Method and system for synchronous configuration after RRC (Radio Resource Control) connection reestablishment

Abstract

The invention discloses a method for synchronous configuration after RRC (Radio Resource Control) connection reestablishment. And the UE sends an RRC connection reestablishment request message to the target base station. The target base station has the context of the UE, and the target base station sends an RRC connection reestablishment message to the UE. And the UE sends an RRC connection reestablishment completion message to the target base station. And the target base station judges whether an RRC reconfiguration message which has been sent but is not confirmed by the UE exists or not. And if so, the target base station releases the old UE configuration, regenerates a new UE configuration, and sends an RRC reconfiguration message containing the full configuration cell and the new UE configuration to the UE. And the UE processes the new RRC reconfiguration message, sends an RRC reconfiguration completion message corresponding to the new RRC reconfiguration message to the target base station, and recovers data transmission of the data radio bearer and the signaling radio bearer at the same time. The present application ensures that the configuration of the UE and the target base station is consistent after the RRC connection is reestablished, and the UE can work normally.

Description

Technical Field

[0001] The present application relates to a mobile communication technology, and in particular to a method for synchronous configuration after RRC (Radio Resource Control) connection reestablishment. Background Art

[0002] In 4G and 5G mobile communication systems, when a UE (user equipment) in an RRC connected state (RRC_CONNECTED) detects a problem with the RRC connection, such as a radio link failure, the RRC connection can be restored through RRC connection re-establishment (RRC connection re-establishment, or RRC re-establishment).

[0003] When reestablishing the RRC connection, the UE first selects a suitable cell through the cell selection process, and then initiates the RRC connection reestablishment signaling interaction on the cell. For the convenience of description, the serving cell before the UE reestablishes the RRC connection is referred to as the source cell, the base station that controls the source cell is referred to as the source base station, the serving cell where the UE initiates the RRC connection reestablishment is referred to as the target cell, and the base station that controls the target cell is referred to as the target base station. In 4G and 5G mobile communication systems, a base station can control one or more cells, so the source base station and the target base station may be the same base station.

[0004] See also Figure 1 , the existing RRC connection reestablishment process includes the following steps.

[0005] Step S11: The UE sends an RRC connection reestablishment request message to the target base station. In the 4G mobile communication system, this refers to the RRCConnectionReestablishmentRequest message, and in the 5G mobile communication system, this refers to the RRCReestablishmentRequest message. The RRC connection reestablishment request message contains the Cell Radio Network Temporary Identifier (C-RNTI) assigned to the UE by the source cell, the physical cell identity (PCI) of the source cell, etc.

[0006] Step S12: If the target base station does not have the UE context (UE Context) locally, the target base station sends a RETRIEVE UE CONTEXT REQUEST message to the source base station to request the UE context.

[0007] Step S13: The source base station sends a RETRIEVE UE CONTEXT RESPONSE message to the target base station to return the UE context, which includes UE capabilities, security context, radio bearer configuration, measurement configuration, and the like.

[0008] If the target base station has the UE context locally, step S12 and step S13 are omitted.

[0009] Step S14: The target base station sends an RRC connection reestablishment message to the UE. In a 4G mobile communication system, this refers to an RRCConnectionReestablishment message, and in a 5G mobile communication system, this refers to an RRCReestablishment message.

[0010] Step S15: The UE sends an RRC connection reestablishment complete message to the target base station. In a 4G mobile communication system, this refers to an RRCConnectionReestablishmentComplete message, and in a 5G mobile communication system, this refers to an RRCReestablishmentComplete message.

[0011] Step S16: The target base station sends an RRC reconfiguration message to the UE. In a 4G mobile communication system, this refers to an RRCConnectionReconfiguration message, and in a 5G mobile communication system, this refers to an RRCReconfiguration message. Step S16 may be performed before step S15.

[0012] Step S17: The UE sends an RRC reconfiguration complete message to the target base station and resumes data transmission of the data radio bearer (DRB), signaling radio bearer (SRB) SRB 2 and SRB 4. The RRC reconfiguration complete message refers to the RRCConnectionReconfigurationComplete message in the 4G mobile communication system and refers to the RRCReconfigurationComplete message in the 5G mobile communication system.

[0013] According to the existing communication protocol, the UE will release the UE configuration such as the physical layer configuration before issuing the RRC connection reestablishment request, and the UE will not inherit the UE configuration such as the physical layer configuration after the RRC connection is reestablished. The UE configuration such as the radio bearer configuration and the measurement configuration can be inherited after the RRC connection is reestablished, and the target base station can modify or continue to use the UE configuration such as the radio bearer configuration and the measurement configuration in the RRC reconfiguration message.

[0014] If the communication protocol version supported by the target base station is lower than that of the source base station, the target base station cannot parse the radio bearer configuration and measurement configuration in the retrieve UE context response message sent by the source base station in step S13, then the target base station will release the radio bearer configuration and measurement configuration, and carry the fullConfig (full configuration) information element in the RRC reconfiguration message. After receiving the RRC reconfiguration message carrying the full configuration information element, the UE first releases the radio bearer configuration and measurement configuration, and then executes the configuration in the RRC reconfiguration message, that is, it does not inherit the radio bearer configuration and measurement configuration before the RRC reconfiguration. This process is called full configuration.

[0015] In 4G and 5G mobile communication systems, the base station can establish or modify the configuration of the UE in the RRC connected state through the RRC reconfiguration message. The RRC reconfiguration message is transmitted on SRB 1, using the RLC (Radio Link Control) AM (Acknowledged Mode) mode. The RLC entity in AM mode ensures reliable data transmission through ARQ (Automatic Repeat Request). The RRC layer of the base station passes the RRC reconfiguration message to the PDCP (Packet Data Convergence Protocol) layer. The PDCP takes the RRC reconfiguration message as a PDCP SDU (Service Data Unit) and encapsulates it into a PDCP PDU (Protocol Data Unit) and passes it to the RLC layer of the base station. The RLC layer of the base station takes the PDCP PDU as an RLC SDU, and further encapsulates it into one or more RLC PDUs and passes it to the MAC (Medium Access Control) layer of the base station. The MAC layer of the base station uses the RLC PDU as the MAC SDU, and encapsulates the MAC SDU into the MAC PDU through multiplexing and maps it to the transport blocks (TB) for transmission. The MAC layer of the base station ensures the reliable transmission of data through HARQ (Hybrid ARQ, hybrid automatic repeat request). After receiving the transport block, the MAC layer of the UE sends a confirmation to the MAC layer of the base station through the HARQ entity, and passes the MAC SDU to the RLC layer of the UE. After receiving the complete RLC SDU, the RLC layer of the UE sends a confirmation to the RLC layer of the base station through the ARQ entity, and passes it to the PDCP layer of the UE. The PDCP layer of the UE passes it to the RRC layer of the UE. After processing, the RRC layer of the UE sends an RRC reconfiguration completion message to the RRC layer of the base station.

[0016] Under normal circumstances, after the UE receives the RRC reconfiguration message sent by the base station, the MAC layer of the base station will receive the MAC HARQ confirmation of all transport blocks containing the RRC reconfiguration message, the RLC layer of the base station will receive the RLC ARQ confirmation containing the RRC reconfiguration message, and the RRC layer of the base station will receive the RRC reconfiguration completion message, for a total of three UE confirmations to the base station. However, when the wireless signal is poor or there is strong interference, the RRC reconfiguration message, MAC HARQ confirmation, RLC ARQ confirmation and RRC reconfiguration completion message may be lost, and there may be the following scenarios.

[0017] Scenario 1: The UE does not receive the RRC reconfiguration message sent by the base station.

[0018] Scenario 2: The UE receives an RRC reconfiguration message sent by the base station, but the base station does not receive a MAC HARQ confirmation of the transport block containing the RRC reconfiguration message.

[0019] Scenario 3: The UE receives an RRC reconfiguration message from the base station, but the base station does not receive an RLC ARQ confirmation of the RLC SDU containing the RRC reconfiguration message.

[0020] Scenario 4: The UE receives the RRC reconfiguration message sent by the base station, but the UE fails to send the RRC reconfiguration complete message to the base station, or the RRC reconfiguration complete message is sent successfully but the base station does not receive the RRC reconfiguration complete message.

[0021] If the base station has sent an RRC reconfiguration message but has not received a confirmation from the UE when the RRC connection is reestablished (this means that the base station has not received one or more of the three confirmations), and the RRC reconfiguration message modifies the UE configuration that can be inherited during the RRC connection reestablishment process, the configuration between the base station and the UE may be inconsistent after the RRC reconfiguration. To illustrate this situation, we call the UE configuration before applying the RRC reconfiguration message configuration one, and the UE configuration after applying the RRC reconfiguration message configuration two. If the base station configures the UE based on configuration one after the RRC reconfiguration, or continues to use configuration one, the configurations of the UE and the base station will be inconsistent in scenario two. If the base station configures the UE based on configuration two, or continues to use configuration two, the configurations of the UE and the base station will be inconsistent in scenario one. Inconsistent configurations between the UE and the base station will cause the UE to not work properly after the RRC connection is reestablished. For example, if the radio bearer configuration is inconsistent, data or signaling transmission abnormalities will occur; if the measurement configuration is inconsistent, measurement report abnormalities will occur, affecting the subsequent switching process.

[0022] Although the base station can achieve configuration synchronization by using an RRC reconfiguration message carrying a full configuration information element in step S16, the current communication protocol does not forcibly stipulate that when the RRC connection is reestablished, if the base station has an unconfirmed RRC reconfiguration message, the full configuration is performed on the UE. The introduction of full configuration is mainly to solve the problem that the communication protocol version implemented by the target base station is lower than that of the source base station. If the communication protocol version implemented by the target base station is not lower than that of the source base station, the target base station usually does not perform full configuration. On the other hand, if the target base station does not have the context of the UE when the RRC connection is reestablished, there is no information element in the UE context response message to indicate whether the source base station has an unconfirmed RRC reconfiguration message, and the source base station cannot notify the target base station to retrieve the configuration in the UE context response message. There is a risk of inconsistency between the configuration and the UE configuration. Therefore, according to the current communication protocol, if the base station has an unconfirmed RRC reconfiguration message when the RRC connection is reestablished, the configurations of the UE and the base station may be inconsistent after the RRC connection is reestablished, and the UE cannot work normally after the RRC connection is reestablished. Summary of the invention

[0023] The technical problem to be solved by the present application is how to ensure that the configurations of the UE and the base station remain consistent after the RRC connection is reestablished, so that the UE can work normally after the RRC connection is reestablished.

[0024] In order to solve the above technical problems, the present application proposes a method for synchronous configuration after RRC connection reestablishment, comprising the following steps. Step S21: The UE sends an RRC connection reestablishment request message to the target base station. Step S22: The target base station has the context of the UE, and the target base station sends an RRC connection reestablishment message to the UE. Step S23: The UE sends an RRC connection reestablishment completion message to the target base station. Step S24: The target base station determines whether there is an RRC reconfiguration message that has been issued but not confirmed by the UE, hereinafter referred to as the old RRC reconfiguration message; if so, proceed to step S25; if not, proceed to step S25a. Step S25: The target base station releases the old UE configuration, regenerates a new UE configuration, and sends an RRC reconfiguration message containing a full configuration information element and a new UE configuration to the UE, hereinafter referred to as the new RRC reconfiguration message, and then proceeds to step S26. Step S25a: The target base station sends an RRC reconfiguration message to the UE, hereinafter referred to as the new RRC reconfiguration message, and then proceeds to step S26. Step S26: The UE processes the new RRC reconfiguration message and sends an RRC reconfiguration completion message corresponding to the new RRC reconfiguration message to the target base station, and at the same time resumes data transmission of the data radio bearer and the signaling radio bearer.

[0025] Further, in step S24, the RRC reconfiguration message that has been sent but not confirmed by the UE includes one or more of the following scenarios. Scenario A1: The target base station has previously sent an RRC reconfiguration message to the UE, hereinafter referred to as the old RRC reconfiguration message, the RLC layer of the target base station encapsulates the old RRC reconfiguration message into an RLC PDU, the MAC layer of the target base station encapsulates the RLC PDU into a MAC PDU and maps it to a transmission block for transmission, and the target base station does not receive the MAC HARQ confirmation of the transmission block containing the old RRC reconfiguration message. Scenario A2: The target base station has previously sent an RRC reconfiguration message to the UE, hereinafter referred to as the old RRC reconfiguration message, the RLC layer of the target base station encapsulates the old RRC reconfiguration message into multiple RLC PDUs, the MAC layer of the target base station encapsulates the multiple RLC PDUs into multiple MAC PDUs, and maps the multiple MAC PDUs to multiple transmission blocks for transmission, and the target base station does not receive the MAC HARQ confirmation of any one or more transmission blocks containing the old RRC reconfiguration message segments. Scenario A3: The target base station previously sent an RRC reconfiguration message to the UE, hereinafter referred to as the old RRC reconfiguration message, and the target base station did not receive the RLC ARQ confirmation of the RLC SDU containing the old RRC reconfiguration message. Scenario A4: The target base station previously sent an RRC reconfiguration message to the UE, hereinafter referred to as the old RRC reconfiguration message, and the target base station did not receive the RRC reconfiguration completion message corresponding to the old RRC reconfiguration message.

[0026] Furthermore, in step S24, if the RRC reconfiguration message sent by the target base station only modifies the UE configuration that cannot be inherited in the RRC connection reconstruction, and does not modify the UE configuration that can be inherited after the RRC connection reconstruction, the target base station does not determine whether there is an RRC reconfiguration message that has been sent but not confirmed by the UE, and directly proceeds to step S25a.

[0027] Optionally, the combination of step S24, step S25, and step S25a is performed before step S23 or before step S22.

[0028] The present application also proposes a method for synchronizing configuration of UE and network after RRC connection reestablishment, comprising the following steps. Step S31: UE sends an RRC connection reestablishment request message to the target base station. Step S32: The target base station does not have the context of the UE, and the target base station sends a UE context retrieval request message to the source base station, requesting the source base station to provide the context of the UE. Step S33: The source base station determines whether there is an RRC reconfiguration message that has been sent but not confirmed by the UE, hereinafter referred to as the old RRC reconfiguration message; if so, proceed to step S34; if not, proceed to step S34a. Step S34: The source base station adds a forced full configuration indication to the UE context retrieval response message to notify the target base station that there is an unconfirmed RRC reconfiguration message; the source base station sends the UE context retrieval response message containing the forced full configuration indication to the target base station, and then proceeds to step S35. Step S34a: The source base station sends a UE context retrieval response message to the target base station, and then proceeds to step S35. Step S35: The target base station sends an RRC connection reestablishment message to the UE. Step S36: The UE sends an RRC connection reestablishment completion message to the base station. Step S37: The target base station determines whether the UE context retrieval response message sent by the source base station contains a forced full configuration indication; if so, proceed to step S38; if not, proceed to step S38a. Step S38: The target base station releases the old UE configuration, regenerates a new UE configuration, and sends an RRC reconfiguration message containing a full configuration information element and a new UE configuration to the UE, hereinafter referred to as the new RRC reconfiguration message, and then proceeds to step S39. Step S38a: The target base station sends an RRC reconfiguration message to the UE, hereinafter referred to as the new RRC reconfiguration message, and then proceeds to step S39. Step S39: The UE processes the new RRC reconfiguration message, and sends an RRC reconfiguration completion message corresponding to the new RRC reconfiguration message to the target base station, and at the same time resumes data transmission of the data radio bearer and the signaling radio bearer.

[0029] Furthermore, in step S33, the RRC reconfiguration message that has been sent but not confirmed by the UE includes one or more of the following scenarios. Scenario B1: The source base station has previously sent an RRC reconfiguration message to the UE, hereinafter referred to as the old RRC reconfiguration message, the RLC layer of the source base station encapsulates the old RRC reconfiguration message into an RLC PDU, the MAC layer of the source base station encapsulates the RLC PDU into a MAC PDU and maps it to a transport block for transmission, and the source base station does not receive the MAC HARQ confirmation of the transport block containing the old RRC reconfiguration message. Scenario B2: The source base station has previously sent an RRC reconfiguration message to the UE, hereinafter referred to as the old RRC reconfiguration message, the RLC layer of the source base station segments and encapsulates the old RRC reconfiguration message into multiple RLC PDUs, the MAC layer of the source base station encapsulates the multiple RLC PDUs into multiple MAC PDUs, and maps the multiple MAC PDUs to multiple transport blocks for transmission, and the source base station does not receive the MAC HARQ confirmation of any one or more transport blocks containing the old RRC reconfiguration message segments. Scenario B3: The source base station previously sent an RRC reconfiguration message to the UE, hereinafter referred to as the old RRC reconfiguration message, and the source base station did not receive the RLC ARQ confirmation of the RLC SDU containing the old RRC reconfiguration message. Scenario B4: The source base station previously sent an RRC reconfiguration message to the UE, hereinafter referred to as the old RRC reconfiguration message, and the source base station did not receive the RRC reconfiguration completion message corresponding to the old RRC reconfiguration message.

[0030] Furthermore, in step S33, if the RRC reconfiguration message sent by the source base station only modifies the UE configuration that cannot be inherited in the RRC connection reconstruction, and does not modify the UE configuration that can be inherited after the RRC connection reconstruction, the source base station does not determine whether there is an RRC reconfiguration message that has been sent but not confirmed by the UE, and directly proceeds to step S34a.

[0031] Preferably, the combination of step S37, step S38 and step S38a is performed before step S36 or before step S35.

[0032] The present application also proposes a system for synchronous configuration of UE and network after RRC connection reconstruction, including an RRC connection reconstruction request message sending unit, an RRC connection reconstruction message sending unit, an RRC connection reconstruction completion message sending unit, an old RRC reconfiguration message confirmation check unit, a new RRC reconfiguration message sending unit 1, a new RRC reconfiguration message sending unit 2, and an RRC reconfiguration completion message sending unit. The RRC connection reconstruction request message sending unit is used by the UE to send an RRC connection reconstruction request message to the target base station. The RRC connection reconstruction message sending unit is used by the target base station to send an RRC connection reconstruction message to the UE, and the target base station has the context of the UE at this time. The RRC connection reconstruction completion message sending unit is used by the UE to send an RRC connection reconstruction completion message to the target base station. The old RRC reconfiguration message confirmation check unit is used by the target base station to determine whether there is an old RRC reconfiguration message that has been sent but not confirmed by the UE; if so, transfer to the new RRC reconfiguration message sending unit 1 for further processing; if not, transfer to the new RRC reconfiguration message sending unit 2 for further processing. The new RRC reconfiguration message sending unit 1 is used by the target base station to release the old UE configuration, regenerate the new UE configuration, and send a new RRC reconfiguration message containing the full configuration information element and the new UE configuration to the UE. The new RRC reconfiguration message sending unit 2 is used by the target base station to send a new RRC reconfiguration message to the UE. The RRC reconfiguration completion message sending unit is used by the UE to process the new RRC reconfiguration message, and send an RRC reconfiguration completion message corresponding to the new RRC reconfiguration message to the target base station, and at the same time resume the data transmission of the data radio bearer and the signaling radio bearer.

[0033] The present application also proposes a system for synchronous configuration of UE and network after RRC connection reconstruction, including an RRC connection reconstruction request message sending unit, a UE context retrieval request message sending unit, an old RRC reconfiguration message confirmation check unit, a UE context retrieval response message sending unit 1, a UE context retrieval response message sending unit 2, an RRC connection reconstruction message sending unit, an RRC connection reconstruction completion message sending unit, a forced full configuration indication confirmation check unit, a new RRC reconfiguration message sending unit 1, a new RRC reconfiguration message sending unit 2, and an RRC reconfiguration completion message sending unit. The RRC connection reconstruction request message sending unit is used by the UE to send an RRC connection reconstruction request message to the target base station. The UE context retrieval request message sending unit is used by the target base station to send a UE context retrieval request message to the source base station, at which time the target base station does not have the UE context. The old RRC reconfiguration message confirmation check unit is used by the source base station to determine whether there is an old RRC reconfiguration message that has been sent but not confirmed by the UE; if so, it is transferred to the UE context retrieval response message sending unit 1 for further processing; if not, it is transferred to the UE context retrieval response message sending unit 2 for further processing. The first unit for sending the UE context retrieval response message is used by the source base station to add a mandatory full configuration indication in the UE context retrieval response message, and the source base station sends the UE context retrieval response message containing the mandatory full configuration indication to the target base station. The second unit for sending the UE context retrieval response message is used by the source base station to send the UE context retrieval response message to the target base station. The RRC connection reconstruction message sending unit is used by the target base station to send the RRC connection reconstruction message to the UE. The RRC connection reconstruction completion message sending unit is used by the UE to send the RRC connection reconstruction completion message to the target base station. The mandatory full configuration indication confirmation check unit is used by the target base station to determine whether the UE context retrieval response message sent by the source base station contains a mandatory full configuration indication; if yes, transfer to the new RRC reconfiguration message sending unit one for further processing; if no, transfer to the new RRC reconfiguration message sending unit two for further processing. The new RRC reconfiguration message sending unit one is used by the target base station to release the old UE configuration, regenerate the new UE configuration, and send a new RRC reconfiguration message containing the full configuration information element and the new UE configuration to the UE. The new RRC reconfiguration message sending unit two is used by the target base station to send a new RRC reconfiguration message to the UE. The RRC reconfiguration complete message sending unit is used for the UE to process the new RRC reconfiguration message, and send an RRC reconfiguration complete message corresponding to the new RRC reconfiguration message to the target base station, and at the same time resume the data transmission of the data radio bearer and the signaling radio bearer.

[0034] The technical effect achieved by the present application is: when the UE reestablishes the RRC connection, if the target base station finds an unconfirmed old RRC reconfiguration message, the target base station enforces full configuration, thereby ensuring that the configurations of the UE and the target base station are consistent after the RRC connection is reestablished, and the UE can work normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a flowchart of the existing RRC connection reestablishment process.

[0036] Figure 2 It is a flowchart of embodiment 1 of the method for synchronous configuration after RRC connection reestablishment proposed in the present application.

[0037] Figure 3 It is a flowchart of Embodiment 2 of the method for synchronous configuration after RRC connection reestablishment proposed in the present application.

[0038] Figure 4 It is a structural diagram of embodiment 1 of the system for synchronous configuration after RRC connection reestablishment proposed in the present application.

[0039] Figure 5 It is a structural diagram of Embodiment 2 of the system for synchronous configuration after RRC connection reestablishment proposed in the present application.

[0040] Explanation of the reference numerals in the figure: RRC connection reconstruction request message sending unit 21, RRC connection reconstruction message sending unit 22, RRC connection reconstruction completion message sending unit 23, old RRC reconfiguration message confirmation checking unit 24, new RRC reconfiguration message sending unit one 25, new RRC reconfiguration message sending unit two 25a, RRC reconfiguration completion message sending unit 26, RRC connection reconstruction request message sending unit 31, retrieval UE context request message sending unit 32, old RRC reconfiguration message confirmation checking unit 33, retrieval UE context response message sending unit one 34, retrieval UE context response message sending unit two 34a, RRC connection reconstruction message sending unit 35, RRC connection reconstruction completion message sending unit 36, forced full configuration indication confirmation checking unit 37, new RRC reconfiguration message sending unit one 38, new RRC reconfiguration message sending unit two 38a, RRC reconfiguration completion message sending unit 39. DETAILED DESCRIPTION

[0041] See also Figure 2 , Embodiment 1 of the method for synchronously configuring UE and network after RRC connection reestablishment proposed in the present application includes the following steps. The illustrated embodiment 1 is applicable to the scenario where the target base station has the context of the UE, wherein the names of various messages in the 4G and 5G mobile communication systems are consistent with the records of steps S11 to S7.

[0042] Step S21: The UE sends an RRC connection reestablishment request message to the target base station.

[0043] Step S22: The target base station has the context of the UE, and the target base station sends an RRC connection reestablishment message to the UE.

[0044] Step S23: The UE sends an RRC connection reestablishment completion message to the target base station.

[0045] Step S24: The target base station determines whether there is an RRC reconfiguration message that has been sent but not confirmed by the UE (hereinafter referred to as the old RRC reconfiguration message). If yes, proceed to step S25. If not, proceed to step S25a.

[0046] In this step, the RRC reconfiguration message is not confirmed by the UE, including one or more of the following scenarios.

[0047] Scenario A1: The target base station previously sent an RRC reconfiguration message (hereinafter referred to as the old RRC reconfiguration message) to the UE. When the RLC layer of the target base station did not segment the old RRC reconfiguration message - that is, the PDCP PDU containing the RRC reconfiguration message was encapsulated into an RLC PDU by the RLC layer of the target base station, and encapsulated into a MAC PDU by the MAC layer of the target base station and mapped to a transport block for transmission, the target base station did not receive the MAC HARQ confirmation of the transport block containing the old RRC reconfiguration message.

[0048] Scenario A2: The target base station has previously sent an RRC reconfiguration message (hereinafter referred to as the old RRC reconfiguration message) to the UE. When the RLC layer of the target base station segments the old RRC reconfiguration message - that is, the PDCP PDU containing the RRC reconfiguration message is encapsulated into multiple RLC PDUs by the RLC layer of the target base station, and the MAC layer of the target base station encapsulates each RLC PDU into a MAC PDU, and maps the MAC PDU to multiple transport blocks for transmission, the target base station does not receive the MAC HARQ confirmation of any one or more transport blocks containing the old RRC reconfiguration message segments.

[0049] Scenario A3: The target base station previously sent an RRC reconfiguration message (hereinafter referred to as the old RRC reconfiguration message) to the UE, and the target base station did not receive the RLC ARQ confirmation of the RLC SDU containing the old RRC reconfiguration message.

[0050] Scenario A4: The target base station previously sent an RRC reconfiguration message (hereinafter referred to as the old RRC reconfiguration message) to the UE, and the target base station did not receive the RRC reconfiguration completion message corresponding to the old RRC reconfiguration message.

[0051] Preferably, in step S24, if the RRC reconfiguration message sent by the target base station only modifies the UE configuration (such as physical layer configuration) that cannot be inherited in the RRC connection reconstruction, and does not modify the UE configuration that can be inherited after the RRC connection reconstruction (such as wireless bearer configuration, measurement configuration), the target base station no longer determines whether the RRC reconfiguration message is not confirmed by the UE, and directly proceeds to step S25a.

[0052] Step S25: The target base station releases the old UE configuration, regenerates a new UE configuration, and sends an RRC reconfiguration message (hereinafter referred to as the new RRC reconfiguration message) containing the full configuration information element and the new UE configuration to the UE, and then proceeds to step S26.

[0053] Step S25a: The target base station sends an RRC reconfiguration message (hereinafter referred to as the new RRC reconfiguration message) to the UE according to the existing communication protocol, and then proceeds to step S26.

[0054] Step S26: The UE processes the new RRC reconfiguration message according to the existing communication protocol, and sends an RRC reconfiguration completion message corresponding to the new RRC reconfiguration message to the target base station, and resumes data transmission of the data radio bearer (DRB) and the signaling radio bearer SRB 2 (if SRB4 is configured, this also includes SRB 4). Before the UE receives the RRC reconfiguration message, these radio bearers are suspended and data transmission is not possible.

[0055] If the process proceeds from step S25 to step S26, the RRC reconfiguration message includes a full configuration information element. The configurations of the data radio bearer (DRB) and the signaling radio bearer SRB 2 (including SRB 4 if SRB4 is configured) before the RRC connection is reestablished are invalidated, and the UE reconfigures the data radio bearer and the signaling radio bearer according to the new UE configuration in the RRC reconfiguration message, and resumes data transmission.

[0056] Optionally, the combination of step S24, step S25, and step S25a is performed before step S23 or before step S22.

[0057] See also Figure 3 , Embodiment 2 of the method for synchronously configuring UE and network after RRC connection reestablishment proposed in the present application includes the following steps. The illustrated embodiment 2 is applicable to a scenario where the target base station does not have the context of the UE, wherein the names of various messages in the 4G and 5G mobile communication systems are consistent with the records of steps S11 to S7.

[0058] Step S31: The UE sends an RRC connection reestablishment request message to the target base station.

[0059] Step S32: the target base station does not have the context of the UE, and the target base station sends a UE context retrieval request message to the source base station, requesting the source base station to provide the context of the UE.

[0060] Step S33: The source base station determines whether there is an RRC reconfiguration message that has been sent but not confirmed by the UE (hereinafter referred to as the old RRC reconfiguration message). If yes, go to step S34. If not, go to step S34a.

[0061] In this step, the RRC reconfiguration message is not confirmed by the UE, including one or more of the following scenarios.

[0062] Scenario B1: The source base station has previously sent an RRC reconfiguration message (hereinafter referred to as the old RRC reconfiguration message) to the UE. When the RLC layer of the source base station does not segment the old RRC reconfiguration message - that is, the PDCP PDU containing the RRC reconfiguration message is encapsulated into an RLC PDU by the RLC layer of the source base station, and is encapsulated into a MAC PDU by the MAC layer of the source base station and mapped to a transmission block for transmission, the source base station does not receive the MAC HARQ confirmation of the transmission block containing the old RRC reconfiguration message.

[0063] Scenario B2: The source base station has previously sent an RRC reconfiguration message (hereinafter referred to as the old RRC reconfiguration message) to the UE. When the RLC layer of the source base station segments the old RRC reconfiguration message - that is, the PDCP PDU containing the RRC reconfiguration message is encapsulated into multiple RLC PDUs by the RLC layer of the source base station, and the MAC layer of the source base station encapsulates each RLC PDU into a MAC PDU, and maps the MAC PDU to multiple transmission blocks for transmission, the source base station does not receive the MAC HARQ confirmation of any one or more transmission blocks containing the old RRC reconfiguration message segments.

[0064] Scenario B3: The source base station previously sent an RRC reconfiguration message (hereinafter referred to as the old RRC reconfiguration message) to the UE, and the source base station did not receive the RLC ARQ confirmation of the RLC SDU containing the old RRC reconfiguration message.

[0065] Scenario B4: The source base station previously sent an RRC reconfiguration message (hereinafter referred to as the old RRC reconfiguration message) to the UE, and the source base station did not receive the RRC reconfiguration completion message corresponding to the old RRC reconfiguration message.

[0066] Preferably, in step S33, if the RRC reconfiguration message sent by the source base station only modifies the UE configuration that cannot be inherited in the RRC connection reconstruction (such as the physical layer configuration), and does not modify the UE configuration that can be inherited after the RRC connection reconstruction (such as the wireless bearer configuration, the measurement configuration), the source base station no longer determines whether the RRC reconfiguration message is not confirmed by the UE, and directly proceeds to step S34a.

[0067] Step S34: The source base station adds an indication, such as a forced full configuration indication, to the retrieve UE context response message to notify the target base station that there is an unconfirmed RRC reconfiguration message. The source base station sends the retrieve UE context response message including the forced full configuration indication to the target base station, and then proceeds to step S35.

[0068] Step S34a: The source base station sends a UE context retrieval response message to the target base station according to the existing communication protocol, and then proceeds to step S35.

[0069] Step S35: The target base station sends an RRC connection reestablishment message to the UE.

[0070] Step S36: The UE sends an RRC connection reestablishment completion message to the base station.

[0071] Step S37: The target base station determines whether the UE context search response message sent by the source base station contains a mandatory full configuration indication. If yes, proceed to step S38. If no, proceed to step S38a.

[0072] Step S38: The target base station releases the old UE configuration, regenerates a new UE configuration, and sends an RRC reconfiguration message (hereinafter referred to as the new RRC reconfiguration message) containing a full configuration information element and the new UE configuration to the UE, and then proceeds to step S39.

[0073] Step S38a: The target base station sends an RRC reconfiguration message (hereinafter referred to as the new RRC reconfiguration message) to the UE according to the existing communication protocol, and then proceeds to step S39.

[0074] Step S39: The UE processes the new RRC reconfiguration message according to the existing communication protocol, and sends an RRC reconfiguration completion message corresponding to the new RRC reconfiguration message to the target base station, and simultaneously resumes data transmission of DRB and SRB2 (if SRB4 is configured, SRB4 is also included here).

[0075] If the process proceeds from step S38 to step S39, the RRC reconfiguration message includes a full configuration information element. The configurations of the data radio bearer (DRB) and the signaling radio bearer SRB 2 (including SRB 4 if SRB4 is configured) before the RRC connection is reestablished are invalidated, and the UE reconfigures the data radio bearer and the signaling radio bearer according to the new UE configuration in the RRC reconfiguration message, and resumes data transmission.

[0076] Optionally, the combination of step S37, step S38, and step S38a is performed before step S36 or before step S35.

[0077] See also Figure 4The embodiment 1 of the system for synchronously configuring the UE and the network after RRC connection reestablishment proposed in the present application includes an RRC connection reestablishment request message sending unit 21, an RRC connection reestablishment message sending unit 22, an RRC connection reestablishment completion message sending unit 23, an old RRC reconfiguration message confirmation check unit 24, a new RRC reconfiguration message sending unit 1 25, a new RRC reconfiguration message sending unit 2 25a, and an RRC reconfiguration completion message sending unit 26. The embodiment 1 shown is applicable to the scenario where the target base station has the context of the UE, Figure 4 The system shown corresponds to Figure 2 The method shown.

[0078] The RRC connection reestablishment request message sending unit 21 is used for the UE to send an RRC connection reestablishment request message to a target base station.

[0079] The RRC connection reestablishment message sending unit 22 is used for the target base station to send an RRC connection reestablishment message to the UE. At this time, the target base station has the context of the UE.

[0080] The RRC connection reestablishment completion message sending unit 23 is used for the UE to send an RRC connection reestablishment completion message to the target base station.

[0081] The old RRC reconfiguration message confirmation checking unit 24 is used by the target base station to determine whether there is an old RRC reconfiguration message that has been sent but not confirmed by the UE. If yes, it is transferred to the new RRC reconfiguration message sending unit 1 25 for further processing. If no, it is transferred to the new RRC reconfiguration message sending unit 2 25a for further processing.

[0082] The new RRC reconfiguration message sending unit 25 is used for the target base station to release the old UE configuration, regenerate the new UE configuration, and send a new RRC reconfiguration message including the full configuration information element and the new UE configuration to the UE.

[0083] The new RRC reconfiguration message sending unit 25a is used for the target base station to send a new RRC reconfiguration message to the UE.

[0084] The RRC reconfiguration complete message sending unit 26 is used for the UE to process the new RRC reconfiguration message, and send an RRC reconfiguration complete message corresponding to the new RRC reconfiguration message to the target base station, and at the same time resume the data transmission of DRB, SRB2, and SRB4 (if SRB4 is configured).

[0085] See also Figure 5The second embodiment of the system for synchronously configuring UE and network after RRC connection reestablishment proposed in the present application includes an RRC connection reestablishment request message sending unit 31, a UE context retrieval request message sending unit 32, an old RRC reconfiguration message confirmation check unit 33, a UE context retrieval response message sending unit 1 34, a UE context retrieval response message sending unit 2 34a, an RRC connection reestablishment message sending unit 35, an RRC connection reestablishment completion message sending unit 36, a forced full configuration indication confirmation check unit 37, a new RRC reconfiguration message sending unit 1 38, a new RRC reconfiguration message sending unit 2 38a, and an RRC reconfiguration completion message sending unit 39. The second embodiment shown is applicable to the scenario where the target base station does not have the context of the UE. Figure 5 The system shown corresponds to Figure 3 The method shown.

[0086] The RRC connection reestablishment request message sending unit 31 is used for the UE to send an RRC connection reestablishment request message to a target base station.

[0087] The UE context retrieval request message sending unit 32 is used for the target base station to send a UE context retrieval request message to the source base station. At this time, the target base station does not have the UE context.

[0088] The old RRC reconfiguration message confirmation checking unit 33 is used by the source base station to determine whether there is an old RRC reconfiguration message that has been sent but not confirmed by the UE. If yes, it is transferred to the retrieval UE context response message sending unit 1 34 to continue processing. If no, it is transferred to the retrieval UE context response message sending unit 2 34a to continue processing.

[0089] The UE context retrieval response message sending unit 34 is used for the source base station to add a mandatory full configuration indication in the UE context retrieval response message, and the source base station sends the UE context retrieval response message including the mandatory full configuration indication to the target base station.

[0090] The second UE context retrieval response message sending unit 34a is used for the source base station to send a UE context retrieval response message to the target base station.

[0091] The RRC connection reestablishment message sending unit 35 is used for the target base station to send an RRC connection reestablishment message to the UE.

[0092] The RRC connection reestablishment completion message sending unit 36 ​​is used for the UE to send an RRC connection reestablishment completion message to the target base station.

[0093] The mandatory full configuration indication confirmation checking unit 37 is used for the target base station to determine whether the UE context retrieval response message sent by the source base station contains a mandatory full configuration indication. If yes, it is transferred to the new RRC reconfiguration message sending unit 1 38 for further processing. If no, it is transferred to the new RRC reconfiguration message sending unit 2 38a for further processing.

[0094] The new RRC reconfiguration message sending unit 38 is used for the target base station to release the old UE configuration, regenerate the new UE configuration, and send a new RRC reconfiguration message including the full configuration information element and the new UE configuration to the UE.

[0095] The new RRC reconfiguration message sending unit 2 38a is used for the target base station to send a new RRC reconfiguration message to the UE.

[0096] The RRC reconfiguration complete message sending unit 39 is used for the UE to process the new RRC reconfiguration message, and send an RRC reconfiguration complete message corresponding to the new RRC reconfiguration message to the target base station, and at the same time resume the data transmission of DRB, SRB2, and SRB4 (if SRB4 is configured).

[0097] This application is used to ensure configuration synchronization between the UE and the network by forcing the target base station to execute full configuration after the RRC connection is reestablished, if the base station cannot determine the UE configuration that the UE can continue to use before the RRC connection is reestablished. In the technical solution proposed in this application, the target base station releases the old UE configuration, then generates a new UE configuration, and sends the full configuration information element and the new UE configuration to the UE in a new RRC reconfiguration message. After the UE receives the new RRC reconfiguration message containing the full configuration information element, it first releases the old UE configuration according to the existing communication protocol, and then completely uses the new UE configuration, thereby achieving configuration synchronization between the target base station and the UE, and ensuring the normal operation of the UE after the RRC connection is reestablished.

[0098] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should all be included in the protection scope of the present application.

Claims

1. A method for synchronization configuration after RRC connection reestablishment, characterized in that: The method comprises the following steps: Step S21: The UE sends an RRC connection reestablishment request message to the target base station; Step S22: The target base station has the context of the UE, and the target base station sends an RRC connection reestablishment message to the UE; Step S23: The UE sends an RRC connection reestablishment completion message to the target base station; Step S24: The target base station determines whether there is an RRC reconfiguration message that has been sent but not confirmed by the UE, hereinafter referred to as an old RRC reconfiguration message; If yes, go to step S25; if no, go to step S25a; Step S25: the target base station releases the old UE configuration, regenerates a new UE configuration, and sends an RRC reconfiguration message including a full configuration information element and the new UE configuration to the UE, hereinafter referred to as the new RRC reconfiguration message, and then proceeds to step S26; Step S25a: The target base station sends an RRC reconfiguration message to the UE, hereinafter referred to as a new RRC reconfiguration message, and then proceeds to step S26; Step S26: The UE processes the new RRC reconfiguration message and sends an RRC reconfiguration completion message corresponding to the new RRC reconfiguration message to the target base station, and at the same time resumes data transmission of the data radio bearer and the signaling radio bearer.

2. The method for synchronous configuration after RRC connection reestablishment according to claim 1, characterized in that: In step S24, the RRC reconfiguration message that has been sent but not confirmed by the UE includes one or more of the following scenarios; Scenario A1: The target base station previously sent an RRC reconfiguration message to the UE, hereinafter referred to as the old RRC reconfiguration message. The RLC layer of the target base station encapsulates the old RRC reconfiguration message into an RLC PDU. The MAC layer of the target base station encapsulates the RLC PDU into a MAC PDU and maps it to a transport block for transmission. The target base station does not receive the MAC HARQ confirmation of the transport block containing the old RRC reconfiguration message. Scenario A2: The target base station previously sent an RRC reconfiguration message to the UE, hereinafter referred to as the old RRC reconfiguration message, the RLC layer of the target base station encapsulates the old RRC reconfiguration message into multiple RLC PDUs, the MAC layer of the target base station encapsulates the multiple RLC PDUs into multiple MAC PDUs, and maps the multiple MAC PDUs to multiple transport blocks for transmission, and the target base station does not receive a MAC HARQ confirmation of any one or more transport blocks containing the old RRC reconfiguration message segments; Scenario A3: The target base station previously sent an RRC reconfiguration message to the UE, hereinafter referred to as the old RRC reconfiguration message, and the target base station did not receive the RLC ARQ confirmation of the RLC SDU containing the old RRC reconfiguration message; Scenario A4: The target base station previously sent an RRC reconfiguration message to the UE, hereinafter referred to as the old RRC reconfiguration message, and the target base station did not receive the RRC reconfiguration completion message corresponding to the old RRC reconfiguration message.

3. The method for synchronous configuration after RRC connection reestablishment according to claim 1, characterized in that: In the step S24, if the RRC reconfiguration message sent by the target base station only modifies the UE configuration that cannot be inherited in the RRC connection reconstruction, and does not modify the UE configuration that can be inherited after the RRC connection reconstruction, the target base station does not determine whether there is an RRC reconfiguration message that has been sent but not confirmed by the UE, and directly proceeds to step S25a.

4. The method for synchronous configuration after RRC connection reestablishment according to claim 1, characterized in that: The combination of step S24, step S25, and step S25a is changed to be performed before step S23 or before step S22.

5. A method for UE and network synchronization configuration after RRC connection reestablishment, characterized in that: The method comprises the following steps: Step S31: The UE sends an RRC connection reestablishment request message to the target base station; Step S32: the target base station does not have the context of the UE, and the target base station sends a UE context retrieval request message to the source base station, requesting the source base station to provide the context of the UE; Step S33: The source base station determines whether there is an RRC reconfiguration message that has been sent but not confirmed by the UE, hereinafter referred to as an old RRC reconfiguration message; If yes, go to step S34; If not, go to step S34a; Step S34: the source base station adds a forced full configuration indication in the UE context retrieval response message to notify the target base station that there is an unconfirmed RRC reconfiguration message; The source base station sends a retrieve UE context response message including a mandatory full configuration indication to the target base station, and then proceeds to step S35; Step S34a: The source base station sends a UE context retrieval response message to the target base station, and then proceeds to step S35; Step S35: The target base station sends an RRC connection reestablishment message to the UE; Step S36: The UE sends an RRC connection reestablishment completion message to the base station; Step S37: The target base station determines whether the UE context retrieval response message sent by the source base station contains a mandatory full configuration indication; if yes, proceed to step S38; If not, go to step S38a; Step S38: the target base station releases the old UE configuration, regenerates a new UE configuration, and sends an RRC reconfiguration message including a full configuration information element and the new UE configuration to the UE, hereinafter referred to as the new RRC reconfiguration message, and then proceeds to step S39; Step S38a: The target base station sends an RRC reconfiguration message to the UE, hereinafter referred to as a new RRC reconfiguration message, and then proceeds to step S39; Step S39: The UE processes the new RRC reconfiguration message, and sends an RRC reconfiguration completion message corresponding to the new RRC reconfiguration message to the target base station, and at the same time resumes data transmission of the data radio bearer and the signaling radio bearer.

6. The method for synchronous configuration after RRC connection reestablishment according to claim 5, characterized in that: In step S33, the RRC reconfiguration message that has been sent but not confirmed by the UE includes one or more of the following scenarios; Scenario B1: The source base station previously sent an RRC reconfiguration message to the UE, hereinafter referred to as the old RRC reconfiguration message. The RLC layer of the source base station encapsulates the old RRC reconfiguration message into an RLC PDU. The MAC layer of the source base station encapsulates the RLC PDU into a MAC PDU and maps it to a transport block for transmission. The source base station does not receive the MAC HARQ confirmation of the transport block containing the old RRC reconfiguration message. Scenario B2: The source base station previously sent an RRC reconfiguration message to the UE, hereinafter referred to as the old RRC reconfiguration message. The RLC layer of the source base station segments and encapsulates the old RRC reconfiguration message into multiple RLC PDUs. The MAC layer of the source base station encapsulates the multiple RLC PDUs into multiple MAC PDUs, and maps the multiple MAC PDUs to multiple transport blocks for transmission. The source base station does not receive a MAC HARQ confirmation of any one or more transport blocks containing the old RRC reconfiguration message segments. Scenario B3: The source base station previously sent an RRC reconfiguration message to the UE, hereinafter referred to as the old RRC reconfiguration message, and the source base station did not receive the RLC ARQ confirmation of the RLC SDU containing the old RRC reconfiguration message; Scenario B4: The source base station previously sent an RRC reconfiguration message to the UE, hereinafter referred to as the old RRC reconfiguration message, and the source base station did not receive the RRC reconfiguration completion message corresponding to the old RRC reconfiguration message.

7. The method for synchronous configuration after RRC connection reestablishment according to claim 5, characterized in that: In the step S33, if the RRC reconfiguration message sent by the source base station only modifies the UE configuration that cannot be inherited in the RRC connection reconstruction, and does not modify the UE configuration that can be inherited after the RRC connection reconstruction, the source base station does not determine whether there is an RRC reconfiguration message that has been sent but not confirmed by the UE, and directly proceeds to step S34a.

8. The method for synchronous configuration after RRC connection reestablishment according to claim 5, characterized in that: The combination of step S37, step S38, and step S38a is changed to be performed before step S36 or before step S35.

9. A system for synchronous configuration of UE and network after RRC connection reestablishment, characterized in that: It includes an RRC connection reconstruction request message sending unit, an RRC connection reconstruction message sending unit, an RRC connection reconstruction completion message sending unit, an old RRC reconfiguration message confirmation check unit, a new RRC reconfiguration message sending unit 1, a new RRC reconfiguration message sending unit 2, and an RRC reconfiguration completion message sending unit; The RRC connection reestablishment request message sending unit is used for the UE to send an RRC connection reestablishment request message to the target base station; The RRC connection reestablishment message sending unit is used for the target base station to send an RRC connection reestablishment message to the UE, and at this time the target base station has the context of the UE; The RRC connection reestablishment completion message sending unit is used for the UE to send an RRC connection reestablishment completion message to the target base station; The old RRC reconfiguration message confirmation checking unit is used for the target base station to determine whether there is an old RRC reconfiguration message that has been sent but not confirmed by the UE; if so, transfer to the new RRC reconfiguration message sending unit 1 for further processing; if not, transfer to the new RRC reconfiguration message sending unit 2 for further processing; The new RRC reconfiguration message sending unit 1 is used for the target base station to release the old UE configuration, regenerate the new UE configuration, and send a new RRC reconfiguration message including the full configuration information element and the new UE configuration to the UE; The new RRC reconfiguration message sending unit 2 is used for the target base station to send a new RRC reconfiguration message to the UE; The RRC reconfiguration complete message sending unit is used for the UE to process the new RRC reconfiguration message, and send an RRC reconfiguration complete message corresponding to the new RRC reconfiguration message to the target base station, and at the same time resume the data transmission of the data radio bearer and the signaling radio bearer.

10. A system for synchronous configuration of UE and network after RRC connection reestablishment, characterized in that: It includes an RRC connection reestablishment request message sending unit, a UE context retrieval request message sending unit, an old RRC reconfiguration message confirmation checking unit, a UE context retrieval response message sending unit 1, a UE context retrieval response message sending unit 2, an RRC connection reestablishment message sending unit, an RRC connection reestablishment completion message sending unit, a forced full configuration indication confirmation checking unit, a new RRC reconfiguration message sending unit 1, a new RRC reconfiguration message sending unit 2, and an RRC reconfiguration completion message sending unit; The RRC connection reestablishment request message sending unit is used for the UE to send an RRC connection reestablishment request message to the target base station; The UE context retrieval request message sending unit is used for the target base station to send a UE context retrieval request message to the source base station, when the target base station does not have the UE context; The old RRC reconfiguration message confirmation checking unit is used for the source base station to determine whether there is an old RRC reconfiguration message that has been sent but not confirmed by the UE; If yes, proceed to the UE context retrieval response message sending unit 1 to continue processing; If not, proceed to the second unit for sending the UE context response message to continue processing; The first UE context retrieval response message sending unit is used for the source base station to add a mandatory full configuration indication in the UE context retrieval response message, and the source base station sends the UE context retrieval response message including the mandatory full configuration indication to the target base station; The second UE context retrieval response message sending unit is used for the source base station to send a UE context retrieval response message to the target base station; The RRC connection reestablishment message sending unit is used for sending an RRC connection reestablishment message to the UE by the target base station; The RRC connection reestablishment completion message sending unit is used for the UE to send an RRC connection reestablishment completion message to the target base station; The mandatory full configuration indication confirmation checking unit is used for the target base station to determine whether the UE context retrieval response message sent by the source base station contains a mandatory full configuration indication; if so, transfer to a new RRC reconfiguration message sending unit 1 for further processing; If not, transfer to the new RRC reconfiguration message sending unit 2 to continue processing; The new RRC reconfiguration message sending unit 1 is used for the target base station to release the old UE configuration, regenerate the new UE configuration, and send a new RRC reconfiguration message including the full configuration information element and the new UE configuration to the UE; The new RRC reconfiguration message sending unit 2 is used for the target base station to send a new RRC reconfiguration message to the UE; The RRC reconfiguration complete message sending unit is used for the UE to process the new RRC reconfiguration message, and send an RRC reconfiguration complete message corresponding to the new RRC reconfiguration message to the target base station, and at the same time resume the data transmission of the data radio bearer and the signaling radio bearer.

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