Communication method and device

Abstract

The invention relates to the technical field of communication, and provides a communication method and device. In the method, before receiving a random access lead code from terminal equipment, network equipment sends a random access response message to the terminal equipment, and for different terminal equipment, the network equipment can respectively indicate different timing advance through different random access response messages. The time for different terminal devices to send messages (such as Msg3) to the network device is staggered, so that mutual interference of the messages sent by the different terminal devices is reduced, the probability that the network device cannot successfully receive the messages of the terminal devices is reduced, and the access success rate of the terminal devices is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of communication technology, and in particular, to a communication method and device. Background Art

[0002] Under a random access (RA) mechanism, the network device sends a random access response (RAR) message to the terminal device before receiving the random access preamble (preamble) from the terminal device. Correspondingly, the terminal device receives the RAR message from the network device. If the terminal device completes the reception of the RAR message in time slot (slot) n, the terminal device can feedback message 3 (Msg3) to the network device in time slot (n+X) to request to establish a connection with the network device. In the long term evolution (LTE) system, X is, for example, 6; in the new radio (NR) system, X is, for example, 3, 4, 5 or 6. Time slot (n+X) can represent a time slot numbered (n+X). If the time slot numbering starts from 0, the time slot (n+X) can be the (n+X+1)th time slot.

[0003] Under this random access mechanism, since the network device does not receive the random access preamble from the terminal device when sending the RAR message, it is impossible to estimate the round-trip delay between the terminal device and the network device, so the terminal device does not complete uplink synchronization when sending Msg3. Different terminal devices send Msg3 according to the above-mentioned time slot (n+X) mechanism. There may be interference between the Msg3 sent by different terminal devices, resulting in the network device being unable to correctly receive the Msg3 of the terminal device, which in turn causes the terminal device to fail to access. Summary of the invention

[0004] The embodiments of the present application provide a communication method and apparatus for improving the success rate of terminal device access.

[0005] In the first aspect, an embodiment of the present application provides a communication method, which can be executed by a network device, a software module or a hardware module (such as a chip) in the network device. For ease of description, the following is an example of a network device executing the method. The method includes: before receiving a first random access preamble from a first terminal device, sending a first random access response message, the first random access response message indicating a first timing advance, the first timing advance is used to determine a first time window for receiving the first message, and the first message is used to request to establish a connection between the first terminal device and the network device; before receiving a second random access preamble from a second terminal device, sending a second random access response message, the second random access response message indicating a second timing advance, the second timing advance is used to determine a second time window for receiving the second message, and the second message is used to request to establish a connection between the second terminal device and the network device, wherein the duration of the overlap between the second time window and the first time window is less than or equal to the first threshold.

[0006] In an embodiment of the present application, before receiving the random access preamble of the terminal device, the network device indicates the timing advance to the terminal device, so that different terminal devices (such as the first terminal device and the second terminal device) can stagger the time windows for sending messages (such as the first message and the second message) based on the timing advance indicated by the network device, and thus stagger the time windows for the network device to receive messages from different terminal devices, thereby reducing interference between messages from different terminal devices, reducing the probability of failure of the network device to receive messages from terminal devices, and improving the access success rate of terminal devices. In addition, the network device can flexibly indicate the timing advance of different terminal devices, so that the network device does not need to adjust the time of sending random access response messages to stagger the time of sending messages from different terminal devices, so that the network device can send relatively more random access response messages within a certain period of time, thereby improving the access capacity of the network device, allowing different terminal devices to access more timely, and improving the access efficiency of terminal devices. Moreover, in the embodiment of the present application, the terminal device can send a message based on the timing advance, and the terminal device does not need to perform additional operations. On the one hand, the capability requirements of the terminal device are low, and on the other hand, there is no need to modify the terminal device, so that the solution provided by the embodiment of the present application can be applied to existing terminal devices, that is, the solution provided by the embodiment of the present application has good universality. Moreover, since the network device can indicate different timing advances to different terminal devices, different terminal devices can perform delay compensation based on the timing advance, so that the embodiment of the present application can be applied to scenarios with high communication delays such as non-terrestrial networks.

[0007] In one possible implementation, the difference between the first timing advance and the second timing advance satisfies one of the following: greater than or equal to the first value; or, greater than or equal to the second value; wherein the second value is the difference between the first value and the first threshold, the first value is the maximum value among multiple third values, and any third value among the multiple third values ​​is the difference in round-trip delays between the network device and two terminal devices, respectively, and the two terminal devices are any two terminal devices within the coverage range of at least one beam of the network device.

[0008] In the above embodiment, an implementation method for relatively staggering the first time window and the second time window is provided. For example, the network device can control the difference between the first timing advance and the second timing advance to be relatively large. In this way, even if the round-trip delay between different terminal devices and the network device is large, different terminal devices can still relatively stagger the time windows for sending messages, thereby ensuring that the network device can successfully receive the message of the terminal device and improving the access success rate of the terminal device.

[0009] In one possible implementation, the first threshold is zero; or, the first threshold is determined based on one or more cyclic prefixes in the cyclic prefixes of M time units, for example, the first threshold is the length of the first cyclic prefix in the cyclic prefixes of M time units, or the first threshold is determined based on the length of the cyclic prefixes of M time units; wherein the first message and / or the second message is received over M time units, and M is an integer greater than 1.

[0010] In the above implementation, when the first threshold is zero, it is equivalent to that there is no overlap between the first time window and the second time window; when the first threshold is one or more cyclic prefixes in the cyclic prefix based on M time units, it is equivalent to that the overlap duration of the first time window and the second time window is short. There is no overlap between the first time window and the second time window, or the overlap duration is short, and the network device can successfully receive messages from different terminal devices, thereby improving the access success rate of different terminal devices. In addition, since the overlap duration of the first time window and the second time window is short, the network device can receive more messages from different terminal devices within a certain time, so that the network device can access more terminal devices within a certain time.

[0011] In a possible implementation, the first cyclic prefix is ​​one of the following: a cyclic prefix of any time unit among the M time units; or a cyclic prefix with the largest length among the M time units; or a cyclic prefix with the smallest length among the M time units.

[0012] In the above implementation, multiple methods of the first threshold are provided, and the implementation methods of the first threshold are enriched. For example, the first threshold may be the length of the cyclic prefix of any time unit in the M time units, thereby increasing the flexibility of the value of the first threshold. Alternatively, the first threshold is the length of the cyclic prefix with the largest length of the M time units, so that the value of the first threshold is relatively large. Alternatively, the first threshold is the length of the cyclic prefix with the smallest length of the M time units, so that the overlapping duration of the first time window and the second time window is sufficiently small, which is beneficial to increasing the success rate of the network device receiving messages from different terminal devices.

[0013] In a possible implementation manner, another implementation manner of the first threshold is provided. For example, the first threshold is an average value of the lengths of cyclic prefixes of M time units.

[0014] In a possible implementation, the method further includes: receiving a first message from a first terminal device within a first time window; and / or receiving a second message from a second terminal device within a second time window.

[0015] In a possible implementation, the method further includes: determining a third time window for the first terminal device to send the first message according to the first timing advance, and determining the first time window according to the third time window; and / or determining a fourth time window for the second terminal device to send the second message according to the second timing advance, and determining the second time window according to the fourth time window. Optionally, the start time of the first time window is equal to or later than the start time of the third time window, and / or the start time of the second time window is equal to or later than the start time of the fourth time window.

[0016] In the above embodiment, a method is provided for the network device to determine the first time window and / or the second time window. The network device can determine the time window for the terminal device to send a message based on the timing advance, and then determine the time window for receiving the message from the terminal device, so that the network device can receive the message from the terminal device in a timely manner.

[0017] In a possible implementation, the network device is a network device in a non-terrestrial network. For example, the network device may be a satellite or a satellite ground station in the non-terrestrial network.

[0018] In a second aspect, an embodiment of the present application provides a communication method, which can be executed by a network device, a software module or a hardware module (such as a chip) in the network device. For ease of description, the following is an example of a network device executing the method. The method includes: sending a first timing advance to a first terminal device, the first timing advance is used to determine a first time window for receiving a first message, the start time of the first time window is different from the start time of the first time unit, and the first message is used to request to establish a connection between the first terminal device and the network device; sending a second timing advance to a second terminal device, the second timing advance is used to determine a second time window for receiving a second message, the start time of the second time window is different from the start time of the second time unit, and the time interval between the start time of the first time window and the start time of the second time window is N time units, N is a natural number, and the second message is used to request to establish a connection between the first terminal device and the network device; in the first time window, receiving a first message from the first terminal device; in the second time window, receiving a second message from the second terminal device.

[0019] In the embodiment of the present application, the first time window does not have to be aligned with the start time of the first time unit, and the second time window does not have to be aligned with the start time of the second time unit. Compared with the scheme in which the start time of the time window of the network device receiving the message of the terminal device is aligned with the start time of the time unit, the flexibility of the start time of the first time window and the second time window is improved. Since the start time of the first time window and the second time window does not have to be aligned with the start time of the time unit, the value selection method of the first advance amount and the second advance amount is more flexible. In addition, the start time of the first time window and the start time of the second time window can be aligned, or differ by a positive integer number of time units, so that the network device can use frequency division or space division to receive the first message and the second message, thereby improving the success rate of the network device receiving the first message and the second message.

[0020] In a possible implementation, the method further includes: determining a first round-trip delay between the network device and the first terminal device; performing a modulus operation on the first round-trip delay to determine a first remainder; and subtracting a first duration from the first remainder to determine a first timing advance.

[0021] In the above embodiment, an implementation method for the network device to determine the first timing advance is provided. For example, the network device can perform further operations on the first remainder so that the value of the first timing advance is relatively small, thereby avoiding the situation where the value of the first timing advance is too large and the first terminal device cannot accurately or successfully perform delay compensation.

[0022] In one possible implementation, before determining the first timing advance by subtracting the first duration from the first remainder, the method further includes: determining that the first remainder is greater than the second duration. In another possible implementation, if the first remainder is less than or equal to the second duration, the first timing advance is the first remainder.

[0023] In the above implementation, a flexible method for determining the first timing advance is provided. If the first remainder is large, the result of subtracting the first duration from the first remainder is used as the first timing advance, thereby avoiding the situation where the first timing advance is too large. If the first remainder is small, the first remainder can be used as the first timing advance, which can relatively simplify the calculation process of the network device.

[0024] In a possible implementation, determining a first round-trip delay between a network device and a first terminal device includes: receiving a first random access preamble from the first terminal device; and determining the first round-trip delay based on a time when the first random access preamble is received.

[0025] In the above implementation, the network device can estimate the round-trip delay between the network device and the first terminal device based on the time of receiving the first random access preamble code, providing a method for determining the first round-trip delay.

[0026] In a possible implementation, the method further includes: determining a second round-trip delay between the network device and the second terminal device; performing a modulus operation on the second round-trip delay to determine a second remainder; and subtracting the first duration from the second remainder to determine a second timing advance.

[0027] In the above embodiment, an implementation method for the network device to determine the second timing advance is provided. For example, the network device can perform further operations on the second remainder so that the value of the second timing advance is relatively small, thereby avoiding the situation where the value of the second timing advance is too large and the second terminal device cannot accurately or successfully perform delay compensation.

[0028] In one possible implementation, before determining the second timing advance by subtracting the first duration from the second remainder, the method further includes: determining that the second remainder is greater than the second duration. In another possible implementation, if the second remainder is less than or equal to the second duration, the second timing advance is the second remainder.

[0029] In the above implementation, a flexible method for determining the second timing advance is provided, such as when the network device determines that the second remainder is large, the second remainder is subtracted from the second duration, thereby avoiding the situation where the second timing advance is too large. If the second remainder is small, the second remainder can be used as the second timing advance, which can relatively simplify the calculation process of the network device.

[0030] In a possible implementation, determining a second round trip delay between the network device and the second terminal device includes: receiving a second random access preamble from the second terminal device; and determining the second round trip delay based on a time of receiving the second random access preamble.

[0031] In the above implementation, the network device can estimate the round-trip delay between the network device and the first terminal device based on the time of receiving the first random access preamble code, providing a method for determining the second round-trip delay.

[0032] In a possible implementation, the network device is a network device in a non-terrestrial network. For example, the network device may be a satellite or a satellite ground station in the non-terrestrial network.

[0033] In a third aspect, an embodiment of the present application provides a communication device, which may be a network device in the first aspect and any possible implementation, or a software module or hardware module (such as a chip) configured in the network device, or a device having a network device function. The communication device includes corresponding means (means) or modules for executing the first aspect or any possible implementation. For example, the communication device includes a processing module (sometimes also referred to as a processing unit), and a transceiver module (sometimes also referred to as a transceiver unit).

[0034] For example, under the control of the processing module, the transceiver module is used to: send a first random access response message, the first random access response message indicates a first timing advance, the first timing advance is used to determine a first time window for receiving a first message, and the first message is used to request to establish a connection between a first terminal device and a network device; receive a first random access preamble from the first terminal device, and the first random access preamble is received after sending the first random access response message; send a second random access response message, the second random access response message indicates a second timing advance, and the second timing advance is used to determine a second time window for receiving a second message, and the second message is used to request to establish a connection between a second terminal device and a network device, wherein the duration of overlap between the second time window and the first time window is less than or equal to a first threshold; receive a second random access preamble from the second terminal device, and the second random access preamble is received after sending the second random access response message.

[0035] The communication device can also implement the steps performed by the network device in the first aspect and any possible implementation manner described above, which are not listed here.

[0036] In a fourth aspect, an embodiment of the present application provides a communication system, which includes a network device, a first terminal device, and a second terminal device. The function of the network device can realize the function of the network device involved in any of the first aspect and any possible implementation methods, the network device is, for example, the network device involved in the third aspect, the function of the first terminal device can refer to the function of the first terminal device involved in any of the first aspect and any possible implementation methods, and the function of the second terminal device can refer to the function of the second terminal device involved in any of the first aspect and any possible implementation methods.

[0037] In a fifth aspect, an embodiment of the present application provides a communication device, which may be a network device in the second aspect and any possible implementation, or a software module or hardware module (such as a chip) configured in the network device, or a device having a network device function. The communication device includes corresponding means (means) or modules for executing the second aspect or any possible implementation. For example, the communication device includes a processing module (sometimes also referred to as a processing unit), and a transceiver module (sometimes also referred to as a transceiver unit).

[0038] For example, under the control of the processing module, the transceiver module is used to: send a first timing advance to a first terminal device, the first timing advance is used to determine a first time window for receiving a first message, the start time of the first time window is different from the start time of the first time unit, and the first message is used to request to establish a connection between the first terminal device and the network device; send a second timing advance to a second terminal device, the second timing advance is used to determine a second time window for receiving a second message, the start time of the second time window is different from the start time of the second time unit, and the time interval between the start time of the first time window and the start time of the second time window is N time units, N is a natural number, and the second message is used to request to establish a connection between the first terminal device and the network device; within the first time window, receive a first message from the first terminal device; within the second time window, receive a second message from the second terminal device.

[0039] In a possible implementation, the processing module is also used to: determine a first round-trip delay between the network device and the first terminal device; perform a modulus operation on the first round-trip delay to determine a first remainder; and subtract the first duration from the first remainder to determine a first timing advance.

[0040] In a possible implementation manner, the processing module is further configured to: before determining the first timing advance by subtracting the first duration from the first remainder, determine that the first remainder is greater than the second duration.

[0041] In a possible implementation, the processing module is specifically used to: receive a first random access preamble code from a first terminal device; and determine a first round-trip delay according to a time when the first random access preamble code is received.

[0042] In a possible implementation, the processing module is further used to: determine a second round-trip delay between the network device and the second terminal device; perform a modulus operation on the second round-trip delay to determine a second remainder; and subtract the first duration from the second remainder to determine a second timing advance.

[0043] In a possible implementation manner, the processing module is further configured to: before determining the second timing advance by subtracting the first duration from the second remainder, determine that the second remainder is greater than the second duration.

[0044] In a possible implementation, the processing module is specifically used to: receive a second random access preamble from a second terminal device; and determine a second round-trip delay according to a time when the second random access preamble is received.

[0045] In a sixth aspect, an embodiment of the present application provides a communication system, which includes a network device, a first terminal device, and a second terminal device. The function of the network device can realize the function of the network device involved in any of the second aspect and any possible implementation methods, the network device is, for example, the network device involved in the fifth aspect, the function of the first terminal device can refer to the function of the first terminal device involved in any of the second aspect and any possible implementation methods, and the function of the second terminal device can refer to the function of the second terminal device involved in any of the second aspect and any possible implementation methods.

[0046] In the seventh aspect, an embodiment of the present application provides a communication device, comprising a processor and an interface circuit, wherein the interface circuit is used to receive signals from other communication devices outside the communication device and transmit them to the processor or send signals from the processor to other communication devices outside the communication device, and the processor is used to implement a method as described in the first aspect, the second aspect and any possible implementation method through a logic circuit or by executing code instructions.

[0047] In the specific implementation process, the communication device can be a chip, the input circuit can be an input pin, the output circuit can be an output pin, and the processing circuit can be a transistor, a gate circuit, a trigger, and various logic circuits. The input signal received by the input circuit can be, for example, but not limited to, received and input by a receiver, and the signal output by the output circuit can be, for example, but not limited to, output to a transmitter and transmitted by the transmitter, and the input circuit and the output circuit can be the same circuit, which is used as an input circuit and an output circuit at different times. The embodiments of the present application do not limit the specific implementation methods of the processor and various circuits.

[0048] In one implementation, the communication device may be a wireless communication device, that is, a computer device that supports wireless communication functions. Specifically, the wireless communication device may be a terminal such as a smart phone, or a wireless access network device such as a base station. The system chip may also be referred to as a system on chip (SoC), or simply as an SoC chip. The communication chip may include a baseband processing chip and a radio frequency processing chip. The baseband processing chip is sometimes also referred to as a modem or a baseband chip. The radio frequency processing chip is sometimes also referred to as a radio frequency transceiver or a radio frequency chip. In a physical implementation, some or all of the chips in the communication chip may be integrated inside the SoC chip. For example, the baseband processing chip is integrated in the SoC chip, and the radio frequency processing chip is not integrated with the SoC chip. The interface circuit may be a radio frequency processing chip in a wireless communication device, and the processing circuit may be a baseband processing chip in a wireless communication device.

[0049] In another implementation, the communication device may be a part of a wireless communication device, such as an integrated circuit product such as a system chip or a communication chip. The interface circuit may be an input / output interface, an interface circuit, an output circuit, an input circuit, a pin or a related circuit on the chip or the chip system. The processor may also be embodied as a processing circuit or a logic circuit.

[0050] In an eighth aspect, an embodiment of the present application provides a communication device, comprising: a processor and a memory; the memory is used to store one or more computer programs, and the one or more computer programs include computer execution instructions. When the communication device is running, the processor executes the one or more computer programs stored in the memory, so that the communication device performs any method as described in the first aspect and the second aspect and any possible implementation manner.

[0051] Optionally, the communication device further includes other components, such as an antenna, an input / output module, an interface, etc. These components may be hardware, software, or a combination of software and hardware.

[0052] In a ninth aspect, an embodiment of the present application provides a chip system, the chip system comprising: a processor and an interface. The processor is used to call and run instructions from the interface, and when the processor executes the instructions, the method described in the first aspect, the second aspect and any possible implementation method is implemented.

[0053] In the tenth aspect, an embodiment of the present application provides a computer-readable storage medium, which is used to store computer programs or instructions. When the computer-readable storage medium is executed, it implements the method described in the first aspect, the second aspect and any possible implementation method.

[0054] In an eleventh aspect, an embodiment of the present application provides a computer program product comprising instructions, which, when executed on a computer, implements a method as described in the first aspect and the second aspect and any possible implementation manner.

[0055] In a twelfth aspect, an embodiment of the present application provides a communication system, including a network device and a terminal device, and the network device can be used to execute any method described in the first aspect, the second aspect and any possible implementation manner.

[0056] Regarding the beneficial effects of any technical solution in the third to eleventh aspects above, reference can be made to the beneficial effects discussion of the corresponding technical solution in the first or second aspect, and the repeated parts will not be listed here. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 is a schematic diagram of a random access process;

[0058] Figure 2 A schematic diagram of a communication system provided in an embodiment of the present application;

[0059] Figure 3 A schematic diagram of a satellite system in a transparent transmission mode applicable to an embodiment of the present application;

[0060] Figure 4 A schematic diagram of a satellite system in another transparent transmission mode applicable to an embodiment of the present application;

[0061] Figure 5 A schematic diagram of a satellite system in a regeneration mode applicable to an embodiment of the present application;

[0062] Figure 6 A schematic diagram of a satellite system in another regeneration mode applicable to an embodiment of the present application;

[0063] Figure 7 A schematic diagram of a communication method provided in an embodiment of the present application;

[0064] Figure 8 A schematic diagram of a round-trip delay between a network device and a terminal device provided in an embodiment of the present application;

[0065] Fig. 9 A schematic diagram of a random access process provided in an embodiment of the present application;

[0066] Fig.10 A schematic diagram of a random access process provided in an embodiment of the present application;

[0067] Fig.11A time window for a network device under another random access mechanism to receive Msg3 from different terminal devices;

[0068] Fig.12 A schematic diagram of another communication method provided in an embodiment of the present application;

[0069] Fig.13 A time window for a network device to receive messages from different terminal devices is provided for an embodiment of the present application;

[0070] Fig.14 A schematic diagram of the structure of a communication device provided in an embodiment of the present application;

[0071] Fig.15 A schematic diagram of the structure of another communication device provided in an embodiment of the present application;

[0072] Fig.16 A schematic diagram of the structure of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0073] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0074] Below, some terms in the embodiments of the present application are explained to facilitate understanding by those skilled in the art.

[0075] 1. A terminal device is a device with wireless transceiver functions, which can be a fixed device, a mobile device, a handheld device, a wearable device, a vehicle-mounted device, or a wireless device built into the above device (for example, a communication module or a chip system, etc.). The terminal device is used to connect people, objects, machines, etc., and can be widely used in various scenarios, such as but not limited to the following scenarios: cellular communication, device-to-device communication (D2D), vehicle to everything (V2X), machine-to-machine / machine-type communications (M2M / MTC), Internet of Things (IoT), virtual reality (VR), augmented reality (AR), industrial control, self driving, remote medical, smart grid, smart furniture, smart office, smart wear, smart transportation, smart city, drones, robots and other scenarios. The terminal device may sometimes be referred to as user equipment (UE), terminal, access station, UE station, remote station, wireless communication device, or user device, etc.

[0076] In each embodiment of the present application, the device for realizing the function of the terminal device may be the terminal device, or may be a device capable of supporting the terminal device to realize the function, such as a chip system, or may be a software module or a hardware module (such as a chip) in the terminal device. In the technical solutions provided in each embodiment of the present application, the technical solutions provided in each embodiment of the present application are described by taking the device for realizing the function of the terminal device as an example, which is a terminal device.

[0077] 2. Network equipment, for example, including access network equipment (or, referred to as access network elements), and / or core network (core network, CN) equipment (or, referred to as core network elements).

[0078] (1) Access network equipment, which is a device with wireless transceiver function, is used to communicate with the terminal device. The access network equipment includes but is not limited to base stations (BTS, Node B, eNodeB / eNB, or gNodeB / gNB) in the above communication system, transmission reception points (TRP), base stations of subsequent evolution of 3GPP, access nodes in wireless fidelity (WiFi) systems, wireless relay nodes, wireless backhaul nodes, satellites or drones and other non-ground network devices. The base station can be: macro base station, micro base station, micro-micro base station, small station, relay station, etc. Multiple base stations can support the same access technology mentioned above, or they can support the networks of different access technologies mentioned above. The base station can include one or more co-site or non-co-site transmission and reception points. The access network device can also be a wireless controller in the cloud radio access network (C(R)AN) scenario. The access network device can also be a server, a wearable device, or a vehicle-mounted device, etc. For example, the access network device in the vehicle to everything (V2X) technology may be a road side unit (RSU). The following describes the access network device by taking a base station as an example. The multiple access network devices in the communication system may be base stations of the same type or base stations of different types. The base station may communicate with the terminal device or communicate with the terminal device through a relay station. The terminal device may communicate with multiple base stations in different access technologies.

[0079] In a possible architecture of an access network device, the access network device includes a centralized unit (central unit, CU), and / or a distributed unit (distributed unit, DU). CU and DU can be understood as a division of the access network device from a logical function perspective. Among them, CU and DU can be physically separated or deployed together, and the embodiment of the present application does not specifically limit this. A CU can be connected to a DU, or multiple DUs can share a CU. The division of CU and DU can be divided according to the protocol stack, and one possible way is to deploy the radio resource control (radio resource control, RRC), service data adaptation protocol stack (service data adaptation protocol, SDAP) and packet data convergence protocol (packet data convergence protocol, PDCP) layer in the CU, and the remaining radio link control (radio link control, RLC) layer, media access control (media access control, MAC) layer and physical layer in the DU. In the embodiment of the present application, the division of CU and DU according to the above-mentioned protocol stack is not completely limited, and there may be other division methods, such as division according to service type.

[0080] The access network device in the embodiment of the present application may also refer to a centralized unit control plane (central unit-control plane, CU-CP) node or a centralized unit user plane (central unit-user plane, CU-UP) node, or include CU-CP and CU-UP. Among them, CU-CP is responsible for the control plane functions, mainly including RRC and PDCP-C. PDCP-C is mainly responsible for encryption and decryption, integrity protection, data transmission, etc. of the control plane data. CU-UP is responsible for user plane functions, mainly including service data adaptation protocol (service data adaption protocol, SDAP) and PDCP-U. Among them, SDAP is mainly responsible for processing the data of the core network and mapping the flow to the bearer. PDCP-U is mainly responsible for encryption and decryption, integrity protection, header compression, sequence number maintenance, data transmission, etc. of the data plane.

[0081] In different systems, CU (including CU-CP or CU-UP) or DU may have different names, but those skilled in the art can understand their meanings. For example, in an open radio access network (O-RAN) system, CU may also be called O-CU (open CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, and CU-UP may also be called O-CU-UP.

[0082] The core network device is used to implement at least one of the functions of mobility management, data processing, session management, policy and billing. The device names for implementing the core network functions in systems with different access technologies may be different, and the embodiments of the present application do not limit this. th Taking the 5G generation (5G) system as an example, the core network equipment includes: access and mobility management function (AMF), session management function (SMF), PCF or user plane function (UPF), etc. In each embodiment of the present application, the device for implementing the function of the network device may be a network device, or a device that can support the network device to implement the function, such as a chip system, or a software module or hardware module (such as a chip) in the network device. In the technical solutions provided in each embodiment of the present application, the technical solutions provided in each embodiment of the present application are described by taking the device for implementing the function of the network device as an example that the network device is an example.

[0083] 4. Round-trip time (RTT) refers to the round-trip time between the locations of two communicating devices, or it can also refer to the round-trip time between two locations. For example, taking the terminal device and the network device as an example, assuming that the distance between the location a of the terminal device and the location b of the network device is Sab, then RTT = Sab*2 / v, where v represents the propagation speed of electromagnetic waves.

[0084] 5. Timing advance (TA) is used to adjust the time of uplink transmission and / or downlink transmission. The duration corresponding to TA can be a compensated or adjusted duration value, and the duration corresponding to TA can be called timing advance (TA amount), TA value, TA duration, delay compensation value or delay compensation parameter, etc. For example, during uplink transmission, the terminal device can send uplink data in advance by the timing advance. In the random access phase, the network device can indicate the TA amount to the terminal device through the timing advance command (TAC) in the RAR message, that is, the TAC in the RAR message can indicate the TA amount; in the data transmission (referred to as data transmission) phase, the network device can indicate the TA amount to the terminal device through the TAC in the MAC control element (CE), that is, the TAC in the MAC CE can indicate the TA amount.

[0085] 6. A time window may refer to a continuous period of time, and a time window is also called a time period. For example, a time window is from the 1st millisecond (ms) to the 2nd ms, and for another example, a time window is from the 1st time unit to the 3rd time unit.

[0086] 7. A time unit may be a slot, a symbol, a subframe, a half frame, a frame, a mini-subframe, a mini-slot, or a transmission occasion (TO), which is not limited in the embodiments of the present application. A time unit may be regarded as the granularity of time domain resources.

[0087] 8. Symbols may be orthogonal frequency-division multiplexing (OFDM) symbols, cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) symbols, discrete Fourier transform-spread-orthogonal frequency division multiplexing (DFT-s-OFDM) symbols, or other types of symbols, which are not limited in the embodiments of the present application.

[0088] 9. Beam, which can be called spatial domain filter, spatial filter, spatial domain parameter, spatial parameter, spatial parameter, spatial domain setting, spatial setting or quasi-colocation (QCL) information, etc. A beam can be regarded as a communication resource, or as a spatial behavior of signal transmission. For example, a beam can be understood as the main lobe of the radiation pattern of an antenna array, or a beam can be understood as the distribution of signal strength formed in different transmission directions in space after the signal is transmitted by the antenna. The beam can be a wide beam, a narrow beam, or other types of beams. A beam can correspond to a transmission direction. Optionally, the network device can adjust the weights of the antenna so that the beam of the network device can point to different directions, thereby corresponding to different coverage ranges. The coverage range of the beam involved in the embodiment of the present application includes the coverage range of the beam on the ground.

[0089] The following is combined Figure 1 The schematic diagram of a random access process shown in FIG. 1 is used to illustrate the random access mechanism mentioned above. Figure 1 It is taken as an example that X is 6, the network device is a base station, and the different terminal devices include UE1 and UE2.

[0090] like Figure 1 As shown, the base station can send RAR message 1 and RAR message 2 respectively, for example, sending RAR message 1 in time slot 1 and sending RAR message 2 in time slot 2. UE1 sends a Msg3 in time slot (2+6) (hereinafter referred to as Msg3 of UE1), and UE2 sends a Msg3 in time slot (2+6) (hereinafter referred to as Msg3 of UE2). Figure 1 As shown, Msg3 of UE1 and Msg3 of UE2 interfere with each other. Figure 1 The time windows in which the base station receives Msg3 of UE1 and Msg3 of UE2 overlap, and the overlapping part can be shown as follows: Figure 1 As shown in the overlapping part, the base station cannot successfully receive Msg3 of UE1 and / or Msg3 of UE2, thereby causing access failure of UE1 and / or UE2.

[0091] In view of this, an embodiment of the present application provides a communication scheme, in which a network device (such as an access network device, specifically a base station) may send a first random access response message before receiving a first random access preamble code from a first terminal device, and send a second random access response message before receiving a second random access preamble code from a second terminal device. The first random access response message indicates a first TA amount, and the second random access response message indicates a second TA amount. For example, the first terminal device receives the first random access response message, and the second terminal device receives the second random access response message, so that the first terminal device can adjust the time for sending the first message (such as Msg3) based on the first TA amount, and the second terminal device can adjust the time for sending the second message (such as Msg3) based on the second TA amount. In this way, the overlapping duration of the time windows for the network device to receive the first message and the second message is small, or even completely non-overlapping, thereby reducing mutual interference between messages of different terminal devices, reducing the situation where the network device fails to receive messages from terminal devices, and helping to improve the success rate of terminal device access.

[0092] The communication scheme provided in the embodiments of the present application can be applied to various communication networks (or systems), for example, LTE communication networks, 5G mobile communication networks (such as NR networks), non-terrestrial networks (NTN), satellite-ground integrated communication networks, etc., the sixth generation communication network or communication networks that will appear in the process of future communication development (or future evolution), etc. NTN may be a communication network involving flying objects, and NTN may include satellite networks, high altitude platform stations (HAPS) or air-to-ground networks, etc. NTN can be deployed alone or as a supplement to the ground network. The communication scheme provided in the embodiments of the present application can also be applied to machine-to-machine (M2M) communication networks, machine type communication (MTC) communication networks or other communication networks, etc., and the embodiments of the present application do not limit this.

[0093] Please refer to Figure 2 , is a schematic diagram of a communication system provided in an embodiment of the present application. Or, Figure 2 It can also be regarded as a schematic diagram of a scenario provided by an embodiment of the present application. Figure 2As shown, the communication system includes a network device, a first terminal device, and a second terminal device. The network device can communicate with the first terminal device and the second terminal device respectively. Optionally, the first terminal device and the second terminal device can also communicate with each other. The network device is, for example, an access network device in the NTN, specifically, for example, a satellite and / or a satellite ground station. The implementation methods of the first terminal device and the second terminal device can refer to the implementation methods of the terminal devices in the previous text, and are not listed here.

[0094] in addition, Figure 2 In the example, the number of the network device, the first terminal device, and the second terminal device is 1. In fact, there is no limit to the number of the network device, the first terminal device, and the second terminal device.

[0095] The following is a description of a satellite system to which the communication solution provided in an embodiment of the present application is applicable. According to the communication mode of the satellite, the satellite system can be divided into a transparent mode and a regenerative mode. The transparent mode may also be referred to as a transparent forwarding mode. In the transparent mode, the satellite may also be referred to as a satellite base station, etc. The satellite is used for frequency conversion and forwarding signals, which are generated and sent by a satellite ground station. In the regenerative mode, a base station or a DU in a base station may be carried (or coupled) on the satellite. The satellite is able to parse and process signals received from the ground, and send the processed signals to a terminal device (such as a first terminal device or a second terminal device) to achieve signal regeneration.

[0096] Figure 3 A schematic diagram of a satellite system in a transparent transmission mode applicable to an embodiment of the present application is illustrated. Figure 3 The satellite and / or satellite ground station can be used as an example of a network device, one of the terminal devices 1 or 2 can be used as an example of a first terminal device, and the other of the terminal devices 1 or 2 can be used as an example of a second terminal device.

[0097] like Figure 3 As shown, the satellite can access the network using a non-3GPP radio protocol. A communication connection is established between any terminal device (such as terminal device 1 or terminal device 2) and the satellite, and between the satellite and the satellite ground station through a non-3GPP radio protocol interface. The satellite ground station may include an access point, and the satellite ground station and CN may communicate with each other through an NG interface (such as an N2 interface or an N3 interface, etc.), and the CN and the data network (DN) may communicate through an N6 interface.

[0098] Figure 4 A schematic diagram of a satellite system in another transparent transmission mode applicable to an embodiment of the present application is illustrated. Figure 4 The satellite and / or satellite ground station can be used as an example of a network device, one of the terminal devices 1 or 2 can be used as an example of a first terminal device, and the other of the terminal devices 1 or 2 can be used as an example of a second terminal device.

[0099] Figure 4 and Figure 3 The difference is that satellites can access the network through 3GPP wireless protocols. Figure 4 As shown in the figure, the satellite ground station is the base station, and the satellite can be equivalent to a repeater. The satellite can establish a communication connection with the satellite ground station through the Uu interface (or air interface), and any terminal device (such as terminal device 1 or terminal device 2) can establish a communication connection with the satellite through other transceivers. The interface between the satellite ground station, CN, and DN is similar to Figure 3 The similarities can be referenced to each other and will not be repeated here.

[0100] Figure 5 A schematic diagram of a satellite system in a regeneration mode applicable to an embodiment of the present application is illustrated. Figure 5 The satellite and / or satellite ground station can be used as an example of a network device, one of the terminal devices 1 or 2 can be used as an example of a first terminal device, and the other of the terminal devices 1 or 2 can be used as an example of a second terminal device.

[0101] like Figure 5 As shown in FIG. 1 , a base station is mounted in the satellite and a base station is mounted in the satellite ground station. A communication connection can be established between any terminal device (such as terminal device 1 or terminal device 2) and the satellite through the Uu interface, and a communication connection can be established between the satellite and the satellite ground station through the Xn interface. The interface between the satellite ground station, CN, and DN is similar to Figure 2 The same, the same points can be referenced, and will not be repeated here. Figure 5 In the satellite system shown, the satellite ground station may also be a gateway of the satellite and does not include a base station.

[0102] Figure 6 FIG. 1 is a schematic diagram illustrating another satellite system in a regeneration mode applicable to an embodiment of the present application. Figure 6 The satellite and / or satellite ground station can be used as an example of a network device, one of the terminal devices 1 or 2 can be used as an example of a first terminal device, and the other of the terminal devices 1 or 2 can be used as an example of a second terminal device.

[0103] like Figure 6As shown in the figure, the satellite carries the DU in the base station, and the satellite ground station contains the CU in the base station. Any terminal device (such as terminal device 1 or terminal device 2) can establish a communication connection with the satellite through the Uu interface, and the satellite and the satellite ground station can establish a communication connection through the F1 interface. The interface between the satellite ground station, CN, and DN is similar to Figure 3 The similarities can be referenced to each other and will not be repeated here.

[0104] It should be noted that in Figures 3 to 6 The satellite ground stations in the satellite system shown can all be used to connect satellites to the network. The satellite ground stations can also be called gateways, ground stations or earth stations, etc.

[0105] in addition, Figures 3 to 6 The satellite system shown does not constitute a limitation on the communication system to which the embodiments of the present application can be applied. Figures 3 to 6 The names of the devices in the satellite system are not limited. For example, in different communication scenarios, satellite ground stations or satellites may have other names. In addition, the satellites described in the embodiments of the present application may also be replaced by other non-ground network devices, such as high-altitude platform devices or high-altitude aircraft, and the embodiments of the present application do not limit this.

[0106] The following describes the method provided by the embodiments of the present application in conjunction with the accompanying drawings. In the accompanying drawings corresponding to the various embodiments of the present application, all steps indicated by dotted lines are optional steps. Also, the network devices involved in the various embodiments of the present application are, for example, Figure 2 The network equipment involved, or Figures 3 to 6 Any satellite or satellite ground station involved. The first terminal device involved in each embodiment of the present application is, for example, Figure 2 The first terminal device involved, or Figures 3 to 6 Any terminal device 1 involved. The second terminal device involved in each embodiment of the present application is, for example, Figure 2 The second terminal device involved, or Figures 3 to 6 Any terminal device 2 involved. In addition, if the technical solutions provided by the various embodiments of the present application are applied to other communication systems, the name and / or function of the device may be changed, and the various embodiments of the present application do not limit this.

[0107] Please refer to Figure 7 , which is a schematic diagram of a communication method provided in an embodiment of the present application.

[0108] S701: A network device sends a first RAR message. In the embodiment of the present application, a first terminal device receiving a first RAR message is taken as an example.

[0109] The network device may send the first RAR message by broadcasting or paging. In the embodiment of the present application, the first terminal device receiving the first RAR message is taken as an example. The following is an introduction to the mechanism of the network device sending the first RAR message and the first terminal device receiving the first RAR message under this assumption.

[0110] Exemplarily, the network device may be preconfigured or predefined with multiple random access preamble identifiers, for example, the protocol predefines multiple random access preamble identifiers in the network device. Optionally, each of the multiple random access preambles may include a cyclic prefix (CP) and a data portion (sequence, Seq). In the embodiment of the present application, it is taken as an example that multiple random access preambles include a first random access preamble and a second random access preamble.

[0111] The network device may indicate a random access preamble (such as a first random access preamble) through a first RAR message. For example, the first RAR message carries an identifier of the first random access preamble. In this case, the first RAR message may be regarded as the first RAR message corresponding to the first random access preamble. After the network device sends the first RAR message, the first terminal device determines that the first random access preamble indicated by the first RAR message is the random access preamble adopted by the first terminal device for random access, and the first terminal device determines to select the first RAR message. In this way, the first terminal device may continue to perform the random access process based on the first RAR message.

[0112] The random access preamble code used by the first terminal device for random access may be a random access preamble code used by the first terminal device to initiate random access. The first terminal device determining to select the first RAR message may be understood as the first terminal device determining that the first terminal device is a receiving end of the first RAR message, or may be understood as the first terminal device being a terminal device paged by the network device through the first RAR message.

[0113] The first RAR message may indicate a first TA amount. For example, the first RAR message includes a TAC, and the TAC indicates or includes a first TA amount. Under the assumption that the first terminal device receives the first RAR message, the first TA amount can be used by the network device to determine a first time window, and the first time window is a time window for receiving a first message from the first terminal device. The first message is used by the first terminal device to request to establish a connection with the network device, such as establishing a radio resource control (RRC) connection, and the first message is, for example, Msg3. The first TA amount may be preconfigured or predefined in the network device, or the first TA amount may be determined by the network device. For example, the protocol predefines multiple TA amounts in the network device, and the network device determines a TA amount from the multiple TA amounts as the first TA amount.

[0114] Exemplarily, each TA amount among the multiple TA amounts is associated with an index (or sequence number, or identifier) ​​of a RAR message, and the network device determines the index of the first RAR message, and determines the TA amount corresponding to the index of the first RAR message as the first TA amount.

[0115] Please refer to Table 1 below, which is an example of multiple TA amounts and multiple RAR messages provided in an embodiment of the present application.

[0116] Table 1

[0117]

[0118] As shown in Table 1 above, the network device determines that the index of the first RAR message is 1, and then determines that the first TA amount is 0.66 milliseconds (ms), or 1282T s . T s It can be the basic time unit for NR. Alternatively, if the index of the first RAR message is 2, the first TA amount is determined to be 0.41 ms, or 801T. s Alternatively, if the index of the first RAR message is 3, the first TA amount is determined to be 0.16 ms, or 320 T. s , and so on. Among them, the start time of sending the RAR message with index 3 differs from the start time of sending the RAR message with index 4 by one or more time slots. The start time of sending the RAR message with index 6 differs from the start time of sending the RAR message with index 7 by one or more time slots.

[0119] Optionally, the first TA amount is less than or equal to a third duration. The third duration is, for example, a maximum value of an adjustable TA amount. For example, in an LTE system, the third duration is, for example, 0.67 ms.

[0120] Among them, T s=1 / (15k*2048)=1 / 30720000s=32.55208 nanoseconds (ns). In this optional manner, the first TA amount may be 0.66ms, 0.41ms or 0.16ms. In other words, the first TA amount may be 1282T s 、801T s or 320T s .

[0121] Alternatively, in the NR system, the third duration is, for example, 3846T c or 957T c . T C =T s / 64, Tc can be the basic time unit for LTE. When the subcarrier spacing corresponding to the NR system is 15 kHz, the first TA amount can be 3846Tc, 3365Tc c 、2884T c 、2403T c , 1922T c 、1441T c 、960T c 、479T c 、1919T c 、1438T c 、957T c or 476T c .

[0122] When the subcarrier spacing corresponding to the NR system is 30Khz, the first TA amount can be 3846T c 、2885T c , 1924T c , 2T c 、961T c ,0T c 、959T c or 1918T c Alternatively, the first TA amount may be 957T c 、1916T c 、955T c 、1914T c 、953T c 、1912T c or 951T c .

[0123] Optionally, after receiving the RAR message, the terminal device may send a fifth message to the network device. The fifth message is, for example, Msg3. In the embodiment of the present application, the fifth message sent by the first terminal device may be, for example, the first message described below, and the fifth message sent by the second terminal device may be, for example, the second message described below. The starting time unit for the terminal device to send the fifth message is different, and the value of the first TA amount may be different. In other words, the first TA amount is associated with the starting time unit for the terminal device to send the fifth message.

[0124] Please refer to Table 2 below, which is an example of a starting time unit corresponding to multiple TA amounts, multiple RAR messages, and multiple fifth messages provided in an embodiment of the present application. In Table 2, the subcarrier spacing corresponding to the NR system is 30Khz for example.

[0125] Table 2

[0126]

[0127] As shown in Table 2 above, when the starting time unit of the terminal device sending the fifth message is time unit (n+3), the index of the first RAR message is 1, then the first TA amount is 3846Tc, or the index of the first RAR message is 2, then the first TA amount is 3365Tc, or the index of the first RAR message is 3, then the first TA amount is 2884Tc, or the index of the first RAR message is 4, then the first TA amount is 2430Tc, or the index of the first RAR message is 5, then the first TA amount is 1922Tc, or the index of the first RAR message is 6, then the first TA amount is 1441Tc, or the index of the first RAR message is 7, then the first TA amount is 960Tc, or the index of the first RAR message is 8, then the first TA amount is 479Tc. Time unit (n+3) can indicate that the number of the time unit is (n+3). If the time slots are numbered starting from 0, then a time unit of (n+3) indicates the (n+4)th time slot.

[0128] When the starting time unit of the terminal device sending the fifth message is time unit (n+4), the index of the first RAR message is 9, and the first TA amount is 1919T c , or the index of the first RAR message is 10, then the first TA amount is 1438Tc, or the index of the first RAR message is 11, then the first TA amount is 957T c , or the index of the first RAR message is 12, then the first TA amount is 476T c .

[0129] Please refer to Table 3 below, which is another example of the start time units corresponding to multiple TA amounts, multiple RAR messages, and multiple fifth messages provided in an embodiment of the present application.

[0130] Table 3

[0131]

[0132]

[0133] As shown in Table 3 above, when the starting time unit of the terminal device sending the fifth message is time unit (n+4), the index of the first RAR message is 1, and the first TA amount is 3846T c , or the index of the first RAR message is 2, then the first TA amount is 2885T c , or the index of the first RAR message is 3, then the first TA amount is 1924T c , or the index of the first RAR message is 4, then the first TA amount is 963T c , or the index of the first RAR message is 5, then the first TA amount is 2T c , or the index of the first RAR message is 6, then the first TA amount is 961T c , or the index of the first RAR message is 7, then the first TA amount is 0Tc, or the index of the first RAR message is 8, then the first TA amount is 959T c , or the index of the first RAR message is 9, then the first TA amount is 1918T c , or the index of the first RAR message is 10, then the first TA amount is 957T c , or the index of the first RAR message is 11, then the first TA amount is 1916T c , or the index of the first RAR message is 12, then the first TA amount is 955T c , or the index of the first RAR message is 13, then the first TA amount is 1914T c , or the index of the first RAR message is 14, then the first TA amount is 953T c .

[0134] When the starting time unit of the terminal device sending the fifth message is time unit (n+5), the index of the first RAR message is 15, and the first TA amount is 1912T. c When the starting time unit of the terminal device sending the first RAR message is n+6, the index of the first RAR message is 16, and the first TA amount is 951T. c .

[0135] Since the first RAR message indicates the first TA amount, the first terminal device can determine the first TA amount according to the received first RAR message.

[0136] S702: The first terminal device sends a first random access preamble to the network device. Correspondingly, the network device receives the first random access preamble from the first terminal device.

[0137] Optionally, the first random access preamble may be carried in Msg1, and the first terminal device sending Msg1 to the network device is equivalent to sending the first random access preamble. After the network device accesses the first random access preamble, it is determined that the first RAR message is received by the first terminal device.

[0138] The network device may first send the first RAR message, and then receive the first random access preamble from the first terminal device. In other words, the network device sends the first RAR message before receiving the first random access preamble from the first terminal device. For the first terminal device, the first terminal device may first send the first random access preamble to the network device, and then receive the first RAR message from the network device.

[0139] S703: The network device sends a second RAR message.

[0140] In the embodiment of the present application, the second terminal device receiving the second RAR message is taken as an example. Exemplarily, the network device may also send the second RAR message by broadcasting or paging. The mechanism of the network device sending the second RAR message and the second terminal device receiving the second RAR message can refer to the content of the network device sending the first RAR message and the first terminal device receiving the first RAR message in the previous text, which will not be listed here.

[0141] The second RAR message may indicate a second TA amount. For example, the second RAR message includes a TAC, and the TAC carries the second TA amount. Under the assumption that the second terminal device receives the second RAR message, the second TA amount can be used by the network device to determine a second time window, and the second time window is a time window for receiving a second message from the second terminal device. The second message is used for the first terminal device to request to establish a connection with the network device, such as establishing an RRC connection, and the second message is, for example, Msg3. The second TA amount may be preconfigured or predefined in the network device, or the second TA amount may be determined by the network device. For example, multiple TA amounts are preconfigured or predefined in the network device, and the network device determines a TA amount from the multiple TA amounts as the second TA amount. Among them, the way in which the network device determines the second TA amount may refer to the way in which the network device determines the first TA amount in the previous text.

[0142] In a possible implementation manner, the first TA amount and the second TA amount satisfy the following condition 1 or condition 2. Condition 1 and condition 2 are respectively introduced below.

[0143] Condition 1: The difference between the first TA amount and the second TA amount is greater than or equal to the first value.

[0144] The first value is the maximum value of the difference in round-trip delay between the network device and any two terminal devices, respectively, and the any two terminal devices are any two terminals within the coverage of at least one beam of the network device. The at least one beam may include one or more beams. The coverage of at least one beam may also be regarded as the coverage of one cell or multiple cells, or as the coverage of one or more synchronization signals. The synchronization signal is, for example, a synchronization signal and a physical broadcast channel block (SSB). The first value may be preconfigured or predefined in the network device, or determined by the network device itself.

[0145] Exemplarily, the difference in round-trip delay between the network device and any two terminal devices is a third value. There may be multiple third values ​​corresponding to the coverage range of at least one beam of the network device, and the maximum value of the multiple third values ​​is the first value.

[0146] For example, the network device is a satellite, at least one beam is a beam, the radius of the beam is 45 kilometers (km), the maximum elevation angle of any terminal device is 30 degrees (°), and the orbital altitude of the network device is 600km, so the first value in the beam is 0.25ms.

[0147] Please refer to Figure 8 , which is a schematic diagram of the round-trip delay between a network device and a terminal device provided in an embodiment of the present application. Figure 8 In the example, the terminal device is a UE, the network device is a satellite, and the coverage range of a beam of the satellite includes three UEs: UE1, UE2 and UE3.

[0148] like Figure 8 As shown, the round-trip delays between the satellite and UE1, UE2 and UE3 are 5.4ms, 5.5ms and 5.26ms respectively. Accordingly, the multiple third values ​​include (5.5ms-5.4ms)=0.1ms, (5.4ms-5.26ms)=0.14ms and (5.5ms-5.26ms)=0.24ms. Accordingly, the first value is the maximum value among the multiple third values, that is, 0.24ms.

[0149] Optionally, if the first RAR message and the second RAR message are two adjacent RAR messages, then the difference between the first TA amount and the second TA amount may be equal to the first value. Two adjacent RAR messages refer to two adjacent RAR messages sent by the network device within the same time unit.

[0150] For example, please continue to refer to any table in Table 1 to Table 3 above, the TA amounts corresponding to any two adjacent RAR messages differ by a first value (ie, 0.25 ms).

[0151] Condition 2: The difference between the first TA amount and the second TA amount is greater than or equal to the second value.

[0152] The second value is the difference between the first value and the first threshold. The first threshold may be preconfigured or predefined in the network device, or determined by the network device itself. The first threshold may be one of the following A1 to A2.

[0153] A1. The first threshold is zero. In this case, the difference between the first TA amount and the second TA amount is equal to the first value.

[0154] A2. The first threshold is determined according to the length of the cyclic prefix of some or all of the M time units. Alternatively, it can be described as that the first threshold is related to (or corresponds to) the length of the cyclic prefix of some or all of the M time units. M is an integer greater than 1.

[0155] The M time units may be time domain resources for the network device to receive the first message, in other words, the network device receives the first message over the M time units. Alternatively, the M time units may be time domain resources for the network device to receive the second message, in other words, the network device receives the second message over the M time units. Alternatively, the M time units may be a collection of time domain resources for the network device to receive the first message and the second message, in other words, the network device receives the first message and the second message over these M time units.

[0156] For example, taking the time unit as a time slot, the network device receives the first message on time slot 1 and time slot 2, and receives the second message on time slot 3 and time slot 4, then the M time units may include time slot 1, time slot 2, time slot 3 and time slot 4.

[0157] The following introduces possible implementation forms of the first threshold under A2.

[0158] A2-1. The first threshold is the length of a cyclic prefix (such as called the first cyclic prefix) among the cyclic prefixes of the M time units.

[0159] One of the M time units includes one or more cyclic prefixes, so the cyclic prefixes of the M time units include multiple cyclic prefixes. In order to simplify the description, the cyclic prefixes of the M time units are simplified as multiple cyclic prefixes below. For example, the first cyclic prefix is ​​the cyclic prefix with the largest length among the multiple cyclic prefixes. Or, the first cyclic prefix is ​​the cyclic prefix with the smallest length among the multiple cyclic prefixes. Or, the first cyclic prefix is ​​any cyclic prefix among the multiple cyclic prefixes. Or, the first cyclic prefix is ​​the Kth cyclic prefix among the multiple cyclic prefixes. K is preconfigured or predefined in the network device, and K is a positive integer.

[0160] A2-2. The first threshold is an average value of lengths of multiple cyclic prefixes.

[0161] A2-3. The first threshold is an average value of lengths of some cyclic prefixes among the multiple cyclic prefixes.

[0162] Since the second RAR message indicates the second TA amount, the second terminal device can determine the second TA amount according to the received second RAR message.

[0163] S704: The second terminal device sends a second random access preamble to the network device. Correspondingly, the network device receives the second random access preamble from the second terminal device.

[0164] Optionally, the second random access preamble may be carried in Msg1, and the second terminal device sending Msg1 to the network device is equivalent to sending the second random access preamble. After the network device accesses the second random access preamble, it is determined that the second RAR message is received by the second terminal device.

[0165] The network device may first send the second RAR message, and then receive the second random access preamble from the second terminal device. In other words, the network device sends the second RAR message before receiving the second random access preamble from the second terminal device. For the second terminal device, the second terminal device may first send the second random access preamble to the network device, and then receive the second RAR message from the network device.

[0166] S705: The first terminal device sends a first message to the network device. Correspondingly, the network device receives the first message from the first terminal device.

[0167] In a possible implementation, S705 may include S705a and S705b, wherein S705a is: the first terminal device sends a first message to the network device within the third time window, and S705b is: the network device receives the first message within the first time window.

[0168] For example, the starting time unit of the third time window is: n+X-TA1, where n is the last time unit at which the first terminal device receives the first RAR message, and TA1 represents the first TA amount.

[0169] In the LTE system, X is 6. Or, in the NR system, X is k2+Δ+2 u *K cell，offset . K cell，offset K is the scheduling offset used for the timing relationships that are modified for NTN. cell，offset It can be a configuration of the network device to the first terminal device, for example, K cell，offset The network device may configure the first terminal device through the cell-specific offset K (CellSpecific_Koffset). Alternatively, if the network device does not configure K for the first terminal device cell，offset , then K cell，offset It can be 0. k2 and Δ can be preconfigured or predefined in the first terminal device.

[0170] Please refer to Table 4, which shows possible values ​​of k2 when the time domain resource of the physical uplink shared channel (PUSCH) is a normal cyclic prefix.

[0171] Table 4

[0172]

[0173] Wherein, S represents the starting symbol of PUSCH, and L represents the number (or length) of symbols occupied by PUSCH.

[0174] Please refer to Table 5, which shows possible values ​​of k2 when the time domain resource of the PUSCH is a normal cyclic prefix.

[0175] Table 5

[0176]

[0177]

[0178] The value of j can be found in Table 6 below.

[0179] Table 6

[0180] <![CDATA[u PUSCH ]]> j 0 1 1 1 2 2 3 3 4 11 5 12

[0181] Among them, uPUSCH Indicates the PUSCH subcarrier spacing configuration. The value of Δ can be referred to as shown in Table 7 below.

[0182] Table 7

[0183] <![CDATA[u PUSCH ]]> Δ 0 2 1 3 2 4 3 6 4 24 5 48

[0184] In combination with the contents of Tables 4 to 7 above, it can be seen that, taking the subcarrier spacing of 15KHz and the PUSCH mapping type of PUSCH mapping TypeA as an example, the starting time unit of the third time window may be n+3, n+4, n+5 or n+6 as an example; taking the subcarrier spacing of 30KHz and the PUSCH mapping type of PUSCH mapping TypeA as an example, the starting time unit of the third time window may be n+4, n+5, n+6 or n+7.

[0185] The starting time unit of the first time window may be equal to the starting time unit of the third time window. Alternatively, the starting time unit of the first time window is the result of adding the fourth duration to the starting time unit of the third time window.

[0186] When the starting time unit of the first time window is the result of adding the fourth duration to the starting time unit of the third time window, the network device may determine the third time window in the same manner as the first terminal device determines the third time window, and determine the first time window based on the third time window. The fourth duration may be preconfigured or predefined in the network device.

[0187] S706: The second terminal device sends a second message to the network device. Correspondingly, the network device receives the second message from the second terminal device.

[0188] In a possible implementation, S706 may include S706a and S706b, wherein S706a is: the second terminal device sends a second message to the network device within the fourth time window, and S706b is: the network device receives the second message within the second time window.

[0189] The second terminal device may also determine a fourth time window based on the second TA amount. The method for determining the fourth time window may refer to the method for determining the third time window by the first terminal device in the foregoing text. In addition, the network device may determine the second time window, and the method for determining the second time window may refer to the content of determining the first time window by the network device in the foregoing text.

[0190] In the embodiment of the present application, the duration of overlap between the second time window and the first time window is less than or equal to the first threshold.

[0191] If the first threshold is 0, the second time window and the first time window do not overlap at all, or it can be described as that the second time window and the first time window do not overlap. Alternatively, if the first threshold is greater than 0, the second time window and the first time window overlap, but the overlapping duration is less than the first threshold. For example, if the first threshold is 4.7 microseconds (μs), the overlapping duration of the first time window and the second time window can be 2μs or 4.7μs, etc.

[0192] In the case where the conditions satisfied by the first TA amount and the second TA amount are different, the relationship between the second time window and the first time window is also different, as illustrated below with an example.

[0193] If the first TA amount and the second TA amount satisfy the above condition 1 (i.e., the difference between the first TA amount and the second TA amount is greater than or equal to the first value), the first time window and the second time window may not overlap at all. For example, the first time window is the first time unit, and the second time window is the third time unit.

[0194] If the first TA amount and the second TA amount satisfy the above condition 2 (ie, the difference between the first TA amount and the second TA amount is greater than or equal to the second value), then the first threshold is different, and the relationship between the second time window and the first time window is also different, which is explained below.

[0195] B1. The first threshold is the case shown in A1 above, that is, the first threshold is zero, which means that the difference between the first TA amount and the second TA amount is equal to the first value, and the first time window and the second time window may not overlap at all.

[0196] B2. The first threshold is the situation shown in A2 above, that is, the first threshold is determined according to the length of the cyclic prefix of some or all of the M time units, which means that the difference between the first TA amount and the second TA amount is less than or equal to the second value, then the first time window and the second time window may partially overlap, but the duration of the overlap is less than or equal to the first threshold.

[0197] B2-1, the first threshold is the situation of A2-1 above, that is, the first threshold is the length of the first cyclic prefix, then the first time window and the second time window may partially overlap, and the duration of the overlap between the first time window and the second time window is less than or equal to the length of the first cyclic prefix.

[0198] B2-2, the first threshold is the case of A2-2 above, that is, the first threshold is the average length of multiple cyclic prefixes, then the first time window and the second time window may partially overlap, and the overlapping duration of the first time window and the second time window is less than or equal to the average length of multiple cyclic prefixes.

[0199] B2-3, the first threshold is the case of A2-3 above, that is, the first threshold is the average length of some cyclic prefixes among multiple cyclic prefixes, then the first time window and the second time window may partially overlap, and the duration of the overlap between the first time window and the second time window is less than or equal to the average length of some cyclic prefixes among the multiple cyclic prefixes.

[0200] For example, see Fig. 9 , is a schematic diagram of a random access process provided by an embodiment of the present application. Fig. 9 The difference between TA1 and TA2 is greater than or equal to the first value as an example for illustration.

[0201] like Fig. 9 As shown, the first terminal device sends a first message in the third time window w3, and the starting time unit of the third time window w3 is the time unit (n+X-TA1). The second terminal device sends a second message in the fourth time window w4. The starting time unit of the fourth time window w4 is the time unit (n+X-TA2), and TA2 represents the second TA quantity. In this way, the difference between the starting times of the third time window and the fourth time window is greater than or equal to (TA1-TA2-first value) and less than or equal to (TA1-TA2). And because the difference between TA1 and TA2 is greater than or equal to the first value, there is no overlap between the first time window w1 for the network device to receive the first message and the second time window w2 for receiving the second message, thereby avoiding mutual interference between the first message and the second message. As shown Fig. 9 As shown, there is no overlap between the first time window and the second time window. The starting time involved in each embodiment of the present application may also be referred to as the start time.

[0202] Or for example, see Fig.10 , is a schematic diagram of a random access process provided by an embodiment of the present application. Fig.10 The difference between TA1 and TA2 is greater than or equal to the second value as an example for illustration.

[0203] like Fig.10 As shown, the first terminal device sends the first message in the third time window w3, and the starting time unit of the third time window w3 is the time unit (n+X-TA1). The second terminal device sends the second message in the fourth time window w4. The starting time unit of the fourth time window w4 is the time unit (n+X-TA2). In this way, the difference between the starting time of the third time window and the fourth time window is greater than or equal to (TA1-TA2-first value) and less than or equal to (TA1-TA2). Since the difference between TA1 and TA2 is greater than or equal to the second value, the overlapping duration c1 between the first time window w1 and the second time window w2 is less than or equal to the first threshold value. In this way, the network device can still successfully receive the first message and the second message, and the mutual interference between the first message and the second message is also reduced.

[0204] S707, the network device sends a third message to the first terminal device. Correspondingly, the first terminal device receives the third message from the network device. The third message is used to indicate contention solution. The third message is, for example, Msg4.

[0205] S708: The network device sends a fourth message to the second terminal device. Correspondingly, the second terminal device receives the fourth message from the network device. The fourth message is used to indicate contention resolution. For example, the fourth message is Msg4.

[0206] S707-S708 are optional steps. Figure 7 Indicated by dotted line.

[0207] It should be understood that in Figure 7 The illustrated embodiment takes two terminal devices, a first terminal device and a second terminal device, as examples. In fact, the communication method provided in the embodiment of the present application can be applicable to three or more terminal devices, and the embodiment of the present application does not limit this.

[0208] In the embodiment of the present application, before receiving the random access preamble from the terminal device, the network device can indicate the timing advance to the terminal device through a random access response message. For different terminal devices, the network device can indicate different timing advances respectively, staggering the time windows for the network device to receive messages (such as Msg3) from different terminal devices, thereby reducing message interference from different terminal devices, improving the success rate of the network device receiving messages from the terminal device, and thus improving the success rate of the terminal device accessing the network device. In addition, since the network device indicates the timing advances of different terminal devices respectively, the network device has a high flexibility in indicating the timing advance, which will not affect the number of random response messages sent by the network device within a certain period of time, so that the network device can access more terminal devices within a fixed period of time, and more terminal devices can access the network device in a timely manner, thereby improving the efficiency of terminal devices accessing the network device.

[0209] Under another random access mechanism, the base station may first receive a random access preamble from the terminal device, and estimate the round-trip delay between the base station and the terminal device based on the random access preamble. The base station performs a modulo operation on the round-trip delay to obtain a remainder, and uses the remainder as the timing advance. The base station may indicate the TA amount to the terminal device through an RAR message, so that the terminal device can perform delay compensation based on the TA amount, thereby enabling the base station to align the start time of Msg3 received from the terminal device with the start time of a certain time slot. However, in this way, the start time of the base station receiving the Msg3 of the terminal device is fixed, and the flexibility is poor.

[0210] For example, see Fig.11, which is the time window for a network device under another random access mechanism to receive Msg3 from different UEs. If the round-trip delay between UE1 and the network device is 4.5ms, the network device may indicate to UE1 that the TA amount is 0.5ms. The round-trip delay between UE2 and the network device is 5.4ms, the base station may indicate to UE2 that the TA amount is 0.4ms. Then the starting time for the base station to receive Msg3 from UE1 is the starting time of the fourth time slot (such as the 4th ms), and the starting time for receiving Msg3 from UE2 is the starting time of the fifth time slot (such as the 5th ms).

[0211] In view of this, an embodiment of the present application provides a communication scheme, in which a network device can flexibly indicate a first timing advance to a first terminal device and / or indicate a second timing advance to a second terminal device. Furthermore, based on the first timing advance, the network device determines that a first time window for receiving a first message (such as Msg3) from the first terminal device does not have to be aligned with the start time of the time unit, and a second time window for receiving a second message (such as Msg3) from the second terminal device determined based on the second timing advance does not have to be aligned with the start time of the time unit, thereby improving the flexibility of the network device in receiving time windows for messages (such as Msg3) from different terminals.

[0212] Please refer to Fig.12 , which is a schematic diagram of a communication method provided in an embodiment of the present application.

[0213] S1201: A first terminal device sends a first random access preamble to a network device. Correspondingly, the network device receives the first random access preamble from the first terminal device.

[0214] For example, the first random access preamble can be carried in Msg1, and the first terminal device sending Msg1 to the network device is equivalent to sending the first random access preamble. The first random access preamble is used to indicate that the first terminal device initiates random access and is used to determine (or estimate) the first round-trip delay between the first terminal device and the network device.

[0215] S1202: The network device sends a first TA amount to the first terminal device. Correspondingly, the first terminal device receives the first TA amount from the network device.

[0216] Exemplarily, the network device may determine the first TA amount according to the first round trip delay. In a possible implementation, the network device may determine the first round trip delay according to the moment of receiving the first random access preamble and the moment of sending the first random access preamble by the first terminal device. The moment when the first terminal device sends the first random access preamble may be preconfigured or predefined in the network device, for example, preconfigured in the network device through a protocol.

[0217] The network device may perform a modulus operation on the first round trip delay to obtain a first remainder, and use the result of subtracting the first duration from the first remainder as the first timing advance. The first duration may be preconfigured or predefined in the network device, or determined by the network device itself.

[0218] Optionally, before the network device subtracts the first duration from the first remainder, it can be determined whether the first remainder is greater than the second duration. If the first remainder is greater than the second duration, the first remainder is subtracted from the first duration. If the first remainder is less than or equal to the second duration, the first remainder can be directly used as the first timing advance. The first timing advance may be less than or equal to the second duration. The second duration may be preconfigured or predefined in the network device, or determined by the network device itself, and the second duration is less than or equal to the maximum value of the timing advance that can be adjusted by the first terminal device. For example, the first duration is 0.5ms or 0.34ms, and the second duration is, for example, 0.67ms, 0.5ms or 0.34ms.

[0219] For example, the first duration is 0.5 ms and the second duration is 0.67 ms. If the first remainder re_ms is greater than 0.67, the first TA amount TA1 = re_ms - 0.5 ms. If the first remainder re_ms is less than or equal to 0.67, TA1 = re_ms.

[0220] Alternatively, the first duration is 0.5 ms and the second duration is 0.5 ms, if the first remainder re_ms is greater than 0.5, then TA1 = re_ms - 0.5 ms. If the first remainder re_ms is less than or equal to 0.5, then TA1 = re_ms.

[0221] Alternatively, the first duration is 0.5 ms and the second duration is 0.34 ms, if the first remainder re_ms is greater than 0.34, then TA1 = re_ms - 0.5 ms. If the first remainder re_ms is less than or equal to 0.34, then TA1 = re_ms.

[0222] Alternatively, the first duration is 0.34 ms and the second duration is 0.34 ms, if the first remainder re_ms is greater than 0.34, then TA1 = re_ms - 0.34 ms. If the first remainder re_ms is less than or equal to 0.34, then TA1 = re_ms.

[0223] In a possible implementation, the first terminal device may carry the first TA amount in a first RAR message, and send the first RAR message to the network device, which is equivalent to sending the first TA amount to the network device.

[0224] S1203: The second terminal device sends a second random access preamble to the network device. Correspondingly, the network device receives the second random access preamble from the second terminal device.

[0225] For example, the second random access preamble can be carried in Msg1, and the second terminal device sending Msg1 to the network device is equivalent to sending the second random access preamble. The second random access preamble is used to indicate that the second terminal device initiates random access and is used to estimate the second round trip delay between the second terminal device and the network device.

[0226] S1204: The network device sends a second TA amount to the second terminal device. Correspondingly, the second terminal device receives the second TA amount from the network device.

[0227] Exemplarily, the network device may determine the first TA amount according to the second round-trip delay. The content of the network device determining the second round-trip delay may refer to the content of determining the first round-trip delay in the foregoing text, and the process of determining the second TA amount according to the second round-trip delay may refer to the content of determining the first TA amount according to the first round-trip delay in the foregoing text.

[0228] In a possible implementation, the second terminal device may carry the second TA amount in a second RAR message, and send the second RAR message to the network device, which is equivalent to sending the second TA amount to the network device.

[0229] S1205. The first terminal device sends a first message to the network device. Correspondingly, the network device receives the first message from the first terminal device. The first message is used to request to establish a connection with the network device, for example, to establish an RRC connection.

[0230] Exemplarily, S1205 includes S1205a and S1205b, wherein S1205a is: the first terminal device sends the first message within the third time window, and S1205b is: the network device receives the first message within the first time window.

[0231] In the embodiment of the present application, the start time of the first time window is different from the start time of the first time unit (or is called misalignment). In other words, the start time of the first time window is the non-start time of the first time unit. The first time unit may be predefined by a protocol or preconfigured in the network device, for example, and the first time unit is the time unit where the start time of the network device receiving the first message is located.

[0232] The starting time unit of the third time window is, for example, the time unit (n1+X-TA1). Where n1 represents the last time unit of the first terminal device receiving the first TA amount, and the value of X can refer to the above Figure 7If the first TA amount is carried in the first RAR message, then n1 is the same as the previous Figure 7 The n in is the same.

[0233] The network device may determine the first time window according to the first TA amount. Exemplarily, the difference between the start time of the first time window and the start time of the third time window is greater than or equal to the first round-trip delay. For example, the start time unit of the first time window is: n1+X-TA1+delay1. Wherein, delay1 represents the first round-trip delay.

[0234] S1206: The second terminal device sends a second message to the network device. Correspondingly, the network device receives the second message from the second terminal device. The second message is used to request to establish a connection with the network device, for example, to establish an RRC connection.

[0235] Exemplarily, S1206 includes S1206a and S1206b, wherein S1206a is: the second terminal device sends the second message within the fourth time window, and S1206b is: the network device receives the second message within the second time window.

[0236] In the embodiment of the present application, the start time of the second time window is different from the start time of the second time unit (or is called misalignment). In other words, the start time of the second time window is the non-start time of the second time unit. The second time unit may be predefined by a protocol or preconfigured in the network device, for example, and the second time unit is the time unit where the start time of the network device receiving the second message is located.

[0237] The starting time unit of the fourth time window is, for example, the time unit (n2+X-TA2). TA2 represents the second TA amount, n2 represents the last time unit of the second terminal device receiving the second TA amount, and the value of X can refer to the above Figure 7 The content of X.

[0238] The network device may determine the second time window according to the second TA amount. Exemplarily, the difference between the start time of the second time window and the start time of the fourth time window is greater than or equal to the first round-trip delay. For example, the start time unit of the second time window is the time unit (n2+X-TA2+delay2). Wherein delay2 represents the second round-trip delay.

[0239] In an embodiment of the present application, the network device determines TA1 and TA2 in the same manner, and the process of the network device determining the first time window and the second time window is similar, so that the start time of the first time window and the start time of the second time window can be separated by N time units, where N is a natural number.

[0240] S1207: The network device sends a third message to the first terminal device. Correspondingly, the first terminal device receives the third message from the network device. The third message is used to indicate contention resolution. The third message is, for example, Msg4.

[0241] S1208: The network device sends a fourth message to the second terminal device. Correspondingly, the second terminal device receives the fourth message from the network device. The fourth message is used to indicate contention resolution. For example, the fourth message is Msg4.

[0242] S1207-1208 are optional steps. Fig.12 Indicated by dotted line.

[0243] The embodiment of the present application takes the first time window and the second time window as an example, where the interval between N time units is assuming that the network device may receive the first message and the second message in a space division or frequency division manner. In this case, the first terminal device and the second terminal device may be regarded as a terminal device group (referred to as a first terminal device group) for the network device. When both the first terminal device and the second terminal device are UEs, the first terminal device and the second terminal device may be regarded as a UE group (referred to as a first UE group).

[0244] S1209: The third terminal device sends a third random access preamble to the network device. Correspondingly, the network device receives the third random access preamble from the third terminal device.

[0245] For example, the third random access preamble may be carried in Msg1, and the third terminal device sending Msg1 to the network device is equivalent to sending the third random access preamble. The third random access preamble is used to indicate that the third terminal device initiates random access, and is used to determine (or estimate) the third round-trip delay between the third terminal device and the network device.

[0246] S1210: The network device sends a third TA amount to the third terminal device. Correspondingly, the third terminal device receives the third TA amount from the network device.

[0247] Exemplarily, the network device may determine the third TA amount according to the third round trip delay. In a possible implementation, the network device may determine the third round trip delay according to the moment of receiving the third random access preamble and the moment of sending the third random access preamble by the third terminal device. The moment when the third terminal device sends the third random access preamble may be preconfigured or predefined in the network device, for example, preconfigured in the network device through a protocol.

[0248] The network device may perform a modulus operation on the third round trip delay to obtain a third remainder. In the embodiment of the present application, the third remainder is described as being less than the second duration. In this case, the network device may determine the third remainder as the third TA amount.

[0249] S1211: The fourth terminal device sends a fourth random access preamble to the network device. Correspondingly, the network device receives the fourth random access preamble from the fourth terminal device.

[0250] For example, the fourth random access preamble may be carried in Msg1, and the fourth terminal device sending Msg1 to the network device is equivalent to sending the fourth random access preamble. The fourth random access preamble is used to indicate that the fourth terminal device initiates random access and is used to determine (or estimate) the fourth round-trip delay between the fourth terminal device and the network device.

[0251] S1212: The network device sends a fourth TA amount to the fourth terminal device. Correspondingly, the fourth terminal device receives the fourth TA amount from the network device.

[0252] Exemplarily, the network device may determine the fourth TA amount according to the fourth round trip delay. In a possible implementation, the network device may determine the fourth round trip delay according to the moment of receiving the fourth random access preamble and the moment of sending the fourth random access preamble by the fourth terminal device. The moment when the fourth terminal device sends the fourth random access preamble may be preconfigured or predefined in the network device, for example, preconfigured in the network device through a protocol.

[0253] The network device may perform a modulus operation on the fourth round trip delay to obtain a fourth remainder. In the embodiment of the present application, the fourth remainder is described as being less than the second duration. In this case, the network device may determine the fourth remainder as the fourth TA amount.

[0254] S1213: The third terminal device sends a sixth message to the network device. Correspondingly, the network device receives the sixth message from the third terminal device. The sixth message is used to request to establish a connection with the network device, for example, to establish an RRC connection.

[0255] Exemplarily, S1213 includes S1213a and S1213b, wherein S1213a includes: the third terminal device sends the sixth message within the fifth time window, and S1213b includes: the network device receives the sixth message within the sixth time window.

[0256] Among them, the way in which the third terminal device determines the fifth time window can refer to the content of the first terminal device determining the third time window in S1205a above, and the way in which the network device determines the sixth time window can refer to the content of the network device determining the first time window above, which are not listed here.

[0257] S1214: The fourth terminal device sends a seventh message to the network device. Correspondingly, the network device receives the seventh message from the fourth terminal device. The seventh message is used to request to establish a connection with the network device, for example, to establish an RRC connection.

[0258] Exemplarily, S1214 includes S1214a and S1214b, wherein S1214a includes: the fourth terminal device sends the seventh message within the seventh time window, and S1214b includes: the network device receives the seventh message within the eighth time window.

[0259] Among them, the way in which the fourth terminal device determines the seventh time window can refer to the content of the first terminal device determining the third time window in S1205a above, and the way in which the network device determines the eighth time window can refer to the content of the network device determining the first time window above, which are not listed here.

[0260] Since the network device uses the third remainder as the third TA amount and the fourth remainder as the fourth TA amount, this enables the sixth time window to be aligned with the starting time of the third time unit, the seventh time window to be aligned with the starting time of the fourth time window, and the starting time of the sixth time window differs from the starting time of the eighth time window by M time units, where M is a natural number. The third time unit may be predefined or preconfigured in the network device by a protocol, for example, and the third time unit is, for example, a time unit at which the network device receives the starting time of the sixth message. The fourth time unit may be predefined or preconfigured in the network device by a protocol, for example, and the fourth time unit is, for example, a time unit at which the network device receives the starting time of the seventh message. In this way, the network device may receive the sixth message and the seventh message in a space division or frequency division manner. In this case, the third terminal device and the fourth terminal device may be regarded as a terminal device group (which may be referred to as a second terminal device group) for the network device. In the case where the third terminal device and the fourth terminal device are both UEs, the third terminal device and the fourth terminal device may be regarded as a UE group (which may be referred to as a second UE group).

[0261] S1215. The network device sends an eighth message to the third terminal device. Correspondingly, the third terminal device receives the eighth message from the network device. The eighth message is used to indicate contention resolution. The eighth message is, for example, Msg4.

[0262] S1216: The network device sends a ninth message to the fourth terminal device. Correspondingly, the fourth terminal device receives the ninth message from the network device. The ninth message is used to indicate contention resolution. The ninth message is, for example, Msg4.

[0263] S1209-S1216 illustrate the process of random access of the third terminal device and the fourth terminal device, and S1209-S1216 are all optional steps. Fig.12 Indicated by dotted line.

[0264] It should be understood that in Fig.12 The illustrated embodiment takes four terminal devices, namely a first terminal device, a second terminal device, a third terminal device and a fourth terminal device, as examples. In fact, the communication method provided in the embodiment of the present application can be applicable to two or more terminal devices, and the embodiment of the present application does not limit this.

[0265] Please refer to Fig.13 , is a schematic diagram of a time window for a network device to receive Msg3 of different UEs provided in an embodiment of the present application. Fig.13 In the example, the first terminal device is UE1, the second terminal device is UE2, the third terminal device is UE3, and the fourth terminal device is UE4. In addition, Fig.13 In the example, the first message, the second message, the sixth message and the seventh message are all Msg3, the first duration is 0.5ms, and the second duration is 0.67ms. Fig.13 As shown in the figure, the round-trip delays between UE1, UE2, UE3 and UE4 and the network equipment are 8.9ms, 9.9ms, 5.5ms and 6.5ms respectively. Fig.13 In the figure, the first round-trip delay, the second round-trip delay, the third round-trip delay and the fourth round-trip delay are 8.9ms, 9.9ms, 5.5ms and 6.5ms respectively.

[0266] The network device determines that the remainder corresponding to the first round-trip delay (i.e., the first remainder) is 0.9ms, and then determines that the TA amount corresponding to UE1 (i.e., the first TA amount) is the difference between the first remainder and the first duration, i.e., 0.4ms. Similarly, the network device determines that the remainder corresponding to the second round-trip delay (i.e., the second remainder) is 0.9ms, and then determines that the TA amount corresponding to UE2 (i.e., the second TA amount) is 0.4ms.

[0267] The network device determines that the remainder corresponding to the third round-trip delay (i.e., the third remainder) is 0.5 ms, and the network device determines that the third remainder is less than the second duration, so the network device determines that the TA amount corresponding to UE3 (i.e., the third TA amount) is 0.5 ms. Similarly, the network device determines that the remainder corresponding to the fourth round-trip delay (i.e., the fourth remainder) is 0.5 ms, and the network device determines that the fourth remainder is less than the second duration, so the network device determines that the TA amount corresponding to UE4 (i.e., the fourth TA amount) is 0.5 ms.

[0268] Furthermore, UE1 sends Msg3 0.4ms in advance, UE2 sends Msg3 0.4ms in advance, UE3 sends Msg3 0.5ms in advance, and UE1 sends Msg3 0.5ms in advance. Then the network device receives Msg3 of UE1 at 0.5ms of the time unit corresponding to 6.5ms, receives Msg3 of UE2 at 0.5ms of the time unit corresponding to 7.5ms, receives Msg3 of UE3 at the beginning of the time unit corresponding to 3ms, and receives Msg3 of UE4 at the beginning of the time unit corresponding to 4ms. In this way, the network device is equivalent to treating UE1 and UE2 as the first UE group, and treating UE3 and UE4 as the second UE group. The start time of receiving Msg3 of the first UE group by the network device is the non-start time of the time unit, and the start time of receiving Msg3 of the second UE group is the start time of the time unit. In this way, the network device uses frequency division or space division multiplexing to receive Msg3 of UE1 and UE2 in the first UE group. And, the network device adopts frequency division or space division multiplexing to receive Msg3 of UE3 and UE4 in the second UE group.

[0269] In the embodiment of the present application, the start time of the network device receiving Msg3 does not need to be aligned with the start time of the time unit, which improves the flexibility of the network device receiving Msg3. In addition, the network device can instruct the terminal device to compensate for part of the delay through the TA amount, and the network device will compensate for part of the delay by itself, so as to avoid the situation where the TA amount required to be indicated is too large. On the one hand, it can avoid the situation where the terminal device cannot accurately or successfully compensate for the delay due to the TA amount being too large. On the other hand, it can reduce the number of bits required for the network device to indicate the TA amount, which is conducive to saving the resource overhead of the network device indicating the TA amount. Furthermore, the embodiment of the present application can be applied to scenarios with large round-trip delays between the network device and the terminal device, such as NTN scenarios. In addition, when the remainder corresponding to the round-trip delay is less than or equal to the second duration, the round-trip delay may not be processed, thus reducing the operation of the network device. Further, the network device can divide the terminal devices with a remainder less than or equal to the second duration and the terminal devices with a remainder greater than the second duration into two groups of terminal devices, and then the network device can use frequency division or space division multiplexing to receive messages (such as Msg3) of each terminal device group.

[0270] It is understandable that in order to implement the functions in the above embodiments, the network device and the terminal device include hardware structures and / or software modules corresponding to the execution of each function. It should be easily appreciated by those skilled in the art that, in combination with the units and method steps of each example described in the embodiments disclosed in this application, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application scenario and design constraints of the technical solution.

[0271] Fig.14 and Fig.15 The following is a schematic diagram of the structure of possible communication devices provided in the embodiments of the present application. These communication devices can be used to implement the functions of the terminal device or network device in the above method embodiments, and thus can also achieve the beneficial effects of the above method embodiments. In the embodiments of the present application, the communication device is, for example, Figure 2 The network equipment involved, or Figures 3 to 6 Any satellite or satellite ground station involved, etc.

[0272] like Fig.14 As shown, the communication device 1400 includes a transceiver module 1410 and a processing module 1420. The communication device 1400 is used to implement Figure 7 or Fig.12 The functions of the network device or terminal device in the method embodiment shown in FIG.

[0273] When the communication device 1400 is used to implement Figure 7 When the network device functions in the method embodiment shown, the processing module 1420 can be used to control the transceiver module 1410 to execute steps S701-S706.

[0274] When the communication device 1400 is used to implement Figure 7 When the function of the first terminal device in the method embodiment shown is used, the processing module 1420 can control the transceiver module 1410 to execute S701 to S702, and execute S705a and other steps. Alternatively, when the communication device 1400 is used to implement Figure 7 When the function of the second terminal device in the method embodiment shown is performed, the processing module 1420 can be used to control the transceiver module 1410 to execute S703 to S704, and execute steps such as S706a.

[0275] When the communication device 1400 is used to implement Fig.12 When the network device functions in the method embodiment shown, the processing module 1420 can be used to control the transceiver module 1410 to execute steps S1202, S1204, S1205b and S1206b.

[0276] When the communication device 1400 is used to implement Fig.12 When the function of the first terminal device in the method embodiment shown is performed, the processing module 1420 can be used to control the transceiver module 1410 to execute steps S1202 and S1205a.

[0277] When the communication device 1400 is used to implement Fig.12 When the function of the second terminal device in the method embodiment shown is used, the processing module 1420 can be used to control the transceiver module 1410 to execute steps S1204 and S1206a.

[0278] For more detailed description of the transceiver module 1410 and the processing module 1420, please refer to Figure 7 or Fig.12 The relevant description in the method embodiment shown is directly obtained and will not be repeated here.

[0279] like Fig.15 As shown, the communication device 1500 includes a processor 1510 and an interface circuit 1520. The processor 1510 and the interface circuit 1520 are coupled to each other. It is understood that the interface circuit 1520 can be a transceiver or an input-output interface. Optionally, the communication device 1500 may also include a memory 1530 for storing instructions executed by the processor 1510 or storing input data required by the processor 1510 to execute instructions or storing data generated after the processor 1510 executes instructions.

[0280] When the communication device 1500 is used to implement Figure 7 or Fig.12 When the method is shown, the processor 1510 is used to implement the functions of the above-mentioned processing module 1420, and the interface circuit 1520 is used to implement the functions of the above-mentioned transceiver module 1410.

[0281] When the above-mentioned communication device is a module applied to a network device, the network device module implements the function of the network device in the above-mentioned method embodiment. The module of the network device receives information from other modules in the base station (such as a radio frequency module or an antenna), and the information is sent by the terminal to the network device; or, the module of the network device sends information to other modules in the base station (such as a radio frequency module or an antenna), and the information is sent by the network device to the terminal. The module of the network device here can be a baseband chip of the network device, or it can be a DU or other module, and the DU here can be a DU in O-RAN.

[0282] It is understandable that the processor in the embodiment of the present application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. The general-purpose processor can be a microprocessor or any conventional processor.

[0283] In the embodiment of the present application, another example of a communication providing device includes at least one processor and at least one memory, the at least one processor is coupled to the at least one memory, and the at least one memory is used to store instructions. When the instructions are executed by the at least one processor, the communication device executes the method in the above embodiment. For example, the communication device includes a processor and a memory. Fig.16 As shown, the communication device 1600 includes a processor 1610 and a memory 1620. The processor 1610 and the memory 1620 may be coupled, and the memory 1620 stores instructions. When the instructions stored in the memory 1620 are executed by the processor 1610, the communication device 1600 executes the method executed by the network device in the above embodiment.

[0284] The embodiment of the present application provides a communication system, which includes a first terminal device, a second terminal device and a network device. The first terminal device, the second terminal device and the network device can implement the above Figure 7 or Fig.12 Accordingly, the first terminal device may also execute the communication method described above. Figure 7 or Fig.12 The second terminal device may also perform the functions of the first terminal device mentioned above. Figure 7 or Fig.12 The functions of the second terminal device involved, and the network device can also execute the above Figure 7 or Fig.12 The capabilities of the network devices involved.

[0285] The present application provides a chip system, which includes: a processor and an interface. The processor is used to call and run instructions from the interface. When the processor executes the instructions, any of the above-mentioned communication methods is implemented, such as Figure 7 or Fig.12 The communication method shown.

[0286] The embodiment of the present application provides a computer-readable storage medium, which is used to store computer programs or instructions. When the computer-readable storage medium is executed, any of the above-mentioned communication methods is implemented, such as Figure 7 or Fig.12 The communication method shown.

[0287] The present application embodiment provides a computer program product including instructions, which, when executed on a computer, implements any of the communication methods described above, such as Figure 7 or Fig.12 The communication method shown.

[0288] The method steps in each embodiment of the present application can be implemented in hardware or in software instructions that can be executed by a processor. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, register, hard disk, mobile hard disk, CD-ROM or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. The storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC. In addition, the ASIC can be located in a base station or a terminal. The processor and the storage medium can also be present in a network device or a terminal device as discrete components.

[0289] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instruction is loaded and executed on a computer, the process or function described in the embodiment of the present application is executed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device or other programmable device. The computer program or instruction may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer program or instruction may be transmitted from one website site, computer, server or data center to another website site, computer, server or data center by wired or wireless means. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server, data center, etc. that integrates one or more available media. The available medium may be a magnetic medium, for example, a floppy disk, a hard disk, a tape; it may also be an optical medium, for example, a digital video disc; it may also be a semiconductor medium, for example, a solid-state hard disk. The computer-readable storage medium may be a volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage media.

[0290] In the various embodiments of the present application, unless otherwise specified or provided in a logical conflict, the terms and / or descriptions between the different embodiments are consistent and may be referenced to each other, and the technical features in the different embodiments may be combined to form new embodiments according to their inherent logical relationships.

[0291] In the various embodiments of the present application, the number of nouns, unless otherwise specified, means "singular noun or plural noun", that is, "one or more". "At least one" means one or more, and "plural" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. For example, A / B means: A or B. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c means: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, c can be single or multiple.

[0292] It is understood that the various numerical numbers involved in the various embodiments of the present application are only for the convenience of description and are not used to limit the scope of the embodiments of the present application. The size of the sequence number of the above-mentioned processes does not mean the order of execution, and the execution order of each process should be determined by its function and internal logic.

Claims

1. A communication method, It is characterized in that Applied to a network device, the method comprises: Sending a first random access response message, where the first random access response message indicates a first timing advance, where the first timing advance is used to determine a first time window for receiving a first message, where the first message is used to request establishment of a connection between a first terminal device and the network device; Receiving a first random access preamble from the first terminal device, where the first random access preamble is received after sending the first random access response message; Sending a second random access response message, where the second random access response message indicates a second timing advance, where the second timing advance is used to determine a second time window for receiving a second message, where the second message is used to request establishment of a connection between a second terminal device and the network device, wherein a duration of overlap between the second time window and the first time window is less than or equal to a first threshold; A second random access preamble is received from the second terminal device, wherein the second random access preamble is received after sending the second random access response message.

2. The method according to claim 1, It is characterized in that The difference between the first timing advance and the second timing advance satisfies one of the following: is greater than or equal to the first value; or, is greater than or equal to a second value; The second value is the difference between the first value and the first threshold, the first value is the maximum value of multiple third values, any third value of the multiple third values ​​is the difference in round-trip delay between the network device and two terminal devices respectively, and the two terminal devices are any two terminal devices within the coverage range of at least one beam of the network device.

3. The method according to claim 1 or 2, It is characterized in that The first threshold is zero; or, The first threshold is the length of the first cyclic prefix in the cyclic prefixes of the M time units; or, The first threshold is determined according to the length of the cyclic prefix of M time units; The first message and / or the second message is received in the M time units, and M is an integer greater than 1.

4. The method according to claim 3, It is characterized in that The first cyclic prefix is ​​one of the following: A cyclic prefix of any time unit among the M time units; or The cyclic prefix with the largest length of the M time units; or The M time units have a minimum length of cyclic prefix.

5. The method according to claim 3, It is characterized in that The first threshold is an average value of the lengths of the cyclic prefixes of the M time units.

6. The method according to any one of claims 1 to 5, It is characterized in that The method further comprises: receiving the first message from the first terminal device within the first time window; and / or, Within the second time window, receive the second message from the second terminal device.

7. The method according to any one of claims 1 to 6, It is characterized in that The method further comprises: determining, according to the first timing advance, a third time window for the first terminal device to send the first message, and determining, according to the third time window, the first time window; and / or, A fourth time window for the second terminal device to send the second message is determined based on the second timing advance, and the second time window is determined based on the fourth time window.

8. The method according to any one of claims 1 to 7, It is characterized in that The network device is a network device in a non-terrestrial network.

9. A communication device, It is characterized in that include: A transceiver module and a processing module, wherein the transceiver module is used under the control of the processing module to: Sending a first random access response message, where the first random access response message indicates a first timing advance, where the first timing advance is used to determine a first time window for receiving a first message, where the first message is used to request establishment of a connection between a first terminal device and a network device; Receiving a first random access preamble from the first terminal device, where the first random access preamble is received after sending the first random access response message; Sending a second random access response message, where the second random access response message indicates a second timing advance, where the second timing advance is used to determine a second time window for receiving a second message, where the second message is used to request establishment of a connection between a second terminal device and the network device, wherein a duration of overlap between the second time window and the first time window is less than or equal to a first threshold; A second random access preamble is received from the second terminal device, wherein the second random access preamble is received after sending the second random access response message.

10. The device according to claim 9, It is characterized in that The difference between the first timing advance and the second timing advance satisfies one of the following: is greater than or equal to the first value; or, is greater than or equal to a second value; The second value is the difference between the first value and the first threshold, the first value is the maximum value of multiple third values, any third value of the multiple third values ​​is the difference in round-trip delay between the network device and two terminal devices respectively, and the two terminal devices are any two terminal devices within the coverage range of at least one beam of the network device.

11. The device according to claim 9 or 10, It is characterized in that The first threshold is zero; or, The first threshold is the length of the first cyclic prefix in the cyclic prefixes of the M time units; or, The first threshold is determined according to the length of the cyclic prefix of M time units; The first message and / or the second message is received in the M time units, and M is an integer greater than 1.

12. The device according to claim 11, It is characterized in that The first cyclic prefix is ​​one of the following: A cyclic prefix of any time unit among the M time units; or The cyclic prefix with the largest length of the M time units; or The M time units have a minimum length of cyclic prefix.

13. The device according to claim 11, It is characterized in that The first threshold is an average value of the lengths of the cyclic prefixes of the M time units.

14. The device according to any one of claims 9 to 13, It is characterized in that The transceiver module is used under the control of the processing module to: receiving the first message from the first terminal device within the first time window; and / or, Within the second time window, receive the second message from the second terminal device.

15. The device according to any one of claims 9 to 13, It is characterized in that The processing module is also used for: determining, according to the first timing advance, a third time window for the first terminal device to send the first message, and determining, according to the third time window, the first time window; and / or, A fourth time window for the second terminal device to send the second message is determined based on the second timing advance, and the second time window is determined based on the fourth time window.

16. The device according to any one of claims 9 to 15, It is characterized in that The network device is a network device in a non-terrestrial network.

17. A communication device, It is characterized in that It includes a processor and an interface circuit, wherein the interface circuit is used to receive signals from other communication devices outside the communication device and transmit them to the processor or send signals from the processor to other communication devices outside the communication device, and the processor is used to implement the method according to any one of claims 1 to 8 through a logic circuit or executing code instructions.

18. A computer program product comprising instructions, It is characterized in that When the instructions are executed by a computing device cluster, the computing device cluster executes the method according to any one of claims 1 to 8.

19. A computer-readable storage medium, It is characterized in that The storage medium stores a computer program or instruction, and when the computer program or instruction is executed by the communication device, the method according to any one of claims 1 to 8 is implemented.

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