Communication method and communication apparatus

Abstract

The present application provides a communication method and a communication apparatus. A relay terminal device can store a first context for transmitting small packet data between a remote terminal device and a network device, and if a small packet data transmission condition is satisfied, the relay terminal device can recover the first context and transmit in an RRC non-connected state first small packet data between the remote terminal device and the network device, thereby avoiding the problem of power consumption and signaling overhead caused by the relay terminal device needing to enter an RRC connected state to transmit the first small packet data between the remote terminal device and the network device.

Description

Communication method and communication device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on September 22, 2023, with application number 202311242923.3 and application name “Communication Method and Communication Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communications, and more particularly to a communication method and a communication device in the field of communications. Background Art

[0003] In the field of wireless communication technology, a terminal device exists in three states at the radio resource control (RRC) layer: RRC connected (RRC_CONNECTED), RRC idle (RRC_IDLE), and RRC inactive (RRC_INACTIVE). Generally, data can only be transmitted between the terminal device and the network device when the terminal device is in the RRC_CONNECTED state. If no data from the terminal device is transmitted between the terminal device and the network device within a preset period of time in the RRC_CONNECTED state, the terminal device may enter the RRC_INACTIVE state.

[0004] However, in some business scenarios, terminal devices in the RRC IDLE or RRC INACTIVE states need to transmit data, and the data packets to be transmitted are very small, which can be called small data. Examples of such data packets are instant messaging messages, heartbeat packets, and periodic data. To transmit small data, the terminal device needs to enter the RRC_CONNECTED state from the RRC_INACTIVE state. However, the signaling required for the terminal device to enter the RRC CONNECTED state from the RRC IDLE or RRC INACTIVE state is even greater than that for small data, resulting in unnecessary power consumption and signaling overhead for the terminal device.

[0005] Summary of the Invention

[0006] An embodiment of the present application provides a communication method and a communication device, in which a relay terminal device can be in an RRC non-connected state to transmit the first packet data between a remote terminal device and a network device, thereby avoiding the power consumption and signaling overhead problems caused by the relay terminal device needing to enter an RRC connected state.

[0007] In a first aspect, a communication method is provided, which is characterized in that it is applied to a relay terminal device, including: saving a first context for transmitting packet data between a remote terminal device and a network device; if the transmission conditions of the packet data are met, restoring the first context; and transmitting the first packet data between the remote terminal device and the network device in an RRC non-connected state based on the restored first context.

[0008] In the above scheme, the relay terminal device can save the first context used to transmit the small packet data between the remote terminal device and the network device. If the transmission conditions of the small packet data are met, the relay terminal device can restore the first context and transmit the first small packet data between the remote terminal device and the network device in the RRC non-connected state, thereby avoiding the need for the relay terminal device to enter the RRC connected state to transmit the first small packet data between the remote terminal device and the network device.

[0009] Optionally, the RRC non-connected state may be an RRC inactive state or an RRC idle state, etc.

[0010] In some possible implementations, the transmission condition includes at least one of the following: the RRC layer of the relay terminal device triggers the RRC connection recovery process, the amount of data related to the packet data transmission is less than or equal to the first data amount threshold value, the reference signal received power RSRP between the remote terminal device and the relay terminal device is greater than or equal to the first RSRP threshold value, the Uu reference signal received power RSRP of the relay terminal device is greater than or equal to the second RSRP threshold value, or the first indication information of the remote terminal device is received, and the first indication information is used to indicate that the remote terminal device has a transmission requirement for small packet data, or the second indication information sent by the network device is received, and the second indication information indicates that the network device supports the relay terminal device to transmit the small packet data between the remote terminal device and the network device in the RRC non-connected state.

[0011] Optionally, the transmission conditions under which the RRC connection recovery process is triggered by the RRC layer of the relay terminal device can be applicable to uplink transmission or downlink transmission.

[0012] Optionally, the transmission condition that the data volume related to packet data transmission is less than or equal to the first data volume threshold value is used when the remote terminal device has an uplink data transmission requirement. When the remote terminal device has an uplink data transmission requirement, the relay terminal device needs to judge the transmission condition.

[0013] Optionally, the network device may send first data volume threshold value information, and the relay terminal device may receive the first data volume threshold value information, where the first data volume threshold value information is used to indicate the first data volume threshold value. Optionally, the network device sending the first data volume threshold value information may include: the network device broadcasting the first data volume threshold value information.

[0014] Optionally, the transmission condition that the reference signal received power RSRP between the remote terminal device and the relay terminal device is greater than or equal to the first RSRP threshold value can be applicable to uplink transmission or downlink transmission.

[0015] Optionally, the network device may send first RSRP threshold value information, and the relay terminal device may receive the first RSRP threshold value information, where the first RSRP threshold value information is used to indicate the first RSRP threshold value. Optionally, the network device may send the first RSRP threshold value information, which may include: the network device may broadcast the first RSRP threshold value information. Optionally, the network device may send the first data volume threshold value information and the first RSRP threshold value information simultaneously, or may send the first data volume threshold value information and the first RSRP threshold value information separately.

[0016] Optionally, the transmission condition that the Uu RSRP of the relay terminal device is greater than or equal to the second RSRP threshold value can be applicable to uplink transmission or downlink transmission.

[0017] Optionally, the network device may send second RSRP threshold value information, and the relay terminal device may receive the second RSRP threshold value information, where the second RSRP threshold value information is used to indicate the second RSRP threshold value. Optionally, the network device may send the second RSRP threshold value information, which may include: the network device may broadcast the second RSRP threshold value information. Optionally, the network device may simultaneously send multiple items of the first data volume threshold value information, the first RSRP threshold value information, and the second RSRP threshold value information, or may separately send the first data volume threshold value information, the first RSRP threshold value information, and the second RSRP threshold value information.

[0018] Optionally, first indication information of the remote terminal device is received, where the first indication information is used to indicate that the transmission condition of the remote terminal device having a transmission requirement for small packet data is applicable to uplink transmission and may also be applicable to downlink transmission.

[0019] Optionally, the relay terminal device receives a second indication message sent by the network device, and the second indication message is used to indicate that the network device supports the relay terminal device to transmit small packet data between the remote terminal device and the network device in the RRC non-connected state. The transmission conditions are applicable to uplink transmission and may also be applicable to downlink transmission.

[0020] In some possible implementations, the amount of data associated with packet data transmission includes at least one of the size of the first packet data, the size of the second packet data of the relay terminal device, and the size of the RRC request message from the remote terminal device.

[0021] In the above scheme, if the relay terminal device also has a second packet of data to be transmitted, since the relay terminal device may send both the first packet of data and the second packet of data to the network device, the relay terminal device can determine whether the sum of the size of the first packet of data and the size of the second packet of data is less than the first data volume threshold. Since the remote terminal device will send an RRC request message to the relay terminal device in order to transmit the first packet of data, the relay terminal device needs to forward the RRC request message of the remote terminal device to the network device. Since the relay terminal device may send both the first packet of data and the RRC request message to the network device, the relay terminal device can also determine whether the sum of the size of the RRC request message from the remote terminal device and the size of the first packet of data is less than the first data volume threshold. Alternatively, the relay terminal device also receives a second packet of data, and the remote terminal device also sends an RRC request message. Since the relay terminal device may send the first packet of data, the second packet of data, and the RRC request message to the network device, the relay terminal device can determine whether the sum of the first packet of data, the second packet of data, and the RRC request message is less than the first data volume threshold. Of course, the relay terminal device can also only determine whether the first packet of data is less than or equal to the first data volume threshold.

[0022] In some possible implementations, the communication method further includes: receiving data volume information from the remote terminal device, where the data volume information is used to indicate the size of the first packet data.

[0023] Optionally, the remote terminal device may send data volume information to the relay terminal device without sending the first indication information. After the relay terminal device receives the data volume information from the remote terminal device, it implies that the remote terminal device has a transmission requirement for small packet data.

[0024] In some possible implementations, the first indication information is included in information of a media access control MAC layer; optionally, the information of the MAC layer is a MAC control element CE or a MAC subheader.

[0025] In some possible implementations, the first indication information is included in SRAP layer information. Optionally, the SRAP layer information is a SRAP subheader or a SRAP protocol data unit (PDU).

[0026] In some possible implementations, the communication method further includes: receiving third indication information, where the third indication information indicates at least one of the following:

[0027] An identifier of a Uu relay radio link control RLC channel used to transmit packet data of the remote terminal device, or an identifier of a Uu relay RLC channel used for packet data transmission SDT of the remote terminal device, or an identifier of a Uu relay RLC channel used for SDT radio bearer RB of the remote terminal device;

[0028] An identifier of a PC5 relay RLC channel used for transmitting packet data of the remote terminal device, or an identifier of a PC5 relay RLC channel used for the SDT of the remote terminal device, or an identifier of a PC5 relay RLC channel used for the SDT RB of the remote terminal device;

[0029] The identifier of the radio bearer RB of the remote terminal device used to transmit packet data, the identifier of the RB corresponds to the identifier of the Uu relay RLC channel and the identifier of the PC5 relay RLC channel.

[0030] In some possible implementations, the saving of the first context for transmitting packet data between the remote terminal device and the network device includes: saving the first context for transmitting packet data between the remote terminal device and the network device based on the third indication information.

[0031] In the above solution, the relay terminal device can save the first context according to the third indication information, so that the relay terminal device does not know how to save the first context.

[0032] In some possible implementations, the first context includes first configuration information of the PC5 relay RLC channel corresponding to the identifier of the PC5 relay RLC channel, second configuration information of the Uu relay RLC channel corresponding to the identifier of the Uu relay RLC channel, PC5 Sidelink Relay Adaptation Protocol SRAP configuration, Uu SRAP configuration or at least one of the third indication information.

[0033] Optionally, the first configuration information of the PC5 relay RLC channel corresponding to the identifier of the PC5 relay RLC channel and / or the PC5 SRAP configuration is used to receive the first packet data from the remote terminal device, or to send the first packet data to the remote terminal device.

[0034] Optionally, the second configuration information of the Uu relay RLC channel corresponding to the identifier of the Uu relay RLC channel and / or the Uu SRAP configuration is used to receive the first packet data from the network device, or to send the first packet data to the network device.

[0035] In some possible implementations, the first context includes: second configuration information of the RLC channel corresponding to the identifier of the Uu relay RLC channel, PC5 Sidelink Relay Adaptation Protocol SRAP configuration, Uu SRAP configuration, or at least one of the third indication information, and the communication method further includes:

[0036] Receive first configuration information of the RLC channel corresponding to the identifier of the PC5 relay RLC channel from the remote terminal device.

[0037] In the above scheme, the remote terminal device can receive the first configuration information of the RLC channel corresponding to the identifier of the PC5 relay RLC channel from the network device, and can send the first configuration information of the RLC channel corresponding to the identifier of the PC5 relay RLC channel to the relay terminal device.

[0038] In some possible implementations, transmitting the first packet data between the remote terminal device and the network device in an RRC non-connected state based on the restored first context includes:

[0039] receiving the first packet data from the remote terminal device based on the first configuration information;

[0040] The first packet data is sent to the network device based on the second configuration information.

[0041] In some possible implementations, the first packet data is transmitted between the remote terminal device and the network device in an RRC non-connected state based on the restored first context, including: receiving the first packet data from the network device based on the second configuration information; and sending the first packet data to the remote terminal device based on the first configuration information.

[0042] In some possible implementations, the communication method further includes: if the transmission conditions of the packet are not met, the relay terminal device requests to enter the RRC connection state, releases the first context, and obtains the second context; based on the second context, the first packet data between the remote terminal device and the network device is transmitted in the RRC connection state.

[0043] In the above scheme, if the transmission conditions of the small packet data are not met, the relay terminal device can enter the RRC connection state and release the first context. The first small packet data between the remote terminal device and the network device can be transmitted based on the second context, avoiding the power consumption caused by the relay terminal device always saving the first context.

[0044] In some possible implementations, the remote terminal device is in an RRC connected state, an RRC idle state, or an RRC inactive state.

[0045] In the above solution, the remote terminal device can be in the RRC connected state, RRC idle state or RRC inactive state to send the first packet data to the relay terminal device, that is, there is no restriction on the state of the remote terminal device.

[0046] In some possible implementations, the communication method further includes: receiving first timer information from the network device, the first timer information being used to indicate a first duration of a first timer for the relay terminal device to transmit packet data between the remote terminal device and the network device in an RRC non-connected state; wherein, transmitting the first packet data between the remote terminal device and the network device in an RRC non-connected state includes: transmitting the first packet data between the remote terminal device and the network device in an RRC non-connected state within the first duration.

[0047] In the above solution, the relay terminal device can transmit the first packet data in the RRC non-connected state within the first duration of the first timer.

[0048] On the second aspect, a communication method is provided, which is applied to a remote terminal device and includes: when there is a demand for small packet data transmission, determining whether the conditions for small packet transmission are met; if the conditions for small packet data transmission are met, sending a first indication information to the relay terminal device, wherein the first indication information is used to indicate the small packet data transmission demand of the remote terminal device.

[0049] In the above scheme, when the remote terminal device determines that the transmission conditions are met, it can send a first indication information to the relay terminal device. The remote terminal device can be in an RRC connected state or an RRC non-connected state to transmit the first packet data. The relay terminal device can be in an RRC non-connected state to transmit the first packet data between the remote terminal device and the network device. In this way, the power consumption problem caused by the relay terminal device needing to enter the RRC connected state is avoided.

[0050] In some possible implementations, the transmission condition includes at least one of the following: receiving second indication information sent by a network device, the second indication information being used to indicate that the network device supports the relay terminal device transmitting small packet data between the remote terminal device and the network device in a radio resource control RRC non-connected state;

[0051] The relay terminal device currently connected to the remote terminal device and the relay terminal device that forwards the RRC message from the network device to the remote device are the same terminal device;

[0052] A reference signal received power RSRP between the remote terminal device and the relay terminal device is greater than a second RSRP threshold value;

[0053] The data volume of the first packet data is less than or equal to the second data volume threshold.

[0054] Optionally, the remote terminal device receives a second indication message sent by the network device, and the second indication message is used to indicate that the network device supports the transmission conditions of the relay terminal device transmitting the small packet data between the remote terminal device and the network device in the wireless resource control RRC non-connected state, which can be applicable to uplink transmission or downlink transmission.

[0055] Optionally, the transmission condition that the relay terminal device to which the remote terminal device is currently connected and the relay terminal device that forwards the RRC message from the network device to the remote device are the same terminal device can be applicable to uplink transmission or downlink transmission.

[0056] Optionally, the transmission condition that the reference signal received power RSRP between the remote terminal device and the relay terminal device is greater than the second RSRP threshold value can be applicable to uplink transmission or downlink transmission.

[0057] Optionally, the transmission condition that the data volume of the first packet data is less than or equal to the second data volume threshold value can be applicable to uplink transmission.

[0058] Optionally, the second data volume threshold may be specified by a protocol or configured by a network device.

[0059] In some possible implementations, the data volume of the first packet data includes: the size of the PC5 radio link control RLC protocol data unit PDU corresponding to the first packet data and / or the size of the PC5 RLC service data unit SDU corresponding to the first packet data.

[0060] In some possible implementations, the first indication information is included in information of a media access control (MAC) layer. Optionally, the information of the MAC layer is a MAC control element (CE) or a MAC subheader.

[0061] In some possible implementations, the first indication information is included in SRAP layer information. Optionally, the SRAP layer information is a SRAP subheader or a SRAP protocol data unit (PDU).

[0062] In some possible implementations, the method further includes: receiving first configuration information of a PC5 relay radio link control RLC channel from a network device through the relay terminal device; and sending the first configuration information of the PC5 relay RLC channel to the relay terminal device.

[0063] In some possible implementations, the remote terminal device is in an RRC connected state, an RRC idle state, or an RRC inactive state.

[0064] Specifically, the description of the second aspect can refer to the description of the first aspect.

[0065] According to a third aspect, a communication method is provided, characterized in that it is applied to a first network device, comprising: sending fifth indication information to a second network device, wherein the fifth indication information is used to request the relay terminal device to transmit a first context of packet data of the remote terminal device;

[0066] The first packet data of the remote terminal device is transmitted through the relay terminal device based on the first context.

[0067] In the above scheme, when the relay terminal device moves from the coverage of the second network device to the coverage of the first network device, the first network device can obtain the first context of the relay terminal device from the second network device. The first context is used to transmit the context of the small packet data of the remote terminal device. In this way, the relay terminal device can transmit the small packet data between the remote terminal device and the first network device within the coverage of the first network device, providing a method for transmitting the small packet data of the remote terminal device in the scenario of changing the network device.

[0068] In some possible implementations, the communication method further includes: sending a sixth indication message to the second network device, the sixth indication message being used to request a third context related to packet data of a remote terminal device, the remote terminal device being connected to the relay terminal device; and transmitting the first packet data of the remote terminal device through the relay terminal device based on the third context.

[0069] In the above solution, the first network device can also request the third context related to the packet data of the remote terminal device from the second network device to avoid the first network device not knowing how to transmit the first packet data of the remote terminal device through the relay terminal device.

[0070] In some possible implementations, the fifth indication information and the sixth indication information are the same indication information, or the fifth indication information and the sixth indication information are different indication information.

[0071] In the above scheme, the first network device can request the relay terminal device to transmit the first context of the packet data of the remote terminal device and the third context related to the packet data of the remote terminal device to the second network device through an indication message or different indication messages. In this way, the signaling interaction between the first network device and the second network device can be reduced.

[0072] In some possible implementations, the fifth indication information and the sixth indication information are different indication information.

[0073] In a fourth aspect, a communication method is provided, which is applied to a relay terminal device, including: sending a seventh indication message to a network device during the transmission of packet data in an RRC non-connected state, wherein the seventh indication message is used to indicate the need for non-packet data transmission; and entering the wireless resource control RRC connected state to transmit the first non-packet data.

[0074] In the above scheme, when the relay terminal device is transmitting small packet data in the RRC non-connected state, when non-small packet data arrives, it can send the seventh indication information to the network device to indicate the transmission requirement of the non-small packet data. The relay terminal device can enter the RRC connected state to transmit the small packet data, thereby providing a method for transmitting non-small packet data during the transmission of small packet data, avoiding the problem of being unable to transmit non-small packet data.

[0075] In some possible implementations, the sending the seventh indication information to the network device includes: sending a terminal device auxiliary information message to the network device, the terminal device auxiliary information message including the seventh indication information.

[0076] In some possible implementations, the first non-packet data is non-packet data of a first remote terminal device connected to the relay terminal device; or,

[0077] The first non-packet data includes non-packet data of the relay terminal device; or,

[0078] The first non-packet data includes packet data of one or more remote terminal devices connected to the relay terminal device.

[0079] In some possible implementations, the sending seventh indication information to the network device during the transmission of the packet data in the RRC non-connected state includes:

[0080] Sending the seventh indication information to the network device during the transmission of the packet data of the relay terminal device in the RRC non-connected state; or

[0081] Sending the seventh indication information to the network device during the transmission of a packet to the second remote terminal device connected to the relay terminal device in the RRC non-connected state;

[0082] The first remote terminal device and the second remote terminal device are the same terminal device or different terminal devices.

[0083] In the above scheme, the relay terminal device can send the seventh indication information to the network device during the transmission of the packet data of the relay terminal device, or it can also send the seventh indication information to the network device during the transmission of the packet data of the second remote terminal device connected to the relay terminal device.

[0084] In a fifth aspect, embodiments of the present application provide a communication device that implements any of the above-mentioned aspects. The functions may be implemented through hardware or through hardware executing corresponding software implementations. The hardware or software includes one or more modules or units corresponding to the above-mentioned functions. For example, a transceiver module or unit, a processing module or unit, an acquisition module or unit, etc.

[0085] In a sixth aspect, an embodiment of the present application provides a communication device, comprising: a memory and a processor, the memory being used to store a computer program; the processor being used to enable the communication device to execute any one of the methods described in any of the above aspects when calling the computer program.

[0086] In a seventh aspect, an embodiment of the present application provides a chip system, which includes a processor coupled to a memory, and the processor executes a computer program stored in the memory to implement any of the methods described in any of the above aspects.

[0087] The chip system may be a single chip or a chip module composed of multiple chips.

[0088] In an eighth aspect, an embodiment of the present application provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the method described in any one of the above aspects is implemented.

[0089] In a ninth aspect, an embodiment of the present application provides a computer program product, which, when executed on a communication device, enables the communication device to execute any one of the methods described in the above aspects.

[0090] It can be understood that the beneficial effects of the fifth to ninth aspects mentioned above can be found in the relevant descriptions of the first to fourth aspects mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0091] FIG1 is a schematic diagram of a communication system provided in an embodiment of the present application.

[0092] FIG2A is a schematic diagram of the structure of the user plane air interface protocol stack provided in an embodiment of the present application.

[0093] FIG2B is a schematic diagram of the structure of the control plane air interface protocol stack provided in an embodiment of the present application.

[0094] FIG3 is a schematic diagram of the transition of the RRC state provided in an embodiment of the present application.

[0095] FIG4 is a schematic diagram of a communication method provided in an embodiment of the present application.

[0096] FIG5 is a schematic diagram of another communication method provided in an embodiment of the present application.

[0097] FIG6 is a schematic diagram of another communication method provided in an embodiment of the present application.

[0098] FIG7 is a schematic diagram of another communication method provided in an embodiment of the present application.

[0099] FIG8 is a schematic diagram of another communication method provided in an embodiment of the present application.

[0100] FIG9 is a schematic block diagram of a communication device provided in an embodiment of the present application.

[0101] FIG10 is a schematic block diagram of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0102] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0103] It should be understood that the methods, situations, categories and divisions of the embodiments in the present application are only for the convenience of description and should not constitute special limitations. The features of various methods, categories, situations and embodiments can be combined without contradiction.

[0104] It should also be understood that the terms "first," "second," and "third" in the embodiments of this application are for distinction only and should not constitute any limitation on this application. It should also be understood that in the various embodiments of this application, the order of the sequence numbers of the processes does not imply a specific order of execution. The order of execution of the processes should be determined by their functions and inherent logic, and should not constitute any limitation on the implementation of the embodiments of this application.

[0105] In the embodiments of the present application, the number of nouns, unless otherwise specified, means "singular noun or plural noun", that is, "one or more". "At least one" means one or more, and "plural" means two or more. "And / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. For example, A / B means: A or B. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c means: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, c can be single or multiple.

[0106] Furthermore, the terms "including," "having," and any variations thereof, as used in the description of this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not limited to the listed steps or units, but may optionally include other steps or units not listed, or may optionally include other steps or units inherent to the process, method, product, or apparatus.

[0107] It should be noted that in the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being more preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0108] The methods and devices provided in the embodiments of the present application are based on the same or similar technical concepts. Since the principles of solving problems by the methods and devices are similar, the implementation of the devices and methods can refer to each other, and the repeated parts will not be repeated.

[0109] FIG1 is a schematic diagram of a communication system 100 provided in an embodiment of the present application. The wireless communication device may include a network device 110 and two or more terminal devices. FIG1 takes a terminal device 120 and a terminal device 130 as an example. The terminal device 130 cannot communicate directly with the network device 110, but the terminal device 120 and the terminal device 130 can communicate directly with each other. Therefore, the terminal device 120 can act as a relay terminal device of the terminal device 130 to realize communication between the terminal device 130 and the network device 110. The terminal device 130 may also be referred to as a remote terminal device (remote UE), and the terminal device 120 may be referred to as a relay terminal device (relay UE). The link in which the terminal device 120 sends data to the network device 110 is called an uplink, and the link in which the terminal device 120 receives data sent by the network device 110 is called a downlink. The embodiments of the present application do not limit the types and quantities of the network devices and terminal devices included in the mobile communication system. The communication interface between the terminal device 120 and the network device 110 may also be referred to as a Uu interface. The communication link between terminal device 120 and terminal device 130 is called a sidelink. The communication interface between terminal device 120 and terminal device 130 may be a PC5 interface. For example, terminal device 120 may send data to terminal device 130 via the sidelink, and terminal device 130 may send data to terminal device 120 via the sidelink. Sidelinks are generally used in scenarios where direct communication between devices is possible, such as vehicle-to-everything (V2X) or device-to-device (D2D). V2X communication can be considered a special case of D2D communication.

[0110] New radio (NR) access technology is currently a mainstream wireless communication technology. It supports V2X communication with lower latency and higher reliability, tailored to the characteristics of V2X services and new service requirements. V2X is a foundational and key technology for realizing smart cars, autonomous driving, and intelligent transportation systems. V2X can include vehicle-to-network (V2N), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), and vehicle-to-pedestrian (V2P). V2N communication is currently the most widely used form of connected vehicle. Its main function is to connect vehicles to cloud servers via mobile networks, providing navigation, entertainment, anti-theft, and other applications. V2V communication can be used for information exchange and alerts between vehicles, with the most typical application being vehicle-to-vehicle collision avoidance safety systems. Through V2I communication, vehicles can communicate with roads and even other infrastructure, such as traffic lights and roadblocks, to obtain road management information such as traffic light signal timing. V2P communication can be used to provide safety warnings to pedestrians and non-motorized vehicles on the road.

[0111] The terminal device 120 or the terminal device 130 in the mobile communication system 100 may also be referred to as a terminal, user equipment (UE), mobile station (MS), mobile terminal (MT), road side unit (RSU), etc. The terminal device in the embodiment of the present application can be a mobile phone, a tablet computer, a computer with wireless transceiver function, a wearable device, a vehicle, a drone, a helicopter, an airplane, a ship, a robot, a robotic arm, a smart home device, a speaker, etc., and can also be a wireless terminal used in scenarios such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IOT), virtual reality (VR), augmented reality (AR), industrial control, self-driving, remote medical, smart grid, transportation safety, smart city, smart wear, smart transportation, and smart home. In this application, the aforementioned terminal devices and chips that can be applied to the aforementioned terminal devices are collectively referred to as terminal devices. It should be understood that the embodiments of the present application do not limit the specific technology and specific device form adopted by the terminal devices.

[0112] In the embodiment of the present application, the network device 110 may be a device in a wireless network, and the network device 110 may also be referred to as a network apparatus. For example, the network device 110 may be a radio access network (RAN) node that connects a terminal device to a wireless network, and may also be referred to as an access network device. The network device 110 includes, but is not limited to, 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 base station (e.g., a home evolved Node B, or home Node B, HNB), a baseband unit (BBU), an access point (AP) in a wireless fidelity (WIFI) system, a wireless relay node, a wireless backhaul node, a transmission point (TP), a reception point (RP), or a transmission and reception point (TRP), and may also be a network device in a 5G mobile communication system or a network device in other future network systems. For example, a next generation NodeB (gNB) or a transmission reception point (TRP) or TP in an NR system; or one or a group of antenna panels (including multiple antenna panels) of a base station in a 5G mobile communication system; or the network device 110 may also be a network node constituting a gNB or a transmission point, such as a BBU or a distributed unit (DU).

[0113] In some deployments, the network device 110 may include a centralized unit (CU) and a DU. The network device 110 may also include an active antenna unit (AAU). The CU implements some of the functions of the gNB, and the DU implements some of the functions of the gNB. For example, the CU is responsible for processing non-real-time protocols and services and implementing the functions of the radio resource control (RRC) layer. The DU is responsible for processing physical layer protocols and real-time services and implementing the functions of the radio link control (RLC) layer, the media access control (MAC) layer, and the physical (PHY) layer. In some deployments, the CU can also be divided into a centralized unit control plane (CU-CP) node and a centralized unit user plane (CU-UP) node. The CU-CP is responsible for the control plane functions, and the CU-UP is responsible for the user plane functions.

[0114] The communication system 100 shown in FIG1 may apply 4G, 5G, 6G or future communication systems, etc., and the embodiments of the present application are not limited thereto.

[0115] It should be understood that FIG1 is only for ease of understanding, and schematically shows the terminal device 120 or the terminal device 130, but this should not constitute any limitation to the present application. The wireless communication system may also not include the network device 110, or include a greater number of network devices, or may include a greater or fewer number of terminal devices. The present application does not limit this. For example, the terminal device 120 can serve as a relay device for one or more remote terminal devices. In this case, the terminal device 120 can be connected to one or more remote terminal devices.

[0116] In the following embodiments, the relay terminal device may be the terminal device 120 in FIG. 1 , and the remote terminal device may be the terminal device 130 in FIG. 1 .

[0117] For the convenience of description, the device numbers are omitted below. For example, “terminal device” refers to “terminal device 120” and “network device” refers to “network device 110”.

[0118] Figure 2A shows a schematic diagram of the structure of a user plane air interface protocol stack in a relay scenario provided by an embodiment of the present application. As shown in Figure 2A, the user plane air interface protocol stack includes but is not limited to the Uu-service data adaptation protocol (SDAP), the Uu-packet data convergence protocol (PDCP) layer, the Uu-sidelink relay adaptation protocol (SRAP) layer, the Uu-RLC layer, the Uu-MAC layer and the Uu-PHY layer, the PC5-SRAP layer, the PC5-RLC layer, the PC5-MAC layer and the PC5-PHY layer. The SDAP layer is used to map quality of service (QoS) to data radio bearers (DRBs).

[0119] Figure 2B shows a schematic diagram of the structure of the control plane air interface protocol stack in a relay scenario provided by an embodiment of the present application. As shown in Figure 2B, the control plane air interface protocol stack includes but is not limited to the Uu-radio resource control (RRC) layer, Uu-PDCP layer, Uu-SRAP layer, Uu-RLC layer, Uu-MAC layer, Uu-PHY layer, PC5-SRAP layer, PC5-RLC layer, PC5-MAC layer, and PC5-PHY layer. The RRC layer is used for control plane management.

[0120] The Uu-PDCP layer can process RRC messages on the control plane or data on the user plane. The Uu-PDCP layer can perform IP header compression to reduce the number of bits transmitted on the radio interface. The Uu-PDCP layer is also responsible for encryption of the control plane and integrity protection of transmitted data. At the receiving end, the Uu-PDCP layer performs the corresponding decryption and decompression operations. A PDCP entity can be configured for each radio bearer. The PC5-SRAP layer is used to store the mapping relationship between radio bearers (RBs) and PC5 relay RLC channel identifiers. The PC5 relay RLC channel is used for remote terminal devices or relay terminal devices to transmit small packet data between remote terminal devices and network devices. The Uu-SRAP layer is used to store the mapping relationship between RBs and Uu relay RLC channel identifiers. The Uu relay RLC channel is used for relay terminal devices to transmit small packet data between remote terminal devices and network devices. The Uu-RLC layer or PC5-RLC layer is responsible for segmentation / concatenation, retransmission control, and duplicate detection. An RLC entity can be configured for each radio bearer. The PC5-MAC layer or the Uu-MAC layer controls logical channel multiplexing, hybrid automatic repeat request retransmissions, uplink and downlink scheduling, etc. The PC5-MAC layer provides services to the PC5-RLC layer in the form of logical channels, and the Uu-MAC layer provides services to the Uu-RLC layer in the form of logical channels. The PC5-PHY layer or the Uu-PHY layer manages encoding / decoding, modulation / demodulation, multi-antenna mapping, and other types of physical layer functions. The PC5-PHY layer provides services to the PC5-MAC layer in the form of transport channels, and the Uu-PHY layer provides services to the Uu-MAC layer in the form of transport channels.

[0121] As shown in Figures 2A and 2B, the PC5-MAC layer can provide services to higher layers (such as the PC5-RLC layer) via logical channels (logical channels, LCH), and the Uu-MAC layer can provide services to higher layers (such as the Uu-RLC layer) via logical channels (logical channels, LCH). Depending on the type of information transmitted, logical channels can be classified into control channels for transmitting control information on the control plane and traffic channels for transmitting user data on the user plane. That is, in Figure 2A, the logical channel between the PC5-MAC layer and the PC5-RLC layer can be called a traffic channel, and the Uu-MAC layer and the PC5-RLC layer can be called a traffic channel. In Figure 2B, the logical channel between the PC5-MAC layer and the PC5-RLC layer can be called a control channel, and the logical channel between the Uu-MAC layer and the Uu-RLC layer can be called a control channel. Among them, control channels can include but are not limited to common control channels (CCCH) and dedicated control channels (DCCH). Traffic channels can include but are not limited to dedicated traffic channels (DTCH). CCCH can exist all the time, and terminal devices that do not have an RRC connection with the network device can also use CCCH to transmit information. DCCH can be used to transmit dedicated control information between the terminal device and the network device. DTCH can be used to transmit user data between the terminal device and the network device. Generally, DCCH and DTCH do not exist all the time, but can only be used for communication between the terminal device and the network device after the network device connected to the terminal device restores the terminal device context (terminal device context). Among them, the terminal device context includes but is not limited to the terminal device identification, radio bearer (RB) related configuration, security encryption related configuration, quality of service related configuration, etc.

[0122] At the RRC layer, a terminal device generally has three states: RRC connected (RRC_CONNECTED), RRC idle (RRC_IDLE), and RRC inactive (RRC_INACTIVE). These three states are explained below.

[0123] RRC connected state

[0124] If the terminal device establishes an RRC connection with the network device, the terminal device is in the RRC connected state. In the RRC connected state, the terminal device can establish a user plane and control plane connection with the network device; the network device and the terminal device also save the context of the terminal device's access stratum (AS); the network device can know the cell to which the terminal device belongs; the terminal device can receive data sent by the network device, and the terminal device can also send data to the network device; the terminal device can measure the channel between the terminal device and the network device, and can report the measurement results to the network device. The network device can determine whether to switch the cell to which the terminal device belongs based on the measurement results. In other words, in the RRC connected state, the terminal device and the network device can not only transmit data normally, but the network device can also manage the terminal device.

[0125] RRC idle state

[0126] If the terminal device has not established an RRC connection with the network device, the terminal device is in the RRC idle state. In the RRC idle state, the terminal device can select a PLMN, receive system messages broadcast by the network device, reselect a cell, and receive paging messages.

[0127] RRC inactive state

[0128] After the terminal device establishes an RRC connection with the network device, the terminal device enters the RRC connected state. If the terminal device has no data transmission needs with the network device within the preset time period in the RRC connected state, the network device can determine that the terminal device has entered the RRC inactive state, and the network device can send an RRC release (RRCRelease with suspend indication) message carrying a suspension indication to the terminal device. After the terminal device receives the RRCRelease with suspend indication message, the terminal device retains its own context and enters the RRC inactive state. In the RRC_INACTIVE state, the terminal device can save the context information of the terminal device and only temporarily disconnect the RRC connection with the network device. When the terminal device has data to transmit, the terminal device can send an RRC recovery request message to the network device.

[0129] Among them, the above three states at the RRC layer can be converted to each other. As shown in Figure 3, when the terminal device is in the RRC connected state, the network device can send an RRC release message to the terminal device, and the terminal device can release the RRC connection between it and the network device and enter the RRC idle state. When the terminal device is in the RRC idle state, it can send an RRC establishment request message to the network device, and the network device can establish an RRC connection with the terminal device based on the RRC establishment request message, so that the terminal device can enter the RRC connected state. When the terminal device is in the RRC connected state, the network device can send an RRC release (RRC release with suspend indication) message carrying a suspension indication to the terminal device. After receiving the RRC release with suspend indication message, the terminal device enters the RRC inactive state. When the terminal device is in the RRC inactive state, if there is data to be transmitted, the terminal device may send an RRC resume request message to the network device, and the network device may send an RRC resume response message to the terminal device. After receiving the resume response message, the terminal device may send an RRC resume complete message to the network device, and the terminal device enters the RRC connected state and resumes using the context of the terminal device. It can be understood that the speed of the terminal device entering the RRC connected state from the RRC inactive state is faster than entering the RRC connected state from the RRC idle state. If the terminal device is in the RRC inactive state, the network device may send an RRC release message to the terminal device, and the terminal device enters the RRC idle state.

[0130] When a terminal device needs to transmit data to a network device in an RRC inactive state, the terminal device may send an RRC resume request message to the network device, and the network device may send an RRC resume response message to the terminal device. After receiving the RRC resume response message, the terminal device may send an RRC resume completion message to the network device, and the terminal device enters an RRC connected state. In some scenarios, the data that the terminal device needs to transmit to the network device in the RRC inactive state is very small, and these data are called small data or small packet data. For example, small data or small packet data may include instant messages from the terminal device's application (APP), heartbeat packets from the APP, or push messages from the APP; for another example, small data or small packet data may include: periodic data from a wearable device, business data from an IoT device, etc. The signaling overhead of the terminal device entering the RRC connected state from the RRC inactive state is even greater than the overhead of transmitting these small data itself. Therefore, the terminal device may incur excessive overhead in order to transmit very small data. Especially in relay scenarios, if a remote terminal device needs to transmit small data packets, the remote terminal device needs to enter the RRC connected state to transmit the small data packets. If the relay terminal device needs to forward data for the remote terminal device and also enter the RRC connected state, the signaling overhead of entering the RRC connected state will be greater. Therefore, in relay scenarios, how the relay terminal device transmits small data packets to the remote terminal device in the RRC idle state or RRC inactive state (hereinafter collectively referred to as the RRC non-connected state) is an urgent problem to be solved.

[0131] The terminal device in the definition of the three connection states of the RRC layer above can be a relay terminal device or a remote terminal device. It should be noted that in the relay scenario, the three connection states of the RRC layer can be understood as the RRC connection state between the relay terminal device and the network device, or the RRC connection state between the remote terminal device and the network device.

[0132] In an embodiment of the present application, small data or small packet data needs to meet at least one of the following conditions: the data volume is less than or equal to a preset threshold value, and the data comes from a small data transmission (SDT) SRB or SDT DRB. For example, the preset threshold value can be 500 bytes, 300 bytes, etc. Optionally, the network device and the terminal device can also determine whether the data is small data or small packet data based on the data label or data type, wherein the network device and the terminal device can also negotiate the data label or data type according to the size of the data. For example, the data label can include a label for big data or a label for small data; for another example, data whose data type is a heartbeat packet, an instant message, or periodic data is small data, and data whose data type is a file, video, or audio is big data.

[0133] In an embodiment of the present application, the relay terminal device can save a first context for transmitting small packet data between the remote terminal device and the network device. If the transmission conditions of the small packet data are met, the relay terminal device can restore the first context and transmit the first small packet data between the remote terminal device and the network device in the RRC non-connected state, thereby avoiding the need for the relay terminal device to enter the RRC connected state to transmit the first small packet data between the remote terminal device and the network device.

[0134] The communication method according to an embodiment of the present application is described below with reference to FIG4 . As shown in FIG4 , the communication method 400 includes:

[0135] S410: The relay terminal device saves a first context for transmitting packet data between the remote terminal device and the network device.

[0136] Optionally, before S410, the communication method 400 includes: the relay terminal device may receive third indication information, where the third indication information is used to indicate information related to the transmission of packet data between the remote terminal device and the network device. Optionally, the relay terminal device may save a first context for transmitting packet data between the remote terminal device and the network device based on the third indication information. Optionally, the relay terminal device may receive a first RRC response message sent by the network device, where the first RRC response message may include the third indication information.

[0137] It should be understood that the embodiment of the present application does not limit the function of the third indication information. For example, the third indication information is used to indicate relay SDT information, or the third indication information is used to instruct the relay terminal device to save the context of the relay SDT, etc. Relay SDT can be understood as the relay terminal device performing packet data transmission between the remote terminal device and the network device.

[0138] Optionally, the third indication information may indicate information of a Uu relay RLC channel used for transmitting small packet data of a remote terminal device, or may indicate information of a Uu relay RLC channel used for small data transmission (SDT) of a remote terminal device, or information of a Uu relay RLC channel used for an SDT radio bearer (RB) of a remote terminal device, or information of a Uu relay RLC channel corresponding to an SDT RB of a remote terminal device. The information of the Uu relay RLC channel is used to identify the Uu relay RLC channel. Optionally, the information of the Uu relay RLC channel may be an identifier of the Uu relay RLC channel, that is, the third indication information may indicate an identifier of a Uu relay RLC channel used for transmitting small packet data of a remote terminal device, or may indicate an identifier of a Uu relay RLC channel used for SDT of a remote terminal device, or an identifier of a Uu relay RLC channel used for an SDT radio bearer (RB) of a remote terminal device, or an identifier of a Uu relay RLC channel corresponding to an SDT RB of a remote terminal device. Optionally, the third indication information may indicate identifiers of one or more Uu relay RLC channels. For example, the third indication information may indicate a first list, and the first list includes identifiers of one or more Uu relay RLC channels.

[0139] Optionally, the third indication information may indicate information about a PC5 relay RLC channel used for transmitting packet data of a remote terminal device, or information about a PC5 relay RLC channel used for the SDT of the remote terminal device, or information about a PC5 relay RLC channel used for the SDT RB of the remote terminal device, or information about a PC5 relay RLC channel corresponding to the SDT RB of the remote terminal device. The information about the PC5 relay RLC channel is used to identify the PC5 relay RLC channel. Optionally, the information about the PC5 relay RLC channel may be an identifier of the PC5 relay RLC channel, and the third indication information may indicate an identifier of the PC5 relay RLC channel used for transmitting packet data of the remote terminal device, or an identifier of the PC5 relay RLC channel used for the SDT of the remote terminal device, or an identifier of the PC5 relay RLC channel used for the SDT RB of the remote terminal device, or an identifier of the PC5 relay RLC channel corresponding to the SDT RB of the remote terminal device. Optionally, the third indication information may indicate identifiers of one or more PC5 relay RLC channels. For example, the third indication information may indicate a second list, and the second list includes identifiers of one or more PC5 relay RLC channels.

[0140] Optionally, the third indication information may also indicate information about the RB of the remote terminal device used to transmit packet data, or information about the SDT RB of the remote terminal device, wherein the information about the RB corresponds to the Uu relay RLC channel, or may correspond to the PC5 relay RLC channel, so that the relay terminal device may save the second configuration information of the Uu relay RLC channel corresponding to the information about the RB, or may save the first configuration information of the PC5 relay RLC channel corresponding to the information about the RB. The information about the RB is used to identify the RB. Optionally, the information about the RB may be an identifier of the RB. That is, the third indication information may indicate an identifier of the RB of the remote terminal device used to transmit packet data, or an identifier of the SDT RB of the remote terminal device, and the third indication information may indicate identifiers of one or more RBs. For example, the third indication information may indicate a third list, and the third list includes identifiers of one or more RBs.

[0141] Optionally, before S410, the relay terminal device may be in an RRC connected state or an RRC inactive state, and the network device may send an RRC release message, the RRC release message may include a pause indication, the RRC release message may release the RRC connection between the relay terminal device and the network device, and the relay terminal device enters the RRC inactive state according to the pause indication in the RRC release message. Optionally, the relay terminal device may save the first context for transmitting small packet data between the remote terminal device and the network device according to the pause indication in the RRC release message. Optionally, the first RRC response message may be an RRC release message, that is, the first RRC response message may include a pause indication, and the relay terminal device may save the first context for transmitting small packet data between the remote terminal device and the network device according to the pause indication. Optionally, the relay terminal device can save the context of the relay terminal device according to the pause indication in the RRC release message. The context of the relay terminal device may include a context for transmitting data between the relay terminal device and the network device, and a first context for transmitting packet data between the remote terminal device and the network device. In other words, the pause indication in the RRC release message can trigger the relay terminal device to save the context. The relay terminal device can save the context for its own data transmission and the first context for transmitting packet data between the remote terminal device and the network device.

[0142] Optionally, before S410, the relay terminal device may be in an RRC connected state or an RRC inactive state, and the network device may send an RRC release message, which may include a pause indication and a third indication information. The RRC release message may release the RRC connection between the relay terminal device and the network device, and the relay terminal device enters the RRC inactive state according to the pause indication in the RRC release message. Optionally, the first RRC response message may be an RRC release message, that is, the first RRC response message may include a pause indication and a third indication information. Optionally, the relay terminal device may save the first context for transmitting packet data between the remote terminal device and the network device according to the pause indication and / or the third indication information in the first RRC response message.

[0143] Optionally, the first context includes first configuration information of the PC5 relay RLC channel corresponding to the identifier of the PC5 relay RLC channel between the relay terminal device and the connected remote terminal device, second configuration information of the Uu relay RLC channel corresponding to the identifier of the Uu relay RLC channel, PC5 SRAP configuration, Uu SRAP configuration or at least one of the third indication information. Optionally, the relay terminal device may save a first context related to packet transmission of one or more remote terminal devices connected to the relay terminal device, for example, the first context related to packet transmission of remote terminal device 1 connected to the relay terminal device includes: first configuration information of the PC5 relay RLC channel corresponding to the identifier of the PC5 relay RLC channel between the relay terminal device and the remote terminal device 1, second configuration information of the Uu relay RLC channel corresponding to the identifier of the Uu relay RLC channel, PC5 SRAP configuration, Uu SRAP configuration or at least one of the third indication information; the first context related to packet transmission of remote terminal device 2 connected to the relay terminal device includes: first configuration information of the PC5 relay RLC channel corresponding to the identifier of the PC5 relay RLC channel between the relay terminal device and the remote terminal device 2, second configuration information of the Uu relay RLC channel corresponding to the identifier of the Uu relay RLC channel, PC5 SRAP configuration, Uu SRAP configuration or at least one of the third indication information.

[0144] Optionally, the first context may include at least one of the second configuration information of the Uu relay RLC channel corresponding to the identifier of the Uu relay RLC channel, the PC5 SRAP configuration, the Uu SRAP configuration, or the third indication information. The remote terminal device may receive the first configuration information of the PC5 relay RLC channel from the network device through the relay terminal device in the RRC connected state, and the remote terminal device may send the first configuration information of the PC5 relay RLC channel to the relay terminal device. For example, the remote terminal device may send the first configuration information of the PC5 relay RLC channel to the relay terminal device through a PC5-S connection or a PC5-RRC connection, so that the relay terminal device may obtain the first configuration information of the PC5 relay RLC channel from the remote terminal device. Optionally, the relay terminal device can save a first context related to packet transmission of one or more remote terminal devices connected to the relay terminal device. For example, the first context related to packet transmission of the remote terminal device 1 connected to the relay terminal device includes the second configuration information of the Uu relay RLC channel corresponding to the identifier of the Uu relay RLC channel between the relay terminal device and the remote terminal device 1, PC5 SRAP configuration, Uu SRAP configuration or at least one of the third indication information. The remote terminal device 1 can receive the first configuration information of the PC5 relay RLC channel from the network device through the relay terminal device in the RRC connection state, and the remote terminal device 1 can send the first configuration information of the PC5 relay RLC channel to the relay terminal device through the PC5-S connection or the PC5-RRC connection; the first context related to packet transmission of the remote terminal device 2 connected to the relay terminal device also includes the second configuration information of the Uu relay RLC channel corresponding to the identifier of the Uu relay RLC channel between the relay terminal device and the remote terminal device 2, PC5 SRAP configuration, Uu SRAP configuration or at least one of the third indication information, the remote terminal device 2 can receive the first configuration information of the PC5 relay RLC channel from the network device through the relay terminal device in the RRC connection state, and the remote terminal device 2 can send the first configuration information of the PC5 relay RLC channel to the relay terminal device through the PC5-S connection or the PC5-RRC connection.

[0145] Optionally, the first context may include at least one of the second configuration information of the Uu relay RLC channel corresponding to the identifier of the Uu relay RLC channel, the Uu SRAP configuration, or the third indication information. The remote terminal device may receive the first configuration information and the PC5 SRAP configuration of the PC5 relay RLC channel from the network device through the relay terminal device in the RRC connected state, and the remote terminal device may send the first configuration information and the PC5 SRAP configuration of the PC5 relay RLC channel to the relay terminal device. For example, the remote terminal device may send the first configuration information and the PC5 SRAP configuration of the PC5 relay RLC channel to the relay terminal device through a PC5-S connection or a PC5-RRC connection, so that the relay terminal device may obtain the first configuration information and the PC5 SRAP configuration of the PC5 relay RLC channel from the remote terminal device. Optionally, the relay terminal device can save the first context related to the packet transmission of one or more remote terminal devices connected to the relay terminal device. For example, the first context related to the packet transmission of the remote terminal device 1 connected to the relay terminal device includes the second configuration information of the Uu relay RLC channel corresponding to the identifier of the Uu relay RLC channel, the Uu SRAP configuration or at least one of the third indication information. The remote terminal device 1 can receive the first configuration information and PC5 SRAP configuration of the PC5 relay RLC channel from the network device through the relay terminal device in the RRC connection state. The remote terminal device 1 can send the first configuration information and PC5 SRAP configuration of the PC5 relay RLC channel to the relay terminal device through the PC5-S connection or the PC5-RRC connection; the first context related to the packet transmission of the remote terminal device 2 connected to the relay terminal device can include the second configuration information of the Uu relay RLC channel corresponding to the identifier of the Uu relay RLC channel, the Uu SRAP configuration or at least one of the third indication information, the remote terminal device 2 can receive the first configuration information and PC5 SRAP configuration of the PC5 relay RLC channel from the network device through the relay terminal device in the RRC connection state, and the remote terminal device 2 can send the first configuration information and PC5 SRAP configuration of the PC5 relay RLC channel to the relay terminal device through the PC5-S connection or the PC5-RRC connection.

[0146] Optionally, the first configuration information may include configuration information of a PC5 relay RLC channel used when the relay terminal device sends information to the remote terminal device, and / or configuration information of a PC5 relay RLC channel used when the remote terminal device sends information to the relay terminal device.

[0147] That is to say, the first context is the context of the relay terminal device for executing relay-related services, or the context of executing relay-related packet services.

[0148] Optionally, the relay terminal device can also save Uu-related contexts. For example, the Uu-related contexts may include: at least one of: RLC configuration, PDCP configuration or SDAP configuration. That is, the Uu-related contexts are used to transmit data between the relay terminal device and the network device. The relay terminal device can use the Uu-related contexts in the process of transmitting data with the network device.

[0149] Optionally, if a connection between the relay terminal device and the remote terminal device (such as a PC5-RRC connection or a PC5-S connection) exists, the relay terminal device can save the first context; if the connection between the relay terminal device and the remote terminal device is disconnected or released, the relay terminal device can delete or release the first context.

[0150] S420: If the transmission conditions of the small packet data are met, the relay terminal device restores the first context.

[0151] Optionally, S420 may include: if the transmission condition of the small packet data is met, restoring the first context when initiating an RRC connection recovery process for small packet data transmission.

[0152] Optionally, if the relay terminal device saves the first context according to the third indication information, the relay terminal device may restore the first context according to the third indication information.

[0153] Optionally, if the relay terminal device saves the first context for transmitting packet data between the remote terminal device and the network device according to the pause indication in the RRC release message, the relay terminal device can restore the first context for transmitting packet data between the remote terminal device and the network device. Optionally, the RRC release message may not include the third indication information. In this case, the relay terminal device can restore the first context for transmitting packet data between the remote terminal device and the network device and the context of non-packet data (which can also be understood as all relay-related contexts), or the relay terminal device may not be able to determine which PC5 and / or Uu relay RLC channels are used to transmit packet data between the remote terminal device and the network device, so the relay terminal device can determine that the transmission of packet data between the remote terminal device and the network device is not supported. Optionally, the relay terminal device can also restore the context used to transmit its own data.

[0154] Optionally, if the relay terminal device saves the first context for transmitting small packet data between the remote terminal device and the network device according to the pause indication in the RRC release message, if the RRC release message also includes third indication information, the relay terminal device can restore the first context for transmitting small packet data between the remote terminal device and the network device according to the third indication information.

[0155] Optionally, if the relay terminal device saves the first context related to the packet transmission of multiple remote terminal devices connected to the relay terminal device, the relay terminal device can also restore the first context related to the packet transmission of multiple remote terminal devices connected to the relay terminal device, or restore the first context related to the packet transmission of all remote terminal devices connected to the relay terminal device. For example, when the first remote terminal device has a packet data transmission requirement, the relay terminal device can restore the first context related to the packet transmission of the first remote terminal device, and can also restore the first context related to the packet transmission of one or more remote terminal devices other than the first remote terminal device. In this way, the relay terminal device can avoid the need to perform context recovery again when other remote terminal devices have a packet data transmission requirement while the relay terminal device is executing the packet data transmission of the first remote terminal device, thereby saving power consumption for the relay terminal device. Similarly, in addition to the first context, the relay terminal device can also simultaneously restore its own context related to packet transmission, such as SDT RB configuration, etc. In this way, it can avoid the relay terminal device needing to perform context recovery again when the relay terminal device has a packet data transmission requirement during the process of executing the packet data transmission of the first remote terminal device, thereby saving power consumption for the relay terminal device.

[0156] The following discusses the transmission conditions of small packet data in different situations.

[0157] In case 1, the transmission conditions of the small packet data include that the RRC layer of the relay terminal device triggers the RRC connection recovery process.

[0158] That is to say, in order to transmit its own small packet data, the remote terminal device can send an RRC request message to the relay terminal device. For example, if the remote terminal device is in the RRC idle state, the RRC request message can be an RRC establishment request message. For another example, if the remote terminal device is in the RRC inactive state, the RRC request message can be an RRC recovery request message. After the relay terminal device receives the RRC request message from the remote terminal device, in order to send the remote terminal device's RRC request message to the network device, but the relay terminal device is currently in the RRC non-connected state, the relay terminal device can initiate an RRC connection recovery process, and the RRC layer of the relay terminal device can also send its own RRC recovery request message to the network device.

[0159] Optionally, the remote terminal device sending an RRC request message to the relay terminal device may include: the remote terminal device sending an RRC request message to the relay terminal device through a PC5-S connection or a PC5-RRC connection with the relay terminal device. Optionally, the remote terminal device may use a default configuration (e.g., a default SL-RLC0 configuration) to send an RRC request message to the relay terminal device, and the relay terminal device may also use a default configuration (e.g., a default SL-RLC0 configuration) to receive the RRC request message sent by the remote terminal device. Optionally, the remote terminal device may restore the PDCP context and use the default configuration to send an RRC request message to the relay terminal device.

[0160] In the second case, the transmission condition of the small packet data includes that the data volume related to the small packet data transmission is less than or equal to the first data volume threshold value.

[0161] Optionally, the amount of data associated with packet data transmission may include at least one of the size of the first packet data of the remote terminal device, the size of the second packet data of the relay terminal device, or the size of the RRC request message from the remote terminal device. That is, if the relay terminal device also has the second packet data to be transmitted, since the relay terminal device may send both the first packet data and the second packet data to the network device, the relay terminal device can determine whether the sum of the size of the first packet data and the size of the second packet data is less than the first data amount threshold. Since the remote terminal device will send an RRC request message to the relay terminal device in order to transmit the first packet data, the relay terminal device needs to forward the RRC request message of the remote terminal device to the network device. Since the relay terminal device may send both the first packet data and the RRC request message to the network device, the relay terminal device can also determine whether the sum of the size of the RRC request message from the remote terminal device and the size of the first packet data is less than the first data amount threshold. Alternatively, the relay terminal device also receives a second packet of data, and the remote terminal device also sends an RRC request message. Since the relay terminal device may send the first packet of data, the second packet of data, and the RRC request message to the network device, the relay terminal device can determine whether the sum of the first packet of data, the second packet of data, and the RRC request message is less than the first data volume threshold. Of course, the relay terminal device can also only determine whether the first packet of data is less than or equal to the first data volume threshold.

[0162] Optionally, the remote terminal device sending an RRC request message to the relay terminal device may include: the remote terminal device sending an RRC request message to the relay terminal device through a PC5-S connection or a PC5-RRC connection with the relay terminal device. Optionally, the remote terminal device may use a default configuration (e.g., a default SL-RLC0 configuration) to send an RRC request message to the relay terminal device, and the relay terminal device may also use a default configuration (e.g., a default SL-RLC0 configuration) to receive the RRC request message sent by the remote terminal device. Optionally, the remote terminal device may restore the PDCP context and use the default configuration to send an RRC request message to the relay terminal device.

[0163] Optionally, the remote terminal device may send data volume information to the relay terminal device. The data volume information may indicate the size of the first packet data, where the size of the first packet data may be replaced by the data volume of the first packet data, etc. Optionally, the remote terminal device may also determine whether the transmission conditions for the packet data are met. If the remote terminal device determines that the transmission conditions for the packet data are met, the remote terminal device may send the data volume information to the relay terminal device. Optionally, if the remote terminal device needs to send the first packet data to the network device, the data volume information may be sent to the relay terminal device. Optionally, the remote terminal device may not send the data volume information to the relay terminal device. For example, if the remote terminal device needs to receive the first packet data sent by the network device rather than send the first packet data to the network device, the remote terminal device may not send the data volume information to the relay terminal device. Optionally, the remote terminal device sending the data volume information to the relay terminal device may include: the remote terminal device sending the data volume information to the relay terminal device via a PC5-S connection or a PC5-RRC connection with the relay terminal device.

[0164] It is understandable that the second situation can be used when the remote terminal device has an uplink data transmission requirement. When the remote terminal device has an uplink data transmission requirement, the relay terminal device needs to determine the conditions corresponding to the second situation.

[0165] Optionally, the network device may send first data volume threshold value information, and the relay terminal device may receive the first data volume threshold value information, where the first data volume threshold value information is used to indicate the first data volume threshold value. Optionally, the network device sending the first data volume threshold value information may include: the network device broadcasting the first data volume threshold value information.

[0166] Case three: the transmission condition of the small packet data includes that the reference signal receiving power (RSRP) between the remote terminal device and the relay terminal device is greater than or equal to a first RSRP threshold value.

[0167] Optionally, the relay terminal device can measure the RSRP between itself and the remote terminal device. If the measured RSRP is greater than or equal to the first RSRP threshold value, it indicates that the communication quality between the relay terminal device and the remote terminal device is good, and the first packet data can be transmitted through the packet data transmission process.

[0168] Optionally, the network device may send first RSRP threshold value information, and the relay terminal device may receive the first RSRP threshold value information, where the first RSRP threshold value information is used to indicate the first RSRP threshold value. Optionally, the network device may send the first RSRP threshold value information, which may include: the network device may broadcast the first RSRP threshold value information. Optionally, in the case of situation 2, if the network device also broadcasts data volume threshold value information, the network device may simultaneously broadcast the first RSRP threshold value information and the data volume threshold value information.

[0169] Case 4: The transmission condition of the small packet data includes that the RSRP between the relay terminal device and the network device is greater than or equal to the second RSRP threshold value.

[0170] Optionally, the relay terminal device can measure the RSRP between itself and the network device. If the measured RSRP is greater than or equal to the second RSRP threshold value, it indicates that the communication quality between the relay terminal device and the network device is good, and the first packet data can be transmitted through the packet data transmission process.

[0171] Optionally, the network device may send second RSRP threshold value information, and the relay terminal device may receive the second RSRP threshold value information, where the second RSRP threshold value information is used to indicate the second RSRP threshold value. Optionally, the network device sending the second RSRP threshold value information may include: the network device may broadcast the second RSRP threshold value information. Optionally, in the case of situation 2, if the network device also broadcasts data volume threshold value information, the network device may simultaneously broadcast the second RSRP threshold value information and the data volume threshold value information. Optionally, in the case of the existence of situation three, the first RSRP threshold value in situation three may be the same as or different from the second RSRP threshold value in situation four. If they are the same, the network device may send an RSRP threshold value information (first RSRP threshold value information or second RSRP threshold value information), thereby saving signaling overhead; if they are different, the network device may send the first RSRP threshold value information and the second RSRP threshold value information respectively, so that the network device may more flexibly use the first RSRP threshold value and the second RSRP threshold value to respectively limit the range of RSRP for the relay terminal device to send small packet data. For example, the network device may simultaneously broadcast the first RSRP threshold value information and the second RSRP threshold value information. In the case of both situation two and situation three, if the network device also broadcasts the data volume threshold value information, the network device may simultaneously broadcast the first RSRP threshold value information, the second RSRP threshold value information and the data volume threshold value information.

[0172] Case five, the transmission conditions of the small packet data include the relay terminal device receiving the second indication information sent by the network device, and the second indication information is used to indicate that the network device supports the relay terminal device to transmit the small packet data between the remote terminal device and the network device in the RRC non-connected state.

[0173] That is, if the second indication information sent by the network device is used to indicate that the network device supports the relay terminal device transmitting small packet data between the remote terminal device and the network device in the RRC non-connected state, the network device may also save the first context. In this way, the network device can transmit the first small packet data to the remote terminal device through the relay terminal device based on the saved first context. If the second indication information sent by the network device indicates that the network device does not support the relay terminal device transmitting small packet data between the remote terminal device and the network device in the RRC non-connected state, or the network device does not send the second indication information, the network device may not save the first context. In other words, the network device can indicate to the relay terminal device in advance whether the network device supports the relay terminal device transmitting small packet data in the RRC non-connected state, avoiding the relay terminal device initiating the process of small packet data transmission in the RRC non-connected state, and the problem of wasted signaling and increased power consumption due to the network device's lack of support.

[0174] Optionally, the second indication information may explicitly indicate that the network device supports the relay terminal device transmitting small packet data between the remote terminal device and the network device in the RRC non-connected state. For example, a bit corresponding to the second indication information having a value of 1 indicates that the network device supports the relay terminal device transmitting small packet data between the remote terminal device and the network device in the RRC non-connected state. A bit corresponding to the second indication information having a value of 0 or the absence of the second indication information indicates that the network device does not support the relay terminal device transmitting small packet data between the remote terminal device and the network device in the RRC non-connected state. Optionally, the second indication information may also implicitly indicate that the network device supports the relay terminal device transmitting small packet data between the remote terminal device and the network device in the RRC non-connected state. For example, the network device sends first timer information, the first timer information indicating the first duration of the first timer for the relay terminal device to transmit small packet data between the remote terminal device and the network device in the RRC non-connected state. The first timer information sent by the network device may be the second indication information. While indicating the first duration, the first timer information also implicitly indicates that the network device also supports the relay terminal device transmitting small packet data between the remote terminal device and the network device in the RRC non-connected state. For another example, the data volume threshold value information sent by the network device may be the second indication information, and the data volume threshold value information is used to indicate the first data volume threshold value. That is, when the transmission conditions include Case 2 and Case 5, the network device may send the first data volume threshold value information, and the first data volume threshold value information may indicate the first data volume threshold value while also implicitly indicating that the network device supports the relay terminal device in transmitting small packet data between the remote terminal device and the network device in the RRC non-connected state. For another example, the first RSRP threshold value information and / or the second RSRP threshold value information sent by the network device may be the second indication information, and the first RSRP threshold value information may indicate the first RSRP threshold value, and the second RSRP threshold value information may indicate the second RSRP threshold value. That is, when the transmission conditions include Case 3 and Case 5, the first RSRP threshold value information sent by the network device may indicate the first RSRP threshold value while also implicitly indicating that the network device supports the relay terminal device in transmitting small packet data between the remote terminal device and the network device in the RRC non-connected state. In the case where the transmission conditions include Case 4 and Case 5, the second RSRP threshold value information sent by the network device can indicate the second RSRP threshold value and can also implicitly indicate that the network device supports the relay terminal device to transmit small packet data between the remote terminal device and the network device in the RRC non-connected state. In the case where the transmission conditions include Case 3, Case 4 and Case 5, the first RSRP threshold value information and the second RSRP threshold value information sent by the network device can indicate that the network device supports the relay terminal device to transmit small packet data between the remote terminal device and the network device in the RRC non-connected state.In other words, the network device may directly or indirectly indicate whether the network device supports the relay terminal device to transmit small packet data between the remote terminal device and the network device in the RRC non-connected state.

[0175] Alternatively, the second indication information may also indicate whether the network device supports the SDT of the remote terminal device.

[0176] Optionally, the network device may broadcast the second indication information, and the relay terminal device may receive the second indication information broadcast by the network device.

[0177] It is understandable that in order to support the relay terminal device to transmit small packet data between the remote terminal device and the network device in the RRC non-connected state, the network device also needs to save the first context. Therefore, the network device can inform the relay terminal device in advance whether the network device supports this function or feature, so as to avoid the relay terminal device initiating small packet-related processes while the network device does not support it and wastes signaling overhead and power consumption.

[0178] Case six: The transmission condition of the small packet data includes the relay terminal device receiving the first indication information of the remote terminal device, the first indication information is used to indicate the transmission requirement of the small packet data of the remote terminal device, or the remote terminal device has the transmission requirement of the small packet data.

[0179] Optionally, in some scenarios, the first indication information of situation six may not be used by the relay terminal device to determine whether the transmission conditions of the small packet data are met, but the first indication information may trigger the relay terminal device to determine whether the transmission conditions of the small packet data are met. That is to say, in some cases, the relay terminal device determines whether the transmission conditions of the small packet data are met after receiving the first indication information. The first indication information may trigger the relay terminal device to determine whether the transmission conditions of the small packet data are met; in other cases, the relay terminal device may use whether the first indication information is received as whether the transmission conditions of the small packet data are met.

[0180] Optionally, if the remote terminal device needs to send an RRC request message and also needs to send the first indication information to the relay terminal device, the remote terminal device may send the RRC request message and the first indication information to the relay terminal device at the same time, or may send the RRC request message and the first indication information in sequence respectively. Optionally, the remote terminal device may also carry the first indication information in the RRC request message and send it to the relay terminal device. Optionally, the remote terminal device may also package the first indication information and the RRC request message together and send them to the relay terminal device. In the embodiment of the present application, there is no restriction on the manner in which the remote terminal device sends the RRC request message and the first indication information to the relay terminal device.

[0181] Optionally, if the first packet data of the remote terminal device arrives, the remote terminal device may send first indication information to the relay terminal device.

[0182] Optionally, if the first packet data of the remote terminal device arrives, the remote terminal device may also determine whether the transmission condition is met, and if so, may send first indication information to the relay terminal device. The following communication method 500 describes the remote terminal device determining whether the transmission condition is met.

[0183] Optionally, in S420, the transmission condition may be one or more of the aforementioned situations one to six. The embodiment of the present application does not limit the transmission condition, or the transmission condition may also include the aforementioned six situations. If the relay terminal device determines that the aforementioned transmission condition is not met, it may release the first context, enter the RRC connection state to obtain the second context, and transmit the first packet data between the remote terminal device and the network device according to the second context. That is, the relay terminal device executes S430 when it determines that the transmission condition is met. If the transmission condition is not met, it may initiate RRC connection recovery to enter the RRC connection state, and transmit the first packet data between the remote terminal device and the network device in the RRC connection state. Optionally, if the relay terminal device determines that each of the above six situations is not met, it can release the first context and enter the RRC connection state to obtain the second context, and transmit the first packet data between the remote terminal device and the network device according to the second context. Correspondingly, in S420, the relay terminal device can determine that any one of the above six situations is met and S430 can be executed; or if it determines that any one of the above six situations is not met, it can enter the RRC connection state to transmit the first packet data between the remote terminal device and the network device. Correspondingly, in S420, the relay terminal device can determine that each of the above six situations is met and S430 can be executed.

[0184] S430, the relay terminal device transmits the first packet data between the remote terminal device and the network device in the RRC non-connected state based on the restored first context.

[0185] Optionally, S430 includes: the relay terminal device receives a first packet of data from the remote terminal device based on the first configuration information in the first context; the relay terminal device sends the first packet of data to the network device based on the second configuration information in the first context, that is, for the uplink data transmission requirement of the remote terminal device, the relay terminal device can receive the first packet of data from the remote terminal device based on the first configuration information in the first context, and send the first packet of data to the network device based on the second configuration information in the first context. Alternatively, S430 includes: the relay terminal device receives the first packet of data from the network device based on the second configuration information in the first context; the relay terminal device sends the first packet of data to the remote terminal device based on the first configuration information in the first context, that is, for the downlink data transmission requirement of the remote terminal device, the relay terminal device can receive the first packet of data from the network device based on the second configuration information, and send the first packet of data to the remote terminal device based on the first configuration information.

[0186] Optionally, the first context includes the first configuration information of the PC5 relay RLC channel corresponding to the identifier of the PC5 relay RLC channel, or the relay terminal device receives the first configuration information of the PC5 relay RLC channel from the remote terminal device, and the first context also includes the second configuration information of the Uu relay RLC channel corresponding to the identifier of the Uu relay RLC channel, the PC5 SRAP configuration, and the Uu SRAP configuration. Optionally, the relay terminal device receives a first packet data from the remote terminal device based on the first configuration information in the first context; the relay terminal device sends the first packet data to the network device based on the second configuration information in the first context, including: the relay terminal device receives the first packet data from the remote terminal device based on the first configuration information and the PC5 SRAP configuration; the relay terminal device sends the first packet data to the network device based on the second configuration information and the Uu SRAP configuration, that is, for the uplink data transmission requirements of the remote terminal device, the relay terminal device can receive the first packet data from the remote terminal device according to the first configuration information and the PC5 SRAP configuration, and send the first packet data to the network device according to the second configuration information and the Uu SRAP configuration. Specifically, the relay terminal device receives the first packet data from the remote terminal device based on the first configuration information and the PC5 SRAP configuration; the relay terminal device sends the first packet data to the network device based on the second configuration information and the Uu SRAP configuration, including: if the relay terminal device receives data on a PC5 relay RLC channel, the relay terminal device can receive the PC5 relay RLC channel data according to the first configuration information, and determine the RB corresponding to the identifier of the PC5 relay RLC channel according to the PC5 SRAP configuration. The relay terminal device can also determine the identifier of the Uu relay RLC channel corresponding to the RB according to the Uu SRAP configuration and the RB, and determine the second configuration information of the Uu relay RLC channel corresponding to the RB, so that the first packet data on the RB can be sent to the network device according to the second configuration information. Alternatively, the relay terminal device receives the first packet data from the network device based on the second configuration information in the first context; the relay terminal device sends the first packet data to the remote terminal device based on the first configuration information in the first context, including: the relay terminal device receives the first packet data from the network device based on the second configuration information and the Uu SRAP configuration, and the relay terminal device sends the first packet data to the remote terminal device based on the first configuration information and the PC5 SRAP configuration. That is, for the downlink data transmission requirements of the remote terminal device, the relay terminal device can receive the first packet data from the network device according to the second configuration information and the Uu SRAP configuration, and send the first packet data to the remote terminal device according to the first configuration information and the PC5 SRAP configuration.Specifically, the relay terminal device receives the first packet data from the network device based on the second configuration information and the Uu SRAP configuration, and the relay terminal device sends the first packet data to the remote terminal device based on the first configuration information and the PC5 SRAP configuration, including: if the relay terminal device receives data on a certain Uu relay RLC channel, it can receive the Uu relay RLC channel data according to the second configuration information, and determine the RB corresponding to the identifier of the Uu relay RLC channel according to the Uu SRAP configuration. The relay terminal device can also determine the identifier of the PC5 relay RLC channel corresponding to the RB according to the PC5 SRAP configuration and the RB, and determine the first configuration information of the PC5 relay RLC channel corresponding to the RB, so that the first packet data on the RB can be sent to the remote terminal device according to the first configuration information.

[0187] Optionally, if the network device sends a first timer information, and the first timer is used to indicate the first duration of the first timer for the relay terminal device to transmit the packet data between the remote terminal device and the network device in the RRC non-connected state, then S430 includes: transmitting the first packet data between the remote terminal device and the network device in the RRC non-connected state within the first duration. Optionally, the relay terminal device can start the first timer when initiating the RRC connection recovery process for packet data transmission or when sending the RRC request message of the relay terminal device to the network device. When the relay terminal device receives the first RRC response message of the RRC request message sent by the network device, it can stop the first timer, or the relay terminal device stops the first timer when the packet transmission fails. After the first duration ends or the first timer times out, the relay terminal device considers that the transmission process of the packet data of the remote terminal device is completed. Optionally, the relay terminal device can also enter the RRC idle state. It can be understood that the first timer is a timer dedicated to the relay terminal device to perform packet data transmission between the remote terminal device and the network device.

[0188] In the above solution, the relay terminal device can be in the RRC non-connected state to transmit the first packet data between the remote terminal device and the network device, thus avoiding the power consumption problem caused by the relay terminal device needing to enter the RRC connected state.

[0189] The following describes, in conjunction with a communication method 500, when a remote terminal device meets a transmission condition, sending first indication information. As shown in FIG5 , the communication method 500 includes:

[0190] S510: When there is a need to transmit small packet data, the remote terminal device determines whether the transmission conditions for the small packet data are met.

[0191] Optionally, if a small packet of data arrives at the remote terminal device, it indicates that there is a small packet data transmission requirement, or if the remote terminal device receives a paging message for small packet data, it indicates that there is a small packet data transmission requirement. Optionally, the paging message for small packet data can be understood as a paging message related to the small packet data, or a paging message with small packet data transmission indication information.

[0192] The following describes how the remote terminal device determines whether the transmission conditions are met, based on different situations.

[0193] In case one, the upper layer of the remote terminal device requests RRC connection recovery, such as the application layer or non-access stratum (NAS) requests RRC connection recovery, which means that the remote terminal device currently has a transmission requirement, such as the transmission requirement of uplink data or uplink signaling. That is to say, when the first packet data of the remote terminal device arrives, the upper layer will trigger or request the RRC layer to restore the RRC connection, the remote terminal device executes the RRC connection recovery process, and the remote terminal device will also send an RRC request message to the relay terminal device. It can be understood that case one can be used for the situation where the remote terminal device has an uplink data transmission requirement. When the remote terminal device has an uplink data transmission requirement, the remote terminal device needs to judge the conditions corresponding to case one.

[0194] In the second scenario, the remote terminal device receives a paging message for small packet data. Specifically, the remote terminal device may receive the paging message for small packet data via a relay terminal device. For example, the remote terminal device receives a paging message related to small packet data forwarded by the relay terminal device. When the remote terminal device receives the paging message for small packet data, it indicates that the network device has small packet data to send to the remote terminal device. It is understood that the second scenario can be used when the network device has a downlink data transmission requirement related to the remote terminal device. When the network device has a downlink data transmission requirement, the remote terminal device needs to determine the conditions corresponding to the second scenario.

[0195] Case three: the data volume of the first packet data currently arriving at the remote terminal device is less than or equal to the second data volume threshold value. The data volume of the first packet data may include the size of the PC5RLC protocol data unit (PDU) corresponding to the first packet data, and / or the size of the PC5RLC service data unit (SDU) corresponding to the first packet data. For example, the data of the remote terminal device needs to be mapped to the corresponding PC5RLC through SRAP, so the remote terminal device also needs to consider the size of the SRAP header when calculating the data volume. Optionally, the network device can send the second data volume threshold value information, the remote terminal device can receive the second data volume threshold value information, and the second data volume threshold value information can indicate the second data volume threshold value.

[0196] Optionally, the network device sending the second data volume threshold value information may include: the network device broadcasting the second data volume threshold value information. Optionally, the second data volume threshold value information may be the same as or different from the first data volume threshold value information. That is, when the second data volume threshold value information is the same as the first data volume threshold value information, the network device may broadcast one data volume threshold value, and the relay terminal device and the remote terminal device may receive the same data volume threshold value information. When the second data volume threshold value and the first data volume threshold value information are different, the network device may broadcast the first data volume threshold value information and the second data volume threshold value information.

[0197] It is understandable that situation three can be used when the remote terminal device has an uplink data transmission requirement. When the remote terminal device has an uplink data transmission requirement, the remote terminal device needs to determine the conditions corresponding to situation three.

[0198] Case 4: The RSRP between the remote terminal device and the relay terminal device is greater than or equal to the third RSRP threshold value.

[0199] Optionally, the remote terminal device can measure the RSRP between itself and the relay terminal device. If the measured RSRP is greater than or equal to a third RSRP threshold value, it indicates that the communication quality between the relay terminal device and the remote terminal device is good and the first packet data can be transmitted.

[0200] Optionally, the network device may send third RSRP threshold value information, and the remote terminal device may receive the third RSRP threshold value information, where the third RSRP threshold value information is used to indicate a third RSRP threshold value. Optionally, the network device may send the third RSRP threshold value information, which may include: the network device may broadcast the third RSRP threshold value information. In the event of situation three, if the network device also broadcasts the second data volume threshold value information, the network device may also broadcast the third RSRP threshold value information and the second data volume threshold value information simultaneously.

[0201] Optionally, in the case of situation four, the third RSRP threshold value in situation four may be the same as or different from the aforementioned first RSRP threshold value. If they are the same, the network device may send an RSRP threshold value information (first RSRP threshold value information or third RSRP threshold value information), thereby saving signaling overhead; if they are different, the network device may send the first RSRP threshold value information and the third RSRP threshold value information respectively, so that the network device may use the first RSRP threshold value and the third RSRP threshold value to respectively limit the RSRP range of the relay terminal device and the remote terminal device for sending small packet data.

[0202] Case 5: The remote terminal device receives the second indication information sent by the network device. The remote terminal device may receive the second indication information, which indicates that the network device supports SDT of the remote terminal device or that the network device supports the relay terminal device transmitting the small packet data between the remote terminal device and the network device in the RRC non-connected state. Therefore, the remote terminal device may determine that the network device supports the relay terminal device transmitting the first small packet data between the remote terminal device and the network device in the RRC non-connected state.

[0203] Optionally, the second indication information may explicitly indicate that the network device supports the relay terminal device transmitting small packet data between the remote terminal device and the network device in the RRC non-connected state. For example, the bit value corresponding to the second indication information is 1, indicating that the network device supports the relay terminal device transmitting small packet data between the remote terminal device and the network device in the RRC non-connected state. The bit value corresponding to the second indication information is 0 or the second indication information does not exist, indicating that the network device does not support the relay terminal device transmitting small packet data between the remote terminal device and the network device in the RRC non-connected state. Optionally, the second indication information may also implicitly indicate that the network device supports the relay terminal device to transmit small packet data between the remote terminal device and the network device in the RRC non-connected state. For example, the network device sends a second timer information, and the second timer information indicates the second duration of the second timer for the remote terminal device to transmit small packet data between the remote terminal device and the network device. The second timer information sent by the network device may be the second indication information. While indicating the second duration, the second timer information also implicitly indicates that the network device also supports the relay terminal device to transmit small packet data between the remote terminal device and the network device in the RRC non-connected state. That is to say, the network device sends the second timer information, indicating that the network device supports the SDT of the remote terminal device or supports the relay terminal device to transmit the SDT of the remote terminal device in the RRC non-connected state. That is to say, the second indication information in situation five may be the second timer information. For another example, the second data volume threshold value information sent by the network device may be the second indication information, and the second data volume threshold value information is used to indicate the second data volume threshold value. That is, when the transmission conditions include situation three and situation five, the network device may send the second data volume threshold value information, and the second data volume threshold value information may indicate the second data volume threshold value while also implicitly indicating that the network device supports the SDT of the remote terminal device or supports the relay terminal device to transmit the small packet data between the remote terminal device and the network device in the RRC non-connected state. For another example, the third RSRP threshold value information sent by the network device may be the second indication information, and the third RSRP threshold value information may indicate the third RSRP threshold value. If the network device sends the third RSRP threshold value information, it may imply that the network device supports the SDT of the remote terminal device or supports the relay terminal device to transmit the SDT of the remote terminal device in the RRC non-connected state. Otherwise, the network device will not send the third RSRP threshold value information. That is to say, when the transmission conditions include situation four and situation five, the third RSRP threshold value information sent by the network device can indicate the third RSRP threshold value and can also implicitly indicate that the network device supports the relay terminal device to transmit small packet data between the remote terminal device and the network device in the RRC non-connected state.In the case where the transmission conditions include Case 3 and Case 5, the second data volume threshold value information sent by the network device may indicate that the network device supports the relay terminal device transmitting small packet data between the remote terminal device and the network device in the RRC non-connected state. In other words, the network device may directly or indirectly indicate whether the network device supports the relay terminal device transmitting small packet data between the remote terminal device and the network device in the RRC non-connected state.

[0204] Optionally, the network device may broadcast the second indication information, and the remote terminal device may receive the second indication information broadcast by the network device.

[0205] It is understandable that in order to support the relay terminal device to transmit small packet data between the remote terminal device and the network device in the RRC non-connected state, the network device also needs to save the first context. Therefore, the network device can inform the remote terminal device in advance whether the network device supports this function or feature, so as to avoid the relay terminal device initiating small packet-related processes while the network device does not support it, thereby wasting signaling overhead and power consumption.

[0206] In case 6, the first small data packet currently arriving at the remote terminal device comes from an SDT RB, such as an SDT DRB or SDT SRB2. Some RBs of the remote terminal device are used to transmit small data packets. If the first small data packet comes from an RB used to transmit SDT, the remote terminal device can determine that the currently arriving first small data packet can be transmitted through the SDT process.

[0207] It is understandable that situation six can be used when the remote terminal device has an uplink data transmission requirement. When the remote terminal device has an uplink data transmission requirement, the remote terminal device needs to determine the conditions corresponding to situation six.

[0208] In case seven, the relay terminal device to which the remote terminal device is currently connected is the same terminal device as the relay terminal device that forwards the second RRC response message to the remote terminal device. The network device can release the remote terminal device via the second RRC response message. For example, the second RRC response message is an RRC release message. That is, the network device can send the second RRC response message to the remote terminal device via the relay terminal device to release the remote terminal device to an RRC unconnected state. This avoids the power consumption problem caused by the remote terminal device needing to reconnect to a new relay terminal device to forward the SDT for the remote terminal device.

[0209] Optionally, in S510, the transmission condition may be one or more of the aforementioned conditions 1 to 7. The embodiment of the present application does not limit the transmission condition. Alternatively, the transmission condition may also include the aforementioned seven conditions. If the relay terminal device determines that the aforementioned transmission conditions are not met, S520 may not be executed.

[0210] Optionally, the second RRC response message forwarded by the relay terminal device may include fourth indication information. The fourth indication information is used to indicate information related to the packet data of the remote terminal device. That is, the second RRC response message forwarded by the relay terminal device may include the fourth indication information. Optionally, the fourth indication information may indicate information about the PC5 relay RLC channel used to transmit the packet data of the remote terminal device, or information about the PC5 relay RLC channel used for the SDT of the remote terminal device, or information about the PC5 relay RLC channel used for the SDT RB of the remote terminal device, or information about the PC5 relay RLC channel corresponding to the SDT RB of the remote terminal device. The information about the PC5 relay RLC channel is used to identify the PC5 relay RLC channel. Optionally, the information about the PC5 relay RLC channel may be an identifier of the PC5 relay RLC channel, and the fourth indication information may indicate the identifier of the PC5 relay RLC channel used to transmit packet data of the remote terminal device, or the identifier of the PC5 relay RLC channel used for the SDT of the remote terminal device, or the identifier of the PC5 relay RLC channel used for the SDT RB of the remote terminal device, or the identifier of the PC5 relay RLC channel corresponding to the SDT RB of the remote terminal device. Optionally, the fourth indication information may indicate the identifiers of one or more PC5 relay RLC channels, for example, the fourth indication information may indicate a second list, and the second list includes the identifiers of one or more PC5 relay RLC channels.

[0211] Optionally, the fourth indication information may further indicate information about the RB of the remote terminal device used to transmit the packet data, or information about the SDT RB of the remote terminal device, wherein the RB information corresponds to the PC5 relay RLC channel. In this way, the relay terminal device may save the first configuration information of the PC5 relay RLC channel corresponding to the RB information. The RB information is used to identify the RB. Optionally, the RB information may be an identifier of the RB. That is, the fourth indication information may indicate an identifier of the RB of the remote terminal device used to transmit the packet data, or an identifier of the SDT RB of the remote terminal device. The fourth indication information may indicate identifiers of one or more RBs. For example, the fourth indication information may indicate a third list, and the third list includes identifiers of one or more RBs.

[0212] Optionally, the remote terminal device transmits the first packet data through the relay terminal device in the RRC non-connected state according to the fourth indication information. Optionally, the remote terminal device may save the third context according to the fourth indication information.

[0213] Optionally, before S510, the remote terminal device may be in an RRC connected state or an RRC inactive state. The network device may send an RRC release message to the remote terminal device through the relay terminal device. The RRC release message may include a suspend indication. The RRC release message may release the RRC connection between the remote terminal device and the network device, and the remote terminal device enters the RRC inactive state according to the suspend indication in the RRC release message. Optionally, the remote terminal device may save a third context for transmitting small packet data in the RRC inactive state according to the suspend indication in the RRC release message. Optionally, the second RRC response message may be an RRC release message, that is, the second RRC response message may include a suspend indication, and the remote terminal device may save a third context for transmitting small packet data in the RRC inactive state according to the suspend indication. Optionally, the remote terminal device can save the context of the remote terminal device according to the pause indication in the RRC release message. The context of the remote terminal device may include a context for transmitting non-packet data between the remote terminal device and the network device, and / or a third context for transmitting packet data between the remote terminal device and the network device. In other words, the pause indication in the RRC release message can trigger the remote terminal device to save the context, and the remote terminal device can save the context for its own transmission of non-packet data and / or the third context for transmitting its own packet data.

[0214] Optionally, before S510, the remote terminal device may be in an RRC connected state or an RRC inactive state. The network device may send an RRC release message to the remote terminal device through the relay terminal device. The RRC release message may include a suspension indication and third indication information. The RRC release message may release the RRC connection between the remote terminal device and the network device, and the remote terminal device enters the RRC inactive state according to the suspension indication in the RRC release message. Optionally, the second RRC response message may be an RRC release message, that is, the second RRC response message may include a suspension indication and third indication information. Optionally, the remote terminal device may save a third context used for transmitting packet data by the remote terminal device according to the suspension indication and / or third indication information in the second RRC response message.

[0215] Optionally, the third context includes at least one of first configuration information of a PC5 relay RLC channel corresponding to the identifier of the PC5 relay RLC channel, a PC5 SRAP configuration, or the fourth indication information. Optionally, the first configuration information may include configuration information of a PC5 relay RLC channel used when the relay terminal device sends information to the remote terminal device, and / or configuration information of a PC5 relay RLC channel used when the remote terminal device sends information to the relay terminal device.

[0216] Optionally, if the remote terminal device does not receive the fourth indication information and does not save the third context for transmitting packet data in the RRC non-connected state, the remote terminal device may enter the RRC connected state and transmit the first packet data through the relay terminal device. After the remote terminal device enters the RRC connected state, it may obtain the first configuration information of the PC5 relay RLC channel from the network device through the relay terminal device, and may also obtain the PC5 SRAP configuration from the network device through the relay terminal device. The remote terminal device may use the first configuration information of the PC5 relay RLC channel and / or the PC5 SRAP configuration to send the first packet data to the relay terminal device. The relay terminal device may use the first configuration information of the PC5 relay RLC channel and / or the PC5 SRAP configuration saved in the first context, or use the first configuration information of the PC5 relay RLC channel and / or the PC5 SRAP configuration received from the remote terminal device to receive the first packet data from the remote terminal device. The network device can send the first packet data to the relay terminal device, and the relay terminal device receives the first packet data from the network device using the second configuration information and / or Uu SRAP configuration of the Uu relay RLC channel in the saved first context. The relay terminal device can send the first packet data to the remote terminal device based on the first configuration information and / or PC5 SRAP configuration of the PC5 relay RLC channel in the first context, or using the first configuration information and / or PC5 SRAP configuration of the PC5 relay RLC channel received from the remote terminal device, and the remote terminal device receives the first packet data from the relay terminal device based on the first configuration information and / or PC5 SRAP configuration of the PC5 relay RLC channel.

[0217] S520, if the transmission conditions of the small packet data are met, the remote terminal device sends first indication information to the relay terminal device, where the first indication information is used to indicate the transmission requirements of the small packet data of the remote terminal device, or the remote terminal device has the transmission requirements of the small packet data.

[0218] Alternatively, the first indication information may indicate an SDT requirement of the remote terminal device, or indicate that small packet data has arrived at the remote terminal device, etc.

[0219] Optionally, the first indication information may directly indicate the remote terminal device's demand for transmitting small packet data or the remote terminal device's demand for transmitting small packet data, or may indirectly indicate the remote terminal device's demand for transmitting small packet data or the remote terminal device's demand for transmitting small packet data.

[0220] Optionally, the remote terminal device may send data volume information to the relay terminal device, and the relay terminal device may receive the data volume information from the remote terminal device, where the data volume information is used to indicate the size of the first packet data. Optionally, the first indication information may be data volume information, that is, the data volume information may implicitly indicate the remote terminal device's packet data transmission requirement, or the remote terminal device has a packet data transmission requirement.

[0221] Optionally, the remote terminal device may send the data volume information and the first indication information to the relay terminal device simultaneously, or may send the data volume information and the first indication information separately.

[0222] Optionally, the remote terminal device may send the first indication information to the relay terminal device, which may include: the remote terminal device may send the first indication information to the relay terminal device through a PC5-S connection or a PC5-RRC connection.

[0223] In some embodiments, the first indication information may be included in the information of the MAC layer. Optionally, the first indication information may correspond to a logical channel identity (LCID), which may be an index or value of an LCID reserved in the protocol, for example, the LCID may be any value from 20 to 55, or for another example, the first indication information may correspond to an enhanced logical channel identity (eLCID), which may be an index or value of an eLCID reserved in the protocol.

[0224] Optionally, the information of the MAC layer may be a MAC control element (CE). For example, the first MAC CE includes the first indication information. The first MAC CE is identified by an index or value of an LCID. The LCID may be any reserved value from 20 to 55, or the first MAC CE is identified by an index or value of an eLCID. Here, reserved may also be understood as not being used. The first MAC CE identified by the LCID may be understood as the MAC subheader corresponding to the first MAC CE including an LCID field, the value of the LCID field being any value from 20 to 55, and the first MAC CE identified by the eLCID may be understood as the MAC subheader corresponding to the first MAC CE including an eLCID field, the value of the eLCID field being any reserved value. For example, if the value of the LCID field in the MAC subheader corresponding to the first MAC CE is any value from 20 to 55, or the value of the eLCID field is any reserved value, it indicates that the remote terminal device sends the first indication information. Among them, the first MAC CE includes the first indication information, which may include the following multiple situations: for example, the first MAC CE includes a first bit, and if the value of the first bit is 1, it indicates that the remote terminal device sends the first indication information, and if the value of the first bit is 0, it indicates that the remote terminal device does not send the first indication information; or, if the value of the first bit is 0, it indicates that the remote terminal device sends the first indication information, and if the value of the first bit is 1, it indicates that the remote terminal device does not send the first indication information. Optionally, the first MAC CE may only include the MAC subheader corresponding to the first MAC CE, and does not include the MAC CE body. For another example, the first MAC CE includes a first field, and the first field indicates data volume information. It can be understood that the data volume information at this time is the first indication information. The remote terminal device can send the first indication information and the RRC request message at the same time. At this time, the remote terminal device can package the first MAC CE including the first indication information and the RRC request message together and send them to the relay terminal device. For example, the remote terminal device packages the first MAC CE including the first indication information and the RRC request message into a first MAC PDU, and sends the first MAC PDU to the relay terminal device.

[0225] Optionally, the information of the MAC layer may be a MAC subheader. For example, the reserved bit field in the first MAC subheader may indicate the first indication information. For example, if the reserved bit is set to 1, it indicates that the remote terminal device sends the first indication information; if the reserved bit is set to 0, it indicates that the remote terminal device does not send the first indication information; or, if the reserved bit is set to 0, it indicates that the remote terminal device sends the first indication information; if the reserved bit is set to 1, it indicates that the remote terminal device does not send the first indication information. For another example, the LCID or eLCID field included in the first MAC subheader may indicate the first indication information. For example, if the value of the LCID field is any one of 20-55, or if the value of the eLCID field is any one of the reserved values, it indicates that the remote terminal device sends the first indication information. The remote terminal device can send the first indication information and the RRC request message at the same time. At this time, the remote terminal device can package the first MAC subheader including the first indication information and the RRC request message together and send them to the relay terminal device. For example, the remote terminal device packages the first MAC subheader including the first indication information and the RRC request message into a first MAC PDU, and sends the first MAC PDU to the relay terminal device. The first MAC subheader can be a MAC subheader used to identify the RRC request message, or the first MAC subheader can also be a subheader corresponding to the first MAC CE, that is, at this time the first MAC CE only includes the MAC subheader, but does not include the MAC CE body.

[0226] In some embodiments, the first indication information may be included in the SRAP layer information. Optionally, the SRAP layer information may be an SRAP control PDU, an SRAP data PDU, or an SRAP subheader. For example, if the bit corresponding to the first indication information in the SRAP layer information is 1, it indicates that the remote terminal device has a transmission requirement for small packet data. If the bit corresponding to the first indication information in the SRAP layer information is 0, or if the first indication information does not exist in the SRAP layer information, it indicates that the remote terminal device does not have a transmission requirement for small packet data. For another example, the SRAP layer information includes a first field, and the first field indicates data volume information. It can be understood that in this case, the data volume information is the first indication information.

[0227] Optionally, method 500 further includes: S530, the remote terminal device may transmit the first packet data between the remote terminal device and the network device through the relay terminal device. Optionally, the remote terminal device may transmit the first packet data between the remote terminal device and the network device through the relay terminal device, including: the remote terminal device may send the first packet data through the relay terminal device, or the remote terminal device may receive the first packet data through the relay terminal device.

[0228] Optionally, the remote terminal device may transmit the first packet data between the remote terminal device and the network device through the relay terminal device, including: the remote terminal device may transmit the first packet data through the relay terminal device in the RRC non-connected state. For example, the remote terminal device may transmit the first packet data through the relay terminal device according to the third context in the RRC non-connected state. Optionally, the remote terminal device may transmit the first packet data through the relay terminal device according to the third context in the RRC non-connected state, including: the remote terminal device may send the first packet data to the relay terminal device or receive the first packet data from the relay terminal device according to the third context in the RRC non-connected state.

[0229] Optionally, the communication method 500 further includes: the remote terminal device may transmit the first packet data through the relay terminal device in the RRC connection state, at which time the remote terminal device may not save the above-mentioned third context, but the remote terminal device enters the RRC connection state to obtain a fourth context, and the remote terminal device transmits the first packet data through the relay terminal device in the RRC connection state according to the obtained fourth context. The remote terminal device transmits the first packet data through the relay terminal device in the RRC connection state according to the obtained fourth context, including: the remote terminal device sends the first packet data to the relay terminal device in the RRC connection state according to the obtained fourth context, or receives the first packet data from the relay terminal device.

[0230] Optionally, the network device can send a second timer information, and the remote terminal device receives the second timer information sent by the network device, the second timer is used to indicate the second duration of the second timer for the remote terminal device to transmit the packet data between the remote terminal device and the network device, and the remote terminal device can transmit the first packet data between the remote terminal device and the network device through the relay terminal device, including: transmitting the first packet data between the remote terminal device and the network device through the relay terminal device within the second duration.

[0231] Optionally, the remote terminal device may start a second timer when initiating an RRC connection recovery process for packet data transmission or when sending an RRC request message of the remote terminal device to the relay terminal device. The remote terminal device may stop the second timer when receiving an RRC response message sent by the network device in response to the RRC request message, or the remote terminal device may stop the second timer when the packet transmission fails. After the second duration ends or the second timer times out, the remote terminal device deems that the transmission process of the remote terminal device's packet data through the relay terminal device is completed. Optionally, the remote terminal device may also enter an RRC idle state. Optionally, when the first timer information exists, the second duration is greater than the first duration. Since the remote terminal device initiates the RRC recovery process first and the relay terminal device initiates the RRC recovery process later, that is, the remote terminal device starts the second timer first and the relay terminal device starts the first timer later, if the second duration is greater than the first duration, it can avoid the remote terminal device's second timer timing out and determining that the transmission has failed while the relay terminal device is performing transmission. It can be understood that the second timer is a timer dedicated to the remote terminal device performing packet data transmission between the remote terminal device and the network device.

[0232] In the above scheme, the remote terminal device can send a first indication message to the relay terminal device, the remote terminal device can be in an RRC connected state or an RRC non-connected state to transmit the first packet data, and the relay terminal device can be in an RRC non-connected state to transmit the first packet data between the remote terminal device and the network device. In this way, the power consumption problem caused by the relay terminal device needing to enter the RRC connected state is avoided.

[0233] The communication method 400 and the communication method 500 are described below in conjunction with the communication method 600, but the communication method 600 should not limit the communication method 400 and the communication method 500. As shown in FIG6, the communication method 600 may include some or all of the following steps:

[0234] S601: The network device sends a first RRC response message to the relay terminal device to release the connection between the relay terminal device and the network device. For example, the first RRC response message is an RRC release message, and the relay terminal device receives the RRC release message.

[0235] Optionally, the RRC release message may include third indication information and / or a suspension indication.

[0236] Optionally, after S601, the relay terminal device enters an RRC non-connected state, for example, enters an RRC inactive state.

[0237] Optionally, before S601, the relay terminal device may be in an RRC connected state, an RRC idle state, or an RRC inactive state. If before S601, the relay terminal device is in an RRC connected state, then before S601, the network device may send an RRC release message carrying a pause indication to release the relay terminal device to an RRC inactive state. If before S601, the relay terminal device is in an RRC inactive state, for example, before S601, the relay terminal device performs an SDT process, after the SDT process ends, the network device may send an RRC release message carrying a pause indication so that the relay terminal device continues to remain in an RRC inactive state. If before S601, the relay terminal device is in an RRC idle state, before S601, the relay terminal device may send an RRC setup request message to request to enter an RRC connected state, and the network device may send an RRC release message carrying a pause indication to release the relay terminal device to an RRC inactive state. That is, before S601, the relay terminal device can be in any RRC state, and the network device can determine to release the relay terminal device to the RRC inactive state.

[0238] For the description of the third indication information and / or the pause indication, please refer to the description of the communication method 400.

[0239] In some cases, method 600 further includes: the network device sending an RRC release message to the remote terminal device, the remote terminal device receiving the RRC release message, optionally, the RRC release message may include fourth indication information and / or a pause indication, and the second RRC response message may be an RRC release message sent by the network device to the remote terminal device. The remote terminal device may save a third context based on the fourth indication information and / or the pause indication, optionally, the third context includes at least one of the first configuration information of the PC5 relay RLC channel corresponding to the identifier of the PC5 relay RLC channel, the PC5 SRAP configuration, or the fourth indication information. The network device sending the RRC release message to the remote terminal device may be understood as the network device sending the RRC release message to the remote terminal device via the relay terminal device.

[0240] It is understandable that the remote terminal device storing the third context is an optional step, and the remote terminal device may not store the third context. In other words, the RRC release message may not include the fourth indication information, and may not include the suspension indication.

[0241] S602: The relay terminal device saves the first context.

[0242] For the description of the first context, refer to the description of S410 .

[0243] S603, the network device broadcasts the second indication information, the relay terminal device and / or the remote terminal device can receive the second indication information, and the second indication information can indicate that the network device supports the relay terminal device to transmit small packet data between the remote terminal device and the network device in the RRC non-connected state.

[0244] Optionally, in S603, the network device may further broadcast at least one of the first RSRP threshold value information, the second RSRP threshold value information, the third RSRP threshold value information, the first data volume threshold value information, the second data volume threshold value information, the first timer information, or the second timer information. Specifically, the first RSRP threshold value information, the second RSRP threshold value information, the first data volume threshold value information, and the first timer information can be found in the description of method 400, and the third RSRP threshold value information, the second data volume threshold value information, and the second timer information can be found in the description of method 500.

[0245] Optionally, in S603, the network device may broadcast the second indication information in the system information block (SIB) 1, or broadcast at least one of the first RSRP threshold value information, the second RSRP threshold value information, the third RSRP threshold value information, the first data volume threshold value information, the second data volume threshold value information, the first timer information or the second timer information.

[0246] S604: When the remote terminal device has a transmission requirement for small packet data, the remote terminal device determines whether a transmission condition for the small packet data is met.

[0247] Specifically, for S604 , please refer to the description of S510 .

[0248] S605: If the transmission conditions for the small packet data are met, the remote terminal device may send a second RRC request message and first indication information to the relay terminal device, and the relay terminal device may receive the second RRC request message and first indication information from the remote terminal device. The first indication information is used to indicate the transmission requirements of the small packet data of the remote terminal device.

[0249] At this time, the RRC request message sent by the remote terminal device to the relay terminal device in method 400 or method 500 may be a second RRC request message.

[0250] Optionally, in S605, if before S605, if the remote terminal device is in an RRC inactive state, the second RRC request message may be an RRC resume request (RRCresumeRequest). If the remote terminal device is in an RRC idle state, the second RRC request message may be an RRC establishment request message.

[0251] Optionally, in S605, the remote terminal device can send the second RRC request message and the first indication information of the remote terminal device to the relay terminal device through the PC5-S connection or the PC5-RRC connection, and the relay terminal device can receive the second RRC request message and the first indication information from the remote terminal device through the PC5-S connection or the PC5-RRC connection.

[0252] S606: If the transmission conditions of the small packet data are met, the relay terminal device restores the first context.

[0253] Specifically, for S606 , please refer to the description of S420 .

[0254] Optionally, the relay terminal device may determine whether the transmission conditions for the packet data are met based on the first indication information.

[0255] Optionally, in some scenarios, the first indication information may not be used by the relay terminal device to determine whether the transmission conditions of the small packet data are met, but the first indication information may trigger the relay terminal device to determine whether the transmission conditions of the small packet data are met. That is to say, in some cases, the relay terminal device determines whether the transmission conditions of the small packet data are met after receiving the first indication information. The first indication information may trigger the relay terminal device to determine whether the transmission conditions of the small packet data are met; in other cases, the relay terminal device may use whether the first indication information is received as whether the transmission conditions of the small packet data are met.

[0256] S607, the relay terminal device may send a first RRC request message of the relay terminal device and a second RRC request message of the remote terminal device to the network device, and the network device may receive the first RRC request message and the second RRC request message from the relay terminal device.

[0257] Optionally, the first RRC request message may include reason information, and the reason information may indicate that the reason for sending the first RRC request message is SDT requirement, for example, the remote terminal device has SDT requirement.

[0258] Optionally, the second RRC request message may include reason information, and the reason information may indicate that the reason for sending the second RRC request message is SDT requirement, for example, the remote terminal device has SDT requirement.

[0259] Optionally, the first RRC request message may include cause information, and the second RRC request message may not include cause information, or the first RRC request message does not include cause information, and the second RRC request message may include cause information, or the first RRC request message may include cause information, and the second RRC request message may include cause information. This embodiment of the present application is not limited to this.

[0260] Optionally, the relay terminal device may use RA-SDT resources or CG-SDT resources to send the first RRC request message of the relay terminal device to the network device, wherein RA-SDT may be understood as small data transmission (SDT) through random access (RA), such as sending the first RRC request message through msg3 or msgA of RA-SDT. CG-SDT may be understood as SDT through pre-configured resources (configured grant, CG), such as using CG-SDT resources to transmit the first RRC request message. Optionally, if the network device receives the first RRC request message of the relay terminal device on the RA-SDT resource or the CG-SDT resource, it indicates that there is currently an SDT requirement, that is, the network device may determine that the current relay terminal device has an SDT requirement based on the resource for receiving the first RRC request message of the relay terminal device. At this time, the first RRC request message may not carry cause information.

[0261] Optionally, the relay terminal device may send a first RRC request message of the relay terminal device to the network device through the RA resource, for example, sending the first RRC request message through msg3 or msgA.

[0262] Optionally, if the remote terminal device sends a second RRC request message of the remote terminal device to the relay terminal device, then in S607, the relay terminal device may send the first RRC request message of the relay terminal device and the second RRC request message of the remote terminal device to the network device. Optionally, if RA-SDT resources or CG-SDT resources are sufficient, the relay terminal device may send the second RRC request message of the remote terminal device and the first RRC request message of the relay terminal device to the network device through the RA-SDT resources or CG-SDT resources. Optionally, if the RA-SDT resources or CG-SDT resources are insufficient to send the first RRC request message of the relay terminal device and the second RRC request message of the remote terminal device, the relay terminal device may also first send the first RRC request message of the relay terminal device to the network device through the RA-SDT resources or CG-SDT resources. After the network device receives the first RRC request message, it determines that there is currently a transmission demand for small packet data based on the resource for receiving the first RRC request message. The network device can schedule the first resource for the relay terminal device, and the relay terminal device can send the second RRC request message of the remote terminal device to the network device on the first resource. It can be understood that at this time, the network device can determine that the current relay terminal device has an SDT demand based on the RA-SDT resources or CG-SDT, and determine that the SDT demand includes the SDT demand of the remote terminal device based on the second RRC request message. Optionally, the relay terminal device may also first send a first RRC request message of the relay terminal device to the network device through the RA resource. The first RRC request message may include cause information. After the network device receives the first RRC request message, it determines that there is currently a transmission demand for small packet data based on the cause information. The network device may schedule the first resource for the relay terminal device, and the relay terminal device may send a second RRC request message of the remote terminal device to the network device on the first resource. In other words, the relay terminal device may send the first RRC request message of the relay terminal device and the second RRC request message of the remote terminal device at the same time, or it may send the first RRC request message first and then send the second RRC request message of the remote terminal device.

[0263] S608: The network device sends a third RRC response message to the remote terminal device through the relay terminal device, and the remote terminal device receives the third RRC response message through the relay terminal device.

[0264] Optionally, the third RRC response message indicates that the network device confirms receipt of the second RRC request message of the remote terminal device.

[0265] Optionally, the third RRC response message may switch the remote terminal device to an RRC connected state, allowing the remote terminal device to transmit the first packet data in the RRC connected state. For example, the third RRC response message is an RRC recovery message or an RRC establishment message. The third RRC response message corresponds to the second RRC request message. For example, if the second RRC request message is an RRC recovery request message, then the third RRC response message is an RRC recovery message, i.e., the remote terminal device is in an RRC inactive state or an RRC idle state when the first packet data arrives, and the network device switches the remote terminal device from the RRC inactive state or the RRC idle state to the RRC connected state. For another example, if the second RRC request message is an RRC establishment request message, then the third RRC response message is an RRC establishment message, i.e., the remote terminal device is in an RRC idle state when the first packet data arrives, and the network device switches the remote terminal device from the RRC idle state to the RRC connected state. Optionally, the third RRC response message may also include first configuration information and / or SRAP configuration of the PC5 relay RLC channel used to transmit the packet data.

[0266] Optionally, the third RRC response message may not switch the remote terminal device to the RRC connected state, but instead maintain the remote terminal device in the RRC non-connected state, allowing the remote terminal device to transmit the first packet data in the RRC non-connected state. For example, the third RRC response message is a newly introduced message. Optionally, the third RRC response message may also include first configuration information and / or SRAP configuration for the PC5 relay RLC channel used to transmit the packet data. In other words, the third RRC response message can enable the remote terminal device to determine that the network device has received the second RRC request message. Optionally, the network device may also provide the first configuration information and / or SRAP configuration to the remote terminal device via the third RRC response message, but will not switch the remote terminal device to the RRC connected state.

[0267] Optionally, if the third RRC response message includes the first configuration information and / or SRAP configuration of the PC5 relay RLC channel for transmitting packet data, the remote terminal device can send the first configuration information and / or SRAP configuration to the relay terminal device so that the relay terminal device can receive the packet data sent by the remote terminal device according to the first configuration information and / or SRAP configuration.

[0268] Optionally, the remote terminal device may not send the first configuration information and / or SRAP configuration to the relay terminal device. In this case, the relay terminal device may use the first configuration information and / or SRAP configuration of the PC5 relay RLC channel included in the first context.

[0269] S609a, the remote terminal device sends a first packet of data to the relay terminal device, and the relay terminal device receives the first packet of data from the remote terminal device.

[0270] Optionally, the remote terminal device sending the first packet data to the relay terminal device includes: the remote terminal device sending the first packet data to the relay terminal device according to the first configuration information and / or the PC5 SRAP configuration; and the relay terminal device receiving the first packet data from the remote terminal device includes: the relay terminal device receiving the first packet data from the remote terminal device according to the first configuration information and / or the PC5 SRAP configuration. Optionally, if the third RRC response message includes the first configuration information and / or the PC5 SRAP configuration, the remote terminal device sends the first packet data using the first configuration information and / or the PC5 SRAP configuration in the third RRC response message.

[0271] Optionally, if the remote terminal device is in an RRC non-connected state (e.g., an RRC inactive state), the remote terminal device may send the first packet data to the relay terminal device based on the first configuration information of the PC5 relay RLC channel and / or the PC5 SRAP configuration corresponding to the identifier of the PC5 relay RLC channel included in the third context. Optionally, if the remote terminal device is in an RRC non-connected state (e.g., an RRC inactive state), the remote terminal device may send the first packet data to the relay terminal device based on the first configuration information and / or the PC5 SRAP configuration in the third RRC response message for keeping the remote terminal device in the RRC inactive state. Optionally, if the first packet data arrives on a certain RB of the remote terminal device, the remote terminal device may determine the identifier of the PC5 relay RLC channel corresponding to the RB based on the PC5 SRAP configuration included in the third context, and then determine the first configuration information of the PC5 relay RLC channel corresponding to the identifier of the PC5 relay RLC channel. Optionally, if the remote terminal device saves the third context and the third RRC response message that keeps the remote terminal device in the RRC non-connected state also includes the first configuration information and / or PC5 SRAP configuration, the remote terminal device can send the first packet data to the relay terminal device according to the first configuration information and / or PC5SRAP configuration in the third RRC response message.

[0272] Optionally, in S609a, the first configuration information and / or PC5 SRAP configuration used by the relay terminal device may be sent by the remote terminal device, or may be included in the first context, which is not limited in this embodiment of the present application.

[0273] Optionally, in S609a, the remote terminal device may send the first packet data to the relay terminal device through the PC5-S connection or the PC5-RRC connection according to the first configuration information and / or the PC5 SRAP configuration, and the relay terminal device may receive the first packet data from the remote terminal device through the PC5-S connection or the PC5-RRC connection according to the first configuration information and / or the PC5 SRAP configuration.

[0274] S610a, the relay terminal device sends a first packet of data to the network device, and the network device receives the first packet of data.

[0275] Optionally, the relay terminal device sends the first packet data to the network device, including: the relay terminal device sends the first packet data to the network device according to the second configuration information and / or Uu SRAP configuration; the network device receives the first packet data, including: the network device receives the first packet data according to the second configuration information and / or Uu SRAP configuration.

[0276] Optionally, the relay terminal device may send the first packet data to the network device based on the second configuration information of the Uu relay RLC channel corresponding to the identifier of the Uu relay RLC channel included in the first context. Optionally, if the relay terminal device receives the first packet data on a PC5 relay RLC channel, the relay terminal device may determine the RB corresponding to the PC5 relay RLC channel based on the PC5 SRAP configuration included in the first context, determine the identifier of the Uu relay RLC channel corresponding to the RB based on the Uu SRAP configuration, and then determine the second configuration information of the Uu relay RLC channel corresponding to the identifier of the Uu relay RLC channel.

[0277] Optionally, if the remote terminal device sends the first uplink packet data to the network device, S609a and S610a may be present. If the network device sends the first downlink packet data to the remote terminal device, S609b and S610b may be included, wherein:

[0278] S609b, the network device sends the first packet data to the relay terminal device, and the relay terminal device receives the first packet data from the network device.

[0279] Optionally, the network device sends the first packet data to the relay terminal device, including: the network device sends the first packet data to the relay terminal device according to the second configuration information and / or Uu SRAP configuration; the relay terminal device receives the first packet data from the network device, including: the relay terminal device receives the first packet data from the network device according to the second configuration information and / or Uu SRAP configuration.

[0280] Optionally, the relay terminal device may receive the first packet data from the network device based on the second configuration information of the Uu relay RLC channel corresponding to the identifier of the Uu relay RLC channel included in the first context. Optionally, if the relay terminal device receives the first packet data on a certain Uu relay RLC channel, the relay terminal device determines the RB corresponding to the Uu relay RLC channel based on the Uu SRAP configuration.

[0281] S610b: The relay terminal device sends a first packet of data to the remote terminal device, and the remote terminal device receives the first packet of data from the relay terminal device.

[0282] Optionally, the relay terminal device sends the first packet data to the remote terminal device, including: the relay terminal device sends the first packet data to the remote terminal device according to the first configuration information and / or PC5 SRAP configuration; the remote terminal device receives the first packet data from the relay terminal device, including, the remote terminal device receives the first packet data from the relay terminal device according to the first configuration information and / or PC5 SRAP configuration.

[0283] Optionally, if the relay terminal device receives the first packet data on a Uu relay RLC channel, the relay terminal device determines the RB corresponding to the Uu relay RLC channel based on the Uu SRAP configuration in the first context. The relay terminal device determines the identifier of the PC5 relay RLC channel corresponding to the RB based on the PC5 SRAP configuration in the first context, and then determines first configuration information of the PC5 relay RLC channel corresponding to the identifier of the PC5 relay RLC channel in the first context. The relay terminal device may use the first configuration information to send the first packet data to the remote terminal device.

[0284] Optionally, if the third RRC response message includes the first configuration information and / or PC5 SRAP configuration, the remote terminal device uses the first configuration information and / or PC5 SRAP configuration in the third RRC response message to receive the first packet data.

[0285] Optionally, if the remote terminal device is in an RRC non-connected state (e.g., an RRC inactive state), the remote terminal device may receive the first packet data from the relay terminal device based on the first configuration information and / or PC5 SRAP configuration of the PC5 relay RLC channel corresponding to the identifier of the PC5 relay RLC channel included in the third context. Optionally, if the remote terminal device is in an RRC non-connected state (e.g., an RRC inactive state), the remote terminal device may receive the first packet data from the relay terminal device based on the first configuration information and / or PC5 SRAP configuration in the third RRC response message that maintains the remote terminal device in the RRC non-connected state. Optionally, if the remote terminal device has saved the third context and the third RRC response message that maintains the remote terminal device in the RRC non-connected state also includes the first configuration information and / or PC5 SRAP configuration, the remote terminal device may receive the first packet data from the relay terminal device based on the first configuration information and / or PC5 SRAP configuration in the third RRC response message.

[0286] Optionally, in S610b, the first configuration information and / or PC5 SRAP configuration used by the relay terminal device may be sent by the remote terminal device, or may be included in the first context, which is not limited in this embodiment of the present application.

[0287] Optionally, in S610b, the relay terminal device may send the first packet data to the remote terminal device through the PC5-S connection or the PC5-RRC connection according to the first configuration information and / or the PC5 SRAP configuration, and the remote terminal device may receive the first packet data from the relay terminal device through the PC5-S connection or the PC5-RRC connection according to the first configuration information and / or the PC5 SRAP configuration.

[0288] Optionally, the communication method 600 may further include S611 and / or S612:

[0289] S611, the network device sends an RRC release message to the relay terminal device.

[0290] Among them, the RRC release message in S611 can be a response message to the first RRC request message of the relay terminal device in S607, that is, the network device can continue to release the relay terminal device to enter the RRC inactive state.

[0291] S612: The network device sends an RRC release message to the remote terminal device through the relay terminal device.

[0292] Optionally, the RRC release message in S612 may release the remote terminal device, and the remote terminal device enters an RRC inactive state.

[0293] In the above method 600, the network device can send an RRC release message to the relay terminal device, and the RRC release message can release the relay terminal device to the RRC inactive state. The relay terminal device can save the first context according to the third indication information and / or the suspension indication in the RRC release message. When the remote terminal device has a small packet data transmission requirement, it can determine whether the transmission conditions are met. If the transmission conditions are met, it can send an RRC request message and the first indication information to the relay terminal device. The relay terminal device can determine whether the small packet data transmission conditions are met. If they are met, it can restore the first context. The relay terminal device can use the first configuration information in the restored first context or the first configuration information received from the remote terminal device to receive the first small packet data from the remote terminal device. The relay terminal device can use the second configuration information in the restored first context to send the first small packet data of the remote terminal device to the network device in the RRC non-connected state, avoiding the need for the relay terminal device to enter the RRC connected state to send the first small packet data of the remote terminal device to the network device, thereby reducing the power consumption of the relay terminal device when entering the RRC connected state.

[0294] Optionally, if the transmission conditions for the packet data are not met in S606, the relay terminal device initiates an RRC connection recovery process and may also release the first context. For example, the relay terminal device sends an RRC recovery request message to restore the RRC connection with the network device, and uses the restored RRC connection to obtain the second context. Furthermore, the relay terminal device may use the restored RRC connection to send an RRC request message of the remote terminal device to the network device. The network device may send an RRC recovery message to the relay terminal device. The RRC recovery message may include the second context. The second context may include third configuration information of the PC5 relay RLC channel, PC5 SRAP configuration, Uu SRAP configuration, and fourth configuration information of the Uu relay RLC channel. The network device may also send an RRC response message to the remote terminal device through the relay terminal device. The RRC response message may include the third configuration information of the PC5 relay RLC channel and the PC5 SRAP configuration. The remote terminal device can send the first packet data to the relay terminal device based on the third configuration information and the PC5 SRAP configuration. The relay terminal device can receive the first packet data from the remote terminal device based on the third configuration information and the PC5 SRAP configuration. The relay terminal device can send the first packet data to the network device based on the fourth configuration information and the Uu SRAP configuration. The network device can receive the first packet data from the relay terminal device based on the fourth configuration information and the Uu SRAP configuration. Because the relay terminal device releases the first context when initiating the RRC connection recovery process, this can prevent the relay terminal device from using the saved first context, which would result in inconsistencies between the relay terminal device and the network device and affect the transmission of the first packet data.

[0295] It can be understood that the communication method 600 is described by taking the uplink transmission of the first packet data as an example. The downlink transmission of the first packet data is similar to the communication method 600 and is not described in detail to avoid redundancy.

[0296] In the above-mentioned communication methods 400 to 600, the network device may be a network device to which the relay terminal device accesses. If, as the relay terminal device moves, the relay terminal device moves from the coverage area of ​​the second network device to the coverage area of ​​the first network device, but the second network device saves the first context of the relay terminal device, the relay terminal device will be unable to send the first packet data to the first network device according to the first context. The following describes the situation in which the relay terminal device moves from the coverage area of ​​the second network device to the coverage area of ​​the first network device in conjunction with communication method 700. As shown in FIG7 , communication method 700 includes some or all of the following steps:

[0297] S701: The second network device sends a first RRC response message to the relay terminal device, and the relay terminal device receives the first RRC response message.

[0298] Optionally, the first RRC message may be an RRC release message. After receiving the RRC release message, the relay terminal device may enter an RRC inactive state.

[0299] Specifically, the description of S701 may refer to the description of S601 . That is, the network device in S601 may be the second network device in the communication method 700 .

[0300] S702, same as S602.

[0301] S703, the first network device broadcasts the second indication information, the relay terminal device and / or the remote terminal device can receive the second indication information, and the second indication information can indicate that the first network device supports the relay terminal device to transmit small packet data between the remote terminal device and the first network device in the RRC non-connected state.

[0302] Specifically, the description of S703 may refer to the description of S603 , that is, the network device in S603 may be the first network device in the communication method 700 .

[0303] S704-S706 are the same as S604-S606 respectively.

[0304] S707, the relay terminal device can send a first RRC request message of the relay terminal device and a second RRC request message of the remote terminal device to the first network device, and the first network device can receive the first RRC request message of the relay terminal device and the second RRC request message of the remote terminal device from the relay terminal device.

[0305] For S707 , reference may be made to the description of S607 , wherein the network device in S607 may be the first network device in S707 .

[0306] S708, the first network device may send fifth indication information to the second network device, and the second network device may receive the fifth indication information from the first network device, where the fifth indication information is used to request the relay terminal device to transmit the first context of the packet data of the remote terminal device.

[0307] Optionally, the first network device may determine that the relay terminal device has an SDT requirement based on the cause information in S707 and / or may determine that the relay terminal device has an SDT requirement based on the resource used by the relay terminal device to send the first RRC request message. Therefore, the first network device may execute S708. For example, if the first network device determines that the relay terminal device has an SDT requirement based on the cause information in S707, and the first network device also receives a second RRC request message, the first network device may determine that the recovery process currently initiated by the relay terminal device is for small packet data transmission of the remote terminal device, and therefore the first network device sends a fifth indication information request related context to the second network device, thereby ensuring small packet data transmission of the remote terminal device. For another example, if the first network device determines that the relay terminal device has an SDT requirement based on the cause information in S707, and the cause information indicates that the remote terminal device has an SDT requirement, the first network device may determine that the recovery process currently initiated by the relay terminal device is for small packet data transmission of the remote terminal device, and therefore the first network device sends a fifth indication information request related context to the second network device, thereby ensuring small packet data transmission of the remote terminal device. For another example, the first network device determines that the relay terminal device has an SDT requirement based on the resources used by the relay terminal device in S707 to send the first RRC request message, and the first network device also receives the second RRC request message. The first network device can then determine that the recovery process initiated by the current relay terminal device is for the transmission of small packet data of the remote terminal device. Therefore, the first network device sends the fifth indication information request related context to the second network device, thereby ensuring the transmission of small packet data of the remote terminal device.

[0308] Optionally, S708 includes: the first network device sending a first Xn interface request message to the second network device, where the first Xn interface request message may include fifth indication information. For example, the first Xn interface request message may be a RETRIEVE UE CONTEXT REQUEST message.

[0309] Optionally, in addition to being used to request the relay terminal device to transmit the first context of the packet data of the remote terminal device, the fifth indication information can also be used to request the relay terminal device to execute a relay-related context, wherein the execution of the relay-related context includes both the first context and the context of the relay terminal device transmitting the non-packet data of the remote terminal device.

[0310] S709: The second network device sends the first context to the first network device, and the first network device receives the first context from the second network device.

[0311] Optionally, S709 includes: the second network device may send a first Xn interface response message to the first network device. The first Xn interface response message may be a response message to the first Xn interface request message, for example, the first Xn interface response message may be a RETRIEVE UE CONTEXT RESPONSE message or a PARTIAL UE CONTEXT TRANSFER message.

[0312] Optionally, the second network device may determine whether to replace the anchor base station for the relay terminal device. If the second network device determines to replace the anchor base station for the relay terminal device, then in S709, the second network device may send the entire context of the relay terminal device to the first network device. For example, the entire context may include the Uu-related context and the relay-related context of the relay terminal device. For example, the second network device may include the entire context of the relay terminal device in the first Xn interface response message. Optionally, if the second network device determines not to replace the anchor base station for the relay terminal device, then in S709, the second network device may send a partial context of the relay terminal device to the first network device. The partial context may include the first context and / or the configuration information of the Uu RLC channel. For example, the second network device may include the partial context of the relay terminal device in the first Xn interface response message.

[0313] S710, the first network device may send sixth indication information to the second network device, and the second network device may receive the sixth indication information from the first network device, where the sixth indication information is used to request a third context related to the packet data from the remote terminal device.

[0314] Optionally, S710 includes: the first network device sending a second Xn interface request message to the second network device, where the second Xn interface request message may include sixth indication information. For example, the second Xn interface request message may be a RETRIEVE UE CONTEXT REQUEST message.

[0315] S711: The second network device sends a third context to the first network device, and the first network device receives the third context from the second network device.

[0316] Optionally, S711 includes: the second network device may send a second Xn interface response message to the first network device. The second Xn interface response message may be a response message to the second Xn interface request message, for example, the second Xn interface response message may be a RETRIEVE UE CONTEXT RESPONSE message or a PARTIAL UE CONTEXT TRANSFER message.

[0317] Optionally, in some cases, the first network device can obtain the third context related to the packet data of the remote terminal device and the first context of the relay terminal device through an indication message. At this time, S708 and S710 are one step. For example, the first Xn interface request message in S708 and the second Xn interface request message in S710 can be the same Xn interface request message, and the Xn interface request message includes an indication message. The second network device can send the first context of the relay terminal device and the third context of the remote terminal device to the first network device after receiving the indication message. Optionally, the second network device can also send the Uu-related context of the remote terminal device to the first network device at the same time after receiving the indication message. In this case, S709 and S711 can be a single step. The second network device can send the first context of the relay terminal device and / or the Uu-related context of the relay terminal device, as well as the third context of the remote terminal device and / or the Uu-related context of the remote terminal device, to the first network device. For example, the second network device can send an Xn interface response message to the first network device. The Xn interface response message can include the first context of the relay terminal device and / or the Uu-related context of the relay terminal device, as well as the third context of the remote terminal device and / or the Uu-related context of the remote terminal device. This avoids the first network device from separately requesting the context of the relay terminal device and the remote terminal device from the second network device. Optionally, the first network device can directly request the context of the relay terminal device and the context of one or more remote terminal devices connected to the relay terminal device via the first indication information. Based on the indication information, the second network device can send the context of the relay terminal device and the context of the one or more remote terminal devices connected to the relay terminal device to the first network device, thereby reducing the signaling interaction process between the first and second network devices.

[0318] Optionally, in some cases, S710 and S711 may not exist, that is, S710 and S711 are optional steps, that is, the third context of the remote terminal device obtained by S711 is for the remote terminal device to send the first packet data to the first network device in the RRC non-connected state. If the remote terminal device sends the first packet data to the first network device in the RRC connected state, the first network device may not need to obtain the third context.

[0319] Optionally, after S711, S712 may be executed.

[0320] S712: The first network device sends a third RRC response message to the remote terminal device through the relay terminal device, and the remote terminal device receives the third RRC response message through the relay terminal device.

[0321] For S712 , reference may be made to the description of S608 , wherein the network device in S608 may be the first network device in S712 .

[0322] S713a, same as S609a.

[0323] S714a, the relay terminal device sends a first packet of data to the first network device, and the first network device receives the first packet of data.

[0324] For S714a , reference may be made to the description of S610a , wherein the network device in S610a may be the first network device in S714a .

[0325] Optionally, if the first network device receives the entire context of the relay terminal device from the second network device, it indicates that the mapping base station is changed. After the first network device receives the first packet data from the relay terminal device in S714a, it may not send the first packet data to the second network device.

[0326] Optionally, if the first network device receives a partial context of the relay terminal device from the second network device, it means that the mapping base station will not be changed. After the first network device receives the first packet data from the relay terminal device in S714a, it can send the first packet data to the second network device.

[0327] S713b, the first network device sends the first packet data to the relay terminal device, and the relay terminal device receives the first packet data from the first network device.

[0328] For S713b, reference may be made to the description of S609b, wherein the network device in S609b may be the first network device in S713b.

[0329] S714b, same as S610b.

[0330] S715. The first network device sends an RRC release message to the relay terminal device.

[0331] For S715 , reference may be made to the description of S611 , wherein the network device in S611 may be the first network device in S715 .

[0332] S716: The first network device sends an RRC release message to the remote terminal device through the relay terminal device.

[0333] For S716 , reference may be made to the description of S612 , wherein the network device in S612 may be the first network device in S716 .

[0334] Optionally, in the communication method 700, the first network device may be a target network device or a target base station, and the second network device may be a source network device or a source base station.

[0335] In the aforementioned communication method 700, after the relay terminal device moves from the coverage area of ​​the second network device to the coverage area of ​​the first network device, the first network device may obtain the first context of the relay terminal device and / or the third context of the remote terminal device from the second network device. The first context and the third context are contexts used to transmit packet data of the remote terminal device. In this way, the relay terminal device can transmit packet data between the remote terminal device and the first network device even within the coverage area of ​​the first network device.

[0336] In some scenarios, if the relay terminal device is transmitting the second packet data of the relay terminal device in the RRC non-connected state or the relay terminal device is transmitting the first packet data of the remote terminal device in the RRC non-connected state, and non-packet data arrives, the relay terminal device may enter the RRC connected state to transmit the arrived non-packet data. The following is described in conjunction with the communication method 800. As shown in Figure 8, the communication method 800 includes some or all of the following steps:

[0337] S810, when the relay terminal device is performing transmission of packet data in the RRC non-connected state, first non-packet data arrives, the relay terminal device sends seventh indication information to the network device, and the network device receives the seventh indication information from the relay terminal device, where the seventh indication information is used to indicate that there is a need for non-packet data transmission.

[0338] Alternatively, the seventh indication information indicates the arrival of non-small packet data, or indicates that the relay terminal device requests to enter the RRC connection state, or indicates that data has arrived on a non-SDT RB, etc.

[0339] Optionally, S810 includes: the relay terminal device sends seventh indication information to the network device during the transmission of packet data of the relay terminal device in the RRC non-connected state.

[0340] Optionally, S810 includes: the relay terminal device sends seventh indication information to the network device during the transmission of packet data of a second remote terminal device connected to the relay terminal device in the RRC non-connected state. For example, the remote terminal device in the above communication methods 400 to 700 can be the second remote terminal device.

[0341] Optionally, the first non-packet data may include non-packet data of the relay terminal device. That is, when the relay terminal device is transmitting packet data of the relay terminal device in an RRC non-connected state or transmitting packet data of a second remote terminal device connected to the relay terminal device, first non-packet data of the relay terminal device arrives, and the relay terminal device may execute S810. For example, the first non-packet data may be data of a non-SDT RB of the relay terminal device.

[0342] Optionally, the first non-packet data may include non-packet data of a first remote terminal device connected to the relay terminal device. That is, during the process of transmitting packet data of the relay terminal device or transmitting packet data of a second remote terminal device connected to the relay terminal device in an RRC unconnected state, non-packet data of the first remote terminal device connected to the relay terminal device arrives. Since the relay terminal device cannot transmit non-packet data during packet transmission, S810 may be executed. For example, the first remote terminal device may indicate the arrival of non-packet data or the amount of non-packet data to the relay terminal device. Based on the indication, the relay terminal device determines that non-packet data has arrived at the first remote terminal device, and thus S810 may be executed. Alternatively, the first remote terminal device may send the non-packet data of the first remote terminal device to the relay terminal device. The relay terminal device may determine that non-packet data has arrived at the first remote terminal device, and thus S810 may be executed. For another example, if the first non-packet data is data in a non-SDT RB, and the relay terminal device receives the data on the PC5 relay RLC channel corresponding to the non-SDT RB of the first remote terminal device, the relay terminal device determines that the data currently arriving at the first remote terminal device is non-SDT data, and therefore can execute S810. Optionally, the first remote terminal device and the second remote terminal device can be the same or different.

[0343] Optionally, the first non-packet data may include packet data of one or more remote terminal devices connected to the relay terminal device, that is, if the packet data of multiple remote terminal devices need to be transmitted by the relay terminal device, due to the large amount of data, the relay terminal device may enter the RRC connection state to transmit the packet data for multiple remote terminal devices, or if the amount of packet data of a remote terminal device is large, the relay terminal device may also enter the RRC connection state to transmit the packet data for the remote terminal device. For example, when the relay terminal device is in the process of transmitting the packet data of the relay terminal device in the RRC non-connection state or in the process of transmitting the packet data of the second remote terminal device connected to the relay terminal device, packet data of other remote terminal devices arrives, and therefore, S810 may be executed, for example, the other remote terminal devices include the first remote terminal device and / or the third remote terminal device. For another example, when the relay terminal device is transmitting packet data of the relay terminal device in the RRC unconnected state or transmitting packet data of a second remote terminal device connected to the relay terminal device, packet data of the second remote terminal device arrives, and therefore S810 may be executed. Optionally, the remote terminal device may indicate the amount of non-packet data to the relay terminal device, indicate the arrival of non-packet data, or send non-packet data of multiple remote terminal devices to the relay terminal device.

[0344] Optionally, S810 includes: the relay terminal device may send an RRC recovery request message to the network device, and the RRC recovery request message may include seventh indication information. Optionally, the seventh indication information may be included in a UE assistance information (UEAssistanceInformation) message.

[0345] Optionally, the data size of the first non-small packet data is greater than or equal to a preset value, for example, the preset value may be 500 bytes or 300 bytes, etc. Optionally, the first non-small packet data is data on a non-SDT RB.

[0346] S820, the relay terminal device enters the RRC connection state to transmit the first non-packet data.

[0347] Optionally, after S810, the network device may send an RRC recovery message to the relay terminal device, and the relay terminal device may use the RRC recovery message to enter an RRC connection state to transmit the first non-packet data.

[0348] In the above-mentioned communication method 800, when the relay terminal device is transmitting small packet data in the RRC non-connected state, when non-small packet data arrives, it can send the seventh indication information to the network device to indicate the transmission requirement of the non-small packet data, and the relay terminal device can enter the RRC connected state to transmit the small packet data, thereby providing a method for transmitting non-small packet data during the transmission of small packet data, avoiding the problem of being unable to transmit non-small packet data.

[0349] It is understandable that the above communication methods can be combined with each other. For example, the first network device in the above communication method 700 can be the network device in the communication method 400-communication method 600 or communication method 800.

[0350] It can be understood that in the embodiment of the present application, when the remote terminal device or the relay terminal device is in the RRC non-connected state, the RRC connection is restored to perform SDT. For the convenience of description, the remote terminal device or the relay terminal device initiates the RRC connection recovery process as an example, and it is not limited to the remote terminal device or the relay terminal device executing the recovery process.

[0351] In an embodiment of the present application, the packet data transmission process may be a packet data transmission process in an RRC non-connected state.

[0352] The above describes the method embodiments provided by this application, and the following describes the device embodiments provided by this application. It should be understood that the description of the device embodiments corresponds to the description of the method embodiments. Therefore, for matters not described in detail, reference can be made to the method embodiments above. For the sake of brevity, they will not be repeated here.

[0353] Figure 9 is a schematic block diagram of a communication device provided in an embodiment of the present application. As shown in Figure 9, the communication device 900 may include a processing unit 910 and a communication unit 920. The communication unit 920 can implement corresponding communication functions, and the communication can be internal communication of the communication device 900 or communication between the communication device 900 and other devices; the processing unit 910 can implement corresponding processing functions. The communication unit 920 can also be called a communication interface or a transceiver unit. Optionally, the communication device 900 may also include a storage unit, which can be used to store instructions and / or data, and the processing unit 910 can read the instructions and / or data in the storage unit so that the device implements the aforementioned method embodiment.

[0354] In one possible design, the communication device 900 may be the relay terminal device in methods 400, 500, and 600 described above, or may be a module or chip applied to the relay terminal device. Methods 400, 500, and 600 may be used to execute the steps or processes executed by the relay terminal device in the above-described embodiments.

[0355] Specifically, the processing unit 910 is used to save a first context for transmitting packet data between a remote terminal device and a network device; if the transmission conditions of the packet data are met, the first context is restored; and the communication unit 920 is used to transmit the first packet data between the remote terminal device and the network device in an RRC non-connected state based on the restored first context.

[0356] Optionally, the transmission condition includes at least one of the following: the RRC layer of the communication device 900 triggers the RRC connection recovery process, the amount of data related to the packet data transmission is less than or equal to the first data amount threshold value, the reference signal received power RSRP between the remote terminal device and the communication device 900 is greater than or equal to the first RSRP threshold value, the Uu reference signal received power RSRP of the communication device 900 is greater than or equal to the second RSRP threshold value, or the first indication information of the remote terminal device is received, and the first indication information is used to indicate that the remote terminal device has a transmission requirement for small packet data, or the second indication information sent by the network device is received, and the second indication information indicates that the network device supports the communication device 900 to transmit the small packet data between the remote terminal device and the network device in the RRC non-connected state.

[0357] Optionally, the amount of data related to packet data transmission includes at least one of the size of the first packet data, the size of the second packet data of the communication device 900, and the size of the RRC request message from the remote terminal device.

[0358] Optionally, the communication unit 920 is further used to: receive data volume information from the remote terminal device, where the data volume information is used to indicate the size of the first packet data.

[0359] Optionally, the first indication information is included in information of a media access control MAC layer; or, the first indication information is included in information of an SRAP layer.

[0360] Optionally, the information of the MAC layer is a MAC control element CE or a MAC subheader, or the information of the SRAP layer is a SRAP subheader or a SRAP protocol data unit PDU.

[0361] Optionally, the communication unit 920 is further configured to: receive third indication information, where the third indication information indicates at least one of the following:

[0362] An identifier of a Uu relay radio link control RLC channel used to transmit packet data of the remote terminal device, or an identifier of a Uu relay RLC channel used for packet data transmission SDT of the remote terminal device, or an identifier of a Uu relay RLC channel used for SDT radio bearer RB of the remote terminal device;

[0363] An identifier of a PC5 relay RLC channel used for transmitting packet data of the remote terminal device, or an identifier of a PC5 relay RLC channel used for the SDT of the remote terminal device, or an identifier of a PC5 relay RLC channel used for the SDT RB of the remote terminal device;

[0364] The identifier of the radio bearer RB of the remote terminal device used to transmit packet data, the identifier of the RB corresponds to the identifier of the Uu relay RLC channel and the identifier of the PC5 relay RLC channel.

[0365] Optionally, the processing unit 910 is specifically configured to: save a first context for transmitting packet data between the remote terminal device and the network device based on the third indication information.

[0366] Optionally, the first context includes first configuration information of the PC5 relay RLC channel corresponding to the identifier of the PC5 relay RLC channel, second configuration information of the Uu relay RLC channel corresponding to the identifier of the Uu relay RLC channel, PC5 sidelink relay adaptation protocol SRAP configuration, Uu SRAP configuration or at least one of the third indication information.

[0367] Optionally, the first context includes: the second configuration information of the RLC channel corresponding to the identifier of the Uu relay RLC channel, the PC5 sidelink relay adaptation protocol SRAP configuration, the Uu SRAP configuration or at least one of the third indication information, and the communication unit 920 is also used to: receive the first configuration information of the RLC channel corresponding to the identifier of the PC5 relay RLC channel from the remote terminal device.

[0368] Optionally, the communication unit 920 is specifically used to: receive the first packet data from the remote terminal device based on the first configuration information; and send the first packet data to the network device based on the second configuration information.

[0369] Optionally, the communication unit 920 is specifically used to: receive first packet data from the network device based on the second configuration information; and send the first packet data to a remote terminal device based on the first configuration information.

[0370] Optionally, the processing unit 910 is further configured to: if the transmission condition of the packet is not met, the communication device 900 requests to enter the RRC connected state, release the first context, and obtain a second context;

[0371] Optionally, the communication unit 920 is specifically used to: transmit the first packet data between the remote terminal device and the network device in the RRC connection state based on the second context.

[0372] Optionally, the remote terminal device is in an RRC connected state, an RRC idle state or an RRC inactive state.

[0373] Optionally, the communication unit 920 is also used to: receive first timer information from the network device, the first timer information being used to indicate the first duration of the first timer for the communication device 900 to transmit the packet data between the remote terminal device and the network device in the RRC non-connected state; wherein the communication unit 920 is specifically used to: transmit the first packet data between the remote terminal device and the network device in the RRC non-connected state within the first duration.

[0374] In one possible design, the communication device 900 may be the remote terminal device described in methods 400, 500, and 600 above, or may be a module or chip applied to the remote terminal device. Methods 400, 500, and 600 may be used to execute the steps or processes performed by the remote terminal device in the above embodiments.

[0375] Specifically, the processing unit 910 is configured to: when there is a small packet data transmission demand, determine whether the conditions for small packet transmission are met;

[0376] The communication unit 920 is used to send first indication information to the relay terminal device if the transmission conditions of the packet data are met, and the first indication information is used to indicate the packet data transmission requirements of the communication device 900.

[0377] Optionally, the transmission condition includes at least one of the following: the communication unit 920 receives second indication information sent by the network device, where the second indication information is used to indicate that the network device supports the relay terminal device to transmit small packet data between the communication device 900 and the network device in a radio resource control RRC non-connected state;

[0378] The relay terminal device currently connected to the communication device 900 and the relay terminal device that forwards the RRC message from the network device to the communication device 900 are the same terminal device;

[0379] The reference signal received power RSRP between the communication device 900 and the relay terminal device is greater than a second RSRP threshold value;

[0380] The data volume of the first packet data is less than or equal to the second data volume threshold.

[0381] Optionally, the data volume of the first packet data includes: the size of the PC5 radio link control RLC protocol data unit PDU corresponding to the first packet data and / or the size of the PC5 RLC service data unit SDU corresponding to the first packet data.

[0382] Optionally, the first indication information is included in information of a media access control MAC layer; or, the first indication information is included in information of an SRAP layer.

[0383] Optionally, the information of the MAC layer is a MAC control element CE or a MAC subheader, or the information of the SRAP layer is a SRAP subheader or a SRAP protocol data unit PDU.

[0384] Optionally, the communication unit 920 is used to: receive first configuration information of a PC5 relay radio link control RLC channel from a network device through the relay terminal device; and send the first configuration information of the PC5 relay RLC channel to the relay terminal device.

[0385] Optionally, the communication device 900 is in an RRC connected state, an RRC idle state or an RRC inactive state.

[0386] In one possible design, the communication apparatus 900 may be the first network device in the communication method 700 described above, or may be a module or chip applied to the first network device. The communication method 700 may be used to execute the steps or processes executed by the first network device in the above embodiments.

[0387] Specifically, the communication unit 920 is configured to send fifth indication information to the second network device, where the fifth indication information is used to request the relay terminal device to transmit the first context of the packet data of the remote terminal device;

[0388] The communication unit 920 is further configured to transmit the first packet data of the remote terminal device through the relay terminal device based on the first context.

[0389] Optionally, the communication unit 920 is also used to send a sixth indication message to the second network device, wherein the sixth indication message is used to request a third context related to packet data of a remote terminal device, and the remote terminal device is connected to the relay terminal device; and the first packet data of the remote terminal device is transmitted through the relay terminal device based on the third context.

[0390] Optionally, the fifth indication information and the sixth indication information are the same indication information, or the fifth indication information and the sixth indication information are different indication information.

[0391] In one possible design, the communication device 900 may be the relay terminal device in the above communication method 800, or may be a module or chip applied to the relay terminal device. The communication method 800 may be used to execute the steps or processes executed by the relay terminal device in the above embodiments.

[0392] Specifically, the communication unit 920 is used to send a seventh indication message to the network device during the transmission of packet data in the RRC non-connected state, and the seventh indication message is used to indicate that there is a need for non-packet data transmission; and enter the wireless resource control RRC connected state to transmit the first non-packet data.

[0393] Optionally, the communication unit 920 is specifically used to send a terminal device auxiliary information message to the network device, where the terminal device auxiliary information message includes the seventh indication information.

[0394] In some possible implementations, the first non-packet data is non-packet data of a first remote terminal device connected to the communication apparatus 900; or,

[0395] The first non-packet data includes non-packet data of the communication device 900; or,

[0396] The first non-packet data includes packet data of one or more remote terminal devices connected to the communication apparatus 900 .

[0397] In some possible implementations, the communication unit 920 is specifically configured to: send the seventh indication information to the network device during the transmission of the packet data of the communication apparatus 900 in the RRC non-connected state; or,

[0398] Sending the seventh indication information to the network device during the packet transmission of the second remote terminal device connected to the communication apparatus 900 in the RRC non-connected state;

[0399] The first remote terminal device and the second remote terminal device are the same terminal device or different terminal devices.

[0400] Regarding the steps or processes executed by each unit in the communication device 900, please refer to the above method embodiments for details, which will not be described in detail here.

[0401] It should be understood that the "unit" in the communication device 900 can be implemented by hardware, can be implemented by software, and can also be implemented by hardware executing the corresponding software implementation. For example, the "unit" can refer to an application specific integrated circuit (ASIC), an electronic circuit, a processor (such as a shared processor, a dedicated processor or a group processor, etc.) and a memory for executing one or more software or firmware programs, a combined logic circuit and / or other suitable components that support the described functions. For another example, the communication unit 920 can be replaced by a transceiver transceiver circuit (for example, a receiving circuit and a transmitting circuit), and the processing unit 910 can be replaced by a processor or a processing circuit.

[0402] Figure 10 shows a schematic block diagram of another communication device 1000 provided in an embodiment of the present application. The device 1000 can be a relay terminal device, a remote terminal device, or a first network device, or can be a chip, a chip system, or a processor that supports the relay terminal device, the remote device, or the first network device to implement the above method. The device can be used to implement the method described in the above method embodiment. For details, please refer to the description of the above method embodiment.

[0403] The device 1000 may include one or more processors 1010, which may also be referred to as processing units, and may implement certain control functions. The processor 1010 may be a general-purpose processor or a dedicated processor. For example, it may be a baseband processor or a central processing unit. The baseband processor may be used to process communication protocols and communication data, and the central processing unit may be used to control a communication device (e.g., a base station, a baseband chip, a user chip, a DU or a CU, etc.), execute software programs, and process data from the software programs.

[0404] In an optional design, the processor 1010 may also store instructions and / or data, which can be executed by the processor 1010 to enable the apparatus 1000 to perform the method described in the above method embodiment. Optionally, the processing unit 910 in the communication apparatus 900 may be the processor 1010.

[0405] In another optional design, the device 1000 may include a communication interface 1020 for implementing receiving and transmitting functions. For example, the communication interface 1020 may be a transceiver circuit, an interface, an interface circuit, or a transceiver. The transceiver circuit, interface, interface circuit, or transceiver for implementing the receiving and transmitting functions may be separate or integrated. The transceiver circuit, interface, interface circuit, or transceiver may be used for reading and writing code / data, or the transceiver circuit, interface, interface circuit, or transceiver may be used for transmitting or delivering signals. Optionally, the communication unit 920 in the communication device 900 may be the communication interface 1020.

[0406] Optionally, the device 1000 may include one or more memories 1030, which may store instructions that can be executed on the processor 1010, causing the device 1000 to perform the method described in the above method embodiment. Optionally, the memory 1030 may also store data. Optionally, the processor 1010 may also store instructions and / or data. The processor 1010 and the memory 1030 may be provided separately or integrated together.

[0407] Those skilled in the art will appreciate that, for ease of explanation, FIG10 illustrates only one memory and processor. In an actual relay terminal device, remote terminal device, or first network device, multiple processors and memories may exist. A memory may also be referred to as a storage medium or storage device, etc., which is not limited in this embodiment of the present application.

[0408] For example, a processor may include a baseband processor and a central processing unit (CPU). The baseband processor is primarily responsible for processing communication protocols and communication data, while the CPU is primarily responsible for controlling the entire terminal device, executing software programs, and processing data from software programs. The processor in Figure 10 integrates the functions of both the baseband processor and the CPU. Those skilled in the art will appreciate that the baseband processor and the CPU may also be independent processors interconnected via a bus or other technology. Those skilled in the art will appreciate that a terminal device may include multiple baseband processors to accommodate different network standards, multiple CPUs to enhance its processing capabilities, and that the various components of the terminal device may be connected via various buses. The baseband processor may also be referred to as a baseband processing circuit or a baseband processing chip. The CPU may also be referred to as a central processing circuit or a central processing chip. The functionality for processing communication protocols and communication data may be built into the processor or stored as a software program in a storage unit, with the processor executing the software program to implement the baseband processing functionality.

[0409] It should be understood that, in one possible design, each step in the method embodiment provided in the present application can be completed by an integrated logic circuit of the hardware in the processor or by instructions in the form of software. The steps of the method disclosed in conjunction with the embodiments of the present application can be directly embodied as being executed by a hardware processor, or can be executed by a combination of hardware and software modules in the processor. The software module can be located in a storage medium mature in the art, such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware. To avoid repetition, it will not be described in detail here.

[0410] It should be noted that the processor in the embodiments of the present application can be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiment can be completed by an integrated logic circuit of the hardware in the processor or by instructions in the form of software. The above processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component. The various methods, steps, and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in the embodiments of the present application can be directly embodied as being executed by a hardware decoding processor, or can be executed by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium mature in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, or electrically erasable programmable memory, registers, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0411] It is understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is 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), synchronous link DRAM (SLDRAM), and direct RAM bus RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0412] The present application also provides a computer program product, which includes: computer program code, which, when executed on a computer, enables the computer to execute the various steps or processes executed by the relay terminal device, the remote terminal device, or the first network device in any of the above method embodiments.

[0413] The present application also provides a computer-readable storage medium, which stores program code. When the program code runs on a computer, the computer executes the various steps or processes executed by the relay terminal device or the remote terminal device or the first network device in any of the above method embodiments.

[0414] The present application also provides a communication device, including a processor and an interface, which is used to send and / or receive signals, so that the processor executes the various steps or processes performed by the relay terminal device or the remote terminal device or the first network device in any of the above method embodiments.

[0415] The present application also provides a communication system, which includes at least two of a remote terminal device, a relay terminal device or a first network device.

[0416] The above-mentioned device embodiments and method embodiments are completely corresponding, and the corresponding steps are performed by the corresponding modules or units. For example, the communication unit or communication interface performs the receiving or sending steps in the method embodiment. Other steps except sending and receiving can be performed by the processing unit or processor.

[0417] In the embodiments of this application, each term and English abbreviation is provided for convenience of description and shall not constitute any limitation to this application. This application does not exclude the possibility of defining other terms that can achieve the same or similar functions in existing or future agreements.

[0418] As used in this specification, the terms "component," "module," "system," and the like are used to represent computer-related entities, hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, an execution thread, a program, and / or a computer. By way of illustration, both an application running on a computing device and a computing device can be a component. One or more components can reside in a process and / or an execution thread, and a component can be located on one computer and / or distributed between two or more computers. In addition, these components can be executed from various computer-readable storage media having various data structures stored thereon. Components can communicate, for example, via local and / or remote processes based on signals having one or more data packets (e.g., data from two components interacting with another component between a local system, a distributed system, and / or a network, such as the Internet interacting with other systems via signals).

[0419] Those skilled in the art will appreciate that the various illustrative logical blocks and steps described in conjunction with the embodiments disclosed herein can be implemented using electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0420] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can be based on the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0421] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0422] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0423] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0424] In the above embodiments, the functions of each functional unit can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When software is used for implementation, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions (programs). When the computer program instructions (programs) are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can 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 instructions can be transmitted from a website, computer, server or data center to another website, computer, server or data center by wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrations. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state disk (SSD)).

[0425] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0426] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A communication method, characterized in that: Applicable to relay terminal equipment, including: storing a first context for transmitting packet data between a remote terminal device and a network device; If the transmission condition of the packet data is met, restoring the first context; The first packet data between the remote terminal device and the network device is transmitted in an RRC non-connected state based on the restored first context.

2. The communication method according to claim 1, characterized in that: The transmission condition includes at least one of the following: the RRC layer of the relay terminal device triggers the RRC connection recovery process, the amount of data related to the transmission of small packet data is less than or equal to the first data amount threshold value, the reference signal received power RSRP between the remote terminal device and the relay terminal device is greater than or equal to the first RSRP threshold value, the Uu reference signal received power RSRP of the relay terminal device is greater than or equal to the second RSRP threshold value, or the first indication information of the remote terminal device is received, and the first indication information is used to indicate that the remote terminal device has a transmission requirement for small packet data, or the second indication information sent by the network device is received, and the second indication information indicates that the network device supports the relay terminal device to transmit the small packet data between the remote terminal device and the network device in the RRC non-connected state.

3. The communication method according to claim 2, characterized in that: The data volume associated with packet data transmission includes at least one of the size of the first packet data, the size of the second packet data of the relay terminal device, and the size of the RRC request message from the remote terminal device.

4. The communication method according to claim 2 or 3, characterized in that: The communication method further comprises: Data volume information is received from the remote terminal device, where the data volume information is used to indicate the size of the first packet data.

5. The communication method according to any one of claims 2 to 4, characterized in that: The first indication information is included in information of a media access control MAC layer; or, the first indication information is included in information of a SRAP layer.

6. The communication method according to claim 5, characterized in that: The information of the MAC layer is a MAC control element CE or a MAC subheader, or the information of the SRAP layer is a SRAP subheader or a SRAP protocol data unit PDU.

7. The communication method according to any one of claims 1 to 6, characterized in that: The communication method further comprises: Receive third indication information, where the third indication information indicates at least one of the following: An identifier of a Uu relay radio link control RLC channel used to transmit packet data of the remote terminal device, or an identifier of a Uu relay RLC channel used for packet data transmission SDT of the remote terminal device, or an identifier of a Uu relay RLC channel used for SDT radio bearer RB of the remote terminal device; An identifier of a PC5 relay RLC channel used to transmit packet data of the remote terminal device, or an identifier of a PC5 relay RLC channel of an SDT of the remote terminal device, or an identifier of a PC5 relay RLC channel of an SDT RB of the remote terminal device; The identifier of the radio bearer RB of the remote terminal device used to transmit packet data, the identifier of the RB corresponds to the identifier of the Uu relay RLC channel and the identifier of the PC5 relay RLC channel.

8. The communication method according to claim 7, characterized in that: The storing of the first context for transmitting packet data between the remote terminal device and the network device includes: A first context for transmitting packet data between the remote terminal device and the network device is saved based on the third indication information.

9. The communication method according to claim 7 or 8, characterized in that: The first context includes the first configuration information of the PC5 relay RLC channel corresponding to the identifier of the PC5 relay RLC channel, the second configuration information of the Uu relay RLC channel corresponding to the identifier of the Uu relay RLC channel, the PC5 sidelink relay adaptation protocol SRAP configuration, the Uu SRAP configuration or at least one of the third indication information.

10. The communication method according to claim 7 or 8, characterized in that: The first context includes: second configuration information of the RLC channel corresponding to the identifier of the Uu relay RLC channel, PC5 sidelink relay adaptation protocol SRAP configuration, Uu SRAP configuration or at least one of the third indication information, and the communication method further includes: Receive first configuration information of the RLC channel corresponding to the identifier of the PC5 relay RLC channel from the remote terminal device.

11. The communication method according to claim 9 or 10, characterized in that: The first small packet data transmitted between the remote terminal device and the network device in an RRC non-connected state based on the restored first context includes: Receiving the first packet data from the remote terminal device based on the first configuration information; The method of sending the first packet data to the network device based on the second configuration information; or transmitting the first packet data between the remote terminal device and the network device in an RRC non-connected state based on the restored first context, includes: Receiving first packet data from the network device based on the second configuration information; The first packet data is sent to a remote terminal device based on the first configuration information.

12. The communication method according to any one of claims 1 to 10, characterized in that: The communication method further comprises: If the transmission condition of the small packet is not met, the relay terminal device requests to enter the RRC connected state, releases the first context, and obtains the second context; The first packet data between the remote terminal device and the network device is transmitted in the RRC connection state based on the second context.

13. The communication method according to any one of claims 1 to 12, characterized in that: The remote terminal device is in RRC connected state, RRC idle state or RRC inactive state.

14. The communication method according to any one of claims 1 to 13, characterized in that: The communication method further comprises: Receive first timer information from the network device, where the first timer information is used to indicate a first duration of a first timer for transmitting packet data between the remote terminal device and the network device in an RRC non-connected state by the relay terminal device; The transmitting of the first packet data between the remote terminal device and the network device in an RRC non-connected state based on the restored first context includes: The first packet data between the remote terminal device and the network device is transmitted in an RRC non-connected state within the first time period based on the restored first context.

15. A communication method, characterized in that: Applied to remote terminal equipment, including: When there is a need to transmit small packet data, determine whether the conditions for small packet transmission are met; If the transmission conditions for the small packet data are met, first indication information is sent to the relay terminal device, where the first indication information is used to indicate the small packet data transmission requirements of the remote terminal device.

16. The communication method according to claim 15, characterized in that: The transmission condition includes at least one of the following: receiving second indication information sent by the network device, where the second indication information is used to indicate that the network device supports the relay terminal device to transmit small packet data between the remote terminal device and the network device in a radio resource control RRC non-connected state; The relay terminal device to which the remote terminal device is currently connected and the relay terminal device that forwards the RRC message from the network device to the remote device are the same terminal device; A reference signal received power RSRP between the remote terminal device and the relay terminal device is greater than a second RSRP threshold value; The data volume of the first packet data of the remote terminal device is less than or equal to the second data volume threshold.

17. The communication method according to claim 16, characterized in that: The data volume of the first packet data includes: the size of the PC5 radio link control RLC protocol data unit PDU corresponding to the first packet data and / or the size of the PC5 RLC service data unit SDU corresponding to the first packet data.

18. The communication method according to any one of claims 15 to 17, characterized in that: The first indication information is included in information of a media access control MAC layer; or, the first indication information is included in information of a SRAP layer.

19. The communication method according to claim 18, characterized in that: The information of the MAC layer is a MAC control element CE or a MAC subheader, or the information of the SRAP layer is a SRAP subheader or a SRAP protocol data unit PDU.

20. The communication method according to any one of claims 15 to 18, characterized in that: The communication method further comprises: Receiving first configuration information of a PC5 relay radio link control RLC channel from a network device through the relay terminal device; Sending first configuration information of the PC5 relay RLC channel to the relay terminal device.

21. The communication method according to any one of claims 15 to 20, characterized in that: The remote terminal device is in RRC connected state, RRC idle state or RRC inactive state.

22. A communication device, characterized in that: Comprising a unit for executing the communication method as claimed in any one of claims 1 to 14 or 15 to 21.

23. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed, the communication method according to any one of claims 1 to 14 or 15 to 21 is implemented.

24. A chip, characterized in that: It includes a processor, the processor is connected to a memory, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the chip executes the communication method as described in any one of claims 1 to 14 or 15 to 21.

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