Communication method and apparatus

Abstract

The present application provides a communication method and an apparatus. The method includes a step in which a central unit of a first network device sends a first indication information to a terminal device through a distributed unit of the first network device, the first indication information indicates a first resource of a configured grant of the terminal device, the first resource is associated with a first synchronization signal broadcast channel block SSB, and the first SSB is used by the terminal device in an inactive state to determine whether to transmit data using the first resource. In this way, when transmitting small data in an inactive state, the terminal device in an inactive state can determine whether the first resource of the configured grant is valid through the SSB, so that the terminal device transmits small data more quickly in an inactive state.

Description

Technical Field

[0002] Embodiments of the present application relate to the field of communication technologies, and in particular, to communication methods and devices.

Background Art

[0003] In the discussion of the 5th generation (5G), it has been decided to introduce a new radio resource control (RRC) state, namely the inactive state, into the standard. In order to obtain a power-saving effect similar to the idle state, the terminal device interrupts the radio resource control (RRC) connection to the network. Different from the idle state, in the inactive state, the terminal device and the access network device store the context of the terminal device. When the terminal device needs to enter the connected state, for example, when the terminal device needs to transmit uplink data, or when the network device pages the terminal device to enter the connected state, the terminal device enters the connected state based on the stored context of the terminal device, thereby reducing latency and signaling overhead.

[0004] In this way, a terminal device in the idle state or the inactive state needs to enter the connected state to transmit data to the network device. Even for small data packets that are not frequently transmitted, unnecessary power consumption and signaling overhead occur. Therefore, in one possible way, when transmitting small data in the inactive state, the terminal does not need to enter the connected state.

[0005] After the terminal leaves the coverage of the original access network device that stores the context, it is considered necessary for the terminal to initiate an RRC resume procedure to a new access network device. In particular, when the access network device includes a centralized unit (CU) and one or more distributed units (DUs), a method for appropriately managing the resources (e.g., context) of the terminal in this scenario, that is, a method for ensuring that the transmission of small data is not affected during the movement process of the terminal in the CU-DU split scenario, is still under discussion.

Summary of the Invention

Means for Solving the Problems

[0006] Embodiments of the present application provide a communication method and apparatus for improving the small data transmission performance of a terminal device in the movement process of the terminal device.

[0007] According to a first aspect, the present application provides a communication method, which includes a step in which a central unit of a first network device transmits first indication information to a terminal device via a distributed unit of the first network device. The first indication information indicates a first resource of a configured grant of the terminal device, and the first resource is associated with a first synchronization signal broadcast channel block (SSB). The first SSB is used by the terminal device to determine whether to transmit data using the first resource in a non-active state.

[0008] According to the foregoing method, when the first network device indicates the first resource of the configured grant to the terminal device, the corresponding resource may be associated with the SSB. For example, the first SSB is associated with the first resource. As a result, the terminal device can determine whether to use the first resource to transmit data in the inactive state by using the first SSB associated with the first resource. Thereby, the network device cannot send additional signaling to the terminal device to indicate when the terminal device transmits small data using the configured grant resource. In addition, the terminal device does not need to enter the connected state to receive the relevant signaling. Thereby, the transmission efficiency of small data by the terminal device in the inactive state is improved, and the transmission delay of small data by the terminal device in the inactive state is reduced.

[0009] In a possible implementation, that the first SSB is used by the terminal device to determine whether to transmit data using the first resource in the inactive state includes that the reference signal receiving power (RSRP) of the first SSB determines whether the uplink synchronization of the first resource is invalid, and when it is determined that the uplink synchronization of the first resource is valid, it is determined to transmit data using the first resource, or when it is determined that the uplink synchronization of the first resource is invalid, it is determined not to transmit data using the first resource.

[0010] According to the foregoing method, based on whether the uplink synchronization of the first SSB is invalid, it is determined whether the first resource of the configured grant associated with the first SSB, which is used for small data transmission, can be used by the terminal device to transmit small data in the inactive state. Therefore, the signaling interaction between the terminal device and the first network device can be reduced, the transmission performance of small data in the inactive state can be improved, and the transmission delay can be reduced.

[0011] Optionally, when it is determined that the uplink synchronization of the first resource is invalid, it is determined to release the first resource. Therefore, the terminal device can release the corresponding resource in a timely manner, and the terminal device is prevented from transmitting small data using invalid resources, thereby improving the transmission success rate of the terminal device.

[0012] In a possible implementation, the use of the RSRP of the first SSB to determine whether the uplink synchronization of the first resource is invalid includes that when the RSRP of the first SSB is greater than or equal to the first threshold, it is determined that the uplink synchronization of the first resource is valid. When the increase variation of the RSRP of the first SSB is greater than or equal to the second threshold, or when the decrease variation of the RSRP of the first SSB is greater than or equal to the third threshold, it is determined that the uplink synchronization of the first resource is invalid.

[0013] According to the foregoing method, whether the first SSB is invalid can be determined based on the RSRP of the first SSB to correspondingly determine whether the first resource of the configured grant associated with the first SSB, which is used for small data transmission, can be used by the terminal device to transmit small data in the inactive state. By determining that the SSB is invalid and determining the SSB associated with the configured grant resource, the complexity for the terminal to determine whether the transmission resource is valid can be reduced, and the transmission efficiency can be improved.

[0014] In a possible implementation form, the central unit of the first network device transmits second instruction information to the terminal device via the distributed unit of the first network device. The second instruction information indicates a second resource of the configured grant of the terminal device, and the second resource is used by the terminal device to transmit data using the second resources in the inactive state and the connected state.

[0015] According to the above method, in the switching process between the inactive state and the connected state, the terminal device can transmit small data using the indicated second resource regardless of whether the terminal device is in the inactive state or the connected state. Thereby, the influence of the switching process on small data transmission is avoided, and it is not necessary to reconfigure the corresponding resources for the terminal device after switching, thereby improving the efficiency and performance of small data transmission by the terminal device.

[0016] In a possible implementation form, the central unit of the first network device transmits the context of the terminal device in the inactive state to the second network device. The central unit of the first network device transmits a first message to the distributed unit of the first network device, and the first message indicates to the distributed unit of the first network device to release the context of the terminal device.

[0017] According to the foregoing method, in the process of the central unit of the first network device transmitting the context of the terminal device in the inactive state to the second network device, the first network device may determine that the terminal device is currently being handed over to the second network device in order to indicate that the distributed unit of the first network device releases the context of the terminal device in a timely manner. In this way, when the terminal device is handed over to the second network device, the distributed unit of the first network device can release the context of the terminal device in a timely manner in the process of the terminal device transmitting small data. Thereby, the utilization of resources corresponding to the context of the terminal device by the distributed unit of the first network device is improved, and the overall network performance is improved.

[0018] In a possible implementation form, before the central unit of the first network device transmits the context of the terminal device in the inactive state to the second network device, the method further includes the step of the central unit of the first network device receiving a context search request of the terminal device from the second network device.

[0019] According to the foregoing method, based on the context search request of the terminal device transmitted by the second network device, the first network device may determine that the second network device is the network device to which the terminal device should be handed over. This helps the first network device manage the context of the terminal device, reduces the resource overhead while ensuring that the terminal device can normally transmit small data in the handover process.

[0020] In one possible implementation, before the central unit of the first network device sends the context of the terminal device in the inactive state to the second network device, the method further includes a step of the central unit of the first network device successfully verifying the identity of the second network device.

[0021] According to the foregoing method, after successfully verifying the identity of the second network device, the central unit of the first network device instructs the distributed unit of the first network device to release the context of the terminal device. Thereby, when the security of the second network device is guaranteed, that is, when the terminal device can be successfully handed over to the second network device, the resource overhead is reduced, and the problem that the terminal device may be frequently handed over to the network device is avoided.

[0022] In one possible implementation, the context includes a configured grant configured for the terminal device, configuration information of a physical downlink control channel (PDCCH) configured for the terminal device, a temporary identifier for scrambling the PDCCH, an inactive radio network temporary identity (I-RNTI) for the terminal device, and configuration information of a radio link control (RLC) layer corresponding to a radio bearer configured for the terminal device including one or more of the foregoing.

[0023] According to a second aspect, the present application provides a communication method. A second network device transmits first indication information to a terminal device. The first indication information indicates a first resource of a configured grant of the terminal device, the first resource is associated with a first SSB, and the first SSB is used by the terminal device to determine whether to transmit data using the first resource in a non-active state of the terminal device.

[0024] It should be noted that the second network device may be a network device to which the terminal device is handed over from a first network device, or may be a network device before the terminal device is handed over from the first network device. According to the foregoing method, when the second network device indicates the first resource of the configured grant to the terminal device, the corresponding resource may be associated with the SSB. For example, the first SSB is associated with the first resource, and as a result, the terminal device may use the first SSB associated with the first resource to determine whether to transmit data using the first resource in a non-active state. Thereby, the network device cannot transmit additional signaling to the terminal device to indicate when the terminal device transmits small data using the configured grant resource. In addition, the terminal device does not need to enter a connected state to receive the relevant signaling. Thereby, the transmission efficiency of small data by the non-active terminal device is improved, and the transmission delay of small data by the non-active terminal device is reduced.

[0025] In a possible implementation form, whether the first SSB is used by the terminal device to determine whether to transmit data using the first resource in the inactive state includes that the RSRP of the first SSB is used to determine whether the uplink synchronization of the first resource is invalid, and when it is determined that the uplink synchronization of the first resource is valid, it is determined to transmit data using the first resource, or when it is determined that the uplink synchronization of the first resource is invalid, it is determined to release the first resource.

[0026] In a possible implementation form, that the RSRP of the first SSB is used to determine whether the uplink synchronization of the first resource is invalid includes that when the RSRP of the first SSB is greater than or equal to the first threshold, it is determined that the uplink synchronization of the first resource is valid. When the increase variation of the RSRP of the first SSB is greater than or equal to the second threshold, or when the decrease variation of the RSRP of the first SSB is greater than or equal to the third threshold, it is determined that the uplink synchronization of the first resource is invalid.

[0027] In a possible implementation form, the second network device transmits second indication information to the terminal device. The second indication information indicates the second resource of the configured grant of the terminal device, and the second resource is used by the terminal device to transmit data using the second resources in the inactive state and the connected state.

[0028] According to the above method, in the switching process between the inactive state and the connected state, the terminal device can transmit small data using the indicated second resource regardless of whether the terminal device is in the inactive state or the connected state. Thereby, the influence of the switching process on small data transmission is avoided, and it is not necessary to reconfigure the corresponding resources for the terminal device after switching, thereby improving the efficiency and performance of small data transmission by the terminal device.

[0029] In one possible implementation, the second network device receives the context of the terminal device in an inactive state from the central unit of the first network device. The context is used by the second network device to restore the terminal device to a connected state.

[0030] According to the foregoing method, when the second network device determines that the terminal device is currently being switched from an inactive state to a connected state, the second network device may obtain the context of the terminal device from the central unit of the first network device before the switch. As a result, the terminal device does not need to restart access in the process of switching from an inactive state to a connected state, and may transmit small data based on the second resources configured by the second network device, thereby avoiding the impact of the state switching process of the terminal device on small data transmission.

[0031] In one possible implementation, the context includes one or more of a configured grant configured for the terminal device, configuration information of a PDCCH configured for the terminal device, a temporary identifier for scrambling the PDCCH, an I-RNTI configured for the terminal device, and configuration information of an RLC layer corresponding to a radio bearer configured for the terminal device.

[0032] According to a third aspect, the present application provides a communication method. The terminal device receives first indication information transmitted by the central unit of the first network device via a distributed unit of the first network device. The first indication information indicates a first resource of a configured grant of the terminal device, and the first resource is associated with a first SSB. The terminal device determines whether to transmit data using the first resource in an inactive state based on the first SSB.

[0033] According to the foregoing method, the first SSB is associated with the first resource. As a result, in the inactive state, the terminal device can determine whether to use the first resource to transmit data to the terminal device, for example, by using the first SSB associated with the first resource, based on the first resource of the configured grant indicated by the first network device and the corresponding resource associated with the SSB. Thereby, the network device cannot send additional signaling to the terminal device to indicate when the terminal device transmits small data using the configured grant resource. In addition, the terminal device does not need to enter the connected state to receive the relevant signaling. Thereby, the transmission efficiency of small data by the terminal device in the inactive state is improved, and the transmission delay of small data by the terminal device in the inactive state is reduced.

[0034] According to a fourth aspect, a communication method is provided. The terminal device receives first indication information transmitted by a second network device. The first indication information indicates the first resource of the configured grant of the terminal device, and the first resource is associated with the first SSB. The terminal device determines whether to transmit data using the first resource in an inactive state based on the first SSB.

[0035] It should be noted that the second network device may be the network device to which the terminal device is handed over from the first network device, or may be the network device before the terminal device is handed over from the first network device.

[0036] According to the foregoing method, after the terminal device is handed over from the first network device to the second network device, the first SSB is associated with the first resource. As a result, in the inactive state, the terminal device can determine whether to transmit data using the first resource, for example, by using the first SSB associated with the first resource, based on the first resource of the configured grant indicated by the second network device and the corresponding resource associated with the SSB. Thereby, the transmission efficiency of small data by the terminal device in the inactive state is improved, and the transmission delay of small data by the terminal device in the inactive state is reduced. In addition, after the terminal device is handed over from the second network device to the first network device, the terminal device can still determine whether it can transmit small data based on the first resource configured by the second network device for the terminal device, and the first network device does not need to reconfigure the corresponding configured grant small data resource. Thereby, the transmission performance of small data by the terminal device is improved.

[0037] In relation to the third or fourth aspect, in a possible implementation, for the terminal device to determine whether to transmit data using the first resource in the inactive state based on the first SSB includes the terminal device determining whether the uplink synchronization of the first resource is invalid based on the reference signal received power RSRP of the first SSB. When it is determined that the uplink synchronization of the first resource is valid, the terminal device determines to transmit data using the first resource. When it is determined that the uplink synchronization of the first resource is invalid, the terminal device determines not to transmit data using the first resource.

[0038] In relation to the third or fourth aspect, in a possible implementation, when the terminal device determines that the uplink synchronization of the first resource is invalid, the terminal device releases the first resource.

[0039] In relation to the third or fourth aspect, in one possible implementation, for the terminal device to determine whether uplink synchronization of the first resource is invalid based on the RSRP of the first SSB includes that when the RSRP of the first SSB is greater than or equal to the first threshold, the terminal device determines that the uplink synchronization of the first resource is valid. When the increase variation of the RSRP of the first SSB is greater than or equal to the second threshold, or when the decrease variation of the RSRP of the first SSB is greater than or equal to the third threshold, the terminal device determines that the uplink synchronization of the first resource is invalid.

[0040] In relation to the third aspect, in one possible implementation, the terminal device receives second indication information transmitted by the central unit of the first network device via the distributed unit of the first network device. The second indication information indicates the second resource of the configured grant of the terminal device, and the second resource is used by the terminal device to transmit data using the second resources in the inactive state and the connected state.

[0041] In relation to the third and / or fourth aspect, in one possible implementation, the terminal device receives second indication information transmitted by the second network device. The second indication information indicates the second resource of the configured grant of the terminal device, and the second resource is used by the terminal device to transmit data using the second resources in the inactive state and the connected state.

[0042] According to the above method, in the switching process between the inactive state and the connected state, the terminal device can transmit small data using the indicated second resource regardless of whether the terminal device is in the inactive state or the connected state. Thereby, the influence of the switching process on small data transmission is avoided, and it is no longer necessary to reconfigure the corresponding resources for the terminal device after switching, thereby improving the efficiency and performance of small data transmission by the terminal device.

[0043] In relation to the third aspect and / or the fourth aspect, in a possible implementation, the terminal device is restored to the connected state using the context of the terminal device obtained by the second network device, and the context of the terminal device is obtained by the second network device receiving it and is from the central unit of the first network device.

[0044] According to the fifth aspect, the present application provides a communication method. The central unit of the first network device transmits the context of the inactive terminal device to the second network device. The central unit of the first network device transmits a first message to the distributed unit of the first network device, and the first message indicates to the distributed unit of the first network device to release the context of the terminal device.

[0045] According to the foregoing method, in the process of the central unit of the first network device transmitting the context of the terminal device in the inactive state to the second network device, the first network device may determine that the terminal device is currently being handed over to the second network device in order to indicate that the distributed unit of the first network device releases the context of the terminal device in a timely manner. In this way, when the terminal device is handed over to the second network device, the distributed unit of the first network device can release the context of the terminal device in a timely manner in the process of the terminal device transmitting small data. Thereby, the utilization of the resources corresponding to the context of the terminal device by the distributed unit of the first network device is improved, and the overall network performance is improved.

[0046] In a possible implementation form, before the central unit of the first network device transmits the context of the terminal device in the inactive state to the second network device, the method further includes the step of the central unit of the first network device receiving a context search request of the terminal device from the second network device.

[0047] According to the foregoing method, based on the context search request of the terminal device transmitted by the second network device, the first network device may determine that the second network device is the network device to which the terminal device should be handed over. This helps the first network device manage the context of the terminal device, reduces the resource overhead while ensuring that the terminal device can normally transmit small data in the handover process.

[0048] In one possible implementation, before the central unit of the first network device transmits the context of the terminal device in the inactive state to the second network device, the method further includes a step of the central unit of the first network device validating the identity of the second network device normally.

[0049] According to the foregoing method, after the identity of the second network device is normally verified, the central unit of the first network device instructs the distributed unit of the first network device to release the context of the terminal device. Thereby, when the security of the second network device is guaranteed, that is, when the terminal device can be normally handed over to the second network device, the resource overhead is reduced, and the problem that the terminal device may be frequently handed over to the network device is avoided.

[0050] In one possible implementation, the context is a configured grant configured for the terminal device, the configuration information of the PDCCH configured for the terminal device, a temporary identifier for scrambling the PDCCH, an inactive radio network temporary identifier I-RNTI configured for the terminal device, and the configuration information of the RLC layer corresponding to the radio bearer configured for the terminal device, includes one or more of the above.

[0051] In one possible implementation, the terminal device in the inactive state is configured to transmit data to the first network device.

[0052] According to a sixth aspect, the present application provides a communication device used in a first network device. The first network device may include a central unit and a distributed unit. The central unit may include a processing module, a transmission module, and a reception module.

[0053] In some embodiments, the processing module of the central unit is configured to use the transmission module of the central unit to transmit first indication information to a terminal device via the distributed unit of the first network device. The first indication information indicates a first resource of a configured grant of the terminal device, and the first resource is associated with a first SSB. The first SSB is used by the terminal device to determine whether to transmit data using the first resource in a non-active state.

[0054] In a possible implementation, the processing module of the central unit is configured to use the transmission module of the central unit to transmit the context of a non-active terminal device to a second network device. The processing module of the central unit is configured to use the transmission module of the central unit to transmit a first message to the distributed unit of the first network device. The first message indicates to the distributed unit of the first network device to release the context of the terminal device.

[0055] In a possible implementation, before using the transmission module of the central unit to transmit the context of a non-active terminal device to a second network device, the processing module of the central unit is further configured to use the reception module of the central unit to receive a context search request of the terminal device from the second network device.

[0056] In one possible implementation, before the processing module of the central unit uses the transmission module of the central unit to send the context of the terminal device in the inactive state to the second network device, the processing module of the central unit is further configured to successfully verify the identity of the second network device.

[0057] In some other embodiments, the processing module of the central unit is configured to use the transmission module of the central unit to send the context of the terminal device in the inactive state to the second network device. The processing module of the central unit is configured to use the transmission module of the central unit to send a first message to the distributed unit of the first network device. The first message indicates to the distributed unit of the first network device to release the context of the terminal device.

[0058] In one possible implementation, before the processing module of the central unit is configured to use the transmission module of the central unit to send the context of the terminal device in the inactive state to the second network device, the processing module of the central unit is further configured to use the reception module of the central unit to receive a context search request for the terminal device from the second network device.

[0059] In one possible implementation, before the processing module of the central unit is configured to use the transmission module of the central unit to send the context of the terminal device in the inactive state to the second network device, the processing module of the central unit is further configured to successfully verify the identity of the second network device.

[0060] In one possible implementation, the context includes a configured grant configured for the terminal device, configuration information of a physical downlink control channel configured for the terminal device, and a temporary identifier for scrambling the physical downlink control channel. An inactive radio network temporary identifier configured for a terminal device, and configuration information of a radio link control layer corresponding to a radio bearer configured for the terminal device includes one or more of the above.

[0061] In a possible implementation, the terminal device in the inactive state is configured to transmit data to a first network device.

[0062] According to a seventh aspect, the present application provides a communication device used in a second network device. The second network device may include a processing module, a transmission module, and a reception module. The processing module is configured to transmit first indication information to the terminal device using the transmission module. The first indication information indicates a first resource of a configured grant of the terminal device, and the first resource is associated with a first SSB. The first SSB is used by the terminal device to determine whether to transmit data using the first resource in the inactive state of the terminal device.

[0063] In relation to the sixth aspect or the seventh aspect, in a possible implementation, the RSRP of the first SSB determines whether the uplink synchronization of the first resource is invalid. When it is determined that the uplink synchronization of the first resource is valid, it is determined to transmit data using the first resource, or when it is determined that the uplink synchronization of the first resource is invalid, it is determined to release the first resource. It is used for this purpose.

[0064] In relation to the sixth aspect or the seventh aspect, in a possible implementation, when the RSRP of the first SSB is greater than or equal to a first threshold, it is determined that the uplink synchronization of the first resource is valid. When the increase variation of the RSRP of the first SSB is greater than or equal to a second threshold, or when the decrease variation of the RSRP of the first SSB is greater than or equal to a third threshold, it is determined that the uplink synchronization of the first resource is invalid.

[0065] In relation to the sixth or seventh aspect, in one possible implementation, the processing module of the central unit is configured to use the transmission module of the central unit to transmit second instruction information to the terminal device via the distributed unit of the first network device. The second instruction information indicates a second resource of the configured grant of the terminal device, and the second resource is used by the terminal device to transmit data using the second resources in the inactive state and the connected state.

[0066] In relation to the sixth or seventh aspect, in one possible implementation, the context a configured grant configured for the terminal device, configuration information of the PDCCH configured for the terminal device, a temporary identifier for scrambling the PDCCH, an inactive radio network temporary identifier I-RNTI configured for the terminal device, and configuration information of the RLC layer corresponding to the radio bearer configured for the terminal device, includes one or more of the above.

[0067] According to the eighth aspect, the present application provides a communication device used in a terminal device or a chip of a terminal device. The communication device may include a processing module, a receiving module, and a transmitting module.

[0068] In some embodiments, the processing module is configured to use the receiving module to receive first instruction information transmitted by the central unit of the first network device via the distributed unit of the first network device. The first instruction information indicates a first resource of the configured grant of the terminal device, and the first resource is associated with the first SSB. The processing module is configured to determine whether to transmit data using the first resource in the inactive state based on the first SSB.

[0069] In some other embodiments, the processing module is configured to receive, using the receiving module, first indication information transmitted by a second network device. The first indication information indicates a first resource of a configured grant of the terminal device, and the first resource is associated with a first SSB. The terminal device determines whether to transmit data using the first resource in a non-active state based on the first SSB. Note that the second network device may be a network device to which the terminal device is handed over from a first network device, or may be a network device before the terminal device is handed over from the first network device.

[0070] In a possible implementation, the processing module determines, based on the reference signal received power RSRP of the first SSB, whether uplink synchronization of the first resource is invalid in a non-active state, and when it is determined that the uplink synchronization of the first resource is valid, determines to transmit data using the first resource, or when it is determined that the uplink synchronization of the first resource is invalid, determines not to transmit data using the first resource.

[0071] In a possible implementation, the processing module is configured to release the first resource when it is determined that the uplink synchronization of the first resource is invalid in a non-active state.

[0072] In a possible implementation, the processing module determines that the uplink synchronization of the first resource is valid when the RSRP of the first SSB is greater than or equal to a first threshold in a non-active state, or determines that the uplink synchronization of the first resource is invalid when the increase variation of the RSRP of the first SSB is greater than or equal to a second threshold, or when the decrease variation of the RSRP of the first SSB is greater than or equal to a third threshold.

[0073] In a possible implementation form, the processing module is configured to receive, via the distributed unit of the first network device, the second instruction information transmitted by the central unit of the first network device using the receiving module. The second instruction information indicates the second resource of the configured grant of the terminal device, and the second resource of the configured grant is used by the terminal device to transmit data using the second resources in the inactive state and the connected state.

[0074] In a possible implementation form, the processing module is configured to receive, using the receiving module, the second instruction information transmitted by the second network device. The second instruction information indicates the second resource of the configured grant of the terminal device, and the second resource is used by the terminal device to transmit data using the second resources in the inactive state and the connected state.

[0075] In a possible implementation form, the processing module is configured to be restored to the connected state using the context of the terminal device acquired by the second network device, where the context of the terminal device is acquired by the second network device receiving it and is from the central unit of the first network device.

[0076] According to the ninth aspect, an embodiment of the present application provides a communication device including a processor and a memory. The memory is configured to store computer-executable instructions. When the device operates, the processor executes the computer-executable instructions stored in the memory to enable the device to execute any method in the implementation form of the first aspect or the fifth aspect.

[0077] According to a tenth aspect, an embodiment of the present application provides a communication device including a processor and a memory. The memory is configured to store computer-executable instructions. When the device operates, the processor executes the computer-executable instructions stored in the memory to enable the device to execute any method in the implementation form of the second aspect.

[0078] According to an eleventh aspect, an embodiment of the present application provides a communication device including a processor and a memory. The memory is configured to store computer-executable instructions. When the device operates, the processor executes the computer-executable instructions stored in the memory to enable the device to execute any method in the implementation form of the third or fourth aspect.

[0079] According to a twelfth aspect, an embodiment of the present application further provides a computer-readable storage medium. The computer-readable storage medium stores instructions, and when the instructions are run on a computer, the computer is enabled to execute any method in the implementation form from the first aspect to the fifth aspect.

[0080] According to a thirteenth aspect, an embodiment of the present application further provides a computer program product. The computer product includes a computer program. When the computer program is executed, any method in the implementation form from the first aspect to the fifth aspect is executed.

[0081] According to a fourteenth aspect, an embodiment of the present application further provides a chip system including a processor configured to execute any method in the implementation form from the first aspect to the fifth aspect.

[0082] According to a fifteenth aspect, an embodiment of the present application further provides a communication system, the communication system including a first network device according to the sixth or ninth aspect, or a second network device according to the seventh or tenth aspect, or a terminal device according to the eighth or eleventh aspect.

Brief Description of the Drawings

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Modes for Carrying Out the Invention

[0084] To facilitate the understanding of those skilled in the art, several terms in the embodiments of the present application will be described below.

[0085] The technical solutions in the embodiments of this application can be applied to various communication systems, such as the 5th Generation mobile communication technology (5G) system (e.g., New Radio (NR)), Long Term Evolution (LTE) system, LTE Frequency Division Duplex (FDD) system, and LTE Time Division Duplex (TDD) system. This is not limited in this specification. The system architectures and service scenarios described in the embodiments of this application are intended to more clearly illustrate the technical solutions of the embodiments of this application and do not limit the technical solutions provided in the embodiments of this application. Those skilled in the art can know that due to the evolution of network architectures and the emergence of new service scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems on the condition that the radio access network devices in the communication system have a CU-DU split architecture or an architecture with functions equivalent to the CU-DU split architecture.

[0086] FIG. 1 is a schematic diagram of the network architecture of a communication system to which an embodiment of this application is applicable.

[0087] As shown in FIG. 1, the communication system includes terminal devices 1301 and 1302 and network devices.

[0088] The terminal device can access a wireless network and access services of an external network (e.g., the Internet) via the wireless network, or communicate with another device via the wireless network, for example, communicate with another terminal device. The access network may be a next generation radio access network (NG-RAN). The access network may include an access network device, for example, a base station (e.g., gNB). The gNB is connected via an interface (e.g., Xn interface). The RAN device is configured to connect the terminal device to the wireless network, and the gNB and 5GC are connected via an interface (e.g., Ng interface). The RAN may include one or more access network devices, for example, access network device 1101 and access network device 1102.

[0089] An access network device is a node or device that connects a terminal device to a wireless network, and an access network device may sometimes be called a base station. For example, the access network device includes, but is not limited to, a generation Node B (gNB) of a 5G communication system, an evolved node B (eNB), a radio network controller (RNC), a node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home evolved node B (HeNB) or a home node B (HNB), a baseBand unit (BBU), a transmitting and receiving point (TRP), a transmitting point (TP), or a mobile switching center of a 5G communication system.

[0090] The core network (CN) may include a plurality of core network devices. The core network devices are configured to manage terminal devices and provide a gateway for communicating with an external network. The CN may include one or more core network elements, such as core network element 120. When the network architecture shown in FIG. 1 is applicable to a 5G communication system, the core network may be a 5G core network (5GC). The 5GC includes one or more functions or devices. For example, the core network device may be an access and mobility management function (AMF) entity, a session management function (SMF) entity, or a user plane function (UPF) entity, etc., or a session management function (SMF). It will be understood that these functions or devices may be network elements within a hardware device, software functions executed on dedicated hardware, or virtualized functions instantiated on a platform (e.g., a cloud platform). It will be understood that the names of various core network devices are names in a 5G communication system. With the evolution of the communication system, the names may be changed to other names having the same function. When the network architecture shown in FIG. 1 is applicable to an LTE communication system, the core network device may be a mobility management entity (MME), a serving gateway (S-GW), etc.

[0091] A terminal device may also be referred to as a user equipment (UE), a mobile station (MS), a mobile terminal (MT), etc., and is a device that provides a user with voice or data connectivity and may be an Internet of Things device. For example, the terminal device may be a handheld device or an in-vehicle device having a wireless connection function. Currently, the terminal device may be a mobile phone, a tablet computer, a notebook computer, a palmtop computer, a mobile internet device (MID), a wearable device (e.g., a smartwatch, a smartband, or a pedometer), an in-vehicle device (e.g., an in-vehicle device on an automobile, a bicycle, an electric vehicle, an aircraft, a ship, a train, or a high-speed train), a virtual reality (VR) device, an augmented reality (AR) device, a wireless terminal device for industrial control, a smart home device (e.g., a refrigerator, a television, an air conditioner, or a power meter), an intelligent robot, a workshop device, a wireless terminal device for self-driving, a wireless terminal device for remote medical surgery, a wireless terminal device for a smart grid, a wireless terminal device for transportation safety, a wireless terminal device for a smart city, a wireless terminal device for a smart home, or a flying device (e.g., an intelligent robot, a hot air balloon, a drone, or an aircraft), etc. In the embodiments of the present application, a UE or a terminal device is used as an example for explaining the solution.

[0092] It should be understood that the number of devices in the communication system shown in FIG. 1 is only used as an example. This embodiment of the present application is not limited thereto. In actual applications, the communication system may further include more terminal devices and more RAN devices, and may further include other devices. In the embodiments of the present application, the device configured to implement the function of the access network device may be an access network device, or a device capable of supporting the access network device when implementing the function, for example, a chip system capable of implementing the function of the access network device, or a combined component or device. The device may be installed in the access network device. In the technical solutions provided in the embodiments of the present application, the technical solutions provided in the embodiments of the present application are described using an example in which the device configured to implement the function of the access network device is an access network device.

[0093] FIG. 2 is a schematic diagram of a network architecture in a 5G communication system to which an embodiment of the present application is applicable. As shown in FIG. 2, the network architecture includes a CN device (for example, 5GC shown in FIG. 2) and a RAN device.

[0094] In the new network architecture of the 5G NR network, the network device may include two logical network elements, a CU and a DU. Some functions of the network device are deployed in the CU, and the remaining functions are deployed in the DU. Multiple DUs can share one CU, which can save costs and facilitate network expansion. The CU and the DU can be deployed in an integrated manner or separately based on scenarios and requirements. The network architecture is hereinafter abbreviated as the CU-DU split architecture.

[0095] In an embodiment of the present application, the CU and the DU are connected via an interface (for example, the F1 interface). The CU indicates that the base station is connected to the core network via an interface (for example, the Ng interface). In the communication system of the present application, in relation to FIG. 2, the UE can be connected to an access network device (for example, a gNB). Specifically, the UE may be connected to the DU within the gNB. The CU is connected to the 5GC and the DU. In the downlink communication link, the CU is configured to receive data from the 5GC and transmit the data to the DU. In the uplink communication link, the CU is configured to receive data from the DU and transmit the data to the 5GC. In addition, the CU has a centralized control function for the DU. In a system using different radio access technologies, the device having the CU function may have a different name. For ease of explanation, the device having the CU function is generically referred to as the access network central unit.

[0096] The UE is connected to the CU and the user equipment (UE). In the downlink communication link, the DU is configured to receive data from the CU and transmit the data to the UE. In the uplink communication link, the DU is configured to receive data from the UE and transmit the data to the CU. In a system using different radio access technologies, the device having the DU function may have a different name. For ease of explanation, the device having the DU function is generically referred to as the access network distributed unit.

[0097] The communication between the RAN device and the terminal device complies with a specific protocol layer structure. For example, as shown in FIG. 3a, the control plane protocol layer structure may include the functions of protocol layers such as the radio resource control (RRC) layer, the packet data convergence protocol (PDCP) layer, the RLC layer, the media access control (MAC) layer, and the physical layer. The user plane protocol layer structure may include the functions of protocol layers such as the PDCP layer, the RLC layer, the MAC layer, and the physical layer. In a possible implementation form, a service data adaptation protocol (SDAP) layer may be further included above the PDCP layer. The main function of the RRC layer is the upper layer control of the UE, and it is related to the access control, maintenance, and release of the UE, as well as the UE configuration so that the RRC layer can analyze the RRC message. The main functions of the MAC layer and the physical layer (PHY) are the lower layer scheduling of the UE, and it is related to the data packet assembly and data scheduling of the UE so that the MAC layer can analyze the control signaling of the MAC layer and the PHY layer can analyze the control signaling of the PHY layer. The RAN device may implement the functions of protocol layers such as RRC, PDCP, RLC, and MAC using one node or multiple nodes.

[0098] In the case of the control plane, in the UL direction, the gNB-DU encapsulates the RRC message generated by the UE into an F1 AP message on the F1 interface and sends the F1 AP message to the gNB-CU. In the DL direction, the gNB-CU encapsulates the RRC message into an F1 AP message and sends the F1 AP message to the gNB-DU. The gNB-DU extracts the RRC message from the F1 AP message, maps the RRC message to the SRB corresponding to the Uu interface, and sends the RRC message to the UE.

[0099] In the case of the user plane, in the UL direction, the gNB-DU maps the UE data packets received from the DRB of the Uu interface to the corresponding GTP tunnel and sends the UE data packets to the gNB-CU. In the DL direction, the gNB-CU maps the UE data packets to the corresponding GTP tunnel, sends the UE data packets to the gNB-DU, and the gNB-DU extracts the UE data packets from the GTP tunnel, maps the UE data packets to the DRB corresponding to the Uu interface, and sends the UE data packets to the UE.

[0100] In the above-mentioned network architecture, the signaling generated by the CU may be sent to the terminal device using the DU, or the signaling generated by the terminal device may be sent to the CU using the DU. The DU may transparently transmit the signaling to the terminal device or the CU by directly encapsulating the signaling at the protocol layer without analyzing the signaling. In the following embodiments, when such signaling transmission between the DU and the terminal device is included, the transmission or reception of signaling by the DU includes this scenario. For example, the signaling in the RRC layer or the PDCP layer is finally processed as signaling in the physical layer and sent to the terminal device, or is converted from the signaling received from the physical layer. In this architecture, the signaling in the RRC layer or the PDCP layer may also be considered to be sent by the DU or sent by the DU and the radio frequency device.

[0101] The split between the CU of the network device and the DU of the network device based on the protocol stack can be shown in Figure 3b. For example, the RRC layer, the SDAP layer, and the PDCP layer are deployed in the CU of the network device. The RLC layer, the MAC layer, and the physical layer are deployed in the DU of the network device.

[0102] In an embodiment of the present application, when the network device is a device that supports the NR system, the functional split of the CU and DU may be performed based on the protocol stack. The CU of the network device and the DU of the network device are used as two functional entities. In one possible way, the functions of the CU and DU are distinguished based on the real-time performance of the processed content. As shown in FIG. 3b, the RRC layer, SDAP layer, and PDCP layer are deployed in the CU. Layers such as the RLC layer, MAC layer, and PHY layer are deployed in the DU. Correspondingly, the CU is capable of processing the RRC layer, PDCP layer, and SDAP layer. In the case of a network device having a CU-DU architecture, the CU of the network device plays a role in managing the RRC state of the terminal device. The DU is capable of processing the RLC, MAC, and PHY.

[0103] It should be noted that the above functional split is only an example, and it should be noted that there may be other split methods. For example, the CU is capable of processing the RRC layer, PDCP layer, RLC layer, and SDAP layer, and the DU is capable of processing the MAC layer and PHY layer. In another example, the CU is capable of processing a part of RRC, PDCP, RLC, SDAP, and MAC (for example, adding a MAC header), and the DU is capable of processing a part of PHY and MAC (for example, scheduling).

[0104] The split based on the protocol layer is just an example. Alternatively, the split may be performed based on another protocol layer such as the RLC layer. The functions of the RLC layer and the protocol layers above the RLC layer are set in the CU, and the functions of the protocol layers below the RLC layer are set in the DU. Alternatively, the split is performed at the protocol layer. For example, some functions of the RLC layer and the functions of the protocol layers above the RLC layer are set in the CU, and the remaining functions of the RLC layer and the functions of the protocol layers below the RLC layer are set in the DU. In addition, the split may alternatively be performed in another manner. For example, the split is performed based on latency. The functions that need to meet the latency requirement in terms of processing time are set in the DU, and the functions that do not need to meet the latency requirement in terms of processing time are set in the CU. The foregoing protocol layer split is merely an example, and the split may be performed in another protocol layer. Examples are not described one by one in this specification.

[0105] Naturally, the embodiments of the present application may be further applicable to an LTE communication system. For example, the LTE communication system may also include a RAN device and a CN device. The RAN device (eNB) includes a baseband device and a radio frequency device. The baseband device may be implemented by one node or by a plurality of nodes. The radio frequency device may be remotely implemented independently of the baseband device, integrated with the baseband device, or a part of the radio frequency device is remotely implemented from the baseband device and the remaining part is integrated with the baseband device. The radio frequency device may be remotely located from the baseband device. For example, a remote radio unit (RRU) is remotely located from the BBU. In addition, the radio frequency device may be remotely located from the DU without being disposed within the DU, or integrated with the DU, or a part of the radio frequency device is remotely located from the DU and the remaining part is integrated with the DU. This is not limited in this specification.

[0106] It should be understood that the number and types of UEs included in the communication system shown in FIGS. 2 and 3b are merely examples, and the embodiments of this application are not limited thereto. For example, more UEs communicating with an access network device (e.g., gNB) may be included. For the sake of brevity, details are not described in the accompanying drawings. Additionally, in the communication system shown in FIG. 2, one base station and one UE connected to each DU are shown, but the communication system may not be limited to including a base station and a UE connected to each DU. Details are not repeated here.

[0107] It should be understood that FIGS. 1 to 3b only show some functions or devices in the embodiments of this application, and the communication system architecture may further include more or fewer functions or devices. For example, the 5GC device in FIG. 1 may further include unified data management (UDM), data network (DN), etc., and the DU shown in FIG. 2 may be further composed of more logical cells, etc.

[0108] Furthermore, as shown in FIG. 4a, compared with the architecture shown in FIG. 3b, the CU of the network device may alternatively be in a form in which the control plane (CP) and the user plane (UP) are separated. In other words, the CU may be divided into two logical network elements, namely CU-CP and CU-UP. Currently, the interface between the CU and the DU in the LTE system is called the W1 interface, and the interface between the CU and the DU in the NR system is called the F1 interface. The functions of the two interfaces are similar. In FIG. 4a, an example in which the network device is the gNB of the NR system is used for the description. The F1 interface includes a control plane (CP) and a user plane (UP). The transport layer protocol of the control plane is the stream control transport protocol (SCTP), and the message transmitted is the F1 application protocol (F1 AP) message. The transport layer protocol of the user plane is the General Packet Radio Service (GPRS) Tunnelling Protocol User Plane (GTP-U).

[0109] The interface between the CU-CP and the CU-UP is called E1 and is used to transmit signaling between the CU-CP and the CU-UP. The F1-C interface between the CU-CP and the DU is used to transmit F1 signaling between the CU-CP and the DU and the RRC signaling of the terminal device. The F1-U interface between the CU-CP and the DU is used to transmit data radio bearer (DRB) data. After receiving the uplink data carried on the DRB via the air interface of the DU, the DU processes the data in the physical layer, MAC layer, and RLC layer, and then transmits the DRB data to the CU via the F1-U interface. After receiving the RRC message transmitted by the terminal device via the air interface, the DU processes the message in the physical layer, MAC layer, and RLC layer of the DU, and then transmits the RRC message to the CU via the F1-CP interface.

[0110] For example, the functions of the CU may be implemented by one entity or different entities. For example, as shown in FIG. 2, the functions of the CU may be further divided. Specifically, the control plane and the user plane are divided and implemented using different entities, namely, a control plane CU entity (i.e., a CU-CP entity) and a user plane CU entity (i.e., a CU-UP entity). The CU-CP entity and the CU-UP entity may be coupled to the DU to jointly complete the functions of the access network device. The interface between the CU-CP entity and the CU-UP entity may be the E1 interface, the interface between the CU-CP entity and the DU may be the F1-C interface, and the interface between the CU-UP entity and the DU may be the F1-U interface. One DU and one CU-UP may be connected to one CU-CP. Under the control of the same CU-CP, one DU may be connected to multiple CU-UPs, and one CU-UP may be connected to multiple DUs.

[0111] The network architectures and service scenarios described in the embodiments of this application are intended to more clearly describe the technical solutions of the embodiments of this application, and it should be noted that they do not constitute a limitation to the technical solutions provided in the embodiments of this application. Those skilled in the art will understand that with the evolution of network architectures and the emergence of new service scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0112] As described above, when the CU-DU architecture is used in a network device, the CU includes the RRC layer and plays a role in managing the RRC state of the terminal device. In a 5G network, three RRC states, namely, the RRC idle state, the RRC Inactive state, and the RRC connected state, may be included.

[0113] In the RRC connected state, there is a dedicated RRC connection between the terminal device and the access network device. The dedicated RRC connection is a DRB or SRB1 connection. In the RRC idle state, there is no dedicated RRC connection between the terminal device and the access network device.

[0114] The RRC inactive state is a new RRC state in 5G. Since a UE in the RRC inactive state can be quickly switched to the RRC connected state by the RRC Resume procedure without re-access, the UE in the RRC inactive state can have a low data transmission recovery delay. The terminal device stores the context of the terminal device, and the source network device (Last serving gNB) stores the context of the terminal device as well as the NG connection to the AMF and UPF. The dedicated RRC connection between the terminal device and the access network device can be interrupted and then resumed. In the RRC inactive state, the terminal device does not need to notify the access network device when moving within the RNA. When moving within the same RNA, the UE does not need to exchange information with the gNodeB. When moving out of the RNA, the UE needs to initiate the RNA update process.

[0115] In addition, the UE in the RRC inactive state interrupts data processing, and the UE in the RRC inactive state may obtain a power consumption level close to that of the RRC idle state in order to reduce the power consumption of the terminal device. Similar to the RRC idle state, only the content (Paging and broadcast) in the common search space can be received, cell reselection can be performed in the RRC inactive state, and the principle of cell reselection in the RRC inactive state is the same as that in the RRC idle state.

[0116] In the RRC inactive state, the terminal device may change from the RRC inactive state to the RRC connected state by requesting the resumption of the RRC connection. Figure 4b is a schematic flowchart of an RRC connection resumption method according to an embodiment of the present application. The steps of the method include the following steps.

[0117] Step 401: The terminal device sends an RRC resume request to the target base station.

[0118] After exiting the coverage of the source base station and entering the coverage of the target base station gNB, the terminal device may initiate the RRC resume procedure to the target base station. The RRC resume request may carry the I-RNTI so that the target base station can request the context of the terminal device from the source base station.

[0119] Step 402: The target base station sends a retrieve UE context request to the source base station.

[0120] The retrieve UE context request includes the I-RNTI in the RRC resume request sent by the terminal. The source base station may determine the context of the terminal device based on the I-RNTI and the stored context of the terminal device.

[0121] Step 403: The source base station sends a retrieve UE context response to the target base station.

[0122] The retrieve UE context response may include the context of the terminal device.

[0123] Step 404: The target base station sends an RRC resume message to the terminal device.

[0124] Correspondingly, after receiving the RRC resume message, the terminal device enters the RRC connected state to resume the RRC connection.

[0125] Step 405: The terminal device sends an RRC Resume complete message to the target base station.

[0126] Step 406: The target base station sends Xn-U address indication to the source base station.

[0127] The data transfer address indication information may indicate a tunnel address for data transfer of the source base station. For example, the data transfer address may be a tunnel address used to transfer downlink data. In this case, the source base station may have the downlink data of the terminal device, may send the downlink data to the target base station, and then the target base station may send the downlink data to the terminal device.

[0128] Step 407: The source base station sends a path switch request to the core network.

[0129] The path switch request may be used to switch the data transfer path between the core network and the base station. For example, the connection between the UPF and the source base station may be switched to the connection between the UPF and the target base station, and subsequent downlink data may be directly sent to the target base station using the UPF.

[0130] Step 408: The core network device sends a path switch response to the source base station.

[0131] Step 409: The core network device sends a context release message to the source base station to indicate to the source base station to release the context of the terminal device.

[0132] The signaling procedures for switching from the RRC idle state to the RRC connected state, i.e., compared with the initial access procedures of the UE, include random access procedures, RRC connection setup procedures, and initial context setup procedures. The signaling procedures from the RRC inactive state to the RRC connected state can reduce a large amount of signaling interactions (for example, RRC reconfiguration and security mode configuration procedures are reduced on the Uu interface, and context setup and authentication procedures are reduced on the NG interface). The access delay in the RRC inactive state is smaller than that in the RRC idle state, which is obtained by reducing signaling interactions.

[0133] The context setup procedures of the terminal device are specifically described below. For details, please refer to Figure 5.

[0134] Step 501: The terminal device sends the capability information to the CU of the network device.

[0135] The capability information indicates the capabilities of the terminal device. Further, optionally, the capability information indicates that the terminal device has the ability to transmit data in the inactive state, and the capability indicates that the terminal device has the ability to transmit uplink information with a configured grant or a scheduling grant in the inactive state. The uplink information includes, but is not limited to, uplink signaling and uplink data. The uplink signaling may be uplink RRC signaling, etc., and the uplink data may be uplink service data, such as video data or audio data.

[0136] A scheduling grant is a resource allocated to a terminal device by a network device based on a resource request, and it should be noted that the resource request is sent by the terminal device. For example, the resource request may be a preamble in a random access process or an uplink scheduling request. A configured grant is a resource preconfigured by the network device, characterized by one-time allocation and repeated use, and the terminal device does not need to send a resource request.

[0137] It should be noted that the terminal device has multiple capabilities, and the capability information may alternatively indicate another capability of the terminal device. This is not limited in the embodiments of this application.

[0138] Step 502: The CU of the network device sends a UE context setup request message to the DU of the network device.

[0139] The UE context setup request message may be used to request setting the context of the terminal device.

[0140] Optionally, the UE context setup request message may include capability information.

[0141] Step 503: The DU of the network device sets the context of the terminal device and sends a UE context setup response message to the CU of the network device.

[0142] It should be noted that in the embodiments of this application, the context may include an air interface context and an F1 context.

[0143] The air interface context may include the RLC layer configuration, MAC layer configuration, physical layer configuration information, I-RNTI, C-RNTI, etc. of the terminal device. Alternatively, the air interface context may include the "configured grant for data transmission in the inactive state", the configuration information of the PDCCH for transmitting physical layer feedback information, or the RNTI for scrambling the PDCCH. The F1 context may include the F1AP ID, transport layer address information for F1 data transmission, etc. The transmission of the DRB data of the terminal device between the CU of the network device and the DU of the network device may also be referred to as F1 data transmission.

[0144] In the embodiments of the present application, the context set by the DU of the network device for the terminal device may include one or more of the following items.

[0145] 1. Configured grant configured for the terminal device: The configured grant may be used to indicate the uplink resources allocated to the terminal device. The configured grant may include, but is not limited to, one or more of the frequency domain resources, periodicity, start position, and data demodulation reference information of the physical uplink shared channel (PUSCH).

[0146] Optionally, the configured grant may be configured for an inactive terminal device, and the inactive terminal device may use the configured grant to transmit one or both of uplink RRC signaling and uplink data.

[0147] Optionally, the time-frequency resource configured by the configured grant may be a time-frequency resource dedicated to the terminal device, that is, a time-frequency resource not shared with another terminal device. In this case, the DU of the network device may establish a mapping relationship between the configured grant and the context of the terminal device, and a mapping relationship between the configured grant and the data transmission channel of the terminal device.

[0148] Optionally, the time-frequency resource configured by the configured grant may be a time-frequency resource shared by the terminal device and another terminal device. In this case, when it is determined that the terminal device enters the inactive state, the CU of the network device may send the inactive I-RNTI to the DU of the network device. The DU of the network device may set a mapping relationship between the configured grant and the I-RNTI of the terminal device. The I-RNTI may be a unique identity of the terminal device in the inactive state in the radio access network (RAN)-based notification area (RNA).

[0149] 2. Configuration information of PDCCH configured for the terminal device: The configuration information of PDCCH may be used for transmitting feedback information of uplink data, or for scheduling PUSCH transmission, and for scheduling physical downlink shared control channel (PDSCH) transmission, etc.

[0150] The configuration information of PDCCH includes, but is not limited to, resource position information, periodicity, start position, etc. of PDCCH.

[0151] In an embodiment of the present application, the PDCCH may schedule the transmission of at least one of physical layer signaling, such as acknowledgement (ACK) or negative acknowledgement (NACK) signaling, uplink grants for initial transmission, and uplink grants for retransmission. The PDCCH may further schedule the transmission of the PDSCH, and the information carried by the PDSCH includes, but is not limited to, one or more of downlink RRC signaling, downlink data, and timing advance commands. The terminal device may perform uplink transmission and downlink transmission based on the scheduling of the PDCCH.

[0152] 3. Temporary identifier for scrambling the PDCCH: The temporary identifier is a 32-bit radio network temporary identity (RNTI) for scrambling the PDCCH. For example, the temporary identifier may be a cell radio network temporary identity (C-RNTI) of the terminal device.

[0153] 4. Configuration information of the RLC layer corresponding to the radio bearer configured for the terminal device.

[0154] 5. Configuration information of the MAC layer configured for the terminal device.

[0155] 6. I-RNTI configured for the terminal device.

[0156] It should be noted that the above are merely examples, and the context of the terminal device may further include other information. This is not limited in the embodiments of the present application, and the examples are not described one by one in this specification.

[0157] For example, the UE context setup response message transmitted by the CU of the network device may include the context of the terminal device.

[0158] In the procedure shown in FIG. 5, only the main steps are described. There may be other steps in the process of setting the context for the terminal device, which are not described in detail here.

[0159] The context of the terminal device is set in the procedure shown in FIG. 5.

[0160] In the RRC inactive state, small data is transmitted and there is no need to enter the RRC connected state. This can avoid cases where the UE needs to enter the RRC connected state when transmitting data. In a special scenario, for example, when the UE transmits small data, the data transmission volume is not large, but the data may need to be transmitted continuously multiple times. As a result, the UE needs to frequently switch between the RRC inactive state and the RRC connected state, and signaling is frequently transmitted. Therefore, in one possible implementation form, the terminal device does not need to enter the RRC connected state when transmitting small data in the RRC inactive state. This can reduce the signaling overhead. The terminal in the RRC inactive state can transmit small data in the RA-SDT manner. In the CU-DU split scenario shown in FIG. 1, since the base station is split into two parts, CU and DU, after the terminal exits the coverage of the source base station and enters the coverage of the target base station, how the DU of the network device determines whether to reserve the context of the terminal device needs to be considered in the RRC inactive state.

[0161] As shown in FIG. 6, in one embodiment of the present application, a communication method is provided. The method includes the following steps.

[0162] Step 601: The CU of the first network device sends an RRC Release message to the DU of the first network device.

[0163] The first network device can be a source network device accessed by a terminal device in the RRC connected state. The CU of the first network device determines an RRC Release message to be sent to the DU of the first network device when the terminal device switches from the RRC connected state to the RRC inactive state. The RRC Release carries a suspend configuration, and the configuration indicates the terminal device to switch to the RRC inactive state. Optionally, the CU of the first network device sends indication information for storing the context of the DU of the first network device to the DU of the first network device.

[0164] Step 602: After receiving the RRC Release message, the DU of the first network device stores the context of the terminal device.

[0165] For example, the context may be stored by the first network device after the first network device receives indication information for storing the context of the DU, or may be the context stored by default by the DU of the first network device. For details, refer to the method of setting the context of the DU in FIG. 5. For example, the context of the DU of the first network device may include at least one of the following.

[0166] 1. Small Data Transmission Configured Grant (SDT-CG) Configuration: The Small Data Configured Grant (CG) Configuration may include at least one of indication information of CG time domain resources, indication information of CG frequency domain resources, etc.

[0167] 2. Small Data Transmission SDT - Time Alignment (TA) Configuration: Time Alignment Timer for Small Data Transmission SDT - (TA timer, TAT).

[0168] 3. SDT - RLC Configuration. The configuration may include at least one of SDT - RLC mode (AM or UM) indication information, RLC sequence number (SN) length indication information, etc.

[0169] Step 603: The DU of the first network device sends an RRC connection release (RRC Release) message to the terminal device.

[0170] Step 604: The terminal device is switched from the RRC connected state to the RRC inactive state.

[0171] Step 605: When transmitting data, the terminal device triggers the small data transmission process. For a specific small data transmission process, refer to the transmission mode of the prior art. Details are not repeated here.

[0172] Step 606: The terminal device sends an RRC resume request message and uplink data to the second network device. The uplink data may be carried in NAS information (NAS message).

[0173] For example, the first network device is a source network device, and the second network device is a target network device. In some scenarios, after the terminal device exits the coverage of the DU of the source network device and enters the coverage of the DU of the target network device, the terminal device may initiate an RRC resume procedure to the DU of the target network device. In this case, the DU of the source network device needs to be handed over to the DU of the target network device. The RRC resume request may carry the I-RNTI, and as a result, the CU of the target network device may request the context of the terminal device from the CU of the source network device.

[0174] In some other scenarios, after the terminal device exits the coverage of the CU of the source network device and enters the coverage of the CU of the target network device and the coverage of the DU of the target network device, the terminal device may initiate an RRC resume procedure to the CU of the target network device or the DU of the target network device. In this case, the CU of the source network device needs to be handed over to the CU of the target network device, and the DU of the source network device needs to be handed over to the DU of the target network device. The RRC resume request may carry the I-RNTI, and as a result, the CU of the target network device may request the context of the terminal device from the CU of the source network device. In this way, the DU of the target network device may obtain the context of the terminal using the CU of the target network device.

[0175] Step 607: The second network device sends a Retrieve UE context request to the CU of the first network device.

[0176] In a possible implementation form, the UE context search request may include the identity verification information of the terminal device, and the CU of the first network device executes identity verification by referring to the security context in the CU of the first network device and the verification information in the UE context search request.

[0177] Step 608: The CU of the first network device sends a Retrieve UE context response to the target network device.

[0178] In some embodiments, the CU of the first network device may send a UE context search response to the target network device after the identity verification of the CU of the first network device is successful.

[0179] In a possible implementation form, the Anchor relocation method is used as an example. The UE context search response may include all contexts. For example, the UE context search response may include SDAP configuration, RLC configuration, PDCP configuration, RB configuration, etc.

[0180] In a possible implementation form, the No Anchor relocation method is used as an example. The UE context search response may include a part of the context of the terminal device. For example, the UE context search response may include the RLC configuration.

[0181] Step 609: The CU of the first network device sends a first message to the DU of the first network device.

[0182] The first message indicates to the DU of the first network device to release the context of the terminal device.

[0183] In some embodiments, the CU of the first network device may send release indication information to the DU of the first network device after the identity verification is successful. Of course, the CU of the first network device may alternatively send release indication information to the DU of the first network device after determining that an RRC connection is established between the DU of the target network device and the terminal device.

[0184] Step 6010: The DU of the first network device releases the context of the DU of the terminal device.

[0185] The DU of the first network device may release the context of the DU of the terminal device after receiving the indication information.

[0186] According to the foregoing method, after determining that the terminal device starts a resume process on a new base station, the CU of the source network device may determine that the terminal device will not return to the coverage of the DU of the source network device. Therefore, the CU of the source network device may send context release indication information to the DU of the source network device so that the DU can allocate resources to another terminal, thereby improving the DU resource utilization rate.

[0187] In connection with the network architecture of FIG. 1, in a small data transmission scenario in the RRC inactive state, an embodiment of the present application further provides a communication method. As shown in FIG. 7, the method includes the following steps.

[0188] Step 701: The terminal device sends a configured grant request to the first network device.

[0189] A configured grant request may request a first network device to configure a configured grant small data transmission resource of a terminal device. For example, the configured grant request may request a TBS configuration to configure the resource periodically. The resource may be transmitted to the first network device when the terminal device sets up an RRC connection.

[0190] Note that step 701 is optional, and the first network device may further configure the CG-SDT resource for the terminal in another way.

[0191] Step 702: The terminal device determines at least one SSB.

[0192] In some embodiments, the terminal device may determine at least one SSB.

[0193] For example, the terminal device may determine SSB1, and SSB1 is associated with the CG-SDT resource. The terminal device may further determine SSB2, and SSB2 has no association relationship with the CG-SDT resource.

[0194] Therefore, after the first network device configures the CG-SDT resource for the terminal device, the terminal may determine whether it can use the CG-SDT resource to transmit small data based on the determined SSB associated with the CG-SDT resource. In this way, it is avoided that the terminal device needs to separately indicate to the terminal device the CG-SDT resource to be used when the terminal device can use the CG-SDT resource to transmit small data.

[0195] Step 703: The first network device transmits uplink synchronization indication information to the terminal device.

[0196] Correspondingly, the terminal device adjusts uplink synchronization based on the uplink synchronization indication information.

[0197] Step 704: The CU of the first network device transmits the first instruction information to the terminal device using the DU of the first network device.

[0198] The first instruction information indicates the first resource of the configured grant of the terminal device, and the first resource is associated with the first SSB. The first SSB is used by the terminal device to determine whether to transmit data using the first resource in the inactive state. In some embodiments, the first instruction information may be carried in an RRC release message. Correspondingly, after receiving the first instruction information, the terminal device may determine that the configured grant resource used to transmit small data is the first resource.

[0199] After obtaining the first instruction information, the terminal device may enter the RRC inactive state to reduce power consumption.

[0200] Step 705: The terminal determines that the first SSB is the reference SSB of the first resource based on the association relationship between the first resource and the SSB and the CG-SDT resource.

[0201] The reference SSB of the first resource is used to determine whether the uplink synchronization of the first resource is valid. For example, when it is determined that the uplink synchronization of the first resource is valid, it is determined to transmit data using the first resource, or when it is determined that the uplink synchronization of the first resource is invalid, it is determined to release the first resource.

[0202] In some embodiments, when the RSRP of the first SSB is greater than or equal to the first threshold, it is determined that the uplink synchronization of the first resource is valid.

[0203] For example, when the RSRP of the first SSB is greater than or equal to the first threshold, the first SSB is determined as the reference SSB of the first resource. It should be noted that even if the RSRP of SSB2 is greater than or equal to the first threshold, SSB2 is considered not to be the SSB associated with the first resource, and SSB2 cannot be used as the reference SSB of the first resource.

[0204] Step 706: The terminal device determines whether uplink synchronization of the first resource is effective based on the reference SSB. If the uplink synchronization of the first resource is effective, step 707 is executed; or if the uplink synchronization of the first resource is ineffective, step 708 is executed.

[0205] In some embodiments, the terminal device may determine that the uplink synchronization of the first resource is ineffective when the increase variation of the RSRP of the first SSB is greater than or equal to the second threshold, or when the decrease variation of the RSRP of the first SSB is greater than or equal to the third threshold. For example, the second threshold or the third threshold is configured by the network device and sent to the terminal device in the RRC release message.

[0206] Step 707: The terminal device does not transmit (or send) data to the first network device using the first resource.

[0207] Optionally, after determining that the TA is ineffective, the terminal device may release the first resource.

[0208] Step 708: The terminal device executes a small data transmission process. Specifically, the terminal device transmits (or sends) data to the first network device using the first resource.

[0209] For example, the data transmitted by the terminal device to the first network device using the first resource may be user data or service data, etc. This is not limited in this specification.

[0210] Step 709: When it is determined that the terminal device is handed over to the second network device, the terminal device sends a resume request message to the second network device.

[0211] Step 7010: The second network device sends an RRC resume message to the terminal device.

[0212] Optionally, the RRC resume message includes second indication information. The second indication information indicates a second resource of the configured grant of the terminal device, and the second resource is used by the terminal device to transmit data using the second resources in the inactive state and the connected state. In other words, the second resource may be used in the RRC connected state of the terminal device.

[0213] Correspondingly, the terminal device receives the RRC resume message sent by the network device. In some embodiments, the second resource may be the same as the first resource. In this case, after receiving the RRC resume message, the terminal device enters the RRC connected state and transmits second data to the second network device using the second resource. Alternatively, the second resource may be different from the first resource. In this case, the terminal device may determine whether the uplink synchronization of the second resource is valid based on a method of determining whether the uplink synchronization of the first resource is valid. When it is determined that the uplink synchronization of the second resource is valid, the terminal device may transmit data to the second network device using the second resource.

[0214] Optionally, Step 7011: The CU of the first network device sends a first message to the DU of the first network device.

[0215] Before transmitting the first message to the DU of the first network device, the CU of the first network device may further execute steps 607 and 608. Details are not repeated here.

[0216] Step 7012: The DU of the first network device releases the context of the DU of the terminal device.

[0217] In relation to the network architecture of FIG. 1 and the implementation form of FIG. 6, after the terminal device is handed over to the second network device, the terminal device enters the RRC connected state, and the terminal device may enter the RRC inactive state again. In a small data transmission scenario where the terminal device is switched from the RRC connected state to the RRC inactive state, an embodiment of the present application further provides a communication method. As shown in FIG. 8, the method includes the following steps.

[0218] Step 801: The terminal device transmits a configured grant request to the second network device.

[0219] The configured grant request may request the second network device to determine configured grant small data transmission resources, and the resources may be used by the terminal device to transmit small data in the RRC connected state.

[0220] In some embodiments, the configured grant request transmitted by the terminal device to the second network device may further request the second network device to determine a second resource. The second resource is used by the terminal device to transmit data using the second resources in the inactive state and the connected state. Optionally, the second resource is associated with a second SSB, and the second SSB is used by the terminal device to determine whether to transmit data using the second resource in the inactive state and the RRC connected state.

[0221] In some other embodiments, the terminal device may further request in advance the configured grant small data transmission resources in the RRC inactive state. For details, refer to the aforementioned method by which the terminal device obtains the first resource. Details are not repeated here.

[0222] It should be noted that the first resource may be the same as or different from the second resource. This is not limited in this specification. In addition, step 801 is optional, and the second network device may further configure the CG-SDT resources for the terminal in another way.

[0223] Step 802: The terminal device determines at least one SSB.

[0224] In some embodiments, the terminal device may determine at least one SSB.

[0225] For example, the terminal device may determine SSB1 and SSB3, where SSB1 is associated with the first resource and SSB3 is associated with the second resource. The terminal device may further determine SSB2, and SSB2 has no association relationship with the CG-SDT resource.

[0226] Therefore, after the first network device configures the CG-SDT resource for the terminal device, the terminal may determine whether it can use the CG-SDT resource to transmit small data based on the determined SSB associated with the CG-SDT resource. In this way, it is avoided that when the terminal device can use the CG-SDT resource to transmit small data, it is necessary to separately indicate to the terminal device the CG-SDT resource to be used.

[0227] Step 803: The second network device transmits uplink synchronization indication information to the terminal device.

[0228] Correspondingly, the terminal device adjusts the TA based on the uplink synchronization indication information.

[0229] Step 804: The CU of the second network device uses the DU of the second network device to send the first indication information to the terminal device.

[0230] The first indication information indicates the first resource of the configured grant of the terminal device, and the first resource is associated with the first SSB. The first SSB is used by the terminal device to determine whether to transmit data using the first resource in the non-active state. Correspondingly, after receiving the first indication information, the terminal device may determine that the configured grant resource used to transmit small data is the first resource.

[0231] Optionally, the CU of the second network device uses the DU of the second network device to send the second indication information to the terminal device.

[0232] The second indication information indicates the second resource of the configured grant of the terminal device. The second resource is associated with the second SSB, and the second SSB is used by the terminal device to determine whether to transmit data using the second resource in the connected state. Alternatively, the second SSB is used by the terminal device to determine whether to transmit data using the second resource in the connected state and the non-active state.

[0233] Step 805: The terminal device determines that the second SSB is the reference SSB of the second resource based on the association relationship between the second resource and SSB and the CG-SDT resource.

[0234] The reference SSB of the second resource is used to determine whether the uplink synchronization of the second resource is valid. For example, when it is determined that the uplink synchronization of the second resource is valid, it is determined to transmit data using the second resource, or when it is determined that the uplink synchronization of the second resource is invalid, it is determined to release the second resource.

[0235] In some embodiments, when the RSRP of the second SSB is greater than or equal to the first threshold, it is determined that the uplink synchronization of the second resource is valid.

[0236] For example, when the RSRP of the second SSB is greater than or equal to the first threshold, the second SSB is determined as the reference SSB of the second resource. It should be noted that even if the RSRP of SSB2 is greater than or equal to the first threshold, SSB2 is not regarded as the SSB associated with the second resource and cannot be used as the reference SSB of the second resource.

[0237] Optionally, the terminal device may determine that the first SSB is the reference SSB of the first resource based on the association relationship between the first resource and the SSB and the CG-SDT resource.

[0238] The reference SSB of the first resource is used to determine whether the uplink synchronization of the first resource is valid. For example, when it is determined that the uplink synchronization of the first resource is valid, it is determined to transmit data using the first resource, or when it is determined that the uplink synchronization of the first resource is invalid, it is determined to release the first resource.

[0239] In some embodiments, when the RSRP of the first SSB is greater than or equal to the first threshold, it is determined that the uplink synchronization of the first resource is valid.

[0240] For example, when the RSRP of the first SSB is greater than or equal to the first threshold, the first SSB is determined as the reference SSB. Note that even if the RSRP of the second SSB is greater than or equal to the first threshold, the second SSB is considered not to be the SSB associated with the first resource, and the second SSB cannot be used as the reference SSB for the first resource.

[0241] Step 806: The terminal device determines whether uplink synchronization of the second resource is valid based on the reference SSB of the second resource. If the uplink synchronization of the second resource is valid, step 808 is executed, or if the uplink synchronization of the second resource is invalid, step 807 is executed.

[0242] In some embodiments, the terminal device may determine that the uplink synchronization of the second resource is invalid when the increase variation of the RSRP of the second SSB is greater than or equal to the second threshold, or when the decrease variation of the RSRP of the second SSB is greater than or equal to the third threshold. For example, the second threshold or the third threshold is configured by the network device and sent to the terminal device in the RRC release message.

[0243] Step 807: The terminal device does not transmit data to the second network device using the second resource.

[0244] Optionally, the terminal device may determine that the TA is invalid, and the terminal device may release the second resource.

[0245] Step 808: The terminal device executes a small data transmission process. Specifically, the terminal device transmits user data to the second network device using the second resource.

[0246] Step 809: After determining to enter the RRC inactive state, the terminal device determines whether uplink synchronization of the first resource is valid based on the reference SSB of the first resource. If the uplink synchronization of the first resource is valid, step 8011 is executed, or if the uplink synchronization of the first resource is invalid, step 8010 is executed.

[0247] For the method by which the terminal device determines to enter the RRC inactive state, refer to steps 401 to 404. Details are not repeated here.

[0248] In some embodiments, the terminal device may determine that the uplink synchronization of the first resource is invalid when the increase variation of the RSRP of the first SSB is greater than or equal to a second threshold, or when the decrease variation of the RSRP of the first SSB is greater than or equal to a third threshold. For example, the second threshold or the third threshold is configured by the network device and sent to the terminal device in an RRC release message.

[0249] Step 8010: The terminal device does not transmit data to the second network device using the first resource.

[0250] Optionally, the terminal device determines that the TA is invalid, and the terminal device may release the second resource.

[0251] Step 8011: The terminal device executes a small data transmission process. Specifically, the terminal device transmits user data to the second network device using the first resource.

[0252] Based on the condition that TA is determined to be valid, the SSB associated with the configured grant resource is used as the reference SSB. As a result, the terminal device learns whether TA is valid and determines whether it can use the configured grant resource indicated by the network device. In addition, in the process of starting small data transmission for the configured grant, the configured grant request initiated by the terminal may further request to configure the CG-SDT resources used in the RRC connected state. As a result, when the terminal device is in the inactive state and the terminal device is switched to the RRC connected state, the terminal device may continue to use the configured CG-SDT resources. Therefore, there is no need to reconfigure the CG-SDT resources after the switch, small data transmission can be performed more efficiently, and small data can be transmitted smoothly whether during or after the switch.

[0253] Figure 9 is a schematic diagram of a communication device according to an embodiment of the present application. The device is configured to perform the steps executed by the corresponding first network device in the embodiment of the foregoing method. As shown in Figure 9, device 900 includes a central unit 901 and a distributed unit 902. The central unit 901 may include a processing module 9010. Optionally, the central unit 901 further includes a transmission module 9020 and a reception module 9030.

[0254] In some embodiments, the processing module 9010 is configured to use the transmission module 9020 to transmit first indication information to the terminal device via the distributed unit 902 of the first network device. The first indication information indicates the first resource of the configured grant of the terminal device, and the first resource is associated with the first SSB. The first SSB is used by the terminal device to determine whether to transmit data using the first resource in the inactive state.

[0255] In a possible implementation form, the processing module 9010 is configured to use the sending module 9020 to send the context of the terminal device in the inactive state to the second network device. The processing module 9010 is configured to use the sending module 9020 to send a first message to the distributed unit 902 of the first network device. The first message indicates to the distributed unit 902 of the first network device to release the context of the terminal device.

[0256] In a possible implementation form, before the processing module 9010 is configured to use the sending module 9020 to send the context of the terminal device in the inactive state to the second network device, the processing module 9010 is further configured to use the receiving module 9030 to receive a context search request of the terminal device from the second network device.

[0257] In a possible implementation form, before the processing module 9010 is configured to use the sending module 9020 to send the context of the terminal device in the inactive state to the second network device, the processing module 9010 is further configured to normally verify the identity of the second network device.

[0258] In a possible implementation form, the processing module 9010 is configured to use the sending module 9020 to send second instruction information to the terminal device via the distributed unit of the first network device. The second instruction information indicates the second resource of the configured grant of the terminal device, and the second resource is used by the terminal device to send data using the second resources in the inactive state and the connected state.

[0259] In some other embodiments, the processing module 9010 of the central unit is configured to use the transmission module 9020 of the central unit to transmit the context of the terminal device in the inactive state to a second network device. The processing module 9010 of the central unit is configured to use the transmission module 9020 of the central unit to transmit a first message to the distributed unit of the first network device. The first message indicates to the distributed unit 902 of the first network device to release the context of the terminal device.

[0260] In one possible implementation, before the processing module 9010 of the central unit is configured to use the transmission module 9020 of the central unit to transmit the context of the terminal device in the inactive state to a second network device, the receiving module 9030 of the central unit is further configured to receive a context search request of the terminal device from the second network device.

[0261] In one possible implementation, before the processing module 9010 of the central unit is configured to use the transmission module 9020 of the central unit to transmit the context of the terminal device in the inactive state to a second network device, the processing module of the central unit is further configured to successfully verify the identity of the second network device.

[0262] In one possible implementation, the context includes one or more of a configured grant configured for the terminal device, configuration information of a physical downlink control channel configured for the terminal device, a temporary identifier for scrambling the physical downlink control channel, an inactive radio network temporary identifier configured for the terminal device, and configuration information of a radio link control layer corresponding to a radio bearer configured for the terminal device.

[0263] In one possible implementation, the terminal device in the inactive state is configured to transmit data to the communication device 900.

[0264] FIG. 10 is a schematic diagram of a communication device according to an embodiment of the present application. The device is configured to perform the steps executed by the corresponding second network device or terminal device in the embodiment of the foregoing method. As shown in FIG. 10, the device 1000 includes a processing module 1010. Optionally, the device 1000 further includes a transmission module 1020 and a reception module 1030.

[0265] In some embodiments, an example where the communication device in FIG. 10 is a second network device is used. The processing module 1010 is configured to transmit first indication information to the terminal device using the transmission module 1020. The first indication information indicates a first resource of the configured grant of the terminal device, and the first resource is associated with a first SSB. The first SSB is used by the terminal device to determine whether to transmit data using the first resource in the inactive state.

[0266] In relation to the embodiments of FIGS. 9 and 10, in one possible implementation, the RSRP of the first SSB is used to determine whether the uplink synchronization of the first resource is invalid. When it is determined that the uplink synchronization of the first resource is valid, it is determined to transmit data using the first resource, or when it is determined that the uplink synchronization of the first resource is invalid, it is determined to release the first resource.

[0267] In relation to the embodiments of FIGS. 9 and 10, in one possible implementation, when the RSRP of the first SSB is greater than or equal to a first threshold, it is determined that the uplink synchronization of the first resource is valid. When the increase variation of the RSRP of the first SSB is greater than or equal to a second threshold, or when the decrease variation of the RSRP of the first SSB is greater than or equal to a third threshold, it is determined that the uplink synchronization of the first resource is invalid.

[0268] In one possible implementation, in relation to the embodiments of FIGS. 9 and 10, the context includes one or more of a configured grant configured for a terminal device, configuration information of a PDCCH configured for the terminal device, a temporary identifier for scrambling the PDCCH, an I-RNTI configured for the terminal device, and configuration information of an RLC layer corresponding to a radio bearer configured for the terminal device.

[0269] In some other embodiments, an example where the communication device in FIG. 10 is a terminal device is used.

[0270] In one possible implementation, the processing module 1010 is configured to receive first indication information transmitted by a central unit of the first network device by using the receiving module 1030 via a distributed unit of the first network device. The first indication information indicates a first resource of a configured grant of the terminal device, and the first resource is associated with a first SSB. The processing module 1010 is configured to determine whether to transmit data by using the first resource in a non-active state based on the first SSB.

[0271] In one possible implementation, the processing module 1010 is configured to receive first indication information transmitted by a second network device by using the receiving module 1030. The first indication information indicates a first resource of a configured grant of the terminal device, and the first resource is associated with a first SSB. The terminal device determines whether to transmit data by using the first resource in a non-active state based on the first SSB. It should be noted that the second network device may be a network device to which the terminal device is handed over from the first network device, or may be a network device before the terminal device is handed over from the first network device.

[0272] In a possible implementation form, the processing module 1010 determines, based on the reference signal received power RSRP of the first SSB, whether the uplink synchronization of the first resource is invalid in the non-active state. When it is determined that the uplink synchronization of the first resource is valid, the processing module 1010 determines to transmit data using the first resource, or when it is determined that the uplink synchronization of the first resource is invalid, the processing module 1010 determines not to transmit data using the first resource, and is configured accordingly.

[0273] In a possible implementation form, in the non-active state, when it is determined that the uplink synchronization of the first resource is invalid, the processing module 1010 is configured to release the first resource.

[0274] In a possible implementation form, the processing module 1010 is configured to determine, based on the RSRP of the first SSB, whether the uplink synchronization of the first resource is invalid in the non-active state, which includes that when the RSRP of the first SSB is greater than or equal to the first threshold, the processing module 1010 determines that the uplink synchronization of the first resource is valid. When the increase variation of the RSRP of the first SSB is greater than or equal to the second threshold, or when the decrease variation of the RSRP of the first SSB is greater than or equal to the third threshold, the processing module 1010 determines that the uplink synchronization of the first resource is invalid.

[0275] In a possible implementation form, the processing module 1010 is configured to receive, via the distributed unit of the first network device, the second indication information transmitted by the central unit of the first network device using the receiving module 1030. The second indication information indicates the second resource of the configured grant of the terminal device, and the second resource of the configured grant is used by the terminal device to transmit data using the second resources in the non-active state and the connected state.

[0276] In a possible implementation form, the processing module 1010 is configured to receive second instruction information transmitted by a second network device by using the receiving module 1030. The second instruction information indicates a second resource of a configured grant of the terminal device, and the second resource is used by the terminal device to transmit data by using the second resources in the inactive state and the connected state.

[0277] In a possible implementation form, the processing module 1010 is configured to be restored to the connected state by using the context of the terminal device acquired by the second network device, and the context of the terminal device is acquired by the second network device receiving it and is from the central unit of the first network device.

[0278] Optionally, the communication device 900 or the communication device 1000 may further include a storage unit. The storage unit is configured to store data or instructions (which may also be referred to as codes or programs). The foregoing units may interact with or be coupled to the storage unit to implement the corresponding method or function. For example, the processing module 9010 or the processing module 1010 may read the data or instructions in the storage unit so that the communication device implements the method of the foregoing embodiments.

[0279] It should be understood that the division of the device into units is only a logical function division. In actual implementation, all or part of the units may be integrated into one physical entity or may be physically separated. In addition, all units in the device may be implemented in the form of software called by a processing element, or may be implemented in the form of hardware, or some units may be implemented in the form of software called by a processing element, and some units may be implemented in the form of hardware. For example, each unit may be a separately arranged processing element or may be integrated into the chip of the device for implementation. In addition, each unit may alternatively be stored in memory in the form of a program to be called by a processing element of the device to perform the function of the unit. In addition, all or part of the units may be integrated or may be implemented independently. The processing element here may be called a processor or may be an integrated circuit having signal processing capabilities. In the implementation process, the steps in the foregoing method or the foregoing units may be implemented by using the integrated logic circuit of the hardware in the processor element or may be implemented in the form of software called by the processing element.

[0280] In one example, the unit in any one of the aforementioned devices may be one or more integrated circuits configured to implement the aforementioned method, such as one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more field programmable gate arrays (FPGAs), or a combination of at least two of these forms of integrated circuits. As another example, when the unit in the device is implemented in a form where a processing element schedules a program, the processing element may be a general-purpose processor, such as a central processing unit (CPU), or another processor capable of calling a program. As yet another example, the unit may be implemented by being integrated in the form of a system-on-a-chip (SOC).

[0281] The aforementioned unit for reception (e.g., the receiving unit) is an interface circuit of the device and is configured to receive a signal from another device. For example, when the device is implemented in the form of a chip, the receiving unit is that of the chip and is an interface circuit configured to receive a signal from another chip or device. The aforementioned unit for transmission (e.g., the transmitting unit) is an interface circuit of the device and is configured to transmit a signal to another device. For example, when the device is implemented in the form of a chip, the transmitting unit is that of the chip and is an interface circuit configured to transmit a signal to another chip or device.

[0282] FIG. 11 is a schematic diagram of the structure of a communication device according to an embodiment of the present application. The communication device is configured to perform operations executed by the first network device in the foregoing embodiment, or a central unit in the first network device, the second network device, or the terminal device. As shown in FIG. 11, for example, the communication device is the first network device, the second network device, or the terminal device. The communication device includes an antenna 1110, a radio frequency device 1120, and a signal processing unit 1130. The antenna 1110 is connected to the radio frequency device 1120. In the downlink direction, the radio frequency device 1120 receives information transmitted by a network device or another terminal device via the antenna 1110, and transmits the information transmitted by the network device or another terminal device to the signal processing unit 1130 for processing. In the uplink direction, the signal processing unit 1130 processes information of the terminal device and transmits the information to the radio frequency device 1120. The radio frequency device 1120 processes the information of the terminal device and then transmits the processed information to a network device or another terminal device via the antenna 1110.

[0283] For example, the communication device is a network device. The communication device includes an antenna 1110, a radio frequency device 1120, and a signal processing unit 1130. The antenna 1110 is connected to the radio frequency device 1120. In the uplink direction, the radio frequency device 1120 receives information transmitted by a terminal device via the antenna 1110, and transmits the information transmitted by the terminal device to the signal processing unit 1130 for processing. In the downlink direction, the signal processing unit 1130 processes information of the network device and transmits the information to the radio frequency device 1120. The radio frequency device 1120 processes the information of the network device and then transmits the processed information to a terminal device or another terminal device via the antenna 1110.

[0284] The signal processing unit 1130 is configured to perform processing on each communication protocol layer of data. The signal processing unit 1130 may be a subsystem of a communication device, and the communication device may further include another subsystem, for example, a central processing subsystem configured to process the operating system and application layer of the communication device, and as another example, a peripheral subsystem configured to implement a connection to another device. The signal processing unit 1130 may be a separately provided chip. Optionally, the aforementioned device may be arranged in the signal processing unit 1130.

[0285] The signal processing unit 1130 includes one or more processing elements 1131, for example, includes a main control CPU and another integrated circuit, and may further include an interface circuit 1133. In addition, the signal processing unit 1130 may further include a storage element 1132. The storage element 1132 is configured to store data and programs. The program for executing the method executed by the communication device in the above manner may be stored in the storage element 1132, or may not be stored in the storage element 1132. For example, it may be stored in an external memory of the signal processing unit 1130 and loaded into the cache by the signal processing unit 1130 for use. The interface circuit 1133 is configured to communicate with the device. The aforementioned device may be arranged in the signal processing unit 1130. The signal processing unit 1130 may be implemented using a chip. The chip includes at least one processing element and an interface circuit. The processing element is configured to execute any one step of the aforementioned method executed by the communication device. The interface circuit is configured to communicate with other devices. In one implementation form, the unit for implementing the steps of the aforementioned method may be implemented in a form of scheduling a program by the processing element. For example, the device includes a processing element and a storage element. The processing element calls a program stored in the storage element in order to execute the method executed by the communication device in the embodiment of the aforementioned method. The storage element may be a storage element arranged on the same chip as the processing element, that is, an on-chip storage element.

[0286] In another implementation form, the program used to execute the method executed by the communication device by the foregoing method may be in a storage element arranged on a chip different from the processing element, that is, an off-chip storage element. In this case, the processing element calls the program from the off-chip storage element or loads the program into the on-chip storage element in order to call and execute the method executed by the communication device (the first network device, the second network device, or the terminal device) in the foregoing method embodiments.

[0287] In yet another implementation form, the unit of the communication device that implements the steps of the foregoing method may be configured as one or more processing elements. The processing element is arranged in the signal processing unit 1130. The processing element here may be an integrated circuit, for example, one or more ASICs, one or more DSPs, one or more FPGAs, or a combination of these types of integrated circuits. These integrated circuits may be integrated together to form a chip.

[0288] The units for implementing the steps in the foregoing method may be integrated together and implemented in the form of a system-on-a-chip (SOC). The SOC chip is configured to implement the foregoing method. At least one processing element and a storage element may be integrated into the chip, and the processing element calls the program stored in the storage element to implement the foregoing method executed by the communication device. Alternatively, at least one integrated circuit may be incorporated into the chip to implement the foregoing method executed by the communication device. Or, in relation to the foregoing implementation forms, the functions of some units may be implemented by calling a program by the processing element, and the functions of some units may be implemented by the integrated circuit.

[0289] It can be seen that the foregoing apparatus may include at least one processing element and an interface circuit. The at least one processing element is configured to execute any method implemented by the communication device provided in the foregoing method embodiments. The processing element may execute some or all of the steps implemented by the communication device in a first manner, i.e., by calling a program stored in a storage element, or in a second manner, i.e., by combining instructions and the hardware integrated logic circuit within the processing element. Of course, some or all of the steps implemented by the communication device may alternatively be implemented by combining the first manner and the second manner.

[0290] As described above, the processing element here may be a general-purpose processor, such as a CPU, or one or more integrated circuits configured to implement the foregoing method, such as one or more ASICs, one or more microprocessors DSPs, one or more FPGAs, or a combination of at least two of these integrated circuits. The storage element may be one memory or a general term for a plurality of storage elements.

[0291] It should be understood that the memory of the embodiments of the present application may be volatile memory, non-volatile memory, or may include both volatile memory and non-volatile memory. The non-volatile memory may be a read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), or flash memory. The volatile memory may be a random access memory (RAM) used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct rambus RAM (DR RAM). Note that the memory of the systems and methods described herein includes, but is not limited to, these memories and any other suitable type of memory.

[0292] One embodiment of the present application further provides a computer-readable storage medium. The computer-readable storage medium stores a computer program. When the computer program is executed by a computer, any one of the foregoing method embodiments applicable to the first network device, the second network device, or the terminal device is implemented.

[0293] One embodiment of the present application further provides a computer program product. When the computer program product is executed by a computer, any one of the foregoing method embodiments applicable to the first network device, the second network device, or the terminal device is implemented.

[0294] It should be noted that terms such as "first" and "second", for example, "first instruction information and second instruction information", are used only for the purpose of distinction for explanation and should not be construed as indicating or implying relative importance or indicating or implying an order. "At least one" means one or more, and "a plurality of" means two or more. "And / or" is an associative relationship for describing associated objects and represents that three relationships can exist. For example, A and / or B may represent the following cases, that is, the case where only A exists, the case where both A and B exist, and the case where only B exists. In that case, A and B may be in singular or plural form. The character " / " generally indicates an "or" relationship between associated objects. In addition, "at least one of the following items (parts)" or a similar expression indicates any combination of these items, including any combination of a single item (part) or a plurality of items (parts). For example, at least one item (part) of a, b, or c can represent a, b, c, a and b, a and c, b and c, or a, b, and c, and a, b, and c may be singular or plural.

[0295] All or part of the above-described 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 form of a computer program product. The computer program product includes one or more computer programs. When the computer program is loaded and executed on a computer, all or part of the procedures or functions according to the embodiments of the present application are generated. The computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable devices. The computer program may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer program 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, and microwave) manner. The computer-readable storage medium may be any usable medium accessible by a computer or a data storage device such as a server or a data center integrating one or more usable media. The usable media may be magnetic media (e.g., floppy disk, hard disk, magnetic tape), optical media (e.g., digital video disc (DVD)), semiconductor media (e.g., solid-state drive (SSD)), etc.

[0296] An embodiment of the present application further provides a processing device including a processor and an interface. The processor is configured to execute any one of the above-described method embodiments applicable to a first network device, a second network device, or a terminal device.

[0297] It should be understood that the aforementioned processing device may be a chip, and the processor may be implemented by hardware or software. When the processor is implemented using hardware, the processor may be a logic circuit or an integrated circuit, etc. When the processor is implemented using software, the processor may be a general-purpose processor and is implemented by reading software code stored in a memory. The memory may be integrated with the processor or may be disposed outside the processor and exist independently.

[0298] The above description is only a specific implementation form of this application and is not intended to limit the protection scope of the embodiments of this application. All deformations and substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of this application are included in the protection scope of the embodiments of this application. Therefore, the protection scope of the embodiments of this application shall be subject to the protection scope of the claims.

Description of Reference Signs

[0299] 120 Core Network Element 900 Communication Device 901 Central Unit 902 Distributed Unit 1000 Communication Device 1010 Processing Module 1020 Transmission Module 1030 Reception Module 1101 Access Network Device 1102 Access Network Device 1110 Antenna 1120 Radio Frequency Device 1130 Signal Processing Unit 1131 Processing Element 1132 Storage Element 1133 Interface Circuit 1301 Terminal Device 1302 Terminal Device 9010 Processing Module 9020 Transmission Module 9030 Receiver Module

Claims

Claim 1 A communication method, the method comprising: a step of transmitting, by a central unit of a first network device, a Radio Resource Control (RRC) release message to a distributed unit of the first network device, wherein the RRC release message carries a suspend configuration and indication information, the suspend configuration indicates a terminal device to be switched to an inactive state, and the indication information instructs to store a context of the terminal device; a step of receiving, by the central unit of the first network device, a User Equipment (UE) context search request from a second network device; a step of transmitting, by the central unit of the first network device, a context of the terminal device in the inactive state to the second network device; after the step of receiving the UE context search request, a step of transmitting, by the central unit of the first network device, a first message to the distributed unit of the first network device, wherein the first message indicates to the distributed unit of the first network device to release the stored context of the terminal device; wherein the stored context includes a configured grant configured for the terminal device, the configured grant includes a first resource, and the first resource is used by the terminal device to transmit data in an inactive state; a method. Claim 2 The method further comprising: a step of performing identity verification by the first network device with reference to a security context within the first network device and verification information within the UE context search request. The method according to claim 1. Claim 3 The step of transmitting, by the central unit of the first network device, a first message to the distributed unit of the first network device includes: after the identity verification is successful, a step of transmitting, by the central unit of the first network device, the first message to the distributed unit of the first network device. The method according to claim 2. Claim 4 the released context includes configuration information of a physical downlink control channel (PDCCH) configured for the terminal device, a temporary identifier for scrambling the PDCCH, an inactive radio network temporary identifier (I-RNTI) configured for the terminal device, and configuration information of a radio link control (RLC) layer corresponding to a radio bearer configured for the terminal device, and the method according to any one of claims 1 to 3 further includes one or more of them.

5. Before the step of receiving, by a central unit of a first network device, a user equipment (UE) context search request from a second network device, the terminal device in the inactive state is configured to transmit data to the first network device, and the method according to any one of claims 1 to 4.

6. A communication method, the method includes: A step of transmitting, by a central unit of a first network device, a radio resource control RRC release message to a distributed unit of the first network device, where the RRC release message carries a suspend configuration and indication information, the suspend configuration indicates a terminal device to be switched to an inactive state, and the indication information instructs to store the context of the terminal device; A step of receiving, by the central unit of the first network device, a user equipment (UE) context search request received from a second network device; A step of transmitting, by the central unit of the first network device, the context of the terminal device in the inactive state to the second network device; After the step of receiving the UE context search request, a step of transmitting, by the central unit of the first network device, a first message to the distributed unit of the first network device, where the first message indicates to the distributed unit of the first network device to release the stored context of the terminal device; A step of receiving, by the distributed unit of the first network device, the first message, the stored context includes including a configured grant configured for the terminal device, the configured grant including a first resource, the first resource being used by the terminal device to transmit data in an inactive state Method. Claim 7 wherein the method further includes the step of performing identity verification by the first network device with reference to the security context within the first network device and the verification information within the UE context search request, according to the method of claim 6 Claim 8 wherein the step of transmitting a first message from the central unit of the first network device to the distributed unit of the first network device includes the step of transmitting the first message from the central unit of the first network device to the distributed unit of the first network device after the identity verification is successful, according to the method of claim 7 Claim 9 wherein the released context configuration information of a physical downlink control channel (PDCCH) configured for the terminal device, a temporary identifier for scrambling the PDCCH, an inactive radio network temporary identifier (I-RNTI) configured for the terminal device, or configuration information of a radio link control (RLC) layer corresponding to a radio bearer configured for the terminal device, and further includes one or more of the above, according to the method of any one of claims 6 to 8 Claim 10. Before the step of receiving a user equipment (UE) context search request from a second network device by the central unit of the first network device, the terminal device in the inactive state is configured to transmit data to the first network device, according to the method of any one of claims 6 to 9 Claim 11 wherein the method further includes the step of receiving, by the distributed unit of the first network device, instruction information for storing the context of the terminal device, and the step of storing the context of the terminal device according to the instruction information, according to the method of any one of claims 6 to 10 Claim 12 A communication device comprising a unit or module configured to execute the method according to any one of claims 1 to 5.

13. A communication device comprising a processor and a memory, wherein the processor is coupled to the memory and configured to control the device to implement the method according to any one of claims 1 to 5.

14. A computer-readable storage medium storing instructions which, when run on a computer, enable the computer to execute the method according to any one of claims 1 to 5.

15. A communication system comprising a central unit of a first network device for executing the method according to any one of claims 1 to 5 and a distributed unit of the first network device.

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