device according to the estimated time advance of the second network device.

[0368] In one implementable manner, the terminal access request response message further includes: the system message of the second network device; where the system message includes preamble configuration information, and the preamble configuration information is used to indicate at least one preamble and at least one random access occasion. The first preamble is one of the at least one preambles, and the first transmission time of the first preamble is one of the at least one random access occasions.

[0369] In one implementable manner, the terminal access request response message further includes preamble configuration information; wherein, the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity, the first preamble is one of the at least one preamble, and the first transmission time of the first preamble is one of the at least one random access opportunity.

[0370] The preamble configuration information can be sent by the first network device to the terminal, and the terminal can determine the first preamble and the first transmission time of the first preamble according to the preamble configuration information.

[0371] It can be understood that the relevant description of the preamble configuration information can refer to the relevant description of the preamble configuration information in step S203, step S204, and step S205, which will not be elaborated here.

[0372] In one implementable manner, the terminal access request response message further includes at least one of the following parameters: PUSCH configuration information for transmitting the first message, subcarrier spacing information of the second network device, wireless configuration information configured by the second network device for the terminal, frequency point information of the second network device, or preamble sequence number information, and the preamble sequence number information is used to indicate the first preamble.

[0373] In some embodiments, the terminal access request response message includes ephemeris information of the second network device or the estimated time advance of the second network device. In addition, the terminal access request response message further includes at least one of the following parameters: PUSCH configuration information for transmitting the first message, subcarrier spacing information of the second network device, wireless configuration information configured by the second network device for the terminal, frequency point information of the second network device, or preamble sequence number information.

[0374] It can be understood that the relevant description of the terminal access request response message can refer to the relevant description of the terminal access request response message in step S203, which will not be elaborated here.

[0375] In one implementable manner, after receiving the first preamble and the first message from the terminal, the second network device sends the first time advance to the terminal.

[0376] The terminal can achieve precise synchronization with the second network device through the first time advance.

[0377] Figure 5 It is a schematic flow diagram of a communication method shown in another embodiment of the present application. It should be noted that, in this embodiment, the communication method is executed by the first network device. The first network device can be implemented by software and / or hardware.

[0378] As Figure 5 shown, the communication method may include step S501. The following will be described in detailFigure 5 Each step in

[0379] S501. Send a third message to the terminal, where the third message includes information for the terminal to determine the estimated time advance of the second network device.

[0380] In some embodiments, the terminal camps on the first network device.

[0381] In some embodiments, the terminal accesses the first network device.

[0382] In some embodiments, the terminal camps in the network where the first network device is located.

[0383] In some embodiments, the information for the terminal to determine the estimated time advance of the second network device includes the estimated time advance of the second network device, and the first network device indicates the estimated time advance of the second network device to the terminal through the third message.

[0384] In some embodiments, the information for the terminal to determine the estimated time advance of the second network device includes the ephemeris information of the second network device, and the first network device indicates the estimated time advance of the second network device to the terminal through the third message. The terminal determines the estimated time advance of the second network device according to the third message, and sends a first preamble and a first message to the second network device according to the estimated time advance of the second network device.

[0385] In one implementable manner, the orbital altitude of the first network device is different from that of the second network device.

[0386] In some embodiments, the orbital altitude of the first network device is different from that of the second network device, and the coverage range of the first network device is different from that of the second network device. The terminal can perform a quick handover between the first network device and the second network device, so that the terminal can execute services more efficiently.

[0387] In one implementable manner, the third message includes the estimated time advance of the second network device for the terminal, that is, the information for the terminal to determine the estimated time advance of the second network device includes the estimated time advance of the second network device; wherein, the estimated time advance of the second network device is obtained according to the location information of the terminal.

[0388] In one implementable manner, the third message further includes a first temporary terminal identifier of the terminal, and the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is the temporary identifier re-assigned by the second network device to the terminal.

[0389] In some embodiments, the terminal and the second network device interact through the first temporary terminal identifier.

[0390] It is understandable that for the specific description of the first temporary terminal identifier, reference can be made to the relevant descriptions of the first temporary terminal identifier in step S203 and step S204, which will not be elaborated here.

[0391] In some embodiments, the third message includes an estimated time advance, so that the terminal can directly obtain the estimated time advance through the third message.

[0392] In one embodiment, the second network device calculates the estimated time advance based on the location information of the terminal and sends it to the terminal through the third message of the second network device.

[0393] In one implementable manner, the third message includes the ephemeris information of the second network device for the terminal, that is, the information used by the terminal to determine the estimated time advance of the second network device, the ephemeris information of the second network device.

[0394] In one implementable manner, the third message further includes the first temporary terminal identifier; wherein, the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is the temporary identifier re-assigned by the second network device to the terminal.

[0395] In some embodiments, the third message includes the ephemeris information of the second network device, and the terminal can calculate the estimated time advance based on the ephemeris information of the second network device.

[0396] In one implementable manner, the third message further includes the system message of the second network device; wherein, the system message includes preamble configuration information, and the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity.

[0397] In some embodiments, the system message of the second network device is carried by the third message, enabling the terminal to quickly receive the system message of the second network device for quick synchronization.

[0398] The system message of the second network device further includes preamble configuration information, whereby the first preamble sent by the terminal to the second network device is configured through the preamble configuration information.

[0399] In one implementable manner, the third message further includes preamble configuration information; wherein, the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity.

[0400] In some embodiments, the preamble configuration information is carried by the third message, whereby the first preamble sent by the terminal to the second network device is configured through the preamble configuration information.

[0401] In one implementable manner, the third message further includes at least one of the following parameters: the first temporary terminal identifier of the terminal, the wireless configuration information configured by the second network device for the terminal, the frequency point information of the second network device, the PUSCH configuration information for transmitting the first message, the subcarrier spacing information of the second network device, or the preamble sequence number information, where the preamble sequence number information is used to indicate the first preamble.

[0402] In some embodiments, the preamble sequence number information is used to indicate the first preamble, and the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is the temporary identifier re-assigned by the second network device to the terminal.

[0403] In one implementable manner, the third message is one of the following: an RRC connection establishment message, an RRC connection reconstruction message, a handover command message, or a redirection command message.

[0404] It can be understood that the relevant description of the third message can refer to the relevant description of the third message in step S204 and step S205, which will not be elaborated here.

[0405] In one implementable manner, before sending the third message to the terminal, the first network device receives a second message from the terminal; and after receiving the second message, sends a terminal access request message to the second network device.

[0406] In some embodiments, after sending the terminal access request message, the first network device receives a terminal access request response message from the second network device, and the terminal access request response message includes the estimated time advance of the second network device.

[0407] In one implementable manner, before sending the third message to the terminal, the first network device receives a second message from the terminal; the first network device sends a terminal access request message to the second network device; the first network device receives a terminal access request response message from the second network device, and the terminal access request response message includes the ephemeris information of the second network device.

[0408] In some embodiments, the terminal needs to access a network device for services, and the terminal camps on the first network device, thereby sending a second message to the first network device to indicate the need to access the network device.

[0409] In one implementable manner, the second message includes at least one of the following parameters: the location information of the terminal, the preset network device information, or the service type information.

[0410] The first network device can determine whether the terminal needs to switch to the second network device according to the second message. After determining that the terminal needs to switch to the second network device, the first network device sends a terminal access request message to the second network device, indicating that the terminal needs to access the second network device.

[0411] After the second network device determines that the terminal can access, it feeds back a terminal access request response message to the first network device. The first network device can determine a third message based on the information carried in the terminal access request response message, and thus send the information required for the terminal to access the second network device to the terminal, such as sending the estimated time advance or the ephemeris information of the second network device to the terminal.

[0412] In an implementable manner, the terminal access request response message further includes: a first temporary terminal identifier of the terminal, and a system message of the second network device; wherein, the system message includes preamble configuration information, and the preamble configuration information is used to indicate at least one preamble and at least one random access occasion. The first preamble is one of the at least one preamble, and the first transmission time of the first preamble is one of the at least one random access occasion.

[0413] In some embodiments, the preamble sequence number information is used to indicate the first preamble, and the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is the temporary identifier re-assigned by the second network device to the terminal.

[0414] In an implementable manner, the terminal access request response message further includes preamble configuration information; wherein, the preamble configuration information is used to indicate at least one preamble and at least one random access occasion. The first preamble is one of the at least one preamble, and the first transmission time of the first preamble is one of the at least one random access occasion.

[0415] It can be understood that the relevant description of the preamble configuration information can refer to the relevant description of the preamble configuration information in step S203, step S204, and step S205, and will not be elaborated here.

[0416] In an implementable manner, the second message is one of the following: an RRC connection establishment request message, an RRC reconstruction request message, a handover request message, or a redirection request message.

[0417] It can be understood that the relevant description manner of the second message can refer to the relevant description manner of the second message in step S201, and will not be elaborated here.

[0418] In an implementable manner, the terminal access request response message further includes at least one of the following parameters: wireless configuration information configured by the second network device for the terminal, frequency point information of the second network device, PUSCH configuration information for transmitting the first message, subcarrier spacing information of the second network device, or preamble sequence number information, and the preamble sequence number information is used to indicate the first preamble.

[0419] It can be understood that the relevant description of the terminal access request response message can refer to the relevant description of the terminal access request response message in step S203, which will not be elaborated here.

[0420] Figure 6 is a schematic block diagram of a communication device shown in an embodiment of the present application. As Figure 6 shown, the communication device 600 may include a sending module 601.

[0421] In one embodiment, the communication device 600 can be used to implement the operations corresponding to the terminal in the above embodiments. In some embodiments, the communication device 600 is a terminal, or a component configured in the terminal, such as a chip or a circuit.

[0422] The communication device 600 can implement Figures 2 to 5 the corresponding operations of the terminal in the embodiment of the communication method shown. The communication device 600 may include modules for executing Figures 2 to 5 the methods executed by the terminal in the embodiment of the communication method shown. And, each module in the communication device 600 and the above other operations and / or functions respectively are for implementing Figures 2 to 5 the corresponding processes in the embodiment of the communication method shown.

[0423] In some embodiments, the sending module 601 is used to advance the estimated time advance of the second network device by a first sending time, and send a first preamble to the second network device; the sending module 601 is further used to advance the estimated time advance at a second sending time, and send a first message to the second network device on a physical uplink shared channel PUSCH corresponding to the first preamble; wherein, the second sending time is separated from the first sending time by a first preset time

[0424] In some embodiments, the terminal camps on the first network device.

[0425] In an implementable manner, the sending module 601 is further used to send a first preamble to the second network device according to preamble configuration information, the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity, the first preamble is one of the at least one preamble, and the first sending time of the first preamble is one of the at least one random access opportunity.

[0426] In an implementable manner, the first preset time is predefined, or, the first preset time is sent by the first network device.

[0427] In an implementable manner, the first message is one of the following: a radio resource control RRC connection establishment complete message, an RRC reestablishment complete message, a handover complete message, an RRC reconfiguration complete message, or a redirection complete message.

[0428] In one implementable manner, the communication device 600 may further include a receiving module.

[0429] A sending module, further configured to send a second message to a first network device; a receiving module, configured to receive a third message from the first network device, where the third message includes an estimated timing advance.

[0430] In one implementable manner, the third message includes wireless configuration information configured by a second network device for a terminal.

[0431] In one implementable manner, the third message further includes frequency point information of the second network device.

[0432] In one implementable manner, the third message further includes a first temporary terminal identifier of the terminal, where the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is a temporary identifier re - assigned by the second network device to the terminal.

[0433] In one implementable manner, the preamble configuration information is obtained by one of the following methods: receiving a system message broadcast by the second network device, where the system message includes the preamble configuration information; the third message further includes a system message of the second network device, where the system message includes the preamble configuration information; the third message further includes the preamble configuration information.

[0434] In one implementable manner, the third message further includes at least one of the following parameters: ephemeris information of the second network device, PUSCH configuration information for transmitting the first message, sub - carrier spacing information of the second network device, or preamble sequence number information, where the preamble sequence number information is used to indicate a first preamble.

[0435] In one implementable manner, the receiving module is further configured to send a second message to the first network device; the receiving module is further configured to receive a third message from the first network device, where the third message includes ephemeris information of the second network device.

[0436] The communication device 600 may further include a processing module, configured to determine an estimated timing advance of the second network device based on the ephemeris information of the second network device.

[0437] In one implementable manner, the terminal obtains the preamble configuration information by one of the following methods: receiving a system message broadcast by the second network device, where the system message includes the preamble configuration information; the third message further includes a system message of the second network device, where the system message includes the preamble configuration information; the third message further includes the preamble configuration information.

[0438] In one implementable manner, the third message further includes at least one of the following parameters: the wireless configuration information configured by the second network device for the terminal, the frequency point information of the second network device, the first temporary terminal identifier of the terminal, and the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is the temporary identifier re-assigned by the second network device to the terminal.

[0439] In one implementable manner, the third message further includes at least one of the following parameters: the PUSCH configuration information for transmitting the first message, the subcarrier spacing information of the second network device, or the preamble sequence number information, and the preamble sequence number information is used to indicate the first preamble.

[0440] In one implementable manner, the second message includes at least one of the following parameters: the location information of the terminal, the preset network device information, or the service type information.

[0441] In one implementable manner, the second message is one of the following: an RRC connection establishment request message, an RRC re-establishment request message, a handover request message, or a redirection request message.

[0442] In one implementable manner, the third message is one of the following: an RRC connection establishment message, an RRC connection re-establishment message, a handover command message, or a redirection command message.

[0443] In one implementable manner, the receiving module is further configured to receive the first timing advance from the second network device.

[0444] In one implementable manner, the orbital altitude of the first network device is different from that of the second network device.

[0445] Figure 7 is a schematic block diagram of a communication device shown in an embodiment of the present application. As Figure 7 shown, the communication device 700 may include a receiving module 701 and a processing module 702.

[0446] In one embodiment, the communication device 700 can be used to implement the operations corresponding to the second network device in the above embodiments. In some embodiments, the communication device 700 is the second network device or a component configured in the second network device, such as a chip or a circuit.

[0447] The communication device 700 can implement Figures 2 to 5 the corresponding operations of the second network device in the embodiment of the communication method shown. The communication device 700 may include modules for executing Figures 2 to 5 the methods executed by the second network device in the embodiment of the communication method shown. And, each module in the communication device 700 and the above other operations and / or functions are respectively for implementing Figures 2 to 5The corresponding processes in the embodiments of the communication method shown.

[0448] In some embodiments, a receiving module 701 is configured to receive a first preamble from a terminal; the terminal camps on a first network device, and the first preamble is sent at a first transmission time advanced by a predicted time advance amount of a second network device; a processing module 702 is configured to determine timing offset information according to an actual reception time window of the first preamble, where the timing offset information is used to indicate a time offset amount between the actual reception time window of the first preamble and a preset reception time window of the first preamble; the receiving module 701 is further configured to receive a first message on a physical uplink shared channel PUSCH corresponding to the first preamble according to the timing offset information; the first message is sent at a second transmission time advanced by the predicted time advance amount, and a second transmission time and a first transmission time on the PUSCH are separated by a first preset time. In one implementable manner, the first message is at least one of the following: an RRC connection establishment completion message, an RRC reconstruction completion message, a handover completion message, an RRC reconfiguration completion message, or a redirection completion message.

[0449] In one implementable manner, the receiving module 701 is further configured to receive a terminal access request message from the first network device; the communication device 700 further includes a sending module, and the sending module is configured to send a terminal access request response message to the first network device, where the terminal access request response message includes the predicted time advance amount of the second network device; wherein, the predicted time advance amount of the second network device is obtained according to the location information of the terminal.

[0450] In one implementable manner, the receiving module 701 is further configured to receive a terminal access request message from the first network device; the sending module is further configured to send a terminal access request response message to the first network device, where the terminal access request response message includes ephemeris information of the second network device.

[0451] In one implementable manner, the terminal access request response message further includes: system information of the second network device; wherein, the system information includes preamble configuration information, and the preamble configuration information is used to indicate at least one preamble and at least one random access occasion, the first preamble is one of the at least one preamble, and the first transmission time of the first preamble is one of the at least one random access occasion.

[0452] In one implementable manner, the terminal access request response message further includes preamble configuration information; wherein, the preamble configuration information is used to indicate at least one preamble and at least one random access occasion, the first preamble is one of the at least one preamble, and the first transmission time of the first preamble is one of the at least one random access occasion.

[0453] In one implementable manner, the terminal access request response message further includes at least one of the following parameters: the first temporary terminal identifier of the terminal, the PUSCH configuration information for transmitting the first message, the subcarrier spacing information of the second network device, the radio configuration information configured by the second network device for the terminal, the frequency point information of the second network device, or the preamble sequence number information; wherein, the preamble sequence number information is used to indicate the first preamble, and the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is the temporary identifier re-assigned by the second network device to the terminal.

[0454] In one implementable manner, the sending module is further configured to send a first timing advance to the terminal.

[0455] In one implementable manner, the orbital altitude of the first network device is different from that of the second network device.

[0456] Figure 8 is a schematic block diagram of a communication device shown in an embodiment of the present application. As Figure 8 shown, the communication device 800 may include a sending module 801.

[0457] In one embodiment, the communication device 800 can be used to implement the operations corresponding to the first network device in the above embodiments. In some embodiments, the communication device 800 is the first network device, or a component configured in the first network device, such as a chip or a circuit.

[0458] The communication device 800 can implement Figures 2 to 5 the corresponding operations of the first network device in the embodiment of the communication method shown. The communication device 800 may include modules for executing Figures 2 to 5 the methods executed by the first network device in the embodiment of the communication method shown. And, each module in the communication device 800 and the above other operations and / or functions respectively are for implementing Figures 2 to 5 the corresponding processes in the embodiment of the communication method shown.

[0459] In some embodiments, the sending module 801 is configured to send a third message to the terminal. The third message includes information for the terminal to determine the estimated timing advance of the second network device. The information for the terminal to determine the estimated timing advance of the second network device includes at least one of the estimated timing advance of the second network device or the ephemeris information of the second network device;

[0460] The third message further includes at least one of the following parameters: the first temporary terminal identifier of the terminal, the wireless configuration information configured by the second network device for the terminal, the frequency point information of the second network device, the PUSCH configuration information for transmitting the first message, the subcarrier spacing information of the second network device, or the preamble sequence number information; wherein, the preamble sequence number information is used to indicate the first preamble, and the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is the temporary identifier re-assigned by the second network device to the terminal.

[0461] In one implementable manner, the third message further includes the system message of the second network device; wherein, the system message includes preamble configuration information, and the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity.

[0462] In one implementable manner, the third message further includes preamble configuration information; wherein, the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity.

[0463] In one implementable manner, the communication device 800 further includes a receiving module, configured to receive a second message from the terminal; a sending module 801, further configured to send a terminal access request message to the second network device; the receiving module, further configured to receive a terminal access request response message from the second network device, where the terminal access request response message includes the estimated time advance of the second network device; wherein, the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is the temporary identifier re-assigned by the second network device to the terminal.

[0464] In one implementable manner, the receiving module is further configured to receive a second message from the terminal; the sending module 801 is further configured to send a terminal access request message to the second network device; the receiving module is further configured to receive a terminal access request response message from the second network device, where the terminal access request response message includes the ephemeris information of the second network device.

[0465] In one implementable manner, the terminal access request response message further includes: the system message of the second network device; wherein, the system message includes preamble configuration information, the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity, the first preamble is one of the at least one preamble, and the first transmission time of the first preamble is one of the at least one random access opportunity.

[0466] In one implementable manner, the terminal access request response message further includes preamble configuration information; wherein, the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity, the first preamble is one of the at least one preamble, and the first transmission time of the first preamble is one of the at least one random access opportunity.

[0467] In one implementable manner, the terminal access request response message further includes at least one of the following parameters: a first temporary terminal identifier of the terminal, wireless configuration information configured by the second network device for the terminal, frequency point information of the second network device, PUSCH configuration information for transmitting the first message, subcarrier spacing information of the second network device, or preamble sequence number information; wherein, the preamble sequence number information is used to indicate a first preamble, and the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is a temporary identifier re-assigned by the second network device to the terminal.

[0468] In one implementable manner, the second message includes at least one of the following parameters: location information of the terminal, preset network device information, or service type information.

[0469] In one implementable manner, the second message is one of the following: an RRC connection establishment request message, an RRC reestablishment request message, a handover request message, or a redirection request message.

[0470] In one implementable manner, the third message is one of the following: an RRC connection establishment message, an RRC connection reestablishment message, a handover command message, or a redirection command message. In one implementable manner, the orbital altitude of the first network device is different from that of the second network device.

[0471] Figure 9 It is a schematic block diagram of a communication device shown in an embodiment of the present application. As Figure 9 shown, the communication device 900 may be a terminal; or a network device, such as a first network device, a second network device, etc., which is not specifically limited here. The communication device 900 can be used to implement the method described in the above method embodiments. For specific details, reference can be made to the description in the above method embodiments.

[0472] The communication device 900 includes a processor 91 and a memory 92 communicatively connected to the processor 91.

[0473] The memory 92 is used to store computer execution instructions.

[0474] The processor 91 is used to execute the computer execution instructions stored in the memory, so as to enable the communication device 900 to execute the above method.

[0475] In some embodiments, the communication device 900 may further include a transceiver 93. The transceiver 93 may include: a transmitter and / or a receiver. The transmitter may also be referred to as a sender, a transmitter, a transmission port, or a transmission interface, etc. Similar descriptions apply, and the receiver may also be referred to as a receiver, a reception port, or a reception interface, etc. Exemplarily, each of the memory 92, the processor 91, and the transceiver 93 is interconnected through a bus 94.

[0476] The processor 90 may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The steps of the method disclosed in conjunction with the present application may be directly embodied as being executed and completed by a hardware processor, or may be executed and completed by a combination of hardware and software modules in the processor.

[0477] In some embodiments, all or part of the memory 92 may also be outside the communication device 900.

[0478] In some embodiments, if the communication device 900 is a terminal, then the terminal includes: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the communication method performed by the terminal as described above.

[0479] In some embodiments, if the communication device 900 is a second network device, then the second network device includes: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the communication method performed by the second network device as described above.

[0480] In some embodiments, if the communication device 900 is a first network device, then the first network device includes: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the communication method performed by the first network device as described above.

[0481] The embodiments of the present application further provide a computer-readable storage medium, in which computer-executable instructions are stored, and when the computer-executable instructions are executed by a processor, they are used to implement the communication method shown in any of the above embodiments.

[0482] The embodiments of the present application further provide a computer program product, including a computer program, and when the computer program is executed by a processor, it implements the communication method shown in any of the above embodiments.

[0483] Other embodiments of the present application will be readily apparent to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. The present application is intended to cover any variations, uses, or adaptations of the present application, which follow the general principles of the present application and include known common knowledge or conventional technical means in the technical field not disclosed in the present application. The specification and examples are only illustrative, and the true scope and spirit of the present application are pointed out by the following claims.

[0484] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present application is only limited by the appended claims.

Claims

1. A communication method, characterized in that, Applied to a terminal, the terminal resides in a first network device, and the method includes: Advance the estimated time advance of a second network device by a second time at a first transmission time, and send a first preamble to the second network device; Advance the estimated time advance at a second transmission time, and send a first message to the second network device on a physical uplink shared channel PUSCH corresponding to the first preamble; wherein, the second transmission time is separated from the first transmission time by a first preset time.

2. The method according to claim 1, wherein The sending the first preamble to the second network device includes: Send the first preamble to the second network device according to preamble configuration information, the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity, the first preamble is one of the at least one preamble, and the first transmission time of the first preamble is one of the at least one random access opportunity.

3. The method according to claim 1, wherein The first preset time is predefined, or, the first preset time is sent by the first network device.

4. The method according to any one of claims 1 to 3, characterized in that, The first message is one of the following: a radio resource control RRC connection establishment completion message, an RRC reconstruction completion message, a handover completion message, an RRC reconfiguration completion message, or a redirection completion message.

5. The method according to claim 1, wherein Before the sending the first preamble to the second network device, the method further includes: Send a second message to the first network device; Receive a third message from the first network device, the third message includes the estimated time advance.

6. The method according to claim 5, wherein The third message includes radio configuration information configured by the second network device for the terminal.

7. The method according to claim 6, wherein The third message further includes frequency point information of the second network device.

8. The method according to claim 5, characterized in that The third message further includes a first temporary terminal identifier of the terminal, the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is a temporary identifier re-assigned by the second network device to the terminal.

9. The method according to any one of claims 5 - 8, characterized in that Obtain the preamble configuration information by one of the following methods: Receive system information broadcast by the second network device, the system information includes the preamble configuration information; The third message further includes system information of the second network device, the system information includes the preamble configuration information; The third message further includes the preamble configuration information.

10. The method according to claim 5, characterized in that, The third message further includes at least one of the following parameters: ephemeris information of the second network device, PUSCH configuration information for transmitting the first message, subcarrier spacing information of the second network device, or preamble sequence number information, the preamble sequence number information is used to indicate the first preamble.

11. The method according to claim 1, characterized in that, Before the sending the first preamble to the second network device, the method further includes: Send a second message to the first network device; Receive a third message from the first network device, the third message includes ephemeris information of the second network device; Determine the estimated time advance of the second network device based on the ephemeris information of the second network device.

12. The method according to claim 11, wherein The terminal obtains the preamble configuration information by one of the following methods: Receive system information broadcast by the second network device, the system information includes the preamble configuration information; The third message further includes the system message of the second network device, and the system message includes the preamble configuration information; The third message further includes the preamble configuration information.

13. The method according to claim 11 or 12, characterized in that, The third message further includes at least one of the following parameters: the wireless configuration information configured by the second network device for the terminal, the frequency point information of the second network device, and the first temporary terminal identifier of the terminal, where the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is the temporary identifier re-assigned by the second network device to the terminal.

14. The method according to claim 11, wherein The third message further includes at least one of the following parameters: the PUSCH configuration information for transmitting the first message, the subcarrier spacing information of the second network device, or the preamble sequence number information, where the preamble sequence number information is used to indicate the first preamble.

15. The method according to claim 5, wherein The second message includes at least one of the following parameters: the location information of the terminal, the preset network device information, or the service type information.

16. The method according to claim 5, wherein The second message is one of the following: an RRC connection establishment request message, an RRC re-establishment request message, a handover request message, or a redirection request message.

17. The method according to claim 5, wherein The third message is one of the following: an RRC connection establishment message, an RRC connection re-establishment message, a handover command message, or a redirection command message.

18. The method according to claim 1, characterized in that, After sending the first message to the second network device on the physical uplink shared channel PUSCH corresponding to the first preamble, the method further includes: Receiving a first timing advance from the second network device.

19. The method according to claim 1, wherein The orbital altitude of the first network device is different from that of the second network device.

20. A communication method, characterized in that, Applied to the second network device, the method includes: Receiving a first preamble from a terminal; the terminal camps on a first network device, and the first preamble is sent at a first transmission timing advance of the estimated timing advance of the second network device; Determining timing offset information according to the actual reception time window of the first preamble, where the timing offset information is used to indicate the time offset between the actual reception time window of the first preamble and the preset reception time window of the first preamble; Receiving a first message on the physical uplink shared channel PUSCH corresponding to the first preamble according to the timing offset information; the first message is sent at a second transmission timing advance of the estimated timing advance, and on the PUSCH, the second transmission timing is separated from the first transmission timing by a first preset time.

21. The method according to claim 20, wherein The first message is at least one of the following: an RRC connection establishment completion message, an RRC re-establishment completion message, a handover completion message, an RRC reconfiguration completion message, or a redirection completion message.

22. The method according to claim 20, wherein Before receiving the first preamble from the terminal, the method further includes: Receiving a terminal access request message from the first network device; Sending a terminal access request response message to the first network device, where the terminal access request response message includes the estimated timing advance of the second network device; Wherein, the estimated timing advance of the second network device is obtained according to the location information of the terminal.

23. The method according to claim 20, wherein Before receiving the first preamble from the terminal, the method further includes: Receiving a terminal access request message from a first network device; Sending a terminal access request response message to the first network device, where the terminal access request response message includes ephemeris information of the second network device.

24. The method according to claim 22 or 23, characterized in that, The terminal access request response message further includes: system information of the second network device; where The system information includes preamble configuration information for indicating at least one preamble and at least one random access occasion. The first preamble is one of the at least one preambles, and the first transmission time of the first preamble is one of the at least one random access occasions.

25. The method according to claim 22 or 23, characterized in that The terminal access request response message further includes preamble configuration information; where the preamble configuration information is used to indicate at least one preamble and at least one random access occasion. The first preamble is one of the at least one preambles, and the first transmission time of the first preamble is one of the at least one random access occasions.

26. The method according to claim 22 or 23, characterized in that, The terminal access request response message further includes at least one of the following parameters: a first temporary terminal identifier of the terminal, PUSCH configuration information for transmitting the first message, subcarrier spacing information of the second network device, radio configuration information configured by the second network device for the terminal, frequency point information of the second network device, or preamble sequence number information; where The preamble sequence number information is used to indicate the first preamble, and the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is a temporary identifier re - assigned by the second network device to the terminal.

27. The method according to any one of claims 20-23, characterized in that, After receiving the first message on a physical uplink shared channel (PUSCH) corresponding to the first preamble according to the timing offset information, the method further includes: Sending a first timing advance to the terminal.

28. The method according to any one of claims 20-23, characterized in that, The orbital altitude of the first network device is different from that of the second network device.

29. A communication method, characterized in that, Applied to a first network device, the method includes: Sending a third message to the terminal, where the third message includes information for the terminal to determine an estimated timing advance of the second network device. The information for the terminal to determine the estimated timing advance of the second network device includes at least one of the estimated timing advance of the second network device or the ephemeris information of the second network device; The third message further includes at least one of the following parameters: a first temporary terminal identifier of the terminal, radio configuration information configured by the second network device for the terminal, frequency point information of the second network device, PUSCH configuration information for transmitting the first message, subcarrier spacing information of the second network device, or preamble sequence number information; where The preamble sequence number information is used to indicate the first preamble, and the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is a temporary identifier re - assigned by the second network device to the terminal.

30. The method according to claim 29, wherein The third message further includes system information of the second network device; where The system message includes preamble configuration information, and the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity.

31. The method according to claim 29 or 30, characterized in that, The third message further includes preamble configuration information; wherein, the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity.

32. The method according to claim 29, wherein Before sending the third message to the terminal, the method further includes: Receiving a second message from the terminal; Sending a terminal access request message to the second network device; Receiving a terminal access request response message from the second network device, where the terminal access request response message includes the estimated time advance of the second network device.

33. The method according to claim 29, wherein Before sending the third message to the terminal, the method further includes: Receiving a second message from the terminal; Sending a terminal access request message to the second network device; Receiving a terminal access request response message from the second network device, where the terminal access request response message includes the ephemeris information of the second network device.

34. The method according to claim 32 or 33, characterized in that, The terminal access request response message further includes: the system message of the second network device; wherein, The system message includes preamble configuration information, the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity, the first preamble is one of the at least one preamble, and the first transmission time of the first preamble is one of the at least one random access opportunity.

35. The method according to claim 32 or 33, characterized in that, The terminal access request response message further includes preamble configuration information; wherein, the preamble configuration information is used to indicate at least one preamble and at least one random access opportunity, the first preamble is one of the at least one preamble, and the first transmission time of the first preamble is one of the at least one random access opportunity.

36. The method according to claim 32 or 33, characterized in that, The terminal access request response message further includes at least one of the following parameters: the first temporary terminal identifier of the terminal, the wireless configuration information configured by the second network device for the terminal, the frequency point information of the second network device, the PUSCH configuration information for transmitting the first message, the subcarrier spacing information of the second network device, or the preamble sequence number information; wherein, The preamble sequence number information is used to indicate the first preamble, and the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is the temporary identifier re-assigned by the second network device to the terminal.

37. The method according to claim 32 or 33, characterized in that, The second message includes at least one of the following parameters: the location information of the terminal, the preset network device information, or the service type information.

38. The method according to claim 32 or 33, characterized in that, The second message is one of the following: an RRC connection establishment request message, an RRC reestablishment request message, a handover request message, or a redirection request message.

39. The method according to claim 29, wherein The third message is one of the following: an RRC connection establishment message, an RRC connection reestablishment message, a handover command message, or a redirection command message.

40. The method according to claim 29, characterized in that, The orbital altitude of the first network device is different from that of the second network device.

41. A communication device, characterized in that, Applied to a terminal, the terminal camps on the first network device, and the device includes: A sending module, configured to advance the estimated time advance of a second network device by a first sending time, and send a first preamble to the second network device; The sending module is further configured to advance the estimated time advance at a second sending time, and send a first message to the second network device on a physical uplink shared channel PUSCH corresponding to the first preamble; wherein, the second sending time and the first sending time are separated by a first preset time.

42. A communication device, characterized in that, Applied to a second network device, the apparatus includes: A receiving module, configured to receive a first preamble from a terminal; the terminal camps on a first network device, and the first preamble is sent by advancing the estimated time advance of the second network device at a first sending time; A processing module, configured to determine timing offset information according to an actual reception time window of the first preamble, where the timing offset information is used to indicate a time offset between the actual reception time window of the first preamble and a preset reception time window of the first preamble; The receiving module is further configured to receive a first message on a physical uplink shared channel PUSCH corresponding to the first preamble according to the timing offset information; the first message is sent by advancing the estimated time advance at a second sending time, and on the PUSCH, the second sending time and the first sending time are separated by a first preset time.

43. A communication device, characterized in that, Applied to a first network device, the apparatus includes: A sending module, configured to send a third message to a terminal, where the third message includes information for the terminal to determine an estimated time advance of a second network device, and the information for the terminal to determine the estimated time advance of the second network device includes at least one of an estimated time advance of the second network device or ephemeris information of the second network device; The third message further includes at least one of the following parameters: a first temporary terminal identifier of the terminal, radio configuration information configured by the second network device for the terminal, frequency point information of the second network device, PUSCH configuration information for transmitting the first message, subcarrier spacing information of the second network device, or preamble sequence number information; wherein, The preamble sequence number information is used to indicate the first preamble, and the first temporary terminal identifier is the same as the temporary identifier assigned by the first network device to the terminal or is a temporary identifier re-assigned by the second network device to the terminal.

44. A terminal, characterized in that, Comprising: A processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method according to any one of claims 1-19.

45. A second network device, characterized in that, Comprising: A processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method according to any one of claims 20-28.

46. A first network device, characterized in that, Comprising: A processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method according to any one of claims 29-40.

47. A computer-readable storage medium, characterized in that, Computer-executable instructions are stored in the computer-readable storage medium, and when the computer-executable instructions are executed by a processor, they are used to implement the method according to any one of claims 1-40.

48. A computer program product, characterized in that, It includes a computer program which, when executed by a processor, implements the method according to any one of claims 1-40.

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