Communication method and device

Abstract

The present application relates to a communication method and a device. A remote device receives configuration information from a first access network device, and the configuration information is used to configure a measurement frequency on a sidelink and configure cell information or air interface frequency information. The remote device measures a first type of relay device based on the configuration information, and the first type of relay device is a relay device that operates at the measurement frequency and has camped on or can camp on a cell corresponding to the cell information, or the first type of relay device is a relay device that operates at the measurement frequency and has camped on or can camp on a cell at a frequency corresponding to the air interface frequency information. The remote device transmits a measurement result to the first access network device to determine a communication path of the remote device. The first access network device can learn frequency information of a cell in which the relay terminal device is located, so that a more suitable relay terminal device can be selected when the first access network device selects a relay terminal device for the remote device.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to Chinese Patent Application No. 202111562237.5, entitled “COMMUNICATION METHOD AND DEVICE”, filed with the State Intellectual Property Office of the People's Republic of China on December 20, 2021, which is incorporated herein by reference in its entirety. This application claims priority to Chinese Patent Application No. 202210022645.X, entitled “COMMUNICATION METHOD AND DEVICE”, filed with the State Intellectual Property Office of the People's Republic of China on January 10, 2022, which is incorporated herein by reference in its entirety. This application claims priority to Chinese Patent Application No. 202210108407.0, entitled “COMMUNICATION METHOD AND DEVICE”, filed with the State Intellectual Property Office of the People's Republic of China on January 28, 2022, which is incorporated herein by reference in its entirety.

[0002] The present application relates to the field of communication technologies, and in particular to communication methods and devices. [Background technology]

[0003] When a user equipment (UE) is far away from a network device, for example, when the UE is not in the coverage area of ​​the network device, or when the UE is at the coverage edge of the network device, or when the quality of the link between the UE and the network device is poor, the UE can use another UE to communicate with the network device. Specifically, the other UE can provide a relay service to the UE, so that the UE can communicate with the network device. A UE that communicates with a network device using another UE may be referred to as a remote UE, and a UE that provides a relay service to a remote UE may be referred to as a relay UE.

[0004] When a remote UE is connected to the network using a relay UE, the remote UE can determine whether the remote UE can continue to function as a remote UE. Therefore, the remote UE can measure the cell on which the relay UE operates or camps and perform the determination based on the measurement result. In order to measure the cell on which the relay UE operates or camps, the cell on which the relay UE operates or camps needs to be determined first. Specifically, the remote UE can perform a blind search on each frequency and search for the corresponding cell based on the known physical cell identity (PCI) of the cell on which the relay UE operates or camps. After determining the cell, the remote UE determines whether the new radio cell identity (NCI) broadcast in the system information block 1 (SIB 1) of the cell is the same as the NCI obtained from the relay UE by reading the system information block 1 (SIB 1) of the cell. If the two NCIs are the same, the remote UE can determine that the cell is the cell in which the relay UE operates or camps. Alternatively, if the two NCIs are different, the remote UE needs to continue searching.

[0005] Currently, it can be found that it takes a long time for a remote UE to search for a cell on which a relay UE operates or camps, and in addition, the remote UE needs to perform a blind search on multiple frequencies, which results in high power consumption. Summary of the Invention

[0006] The embodiments of the present application provide a communication method and device for reducing power consumption of a remote UE. [Means for solving the problem]

[0007] According to a first aspect, a first communication method is provided. The method may be executed by a terminal device, a larger device including the terminal device, or a chip system or another functional module. The chip system or the functional module can implement the function of the terminal device. The chip system or the functional module is, for example, disposed in the terminal device. The method includes the steps of: acquiring frequency information of a first cell, the first cell being a cell in which a first relay device is located; determining the first cell based on the frequency information of the first cell and an identifier of the first cell; and measuring the first cell to determine whether the terminal device can function as a remote device in the first cell.

[0008] In this embodiment of the present application, the terminal device can obtain frequency information of the cell where the first relay device is located, and can further determine the cell based on the frequency information and the cell identifier. In this way, there is no need to perform blind searching on multiple frequencies. This reduces the process of blindly searching frequencies and reduces the time required to search cells. In addition, since the process of blindly searching frequencies is reduced, the power consumption of the terminal device is also reduced.

[0009] In relation to the first aspect, in a first optional implementation form of the first aspect, the identifier of the first cell includes the PCI of the first cell and / or the NCI of the first cell. There may be multiple types of identifiers of the first cell. This is not limited in this embodiment of the application.

[0010] In relation to the first aspect or the first optional implementation form of the first aspect, in a second optional implementation form of the first aspect, the step of acquiring the frequency information of the first cell includes a step of receiving a first message including or indicating the frequency information of the first cell from the first relay device. The first relay device transmits the first message, so that the terminal device can receive the first message. The terminal device does not need to transmit a message to the first relay device, so that signaling overhead can be reduced. For example, the first relay device can transmit the first message in a broadcast manner, a unicast manner, etc.

[0011] In relation to the first aspect or the first optional implementation form of the first aspect, in a third optional implementation form of the first aspect, the step of acquiring frequency information of the first cell includes the steps of: transmitting a second message to the first relay device, the second message being used to inquire about frequency information of a cell in which the first relay device is located, or used to inquire about whether the first relay device has camped on a cell at the first frequency, the first cell being a cell at the first frequency; and receiving a first message from the first relay device, the first message including or indicating frequency information of the first cell, or the first message indicating that the first relay device has camped on a cell at the first frequency. The terminal device can transmit the second message. For example, an intermediate device (e.g., a first intermediate device) that satisfies the condition queried in the second message can respond with a message, so that the intermediate device can be selected, thereby reducing the process of the terminal device measuring intermediate devices that do not satisfy the condition, etc., and reducing the power consumption of the terminal device.

[0012] In relation to the second optional implementation of the first aspect or the third optional implementation of the first aspect, in a fourth optional implementation of the first aspect, the first message is the following, namely, a discovery message, or a PC5 RRC message, or an RRC message from a serving access network device of the first relay device. For example, the first message is a discovery message. In this case, the terminal device can receive the first message before establishing a connection with the first relay device, so that the efficiency of the terminal device acquiring the frequency of the first cell can be improved. Alternatively, the first message is a PC5 RRC message. In this case, the terminal device can receive the first message after establishing a connection with the first relay device, so that the first message can be transmitted more appropriately. Alternatively, the first message is from a serving access network device of the first relay device. This is equivalent to the following: The frequency information of the first cell may alternatively be notified to the terminal device by the network. Thus, the terminal device acquires the frequency information of the first cell in a flexible manner.

[0013] In relation to any one of the second optional implementation form of the first aspect to the fourth optional implementation form of the first aspect, in a fifth optional implementation form of the first aspect, the first message further includes an identifier of the first cell. For example, the identifier of the first cell is carried in the first message and transmitted together with the first message. In this way, the terminal device can obtain the frequency information of the first cell and the identifier of the first cell based on one message. This helps to reduce signaling overhead. Alternatively, the identifier of the first cell may not be included in the first message and is transmitted to the terminal device via another message. The message is, for example, from the first relay device or from a serving access network device of the first relay device. This is not specifically limited.

[0014] In relation to any one of the second optional implementation form of the first aspect to the fifth optional implementation form of the first aspect, in a sixth optional implementation form of the first aspect, the first message further includes first information, and the first information indicates that the first cell is not in an access-barred state. Based on the first information, the terminal device can determine whether access to the first cell is permitted as soon as possible, thereby reducing the possibility of accessing an inappropriate cell as much as possible.

[0015] In relation to any one of the second optional implementation form of the first aspect to the sixth optional implementation form of the first aspect, in a seventh optional implementation form of the first aspect, the first message further includes second information, and the second information indicates whether or not the first cell is permitted to search for accessible cells at the frequency of the first cell when the first cell is in an access barred state. For example, all other cells at the frequency of the first cell may have a heavy load, or all other cells at the frequency of the first cell may be in an access barred state. In this case, the second information may indicate that the first cell is not permitted to search for accessible cells at the frequency of the first cell. In this way, invalid search processes of the terminal device can be reduced, and the power consumption of the terminal device can be reduced.

[0016] In relation to the first aspect or any one of the first optional implementation form of the first aspect to the seventh optional implementation form of the first aspect, in an eighth optional implementation form of the first aspect, the method further includes receiving the PCI of the first cell from the first relay device after establishing a connection with the first relay device, or sending a first request message to the access network device and receiving the PCI of the first cell from the access network device, the first request message being used to request to establish a connection with the access network device. The terminal device can obtain the PCI of the first cell in multiple ways, for example, can receive the PCI of the first cell from the first relay device, or can receive the PCI of the first cell from the access network device. The access network device may be, for example, an access network device on which the terminal device camps or operates, or an access network device on which the first relay device camps or operates (e.g., a serving access network device of the first relay device).

[0017] According to a second aspect, a second communication method is provided. The method may be executed by a terminal device, a larger device including the terminal device, or a chip system or another functional module. The chip system or the functional module can implement the function of the terminal device. The chip system or the functional module is, for example, disposed in the terminal device. For example, the terminal device is a relay device, and the relay device is, for example, a first relay device. The method includes a step of transmitting frequency information of a first cell to the terminal device, the frequency information of the first cell being used to determine whether the terminal device can function as a remote device in the first cell, and the first cell being a cell in which the first relay device is located.

[0018] In relation to the second aspect, in a first optional implementation form of the second aspect, the step of transmitting frequency information of the first cell to the terminal device includes a step of transmitting a first message including the frequency information of the first cell to the terminal device.

[0019] In relation to the second aspect or a second optional implementation form of the second aspect, the step of transmitting the frequency information of the first cell to the terminal device includes the steps of receiving a second message from the terminal device, where the second message is used to inquire about frequency information of a cell in which the first relay device is located, or where the second message is used to inquire about whether the first relay device has camped on a cell at the first frequency, and the first cell is a cell at the first frequency, and transmitting a first message to the terminal device, where the first message includes the frequency information of the first cell, or where the first message indicates that the first relay device has camped on a cell at the first frequency.

[0020] In relation to the first optional implementation form of the second aspect or the second optional implementation form of the second aspect, in a third optional implementation form of the second aspect, the first message is one of the following: a discovery message, or a PC5 RRC message, or an RRC message from a serving access network device of the first relay device.

[0021] In relation to any one of the first optional implementation form of the second aspect to the third optional implementation form of the second aspect, in a fourth optional implementation form of the second aspect, the first message further includes an identifier of the first cell, and the identifier of the first cell includes a PCI of the first cell or an NCI of the first cell.

[0022] In relation to any one of the first optional implementation form of the second aspect to the fourth optional implementation form of the second aspect, in a fifth optional implementation form of the second aspect, the first message further includes first information, and the first information indicates that the first cell is not in an access-barred state.

[0023] In relation to any one of the first optional implementation form of the second aspect to the fifth optional implementation form of the second aspect, in a sixth optional implementation form of the second aspect, the first message further includes second information, and the second information indicates whether or not searching for accessible cells on a frequency of the first cell is permitted when the first cell is in an access barred state.

[0024] In relation to the second aspect or any one of the first optional implementation form of the second aspect to the sixth optional implementation form of the second aspect, in a seventh optional implementation form of the second aspect, the method further includes a step of transmitting a PCI of the first cell to the terminal device after establishing a connection with the terminal device.

[0025] For technical effects provided by the second aspect or optional implementations, please refer to the description of the technical effects provided by the first aspect or the corresponding implementations.

[0026] According to a third aspect, a third communication method is provided. The method may be executed by a terminal device, a larger device including a terminal device, or a chip system or another functional module. The chip system or functional module can implement the functions of the terminal device. The chip system or functional module is, for example, disposed in the terminal device. The terminal device is, for example, a remote device. The method includes: receiving configuration information from a first access network device, the configuration information being used to configure a measurement frequency on a sidelink and to configure cell information or air interface frequency information; measuring a first type of relay device based on the configuration information, the first type of relay device being a relay device that operates at the measurement frequency and has camped on or can camp on a cell corresponding to the cell information, or the first type of relay device being a relay device that operates at the measurement frequency and has camped on or can camp on a cell at a frequency corresponding to the air interface frequency information; and transmitting a measurement result to the first access network device, the measurement result being used to determine a communication path of the remote device.

[0027] In this embodiment of the present application, the first access network device can learn frequency information of the cell in which the relay terminal device is located, so that the first access network device can select a more suitable relay terminal device when selecting a relay terminal device for the remote device. For example, the first access network device can select a relay terminal device that operates at a high frequency on the air interface for the remote device, so that the data rate of the remote device can be improved. In addition, the remote device may perform communication via a single connectivity communication path or may perform communication via a multi-connectivity communication path. This helps to improve the communication flexibility of the remote device and also improve the throughput rate of the remote device.

[0028] In relation to the third aspect, in a first optional implementation form of the third aspect, the method further includes a step of receiving a fourth message from the first relay device, the fourth message including information about the first frequency, the first frequency being the frequency of the cell in which the first relay device is located or the frequency of the cell on which the first relay device can camp. In this way, the remote device can obtain information about the first frequency based on the message received from the relay terminal device without sending a message to the relay terminal device, so that the signaling overhead can be reduced.

[0029] In relation to the first optional implementation of the third aspect, in the second optional implementation of the third aspect, the fourth message is a discovery message or a PC5 RRC message. For example, the fourth message may be a discovery message or a PC5 RRC message, or may be another type of message. This is not limited in this embodiment of the application.

[0030] In relation to the first optional implementation of the third aspect or the second optional implementation of the third aspect, in the third optional implementation of the third aspect, the step of measuring the first type relay device based on the configuration information includes the step of measuring or measuring and reporting the first relay device if the first frequency belongs to a frequency corresponding to the air interface frequency information configured based on the configuration information, or if the cell corresponding to the cell information configured based on the configuration information belongs to the first frequency. If the air interface frequency information is configured based on the configuration information and the first frequency belongs to a frequency corresponding to the air interface frequency information configured based on the configuration information, it indicates that the first relay device is an object that needs to be measured. Alternatively, if the cell information is configured based on the configuration information and the cell corresponding to the cell information configured based on the configuration information belongs to the first frequency (or the cell operates at the first frequency), it also indicates that the first relay device is an object that needs to be measured. This is equivalent to the following: the remote device can measure the object configured based on the configuration information to reduce an invalid measurement process of the remote device.

[0031] In relation to the third aspect, in a fourth optional implementation of the third aspect, the method further includes the steps of: transmitting a fifth message to the first relay device, the fifth message being used to inquire about frequency information of a cell in which the first relay device is located, or to inquire about frequency information of a cell in which the first relay device can camp, or to inquire about whether the first relay device has camped on or can camp on a cell at a second frequency, the second frequency being a frequency corresponding to the air interface frequency information configured based on the configuration information; and receiving a sixth message from the first relay device, the sixth message including information about the second frequency, or the sixth message indicating that the first relay device has camped on or can camp on a cell at the second frequency. In this way, the remote device can initially transmit a message to the first relay device. For example, the message transmitted by the remote device is referred to as a fifth message. After receiving the fifth message, the first relay device can send a message, for example, called the sixth message, to the remote device. The remote device may perform measurement based on the sixth message. Since the corresponding information is queried in the fifth message, it may be more useful for the remote device to find suitable relay terminal devices and measure these relay terminal devices.

[0032] In relation to the third aspect or any one of the first optional implementation form of the third aspect to the fourth optional implementation form of the third aspect, in a fifth optional implementation form of the third aspect, the method further includes receiving an RRC reconfiguration message from a first access network device, the RRC reconfiguration message instructing the remote device to handover to a second cell, or instructing the remote device to handover to a first relay device, or instructing the remote device to add the second cell as a secondary cell, or instructing the remote device to add a path for communicating with the network using the first relay device, the first relay device being one of a first type of relay device. The new communication path may be instructed to the remote device based on the RRC reconfiguration message.

[0033] In relation to the fifth optional implementation of the third aspect, in a sixth optional implementation of the third aspect, the RRC reconfiguration message further includes the PCI of the cell in which the first relay device is located. For example, the second access network device can transmit the stored PCI of the cell in which the first relay device is located to the first access network device, and the first access network device can further forward the PCI to the remote device. This provides an implementation in which the remote device obtains the PCI of the cell in which the first relay device is located.

[0034] In relation to the fifth optional implementation of the third aspect or the sixth optional implementation of the third aspect, in a seventh optional implementation of the third aspect, the RRC reconfiguration message further includes frequency information of the cell in which the first relay device is located. For example, the second access network device can transmit the frequency information of the cell in which the first relay device is located to the first access network device, and the first access network device can further forward the frequency information to the remote device. This provides an implementation in which the remote device obtains the frequency information of the cell in which the first relay device is located.

[0035] In relation to the fifth optional implementation of the third aspect, in an eighth optional implementation of the third aspect, the method further includes receiving, from the first relay device, a PCI of a cell in which the first relay device is located after establishing a connection with the first relay device. There may be two ways to provide an implementation in which the remote device obtains the PCI of the cell in which the first relay device is located. In one way, the remote device obtains the PCI of the cell using an access network device (e.g., the first access network device). In another way, the remote device obtains the PCI of the cell using the first relay device. The two methods may be applied separately or in combination.

[0036] In relation to any one of the fifth optional implementation form to the eighth optional implementation form of the third aspect, in a ninth optional implementation form of the third aspect, the method further includes the step of sending first instruction information to the first relay device after establishing a connection to the first relay device, the first instruction information instructing the first relay device to reselect a cell corresponding to the cell information configured based on the configuration information, or instructing the first relay device to reselect a cell at a frequency corresponding to the air interface frequency information configured based on the configuration information. If the first relay device can only camp on the cell corresponding to the configuration information, but is not currently camped on the cell corresponding to the configuration information, the remote device can send the first instruction information to the first relay device to instruct the first relay device to reselect a cell corresponding to the configuration information, so that the first relay device can successfully provide a relay service to the remote device.

[0037] In relation to the third aspect or any one of the first optional implementation form of the third aspect to the ninth optional implementation form of the third aspect, in a tenth optional implementation form of the third aspect, the step of receiving the configuration information from the first access network device includes a step of receiving the configuration information from the first access network device using a second relay device. For example, the remote device may be first connected to the first access network device using the second relay device. In this case, the configuration information transmitted by the first access network device may be transmitted to the remote device using the second relay device.

[0038] According to a fourth aspect, a fourth communication method is provided. The method may be executed by a terminal device, a larger device including the terminal device, or a chip system or another functional module. The chip system or the functional module may implement the function of the terminal device. The chip system or the functional module is, for example, disposed in the terminal device. The terminal device is, for example, a first relay device. The method includes a step of transmitting information about a third frequency to a remote device, the third frequency being a frequency of a cell in which the first relay device is located or a frequency of a cell on which the first relay device can camp, and the information about the third frequency is used to determine a communication path of the remote device.

[0039] For technical effects provided by the fourth aspect, please refer to the description of the technical effects of the third aspect or the corresponding implementation.

[0040] According to a fifth aspect, a fifth communication method is provided. The method may be performed by a first access network device, a larger device including the first access network device, or a chip system or another functional module. The chip system or functional module may implement the function of the first access network device. The chip system or functional module is, for example, disposed in the first access network device. The first access network device is, for example, a base station. The method includes the steps of: transmitting configuration information to a remote device, the configuration information being used to configure a measurement frequency on a sidelink, and configuring cell information or air interface frequency information of a cell on which a relay device operating on the measurement frequency needs to camp on or operate; receiving a measurement result of the relay device from the remote device; and determining a communication path of the remote device based on the measurement result.

[0041] For technical effects provided by the fifth aspect, please refer to the description of the technical effects of the third aspect or the corresponding implementation.

[0042] According to a sixth aspect, a sixth communication method is provided. The method may be performed by a first access network device, a larger device including the first access network device, or a chip system or another functional module. The chip system or the functional module may implement the function of the first access network device. The chip system or the functional module is, for example, located in the first access network device. The first access network device is, for example, a base station. The method includes the steps of sending a handover request message to a second access network device, where the handover request message is used to inquire whether the remote device is willing to access the network using a first relay device served by the second access network device, or the handover request message is used to inquire whether the remote device is willing to access a second cell served by the second access network device, and receiving a handover request response from the second access network device, where the handover request response indicates whether the remote device is willing to access the network using the first relay device, or indicates whether the remote device is willing to access the second cell, and the handover request response further includes frequency information of a cell on which the first relay device is camped or can be camped.

[0043] For technical effects provided by the sixth aspect, please refer to the description of the technical effects of the third aspect or the corresponding implementation.

[0044] According to a seventh aspect, a seventh communication method is provided. The method may be performed by a second access network device, may be performed by a larger device including the second access network device, or may be performed by a chip system or another functional module. The chip system or the functional module may implement the functions of the second access network device. The chip system or the functional module may be, for example, located in the second access network device. The second access network device may be, for example, a base station. The method includes the steps of receiving a handover request message from a first access network device, where the handover request message is used to inquire whether the remote device is willing to access the network using a first relay device served by a second access network device, or the handover request message is used to inquire whether the remote device is willing to access a second cell served by the second access network device, and sending a handover request response to the first access network device, where the handover request response indicates whether the remote device is willing to access the network using the first relay device, or indicates whether the remote device is willing to access the second cell, and the handover request response further includes frequency information of a cell on which the first relay device is camped or can be camped.

[0045] For technical effects provided by the seventh aspect, please refer to the description of the technical effects of the third aspect or the corresponding implementation.

[0046] According to an eighth aspect, an eighth communication method is provided. The method may be executed by a terminal device, may be executed by a larger device including a terminal device, or may be executed by a chip system or another functional module. The chip system or the functional module may implement the function of the terminal device. The chip system or the functional module may be disposed in, for example, the terminal device. The terminal device may be, for example, a remote device. The method includes the steps of receiving configuration information from an access network device, the configuration information being used to configure a first type of measurement object and a second type of measurement object, and a communication path of the remote device corresponding to the first type of measurement object being different from a communication path of the remote device corresponding to the first type of measurement object; measuring the first type of measurement object based on the configuration information; and measuring the second type of measurement object if the measurement result of the first type of measurement object does not satisfy the first condition.

[0047] In this embodiment of the present application, the access network device can configure two types of measurement objects, but the remote device determines the specific type of measurement object to be measured based on the first condition. In this case, the remote device does not need to measure both of the two types of measurement objects, thereby reducing power consumption. In addition, the access network device does not need to configure the measurement objects separately, and the remote device can determine the specific type of measurement object to be measured, thereby reducing measurement delay.

[0048] According to a ninth aspect, a ninth communication method is provided. The method may be executed by a terminal device, a larger device including a terminal device, or a chip system or another functional module. The chip system or the functional module may implement the function of the terminal device. The chip system or the functional module is, for example, disposed in the terminal device. The terminal device is, for example, a remote device. The method includes the steps of receiving configuration information from an access network device, the configuration information being used to configure a measurement event, the measurement event including a value of a measurement result of a first type of measurement object being less than a first threshold and a value of a measurement result of a second type of measurement object being equal to or greater than a second threshold, and a communication path of the remote device corresponding to the first type of measurement object being different from a communication path of the remote device corresponding to the first type of measurement object; measuring the first type of measurement object and the second type of measurement object; and transmitting the measurement result of the first type of measurement object and / or the measurement result of the second type of measurement object to the access network device based on the measurement event.

[0049] In this embodiment of the present application, the access network device can select a preferred reported measurement result based on a configured measurement event, and the remote device can transmit the measurement result to the access network device based on the measurement event, so that the transmitted measurement result better meets the requirements of the access network device, thereby reducing redundant reporting of the remote device and reducing transmission overhead.

[0050] According to a tenth aspect, a tenth communication method is provided. The method may be performed by a terminal device, a larger device including the terminal device, or a chip system or another functional module. The chip system or the functional module may implement the function of the terminal device. The chip system or the functional module is, for example, located in the terminal device. The terminal device is, for example, a remote device. The method includes the steps of receiving configuration information from the access network device, where the configuration information is used to configure a first measurement event, a second measurement event, and a third measurement event, where the first measurement event includes a value of a measurement result of a first type of measurement object being less than a first threshold, the second measurement event includes a value of a measurement result of a second type of measurement object being equal to or greater than a second threshold, and the third measurement event includes a value of a measurement result of the first type of measurement object being equal to or greater than the first threshold, where a communication path of the remote device corresponding to the first type of measurement object is different from a communication path of the remote device corresponding to the first type of measurement object; measuring the first type of measurement object and the second type of measurement object; and transmitting the measurement results of the first type of measurement object and / or the measurement results of the second type of measurement object to the access network device based on the first measurement event, the second measurement event, and the third measurement event.

[0051] In this embodiment of the present application, the access network device can select a preferred reported measurement result based on a configured measurement event, and the remote device can transmit the measurement result to the access network device based on the measurement event, so that the transmitted measurement result better meets the requirements of the access network device, thereby reducing redundant reporting of the remote device and reducing transmission overhead.

[0052] According to an eleventh aspect, a communication device is provided. The communication device may be a terminal device, a remote device, or a first relay device according to any one of the first to tenth aspects. The communication device has a function of the aforementioned terminal device, the aforementioned remote device, or the aforementioned first relay device. The communication device is, for example, a terminal device, a remote device, or a first relay device, or is a functional module in the remote device or the first relay device, for example, a baseband device or a chip system. In an optional implementation, the communication device includes a baseband device and a radio frequency device. In another optional implementation, the communication device includes a processing unit (sometimes referred to as a processing module) and a transceiver unit (sometimes referred to as a transceiver module). The transceiver unit can implement a transmitting function and a receiving function. When the transceiver unit implements a transmitting function, the transceiver unit may be referred to as a transmitting unit (sometimes referred to as a transmitting module). When the transceiver unit implements a receiving function, the transceiver unit may be referred to as a receiving unit (sometimes referred to as a receiving module). The transmitting unit and the receiving unit may be the same functional module, and the functional module is called a transceiver unit, and the functional module can implement the transmitting function and the receiving function. Alternatively, the transmitting unit and the receiving unit may be different functional modules, and the transceiver unit is a collective term for these functional modules.

[0053] In an optional implementation, the communication device further includes a storage unit, the processing unit is coupled to the storage unit and configured to execute a program or instructions in the storage unit to enable the communication device to perform functions of the terminal device, the remote device, or the first relay device according to any one of the first to tenth aspects.

[0054] According to a twelfth aspect, a communication device is provided. The communication device may be the first access network device or the second access network device according to any one of the first to tenth aspects. The communication device has the function of the first access network device or the second access network device. The communication device is, for example, the first access network device or the second access network device, or is a functional module in the first access network device or the second access network device, for example, a baseband device or a chip system. In an optional implementation, the communication device includes a baseband device and a radio frequency device. In another optional implementation, the communication device includes a processing unit (sometimes referred to as a processing module) and a transceiver unit (sometimes referred to as a transceiver module). For the implementation of the transceiver unit, please refer to the description of the eleventh aspect.

[0055] In an optional implementation, the communication device further includes a storage unit. The processing unit is coupled to the storage unit and configured to execute programs or instructions in the storage unit to enable the communication device to perform functions of the first access network device or the second access network device according to any one of the first to tenth aspects.

[0056] According to a thirteenth aspect, a computer-readable storage medium is provided. The computer-readable storage medium is configured to store a computer program or instructions. When the computer program or instructions are executed, a method executed by the terminal device, the remote device, the first relay device, the first access network device, or the second access network device in the above-mentioned aspect is implemented.

[0057] According to a fourteenth aspect there is provided a computer program product comprising instructions, when run on a computer, for implementing a method according to the previous aspect.

[0058] According to a fifteenth aspect, there is provided an apparatus comprising one or more units configured to perform a method according to any embodiment of the present application.

[0059] According to a sixteenth aspect, there is provided a communication system including a communication apparatus configured to implement functionality of a first access network device according to the twelfth aspect, and including a communication apparatus configured to implement functionality of a second access network device according to the twelfth aspect.

[0060] Optionally, the communication system further comprises a communication apparatus configured to implement functionality of the remote device according to the eleventh aspect.

[0061] Optionally, the communication system further includes a communication apparatus configured to implement functionality of the first relay device according to the eleventh aspect.

[0062] According to a 17th aspect, there is provided a communication system including a communication apparatus configured to implement functions of a terminal device or a remote device according to the 11th aspect, and including a communication apparatus configured to implement functions of a first relay device according to the 12th aspect. [Brief description of the drawings]

[0063] [Figure 1] FIG. 1 is a schematic diagram of an application scenario according to an embodiment of the present application. [Diagram 2] 1 is a flowchart of seven communication methods according to an embodiment of the present application. [Figure 3A] 1 is a flowchart of seven communication methods according to an embodiment of the present application. [Figure 3B] 1 is a flowchart of seven communication methods according to an embodiment of the present application. [Figure 4A] 1 is a flowchart of seven communication methods according to an embodiment of the present application. [Figure 4B] 1 is a flowchart of seven communication methods according to an embodiment of the present application. [Diagram 5] 1 is a flowchart of seven communication methods according to an embodiment of the present application. [Figure 6] 1 is a flowchart of seven communication methods according to an embodiment of the present application. [Figure 7] 1 is a schematic diagram of an apparatus according to an embodiment of the present application; [Figure 8] FIG. 2 is a schematic diagram of another apparatus according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0064] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the following further describes the embodiments of the present application in detail with reference to the accompanying drawings.

[0065] In order to facilitate understanding by those skilled in the art, some terms or concepts in the embodiments of the present application are explained below.

[0066] In the embodiment of the present application, the terminal device is a device having a wireless transceiver function, and may be a fixed device, a mobile device, a handheld device (e.g., a mobile phone), a wearable device, an in-vehicle device, or a wireless device (e.g., a communication module, a modem, or a chip system) embedded in the aforementioned devices. The terminal device may be configured to connect people, objects, machines, etc., and may be widely used in various scenarios. For example, the terminal device includes, but is not limited to, terminal devices in scenarios such as cellular communication, device-to-device (D2D) communication, 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 scenarios, smart grid, smart furniture, smart office, smart wearable, smart transportation, smart city, unmanned aerial vehicle, robot, etc. The terminal device may also be referred to as user equipment (UE), terminal, access station, UE station, remote station, wireless communication device, user equipment, etc. For ease of explanation, an example in which the terminal device is a UE is used in the description in the embodiment of the present application.

[0067] In an embodiment of the present application, the network device may include, for example, an access network device and / or a core network device. The access network device is a device having a radio transceiver function and configured to communicate with a terminal device. The access network device includes, but is not limited to, a base station (base transceiver station (BTS), NodeB, eNodeB / eNB, or gNodeB / gNB), a transmission reception point (TRP), a base station evolved after the 3rd generation partnership project (3GPP), an access node in a wireless fidelity (Wi-Fi) system, a relay node, a backhaul node, etc. The base station may be a macro base station, a micro base station, a picocell base station, a small cell, a relay station, etc. The multiple base stations may support networks of the same access technology or networks of different access technologies. The base station may include one or more co-site or non-co-site transmission reception points. Alternatively, the access network device may be a radio controller, a centralized unit (CU), and / or a distributed unit (DU) in a cloud radio access network (CRAN) scenario. Alternatively, the access network device may be a server, etc. For example, the access network device in a vehicle to everything (V2X) technology may be a road side unit (RSU). In the following, an explanation is provided using an example in which the access network device is a base station. The base station can communicate with a terminal device, or can also communicate with the terminal device through a relay station. The terminal device may communicate with multiple base stations using different access technologies.The core network device is configured to implement functions such as mobility management, data processing, session management, policy and charging. The names of devices implementing core network functions in different access technology systems may be different. This is not limited in the embodiments of this application. The 5G system is used as an example. The core network device includes an access and mobility management function (AMF), a session management function (SMF), a policy control function (PCF), a user plane function (UPF), etc.

[0068] In the embodiment of the present application, the communication device configured to implement the functions of the network device may be a network device, or may be a device, such as a chip system, that can support the network device in implementing the functions. The device may be installed in the network device. In the technical solution provided in the embodiment of the present application, an example in which the device configured to implement the functions of the network device is a network device is used to explain the technical solution provided in the embodiment of the present application.

[0069] In the embodiments of the present application, unless otherwise specified, the number of nouns refers to "singular or plural nouns", i.e., "one or more". "At least one" means one or more, and "multiple" means two or more. The term "and / or" describes an association relationship between associated objects and indicates that three relationships may exist. For example, A and / or B can indicate the following three cases: when only A is present, when both A and B are present, and when only B is present. Each of A and B may be singular or plural. The symbol " / " generally indicates an "or" relationship between associated objects. For example, A / B indicates A or B. "At least one of the following items (parts)" or similar expressions refers to any combination of these items, including any combination of singular items (parts) or multiple items (parts). For example, at least one of items a, b, or c refers to a, b, c, a and b, a and c, b and c, or a, b, and c, where a, b, and c may be singular or plural.

[0070] Ordinals such as "first" and "second" referred to in the embodiments of the present application are used to distinguish between multiple objects, and are not intended to limit the size, content, order, time sequence, priority, importance, etc. of the multiple objects. For example, the first cell and the second cell may be the same cell or different cells. In addition, such names do not indicate the different locations, coverage ranges, corresponding access network devices, priority, importance, etc. of the two cells. In addition, the step numbers in the embodiments described in the present application are only used to distinguish between different steps, and are not used to limit the order of the steps. For example, S201 may occur before S202, may occur after S202, or may occur simultaneously with S202.

[0071] When camping on a cell, a UE may determine whether the UE can function as a remote UE in the cell. The UE may determine whether the UE can function as a remote UE in the cell based on the signal strength of the cell. For example, the UE may determine whether a discovery message can be received and / or transmitted in a sidelink (SL) according to a certain threshold rule to help further determine whether an access stratum (AS) threshold is met. For example, based on a base station configuration (e.g., system information configuration), when the signal quality of the UE in the cell where the UE camps is lower than a value obtained by subtracting an offset from a threshold (e.g., a remote UE highest threshold (threshHighRemote)), the UE is considered to be able to function as a remote UE in the cell. Alternatively, if the signal quality of the UE in the cell where the UE camps is higher than a threshold (e.g., threshHighRemote), the UE is considered not to meet the condition for serving as a remote UE in the cell. The offset is, for example, hystMaxRemote (hystMaxRemote).

[0072] If the remote UE can function as a remote UE in the cell where the remote UE is currently camped, the remote UE can search for and access the relay UE, so that the remote UE can camp on the cell where the relay UE is located. The cell where the relay UE is located is, for example, the camping cell or serving cell of the relay UE. In the case of a remote UE camping on the cell where the relay UE is located using the relay UE, the NCI of the cell where the relay UE is located can be obtained using a discovery message from the relay UE. The NCI is a unique cell ID in a public land mobile network (PLMN). The most significant bit of the NCI indicates a unique gNB ID in the PLMN. The least significant bit indicates a cell ID under the gNB ID. Now, the remote UE can further obtain the PCI of the cell where the relay UE is located. The PCI is a unique cell ID on the Uu frequency on which the relay UE is camped or operating.

[0073] After the remote UE discovers the relay UE and establishes a connection to the relay UE, the remote UE can determine whether the remote UE can continue to function as a remote UE. Therefore, the remote UE can measure the cell in which the relay UE operates or camps and perform a determination based on the measurement result. In order to measure the cell in which the relay UE operates or camps, the cell in which the relay UE operates or camps needs to be determined first. Specifically, the remote UE can perform a blind search on each frequency and search for the corresponding cell based on the known PCI of the cell in which the relay UE operates or camps. After determining the cell, the remote UE determines whether the NCI broadcasted in SIB 1 is the same as the NCI obtained from the relay UE by reading the SIB 1 of the cell. If the two NCIs are the same, the remote UE can determine that the cell is the cell in which the relay UE operates or camps. Alternatively, if the two NCIs are different, the remote UE should continue searching.

[0074] Currently, it can be found that it takes a long time for a remote UE to search for a cell on which a relay UE operates or camps, and in addition, the remote UE needs to perform a blind search on multiple frequencies, which results in high power consumption.

[0075] In view of this, a technical solution is provided in an embodiment of the present application. In the embodiment of the present application, the terminal device can obtain frequency information of the cell in which the first relay device is located, and can further determine the cell based on the frequency information and the PCI of the cell. In this way, there is no need to perform blind searching on multiple frequencies. This reduces the process of blindly searching frequencies and reduces the time required to search for a cell. In addition, since the process of blindly searching frequencies is reduced, the power consumption of the terminal device is also reduced.

[0076] The technical solutions provided in the embodiments of the present application may be applied to the 4th generation (4G) mobile communication technology system, for example, a long term evolution (LTE) system, or may be applied to a 5G system, for example, a new radio (NR) system, or may further be applied to a next generation mobile communication system or another similar communication system, which is not specifically limited.

[0077] This application relates to a UE to network relay mechanism. This mechanism may be used to improve the coverage of a cellular network. The topology structure of this mechanism is shown in Figure 1. Alternatively, Figure 1 may be regarded as a communication network architecture to which an embodiment of this application is applied. A relay UE is located within the coverage area of ​​a radio access network (RAN) node (which can be understood as a cellular network base station) of a cellular network, i.e., the relay UE can directly communicate with the RAN via a Uu interface. A remote UE can communicate with the relay UE via a PC5 interface and transmit data of the remote UE to the relay UE. The relay UE then forwards data of the remote UE to the RAN and core network via the Uu interface and interacts with a data network (DN) via the core network. Alternatively, data to be transmitted to the remote UE from the DN arrives at the core network, the core network transmits data to the RAN, the RAN transmits data to the relay UE via the Uu interface, and then the relay UE forwards data to the remote UE via the PC5 interface. In Figure 1, a 5G core (5GC) network is used as an example of a core network.

[0078] In order to better describe the embodiments of the present application, the following describes the methods provided in the embodiments of the present application with reference to the accompanying drawings. In the accompanying drawings corresponding to the embodiments of the present application, all optional steps are represented by dashed lines. For ease of description, in the embodiments of the present application, an example is used in which the terminal device is a UE, the remote device is a remote UE, and the relay device is a relay UE (for example, the first relay device is a first relay UE). All the methods provided in the embodiments of the present application may be applied to the network architecture shown in FIG. 1. For example, the remote UE or UE in the embodiments of the present application is the remote UE in FIG. 1, the access network device or the second access network device in the embodiments of the present application is the RAN in FIG. 1, and the relay UE or the first relay UE in the embodiments of the present application is the relay UE in FIG. 1. Furthermore, in the embodiments of the present application, the air interface is, for example, a Uu interface.

[0079] An embodiment of the present application provides a first communication method. Figure 2 is a flowchart of the method.

[0080] S201: The UE determines that the UE can function as a remote UE.

[0081] For example, the UE may measure a second cell to obtain a measurement result. The second cell may be the UE's current serving cell or the cell on which the UE is currently camped. In addition, the UE may further read the system information of the second cell and determine whether the UE can function as a remote UE based on a first threshold and an offset provided in the system information. For example, if the value of the measurement result is less than the difference between the first threshold and the offset, the UE may function as a remote UE, and the UE may start searching for a relay UE. For example, the UE may execute S202. Alternatively, if the value of the measurement result is equal to or greater than the difference between the first threshold and the offset, the UE may not be a remote UE. In this case, the subsequent steps do not need to be executed.

[0082] S201 is an optional step. For example, the UE does not need to perform S201, but can directly perform S202.

[0083] S202: The UE obtains frequency information of a first cell. The first cell is a cell in which a first relay UE is located. The cell in which the first relay UE is located is, for example, a serving cell or a primary cell (PCell) of the first relay UE (e.g., the first relay UE is in a radio resource control (RRC) connected state), or a cell in which the first relay UE camps (e.g., the first relay UE is in an RRC idle state or an RRC inactive state). When the UE searches for a relay UE, information exchange with multiple relay UEs may be involved. In this embodiment of the present application, the interaction between the UE and the first relay UE is used as an example for explanation.

[0084] Optionally, the UE can obtain the frequency information of the first cell in two ways, which are described separately below. Since the UE and the first relay UE are involved below, in order to facilitate the distinction, the UE is temporarily called a remote UE in the following step description. However, in reality, the remote UE is not connected to the network using the first relay UE, and only expects to be connected to the network using the first relay UE.

[0085] 1. Method 1 In the first scheme, the relay UE transmits a message. For example, the message transmitted by the relay UE is referred to as a first message. The first message may include frequency information of the first cell. Alternatively, the first message does not include the frequency information of the first cell, but the first message can indicate the frequency information of the first cell. After receiving the first message, the remote UE can determine the frequency information of the first cell. The frequency information of the first cell is, for example, information such as an absolute radio frequency channel number (ARFCN) or a band of the first cell.

[0086] For example, the first message may be a discovery message, or a PC5 RRC message, or an RRC message from a serving access network device of the first relay UE. This is equivalent to the following: The serving access network device sends the first message to the remote UE using the first relay UE. If the first message is a discovery message, the remote UE can receive the first message from the first relay UE after establishing a connection to the first relay UE, or can receive the first message before establishing a connection to the first relay UE. This helps the remote UE to obtain frequency information of the first cell as soon as possible. Optionally, if the first message is a discovery message, the first relay UE can send the first message in a broadcast or unicast manner.

[0087] If the first message is a PC5 RRC message, the remote UE can receive the first message from the first relay UE after establishing a connection to the first relay UE, and the first relay UE can transmit the first message in a broadcast manner or a unicast manner.

[0088] If the first message is from a serving access network device of the first relay UE, the remote UE may receive the first message from the first relay UE after establishing a connection to the first relay UE, and both the remote UE and the first relay UE may be in an RRC connected state.

[0089] Optionally, the first message may further include an identifier of the first cell. The identifier of the first cell may include, for example, the NCI of the first cell and / or the PCI of the first cell. In other words, the identifier of the first cell and the frequency information of the first cell may be transmitted using one message. Alternatively, the first message does not include the identifier of the first cell. For example, the remote UE obtains the identifier of the first cell using a message other than the first message. For example, the message is a discovery message, a PC5 RRC message, or an RRC message from a serving access network device of the first relay UE. The type of the message and the type of the first message may be the same (e.g., both are discovery messages) or different (e.g., the message is a PC5 RRC message and the first message is a discovery message).

[0090] Optionally, the first message may further include first information. The first information may indicate that the first cell is in an access barred state or is not in an access barred state. For example, the first information is cell bar information. If the first cell is in a cell bar state, it indicates that the first cell is in an access barred state, or if the first cell is not in a cell bar state, it indicates that the first cell is not in an access barred state. If the first cell is in an access barred state, in principle, the remote UE should not access the first cell. If the first cell is not in an access barred state, the remote UE can access the first cell. Based on the first information, the remote UE can determine whether access to the first cell is permitted as soon as possible, thereby reducing the possibility of accessing an inappropriate cell as much as possible.

[0091] Alternatively, the first information may not be included in the first message and may be sent to the remote UE using another message. For example, the message may be a discovery message, a PC5 RRC message, or an RRC message from a serving access network device of the first relay UE. The type of the message and the type of the first message may be the same (e.g., both are discovery messages) or may be different (e.g., the message is a discovery message and the first message is a PC5 RRC message).

[0092] When the first message includes the first information, optionally, the first message may further include second information. The second information may indicate whether the UE is permitted to search for accessible cells on the frequency of the first cell when the first cell is in a barred state, or in other words, the second information may indicate whether the UE is permitted to search for accessible cells on the same frequency as the frequency of the first cell when the first cell is in a barred state. For example, the second information may be intraFreqReselection (IFRI) or other information. For example, if the second information indicates that the UE is permitted to search for accessible cells on the frequency of the first cell when the first cell is in a barred state (e.g., the second information is IFRI, and IFRI indicates permission), and the first information indicates that the first cell is in a barred state, the remote UE may continue to search for another cell on the frequency of the first cell to determine whether the remote UE can access another cell. However, if the second information indicates that searching for accessible cells on the frequency of the first cell is not permitted when the first cell is in an access barred state (e.g., the second information is IFRI, and the IFRI indicates non-authorization), and the first information indicates that the first cell is in an access barred state, the remote UE cannot search for another cell on the frequency of the first cell. In this case, the remote UE may terminate the process of searching for cells, or the remote UE may search for cells on another frequency. For example, all other cells on the frequency of the first cell may have a heavy load, or all other cells on the frequency of the first cell may be in a cell bar state. In this case, the second information may indicate that searching for accessible cells on the frequency of the first cell is not permitted. In this way, the invalid search process of the remote UE may be reduced, and the power consumption of the remote UE may be reduced.

[0093] Alternatively, the second information may not be included in the first message and may be sent to the remote UE using another message. For example, the message may be a discovery message, a PC5 RRC message, or an RRC message from a serving access network device of the first relay UE. The type of the message and the type of the first message may be the same (e.g., both are discovery messages) or may be different (e.g., the message is a discovery message and the first message is a PC5 RRC message). Also, the message including the first information and the message including the second information may be the same message or different messages.

[0094] 2. The second method In the second method, the remote UE may first transmit a message to the relay UE. For example, the message transmitted by the remote UE is referred to as a second message. After receiving the second message, the relay UE may transmit a message, for example, referred to as a first message, to the remote UE. The first message may include frequency information of the first cell. Alternatively, the first message may not include frequency information of the first cell, but the first message may indicate frequency information of the first cell. After receiving the first message, the remote UE may determine frequency information of the first cell. The frequency information of the first cell is, for example, information such as the ARFCN or band of the first cell.

[0095] For example, the second message is a discovery message, a PC5 RRC message, or an RRC message sent to a serving access network device of the first relay UE. The type of the second message and the type of the first message may be the same (e.g., both are discovery messages), or may be different (e.g., the second message is a discovery message and the first message is a PC5 RRC message). If the second message is a discovery message, the remote UE may send the second message after establishing a connection to the first relay UE, and may send the second message before establishing a connection to the first relay UE. This helps the remote UE to obtain frequency information of the first cell as soon as possible. Optionally, if the second message is a discovery message, the remote UE may send the second message in a broadcast or unicast manner.

[0096] If the second message is a PC5 RRC message, the remote UE may send the second message to the first relay UE after establishing a connection to the first relay UE, and the first relay UE may send the first message in a broadcast manner or a unicast manner.

[0097] If the second message is sent to a serving access network device of the first relay UE, the remote UE may send the second message to the first relay UE after establishing a connection to the first relay UE, and both the remote UE and the first relay UE may be in an RRC connected state.

[0098] Optionally, the second message includes an identifier of a cell in which the remote UE operates or camps. The cell is, for example, referred to as a second cell. The identifier of the second cell includes, for example, an NCI and / or a PCI of the second cell.

[0099] In addition, optionally, the second message may include inquiry information. The inquiry information may be used to inquire (or ask or request) an air interface frequency on which the first relay UE operates or camps, or the inquiry information is used to inquire (or ask or request) whether the first relay UE operates or camps on an air interface frequency (or the inquiry information is used to inquire whether the first relay UE operates or camps on an air interface frequency in a cell). For example, the air interface frequency is a first frequency. When the inquiry information is used to inquire about an air interface frequency on which the first relay UE operates or camps, the inquiry information may not include specific air interface frequency information and is only used to inquire about an air interface frequency on which the first relay UE operates or camps. After receiving the inquiry information, the first relay UE can send a first message to the remote UE, and the first message indicates (or includes) information about the frequency on which the first relay UE operates or camps. For example, the first message may include or indicate frequency information of a first cell, where the first cell is a cell in which the first relay UE operates or camps.

[0100] Alternatively, when the inquiry information is used to inquire whether the first relay UE operates or camps on the first frequency, the inquiry information may include information about the first frequency. The first frequency corresponding to the information about the first frequency is, for example, an air interface frequency on which the relay UE operates or camps, where the remote UE is expected to provide service to the remote UE. The information about the first frequency includes, for example, information about an ARFCN or a band. After the first relay UE receives the inquiry information, if the frequency on which the first relay UE operates or camps is the first frequency, for example, the frequency on which the first relay UE operates or camps is a frequency corresponding to an ARFCN, or the frequency on which the first relay UE operates or camps belongs to a band, the first relay UE can send a first message to the remote UE. In this case, the first message can include or indicate frequency information of the cell on which the first relay UE operates or camps. Alternatively, the first message may not include or indicate frequency information of the cell on which the first relay UE operates or camps. For example, the first message may indicate that the first relay UE has camped on the first frequency, or may indicate that the first relay UE has camped on the cell of the first frequency. For example, the first message may use one bit to carry out the indication. In this way, the overhead of the first message may be reduced. Alternatively, the frequency on which the first relay UE operates or camps may not be the first frequency.In this case, the first relay UE may not send a message to the remote UE (e.g., may not send the first message), or the first relay UE may send a message to the remote UE, where the message includes or indicates frequency information of the cell in which the first relay UE operates or camps, or indicates that the first relay UE will not camp on the first frequency.

[0101] Alternatively, the information about the first frequency may not include information about the ARFCN or band, but may include other information. For example, the remote UE expects to search for a relay UE camped on a high frequency on the air interface to improve the data rate of the remote UE. In this case, the information included in the inquiry information about the first frequency may alternatively be a frequency threshold. An air interface frequency higher than the frequency threshold is considered as an air interface frequency that satisfies the condition. After the first relay UE receives the inquiry information, if the frequency on which the first relay UE operates or camps is the first frequency, for example, the frequency on which the first relay UE operates or camps is higher than the frequency threshold, the first relay UE may send a first message to the remote UE. In this case, the first message may include or indicate frequency information of the cell on which the first relay UE operates or camps. Alternatively, the first message may not include or indicate frequency information of the cell on which the first relay UE operates or camps. For example, the first message may indicate that the first relay UE has camped on the first frequency, or may indicate that the first relay UE has camped on a cell of the first frequency. For example, the first message may use one bit to carry out the indication. In this way, the overhead of the first message may be reduced. Alternatively, the frequency on which the first relay UE operates or camps may not be the first frequency. In this case, the first relay UE may not send a message to the remote UE (e.g., may not send the first message), or the first relay UE may send a message to the remote UE, where the message includes or indicates frequency information of the cell in which the first relay UE operates or camps, or indicates that the first relay UE will not camp on the first frequency.

[0102] Optionally, if the first relay UE is a release 17 UE, the second message includes the NCI of the second cell, and the first relay UE determines that the NCI of the second cell is the same as the NCI of the first cell, the first relay UE may determine the content of the first message in the above manner and may determine whether to transmit the first message. However, if the first relay UE determines that the NCI of the second cell is different from the NCI of the second cell, the first relay UE may not transmit a message (e.g., not transmit the first message) to the remote UE. The different NCI may indicate that the access network device corresponding to the first cell is different from the access network device corresponding to the second cell. However, Release 17 requires that only in the case of a co-site, one UE can switch from a direct connection path between the UE and the access network device to an indirect connection path in which the access network device is accessed using the relay UE. Therefore, if the NCI of the second cell is different from the NCI of the second cell, it indicates that the remote UE and the first relay UE are located in different access network devices, and the remote UE cannot use the first relay UE to access. Therefore, in this case, the first relay UE may not need to respond with a message to the remote UE.

[0103] For the implementation of the first message, please refer to the above description for information such as the type of the first message or the contents included in the first message (e.g., which may include one or more of the first cell identifier, the first information, or the second information).

[0104] The remote UE can obtain the frequency information of the first cell in any of the above two ways. Alternatively, in addition to the above manner, the remote UE can obtain the frequency information of the first cell in another way, which is not limited in this embodiment of the application.

[0105] S203: The remote UE establishes a connection to the first relay UE. The remote UE can establish a sidelink connection to the first relay UE.

[0106] The remote UE can perform a similar interaction process with the multiple relay UEs as in S202. In S203, the remote UE can establish a connection to some or all of the multiple relay UEs. In this embodiment of the present application, an example is used in which the remote UE establishes a connection to the first relay UE.

[0107] If the remote UE obtains the first information, and the first information indicates that the first cell is not in an access barred state, S203 and subsequent steps may be executed. Alternatively, if the first information indicates that the first cell is in an access barred state, the remote UE does not need to execute S203 and subsequent steps. For example, the remote UE may re-search for cells and reselect a relay UE. If the remote UE needs to re-search for cells, and the remote UE obtains the second information, and the second information indicates that the remote UE is permitted to search for accessible cells on the frequency of the first cell when the first cell is in an access barred state, the remote UE may continue to search for cells on the frequency of the first cell. However, if the second information indicates that the remote UE is not permitted to search for accessible cells on the frequency of the first cell when the first cell is in an access barred state, the remote UE may not search for cells on the frequency of the first cell. For example, the remote UE may search for cells at frequencies other than the frequency, or the remote UE may stop the search process and terminate the process. When the remote UE searches for cells at frequencies other than the frequency and the remote UE determines a specific relay UE in the search process, the remote UE needs to determine whether the frequency of the cell on which the relay UE operates or camps is the frequency of the first cell. If the frequency of the cell on which the relay UE operates or camps is the frequency of the first cell, the remote UE needs to abandon the relay UE.

[0108] S203 is an optional step, and the remote UE may not establish a connection with the first relay UE. In addition, S203 may occur after S202 or before S202.

[0109] Optionally, the remote UE may further obtain the PCI of the first cell. For example, after establishing a connection with the remote UE, the first relay UE may send the PCI of the first cell to the remote UE. Alternatively, after establishing a connection to the first relay UE, the remote UE may expect to establish a connection to an access network device corresponding to the first cell. In this case, the remote UE may send an RRC establishment request message to the access network device. After receiving the RRC establishment request message, the access network device may send an RRC establishment response message to the remote UE. The RRC establishment response message may include the PCI of the first cell.

[0110] As mentioned above, the first message may include an identifier of the first cell, and the identifier of the first cell may include the PCI of the first cell. This solution does not contradict the solution in which the remote UE acquires the PCI of the first cell in this specification. For example, the remote UE may receive the PCI of the first cell multiple times. Alternatively, the identifier of the first cell and included in the first message may be the NCI of the first cell. In this case, the remote UE in this specification may further acquire the PCI of the first cell.

[0111] S204: The remote UE determines the first cell based on the frequency information of the first cell and the identifier of the first cell. The remote UE determines the first cell based on the frequency information of the first cell and the identifier of the first cell can alternatively be understood as follows: the remote UE discovers the first cell by searching, or the remote UE discovers the first cell.

[0112] For example, the identifier of the first cell is the PCI of the first cell. In this case, the remote UE performs a search on a frequency corresponding to the frequency information of the first cell, for example, discovering one or more cells by the search. The remote UE can uniquely determine a cell from the one or more cells based on the PCI of the first cell. Optionally, after determining the cell, the remote UE may further read system information, such as SIB 1 in the cell, and determine the NCI of the cell based on SIB 1. The remote UE can compare the NCI of the cell with the NCI of the first cell. If the two are consistent, the remote UE can determine that the cell is the first cell.

[0113] Alternatively, the identifier of the first cell is the NCI of the first cell. In this case, the remote UE performs a search on a frequency corresponding to the frequency information of the first cell, for example, discovers one or more cells by searching. The remote UE can read system information, such as SIB 1, of each cell found by the search, determine the NCI of each cell based on SIB 1, and compare the read NCI with the NCI of the first cell. If the NCI of a particular cell matches the NCI of the first cell, the remote UE can determine that the cell is the first cell.

[0114] It may be found that the remote UE can obtain frequency information of the first cell in which the first relay UE is located, and can further determine the first cell based on the frequency information and the identifier of the first cell. In this way, there is no need to perform blind search on multiple frequencies. This reduces the process of blindly searching frequencies and reduces the time required to search cells. In addition, since the process of blindly searching frequencies is reduced, the power consumption of the remote UE is also reduced.

[0115] S205: The remote UE measures the first cell.

[0116] For example, the remote UE receives a downlink reference signal in the first cell, where the downlink reference signal is, for example, a synchronization signal and physical broadcast channel block (SSB) or a channel state information-reference signal (CSI-RS). The remote UE measuring the downlink reference signal may be regarded as measuring the first cell.

[0117] S206: The remote UE determines whether the remote UE can function as a remote UE in the first cell based on the measurement result. Alternatively, the remote UE determines whether the remote UE can access the first cell using a relay UE based on the measurement result. Alternatively, the remote UE determines whether the remote UE can function as a remote UE based on the measurement result.

[0118] For example, the remote UE determines whether a discovery message can be received or transmitted on the sidelink based on whether a threshold condition is met to evaluate the status of the access stratum (AS layer). For example, if the measurement result value of the first cell (serving cell, primary cell, or camping cell) is less than a value (e.g., threshHighRemote) obtained by subtracting an offset from the threshold A, the remote UE is determined to meet the threshold condition, and the remote UE can function as a remote UE in the first cell. Alternatively, if the measurement result value of the first cell (serving cell, primary cell, or camping cell) is greater than the threshold A, the remote UE is considered to not meet the threshold condition, and the remote UE does not meet the condition to serve as a remote UE in the first cell. The offset is, for example, hystMaxRemote.

[0119] If the remote UE can function as a remote UE in the first cell, the remote UE may use the first relay UE to connect to the first cell. However, if the value of the measurement result is greater than the threshold A, the remote UE has good signal quality when directly accessing the first cell. Therefore, the remote UE can access the first cell in a manner of directly connecting to the access network device.

[0120] Optionally, S206 may occur after the remote UE triggers relay reselection because the remote UE considers the signal on the sidelink to be insufficient. For example, if the remote UE finds that the sidelink quality (e.g., RSRP) is below threshold B, the remote UE is triggered to perform relay reselection. After the remote UE reselects the first relay UE, the remote UE is triggered to measure and determine the serving or camping cell of the reselected first relay UE. Optionally, if the sidelink quality (e.g., RSRP) of the remote UE and the first relay UE is greater than a certain threshold, the remote UE may not need to measure or determine the serving or camping cell of the first relay UE, thereby reducing power consumption.

[0121] Alternatively, optionally, S206 may occur after the remote UE finds that the signal quality (e.g., RSRP) of the sidelink is worse than a threshold C. For example, the remote UE finds that the sidelink quality (e.g., RSRP) is lower than a certain threshold C. In this case, relay reselection may not be triggered, and the remote UE may still measure and determine the serving cell or camping cell of the currently connected first relay UE. Optionally, if the sidelink quality (e.g., RSRP) of the remote UE and the first relay UE is greater than a certain threshold, the remote UE may not need to measure or determine the serving cell or camping cell of the relay UE, thereby reducing power consumption.

[0122] In this embodiment of the present application, the UE can obtain frequency information of the cell in which the relay UE is located, and can further determine the cell based on the frequency information and the cell's identifier. In this way, there is no need to perform blind search on multiple frequencies. This reduces the process of blindly searching the frequency and reduces the time required to search the cell. In addition, since the process of blindly searching the frequency is reduced, the power consumption of the UE is also reduced. In addition, the UE can further obtain the first information, or obtain the first information and the second information, so that the invalid search process of the UE can be reduced, and the power consumption can be further reduced.

[0123] Currently, when the remote UE is served in the RRC connected state, the remote UE may move or a link failure may occur. As a result, the quality of the connection between the remote UE and the access network device is deteriorated, and the service quality cannot be guaranteed. In this case, the access network device may switch the remote UE from a direct link between the remote UE and the access network device to an indirect link in which the remote UE is connected to the access network device using a relay UE. This switching process is also called a path switch. For example, when the connection quality of the Uu interface between the remote UE and the access network device is deteriorated, the access network device may configure a measurement object for the remote UE. The measurement object may include a Uu interface measurement object and a SL measurement object. The Uu interface measurement object may include, for example, Uu interface frequencies, and the remote UE may measure these frequencies on the Uu interface. The SL measurement object may include, for example, SL frequencies, and the remote UE may measure a relay UE operating on these frequencies in the sidelink. After completing the measurement, the remote UE can send the measurement result to the access network device. The measurement result may include Uu interface measurement result and SL measurement result. The access network device can determine whether the remote UE performs cell handover or switches from a direct link to an indirect link based on the measurement result.

[0124] When sending the SL measurement result to the access network device, the remote UE can further send the ID of the serving cell of the measured relay UE, and the access network device can determine the serving cell based on the ID of the serving cell. However, if the serving cell is not a cell provided by the access network device, the access network device cannot know the frequency of the serving cell. Generally, the serving cell of the relay UE is an FR2 high frequency cell (i.e., a cell having a frequency greater than 6 GHz), for example, the frequency of the serving cell is 28 GHz, or the serving cell is a cell operating in band n257. In this case, after the remote UE hands over to the relay UE, the bandwidth of the serving cell where the relay UE is located is large (usually 400 MHz), so the relay UE can obtain a higher data rate. Therefore, a remote UE with a large service volume is usually expected to be connected to a relay UE located in a serving cell with a high frequency. For example, the access network device determines that the remote UE switches to an indirect link based on the measurement result. In this case, the access network device can determine one relay UE. However, since the frequency of the serving cell of some relay UEs is unknown to the access network device, the access network device can only randomly select one relay UE from the relay UEs, and the frequency of the serving cell of the selected relay UE is very likely to be a low frequency. In the current solution, it can be found that the relay UE selected by the access network device cannot guarantee the data rate of the remote UE.

[0125] In another case, when the remote UE is served in the RRC connected state, because the service requirement of the remote UE is large, for example, the user needs to watch high definition video, the direct connection performed based only on the air interface or the transmission performed using only one relay UE is insufficient to help the user enjoy good service quality. Therefore, the remote UE also needs to find one relay UE that can provide a large data rate.

[0126] In view of this, an embodiment of the present application provides a second communication method. In this method, the access network device can configure the cell information or air interface frequency information that the relay UE needs to meet for the remote UE. In this way, the access network device can determine the cell information or air interface frequency information of the relay UE measured by the remote UE. In this way, when selecting a relay UE for the remote UE, the access network device can select a relay UE that meets the conditions as much as possible. For example, in order to improve the data rate of the remote UE, a relay UE located in a cell with a high frequency is selected. Figures 3A and 3B are flowcharts of the method.

[0127] S300: The remote UE transmits assistance information to the first access network device. In response, the first access network device receives assistance information from the remote UE. The assistance information can indicate that the remote UE expects to add a relay path. For example, if the remote UE expects to improve data rate or reliability, the remote UE can expect to add a relay path. Alternatively, the assistance information can indicate that the remote UE expects to switch to a relay path. For example, if the remote UE expects to reduce power consumption, the remote UE can expect to switch to a relay path.

[0128] S300 is an optional step. S300 may occur before the remote UE discovers the first relay UE, or may occur after the remote UE discovers the first relay UE.

[0129] S301: A first access network device transmits configuration information to a remote UE. Correspondingly, the remote UE receives configuration information from the first access network device. The first access network device is, for example, a serving access network device of the remote UE (e.g., the remote UE is in an RRC connected state), or an access network device on which the remote UE camps (e.g., the remote UE is in an RRC idle state or an RRC inactive state). The first access network device can transmit configuration information to the remote UE directly or using another relay device. Correspondingly, the remote UE can receive configuration information from the first access network device directly or using another relay device. In this embodiment of the present application, the remote UE can change the communication path. Therefore, the first access network device may also be referred to as a source access network device.

[0130] The configuration information can be used to configure an SL measuring object (MO). The SL measuring object includes, for example, a measurement frequency on the SL. One SL measuring object may be regarded as one SL measurement frequency, and the configuration information can be used to configure one or more SL measuring objects. The measurement frequency on the SL means that the remote UE is on the sidelink and can measure the relay UE operating on the measurement frequency. Optionally, the configuration information can be further used to configure cell information or Uu interface frequency information (or called air interface frequency information). The cell information is, for example, a cell in which the relay UE operating on the SL measuring object needs to operate or camp on, and the air interface frequency information is, for example, a frequency of a cell in which the relay UE operating on the SL measuring object needs to operate or camp on. When a UE is in an RRC connected state, the UE is considered to operate on the cell in which the UE is currently located, i.e., the serving cell of the UE. When a UE is in an RRC idle state or an RRC inactive state, the UE is considered to camp on the cell in which the UE is currently located. Optionally, the cell information includes, for example, an identifier of the cell. The identifier of the cell may include, for example, a PCI and / or an NCI of the cell, or may further include another identifier of the cell. The air interface frequency information includes, for example, information regarding the ARFCN or band.

[0131] The remote UE can select relay UEs that need to be measured based on the configuration information. For example, the SL measurement objects and cell information are configured based on the configuration information. In this case, the relay UEs that need to be measured by the remote UE include relay UEs that are on the sidelink, operate on the SL measurement objects, and camp on (or have operated) or can camp on (or can operate) the cell corresponding to the cell information. For example, the SL measurement objects configured based on the configuration information include frequency f1, and the cell information configured based on the configuration information includes cell c1. In this case, the remote UE can measure relay UEs that are on the sidelink, operate on frequency f1, and camp on (or have operated) the Uu interface or can camp on (or can operate) the cell c1. In another example, the SL measurement objects and air interface frequency information are configured based on the configuration information. In this case, the relay UEs that need to be measured by the remote UE include relay UEs that are on the sidelink, operate with SL measurement objects, and have camped (or operated) or can camp (or can operate) on a cell at a frequency corresponding to the air interface frequency information. For example, the SL measurement objects configured based on the configuration information include a frequency f1, and the air interface frequency information configured based on the configuration information includes a frequency f2. In this case, the remote UE can measure relay UEs that are on the sidelink, operate with a frequency f1, and have camped (or operated) on a Uu interface or can camp (or can operate) on a cell at a frequency f2.

[0132] In addition, optionally, the configuration information may be further used to configure an air interface measurement object (or referred to as a Uu interface measurement object). The air interface measurement object may, for example, include air interface frequency information, or include air interface frequency information and cell information. For distinction, the cell information included in the SL measurement object configured based on the configuration information may alternatively be referred to as first cell information, the air interface frequency information included in the SL measurement object may be referred to as first air interface frequency information, the cell information included in the air interface measurement object configured based on the configuration information may be referred to as second cell information, and the air interface frequency information included in the air interface measurement object may be referred to as second air interface frequency information. It should be noted that the first cell information and the first air interface frequency information are not used for measurements performed by the remote UE, i.e., the remote UE does not need to measure the first cell information or the first air interface frequency information on the air interface. Both the first cell information and the first air interface frequency information are used by the remote UE to select a relay UE that needs to be measured, or are used by the remote UE to select a relay UE that needs to send a measurement report to the first access network device. However, the second cell information and the second air interface frequency information are used by the remote UE to perform measurements, i.e., the remote UE may measure a cell corresponding to the second cell information or measure a cell at a frequency corresponding to the second air interface frequency information on the air interface.

[0133] The first access network device can determine a communication path for the remote UE based on the configuration information. For example, the communication path determined by the first access network device for the remote UE may be a single connectivity path. The single connectivity path is, for example, a direct connection path between the remote UE and the access network device. The access network device may be, for example, the first access network device or another access network device. In this case, the remote UE may need to perform a cell handover or may not need to perform a cell handover. Alternatively, the single connectivity path is, for example, a path in which the remote UE connects to the network using a relay UE. The remote UE is connected to the access network device in which the relay UE is located using a relay UE. The access network device may be, for example, the first access network device or another access network device. Alternatively, the communication path determined by the first access network device for the remote UE may be a dual connectivity or multi-connectivity path. A dual connectivity path is used as an example. The dual connectivity path includes, for example, two paths in which a remote UE is connected to two cells on an air interface separately, and the two cells may correspond to the same access network device or different access network devices. Alternatively, the dual connectivity path includes, for example, a path in which a remote UE is connected to a cell on an air interface, and further includes a path in which a remote UE is connected to a network using a relay UE, and the cell and the cell in which the relay UE is located may be the same cell or different cells. If the two cells are different cells, the two cells may correspond to the same access network device or different access network devices.Alternatively, the dual connectivity path may include a path in which the remote UE is separately connected to the network using two relay UEs, and the cells in which the two relay UEs are located may be the same cell or different cells. If the two cells are different cells, the two cells may correspond to the same access network device or different access network devices.

[0134] The first access network device can determine the communication path of the remote UE based on the configuration information in a corresponding manner. Hereinafter, a description will be provided based on S302 to S304.

[0135] S302: The remote UE measures a first type of relay UE based on the configuration information. Alternatively, S302 can be replaced as follows: The remote UE determines a first type of relay UE based on the configuration information, and measures the first type of relay UE.

[0136] The first type of relay UE is determined based on the configuration information. For example, the SL measurement object and the first cell information are configured based on the configuration information. In this case, the first type of relay UE may include a relay UE that operates with the SL measurement object and has camped (or operated) or can camp (or can operate) on a cell corresponding to the first cell information. For example, the SL measurement object configured based on the configuration information includes a frequency f1, and the first cell information configured based on the configuration information includes a cell c1. In this case, the first type of relay UE may include a relay UE that is on a sidelink, operates with a frequency f1, and has camped (or operated) on a Uu interface or can camp (or can operate) on the cell c1. A relay UE is not a first type relay UE if the relay UE meets one or more of the following conditions: the sidelink operating frequency of the relay UE is not an SL measurement object, the relay UE does not operate on the Uu interface and does not camp on the cell corresponding to the first cell information, or the relay UE cannot operate on the Uu interface and cannot camp on the cell corresponding to the first cell information.

[0137] Alternatively, the SL measurement object and the first air interface frequency information are configured based on the configuration information. In this case, the first type of relay UE may include a relay UE that operates with the SL measurement object and has camped (or operated) or can camp (or can operate) on a cell at a frequency corresponding to the first air interface frequency information. For example, the SL measurement object configured based on the configuration information includes a frequency f1, and the air interface frequency information configured based on the configuration information includes a frequency f2. In this case, the first type of relay UE may include a relay UE that is on a sidelink, operates with a frequency f1, and has camped (or operated) on a Uu interface or can camp (or can operate) on a cell at a frequency f2. A relay UE is not a first type relay UE if the relay UE meets one or more of the following conditions: the sidelink operating frequency of the relay UE is not an SL measurement object, the relay UE does not operate on the Uu interface and does not camp on a cell at a frequency corresponding to the first air interface frequency information, or the relay UE cannot operate on the Uu interface and cannot camp on a cell at a frequency corresponding to the first air interface frequency information.

[0138] After determining the first type of relay UE, the remote UE can measure the first type of relay UE. It should be noted that the remote UE can only measure the first type of relay UE, and does not measure another relay UE. Alternatively, the remote UE may further measure another relay UE in addition to measuring the first type of relay UE. This embodiment of the present application mainly describes the process of the remote UE measuring the first type of relay UE. If the remote UE needs to further measure another relay UE, the measurement process is similar.

[0139] To measure the relay UE, the remote UE needs to receive a message from the relay UE to complete the measurement based on the received message. Optionally, the measurement process of the remote UE may be implemented in different manners, which are described separately below. In the following description process, the process in which the remote UE measures one relay UE (e.g., referred to as the first relay UE) is used as an example.

[0140] 1. Method 1 In the first scheme, the first relay UE may transmit a message. For example, the message transmitted by the first relay UE is referred to as a fourth message. Please refer to S302a. Optionally, the fourth message may include information about the first frequency. The first frequency is, for example, a frequency of a cell in which the first relay UE is located, or a frequency of a cell in which the first relay UE can operate or camp on. The "first frequency" in this specification may alternatively be referred to as a "third frequency". Optionally, the information about the first frequency includes, for example, information about the ARFCN, band, etc. In addition, optionally, the fourth message may further include an identifier of the first relay UE, for example, the NCI and / or PCI of the first relay UE.

[0141] In the embodiment of the present application, when a UE is in an RRC connected state, the cell in which the UE is located is, for example, the serving cell of the UE, or the cell in which the UE operates. Alternatively, when a UE is in an RRC inactive state or an RRC idle state, the cell in which the UE is located is, for example, the cell in which the UE is camped. That is, the "operating cell" or "serving cell" corresponds to a UE in an RRC connected state, and the "camping cell" corresponds to a UE in an RRC inactive state or an RRC idle state.

[0142] The fourth message may be, for example, a discovery message or a PC5 RRC message. For a description of these messages, please refer to the embodiment shown in Figure 2. In S302a, an example is used in which the fourth message is a discovery message and includes information about the first frequency.

[0143] If the remote UE only measures relay UEs of the first type and does not measure relay UEs of another category, the remote UE may determine whether the first relay UE is a relay UE of the first type based on the configuration information. For example, if the first air interface frequency information is configured based on the configuration information and the first frequency belongs to a frequency corresponding to the first air interface frequency information, the first relay UE is a relay UE of the first type and the remote UE may measure the first relay UE. However, if the first frequency does not belong to a frequency corresponding to the first air interface frequency information, the first relay UE is not a relay UE of the first type and the remote UE may not measure the first relay UE. As another example, if the first cell information is configured based on the configuration information and the frequency of the first cell belongs to the first frequency (e.g., the frequency of the first cell is the first frequency, or the frequency of the first cell is included in the first frequency (e.g., the first frequency is a band)), the first relay UE is a first type of relay UE, and the remote UE can measure the first relay UE. However, if the frequency of the first cell belongs to the first frequency, the first relay UE is not a first type of relay UE, and the remote UE may not measure the first relay UE. When the remote UE needs to measure the first relay UE, optionally, the remote UE can complete the measurement of the first relay UE by measuring the fourth message. For example, the remote UE can measure the reference signal receiving power (RSRP), reference signal receiving quality (RSRQ), etc. of the fourth message.

[0144] Alternatively, when the remote UE can measure relay UEs of another category in addition to measuring the first type of relay UE, the remote UE can measure the first relay UE regardless of whether the first frequency belongs to a frequency corresponding to the first air interface frequency information, or regardless of whether the frequency of the first cell belongs to the first frequency.

[0145] 2. The second method In the second method, the remote UE may first send a message to the first relay UE. For example, the message sent by the remote UE is called the fifth message. After receiving the fifth message, the first relay UE may send a message, for example, called the sixth message, to the remote UE. The remote UE may perform measurements based on the sixth message. See S302b and S302c.

[0146] The fifth message may be used to inquire (or ask or request) frequency information of a cell in which the first relay UE is located, or may be used to inquire (or ask or request) frequency information of a cell in which the first relay UE can operate or camp on, or may be used to inquire (or ask or request) whether the first relay UE has camped on or can camp on a cell at the second frequency. If the fifth message is used to inquire whether the first relay UE has camped on or can camp on a cell at the second frequency, the first relay UE is considered to satisfy the condition inquired in the fifth message in all of the following cases: the first relay UE is camped on a cell at the second frequency, or the first relay UE is not currently camped on a cell at the second frequency but the first relay UE can camp on a cell at the second frequency, or the first relay UE is operating in a cell at the second frequency, or the first relay UE is not currently operating in a cell at the second frequency but the first relay UE can operate in a cell at the second frequency. The second frequency is, for example, a frequency corresponding to the first air interface frequency information. When multiple frequencies are configured based on the first air interface frequency information, the second frequency may include all or a part of the multiple frequencies. For example, a "second frequency" herein may alternatively be referred to as a "third frequency."

[0147] If the fifth message is used to inquire whether the first relay UE can operate or camp on a cell at a particular frequency, it indicates that the capability of the first relay UE is inquired. Even if the first relay UE is not currently operating or camping on a cell at that frequency, if the first relay UE has the capability to operate or camp on a cell at that frequency, the condition inquired in the fifth message is considered to be met. Alternatively, if the first relay UE is currently operating in or camping on a cell at that frequency, the condition inquired in the fifth message is also considered to be met. However, if the fifth message is used to inquire whether the first relay UE can operate in or camp on a cell at a particular frequency, it indicates that the cell in which the first relay UE is currently located is inquired. If the first relay UE is currently operating in or camping on a cell at that frequency, the condition inquired in the fifth message is considered to be met. However, if the first relay UE is not currently operating or camping on the cell on that frequency, it is considered that the condition queried in the fifth message is not met even if the first relay UE has the capability to operate or camp on the cell on that frequency.

[0148] If the fifth message is used to inquire about the frequency information of the cell in which the first relay UE is located, or the frequency information of the cell in which the first relay UE can operate or camp on, the fifth message may not include specific frequency information, and the remote UE may wait for a response from the first relay UE. In this way, the transmission overhead of the fifth message can be reduced.

[0149] Alternatively, when the fifth message is used to inquire whether the first relay UE has camped on or can camp on a cell in the second frequency, the fifth message may include information about the second frequency. The information about the second frequency is, for example, information about the ARFCN, the band, etc.

[0150] For the first relay UE, if the fifth message is used to inquire about frequency information of the cell in which the first relay UE is located, the sixth message may include frequency information of the cell in which the first relay UE is currently operating or camped.

[0151] Alternatively, when the fifth message is used to inquire about frequency information of a cell in which the first relay UE can operate or camp on, the sixth message may include frequency information of a cell in which the first relay UE can operate or camp on.

[0152] Alternatively, if the fifth message is used to inquire whether the first relay UE has camped on or can camp on a cell at the second frequency, the first relay UE may satisfy the condition inquired in the fifth message or may not satisfy the condition inquired in the fifth message. If the first relay UE has camped on, operated, can camp on, or can operate on a cell at the second frequency, the first relay UE satisfies the condition inquired in the fifth message. In this case, the sixth message may include information about the second frequency. Alternatively, the sixth message may indicate that the first relay UE is currently camped on or can camp on a cell at the second frequency. For example, in the sixth message, the indication is performed using one bit. If the value of the bit is "1", it indicates that the first relay UE is currently camped on or can camp on a cell at the second frequency. However, if the first relay UE is not currently camped on, not operating in, or unable to camp on a cell in the second frequency, the first relay UE does not meet the condition inquired in the fifth message. In this case, the first relay UE can still send a sixth message to the remote UE. The sixth message can, for example, include the frequency of the cell on which the first relay UE is camped or can camp on, or the sixth message can indicate that the first relay UE is not currently camped on and unable to camp on a cell in the second frequency. For example, in the sixth message, the indication is performed using one bit. If the value of the bit is "0", it indicates that the first relay UE is not currently camped on and unable to camp on a cell in the second frequency.Alternatively, if the first relay UE is not currently camped on, not operating in, or unable to camp on a cell in the second frequency, the first relay UE does not meet the condition inquired in the fifth message. In this case, the first relay UE may alternatively not send the sixth message to the remote UE, and thus the remote UE does not need to measure the first relay UE. In this way, the signaling overhead can be reduced, and the power consumption of the remote UE can also be reduced.

[0153] If the sixth message includes frequency information of a cell in which the first relay UE currently operates or camps, or if the sixth message includes frequency information of a cell in which the first relay UE can operate or camp, the frequency corresponding to the frequency information included in the sixth message may belong to the frequency corresponding to the first air interface frequency information. In this case, the first relay UE is a first type relay UE. Alternatively, the frequency corresponding to the frequency information included in the sixth message may not belong to the frequency corresponding to the first air interface frequency information. In this case, the first relay UE is not a first type relay UE. The remote UE can only measure the first type relay UE. If the first relay UE is a first type relay UE, the remote UE can measure the first relay UE. However, if the first relay UE is not a first type relay UE, the remote UE cannot measure the first relay UE. Alternatively, the remote UE may further measure another relay UE in addition to measuring the first type relay UE, in which case the remote UE can measure the first relay UE regardless of whether the first relay UE is the first type relay UE.

[0154] In S302b, an example is used in which the fifth message is a discovery message and includes information about the second frequency. In S302c, an example is used in which the sixth message is a discovery message and includes frequency information of a cell corresponding to the first relay UE. The cell corresponding to the first relay UE is, for example, a cell in which the first relay UE is currently operating or camping, or a cell in which the first relay UE can operate or camp.

[0155] S303: The remote UE transmits a measurement result to the first access network device. In response, the first access network device receives the measurement result from the remote UE. The measurement result is, for example, a measurement report. Alternatively, it is understood that the measurement result is included in the measurement report. The measurement result may be used to determine a communication path of the remote UE. For example, the first access network device can determine a communication path of the remote UE based on the measurement result.

[0156] If the remote UE measures only the first type of relay UE and does not measure another type of relay UE, the measurement result may include the measurement result of the first type of relay UE and not the measurement result of the other relay UE. Alternatively, if the remote UE measures another relay UE in addition to the first type of relay UE, the measurement result may still include only the measurement result of the first type of relay UE and not the measurement result of the other relay UE. In other words, even if the remote UE measures multiple types of relay UE, when sending the measurement result to the first access network device, the remote UE can only send the measurement result of the first type of relay UE, so that the measurement result reported by the remote UE meets the requirements of the first access network device, thereby reducing the transmission overhead.

[0157] Optionally, in addition to sending the measurement result to the first access network device, the remote UE may further send to the first access network device one or more pieces of information corresponding to the measurement result, such as an identifier of the relay UE, an identifier of the cell in which the relay UE is located, or a frequency of the relay UE on the Uu interface (e.g., the frequency of the cell in which the relay UE is located).

[0158] Optionally, if the remote UE further measures an air interface measurement object, the measurement result may further include an air interface measurement result, for example, a cell measurement result.

[0159] For example, the remote UE may send an RRC message to the first access network device. The measurement result may be included in the RRC message. One or more pieces of information, such as an identifier of the relay UE, an identifier of the cell in which the relay UE is located, or a frequency of the relay UE on the Uu interface, may also be included in the RRC message.

[0160] S304: The first access network device determines a communication path of the remote UE based on the measurement result.

[0161] For example, the first access network device may determine, based on the measurement result, that the communication path of the remote UE should be switched to connect to the network using a specific relay UE or should be handed over to another cell. In other words, the communication path determined by the first access network device for the remote UE is a single connectivity path. For example, if the measurement result indicates that the air interface measurement result is good, the first access network device may determine that the communication path of the remote UE should be switched to connect to the network using a specific relay UE. Alternatively, if the measurement result indicates that the SL measurement result is good, the first access network device may determine that the communication path of the remote UE should be switched to connect to the network using a specific relay UE. The relay UE is, for example, determined by the first access network device based on the measurement result. For example, the relay UE is a relay UE that has a good measurement result.

[0162] Optionally, regardless of whether the determined communication path of the remote UE is to handover to another cell or to switch to connect to the network using a specific relay UE, the first access network device can send a handover request message to the second access network device. The handover request message is, for example, a handover request. If the communication path of the remote UE is to handover to another cell, the second access network device is an access network device corresponding to a cell, the cell is, for example, a second cell, and the handover request message may be used to inquire (or ask, or request) whether the remote UE is to accept access to the second cell served by the second access network device. However, if the communication path of the remote UE switches to connect to the network using a specific relay UE, for example, the relay UE is a first relay UE, the second access network device is an access network device corresponding to the cell in which the relay UE operates or camps, the handover request message may be used to inquire (or ask or request) whether to accept the remote UE to be connected to the network using the first relay UE served by the second access network device. Optionally, the handover request message may further include information regarding the frequency to which the remote UE is expected to switch and / or the expected quality of service (QoS). The frequency to which the remote UE is expected to switch is, for example, the frequency of the second cell, or the frequency of the cell in which the first relay UE is located.

[0163] After receiving the handover request message, the second access network device can send a handover request response to the first access network device. The handover request response is, for example, an HO response. The handover request message is used to inquire whether the remote UE is allowed to access the second cell served by the second access network device, and if the second access network device can allow the remote UE to access the second cell served by the second access network device, the HO response is, for example, an HO acknowledgement (ACK) to indicate that the second access network device is allowed to allow the remote UE to access the second cell served by the second access network device. However, if the second access network device cannot accept the remote UE to access the second cell served by the second access network device, the HO response is, for example, an HO negative acknowledgement (NACK) to indicate that the second access network device does not accept the remote UE to access the second cell served by the second access network device. Alternatively, if the handover request message is used to inquire whether the remote UE is to be connected to the network using the first relay UE served by the second access network device, and the second access network device can accept the remote UE is to be connected to the network using the first relay UE served by the second access network device, the HO response is, for example, an HO ACK to indicate that the second access network device accepts the remote UE is to be connected to the network using the first relay UE served by the second access network device.Alternatively, if the second access network device cannot accept the remote UE to be connected to the network using the first relay UE served by the second access network device, the HO response is, for example, an HO NACK to indicate that the second access network device does not accept the remote UE to be connected to the network using the first relay UE served by the second access network device.

[0164] When the handover request response is an HO ACK, and the HO ACK indicates that the second access network device accepts the remote UE to be connected to the network using the first relay UE served by the second access network device, optionally, the handover request response may further include frequency information of the cell in which the first relay UE is located, and / or may include the PCI of the cell in which the first relay UE is located. For the first access network device, when the first air interface frequency information is configured for the remote UE in S301, the first access network device may verify whether the frequency corresponding to the frequency information of the cell in which the first relay UE is located belongs to the frequency corresponding to the first air interface frequency information. If the frequency corresponding to the frequency information of the cell in which the first relay UE is located belongs to the frequency corresponding to the first air interface frequency information, the remote UE may be connected to the network using the first relay UE. However, if the frequency corresponding to the frequency information of the cell in which the first relay UE is located does not belong to the frequency corresponding to the first air interface frequency information, the relay UE may need to be reselected or the communication path of the remote UE may be re-determined.

[0165] For example, if the handover request response is an HO ACK and the HO ACK indicates that the second access network device accepts the remote UE to be connected to the network using a first relay UE served by the second access network device, the handover request response may include frequency information of the cell in which the first relay UE is located or a cell on which the first relay UE can camp, and / or may include an ID, e.g., PCI / NCI, of the cell in which the first relay UE is located. However, all previous messages do not include frequency information of the cell in which the relay UE is located, nor frequency information of the cell on which the relay UE can camp (for example, in S301, the configuration information is not used to configure the first cell information and the first air interface frequency information. The fourth message does not include information on the first frequency, i.e., does not include frequency information of the cell in which the first relay UE is located. The fifth message does not inquire about frequency information of the cell in which the first relay UE is located, does not inquire about frequency information of the cell in which the first relay UE can operate or camp on, and does not inquire about whether the first relay UE has camped on or can camp on a cell at the second frequency. In addition, in S303, the remote UE may not send frequency information of the relay UE to the access network device over the Uu interface). In this case, it is equivalent to the following: the first access network device can select the first relay UE without knowing the frequency of the cell in which the first relay UE is located. The handover request response includes frequency information of the cell in which the first relay UE is located. The first access network device can determine whether the frequency information is the operating frequency or camping frequency of the relay UE on the air interface that the remote UE expects to access.If the frequency information is an operating frequency or camping frequency on the air interface that belongs to the relay UE that the remote UE expects to access, the first access network device can determine that the first relay UE is available, and the remote UE may be connected to the network using the first relay UE. However, if the frequency information is not an operating frequency or camping frequency on the air interface that belongs to the relay UE that the remote UE expects to access, the first access network device can reselect the remote UE or reselect a communication path for the remote UE. In this way, the frequency information does not need to be included in multiple messages, which helps to reduce signaling overhead.

[0166] Alternatively, the first access network device may determine, based on the measurement result, that the communication path of the remote UE includes an added path for connecting to the network using a specific relay UE, or an added direct connection path (e.g., an additional carrier aggregation (CA) / dual connectivity (DC) secondary cell), i.e., in addition to the current path, the communication path of the remote UE further includes an additionally added path. In other words, the communication path determined by the first access network device for the remote UE is a dual connectivity or multi-connectivity path. For example, if the quality of the current path of the remote UE is good and the first access network device further expects to increase the data rate of the remote UE, a multi-connectivity path may be configured for the remote UE. Alternatively, when the quality of the current route of the remote UE is poor and the remote UE needs to find a new route urgently, the first access network device can set up a single connectivity route of the remote UE, so that the remote UE is connected to the network as soon as possible. In this embodiment of the present application, dual connectivity is used as an example.

[0167] Whether the first access network device needs to add a secondary cell for the remote UE or a relay UE for the remote UE, the first access network device can also send a handover request message to the second access network device. Correspondingly, the second access network device can also send a handover request message to the first access network device. Please refer to the above description for this process.

[0168] Optionally, if the first access network device and the second access network device are the same access network device, the process of a handover request message and a handover request response may not need to be performed.

[0169] In addition, optionally, when the remote UE adds another communication path instead of switching the communication path in this embodiment of the present application, for example, when the first access network device needs to add a secondary cell or relay UE for the remote UE, the above process of handover request message and handover request response may not need to be performed. Optionally, the first access network device can alternatively perform a negotiation process with the second access network device. The process is similar to the handover request message and handover request response.

[0170] S305: The first access network device sends an RRC reconfiguration message to the remote UE. In response, the remote UE receives an RRC reconfiguration message from the first access network device.

[0171] If the communication path determined by the first access network device for the remote UE is to handover to a second cell served by a second access network device, the RRC reconfiguration message can instruct the remote UE to handover to the second cell. Alternatively, if the communication path determined by the first access network device for the remote UE is to switch to connect to a network using a first relay UE served by a second access network device, the RRC reconfiguration message can instruct the remote UE to handover to the first relay UE. Alternatively, if the communication path determined by the first access network device for the remote UE is to add a second cell served by a second access network device as a secondary cell, the RRC reconfiguration message can instruct the remote UE to add the second cell as a secondary cell. Alternatively, if the communication path determined by the first access network device for the remote UE is to add a path for connecting to a network using a first relay UE served by a second access network device, the RRC reconfiguration message may instruct the remote UE to add a path for connecting to a network using the first relay UE.

[0172] Optionally, when the RRC reconfiguration message instructs the remote UE to handover to the first relay UE or instructs the remote UE to add a path for connecting to the network using the first relay UE, the RRC reconfiguration message may include one or more of an identifier of the first relay UE, an identifier of the cell in which the first relay UE is located, or a cell-radio network temporary identifier (C-RNTI) of the first relay UE. The identifier of the cell in which the first relay UE is located includes, for example, the NCI and / or PCI of the cell. For example, the handover request response includes the PCI of the cell in which the first relay UE is located. In this case, optionally, the RRC reconfiguration message includes the PCI of the cell in which the first relay UE is located. This is equivalent to the following: The PCI of the cell in which the first relay UE is located and stored in the second access network device may be transferred to the remote UE.

[0173] S306: The remote UE establishes a connection to the first relay UE, where the connection is, for example, a unicast connection.

[0174] If the RRC reconfiguration message instructs the remote UE to handover to the first relay UE or instructs the remote UE to add a path to connect to the network using the first relay UE, the remote UE can perform S306 and subsequent steps. However, if the RRC reconfiguration message instructs the remote UE to handover to the second cell or instructs the remote UE to add the second cell as a secondary cell, the remote UE does not need to perform S306 and subsequent steps. For example, the remote UE can access the second cell. This embodiment of the present application mainly describes the case where the remote UE hands over to the first relay UE or the first relay UE is added.

[0175] In addition, if the remote UE has established a connection with the first relay UE, S306 may not need to be performed.

[0176] Optionally, after the remote UE establishes a connection to the first relay UE, the first relay UE can send the PCI of the cell in which the first relay UE is located to the remote UE. In this case, the RRC reconfiguration message in S305 may or may not include the PCI of the cell in which the first relay UE is located. In other words, the remote UE can obtain the PCI of the cell in which the first relay UE is located in multiple ways. For example, the PCI is sent to the remote UE by the first relay UE, or is sent to the remote UE by an access network device (e.g., a second access network device).

[0177] The first relay UE may only camp on a cell configured based on the configuration information, but may not currently camp on a cell, or the first relay UE may only camp on a cell at a frequency configured based on the configuration information, but may not currently camp on a cell at that frequency. Therefore, optionally, after establishing a connection to the first relay UE, the remote UE may further send first indication information to the first relay UE. The first indication information instructs the first relay UE to reselect a cell corresponding to the cell information configured based on the configuration information, or instructs the first relay device to reselect a cell at a frequency corresponding to the air interface frequency information configured based on the configuration information. The first relay UE may reselect a corresponding cell based on the first indication information to provide relay service to the remote UE.

[0178] S307: The second access network device sends an RRC reconfiguration message to the first relay UE. In response, the first relay UE receives an RRC reconfiguration message from the second access network device. For distinction, the RRC reconfiguration message of S305 may alternatively be referred to as a first RRC reconfiguration message, and the RRC reconfiguration message of S307 may alternatively be referred to as a second RRC reconfiguration message.

[0179] The second RRC reconfiguration message may be used to configure the first relay UE, so that the remote UE may connect to the network using the first relay UE.

[0180] Optionally, when the first access network device and the second access network device are the same access network device, S307 can be replaced as follows: the first access network device sends an RRC reconfiguration message to the first relay UE. Correspondingly, the first relay UE receives an RRC reconfiguration message from the first access network device.

[0181] S308: The first relay UE sends an RRC reconfiguration complete message to the second access network device. In response, the second access network device receives an RRC reconfiguration complete message from the first relay UE. After completing the configuration based on the second RRC reconfiguration message, the first relay UE can execute S308. S307 and S308 indicate the information exchange between the first relay UE and the access network device after the first relay UE enters the RRC connected state.

[0182] Optionally, when the first access network device and the second access network device are the same access network device, S308 can be replaced as follows: the first relay UE sends an RRC reconfiguration complete message to the first access network device. Correspondingly, the first access network device receives an RRC reconfiguration complete message from the first relay UE. For example, the RRC reconfiguration complete message in S308 is called a second RRC reconfiguration complete message.

[0183] S309: The remote UE sends an RRC reconfiguration complete message. For example, the remote UE sends an RRC reconfiguration message to a first relay UE, and the first relay UE receives an RRC reconfiguration complete message from the remote UE. Then, the first relay UE sends an RRC reconfiguration complete message to a second access network device, and the second access network device receives an RRC reconfiguration message from the first relay UE. For example, the RRC reconfiguration complete message in S309 is called a first RRC reconfiguration complete message.

[0184] For example, if the route of the first relay UE is a route added by the first access network device for the remote UE, after a connection between the first relay UE and the second access network device is successfully established (e.g., the first relay UE successfully randomly accesses the second network device, or timer T300 or timer T301 stops, or the first relay UE enters an RRC connected state), and after the remote UE receives an indication from the first relay UE, the remote UE may send a first RRC reconfiguration complete message to the first access network device.

[0185] Optionally, when the first access network device and the second access network device are the same access network device, in S309, the remote UE sends a first RRC reconfiguration complete message to the first relay UE, and the first relay UE receives the first RRC reconfiguration complete message from the remote UE.Then, the first relay UE sends a first RRC reconfiguration complete message to the first access network device, and the first access network device receives the first RRC reconfiguration message from the first relay UE.Alternatively, after receiving a message that the first relay UE is successfully accessed, the remote UE sends a first RRC reconfiguration complete message to the first access network device.

[0186] After the remote UE establishes a connection with the first relay UE, if the first relay UE is in an RRC idle state or an RRC inactive state, optionally, after receiving a first RRC reconfiguration complete message from the remote UE, the first relay UE may be triggered to enter an RRC connected state and access a second access network device. Alternatively, the second access network device may be referred to as a target network device. Thus, step S309 in which the remote UE sends a first RRC reconfiguration complete message to the first relay UE may occur before S307 or may occur after S307.

[0187] The first relay UE does not analyze the first RRC reconfiguration complete message from the remote UE. In this case, the first relay UE may be triggered to enter the RRC connected state in multiple ways.

[0188] Since the first relay UE knows the PC5 radio link control (RLC) configuration of the first RRC reconfiguration complete message (e.g., the PC5 RLC configuration is a default PC5 RLC configuration or is configured by the remote UE using a PC5 RRC message), the first relay UE can determine whether the first relay UE needs to be triggered to enter an RRC connected state based on whether there is a specific PC5 LCID or based on a data packet received on the SL RLC bearer, i.e., based on whether a logical channel ID (LCID) in the RRC reconfiguration complete message is sent or based on whether a data packet is received on the SL RLC bearer. For example, when the first relay UE is in the RRC idle state, if the first relay UE receives any message sent via SL-RLC 1 (sidelink RLC 1, an RLC channel used to transmit the remote UE's SRB 1 on the sidelink) from the L2 U2N (UE to network) remote UE, the RRC layer of the first relay UE can initiate an RRC connection establishment process to enter the RRC connected state. As another example, when the first relay UE is in the RRC inactive state, if the first relay UE receives any message sent via SL-RLC 1 (sidelink RLC 1, an RLC channel used to transmit the remote UE's SRB 1 on the sidelink) from the L2 U2N remote UE, the RRC layer of the first relay UE can initiate an RRC connection resumption process to enter the RRC connected state.

[0189] However, since the first relay UE receives the message over SL-RLC and does not send the message to the RRC layer of the first relay UE for parsing, the RRC layer of the first relay UE requires the bottom layer of the first relay UE to inform the RRC layer of the first relay UE whether the SL-RLC receives the data packet.

[0190] In one possible scheme, if the RRC layer of the first relay UE determines that the first relay UE is in an RRC idle state or an RRC inactive state and receives an indication that the MAC layer or the RLC layer receives a data packet on a specific LCID, the RRC layer can determine that the conditions for the first relay UE to enter an RRC connected state are met. In this case, the RRC layer can notify a non-access stratum (NAS) of the first relay UE that the first relay UE needs to enter an RRC connected state. The NAS delivers an indication to the RRC layer to trigger the RRC layer to initiate an RRC connection establishment process or an RRC connection resumption process to enter an RRC connected state.

[0191] For example, when the MAC layer receives a MAC service data unit (SDU) on a logical channel with source L2 ID equal to X and LCID (LCID is the LCID of the logical channel carrying the first RRC reconfiguration complete message) equal to 1, if the MAC SDU is the first MAC SDU received on the logical channel with source L2 ID equal to X and LCID equal to 1, the MAC layer determines whether data has been previously received on a logical channel with source L2 ID equal to X and LCID (LCID is the ID of the logical channel carrying the RRC connection establishment request message or the RRC connection resume request message) equal to 0. If no data is received, an indication is sent to the RRC layer to instruct the MAC layer to receive a data packet on the particular LCID.

[0192] In another example, when an RLC bearer (e.g., SL-RLC 1) corresponding to an LCID equal to 1 (the LCID carrying the RRC reconfiguration complete message) receives an RLC protocol data unit (PDU), if the RLC PDU is the first RLC PDU received on the RLC bearer, the RLC layer may send an indication to the RRC layer to indicate that the RLC layer has received a data packet on the particular LCID.

[0193] In another possible manner, when the RRC layer of the first relay UE determines that the relay UE is in an RRC inactive state and receives an indication that the MAC layer or the RLC layer receives a data packet on a specific LCID, the RRC layer determines that the condition for the first relay UE to enter an RRC connected state is met. In this case, the RRC layer can initiate an RRC connection resumption process to trigger entering the RRC connected state.

[0194] For example, when the MAC layer receives a MAC SDU on a logical channel with source L2 ID equal to X and LCID (LCID carrying an RRC reconfiguration complete message) equal to 1, if the MAC SDU is the first MAC SDU received on the logical channel with source L2 ID equal to X and LCID equal to 1, the MAC layer determines whether data has been previously received on a logical channel with source L2 ID equal to X and LCID (carrying an RRC connection establishment request message or an RRC connection resume request message) equal to 0. If no data has been received, an indication is sent to the RRC layer to instruct the MAC layer to receive a data packet on the particular LCID.

[0195] In another example, when an RLC bearer (e.g., SL-RLC 1) corresponding to an LCID equal to 1 (the LCID carrying the RRC reconfiguration complete message) receives an RLC PDU, if the RLC PDU is the first RLC PDU received on the RLC bearer, the RLC layer may send an indication to the RRC layer to indicate that the RLC layer has received a data packet on the particular LCID.

[0196] The process of determining whether the RRC layer of the first relay UE enters the RRC connected state may also be applicable to a relay UE in an RRC idle state or an RRC inactive state. For example, after receiving a connection establishment request message from a remote UE in an RRC idle state or receiving a connection resumption request message from a remote UE in an RRC inactive state, the UE in an RRC idle state or an RRC inactive state can determine whether to enter the RRC connected state in the above-mentioned manner.

[0197] In this case, the remote UE may be connected to the network using the first relay UE. When the remote UE switches to a path, the remote UE needs to be disconnected from the original communication path. For example, the remote UE needs to release the connection to the first access network device. However, when the remote UE adds a path, the remote UE does not need to be disconnected from the original communication path. For example, the remote UE may be directly connected to the first access network device or may be connected to the network using the first relay UE, thereby improving the throughput rate of the remote UE.

[0198] Any of S305 to S309 is an optional step.

[0199] In this embodiment of the present application, the first access network device can learn frequency information of the cell in which the relay UE is located, so that the first access network device can select a more suitable relay UE when selecting a relay UE for the remote UE. For example, the first access network device can select a relay UE that operates at a high frequency on the air interface for the remote UE, so that the data rate of the remote UE can be improved. In addition, the remote UE may perform communication via a single connectivity communication path or may perform communication via a multi-connectivity communication path. This helps to improve the communication flexibility of the remote UE and also improve the throughput rate of the remote UE.

[0200] The embodiment shown in FIG. 3A and FIG. 3B relates to a measurement process performed by a remote UE. For example, the remote UE may measure a measurement object on a Uu interface, or may measure a measurement object (or an SL measurement object) on a PC5 interface. If the remote UE starts two measurement processes simultaneously, the power consumption of the remote UE is high. If the access network device configures the remote UE to perform only one of the measurement processes, the measurement results obtained by the remote UE may not meet the reporting condition, or the measurement results meet the reporting condition but all the measurement results are insufficient. In this case, the access network device may further need to configure the remote UE to perform another measurement process. In this way, the measurement delay caused thereby is large. Therefore, an embodiment of the present application provides a third communication method. In this method, the remote UE can perform measurements according to a corresponding policy, so that the case where the power consumption is excessively high because two measurement processes need to be started simultaneously is avoided, and the case where the measurement delay is excessively high because only one measurement process can be performed is also avoided. 4A and 4B are a flow chart of the method.

[0201] S400: A remote UE sends assistance information to a first access network device. In response, the first access network device receives assistance information from the remote UE.

[0202] S400 is an optional step. For more details of S400, such as the description of the support information, please refer to S300 in the embodiment shown in FIG. 3A.

[0203] S401: An access network device sends configuration information to a remote UE. In response, the remote UE receives configuration information from the access network device.

[0204] The configuration information may be used to configure the measurement objects. For example, the configuration information may be used to configure a first type of measurement object and a second type of measurement object. A communication path corresponding to the first type of measurement object belonging to the remote UE is different from a communication path corresponding to the second type of measurement object belonging to the remote UE. For example, the first type of measurement object is a Uu interface measurement object (or an air interface measurement object), and the second type of measurement object is an SL measurement object (or a PC5 interface measurement object). In another example, the second type of measurement object is a Uu interface measurement object, and the first type of measurement object is an SL measurement object. A communication path corresponding to the Uu interface measurement object belonging to the remote UE is a Uu interface communication path, and a communication path corresponding to the SL measurement object belonging to the remote UE is an SL. It may be found that the communication paths corresponding to the two types of measurement objects belonging to the remote UE are different.

[0205] The SL measurement object includes, for example, an SL measurement frequency. The air interface measurement object includes, for example, an air interface measurement frequency (or includes air interface measurement frequency and cell information, and the air interface measurement frequency is used as an example in this embodiment of the present application). The configuration information may be used to configure one or more SL measurement objects, or may be used to configure one or more air interface measurement objects. Optionally, the SL measurement object may be associated with the air interface measurement object. For example, one air interface measurement frequency configured based on the configuration information may be associated with some or all of the SL measurement frequencies configured based on the configuration information. The association of one air interface measurement frequency with one SL measurement frequency means that the relay UE to be measured needs to operate or camp on the air interface measurement frequency on the Uu interface, and the relay UE needs to operate on the SL measurement frequency on the PC5 interface.

[0206] In addition, optionally, the configuration information may further include a first threshold value, for example, a threshold value corresponding to a first type of measurement object or a measurement result of the first type of measurement object.

[0207] S402: The remote UE measures a first type measurement object based on the configuration information.

[0208] For example, M first-type measurement objects and N second-type measurement objects are configured based on the configuration information, where both M and N are positive integers. If the first-type measurement objects are, for example, air interface measurement objects, the remote UE may measure the M air interface measurement objects configured based on the configuration information. Alternatively, if the first-type measurement objects are, for example, SL measurement objects, the remote UE may measure the N SL measurement objects configured based on the configuration information.

[0209] S403: If the measurement result of the first type of measurement object does not satisfy the first condition, the remote UE measures the second type of measurement object, or in other words, the remote UE starts measuring the second type of measurement object. Alternatively, if the measurement result of the first type of measurement object satisfies the first condition, the remote UE may not measure the second type of measurement object, or in other words, the remote UE may not start measuring the second type of measurement object.

[0210] Both S402 and S403 in FIG. 4A cover the first relay UE. This only represents that the remote UE measures the relay UE, and does not mean that the first relay UE is included in both the measurement process of the first type of measurement object and the measurement process of the second type of measurement object. It can be understood as follows: the first relay UE may be included in both the measurement process of the first type of measurement object and the measurement process of the second type of measurement object. Or, the first relay UE is included in the measurement process of the first type of measurement object but is not included in the measurement process of the second type of measurement object. Or, the first relay UE is included in the measurement process of the second type of measurement object but is not included in the measurement process of the first type of measurement object.

[0211] There may be different judgment methods for judging whether the measurement result of the first type of measurement object satisfies the first condition. For example, in one judgment manner, if none of the measurement results of the M measurement objects configured based on the configuration information satisfies the first condition, the measurement result of the first type of measurement object is deemed to not satisfy the first condition. However, if any one of the measurement results of the M measurement objects satisfies the first condition, the measurement result of the first type of measurement object is deemed to satisfy the first condition. In this case, the remote UE can start measuring the N second type of measurement objects. This is equivalent to the following: After measuring all the M measurement objects, the remote UE can judge whether to start the measurement process of the second type of measurement object.

[0212] Alternatively, in another determination manner, M measurement objects are measured and determined separately. For example, one measurement object (e.g., referred to as a measurement result of a first measurement object) among the M measurement objects satisfies a first condition. In this case, the measurement result of the first type measurement object is considered to satisfy the first condition, and the remote UE can continue to measure the next measurement object among the M measurement objects, e.g., the next measurement object, referred to as a second measurement object. However, if the measurement result of the first measurement object does not satisfy the first condition, the measurement result of the first type measurement object is considered not to satisfy the first condition. In this case, the remote UE can start measuring the second type measurement object. The second type measurement objects measured by the remote UE in this case are, for example, K second type measurement objects having an association relationship with the first measurement object. The remote UE may not measure N to K second type measurement objects temporarily, where K is a positive integer equal to or less than N. For example, after measuring K second-type measurement objects, the remote UE can measure the next measurement object among the M measurement objects again, for example, the second measurement object, and determine whether the measurement result of the second measurement object satisfies the first condition. The rest is deduced by analogy. This is equivalent to the following: the remote UE performs a determination for each first-type measurement object separately to determine whether to start measuring the second-type measurement object corresponding to the first-type measurement object.

[0213] For example, the first type of measurement object is an air interface measurement object, the second type of measurement object is an SL measurement object, the M measurement objects are M air interface frequencies, and the N measurement objects are N SL frequencies. The remote UE may measure a cell at a first air interface frequency among the M air interface frequencies. If the measurement result of any cell at the first air interface frequency satisfies the first condition, the remote UE may consider the measurement result of the first air interface frequency to satisfy the first condition, and the remote UE may continue measuring the next air interface frequency (e.g., the second air interface frequency) among the M air interface frequencies. However, if none of the measurement results of all cells that can be measured at the first air interface frequency satisfies the first condition, the remote UE may consider the measurement result of the first air interface frequency to not satisfy the first condition, and the remote UE may measure the SL frequencies within the N SL frequencies associated with the first air interface frequency, i.e., measure relay UEs operating at these SL frequencies and on the sidelink. After measuring these SL frequencies, the remote UE may start measuring the next air interface frequency (eg, the second air interface frequency) in the M air interface frequencies. The rest are deduced by analogy.

[0214] In another example, the first type of measurement object is an SL measurement object, the second type of measurement object is an air interface measurement object, the M measurement objects are M SL frequencies, and the N measurement objects are N air interface frequencies. The remote UE may measure an SL frequency associated with a first air interface frequency among the M air interface frequencies. For example, these SL frequencies may be referred to as first SL frequencies, and the first SL frequencies may include one or more SL frequencies. If any relay UE's measurement results at the first SL frequency satisfy the first condition, the remote UE may consider the measurement results at the first SL frequency to satisfy the first condition, and the remote UE may continue measuring the SL frequency for a next air interface frequency (e.g., a second air interface frequency) among the M air interface frequencies. However, if none of the measurement results of all relay UEs that can be measured at the first SL frequency meets the first condition, the remote UE considers that the measurement result of the first SL frequency does not meet the first condition, and the remote UE can measure the first air interface frequency, i.e., measure the cell at the first air interface frequency. After measuring the first air interface frequency, the remote UE may start measuring the SL frequency for the next air interface frequency (e.g., the second air interface frequency) in the M air interface frequencies. The rest is deduced by analogy.

[0215] Optionally, whether the measurement result of one first type of measurement object satisfies the first condition is, for example, whether the value of the measurement result is less than a first threshold. If the value of the measurement result is less than the first threshold, the measurement result is considered not to satisfy the first condition. However, if the value of the measurement result is equal to or greater than the first threshold, the measurement result is considered to satisfy the first condition. Alternatively, in addition to this implementation, the first condition may further have another implementation. This is not specifically limited.

[0216] It should be noted that the measurement result of one first type of measurement object may include one or more measurement results. For example, the measurement object of the first type is an air interface measurement object. The first measurement object is used as an example. The first measurement object may be, for example, an air interface frequency, and the measurement result of the first measurement object may include the measurement result of one or more cells at the air interface frequency, that is, the measurement result of the first measurement object may include one or more measurement results. In this case, if one of the one or more measurement results of the first measurement object satisfies the first condition (e.g., the value of the measurement result is equal to or greater than the first threshold), the measurement result of the first measurement object is considered to satisfy the first condition. However, if none of the one or more measurement results of the first measurement object satisfies the first condition (e.g., the value of each measurement result in the multiple measurement results is less than the first threshold), the measurement result of the first measurement object is considered not to satisfy the first condition.

[0217] In another example, the first type of measurement object is an SL measurement object. For example, one first type of measurement object is an SL frequency. In this case, the measurement result of the SL frequency may also include the measurement result of one or more relay UEs operating on the SL frequency and on the sidelink, i.e., the measurement result of the SL frequency may also include one or more measurement results. In this case, if one of the one or more measurement results of the SL frequency satisfies the first condition, the measurement result of the SL frequency is considered to satisfy the first condition. However, if none of the one or more measurement results of the SL frequency satisfies the first condition, the measurement result of the SL frequency is considered to not satisfy the first condition.

[0218] As can be seen from the above, if the measurement result of the first type of measurement object satisfies the first condition, the remote UE may not measure the second type of measurement object. However, if the measurement result of the first type of measurement object does not satisfy the first condition, the remote UE may measure the second type of measurement object.

[0219] S404: The remote UE sends a measurement result to the access network device. In response, the access network device receives the measurement result from the remote UE.

[0220] If the remote UE does not initiate a measurement process of the second type of measurement object, the measurement result acquired by the remote UE includes the measurement result of the first type of measurement object, and the measurement result transmitted by the remote UE to the access network device also includes the measurement result of the first type of measurement object. Alternatively, if the remote UE initiates a measurement process of the second type of object, the measurement result acquired by the remote UE may include the measurement result of the first type of measurement object and the measurement result of the second type of measurement object, and the measurement result transmitted by the remote UE to the access network device may include the measurement result of the first type of measurement object and / or the measurement result of the second type of measurement object. The remote UE determines whether a measurement result reporting condition is met based on whether a measurement event is triggered, and determines whether the remote UE transmits the measurement result to the access network device. The measurement result may include all or a part of the measurement result acquired by the remote UE.

[0221] S405: The access network device determines a communication path of the remote UE based on the measurement result. A second access network device may be involved in S405. Therefore, the access network device that performs S401 to S405 may alternatively be referred to as a first access network device.

[0222] For more details about S405, please refer to S304 in the embodiment shown in FIG. 3A.

[0223] S406: The first access network device sends an RRC reconfiguration message to the remote UE. In response, the remote UE receives an RRC reconfiguration message from the first access network device.

[0224] For more details about S406, please refer to S305 in the embodiment shown in FIG. 3B.

[0225] S407: The remote UE establishes a connection to the first relay UE, where the connection is, for example, a unicast connection.

[0226] For more details about S407, please refer to S306 in the embodiment shown in FIG. 3B.

[0227] S408: The second access network device sends an RRC reconfiguration message to the first relay UE. In response, the first relay UE receives an RRC reconfiguration message from the second access network device. For distinction, the RRC reconfiguration message of S406 may alternatively be referred to as a first RRC reconfiguration message, and the RRC reconfiguration message of S408 may alternatively be referred to as a second RRC reconfiguration message.

[0228] The second RRC reconfiguration message may be used to configure the first relay UE, so that the remote UE may connect to the network using the first relay UE.

[0229] S409: The first relay UE sends a second RRC reconfiguration complete message to the second access network device. In response, the second access network device receives a second RRC reconfiguration complete message from the first relay UE. After completing the configuration based on the second RRC reconfiguration message, the first relay UE can execute S409. S408 and S409 indicate the information exchange between the first relay UE and the access network device after the first relay UE enters the RRC connected state.

[0230] S410: The remote UE sends a first RRC reconfiguration complete message. For example, the remote UE sends a first RRC reconfiguration message to a first relay UE, and the first relay UE receives the first RRC reconfiguration complete message from the remote UE. Then, the first relay UE sends a first RRC reconfiguration complete message to a second access network device, and the second access network device receives the first RRC reconfiguration message from the first relay UE.

[0231] In another example, if the route of the first relay UE is a route added by the first access network device for the remote UE, after a connection between the first relay UE and the second access network device is successfully established (e.g., the first relay UE successfully randomly accesses the second network device, or timer T300 or timer T301 stops, or the first relay UE enters an RRC connected state), and after the remote UE receives an indication from the first relay UE, the remote UE may send a first RRC reconfiguration complete message to the first access network device.

[0232] Similarly, the first access network device and the second access network device may be different access network devices or may be the same access network device. If the first access network device and the second access network device are the same access network device, please refer to S307-S309 in the embodiment shown in Figure 3B for the implementation form of S408-S410.

[0233] S404 to S410 are all optional steps.

[0234] In this embodiment of the present application, the access network device can configure two types of measurement objects, but the remote UE determines the specific type of measurement object to be measured based on the first condition. In this case, the remote UE does not need to measure both of the two types of measurement objects, thereby reducing power consumption. In addition, the access network device does not need to configure the measurement objects separately, and the remote UE can determine the specific type of measurement object to be measured, thereby reducing measurement delay.

[0235] The access network device may have an expectation for a particular type of communication path selected for the remote UE. For example, the access network device may expect the remote UE to select a path directly connected to the access network device, or may expect the remote UE to select a path connected using a relay UE. However, when transmitting measurement results to the access network device, the remote UE may transmit two types of measurement results (Uu interface measurement results and SL measurement results). For the access network device, some measurement results may be redundant. In addition, transmission overhead is wasted. Therefore, an embodiment of the present application provides a fourth communication method. According to this method, the remote UE can properly transmit the measurement results to the access network device, so that the transmitted measurement results better meet the requirements of the access network device. This reduces the transmission overhead. Figure 5 is a flowchart of the method.

[0236] S500: A remote UE sends assistance information to a first access network device. In response, the first access network device receives assistance information from the remote UE.

[0237] S500 is an optional step. For more details of S500, such as the interpretation of the support information, please refer to S300 in the embodiment shown in FIG. 3A.

[0238] S501: An access network device sends configuration information to a remote UE. In response, the remote UE receives configuration information from the access network device.

[0239] The configuration information may be used to configure a measurement event. For example, a measurement event configured based on the configuration information includes that a value of a measurement result of a first type of measurement object is less than a first threshold and a value of a measurement result of a second type of measurement object is greater than or equal to a second threshold. This is equivalent to: one type of measurement event is configured based on the configuration information. When a measurement event is triggered, the remote UE sends the measurement result in the measurement event to the access network device.

[0240] In another example, the measurement event configured based on the configuration information includes multiple types of measurement events, for example, a first measurement event, a second measurement event, and a third measurement event. The first measurement event includes that a value of a measurement result of a first type of measurement object is less than a first threshold. The second measurement event includes that a value of a measurement result of a second type of measurement object is equal to or greater than a second threshold. The third measurement event includes that a value of a measurement result of a first type of measurement object is equal to or greater than a first threshold. This is equivalent to the following: the configuration information may be used to configure multiple measurement events, and for a measurement result that satisfies any one of the measurement events, if a measurement event is triggered, the remote UE may transmit the measurement result to the access network device. In other words, when a first measurement event is configured for a first measurement object, if a value of a measurement result of the first measurement object is less than a first threshold, a measurement event is triggered and the remote UE can report the measurement result to the access network device, and the first measurement object is a first type of measurement object. When a second measurement event is configured for a second measurement object, if a value of the measurement result of the second measurement object is greater than or equal to a second threshold, a measurement event is triggered and the remote UE can send the measurement result to the access network device, and the second measurement object is a second type of measurement object. When a third measurement event is configured for a third measurement object, if a value of the measurement result of the third measurement object is greater than or equal to the first threshold, a measurement event is triggered and the remote UE can send the measurement result to the access network device, and the third measurement object is a first type of measurement object.

[0241] Optionally, the configuration information may be further used to configure the measurement object. For example, the configuration information may be used to configure a first type of measurement object and a second type of measurement object. The first type of measurement object configured based on the configuration information includes, for example, M measurement objects, and the second type of measurement object configured based on the configuration information includes, for example, N measurement objects. In addition, there may be an association relationship between the first type of measurement object and the second type of measurement object. For this part of the content, please refer to S401 of the embodiment shown in FIG. 4A.

[0242] S502: The remote UE measures a first type measurement object and a second type measurement object.

[0243] For example, M measurement objects and N measurement objects are configured based on the configuration information, in which case the remote UE can measure the M measurement objects and measure the N measurement objects.

[0244] S503: The remote UE sends a measurement result to the access network device according to the measurement event configured according to the configuration information. Correspondingly, the access network device receives a measurement result from the remote UE. The measurement result includes, for example, a measurement result of a first type measurement object and / or a measurement result of a second type measurement object.

[0245] 1. The measurement event is configured based on the configuration information, i.e., the value of the measurement result of a first type of measurand is less than a first threshold and the value of the measurement result of a second type of measurand is greater than or equal to a second threshold. For example, the first threshold and / or the second threshold are predefined in a protocol or configured by the access network device.

[0246] The remote UE may perform a decision on the acquired measurement results to decide whether to send the measurement results to the access network device, or to decide a particular measurement result to be sent to the access network device. For example, if the value of the measurement result of the first type of measurement object is smaller than a first threshold and the value of the measurement result of the second type of measurement object is equal to or larger than a second threshold, in this case, the measurement result of the second type of measurement object is good, but the measurement result of the first type of measurement object is bad, and even if the measurement result of the first type of measurement object is sent to the access network device, it is unlikely that the access network device can select a communication path corresponding to the first type of measurement object for the remote UE. Therefore, the remote UE may send the measurement result of the second type of measurement object to the access network device, but not send the measurement result of the first type of measurement object.

[0247] Alternatively, if the value of the measurement result of the first type of measurement object is equal to or greater than the first threshold, then the measurement result of the first type of measurement object is good. For example, the communication path corresponding to the first type of measurement object is the communication path that the access network device expects to select for the remote UE. Therefore, regardless of whether the value of the measurement result of the second type of measurement object is equal to or greater than the second threshold, the remote UE can transmit the measurement result of the first type of measurement object to the access network device and does not need to transmit the measurement result of the second type of measurement object.

[0248] Alternatively, if the value of the measurement result of the first type of measurement object is less than the first threshold and the value of the measurement result of the second type of measurement object is less than the second threshold, it indicates that the measurement results of the two measurement objects are both insufficient, and the access network device is likely not able to determine the communication path of the remote UE from the measurement results. Therefore, the remote UE may not send the measurement result to the access network device, and neither the measurement result of the first type of measurement object nor the measurement result of the second type of measurement object is sent, i.e., S503 is not executed.

[0249] Optionally, the first type of measurand and the second type of measurand under the measurement conditions may not have an association relationship, or it is understood as follows: whether the first type of measurand and the second type of measurand under the measurement conditions have an association relationship is not taken into consideration.

[0250] For example, the first type of measurement object configured based on the configuration information includes M measurement objects, and the second type of measurement object configured based on the configuration information includes N measurement objects. For example, the first type of measurement object is an air interface measurement object, and the second type of measurement object is an SL measurement object. In this case, the M measurement objects are M air interface frequencies, and the N measurement objects are N SL frequencies. The measurement results of the M air interface frequencies may include measurement results of one or more cells at the M air interface frequencies. In these measurement results, if the value of one measurement result is equal to or greater than a first threshold, the remote UE can transmit the measurement result to the access network device, and does not need to transmit the measurement results of the second type of measurement object. Alternatively, if the values ​​of all measurement results corresponding to the M air interface frequencies (e.g., all measurement results of one or more cells) are less than the first threshold and the value of the measurement result of the relay UE in the measurement results of the N SL frequencies is greater than or equal to the second threshold (the measurement results of the N SL frequencies may include measurement results of one or more relay UEs operating at the N SL frequencies and on the sidelink), the remote UE may transmit the measurement results of the relay UE to the access network device and does not need to transmit the measurement results of the first type of measurement object. Alternatively, if the values ​​of all measurement results corresponding to the M air interface frequencies are less than the first threshold and the values ​​of all measurement results corresponding to the N SL frequencies are less than the second threshold, the remote UE may not transmit the measurement results to the access network device.

[0251] Alternatively, optionally, the first type of measurand and the second type of measurand under the measurement condition may have an association relationship. In other words, the measurement condition is, for example, as follows: the value of the measurement result of the first type of measurand is less than a first threshold, and the value of the measurement result of the second type of measurand having an association relationship with the first type of measurand is equal to or greater than a second threshold.

[0252] For example, the first type of measurement object configured based on the configuration information includes M measurement objects, and the second type of measurement object configured based on the configuration information includes N measurement objects. In this case, the remote UE can perform the determination for each of the M measurement objects separately. For example, the first type of measurement object is an air interface measurement object, and the second type of measurement object is an SL measurement object. In this case, the M measurement objects are M air interface frequencies, and the N measurement objects are N SL frequencies. For a first air interface frequency of the M air interface frequencies, the remote UE can measure one or more cells at the first air interface frequency to obtain one or more measurement results. In these measurement results, if a value of one measurement result is greater than a first threshold, the remote UE can transmit the measurement result to the access network device, and does not need to transmit the measurement result of the SL frequency corresponding to the first air interface frequency. If the values ​​of all the measurement results corresponding to the first air interface frequency are equal to or less than the first threshold, and the measurement results of the SL frequency corresponding to the first air interface frequency have values ​​greater than the second threshold, the remote UE can transmit the measurement results whose values ​​are greater than the second threshold to the access network device, and does not need to transmit the measurement results corresponding to the first air interface frequency. Alternatively, if the values ​​of all the measurement results corresponding to the first air interface frequency are equal to or less than the first threshold, and the values ​​of all the measurement results corresponding to the SL frequency corresponding to the first air interface frequency are equal to or less than the second threshold, the remote UE may not need to transmit the measurement results to the access network device. For another air interface frequency in the M air interface frequencies, the remote UE can use a similar processing scheme.

[0253] In another example, the first type of measurement object is a SL measurement object, and the second type of measurement object is an air interface measurement object. In this case, the M measurement objects are M SL frequencies, and the N measurement objects are N air interface frequencies. For a first air interface frequency in the N air interface frequencies, the remote UE can measure the SL frequencies that have an association relationship with the first air interface frequency, i.e., can measure relay UEs that operate on these SL frequencies and are on the sidelink, to obtain one or more measurement results. In these measurement results, if the value of one measurement result is greater than a first threshold, the remote UE can transmit the measurement result to the access network device, and does not need to transmit the measurement result of the first air interface frequency. In the case where the values ​​of all the measurement results corresponding to these SL frequencies are less than or equal to the first threshold, and in the measurement result of the first air interface frequency, the value of the measurement result is greater than a second threshold, the remote UE can transmit the measurement result of the SL frequency corresponding to the first air interface frequency, whose value is greater than the second threshold, to the access network device, and does not need to transmit the measurement result of the SL frequency corresponding to the first air interface frequency. Alternatively, if the values ​​of all the measurement results corresponding to these SL frequencies are less than or equal to the first threshold and the values ​​of all the measurement results corresponding to the first air interface frequency are less than or equal to the second threshold, the remote UE may not transmit the measurement results to the access network device. For another air interface frequency in the N air interface frequencies, the remote UE may use a similar processing scheme.

[0254] In another example, the measurement event configured for the SL measurement object is as follows: the value of the measurement result of the air interface neighbor cell is less than a first threshold, and the value of the measurement result of the neighbor relay UE is greater than or equal to a second threshold. The measurement results of the M air interface frequencies may include measurement results of one or more cells under the M air interface frequencies. In these measurement results, if the value of one measurement result is greater than or equal to the first threshold (i.e., the measurement result of a particular neighbor cell in the M air interface frequencies is good), the measurement report of the SL measurement object is not triggered, and the remote UE does not need to transmit the measurement result of the SL measurement object. However, if all values ​​of the measurement results of the M air interface frequencies (e.g., all measurement results of one or more cells) are less than the first threshold, and the value of the measurement result of the neighbor relay UE measured on the SL measurement object is greater than a second threshold, the remote UE is triggered to transmit the measurement result of the SL measurement object to the access network device. That is, the remote UE can transmit the measurement result of the neighbor relay UE to the access network device.

[0255] Alternatively, the measurement event configured for the SL measurement object is as follows: the measurement result of a neighboring cell on a measurement object (i.e., a specific frequency) of a specific air interface MO is less than a first threshold, and the measurement result of a neighboring relay UE is equal to or greater than a second threshold. Alternatively, if the values ​​of all measurement results (e.g., all measurement results of one or more cells) corresponding to the air interface frequency are less than a first threshold, and the measurement result of a relay UE is equal to or greater than a second threshold in the measurement results of the SL frequency (the measurement results of the SL frequency may include the measurement results of one or more relay UEs operating on the SL frequency and on the sidelink), a measurement report of the remote UE is triggered, and the remote UE can transmit the measurement result of the relay UE to the access network device. If the measurement event is configured and the access network device determines that the air interface quality is good, the access network device may not configure a relay path to avoid the reporting of unnecessary measurement results by the remote UE as much as possible, thereby reducing the power consumption of the remote UE.

[0256] In another example, the measurement event configured for the air interface measurement object is as follows: the value of the measurement result of the SL measurement object is less than a first threshold, and the value of the measurement result of the neighboring cell on the air interface measurement object is greater than or equal to a second threshold. The measurement results of the N SL frequencies may include measurement results of one or more cells at the N SL frequencies. In these measurement results, if the value of one measurement result is greater than or equal to the first threshold (i.e., the measurement result of a particular neighboring relay UE at the N SL frequencies is good), no air interface measurement report is triggered and the remote UE does not need to transmit the measurement result of the air interface measurement object. However, if all values ​​of the measurement results of the N SL frequencies (e.g., all measurement results of one or more relay UEs) are less than the first threshold and the result of the neighboring cell measured on the air interface measurement object is greater than or equal to the second threshold, the remote UE is triggered to transmit the measurement result in the measurement result of the air interface measurement object to the access network device.

[0257] Alternatively, the measurement event configured for the air interface measurement object is as follows: the measurement result of the neighbor relay UE on the measurement object (i.e., the specific SL frequency) at a specific SL frequency is less than a first threshold, and the measurement result of the air interface neighbor cell is equal to or greater than a second threshold. If the values ​​of all the measurement results (e.g., all the measurement results of one or more relay UEs) corresponding to the SL frequency are less than the first threshold, and the value of the measurement result of the neighbor cell is equal to or greater than a second threshold in the measurement results of the air interface frequency (the measurement results of the air interface frequency may include the measurement results of one or more cells operating at the air interface frequency), a measurement report is triggered, and the remote UE can transmit to the access network device a measurement result of the air interface frequency, the value of which is equal to or greater than the second threshold in the measurement results. If the measurement event is configured and the access network device determines that the relay path is good, the access network device may not configure a relay path to avoid the reporting of useless measurement results by the remote UE as much as possible, thereby reducing the power consumption of the remote UE.

[0258] 2. Multiple types of measurement events are configured based on the configuration information, for example, a first measurement event, a second measurement event, and a third measurement event are configured.

[0259] The remote UE may perform a decision on the obtained measurement results to decide whether to send the measurement results to the access network device or to decide a particular measurement result to be sent to the access network device. For example, if a value of the measurement result of a first type of measurement object is less than a first threshold, the remote UE may send the measurement result to the access network device. If a value of the measurement result of a second type of measurement object is equal to or greater than a second threshold, the remote UE may send the measurement result to the access network device. If a value of the measurement result of the first type of measurement object is equal to or greater than the first threshold, the remote UE may send the measurement result to the access network device.

[0260] Optionally, in this configuration manner, the remote UE does not need to consider the association relationship between the first type of measurement object and the second type of measurement object, and only needs to select a measurement result based on the corresponding measurement event. For example, the first type of measurement object configured based on the configuration information includes M measurement objects, and the M measurement objects are, for example, M measurement frequencies. An example is used in which the M measurement frequencies are M air interface frequencies. For a first air interface frequency among the M air interface frequencies, the remote UE measures one or more cells at the first air interface frequency to obtain one or more measurement results. In these measurement results, if the value of the measurement result is equal to or greater than a first threshold, the remote UE can transmit the measurement result whose value is equal to or greater than the first threshold to the access network device. In these measurement results, if the value of the measurement result is less than the first threshold, the remote UE can also transmit the measurement result whose value is less than the first threshold to the access network device. For another air interface frequency in the M air interface frequencies, the remote UE uses the same processing manner.

[0261] Alternatively, an example is used in which the M measurement frequencies are M SL frequencies. For a first SL frequency in the M SL frequencies, the remote UE operates at the first SL frequency and measures one or more relay UEs on the sidelink to obtain one or more measurement results. For these measurement results, if the value of the measurement result is equal to or greater than a first threshold, the remote UE can transmit the measurement result whose value is equal to or greater than the first threshold to the access network device. For these measurement results, if the value of the measurement result is less than the first threshold, the remote UE can also transmit the measurement result whose value is less than the first threshold to the access network device. For another air interface frequency in the M air interface frequencies, the remote UE uses the same processing scheme.

[0262] For example, the second type of measurement objects configured based on the configuration information includes N measurement objects, and the N measurement objects are, for example, N measurement frequencies. An example is used in which the N measurement frequencies are N air interface frequencies. For a second air interface frequency among the N air interface frequencies, the remote UE measures one or more cells at the second air interface frequency to obtain one or more measurement results. In these measurement results, if the value of the measurement result is equal to or greater than a second threshold, the remote UE can transmit the measurement result whose value is equal to or greater than the second threshold to the access network device. In these measurement results, the measurement result whose value is less than the second threshold may not be transmitted by the remote UE to the access network device. For another air interface frequency in the M air interface frequencies, the remote UE uses the same processing scheme.

[0263] Alternatively, an example is used in which the N measurement frequencies are N SL frequencies. For a second SL frequency in the N SL frequencies, the remote UE operates at the second SL frequency and measures one or more relay UEs on the sidelink to obtain one or more measurement results. For these measurement results, if the value of the measurement result is equal to or greater than the second threshold, the remote UE can transmit the measurement result whose value is equal to or greater than the second threshold to the access network device. For these measurement results, the measurement result whose value is less than the second threshold may not be transmitted by the remote UE to the access network device. For another SL frequency in the M SL frequencies, the remote UE uses the same processing scheme.

[0264] In another example, the access network device first configures an air interface measurement object for the remote UE, and the configured measurement events for the air interface measurement object are as follows: the value of the measurement result of the air interface neighboring cell is less than a first threshold. The measurement results of the M air interface frequencies may include measurement results of one or more cells at the M air interface frequencies. In these measurement results, if the value of one measurement result is equal to or greater than the first threshold (i.e., the measurement result of a specific neighboring cell at the M air interface frequencies is good), the air interface measurement report is not triggered and the remote UE does not need to transmit the measurement results of the M air interface frequencies. However, if the remote UE cannot measure the air interface frequency or if all values ​​of the measurement results of the M air interface frequencies measured by the remote UE are less than the first threshold, the measurement report of the air interface measurement object is triggered and the remote UE transmits the measurement result of the air interface measurement object to the access network device. The aforementioned measurement events are configured to enable the access network device to timely obtain the case of a bad air interface and timely configure a new measurement event for the remote UE. In this way, the remote UE can measure the SL in a timely manner, thereby shortening the time to add a new communication path for the remote UE. Optionally, the access network device can configure an SL measurement object and a measurement event for the remote UE when it determines that the air interface is poor. For example, the measurement event is as follows: the value of the measurement result of the neighboring relay UE measured on the SL measurement object is equal to or greater than a second threshold. The remote UE can measure the SL measurement object.If the value of the relay UE's measurement result (e.g., the remote UE measuring the SL measurement object may include measuring one or more relay UEs that operate on the frequency corresponding to the SL measurement object and are on the sidelink, and the measurement result in this specification may include some or all of the measurement results) is equal to or greater than the second threshold, a measurement report is triggered, and the remote UE can transmit the SL measurement result whose value is equal to or greater than the second threshold to the access network device. Alternatively, if all measurement results obtained by the remote UE by measuring the SL measurement object are less than the second threshold or the remote UE does not obtain a measurement result, the measurement report is not triggered. A measurement event on the SL is triggered and reported, so that the access network device can further configure a relay path for the remote UE based on the measurement result.

[0265] In another example, the access network device first configures an SL measurement object for the remote UE, and the configured measurement event for the SL measurement object is as follows: the value of the measurement result of the relay UE measured on the SL measurement object is less than a first threshold. The measurement result of each SL frequency may include one or more relay UE measurement results. In these measurement results, if the value of one measurement result is equal to or greater than the first threshold (i.e., the measurement result of a particular relay UE on the SL is good), the measurement report of the SL measurement object is not triggered, and the remote UE does not need to send the measurement result of the SL measurement object. However, if the remote UE fails to measure the SL measurement object, or if the value of the measurement result of the SL measurement object measured by the remote UE is less than the first threshold (e.g., all values ​​of the measurement results of all relay UEs corresponding to the SL measurement object are less than the first threshold), the measurement report of the SL measurement object is triggered, and the remote UE sends the result of the SL measurement object to the access network device. The aforementioned measurement event is configured so that the access network device can obtain the case of poor SL quality in time and configure a new measurement event for the remote UE in time. In this way, the remote UE can measure the air interface in time, thereby shortening the time to add a new communication path for the remote UE. Optionally, the access network device can configure an air interface measurement object and a measurement event for the remote UE when it determines that the SL is poor. For example, the measurement event is as follows: the value of the measurement result of the neighboring cell measured on the air interface measurement object is equal to or greater than a second threshold. The remote UE may measure the air interface measurement object.If a value of a measurement result of a measured cell (e.g., the remote UE measuring an air interface measurement object may include measuring one or more cells at an air interface frequency corresponding to the air interface measurement object, and the measurement result in this specification may include some or all of the measurement result) is equal to or greater than the second threshold, a measurement report is triggered, and the remote UE can transmit to the access network device the air interface measurement result whose value is equal to or greater than the second threshold. Alternatively, if all values ​​of the measurement results obtained by the remote UE by measuring the air interface measurement object are less than the second threshold or the remote UE does not obtain a measurement result, the measurement report is not triggered. A measurement event on the air interface is triggered and reported, so that the access network device can further configure, for the remote UE, a direct connection path to the network based on the measurement result.

[0266] S504: The access network device determines a communication path of the remote UE based on the measurement result. A second access network device may be involved in S504. Therefore, the access network device that performs S501 to S504 may alternatively be referred to as a first access network device.

[0267] For more details about S504, please refer to S304 in the embodiment shown in FIG. 3A.

[0268] S505: The first access network device sends an RRC reconfiguration message to the remote UE. In response, the remote UE receives an RRC reconfiguration message from the first access network device.

[0269] For more details about S505, please refer to S305 in the embodiment shown in FIG. 3B.

[0270] S506: The remote UE establishes a connection to the first relay UE, where the connection is, for example, a unicast connection.

[0271] For more details about S506, please refer to S306 in the embodiment shown in FIG. 3B.

[0272] S507: The second access network device sends an RRC reconfiguration message to the first relay UE. In response, the first relay UE receives an RRC reconfiguration message from the second access network device. For distinction, the RRC reconfiguration message of S505 may alternatively be referred to as a first RRC reconfiguration message, and the RRC reconfiguration message of S507 may alternatively be referred to as a second RRC reconfiguration message.

[0273] The second RRC reconfiguration message may be used to configure the first relay UE, so that the remote UE may connect to the network using the first relay UE.

[0274] S508: The first relay UE sends a second RRC reconfiguration complete message to the second access network device. In response, the second access network device receives a second RRC reconfiguration complete message from the first relay UE. After completing the configuration based on the second RRC reconfiguration message, the first relay UE can execute S508. S507 and S508 indicate the information exchange between the first relay UE and the access network device after the first relay UE enters the RRC connected state.

[0275] S509: The remote UE sends a first RRC reconfiguration complete message. For example, the remote UE sends a first RRC reconfiguration message to the first relay UE, and the first relay UE receives the first RRC reconfiguration complete message from the remote UE. Then, the first relay UE sends the first RRC reconfiguration complete message to the second access network device, and the second access network device receives the first RRC reconfiguration message from the first relay UE.

[0276] In another example, if the route of the first relay UE is a route added by the first access network device for the remote UE, after a connection between the first relay UE and the second access network device is successfully established (e.g., the first relay UE successfully randomly accesses the second access network device, or timer T300 or timer T301 stops, or the first relay UE enters an RRC connected state), and after the remote UE receives an indication from the first relay UE, the remote UE may send a first RRC reconfiguration complete message to the first access network device.

[0277] Similarly, the first access network device and the second access network device may be different access network devices or may be the same access network device. If the first access network device and the second access network device are the same access network device, please refer to S307-S309 in the embodiment shown in Figure 3B for the implementation form of S507-S509.

[0278] Any of S504 to S509 is an optional step.

[0279] In this embodiment of the present application, the access network device can select a preferred reported measurement result based on a configured measurement event, and the remote UE can send the measurement result to the access network device based on the measurement event, so that the sent measurement result better meets the requirements of the access network device, thereby reducing redundant reporting of the remote UE and reducing transmission overhead.

[0280] Currently, before a remote UE is added to a relay path or before a remote UE switches to a relay path, the relay UE searched by the remote UE may be in an RRC idle state or an RRC inactive state. When a relay UE selected by a remote UE or selected by an access network device is in an RRC idle state or an RRC inactive state, the relay UE needs to enter an RRC connected state. Currently, a reasonable scheme is as follows: the remote UE uses the relay UE to send an RRC configuration complete message to the access network device, and the relay UE triggers the relay UE to enter an RRC connected state by receiving the RRC configuration complete message. However, the RRC layer of the relay UE does not analyze the message from the remote UE. Therefore, it can be found that in the current solution, the relay UE cannot know which specific message is the RRC configuration complete message and may not enter the RRC connected state. Similarly, a remote UE in an RRC idle state or an RRC inactive state expects a relay UE in an RRC idle state or an RRC inactive state to send a connection establishment request message or a connection resume message to the relay UE when the relay UE in an RRC idle state or an RRC inactive state executes a service or when the relay UE in an RRC idle state or an RRC inactive state initiates a connection re-establishment, so that the relay UE may be triggered to enter an RRC connected state. However, the RRC layer of the relay UE does not analyze the message from the remote UE. Therefore, in the current solution, the relay UE still cannot know which specific message is the connection establishment request message or the connection resume message, and still cannot enter the RRC connected state.

[0281] In view of this, the embodiment of the present application provides a sixth communication method. In this method, the relay UE can determine whether the relay UE needs to enter an RRC connected state based on whether the first data packet is received by a logical channel or by an RLC entity that receives a message on a sidelink. This provides an implementation mechanism for the relay UE to enter an RRC connected state. Figure 6 is a flowchart of this method.

[0282] S601a: The remote UE sends an RRC reconfiguration complete message to the relay UE, and in response, the relay UE receives an RRC reconfiguration complete message from the remote UE.

[0283] Since the first relay UE knows the PC5 RLC configuration used to send the RRC reconfiguration complete message (e.g., the PC5 RLC configuration is the default PC5 RLC configuration or is configured by the remote UE via PC5 RRC), the first relay UE can determine whether the first relay UE needs to be triggered to enter the RRC connected state based on whether there is a specific PC5 LCID or whether a data packet is received on the SL RLC bearer, or in other words, based on whether a data packet is received on the LCID or SL RLC bearer to send the RRC reconfiguration complete message. For example, when the first relay UE is in the RRC idle state, if the first relay UE receives any message sent via SL-RLC 1 (sidelink RLC 1, the RLC channel used to send the remote UE's SRB 1 on the sidelink) from the L2 U2N remote UE, the RRC layer of the first relay UE can initiate the RRC connection establishment process to enter the RRC connected state. As another example, when the first relay UE is in an RRC inactive state, if the first relay UE receives any message sent via SL-RLC 1 (sidelink RLC 1, an RLC channel used to transmit the remote UE's SRB 1 on the sidelink) from the L2 U2N remote UE, the RRC layer of the first relay UE may initiate an RRC connection resumption process to enter an RRC connected state.

[0284] However, since the first relay UE receives the message over SL-RLC and does not send the message to the RRC layer of the first relay UE for parsing, the RRC layer of the first relay UE requires the lowest layer to inform the RRC layer of the first relay UE whether the SL-RLC receives a data packet.

[0285] In one possible scheme, when the RRC layer of the first relay UE determines that the first relay UE is in an RRC idle state or an RRC inactive state and receives an indication that the MAC layer or the RLC layer receives a data packet on a specific LCID, the RRC layer can determine that the condition for the first relay UE to enter an RRC connected state is met. In this case, the RRC layer of the first relay UE can notify the NAS of the first relay UE that the first relay UE needs to enter an RRC connected state. The NAS can deliver an indication to the RRC layer to trigger the RRC layer to initiate an RRC connection establishment process or an RRC connection resumption process to enter the RRC connected state.

[0286] For example, when the MAC layer receives a MAC SDU on a logical channel with source L2 ID equal to X and LCID equal to 1 (the LCID of the logical channel carrying an RRC reconfiguration complete message), if the MAC SDU is the first MAC SDU received on the logical channel with source L2 ID equal to X and LCID equal to 1, the MAC layer determines whether data was previously received on a logical channel with source L2 ID equal to X and LCID equal to 0 (the LCID of the logical channel carrying an RRC connection establishment request message or an RRC connection resume request message). If no data is received, the MAC layer can send an indication to the RRC layer to indicate that a data packet is received on the particular LCID.

[0287] In another example, when an RLC bearer (e.g., SL-RLC 1) corresponding to an LCID equal to 1 (the LCID of the logical channel carrying the RRC reconfiguration complete message) receives an RLC PDU, if the RLC PDU is the first RLC PDU received on the RLC bearer, the RLC layer may send an indication to the RRC layer to indicate that a data packet was received on the particular LCID.

[0288] In another possible manner, when the RRC layer of the first relay UE determines that the relay UE is in an RRC inactive state and receives an indication that the MAC layer or the RLC layer receives a data packet on a specific LCID, the RRC layer determines that the condition for the first relay UE to enter an RRC connected state is met. In this case, the RRC layer can initiate an RRC connection resumption process to trigger entering the RRC connected state.

[0289] For example, when the MAC layer receives a MAC SDU on a logical channel with source L2 ID equal to X and LCID equal to 1 (the LCID of the logical channel carrying an RRC reconfiguration complete message), if the MAC SDU is the first MAC SDU received on the logical channel with source L2 ID equal to X and LCID equal to 1, the MAC layer determines whether data was previously received on a logical channel with source L2 ID equal to X and LCID equal to 0 (the LCID of the logical channel carrying an RRC connection establishment request message or an RRC connection resume request message). If no data is received, the MAC layer can send an indication to the RRC layer to indicate that a data packet is received on the particular LCID.

[0290] In another example, when an RLC bearer (e.g., SL-RLC 1) corresponding to an LCID equal to 1 (the LCID of the logical channel carrying the RRC reconfiguration complete message) receives an RLC PDU, if the RLC PDU is the first RLC PDU received on the RLC bearer, the RLC layer may send an indication to the RRC layer to indicate that a data packet was received on the particular LCID.

[0291] S601b: the remote UE sends an RRC connection establishment request message to the relay UE, and the relay UE correspondingly receives an RRC connection establishment request message from the remote UE. Alternatively, the remote UE sends an RRC connection resumption message to the relay UE, and the relay UE correspondingly receives an RRC connection resumption message from the remote UE. Alternatively, the remote UE sends an RRC connection re-establishment request message to the relay UE, and the relay UE correspondingly receives an RRC connection re-establishment request message from the remote UE.

[0292] Since the first relay UE knows the PC5 RLC configuration (e.g., the PC5 RLC configuration is the default PC5 RLC configuration) used to transmit the RRC connection establishment request message, the RRC connection resume message, or the RRC connection re-establishment request message, the first relay UE can determine whether the first relay UE needs to be triggered to enter the RRC connected state based on whether there is a specific PC5 LCID or whether a data packet is received on the SL RLC bearer, or in other words, based on whether a data packet configured to transmit the RRC reconfiguration complete message is received on the LCID or the SL RLC bearer. For example, when the first relay UE is in the RRC idle state, if the first relay UE receives any message transmitted via SL-RLC 0 (sidelink RLC 0, the RLC channel used to transmit the remote UE's SRB 0 on the sidelink) from the L2 U2N remote UE, the RRC layer of the first relay UE can initiate the RRC connection establishment process to enter the RRC connected state. As another example, when the first relay UE is in an RRC inactive state, if the first relay UE receives any message sent via SL-RLC 0 (sidelink RLC 0, an RLC channel used to transmit the remote UE's SRB 0 on the sidelink) from the L2 U2N remote UE, the RRC layer of the first relay UE may initiate an RRC connection resumption process to enter an RRC connected state.

[0293] However, since the first relay UE receives the message over SL-RLC and does not send the message to the RRC layer of the first relay UE for parsing, the RRC layer of the first relay UE requires the lowest layer to inform the RRC layer of the first relay UE whether the SL-RLC receives a data packet.

[0294] In one possible scheme, when the RRC layer of the first relay UE determines that the first relay UE is in an RRC idle state or an RRC inactive state and receives an indication that the MAC layer or the RLC layer receives a data packet on a specific LCID, the RRC layer can determine that the conditions for the first relay UE to enter the RRC connected state are met. In this case, the RRC layer can notify the NAS of the first relay UE that the first relay UE needs to enter the RRC connected state. The NAS delivers an indication to the RRC layer to trigger the RRC layer to initiate an RRC connection establishment process or an RRC connection resumption process to enter the RRC connected state.

[0295] For example, when the MAC layer receives a MAC SDU on a logical channel with source L2 ID equal to X and LCID equal to 0 (the LCID of the logical channel carrying an RRC Connection Establishment Request message, an RRC Connection Resume message, or an RRC Connection Re-establishment Request message), if the MAC SDU is the first MAC SDU received on the logical channel with source L2 ID equal to X and LCID equal to 0, the MAC layer may send an indication to the RRC layer to indicate that a data packet was received on the particular LCID.

[0296] In another example, when an RLC bearer (e.g., SL-RLC 0) corresponding to an LCID equal to 0 (the LCID of a logical channel carrying an RRC Connection Establishment Request message, an RRC Connection Resume message, or an RRC Connection Re-establishment Request message) receives an RLC PDU, if the RLC PDU is the first RLC PDU received on the RLC bearer, the RLC layer may send an indication to the RRC layer to indicate that a data packet was received on the particular LCID.

[0297] In another possible manner, when the RRC layer of the first relay UE determines that the relay UE is in an RRC inactive state and receives an indication that the MAC layer or the RLC layer receives a data packet on a specific LCID, the RRC layer can determine that the condition for the first relay UE to enter an RRC connected state is met. In this case, the RRC layer can initiate an RRC connection resumption process to trigger entering the RRC connected state.

[0298] For example, when the MAC layer receives a MAC SDU on a logical channel with source L2 ID equal to X and LCID (the LCID of the logical channel carrying the RRC connection establishment request message, the RRC connection resume message, or the RRC connection re-establishment request message) equal to 0, the MAC layer may send an indication to the RRC layer to indicate that a data packet was received on the particular LCID.

[0299] In another example, when an RLC bearer (e.g., SL-RLC 0) corresponding to an LCID equal to 0 (the LCID of a logical channel carrying an RRC Connection Establishment Request message, an RRC Connection Resume message, or an RRC Connection Re-establishment Request message) receives an RLC PDU, if the RLC PDU is the first RLC PDU received on the RLC bearer, the RLC layer may send an indication to the RRC layer to indicate that a data packet was received on the particular LCID.

[0300] S601a and S601b are two optional implementations, and the two can be considered to be in an "and / or" relationship.

[0301] S602: The relay UE sends an RRC connection establishment request message to the access network device, and the access network device correspondingly receives the RRC connection establishment request message sent by the relay UE. Alternatively, the first relay UE sends an RRC connection resumption message to the access network device, and the access network device correspondingly receives the RRC connection resumption message sent by the relay UE.

[0302] The first relay UE may enter an RRC connected state by executing S602 to provide corresponding services to the remote UE.

[0303] Any two or more of the embodiments shown in FIG. 2 to FIG. 6 provided in this application can be combined for application. For example, the remote UE performs a measurement process according to the embodiment shown in FIG. 3A and FIG. 3B, and determines the measurement results to be reported according to the embodiment shown in FIG. 5. Alternatively, the remote UE performs a measurement process according to the embodiment shown in FIG. 4A and FIG. 4B, and determines the measurement results to be reported according to the embodiment shown in FIG. 5. Alternatively, the remote UE performs a measurement process according to the embodiment shown in FIG. 3A and FIG. 3B, performs a measurement according to the embodiment shown in FIG. 4A and FIG. 4B, and determines the measurement results to be reported according to the embodiment shown in FIG. 5, or performs a measurement according to the embodiment shown in FIG. 2 to FIG. 5, and enables the relay UE to enter the RRC connected state, etc. according to the solution of FIG. 6. Alternatively, the embodiments shown in FIG. 2 to FIG. 6 may not be combined, and are applied separately and individually.

[0304] FIG. 7 is a schematic diagram of the structure of a communication device according to an embodiment of the present application. The communication device 700 may be a remote UE or a circuit system of a remote UE according to any one of the embodiments shown in FIG. 2 to the embodiments shown in FIG. 6, and is configured to implement a method corresponding to the remote UE in the aforementioned method embodiment. Alternatively, the communication device 700 may be a relay UE (e.g., a first relay UE) or a circuit system of a relay UE according to any one of the embodiments shown in FIG. 2 to the embodiments shown in FIG. 6, and is configured to implement a method corresponding to the relay UE in the aforementioned method embodiment. Alternatively, the communication device 700 may be an access network device or a circuit system of an access network device according to any one of the embodiments shown in FIG. 2 to the embodiments shown in FIG. 6, and is configured to implement a method corresponding to the access network device in the aforementioned method embodiment. Alternatively, the communication device 700 may be a first access network device or a circuit system of a first access network device according to any one of the embodiments shown in FIG. 2 to the embodiments shown in FIG. 5, and is configured to implement a method corresponding to the first access network device in the aforementioned method embodiment. Alternatively, the communication device 700 may be a second access network device or a circuit system of the second access network device according to any one of the embodiments shown in Fig. 2 to Fig. 5, and is configured to implement a method corresponding to the second access network device of the above-mentioned method embodiments. For specific functions, please refer to the description of the above-mentioned method embodiments. For example, the circuit system is a chip system.

[0305] The communication device 700 includes at least one processor 701. The processor 701 may be configured for internal processing of the device to implement certain control processing functions. Optionally, the processor 701 includes instructions. Optionally, the processor 701 may store data. Optionally, separate processors may be separate components, may be located in separate physical locations, or may be located in separate integrated circuits. Optionally, separate processors may be integrated into one or more processors, e.g., integrated into one or more integrated circuits.

[0306] Optionally, the communications device 700 includes one or more memories 703 configured to store instructions. Optionally, the memory 703 may further store data. The processor and memory may be located separately or integrated together.

[0307] Optionally, communication device 700 includes communication line 702 and at least one communication interface 704. Memory 703, communication line 702, and communication interface 704 are all optional, and therefore in FIG. 7 memory 703, communication line 702, and communication interface 704 are all represented by dashed lines.

[0308] Optionally, the communication device 700 may further include a transceiver and / or an antenna. The transceiver may be configured to transmit information to another device or receive information from another device. The transceiver may also be referred to as a transceiver machine, a transceiver circuit, an input / output interface, etc., and is configured to implement a transceiver function of the communication device 700 using an antenna. Optionally, the transceiver includes a transmitter and a receiver. For example, the transmitter may be configured to generate a radio frequency signal based on a baseband signal, and the receiver may be configured to convert the radio frequency signal to a baseband signal.

[0309] The processor 701 may include a general purpose central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), or one or more integrated circuits configured to control program execution of the solutions of the present application.

[0310] Communications lines 702 may include paths for transmitting information between the aforementioned components.

[0311] The communication interface 704 is configured to communicate with another device or a communication network, such as Ethernet, a radio access network (RAN), a wireless local area network (WLAN), or a wired access network, using any device, such as a transceiver.

[0312] The memory 703 may be, but is not limited to, a read-only memory (ROM) or another type of static storage device capable of storing static information and instructions, a random access memory (RAM) or another type of dynamic storage device capable of storing information and instructions, an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or another type of optical disk storage, an optical disk storage (including compact optical disks, laser disks, optical disks, digital versatile optical disks, Blu-ray disks, etc.), a magnetic disk storage medium or another type of magnetic storage device, or any other medium that can be configured to carry or store predetermined program code in the form of instructions or data structures and that can be accessed by a computer. The memory 703 may exist independently and is connected to the processor 701 through communication lines 702. Alternatively, the memory 703 may be integrated with the processor 701.

[0313] The memory 703 is configured to store computer-executable instructions for carrying out the solutions of the present application, and the processor 701 controls the execution. The processor 701 is configured to execute the computer-executable instructions stored in the memory 703 to implement the communication methods provided in the aforementioned embodiments of the present application.

[0314] Optionally, the computer-executable instructions in this embodiment of the present application may be referred to as application program code, although this is not specifically limited in this embodiment of the present application.

[0315] In a specific implementation, in one embodiment, the processor 701 may include one or more CPUs, for example, CPU0 and CPU1 of FIG.

[0316] In a specific implementation, in one embodiment, the communications device 700 may include multiple processors, such as processor 701 and processor 708 of FIG. 7. Each of the processors may be a single-core (single-CPU) processor or a multi-core (multi-CPU) processor. A processor herein may be one or more devices, circuits, and / or processing cores configured to process data (e.g., computer program instructions).

[0317] 7 is a chip, for example, a chip of an access network device, a chip of a UPF, a chip of an SMF, or a chip of a terminal device, the chip includes a processor 701 (and may further include a processor 708), a communication line 702, a memory 703, and a communication interface 704. Specifically, the communication interface 704 may be an input interface, a pin, a circuit, etc. The memory 703 may be a register, a cache, etc. The processor 701 and the processor 708 may each be a general-purpose CPU, a microprocessor, an ASIC, or one or more integrated circuits for controlling the execution of a program of the communication method in any one of the foregoing embodiments.

[0318] In a first implementation form, the communication device 700 may be configured to implement the method corresponding to the UE of the above-mentioned embodiment of the present application. For specific functions, please refer to the description of the above-mentioned embodiment.

[0319] For example, the communication device 700 includes a processor 701. The processor 701 is configured to execute a computer program or instructions so that a method corresponding to the UE in the aforementioned embodiment of the present application is executed. For example, the method corresponding to the remote UE (or referred to as UE) in the aforementioned embodiment of the present application includes the steps of: acquiring frequency information of a first cell, where the first cell is a cell in which a first relay device is located; determining the first cell based on the frequency information of the first cell and an identifier of the first cell; and measuring the first cell to determine whether the terminal device can act as a remote device in the first cell.

[0320] In another example, a method corresponding to the first relay UE in the aforementioned embodiment of the present application includes a step of transmitting frequency information of a first cell to a terminal device, where the frequency information of the first cell is used to determine whether the terminal device can function as a remote device in the first cell, and the first cell is a cell in which the first relay device is located.

[0321] In the embodiment of the present application, the device may be divided into functional modules based on the above-mentioned method example. For example, each functional module may be obtained by division based on each corresponding function, or two or more functions may be integrated into one processing module. The integrated module may be implemented in the form of hardware or in the form of a software functional module. It should be noted that in the embodiment of the present application, the division of modules is an example and is merely a division of logical functions. Another division method may be used during actual implementation. For example, when each functional module is obtained by division based on each corresponding function, FIG. 8 is a schematic diagram of the device. The device 800 may be an access network device or a terminal device in the above-mentioned method embodiment, or may be a chip in the access network device or a chip in the terminal device. The device 800 includes a transmitting unit 801, a processing unit 802, and a receiving unit 803.

[0322] It should be understood that the device 800 may be configured to implement the steps performed by an access network device or a terminal device in the method in the embodiment of the present application. For related features, please refer to the above-mentioned embodiment. Details are not repeated in this specification.

[0323] Optionally, the functions / implementation processes of the transmitting unit 801, the receiving unit 803, and the processing unit 802 in Figure 8 may be implemented by the processor 701 and / or the processor 708 in Figure 7 by invoking computer-executable instructions stored in the memory 703. Alternatively, the functions / implementation processes of the processing unit 802 in Figure 8 may be implemented by the processor 701 and / or the processor 708 in Figure 7 by invoking computer-executable instructions stored in the memory 703, and the functions / implementation processes of the transmitting unit 801 and the receiving unit 803 in Figure 8 may be implemented using the communication interface 704 in Figure 7.

[0324] Optionally, if the device 800 is a chip or a circuit, the functions / implementation processes of the sending unit 801 and the receiving unit 803 may be alternatively implemented using pins, circuits, etc.

[0325] The present application further provides a computer-readable storage medium. The computer-readable storage medium stores a computer program or instructions. When the computer program is run or the instructions are run, the method performed by the access network device or the terminal device in the above-mentioned method embodiment is implemented. In this way, the functions of the above-mentioned embodiment may be implemented in the form of a software functional unit and sold or used as an independent product. Based on such understanding, the technical solution of the present application may be essentially, or the part that contributes to the prior art, or part of the technical solution may be implemented in the form of a software product. The computer software product includes some instructions stored in a storage medium and instructing a computer device (which may be a personal computer, a server, a network device, etc.) to perform all or part of the steps of the method described in the embodiment of the present application. The storage medium includes any medium that can store a program code, such as a USB flash drive, a removable hard disk, a ROM, a RAM, a magnetic disk, or an optical disk.

[0326] The present application further provides a computer program product, the computer program product including a computer program code, which, when run on a computer, enables the computer to execute the method executed by a terminal device or an access network device in any one of the aforementioned method embodiments.

[0327] An embodiment of the present application further provides a processing device, including a processor and an interface, the processor being configured to execute the method performed by the terminal device or the access network device in any one of the embodiments of the method described above.

[0328] All or part of the above embodiments may be implemented using software, hardware, firmware, or any combination thereof. When software is used to implement the embodiments, all or part of the embodiments may be implemented in the format of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded into a computer and executed, all or part of the process or function according to the embodiments of the present application is generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or another programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center in a wired (e.g., coaxial cable, optical fiber, or digital subscriber line (DSL)) or wireless (e.g., infrared, radio frequency, microwave) manner. The computer-readable storage medium may be any available medium accessible by a computer, or may be a data storage device that integrates one or more available media, such as a server or a data center. The usable medium may be a magnetic medium (eg, a floppy disk, a hard disk, or a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state disk (SSD)).

[0329] The various exemplary logic units and circuits described in the embodiments of this application may implement or operate the described functions by using a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. The general purpose processor may be a microprocessor. Optionally, the general purpose processor may alternatively be any conventional processor, controller, microcontroller, or state machine. The processor may alternatively be implemented by a combination of computing devices, such as a digital signal processor and a microprocessor, multiple microprocessors, one or more microprocessors with a digital signal processor core, or any other similar configuration.

[0330] The steps of the method or algorithm described in the embodiments of the present application may be directly embodied in hardware, in a software unit executed by a processor, or a combination thereof. The software unit may be stored in a RAM, a flash memory, a ROM, an erasable programmable read-only memory (EPROM), an EEPROM, a register, a hard disk, a removable disk, a CD-ROM, or in any other format of storage medium in the field. For example, the storage medium may be connected to the processor such that the processor can read information from the storage medium and write information to the storage medium. Optionally, the storage medium may alternatively be integrated in the processor. The processor and the storage medium may be located in an ASIC, and the ASIC may be located in a terminal device. Optionally, the processor and the storage medium may alternatively be located in different components in the terminal device.

[0331] These computer program instructions may alternatively be loaded into a computer or another programmable data processing device such that a sequence of operations and steps are executed on the computer or another programmable device to generate a computer-implemented process. Thus, the instructions executed on the computer or another programmable device provide steps for implementing a particular function within one or more processes of the flowcharts and / or one or more blocks of the block diagrams.

[0332] Although the embodiments of the present application have been described with reference to certain features and embodiments thereof, it is clear that various modifications and combinations may be made to the embodiments of the present application without departing from the scope of the embodiments of the present application. Correspondingly, the embodiments of the present application and the accompanying drawings are merely exemplary descriptions of the present application as defined by the appended claims, and any or all of the modifications, variations, combinations, or equivalents covering the scope of the embodiments of the present application are deemed to be included. It is clear that a person skilled in the art can make various modifications and variations to the embodiments of the present application without departing from the scope of the embodiments of the present application. Thus, the embodiments of the present application are also intended to encompass these modifications and variations if they are within the scope of the claims of the embodiments of the present application and their equivalent technologies.

[0333] Embodiment 1: A communication method applied to a remote device, the method comprising: receiving configuration information from a first access network device, the configuration information being used to configure a measurement frequency on a sidelink and to configure cell information or air interface frequency information; measuring a first type of relay device based on the configuration information, where the first type of relay device is a relay device that operates at a measurement frequency and has camped on or can camp on a cell corresponding to the cell information, or the first type of relay device is a relay device that operates at the measurement frequency and has camped on or can camp on a cell at a frequency corresponding to the air interface frequency information; transmitting the measurement results to a first access network device, the measurement results being used to determine a communication path for a remote device; A communication method comprising:

[0334] Embodiment 2: The method comprises: receiving a fourth message from the first relay device, the fourth message including information about a first frequency, the first frequency being a frequency of a cell in which the first relay device is located or a frequency of a cell on which the first relay device can camp; 2. The method of embodiment 1, further comprising:

[0335] Embodiment 3: The method of embodiment 2, wherein the fourth message is a discovery message or a PC5 RRC message.

[0336]

[0023] Embodiment 4: The step of measuring a first type of relay device based on the configuration information includes: measuring or measuring and reporting the first relay device if the first frequency belongs to a frequency corresponding to the air interface frequency information configured based on the configuration information, or if a cell corresponding to the cell information configured based on the configuration information belongs to the first frequency; 4. The method of embodiment 2 or 3, comprising:

[0337] Embodiment 5: The method comprises: sending a fifth message to the first relay device, the fifth message being used to inquire about frequency information of a cell in which the first relay device is located, or to inquire about frequency information of a cell on which the first relay device can camp, or to inquire whether the first relay device has camped on or can camp on a cell at a second frequency, the second frequency being a frequency corresponding to the air interface frequency information configured based on the configuration information; receiving a sixth message from the first relay device, the sixth message including information about the second frequency or the sixth message indicating that the first relay device has camped on or can camp on a cell at the second frequency; 2. The method of embodiment 1, further comprising:

[0338] Embodiment 6: The method comprises: receiving an RRC reconfiguration message from a first access network device, the RRC reconfiguration message instructing the remote device to handover to a second cell, or instructing the remote device to handover to a first relay device, or instructing the remote device to add the second cell as a secondary cell, or instructing the remote device to add a path for communicating with the network using the first relay device, the first relay device being one of a first type of relay device; 6. The method of any one of embodiments 1 to 5, further comprising:

[0339] Embodiment 7: The method according to embodiment 6, wherein the RRC reconfiguration message further includes the PCI of the cell in which the first relay device is located.

[0340]

[0023] Embodiment 8: The method according to embodiment 6 or 7, wherein the RRC reconfiguration message further includes frequency information of the cell in which the first relay device is located.

[0341] Embodiment 9: The method comprises: receiving, from the first intermediate device, a PCI of a cell in which the first intermediate device is located, after establishing a connection with the first intermediate device; 7. The method of embodiment 6, further comprising:

[0342] Embodiment 10: The method comprises: sending first instruction information to the first relay device after establishing a connection to the first relay device, the first instruction information instructing the first relay device to reselect a cell corresponding to the cell information configured based on the configuration information, or instructing the first relay device to reselect a cell at a frequency corresponding to the air interface frequency information configured based on the configuration information; 10. The method of any one of embodiments 6 to 9, further comprising:

[0343]

[0023] Embodiment 11: The method according to any one of embodiments 1 to 10, wherein the step of receiving configuration information from the first access network device includes a step of receiving the configuration information from the first access network device using a second relay device.

[0344] Embodiment 12: A communication method applied to a first relay device, the method comprising: transmitting information about a third frequency to the remote device, the third frequency being a frequency of a cell in which the first relay device is located or a frequency of a cell on which the first relay device can camp, the information about the third frequency being used to determine a communication path of the remote device; A communication method comprising:

[0345] Embodiment 13: The method of embodiment 11, wherein the step of transmitting information regarding the third frequency to the remote device includes a step of transmitting a fourth message to the remote device, the fourth message including information regarding the third frequency.

[0346] Embodiment 14: The method of embodiment 13, wherein the fourth message is a discovery message or a PC5 RRC message.

[0347] Embodiment 15: The third frequency is a frequency of a cell on which the first relay device can camp, and the method includes: receiving a first indication from the remote device after establishing a connection to the remote device, and reselecting a cell on a third frequency based on the first indication; or receiving second indication information from the first access network device, and handing over to a cell at a third frequency based on the second indication information; 15. The method of embodiment 13 or 14, further comprising:

[0348] Embodiment 16: The method comprises: receiving a fifth message from the remote device, the fifth message being used to inquire about frequency information of a cell in which the first relay device is located, or used to inquire about frequency information of a cell on which the first relay device can camp, or used to inquire whether the first relay device has camped on or can camp on a cell at a third frequency; Including, the step of transmitting information regarding the third frequency to the remote device includes a step of transmitting a sixth message to the remote device, the sixth message including information regarding the third frequency or the sixth message indicating that the first relay device has camped on or can camp on a cell at the third frequency; 13. The method of embodiment 12.

[0349] Embodiment 17: The method of embodiment 16, wherein the third frequency is a frequency of a cell on which the first relay device can camp, and the method further includes reselecting a cell on the third frequency.

[0350] Embodiment 18: A method according to any one of embodiments 12 to 17, wherein the method further includes a step of transmitting to the remote device a PCI of the cell in which the first relay device is located after establishing a connection to the remote device.

[0351]

[0046] Embodiment 19: A communication method applied to a first access network device, the method comprising: sending configuration information to a remote device, the configuration information being used to configure a measurement frequency on a sidelink and configuring cell information or air interface frequency information of a cell that a relay device operating on the measurement frequency needs to camp on or operate on; receiving measurements of the intermediate device from the remote device; determining a communication path for the remote device based on the measurement results; A communication method comprising:

[0352] Embodiment 20: The method comprises: sending a handover request message to a second access network device, the handover request message being used to inquire whether the remote device is willing to access the network using a first relay device served by the second access network device, or whether the remote device is willing to access a second cell served by the second access network device, the first relay device being determined based on a measurement result; receiving a handover request response from the second access network device, the handover request response indicating whether the remote device is willing to access the network using the first relay device or whether the remote device is willing to access the second cell; 20. The method of embodiment 19, further comprising:

[0353]

[0081] Embodiment 21: The method of embodiment 20, wherein the handover request response further includes frequency information of a cell on which the first relay device is camped or can be camped.

[0354] Embodiment 22: The method comprises: sending an RRC reconfiguration message to the remote device, the RRC reconfiguration message instructing the remote device to handover to the second cell, or instructing the remote device to handover to the first relay device, or instructing the remote device to add the second cell as a secondary cell, or instructing the remote device to add a path for communicating with the network using the first relay device; 22. The method of embodiment 21, further comprising:

[0355]

[0081] Embodiment 23: The method of embodiment 22, wherein the RRC reconfiguration message further includes the PCI of the cell in which the first relay device is located.

[0356]

[0081] Embodiment 24: The method according to embodiment 22 or 23, wherein the RRC reconfiguration message further includes frequency information of the cell in which the first relay device is located.

[0357]

[0081] Embodiment 25: A communication method applied to a first access network device, the method comprising: sending a handover request message to a second access network device, where the handover request message is used to inquire whether the remote device is willing to access a network using a first relay device served by the second access network device, or the handover request message is used to inquire whether the remote device is willing to access a second cell served by the second access network device; receiving a handover request response from a second access network device, the handover request response indicating whether the remote device is willing to access the network using the first relay device or indicating whether the remote device is willing to access a second cell, the handover request response further including frequency information of a cell on which the first relay device is camped or can be camped; A communication method comprising:

[0358]

[0081] Embodiment 26: The method of embodiment 25, wherein the handover request response further includes the PCI of the cell in which the first relay device is located.

[0359] Embodiment 27: The method comprises: sending an RRC reconfiguration message to the remote device, the RRC reconfiguration message instructing the remote device to handover to a second cell, or instructing the remote device to handover to a first relay device, or instructing the remote device to add the second cell as a secondary cell, or instructing the remote device to add a path for communicating with the network using the first relay device, the RRC reconfiguration message further including a PCI of a cell in which the first relay device is located; 27. The method of embodiment 25 or 26, further comprising:

[0360] Embodiment 28: The method comprises: determining that a frequency corresponding to the frequency information of a cell on which the first relay device is camped or can be camped is an operating frequency on the air interface of the relay device that is expected to serve the remote device; 28. The method of any one of embodiments 25 to 27, further comprising:

[0361]

[0081] Embodiment 29: A communication method applied to a second access network device, the method comprising: receiving a handover request message from a first access network device, the handover request message being used to inquire whether the remote device is willing to access a network using a first relay device served by a second access network device, or the handover request message being used to inquire whether the remote device is willing to access a second cell served by the second access network device; sending a handover request response to the first access network device, the handover request response indicating whether the remote device is willing to access the network using the first relay device or indicating whether the remote device is willing to access a second cell, the handover request response further including frequency information of a cell on which the first relay device is camped or can be camped; A communication method comprising:

[0362]

[0081] Embodiment 30: The method of embodiment 29, wherein the handover request response further includes the PCI of the cell in which the first relay device is located.

[0363]

[0081] Embodiment 31: A communication method for application to a remote device, comprising: receiving configuration information from the access network device, the configuration information being used to configure a first type of measurement object and a second type of measurement object, wherein a communication path of the remote device corresponding to the first type of measurement object is different from a communication path of the remote device corresponding to the first type of measurement object; Measuring a first type of measurement object based on the configuration information; measuring a second type of measurement object when the measurement result of the first type of measurement object does not satisfy the first condition; A communication method comprising:

[0364] Embodiment 32: The first type of measurement object includes M measurement objects, the second type of measurement object includes N measurement objects, both M and N are positive integers, and the measurement result of the first type of measurement object does not satisfy the first condition; All values ​​of the measurement results of the M measurement objects are less than the first threshold value, or a value of a measurement result of a first measurement object among the M measurement objects is less than a first threshold value; 32. The method of embodiment 31.

[0365] Embodiment 33: When the measurement result of the first type of measurement object does not satisfy the first condition includes that the value of the measurement result of the first measurement object among the M measurement objects is less than a first threshold value, the step of measuring the second type of measurement object includes: measuring K measurement objects among the N measurement objects, where the K measurement objects have an association relationship with the first measurement object, and K is a positive integer less than or equal to N; 33. The method of embodiment 32, comprising:

[0366] Embodiment 34: The method according to any one of embodiments 31 to 33, wherein the method further comprises a step of skipping measurement of the second type of measured object if the measurement result of the first type of measured object satisfies the first condition.

[0367]

[0081] Embodiment 35: A communication method for application to a remote device, comprising: receiving configuration information from the access network device, the configuration information being used to configure measurement events, the measurement events including a measurement result value of a first type of measurand being less than a first threshold and a measurement result value of a second type of measurand being equal to or greater than a second threshold, and a communication path of a remote device corresponding to the first type of measurand being different from a communication path of a remote device corresponding to the first type of measurand; Measuring a first type of measurement object and a second type of measurement object; sending a measurement result of the first type of measurement object and / or a measurement result of the second type of measurement object to the access network device based on the measurement event; A communication method comprising:

[0368]

[0081] Embodiment 36: The step of transmitting the measurement result of the first type of measurement object and / or the measurement result of the second type of measurement object to the access network device based on the measurement event includes: sending the measurement result of the second type of measurand to the access network device if the value of the measurement result of the first type of measurand is less than the first threshold and the value of the measurement result of the second type of measurand is greater than or equal to the second threshold; or transmitting the measurement result of the first type of measurement object to the access network device if the value of the measurement result of the first type of measurement object is equal to or greater than a first threshold value; 36. The method of embodiment 35, comprising:

[0369] Embodiment 37: The first type of measurement object is an air interface measurement object and the second type of measurement object is a sidelink measurement object; or The first type of measurement object is a sidelink measurement object and the second type of measurement object is an air interface measurement object. The method of embodiment 35 or 36.

[0370]

[0081] Embodiment 38: A communication method for application to a remote device, comprising: receiving configuration information from the access network device, the configuration information being used to configure a first measurement event, a second measurement event, and a third measurement event, the first measurement event including a measurement result value of a first type of measurand being less than a first threshold, the second measurement event including a measurement result value of a second type of measurand being greater than or equal to a second threshold, and the third measurement event including a measurement result value of the first type of measurand being greater than or equal to the first threshold, and a communication path of the remote device corresponding to the first type of measurand being different from a communication path of the remote device corresponding to the first type of measurand; Measuring a first type of measurement object and a second type of measurement object; sending a measurement result of the first type of measurement object and / or a measurement result of the second type of measurement object to the access network device based on the first measurement event, the second measurement event, and the third measurement event; A communication method comprising:

[0371] Embodiment 39: The step of transmitting a measurement result of a first type of measurement object and / or a measurement result of a second type of measurement object to an access network device according to the first measurement event, the second measurement event, and the third measurement event includes: sending the measurement result of the first type of measurand to the access network device if the value of the measurement result of the first type of measurand is less than a first threshold; sending the measurement result of the first type of measurand to the access network device if the value of the measurement result of the first type of measurand is greater than or equal to a first threshold value; or transmitting the measurement result of the second type of measurement object to the access network device if the value of the measurement result of the second type of measurement object is equal to or greater than the second threshold value; 39. The method of embodiment 38, comprising one or more of:

[0372] Embodiment 40: The first type of measurement object is an air interface measurement object and the second type of measurement object is a sidelink measurement object; or The first type of measurement object is a sidelink measurement object and the second type of measurement object is an air interface measurement object. 40. The method of embodiment 38 or 39.

[0373] Embodiment 41: A communication device, comprising: one or more processors; one or more memories; One or more computer programs stored in one or more memories, the one or more computer programs including instructions that, when executed by one or more processors of the communication device, enable the communication device to perform the method according to any one of embodiments 1 to 11, or enable the communication device to perform the method according to any one of embodiments 12 to 18, or enable the communication device to perform the method according to any one of embodiments 31 to 34, or enable the communication device to perform the method according to any one of embodiments 35 to 37, or enable the communication device to perform the method according to any one of embodiments 38 to 10; and 2. A communication device comprising:

[0374] Embodiment 42: A communication device, comprising: one or more processors; one or more memories; One or more computer programs stored in one or more memories, the one or more computer programs including instructions that, when executed by one or more processors of the communication device, enable the communication device to perform the method according to any one of embodiments 19 to 24, or enable the communication device to perform the method according to any one of embodiments 25 to 28, or enable the communication device to perform the method according to embodiment 29 or 30; and 2. A communication device comprising:

[0375] Embodiment 43: A computer-readable storage medium, the computer-readable storage medium being configured to store a computer program, which, when run on a computer, enables the computer to perform the method according to any one of embodiments 1 to 11, or enables the computer to perform the method according to any one of embodiments 12 to 18, or enables the computer to perform the method according to any one of embodiments 31 to 34, or enables the computer to perform the method according to any one of embodiments 35 to 37, or enables the computer to perform the method according to any one of embodiments 38 to 10, or enables the computer to perform the method according to any one of embodiments 19 to 24, or enables the computer to perform the method according to any one of embodiments 25 to 28, or enables the computer to perform the method according to embodiment 29 or 30.

[0376] Embodiment 44: A chip including one or more processors and a communication interface, wherein the one or more processors are configured to read instructions and perform a method according to any one of embodiments 1 to 11, or perform a method according to any one of embodiments 12 to 18, or perform a method according to any one of embodiments 31 to 34, or perform a method according to any one of embodiments 35 to 37, or perform a method according to any one of embodiments 38 to 10, or perform a method according to any one of embodiments 19 to 24, or perform a method according to any one of embodiments 25 to 28, or perform a method according to embodiment 29 or 30.

[0377] Embodiment 45: An apparatus comprising a unit for performing the method according to any one of the embodiments of the present application.

[0378] Embodiment 46: A computer program product, the computer program product comprising a computer program, which when run on a computer, enables the computer to perform the method according to any one of embodiments 1 to 11, or enables the computer to perform the method according to any one of embodiments 12 to 18, or enables the computer to perform the method according to any one of embodiments 31 to 34, or enables the computer to perform the method according to any one of embodiments 35 to 37, or enables the computer to perform the method according to any one of embodiments 38 to 10, or enables the computer to perform the method according to any one of embodiments 19 to 24, or enables the computer to perform the method according to any one of embodiments 25 to 28, or enables the computer to perform the method according to embodiment 29 or 30. [Explanation of symbols]

[0379] 1 System Information Block 17 Release S201 Step S202 Step S203 Step S204 Step S205 Step S206 Step S300 Step S301 Step S302 Step S302a Step S302b Step S302c Step S303 Step S304 Step S305 Step S306 Step S307 Step S308 Step S309 Step S400 Step S401 Step S402 Step S403 Step S404 Step S405 Step S406 Step S407 Step S408 Step S409 Step S410 Step S500 Step S501 Step S502 Step S503 Step S504 Step S505 Step S506 Step S507 Step S508 Step S509 Step S601a Step S601b Step S602 Step 700 Communication Equipment 701 Processor 702 Communication Line 703 Memory 704 Communication Interface 708 Processor 800 equipment 801 Transmitter Unit 802 Processing Unit 803 Receiver Unit

Claims

1. A communication method applied to a terminal device, the method comprising: Obtaining frequency information of a first cell, the first cell being a cell in which a first relay device is located; determining the first cell based on the frequency information of the first cell and an identifier of the first cell; determining whether the terminal device can serve as a remote device in the first cell based on a measurement result of the first cell; A communication method comprising:

2. The identifier of the first cell includes a physical cell identity PCI of the first cell or a new radio cell identity NCI of the first cell; The method of claim 1.

3. The step of obtaining frequency information of a first cell further comprises: receiving a first message from the first intermediate device, the first message including the frequency information of the first cell; 3. The method of claim 1 or 2, comprising:

4. The step of obtaining frequency information of a first cell further comprises: sending a second message to the first relay device, the second message being used to inquire about frequency information of the cell in which the first relay device is located, or to inquire whether the first relay device has camped on a cell at a first frequency, the first cell being the cell at the first frequency; receiving a first message from the first relay device, the first message including the frequency information of the first cell or the first message indicating that the first relay device has camped on the cell at the first frequency; 3. The method of claim 1 or 2, comprising:

5. The first message comprises: A discovery message, or PC5 Radio Resource Control (RRC) messages, or an RRC message from a serving access network device of the first relay device; 5. The method according to claim 3 or 4.

6. the first message further includes the identifier of the first cell.

6. The method according to any one of claims 3 to 5.

7. The method of claim 3 , wherein the first message further comprises first information, the first information indicating that the first cell is not in an access-barred state.

8. 8. The method of claim 3, wherein the first message further includes second information, the second information indicating whether searching for accessible cells on a frequency of the first cell is permitted when the first cell is in the access barred state.

9. A communication method applied to a first relay device, the method comprising: transmitting a discovery message, the discovery message including frequency information of a first cell, the first cell being a serving cell of the first relay device, the frequency information of the first cell being used by the remote terminal device to perform measurements to determine whether the remote terminal device can serve as a remote device in the first cell; A communication method comprising:

10. A communication method for application to a remote device, the method comprising: receiving configuration information from a first access network device, the configuration information being used to configure a measurement frequency on a sidelink and to configure cell information or air interface frequency information; measuring a first type of relay device based on the configuration information, where the first type of relay device is a relay device that operates at the measurement frequency and has camped on or can camp on a cell corresponding to the cell information, or the first type of relay device is a relay device that operates at the measurement frequency and has camped on or can camp on a cell at a frequency corresponding to the air interface frequency information; transmitting measurement results to the first access network device, the measurement results being used to determine a communication path for the remote device; A communication method comprising:

11. The method further comprising: receiving a fourth message from a first relay device, the fourth message including information about a first frequency, the first frequency being a frequency of a cell in which the first relay device is located or a frequency of a cell on which the first relay device can camp; 11. The method of claim 10, further comprising:

12. The fourth message is a discovery message or a PC5 RRC message. The method of claim 11.

13. said step of measuring a first type of intermediate device based on said configuration information further comprising: measuring or measuring and reporting the first relay device if the first frequency belongs to a frequency corresponding to the air interface frequency information configured based on the configuration information, or if a cell corresponding to the cell information configured based on the configuration information belongs to the first frequency.

13. The method of claim 11 or 12, comprising:

14. The method further comprising: sending a fifth message to the first relay device, the fifth message being used to inquire about frequency information of a cell in which the first relay device is located, or to inquire about frequency information of a cell on which the first relay device can camp, or to inquire whether the first relay device has camped on or can camp on a cell at a second frequency, the second frequency being a frequency corresponding to the air interface frequency information configured based on the configuration information; receiving a sixth message from the first relay device, the sixth message including information about the second frequency or the sixth message indicating that the first relay device has camped on or can camp on the cell at the second frequency; 11. The method of claim 10, further comprising:

15. The method further comprising: receiving an RRC reconfiguration message from the first access network device, the RRC reconfiguration message instructing the remote device to handover to a second cell, or instructing the remote device to handover to the first relay device, or instructing the remote device to add a second cell as a secondary cell, or instructing the remote device to add a path for communicating with a network using the first relay device, the first relay device being one of the first type of relay devices; 15. The method of any one of claims 10 to 14, further comprising:

16. The method of claim 15, wherein the RRC reconfiguration message further includes a PCI of the cell in which the first relay device is located.

17. The method of claim 15 or 16, wherein the RRC reconfiguration message further includes the frequency information of the cell in which the first relay device is located.

18. The method further comprising: receiving, from the first intermediate device, a PCI of the cell in which the first intermediate device is located, after establishing a connection with the first intermediate device; 16. The method of claim 15, further comprising:

19. The method further comprising: sending first instruction information to the first relay device after establishing the connection to the first relay device, the first instruction information instructing the first relay device to reselect a cell corresponding to the cell information configured based on the configuration information, or instructing the first relay device to reselect a cell at a frequency corresponding to the air interface frequency information configured based on the configuration information; 19. The method of any one of claims 15 to 18, further comprising:

20. said step of receiving configuration information from a first access network device further comprising: receiving the configuration information from the first access network device using a second intermediate device; 20. The method of any one of claims 10 to 19, comprising:

21. A communication method applied to a first relay device, the method comprising: transmitting information about a third frequency to a remote device, the third frequency being a frequency of a cell in which the first relay device is located or a frequency of a cell on which the first relay device can camp, the information about the third frequency being used to determine a communication path for the remote device; A communication method comprising:

22. said step of transmitting information regarding the third frequency to a remote device further comprising: transmitting a fourth message to the remote device, the fourth message including the information regarding the third frequency; 22. The method of claim 21 , comprising:

23. The fourth message is a discovery message or a PC5 RRC message.

23. The method of claim 22.

24. the third frequency being the frequency of the cell on which the first relay device can camp, and the method further comprising: receiving first indication information from the remote device after establishing a connection to the remote device, and reselecting a cell on the third frequency based on the first indication information; or receiving second indication information from a first access network device, and handing over to a cell at the third frequency based on the second indication information; 24. The method of claim 22 or 23, further comprising:

25. The method further comprising: receiving a fifth message from the remote device, the fifth message being used to inquire about frequency information of the cell in which the first relay device is located, or to inquire about frequency information of the cell on which the first relay device can camp, or to inquire whether the first relay device has camped on or can camp on a cell at a third frequency; Including, the step of transmitting information regarding the third frequency to a remote device includes a step of transmitting a sixth message to the remote device, the sixth message including the information regarding the third frequency or the sixth message indicating that the first relay device has camped on or can camp on the cell at the third frequency; The method of claim 21.

26. the third frequency being the frequency of the cell on which the first relay device can camp, and the method further comprising: reselecting the cell on the third frequency.

26. The method of claim 25, further comprising:

27. The method further comprising: after establishing the connection to the remote device, transmitting to the remote device a PCI of the cell in which the first intermediate device is located.

27. The method of any one of claims 21 to 26, further comprising:

28. 1. A communications device, comprising: one or more processors; one or more memories; one or more computer programs stored in the one or more memories, the one or more computer programs comprising instructions that, when executed by the one or more processors of the communications device, enable the communications device to perform a method according to any one of claims 1 to 8, or enable the communications device to perform a method according to claim 9, or enable the communications device to perform a method according to any one of claims 10 to 20, or enable the communications device to perform a method according to any one of claims 21 to 27; and A communication device comprising:

29. A computer readable storage medium, the computer readable storage medium configured to store a computer program, which when run on a computer enables the computer to perform the method according to any one of claims 1 to 8, or enables the computer to perform the method according to claim 9, or enables the computer to perform the method according to any one of claims 10 to 20, or enables the computer to perform the method according to any one of claims 21 to 27.

30. A chip comprising one or more processors and a communication interface, the one or more processors configured to: execute a method according to any one of claims 1 to 8, or to execute a method according to claim 9, or to execute a method according to any one of claims 10 to 20, or to read instructions for executing a method according to any one of claims 21 to 27.

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