A state conversion method and communication device

Abstract

The embodiment of the present application discloses a state transition method and communication device, the method comprising: a terminal receiving a radio resource control (RRC) release message sent by a base station, instructing the terminal to transition from an RRC connected state to an RRC inactive state; when the terminal needs to transition from an RRC inactive state to an RRC connected state, sending an RRC recovery request message to the base station; the terminal receiving an RRC recovery message sent by the base station and receiving uplink authorization resources allocated by the base station to the terminal; the terminal sending an uplink message to the base station based on the uplink authorization resources, the uplink message including a radio link control confirmation message and excluding data packets cached by the terminal in the RRC connected state; and the terminal sending an RRC recovery completion message to the base station. By adopting the embodiment of the present application, the problem of RLC asynchrony between the terminal and the base station can be avoided, thereby improving data transmission efficiency and user experience.

Description

Technical Field

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

[0002] Random access is a basic and important process in the New Radio (NR) system. In current and possible future random access scenarios, the states of the terminal include the following: Radio Resource Control (RRC) Idle State (RRC_IDLE), also known as the idle state, refers to the state of the terminal device when the terminal device is residing in the cell but not performing the random access process. The terminal device usually enters the idle state after being powered on or released. The RRC connected state (RRC_CONNECTED), also known as the connected state, refers to the state of the terminal device after completing the random access process and not performing RRC release. The terminal device can transmit data with the network device in the connected state. When the terminal device is in the idle state, after the terminal device completes the random access process, the state of the terminal device changes to the connected state. The RRC inactive state (RRC_INACTIVE), also known as the inactive state, is a state between the connected and idle states. For a terminal device in the inactive state, the user plane bearer of the air interface is suspended, while the user plane bearer and control plane bearer between the radio access network (RAN) and the core network (CN) are still maintained. When the terminal device initiates a call or service request, the user plane bearer of the air interface needs to be activated, and the existing user plane bearer and control plane bearer between the RAN and CN need to be reused.

[0003] The terminal can transition between the three states mentioned above. When the terminal transitions from the connected state to the inactive state, there may be some cached data packets in the radio link control (RLC) layer of the terminal. In the process of the terminal transitioning from the inactive state to the connected state, the RLC layer of the terminal will rebuild and clear these cached data packets. Because during the state transition process, there is a certain processing delay from the time the terminal receives the RRC recovery message sent by the base station to the time it parses the indication information for rebuilding the RLC and instructs the RLC layer to rebuild. During this processing delay, the terminal will send these cached data packets to the base station, so that the RLC layer of the base station is not empty. This results in the terminal being out of synchronization with the base station's RLC after the reconstruction of the terminal's RLC layer is completed, resulting in a radio link failure (RLF). Summary of the Invention

[0004] The technical problem to be solved by the embodiments of the present application is to provide a state transition method and a communication device to solve the problem of RLC asynchrony between the terminal and the base station during the state transition of random access, resulting in RLF.

[0005] In a first aspect, an embodiment of the present application provides a state transition method, which may include:

[0006] A terminal in a connected state receives a radio resource control (RRC) release message sent by a base station and switches from an RRC connected state to an RRC inactive state; when the terminal needs to switch from the RRC inactive state to an RRC connected state, the terminal sends an RRC recovery request message to the base station; then the terminal receives an RRC recovery message sent by the base station and receives uplink authorization resources allocated by the base station to the terminal; the terminal sends an uplink message to the base station based on the uplink authorization resources, the uplink message including a radio link control confirmation message and excluding data packets cached by the terminal in the RRC connected state; the terminal sends an RRC recovery completion message to the base station.

[0007] Since the terminal does not send the data packets cached in the RRC connection state during the RRC connection recovery process, the problem of RLC asynchrony between the terminal and the base station is avoided, ensuring the normal and timely transmission of data after the terminal is converted from the inactive state to the connected state, improving the efficiency of data transmission, and enhancing the user experience.

[0008] In a possible implementation, after the terminal receives the radio resource control (RRC) release message sent by the base station, the method further includes:

[0009] The terminal disables a function of sending data packets before sending an RRC recovery completion message to the base station.

[0010] By disabling the terminal's data packet sending function before the RRC recovery process, the purpose of not sending cached data packets during the RRC recovery process can be achieved, thereby ensuring RLC layer synchronization between the terminal and the base station and avoiding the RLF problem.

[0011] In a possible implementation, when the terminal configures the RRC recovery complete message or when the terminal sends the RRC recovery complete message to the base station, the method further includes:

[0012] The terminal resumes the function of sending data packets.

[0013] In a possible implementation, after the terminal receives the radio resource control (RRC) release message sent by the base station, the method further includes:

[0014] The terminal discards the buffered data packet before sending the RRC recovery request message to the base station.

[0015] By discarding the buffered data packets before the RRC recovery process, the purpose of not having buffered data packets during the RRC recovery process can be achieved, thereby ensuring RLC layer synchronization between the terminal and the base station and avoiding the RLF problem.

[0016] In a possible implementation, discarding the cached data packet includes:

[0017] The terminal starts a timer;

[0018] If the timer times out, the cached data packet is discarded.

[0019] In a possible implementation, after the terminal receives the radio resource control (RRC) release message sent by the base station, the method further includes:

[0020] Before receiving the RRC recovery message sent by the base station, the terminal re-establishes the radio link control RLC entity of the data radio bearer.

[0021] By reestablishing the RLC entity of the data radio bearer before the RRC recovery process, the purpose of no buffered data packets during the RRC recovery process can be achieved, thereby ensuring RLC layer synchronization between the terminal and the base station and avoiding the RLF problem.

[0022] In a second aspect, an embodiment of the present application provides a communication device, which may include:

[0023] a transceiver unit, configured to receive a radio resource control (RRC) release message sent by a base station, the RRC release message being used to instruct the terminal to transition from an RRC connected state to an RRC inactive state; when the communication device needs to transition from the RRC inactive state to an RRC connected state, the transceiver unit is further configured to send an RRC resume request message to the base station; receive the RRC resume message sent by the base station, and receive uplink authorization resources allocated by the base station to the terminal;

[0024] a processing unit, configured to instruct the transceiver unit to send an uplink message to the base station based on the uplink granted resources, where the uplink message includes a radio link control confirmation message and does not include a data packet buffered by the communication device in the RRC connected state;

[0025] The transceiver unit is further configured to send an RRC recovery completion message to the base station.

[0026] In a possible implementation manner, after the transceiver unit receives the radio resource control RRC release message sent by the base station, the processing unit is further configured to:

[0027] Before the transceiver unit sends the RRC recovery completion message to the base station, a function of sending data packets is disabled.

[0028] In a possible implementation, the processing unit is further configured to configure the RRC recovery complete message. When the processing unit configures the RRC recovery complete message or when the transceiver unit sends the RRC recovery complete message to the base station, the processing unit is further configured to:

[0029] Restore the ability to send data packets.

[0030] In a possible implementation manner, after the transceiver unit receives the radio resource control RRC release message sent by the base station, the processing unit is further configured to:

[0031] Before the transceiver unit sends the RRC recovery request message to the base station, the buffered data packet is discarded.

[0032] In a possible implementation, the processing unit is specifically configured to:

[0033] Start the timer;

[0034] If the timer times out, the cached data packet is discarded.

[0035] In a possible implementation manner, after the transceiver unit receives the radio resource control RRC release message sent by the base station, the processing unit is further configured to:

[0036] Before the transceiver unit receives the RRC recovery message sent by the base station, a radio link control RLC entity of the data radio bearer is rebuilt.

[0037] In a possible implementation, the communication device is a terminal.

[0038] In a third aspect, a device is provided. The device provided in this application has the function of implementing the terminal behavior in the above-mentioned method aspects, and includes means for performing the steps or functions corresponding to the steps or functions described in the above-mentioned method aspects. The steps or functions can be implemented by software, hardware (such as circuits), or a combination of hardware and software.

[0039] In one possible design, the apparatus includes one or more processors and a communication unit. The one or more processors are configured to support the apparatus in executing the corresponding functions of the terminal in the above method. For example, the control terminal sends an uplink message based on the uplink authorization resources allocated by the base station, and the uplink message does not include the data packets cached by the terminal when it is in the RRC connected state. The communication unit is used to support the apparatus in communicating with other devices to implement receiving and / or sending functions. For example, the apparatus enters the inactive state by receiving an RRC release message sent by the base station, and sends an RRC recovery request message to the base station to request to enter the connected state, etc.

[0040] Optionally, the device may further include one or more memories coupled to the processor to store program instructions and / or data necessary for the device. The one or more memories may be integrated with the processor or may be separate from the processor. This application is not limited thereto.

[0041] The device may be a smart terminal or a wearable device, etc., and the communication unit may be a transceiver or a transceiver circuit. Optionally, the transceiver may also be an input / output circuit or an interface.

[0042] The device may also be a communication chip. The communication unit may be an input / output circuit or an interface of the communication chip.

[0043] In another possible design, the above-mentioned device includes a transceiver, a processor, and a memory. The processor is used to control the transceiver or input / output circuit to transmit and receive signals, the memory is used to store a computer program, and the processor is used to execute the computer program in the memory, so that the device performs the method performed by the terminal in the first aspect or any possible implementation of the first aspect.

[0044] In a fourth aspect, a system is provided, which includes the above-mentioned base station and terminal.

[0045] In a fifth aspect, a computer-readable storage medium is provided for storing a computer program, wherein the computer program includes instructions for executing the method in the first aspect or any possible implementation of the first aspect.

[0046] In a sixth aspect, a computer program product is provided, comprising: a computer program code, which, when executed on a computer, enables the computer to execute the method in the first aspect or any possible implementation of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background technology, the drawings required for use in the embodiments of the present application or the background technology will be described below.

[0048] Figure 1 A schematic diagram of the architecture of a communication system provided in an embodiment of the present application;

[0049] Figure 2 Schematic diagram of the control plane protocol stack in the NR system;

[0050] Figure 3a A schematic diagram of the RLC layers of a terminal and a base station when a terminal transitions from a connected state to an inactive state in an existing state transition method;

[0051] Figure 3b A schematic diagram of the RLC layers of a terminal and a base station before and after RLC reestablishment is completed in a process where a terminal transitions from an inactive state to a connected state in an existing state transition method;

[0052] Figure 3c A schematic diagram of the RLC layers of a terminal and a base station when a terminal sends new data after transitioning from an inactive state to a connected state in an existing state transition method;

[0053] Figure 3d Schematic diagram of information interaction between a terminal and a base station after RLC of the terminal and the base station are out of synchronization;

[0054] Figure 4 A flow chart of a state transition method provided in an embodiment of the present application;

[0055] Figure 5 A flowchart of another state transition method provided in an embodiment of the present application;

[0056] Figure 6 A flowchart of another state transition method provided in an embodiment of the present application;

[0057] Figure 7 A flowchart of another state transition method provided in an embodiment of the present application;

[0058] Figure 8a A schematic diagram of the RLC layers of a terminal and a base station before and after RLC reestablishment is completed in a process in which a terminal transitions from an inactive state to a connected state in a state transition method provided in an embodiment of the present application;

[0059] Figure 8b Another schematic diagram of the RLC layers of a terminal and a base station before and after RLC reestablishment is completed in the process of the terminal converting from an inactive state to a connected state in the state conversion method provided in an embodiment of the present application;

[0060] Figure 8c A schematic diagram of the RLC layers of a terminal and a base station when a terminal sends new data after transitioning from an inactive state to a connected state in a state transition method provided in an embodiment of the present application;

[0061] Figure 9 A flow chart of a method for testing state transition provided in an embodiment of the present application;

[0062] Figure 10 A flowchart of another method for testing state transition provided in an embodiment of the present application;

[0063] Figure 11 A schematic diagram of the composition of a terminal provided in an embodiment of the present application;

[0064] Figure 12 A schematic diagram of the composition of another terminal provided in an embodiment of the present application. DETAILED DESCRIPTION

[0065] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0066] The terms "including" and "having" and any variations thereof in the specification and claims of this application and the accompanying drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements, but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0067] Please refer to Figure 1 , is a schematic diagram of the architecture of a communication system provided in an embodiment of the present application, which may include a base station 10 and at least one terminal 20.

[0068] Among them, the base station 10 can be an NR base station (gNB), an evolved Node B (eNB for short), a Node B (NB for short), a base station controller (BSC for short), a base transceiver station (BTS for short), a home base station (for example, Home evolved NodeB, or Home Node B, HNB for short), a baseband unit (BBU for short), etc. It can also be referred to as a base station transceiver, a wireless base station, a wireless transceiver, a transceiver function, a base station subsystem (BSS for short) or some other appropriate terms by those skilled in the art. It is an entity on the network side for transmitting or receiving signals. In an embodiment of the present application, the base station 10 can send an RRC release message to the terminal, carrying temporary configuration (suspendconfig) information, instructing the terminal 20 to switch from a connected state to an inactive state. When the terminal 20 wants to switch from the inactive state to the connected state, it can also receive an RRC resume request (RRC Resume Request) message sent by the terminal, then send an RRC resume (RRC Resume) message to the terminal, and allocate pre-scheduled uplink authorization resources to the terminal 20.

[0069] The terminal 20 may also be referred to as user equipment (UE). It may be deployed on land, including indoors or outdoors, handheld, wearable, or vehicle-mounted; it may also be deployed on water (such as on ships); or it may be deployed in the air (for example, on airplanes, balloons, and satellites). It may also be referred to as a user terminal, terminal equipment, access terminal equipment, vehicle-mounted terminal, industrial control terminal, UE unit, UE station, mobile station, mobile station, remote station, remote terminal equipment, mobile device, UE terminal equipment, mobile terminal, wireless communication equipment, UE agent, or UE device. The terminal may also be fixed or mobile. Its specific form can be a mobile phone, a tablet computer, a computer with wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a vehicle-mounted terminal device, a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, a wearable terminal device, etc. It is an entity on the user side for receiving or transmitting signals. In the embodiment of the present application, the terminal 20 can receive the RRC release message sent by the base station 10 and convert the connected state to the inactive state. After receiving the RRC release message, the terminal 20 can pre-process any cached data packets that may exist, such as temporarily shutting down the terminal 20's function of sending data packets, discarding cached data packets, or re-establishing the RLC entity of the data radio bearer (DRB) in advance, so as to achieve the purpose of not sending data packets to the base station during the subsequent transition from the inactive state to the connected state, thereby ensuring RLC synchronization between the terminal 20 and the base station 10. When the terminal 20 needs to transition from the inactive state to the connected state, it can send an RRC recovery request message to the base station 10, then receive the RRC recovery message sent by the base station 10, feedback a radio link control (Radio Link Control, RLC) confirmation message (RLCACK message) based on the uplink authorized resources allocated by the base station 10, and then send an RRC resume complete message to transition from the inactive state to the connected state. For the sake of simplicity of description, the embodiment of the present application only shows one terminal 20. In actual scenarios, the number of terminals 20 can be one or more. Some terminals can also serve as transfer devices to transfer messages for other terminals, and user groups can be formed between terminals, etc. The embodiment of the present application does not impose any restrictions.

[0070] For ease of explanation, the embodiments of the present invention are described using a New Radio (NR) system. The implementation methods in the embodiments of the present invention are also applicable to other existing communication systems and future higher-level communication systems such as 6G and 7G, and the embodiments of the present invention are not limited in any way.

[0071] See Figure 2 , which is a schematic diagram of the control plane protocol stack in the NR system. Among them, the control plane protocol stack on the terminal side includes: physical (PHY) layer, medium access control (MAC) layer, RLC layer, packet data convergence protocol (PDCP) layer, RRC layer and non-access stratum (NAS) layer, and the control protocol layer on the base station side includes: PHY layer, MAC layer, RLC layer, PDCP layer and RRC layer. All the protocol stacks of the terminal are located in the terminal; on the network side, the NAS layer is not located on the base station, but on the authentication management function (AMF) entity of the core network.

[0072] The RRC layer is primarily responsible for handling all signaling between terminals and the NG-RAN (5G access network) (messages between users and base stations). Its main functions include broadcasting system messages, paging, establishing / maintaining / releasing RRC connections, establishing / configuring / maintaining / releasing SRBs and DRBs, and mobility. The PDCP layer's main functions include header compression, encryption / decryption, sequencing, and duplicate detection. The RLC layer's main functions include packet segmentation / reassembly, and error correction.

[0073] In the existing state transition method, there is a 60ms delay when the terminal transitions from the connected state to the active state. The terminal may have uplink data to send within this 60ms, which will cause some buffered data packets in the RLC layer of the terminal. When the terminal enters the inactive state, these buffered data packets will still exist. Please refer to the existing standard process for processing. Figure 3a 、 Figure 3b 、 Figure 3c and Figure 3d , Figure 3a A schematic diagram of the RLC layers of a terminal and a base station when a terminal transitions from a connected state to an inactive state in an existing state transition method; Figure 3b A schematic diagram of the RLC layers of a terminal and a base station before and after RLC reestablishment is completed in a process where a terminal transitions from an inactive state to a connected state in an existing state transition method; Figure 3cA schematic diagram of the RLC layers of a terminal and a base station when a terminal sends new data after transitioning from an inactive state to a connected state in an existing state transition method; Figure 3d Schematic diagram of information interaction between the terminal and the base station after the RLC of the terminal and the base station are out of synchronization; Figure 3a As shown in FIG, for example, the RLC layer of the terminal has three buffered data packets numbered 4, 5, and 6. The RLC layer of the base station is empty when it does not receive the buffered data packets of the terminal. Figure 3b As shown, before the RLC reconstruction is completed in the process of the terminal converting from the inactive state to the connected state, the RRC layer of the terminal has not yet parsed the field of reestablishing RLC contained in the RRC recovery message, or the RRC layer has parsed the field, but the RLC layer has not received the RRC's instruction to reestablish RLC. At this time, the RLC layer receives the transmission opportunity indicated by the MAC layer, and the terminal will send the three data packets cached in the RLC layer to the base station. After the base station receives the data packets sent by the terminal, the RLC layer of the base station also has three data packets numbered 4, 5, and 6. When the terminal performs RLC reconstruction, the terminal will clear the RLC cache, such as discarding all RLC service data units (SDU), RLC SDU segments and RLC protocol data units (PDU), etc.; and complete operations such as stopping and resetting all timers, resetting all state variables to initial values, etc. After the terminal completes the RLC reconstruction, the RLC layer of the terminal is empty, and the RLC layer of the base station still has three data packets numbered 4, 5, and 6. As shown Figure 3c As shown in the figure, when the terminal changes from the inactive state to the connected state and sends new data, for example, to send a new data packet, the terminal will number the new data packet to get the number 0. Then send it to the base station. At this time, the RLC on the terminal side and the base station side are not synchronized. Figure 3dAs shown, in step S301, the terminal sends a new data packet numbered 0 to the base station. Since the base station's RLC layer already holds three data packets previously sent by the terminal, namely, data packets 4, 5, and 6, upon receiving the new data packet numbered 0 from the terminal, the base station sends an RLC status report to the terminal in step S302, indicating that the next data packet to be received is numbered 7. Upon receiving the RLC status report from the base station, the terminal deems it to be erroneous and discards it in step S303. In step S304, the terminal retransmits data packet numbered 0. In step S305, the terminal receives another RLC status report from the base station, indicating that the next data packet to be received is numbered 7. In step S306, the terminal discards the RLC status report again, and steps S304-S306 are repeated between the terminal and the base station until the preset maximum number of retransmissions is reached. If the retransmissions still fail after reaching the preset maximum number, an RLF occurs. In this case, in step S307, the terminal can send an RRC reestablishment request to the base station to reestablish a new RRC connection. During the entire process, the resources and power consumption of the terminal and base station are wasted, and the data processing becomes inefficient, which in turn leads to a poor user experience for the end user.

[0074] Therefore, this application provides a method for state conversion. Figures 4-10 The state conversion method provided in this application is described in detail.

[0075] See Figure 4 , which is a flow chart of a state transition method provided in an embodiment of the present application; applied to a terminal in a connected state, specifically comprising the following steps:

[0076] S401: The base station sends an RRC release message to the terminal.

[0077] The RRC release message carries suspend configuration information, and the RRC release message is used to instruct the terminal to switch from the RRC connected state to the RRC inactive state.

[0078] S402: After receiving the RRC release message, the terminal switches from the RRC connected state to the RRC inactive state.

[0079] Since the terminal may have buffered data packets that have not been sent when it is in the RRC connected state, when the terminal is converted from the RRC connected state to the RRC inactive state, its RLC layer still has buffered data packets.

[0080] When the terminal needs to switch from the RRC inactive state to the RRC connected state, the following steps may be performed:

[0081] S403: The terminal sends an RRC recovery request message to the base station.

[0082] S404: The base station responds to the RRC recovery request message of the terminal and sends an RRC recovery message to the terminal.

[0083] The RRC recovery message includes a Reestablish RLC field. The RRC layer of the terminal parses the RRC recovery message and, after reading the field, can instruct the RLC layer to perform RLC reestablishment.

[0084] S405: The base station allocates uplink grant (UL grant) resources to the terminal.

[0085] S406: The terminal sends an uplink message to the base station based on the uplink authorized resources.

[0086] The uplink message includes a radio link control confirmation message and does not include a data packet buffered by the terminal in the RRC connected state.

[0087] S407: The terminal sends an RRC recovery complete message to the base station, completing the transition from the RRC inactive state to the RRC connected state.

[0088] When the terminal re-enters the connected state, if there are data packets that need to be sent, the terminal can number these data packets and send them to the terminal in sequence.

[0089] In the embodiment of the present application, since the terminal does not send the data packets cached in the RRC connection state during the RRC connection recovery process, the problem of RLC asynchrony between the terminal and the base station is avoided, and the normal and timely transmission of data after the terminal is converted from the inactive state to the connected state is ensured, thereby improving the efficiency of data transmission and enhancing the user experience.

[0090] In order to achieve the purpose of not sending the data packets cached in the RRC connection state during the RRC connection recovery process, the terminal can use Figure 5-Figure 7 The method described.

[0091] See Figure 5 , which is a flow chart of another state transition method provided in an embodiment of the present application; comprising:

[0092] S501: The base station sends an RRC release message to the terminal, carrying suspension configuration information.

[0093] S502: The terminal turns off the function of sending data packets.

[0094] Optionally, after receiving the RRC release message, the PHY layer of the terminal transmits it upward to the RRC layer. The RRC layer can then instruct the RLC layer to disable the function of sending data packets. The RLC layer will not send data packets until it receives an instruction from a higher layer to resume the function of sending data packets.

[0095] In another implementation, after receiving the RRC release message, the terminal's PHY layer transmits it upward to the RRC layer. The PDCP layer may then receive a PDCP suspend indication from the RRC layer, which in turn instructs the RLC layer to disable data packet transmission. The RLC layer will not transmit data packets until it receives an indication from a higher layer to resume data packet transmission.

[0096] S503: The terminal switches from the connected state to the inactive state according to the instruction of the RRC release message.

[0097] It should be noted that there is no strict order between step S502 and step S503. The terminal's function of shutting down the sending of data packets can be triggered by an RRC release message. When the terminal receives the RRC release message, the operation of shutting down the sending of data packets is immediately executed. The operation can also be performed after step S503, or it can be performed simultaneously with step S503. This embodiment of the present application does not impose any limitations.

[0098] The terminal's function of disabling data packet sending may include:

[0099] If the terminal is sending data packets in the connected state, it stops sending data packets after receiving the RRC release message;

[0100] If the terminal does not send a data packet in the connected state, after receiving the RRC release message, the terminal's function of sending data packets is disabled or prohibited.

[0101] S504: The terminal sends an RRC recovery request message to the base station.

[0102] S505: The base station sends an RRC recovery message to the terminal.

[0103] S506: The base station allocates uplink authorization resources to the terminal.

[0104] S507: The terminal sends an RLC ACK message to the base station.

[0105] S508: The terminal resumes the function of sending data packets.

[0106] Optionally, the RRC layer or the PDCP layer may instruct the RLC layer to resume the function of sending data packets.

[0107] S509: The terminal sends an RRC recovery completion message to the base station.

[0108] Optionally, step S508 may be performed when the terminal configures the RRC recovery completion message to be sent, or may be performed simultaneously with step S509. After the terminal recovers the function of sending data packets, the terminal may send data packets to the base station.

[0109] For details on the changes in the RLC layer on the terminal side and the base station side when implementing the method of this embodiment, please refer to Figure 8a and Figure 8c , Figure 8a A schematic diagram of the RLC layers of a terminal and a base station before and after RLC reestablishment is completed in a process in which a terminal transitions from an inactive state to a connected state in a state transition method provided in an embodiment of the present application; Figure 8c Schematic diagram of the RLC layer of the terminal and the base station when the terminal sends new data after converting from the inactive state to the connected state in the state conversion method provided in the embodiment of the present application. Figure 8a As shown in the figure, since the terminal has disabled the function of sending data packets before RLC is reestablished, there are three buffered data packets, 4, 5, and 6, in the RLC layer of the terminal, and the RLC layer of the base station is empty. After the terminal reestablishes RLC, the RLC layer of the terminal is empty, and the RLC layer of the base station is also empty. Figure 8c As shown in the figure, when the terminal is converted from an inactive state to a connected state and needs to send new data, if the new data includes 4 cached data packets 0, 1, 2, and 3, the terminal can send these 4 data packets to the base station in sequence. After the RLC layer of the base station receives the data packets sent by the terminal, its RLC layer also includes 4 cached data packets 0, 1, 2, and 3, thereby achieving the RLC synchronization effect between the terminal and the base station.

[0110] In an embodiment of the present application, by turning off the function of the terminal to send data packets before the RRC recovery process, the purpose of not sending cached data packets during the RRC recovery process can be achieved, thereby ensuring the synchronization of the RLC layers of the terminal and the base station and avoiding the RLF problem.

[0111] See Figure 6 , another state transition method provided in an embodiment of the present application, comprising:

[0112] S601: The base station sends an RRC release message to the terminal, carrying suspension configuration information.

[0113] S602: The terminal discards the cached data packet.

[0114] Optionally, after receiving the RRC release message, the PHY layer of the terminal transmits it upward to the RRC layer, and then the RRC layer can instruct the RLC layer to discard the buffered data packets.

[0115] In another implementation, after receiving the RRC release message, the terminal's PHY layer transmits it upward to the RRC layer. The PDCP layer may then receive a PDCP suspend indication from the RRC layer, and then instruct the RLC layer to discard the buffered data packets.

[0116] Furthermore, the terminal may discard the data packet immediately after receiving the RRC release message, or may start a timer and, if the timer times out, discard the data packet.

[0117] S603: The terminal switches from the connected state to the inactive state.

[0118] It should be noted that there is no strict order between step S602 and step S603. The operation of the terminal discarding the cached data packet can be triggered by the RRC release message. When the terminal receives the RRC release message, the operation of discarding the cached data packet is performed immediately. The operation can also be performed after step S603, or it can be performed simultaneously with step S603. The embodiment of the present application does not impose any limitations.

[0119] S604: The terminal sends an RRC recovery request message to the base station.

[0120] S605: The base station sends an RRC recovery message to the terminal.

[0121] S606: The base station allocates uplink authorization resources to the terminal.

[0122] S607: The terminal sends a radio link confirmation message to the base station.

[0123] S608: The terminal sends an RRC recovery completion message to the base station.

[0124] For details on the changes in the RLC layer on the terminal side and the base station side when implementing the method of this embodiment, please refer to Figure 8b and Figure 8c , is another schematic diagram of the RLC layers of the terminal and the base station before and after RLC reestablishment is completed in the process of the terminal converting from the inactive state to the connected state in the state conversion method provided in an embodiment of the present application; Figure 8c Schematic diagram of the RLC layer of the terminal and the base station when the terminal sends new data after converting from the inactive state to the connected state in the state conversion method provided in the embodiment of the present application. Figure 8b As shown in , since the terminal discarded the cached data packets before RLC was reestablished, the RLC layer of the terminal is empty and the RLC layer of the base station is empty. After the terminal reestablishes RLC, the RLC layer of the terminal is empty and the RLC layer of the base station is also empty. Figure 8cAs shown in the figure, when the terminal is converted from an inactive state to a connected state and needs to send new data, if the new data includes 4 cached data packets 0, 1, 2, and 3, the terminal can send these 4 data packets to the base station in sequence. After the RLC layer of the base station receives the data packets sent by the terminal, its RLC layer also includes 4 cached data packets 0, 1, 2, and 3, thereby achieving the RLC synchronization effect between the terminal and the base station.

[0125] In an embodiment of the present application, by discarding the cached data packets before the RRC recovery process, the purpose of no cached data packets during the RRC recovery process can be achieved, thereby ensuring the RLC layer synchronization of the terminal and the base station and avoiding the RLF problem.

[0126] Please refer to Figure 7 , is a flow chart of another state transition method provided in an embodiment of the present application; step S701 and Figure 6 The same as step S601, steps S703-S708 are the same as S603-S608, and after step S701, the following is further included:

[0127] S702: The terminal re-establishes the RLC entity of the data radio bearer.

[0128] The difference between step S702 and step S602 is that reestablishing the RLC entity includes discarding buffered data packets and also includes some operations such as stopping and resetting all timers and resetting all state variables to initial values.

[0129] Optionally, after receiving the RRC release message, the PHY layer of the terminal transmits it upward to the RRC layer. The PDCP layer may then receive a PDCP suspend indication from the RRC layer, and then the PDCP layer instructs the RLC layer to reestablish the RLC entity of the data radio bearer.

[0130] It should be noted that there is no strict order between step S702 and step S703. The operation of the terminal to reconstruct the RLC entity of the data radio bearer can be triggered by the RRC release message. The operation can be performed immediately after the terminal receives the RRC release message, or it can be performed after step S703, or it can be performed simultaneously with step S703. The embodiment of this application does not impose any limitations.

[0131] For details on the changes in the RLC layer on the terminal side and the base station side when implementing the method of this embodiment, please refer to Figure 8b and Figure 8c , I will not go into details here.

[0132] In an embodiment of the present application, by rebuilding the RLC entity of the data radio bearer before the RRC recovery process, the purpose of no cached data packets during the RRC recovery process can be achieved, thereby ensuring the synchronization of the RLC layers of the terminal and the base station and avoiding the problem of RLF.

[0133] To verify Figure 5-Figure 7 The reliability of the method can be tested by Figure 9-10 The test was performed as described.

[0134] See Figure 9 , which is a flow chart of a method for testing state transition provided in an embodiment of the present application; can be applied to Figure 5 The state transition method shown includes:

[0135] S901: The terminal reports a first buffer status report (BSR) to inform the base station that there are buffered data packets in the terminal.

[0136] S902: The base station sends an RRC release message to the terminal, carrying suspension configuration information.

[0137] S903: The terminal turns off the function of sending data packets.

[0138] S904: The terminal switches from the connected state to the inactive state.

[0139] S905: The terminal sends an RRC recovery request message to the base station and reports a second buffer status report to inform the base station that there is a buffered data packet in the terminal. At this time, the second BSR is not 0.

[0140] S906: The base station sends an RRC recovery message to the terminal.

[0141] S907: The base station allocates uplink authorization resources to the terminal.

[0142] S908: The terminal sends an RLC ACK message to the base station.

[0143] S909: The terminal resumes the function of sending data packets.

[0144] S910: The terminal sends an RRC recovery complete message to the base station.

[0145] In the process of steps S905-S909, the first BSR and the second BSR prove that the terminal does have a cached data packet before these steps. If the terminal detects that the terminal has not sent a data packet or the base station detects that the base station has not received a data packet, it is proved that the data packet has been received. Figure 5 The manner of the embodiment shown achieves the purpose of ensuring RLC synchronization between the terminal and the base station.

[0146] See Figure 10 , which is a flow chart of another method for testing state transition provided by an embodiment of the present application; it can be used to test Figure 6-Figure 7 The state transition method of the illustrated embodiment includes the following steps:

[0147] S1001: The terminal reports a first buffer status report (BSR) to inform the base station that there are buffered data packets in the terminal.

[0148] S1002: The base station sends an RRC release message to the terminal, carrying suspension configuration information.

[0149] S1003: The terminal discards the buffered data packet or re-establishes the RLC entity of the data radio bearer.

[0150] S1004: The terminal switches from the connected state to the inactive state.

[0151] S1005: The terminal sends an RRC recovery request message to the base station and reports a second buffer status report, informing the base station that there is no buffered data packet in the terminal. At this time, the second BSR is 0.

[0152] S1006: The base station sends an RRC recovery message to the terminal.

[0153] S1007: The base station allocates uplink authorization resources to the terminal.

[0154] S1008: The terminal sends an RLC ACK message to the base station.

[0155] S1009: The terminal sends an RRC recovery completion message to the base station.

[0156] The first BSR proves that there are cached data packets when the terminal is converted from connected state to inactive state, and the second BSR proves that there are no cached data packets before the terminal is converted from inactive state to connected state, which means that the cached data packets have been cleared before RRC recovery. In the process of steps S1005-S1008, if the terminal side detects that the terminal has not sent a data packet or the base station side detects that the base station has not received a data packet, it proves that the data packet has been cleared before RRC recovery. Figure 6 or Figure 7 The manner of the embodiment shown achieves the purpose of ensuring RLC synchronization between the terminal and the base station.

[0157] See Figure 11 , is a schematic diagram of the composition of a communication device provided in an embodiment of the present application; comprising:

[0158] The transceiver unit 100 is configured to receive a radio resource control (RRC) release message sent by a base station, the RRC release message being used to instruct the terminal to transition from an RRC connected state to an RRC inactive state; when the communication device needs to transition from the RRC inactive state to an RRC connected state, the transceiver unit is further configured to send an RRC resume request message to the base station; receive the RRC resume message sent by the base station, and receive uplink authorization resources allocated by the base station to the terminal;

[0159] The processing unit 200 is configured to instruct the transceiver unit to send an uplink message to the base station based on the uplink granted resource, where the uplink message includes a radio link control confirmation message and does not include a data packet buffered by the communication device in the RRC connected state;

[0160] The transceiver unit 100 is further configured to send an RRC recovery completion message to the base station.

[0161] In a possible implementation, after the transceiver unit 100 receives the radio resource control RRC release message sent by the base station, the processing unit 200 is further configured to:

[0162] Before the transceiver unit sends the RRC recovery completion message to the base station, a function of sending data packets is disabled.

[0163] In a possible implementation, the processing unit 200 is further configured to configure the RRC recovery complete message. When the processing unit 200 configures the RRC recovery complete message or when the transceiver unit 100 sends the RRC recovery complete message to the base station, the processing unit 200 is further configured to:

[0164] Restore the ability to send data packets.

[0165] In a possible implementation, after the transceiver unit 100 receives the radio resource control RRC release message sent by the base station, the processing unit 200 is further configured to:

[0166] Before the transceiver unit 100 sends the RRC recovery request message to the base station, the buffered data packet is discarded.

[0167] In a possible implementation, the processing unit 200 is specifically configured to:

[0168] Start the timer;

[0169] If the timer times out, the cached data packet is discarded.

[0170] In a possible implementation, after the transceiver unit 100 receives the radio resource control RRC release message sent by the base station, the processing unit 200 is further configured to:

[0171] Before the transceiver unit 100 receives the RRC recovery message sent by the base station, the radio link control RLC entity of the data radio bearer is rebuilt.

[0172] In a possible implementation, the communication device is a terminal.

[0173] See Figure 12 , is a schematic diagram of the composition of another communication device provided in an embodiment of the present application; Figure 12 As shown, the communication device may include a processor 110, a memory 120, and a transceiver 130. The processor 110, the memory 120, and the transceiver 130 are connected via a bus 140. The memory 120 is used to store instructions, and the processor 110 is used to execute the instructions stored in the memory 120 to implement the above Figure 4-Figure 7 、 Figure 9-10 The steps executed by the terminal in the corresponding method.

[0174] The processor 110 is used to execute the instructions stored in the memory 120 to control the transceiver 130 to receive and send signals and complete the steps performed by the terminal in the above method. The memory 120 can be integrated into the processor 110 or set separately from the processor 110.

[0175] As an implementation, the functions of the transceiver 130 may be implemented by a transceiver circuit or a dedicated transceiver chip. The processor 110 may be implemented by a dedicated processing chip, a processing circuit, a processor, or a general-purpose chip.

[0176] As another implementation, a general-purpose computer can be used to implement the terminal provided in the embodiments of the present application. The program code for implementing the functions of the processor 110 and the transceiver 130 is stored in the memory 120, and the general-purpose processor implements the functions of the processor 110 and the transceiver 130 by executing the code in the memory 120.

[0177] For the concepts, explanations, detailed descriptions and other steps involved in the communication device and related to the technical solutions provided in the embodiments of the present application, please refer to the descriptions of these contents in the aforementioned methods or other embodiments, which will not be repeated here.

[0178] As another form of this embodiment, a computer-readable storage medium is provided, on which instructions are stored. When the instructions are executed, the terminal-side method in the above method embodiment is executed.

[0179] As another form of this embodiment, a computer program product including instructions is provided, which, when executed, performs the terminal-side method in the above method embodiment.

[0180] Those skilled in the art will understand that for ease of explanation, Figure 12 Only one memory and processor are shown. In an actual controller, multiple processors and memories may exist. The memory may also be referred to as a storage medium or storage device, etc., which is not limited in the embodiments of the present application.

[0181] It should be understood that in the embodiments of the present application, the processor may be a central processing unit (CPU), and the processor may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0182] It should also be understood that the memory mentioned in the embodiments of the present invention 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 random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct RAMbus RAM (DR RAM).

[0183] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, the memory (storage module) is integrated into the processor.

[0184] It should be noted that the memory described herein is intended to include, but not be limited to, these and any other suitable types of memory.

[0185] In addition to the data bus, the bus may also include a power bus, a control bus, a status signal bus, etc. However, for the sake of clarity, various buses are labeled as buses in the figure.

[0186] It should also be understood that the first, second, third, fourth and various numerical numbers involved in this document are only distinctions made for the convenience of description and are not intended to limit the scope of this application.

[0187] It should be understood that the term "and / or" in this document simply describes a relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0188] During implementation, each step of the above method 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 conjunction with its hardware. To avoid repetition, it will not be described in detail here.

[0189] According to the method provided in the embodiment of the present application, the embodiment of the present application also provides a system, which includes the aforementioned base station and terminal, etc.

[0190] In various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0191] Those skilled in the art will appreciate that the various illustrative logical blocks (ILBs) 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 implementations should not be considered beyond the scope of this application.

[0192] 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.

[0193] 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.

[0194] 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.

[0195] In the above embodiments, it 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. When the computer program instructions 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 device. 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 via a wired (e.g., coaxial cable, optical fiber, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) method. 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 can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state hard disk).

[0196] 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 state transition method, characterized in that: include: The terminal receives a radio resource control (RRC) release message sent by the base station, where the RRC release message is used to instruct the terminal to switch from an RRC connected state to an RRC inactive state; When the terminal needs to switch from the RRC inactive state to the RRC connected state, the terminal sends an RRC recovery request message to the base station; The terminal receives the RRC recovery message sent by the base station, and receives the uplink authorization resources allocated by the base station to the terminal; The terminal sends an uplink message to the base station based on the uplink granted resource, where the uplink message includes a radio link control confirmation message and does not include a data packet buffered by the terminal in the RRC connected state; The terminal sends an RRC recovery complete message to the base station.

2. The method according to claim 1, characterized in that After the terminal receives the radio resource control RRC release message sent by the base station, the method further includes: The terminal disables a function of sending data packets before sending an RRC recovery completion message to the base station.

3. The method according to claim 2, characterized in that When the terminal configures the RRC recovery complete message or when the terminal sends the RRC recovery complete message to the base station, the method further includes: The terminal resumes the function of sending data packets.

4. The method according to claim 1, wherein After the terminal receives the radio resource control RRC release message sent by the base station, the method further includes: The terminal discards the buffered data packet before sending the RRC recovery request message to the base station.

5. The method according to claim 4, characterized in that Said discarding said cached data packet comprises: The terminal starts a timer; If the timer times out, the cached data packet is discarded.

6. The method according to claim 1, wherein After the terminal receives the radio resource control RRC release message sent by the base station, the method further includes: Before receiving the RRC recovery message sent by the base station, the terminal re-establishes the radio link control RLC entity of the data radio bearer.

7. A communication device, characterized in that: include: a transceiver unit, configured to receive a radio resource control (RRC) release message sent by a base station, the RRC release message being used to instruct the communication device to transition from an RRC connected state to an RRC inactive state; when the communication device needs to transition from the RRC inactive state to an RRC connected state, the transceiver unit is further configured to send an RRC resume request message to the base station; receive the RRC resume message sent by the base station, and receive uplink authorization resources allocated by the base station to the communication device; a processing unit, configured to instruct the transceiver unit to send an uplink message to the base station based on the uplink granted resources, where the uplink message includes a radio link control confirmation message and does not include a data packet buffered by the communication device in the RRC connected state; The transceiver unit is further configured to send an RRC recovery completion message to the base station.

8. The communication device according to claim 7, wherein: After the transceiver unit receives the radio resource control RRC release message sent by the base station, the processing unit is further configured to: Before the transceiver unit sends the RRC recovery completion message to the base station, a function of sending data packets is disabled.

9. The communication device according to claim 8, wherein: The processing unit is further configured to configure the RRC recovery complete message. When the processing unit configures the RRC recovery complete message or when the transceiver unit sends the RRC recovery complete message to the base station, the processing unit is further configured to: Restore the ability to send data packets.

10. The communication device according to claim 7, wherein: After the transceiver unit receives the radio resource control RRC release message sent by the base station, the processing unit is further configured to: Before the transceiver unit sends the RRC recovery request message to the base station, the buffered data packet is discarded. The communication device according to claim 10 , wherein: The processing unit is specifically configured to: Start the timer; If the timer times out, the cached data packet is discarded.

12. The communication device according to claim 7, wherein: After the transceiver unit receives the radio resource control RRC release message sent by the base station, the processing unit is further configured to: Before the transceiver unit receives the RRC recovery message sent by the base station, a radio link control RLC entity of the data radio bearer is rebuilt.

13. The communication device according to any one of claims 7 to 12, characterized in that: The communication device is a terminal.

14. A communication device, characterized in that: include: A processor, a memory, and a bus, wherein the processor and the memory are connected via a bus, wherein the memory is used to store a set of program codes, and the processor is used to call the program codes stored in the memory to execute the method according to any one of claims 1 to 6.

15. A computer-readable storage medium, characterized in that include: The computer-readable storage medium stores instructions, which, when executed on a computer, implement the method according to any one of claims 1 to 6.

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