CN116530205A

CN116530205A - Condition changing method and device for auxiliary primary cell

Info

Publication number: CN116530205A
Application number: CN202180076825.XA
Authority: CN
Inventors: 董柏序; 姚琴波; 戴振华
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-06-07
Filing date: 2021-06-07
Publication date: 2023-08-01
Also published as: WO2022256982A1

Abstract

The application relates to the technical field of wireless communication and discloses a method and a device for changing conditions of an auxiliary main cell. The method comprises the following steps: receiving a first radio link control (RRC) connection reconfiguration message, wherein the message carries synchronization information of candidate auxiliary primary cells (PSCells) and triggering condition information of a condition auxiliary primary cell changing (CPC); sending a first RRC reconfiguration complete message; in the CPC executing process, receiving a second RRC connection reconfiguration message, wherein the message carries cell configuration information; sending a second RRC reconfiguration complete message; and when the second RRC connection reconfiguration message carries synchronization information of a target PSCell, initiating a random access process to the target PSCell. By adopting the scheme, the problem of parameter opposite flushing caused by receiving the second RRC connection reconfiguration message in the executing process of the CPC by the terminal equipment can be solved, the CPC flow is actively interrupted, the second RRC connection reconfiguration message is responded in time, and different uplink messages are sent according to the cell information carried by the second RRC connection reconfiguration message to indicate whether the switching of the PSCell is successful or not.

Description

Condition changing method and device for auxiliary primary cell

Technical Field

The embodiment of the application relates to the field of communication, in particular to a method and a device for changing the conditions of an auxiliary primary cell.

Background

Today's wireless communication networks are widely deployed in life to provide diverse communication services such as voice, video, packet data, messaging, broadcast, and so on. Based on different wireless application scenarios and the requirement of multiple services, wireless access technologies and wireless communication networks can develop in a diversified manner, and coexist and complement in a longer period of time. The service networks and the wireless access technologies suitable for different wireless application scenes form a multi-system communication network which is seamlessly covered and can provide good service experience, and thus, a user is in an environment covered by the multi-system communication network.

Taking mobile communication technology networks as examples, long term evolution (Long Term Evolution, LTE) networks and New Radio (NR) networks are faced with long term coexistence. In order to realize interconnection between communication network systems and improve the radio resource utilization rate of the whole mobile network system, a Dual-Connectivity (DC) technology is introduced to support the terminal to connect two cells at the same time, thereby increasing throughput of a single user. The two cells each correspond to a primary cell group (Master Cell group, MCG) and a secondary cell group (Secondary Cell group, SCG), wherein the cell group where the cell where the terminal initiates random access first is the primary cell group.

When a terminal moves, it is necessary to perform handover between cells. To further enhance the mobility of the terminal, conditional switching techniques are introduced to enable the reporting capability of the terminal to support conditional switching. Namely, when the terminal receives the configuration of conditional switching issued by the base station corresponding to the candidate cell, the terminal does not immediately execute switching action, continues to measure and evaluate the candidate cell, and when the switching condition is met, selects the corresponding cell for random access. For the conditional switching process of MCG, it is generally called conditional switching (Conditional Handover, CHO); for SCG, it is generally called a condition change (Conditional PSCell Change, CPC) of the secondary primary cell.

In the prior art, in a multi-system dual-connection scenario, the execution process of conditional auxiliary main cell change includes random access, the flow of random access occupies a long time, and because of the issuing sequence of air interface messages, the terminal still receives the configuration information of the source cell after performing auxiliary main cell switch. This may lead to erroneous superposition of terminal side configuration information, and the terminal re-establishes MCG, affecting service continuity. Therefore, it is necessary to study and improve a conditional auxiliary primary cell change method, avoid unnecessary MCG reconstruction, and improve the communication experience of the user.

Disclosure of Invention

The embodiment of the application provides a method and a device for changing the conditions of an auxiliary main cell, which are used for avoiding unnecessary MCG reconstruction caused by the wrong use of configuration information when a CPC flow collides with a radio link connection RRC configuration message issued by a base station, so that the service quality and the communication experience of a user are ensured.

In a first aspect, embodiments of the present application provide a method of wireless communication, the method being executable by a wireless communication device. The method comprises the following steps: receiving a first radio link control (RRC) connection reconfiguration message, wherein the first RRC connection reconfiguration message carries synchronization information of candidate auxiliary main cells and triggering condition information of a condition auxiliary main cell change (CPC); transmitting a first RRC reconfiguration complete message, wherein the first RRC reconfiguration complete message is used for responding to the first RRC connection reconfiguration message; receiving a second RRC connection reconfiguration message from the main cell in the process of executing the conditional auxiliary main cell change, wherein the second RRC connection reconfiguration message carries cell configuration information; sending a second RRC reconfiguration complete message to the primary cell, wherein the second RRC reconfiguration complete message is used for responding to the second RRC connection reconfiguration message; and when the cell configuration information carried by the second RRC connection reconfiguration message comprises the synchronization information of the target auxiliary main cell, initiating a random access process to the target auxiliary main cell. In one possible implementation manner, the cell configuration information carried by the message may be determined to be the synchronization information of the target secondary primary cell through the information (such as the secondary cell group number) indicating the secondary primary cell and the ReconfigurationWithSync field in the message.

Based on the method, the terminal interrupts the CPC flow in progress, preferentially responds to the second RRC connection reconfiguration message carrying the configuration information of the target auxiliary main cell, and avoids the possible configuration parameter retention failure, cell group reconstruction and service interruption caused by the reconstruction of the main cell group or the simple superposition of the configuration information carried by the second RRC connection reconfiguration message which are caused by not responding to the second RRC connection reconfiguration message.

As another possible implementation manner, the terminal sends a secondary cell group failure information message to the primary cell when the cell configuration information carried by the second RRC connection reconfiguration message does not include synchronization information of the target secondary primary cell.

Based on the method, the terminal actively initiates a secondary cell group failure flow when judging that the RRC connection reconfiguration message does not carry the synchronous information of the target secondary primary cell by interrupting the CPC flow in progress, and the network is required to carry out cell assignment and reconstruction of the secondary cell group on the terminal, so that the cell group reconstruction caused by the release of the terminal context by the network is prevented.

In a specific implementation of the above method, the terminal receives a second RRC connection reconfiguration message from the primary cell in the performing condition-assisted primary cell change procedure, including: and before sending a third RRC reconfiguration complete message to the main cell, receiving the second RRC connection reconfiguration message, wherein the third RRC reconfiguration complete message is used for indicating the end of the conditional auxiliary main cell changing flow.

Or in another possible implementation manner, the terminal receives a second RRC connection reconfiguration message from the primary cell in the process of performing the conditional auxiliary primary cell change, including: and receiving the second RRC connection reconfiguration message in a first time period after the third RRC reconfiguration completion message is sent to the main cell. The first time period is less than the time consumption of the primary cell to receive the RRC reconfiguration complete message and issue a new RRC configuration, and may be a fixed value. In one possible implementation, the range of values is 30 to 50 milliseconds.

In the technical scheme, the terminal responds to the received second RRC connection reconfiguration message by interrupting the CPC flow in progress, and actively triggers the failure flow of the secondary cell group when judging that the message does not carry the synchronization information of the target secondary primary cell. And the service is interrupted because the terminal does not respond to the message and the reconstruction of the main cell group is avoided. The terminal can also inform the network of the failure of the establishment of the auxiliary cell group through the auxiliary cell group establishment failure message, and the network is required to participate in the reconstruction of the auxiliary cell group, thereby helping to realize the access of a new auxiliary main cell.

In a second aspect, embodiments of the present application provide another method of wireless communication, the method being executable by a wireless communication device. The method comprises the following steps: receiving a first RRC connection reconfiguration message, wherein the message carries the synchronization information of the candidate auxiliary main cell and the triggering condition information of the condition auxiliary main cell change; transmitting a first RRC reconfiguration complete message, wherein the message is used for responding to the first RRC connection reconfiguration message; before executing the CPC process, sending CPC execution notification information for notifying the network terminal to start the CPC process; receiving a CPC execution response message, wherein the CPC execution response message is used for responding to the CPC execution notification message; and after receiving the CPC execution response message, starting a CPC flow.

In the technical scheme, before the CPC flow is started, the terminal informs the network of the operation of the terminal, so that the network can pause the modification of the RRC connection configuration information of the terminal, and parameter conflict caused by the fact that the terminal receives the RRC connection configuration information in the CPC process is avoided. The method can prevent parameter conflict, and ensure that the cell group has no risk of reconstruction and no risk of interruption of service.

In a third aspect, embodiments of the present application provide another method of wireless communication, the method being executable by a wireless communication device. The method comprises the following steps: transmitting a first RRC connection reconfiguration message carrying synchronization information of the candidate auxiliary main cell and triggering condition information of the condition auxiliary main cell change; receiving a first RRC reconfiguration complete message, wherein the message is used for responding to the first RRC connection reconfiguration message; receiving a CPC execution notification message, wherein the CPC execution notification message is used for learning that a terminal starts to start a CPC flow; a CPC execution response message is sent and used for responding to the CPC execution notification message; receiving a second RRC reconfiguration complete message, wherein the message is used for indicating completion of the CPC flow; during this time, no other RRC connection reconfiguration message is sent, which is used to change the terminal.

In the technical scheme, the network acquires the upcoming switching behavior of the terminal before the terminal starts the CPC flow, and stops sending other RRC connection reconfiguration messages to change the RRC connection configuration information of the terminal. By locking the RRC connection configuration information unchanged, the problem that the terminal fails to store parameters due to improper time for issuing the RRC connection reconfiguration message is avoided, and the cell group is rebuilt.

In a fourth aspect, embodiments of the present application provide another method of wireless communication, the method being executable by a wireless communication device. The method comprises the following steps: receiving a first RRC connection reconfiguration message, wherein the message carries the synchronization information of the candidate auxiliary main cell and the triggering condition information of the condition auxiliary main cell change; transmitting a first RRC reconfiguration complete message, wherein the message is used for responding to the first RRC connection reconfiguration message; in the process of executing CPC, receiving a second RRC connection reconfiguration message from the cell, wherein the second RRC connection reconfiguration message carries cell configuration information; transmitting a second RRC reconfiguration complete message, the message being configured to respond to the second RRC connection reconfiguration message; synchronous access is carried out to the target auxiliary main cell; sending an RRC reconfiguration complete message to the main cell, wherein the message is used for indicating that the configuration of the cell group with successful parameter superposition is completed; an RRC connection reconfiguration message from the primary cell is received, the message indicating operation of a cell group in which parameter superposition failed.

In the technical scheme, the terminal adds a protocol path to enable the RRC reconfiguration complete message to carry a field, wherein the field is used for indicating that the configuration of the cell group with successful parameter superposition is completed. Through the protocol path, the terminal can inform the network that parameter conflict occurs at the terminal, and wait for the participation of the network so as to solve the problem.

In a fifth aspect, embodiments of the present application provide another method of wireless communication, the method being executable by a wireless communication device. The method comprises the following steps: transmitting a first RRC connection reconfiguration message carrying synchronization information of the candidate auxiliary main cell and triggering condition information of the condition auxiliary main cell change; receiving a first RRC reconfiguration complete message, wherein the message is used for responding to the first RRC connection reconfiguration message; in the process of executing CPC by the terminal, a second RRC connection reconfiguration message from the main cell is sent, wherein the second RRC connection reconfiguration message carries cell configuration information; receiving a second RRC reconfiguration complete message, wherein the message is used for responding to the second RRC connection reconfiguration message; after the terminal accesses the target auxiliary main cell, receiving a third RRC reconfiguration complete message, wherein the message is used for indicating that the configuration of the cell group with successful terminal parameter superposition is completed; and sending an RRC connection reconfiguration message, wherein the message is used for indicating the operation of the terminal on the cell group with failed parameter superposition.

In the technical scheme, by adding a protocol path (namely a field carried by the RRC reconfiguration complete message), the protocol path is used for indicating that the configuration of the cell group with successful parameter superposition at the terminal side is completed, so that the network can learn that the terminal has the cell group with the parameter superposition failure. Based on the protocol access, the network can instruct the terminal to release and reconstruct the cells with failed parameter superposition, thereby accelerating the reconstruction speed of the terminal cell group and accelerating the recovery of the service.

In a sixth aspect, an embodiment of the present application provides a wireless communication device, including a processing unit and a transceiver unit, where the processing unit is configured to control the transceiver unit to implement the methods of the first to fifth aspects or any possible implementation method thereof.

In a seventh aspect, embodiments of the present application provide a wireless communication apparatus, which may be a terminal, a base station, or a chip for a terminal or a base station. The apparatus has the function of implementing the method of the first to fifth aspects described above or any of its possible implementation methods. The functions can be realized by hardware, and can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the functions described above.

In an eighth aspect, embodiments of the present application provide a wireless communication device comprising a processor and a memory. Optionally, a transceiver is also included. The memory is for storing a computer program or instructions, and the processor is for calling and running the computer program or instructions from the memory, which when executed by the processor, cause the wireless communication device to perform any implementation of any of the wireless communication methods of the first to fifth aspects described above.

In the alternative, the processor is one or more, and the memory is one or more.

Alternatively, the memory may be integrated with the processor or the memory may be separate from the processor.

Alternatively, the memory may be volatile memory or nonvolatile memory, or may include both volatile and nonvolatile memory.

In a ninth aspect, a system is provided, the system comprising the above wireless communication device and a network equipment.

In a tenth aspect, there is provided a computer program product comprising: a computer program (which may also be referred to as code, or instructions), which when executed, causes a computer to perform the method in any one of the possible implementations of the first to fifth aspects described above, or causes a computer to perform the method in any one of the implementations of the first to fifth aspects described above.

In an eleventh aspect, there is provided a computer readable storage medium storing a computer program (which may also be referred to as code, or instructions) which, when run on a computer, causes the computer to perform the method of any one of the possible implementations of the first to fifth aspects described above, or causes the computer to perform the method of any one of the implementations of the first to fifth aspects described above.

In a twelfth aspect, a system on a chip is provided, which may include a processor. The processor is coupled to the memory and is operable to perform the method of any one of the first to fifth aspects and any one of the possible implementation manners of any one of the first to fifth aspects. Optionally, the system on a chip further comprises a memory. Memory for storing a computer program (which may also be referred to as code, or instructions). A processor for invoking and running a computer program from a memory, causing a device on which the system-on-chip is installed to perform any one of the first to fifth aspects, and a method in any one of the possible implementations of any one of the first to fifth aspects.

In a thirteenth aspect, there is provided a wireless communication device comprising: interface circuitry and processing circuitry. The interface circuit may include an input circuit and an output circuit. The processing circuit is configured to receive a signal via the input circuit and to transmit a signal via the output circuit such that any one of the first to fifth aspects, and the method in any one of the possible implementations of the first to fifth aspects, are implemented.

In a specific implementation process, the wireless communication device may be a chip, the input circuit may be an input pin, the output circuit may be an output pin, and the processing circuit may be a transistor, a gate circuit, a trigger, various logic circuits, and the like. The input signal received by the input circuit may be received and input by, for example and without limitation, a receiver, the output signal may be output by, for example and without limitation, a transmitter and transmitted by a transmitter, and the input circuit and the output circuit may be the same circuit, which functions as the input circuit and the output circuit, respectively, at different times. The embodiments of the present application do not limit the specific implementation manner of the processor and the various circuits.

In one implementation, the wireless communication apparatus may be a wireless communication device, i.e., a computer device supporting wireless communication functionality. Specifically, the wireless communication device may be a terminal such as a smart phone, or may be a radio access network device such as a base station. The system-on-chip may also be referred to as a system-on-chip (SoC), or simply as a SoC chip. The communication chip may include a baseband processing chip and a radio frequency processing chip. The baseband processing chip is sometimes also referred to as a modem (modem) or baseband chip. The radio frequency processing chip is sometimes also referred to as a radio frequency transceiver (transceiver) or radio frequency chip. In a physical implementation, some or all of the communication chips may be integrated inside the SoC chip. For example, the baseband processing chip is integrated in the SoC chip, and the radio frequency processing chip is not integrated with the SoC chip. The interface circuit may be a radio frequency processing chip in the wireless communication device, and the processing circuit may be a baseband processing chip in the wireless communication device.

In yet another implementation, the wireless communication apparatus may be part of a device in a wireless communication device, such as an integrated circuit product, e.g., a system chip or a communication chip. The interface circuit may be an input/output interface, interface circuit, output circuit, input circuit, pin or related circuitry, etc. on the chip or system of chips. A processor may also be embodied as processing or logic circuitry.

Drawings

Fig. 1 is a schematic structural diagram of a wireless communication system according to an embodiment of the present application;

fig. 2 is a schematic diagram of a dual connection scenario provided in an embodiment of the present application;

FIG. 3 is a simplified conditional switch flow diagram provided in an embodiment of the present application;

fig. 4 is a schematic diagram of a secondary node excited condition assisted primary cell change procedure according to an embodiment of the present application;

fig. 5 is a schematic flow chart of a conditional auxiliary primary cell change procedure provided in an embodiment of the present application;

fig. 6 is a schematic flow chart of another conditional auxiliary primary cell change procedure according to an embodiment of the present application;

fig. 7 is a schematic flow chart of another conditional auxiliary primary cell change procedure provided in an embodiment of the present application;

fig. 8 is a schematic flow chart of another conditional auxiliary primary cell change procedure provided in an embodiment of the present application;

Fig. 9 is a schematic flow chart of another conditional auxiliary primary cell change procedure provided in an embodiment of the present application;

fig. 10 is a schematic block diagram of a wireless communication device provided in an embodiment of the present application;

fig. 11 is a schematic structural diagram of a wireless communication device according to an embodiment of the present application.

It should be understood that in the foregoing structural schematic diagrams, the sizes and forms of the respective block diagrams are for reference only and should not constitute an exclusive interpretation of the embodiments of the present application. The relative positions and inclusion relationships between the blocks presented by the structural diagrams are merely illustrative of structural relationships between the blocks, and are not limiting of the physical connection of the embodiments of the present application.

Detailed Description

The technical scheme provided by the application is further described below by referring to the accompanying drawings and examples. It should be understood that the system structures and service scenarios provided in the embodiments of the present application are mainly for explaining some possible implementations of the technical solutions of the present application, and should not be construed as unique limitations of the technical solutions of the present application. Those skilled in the art can appreciate that, as the system evolves and updated service scenarios appear, the technical solutions provided in the present application may still be applicable to the same or similar technical problems.

It should be understood that the technical solution provided in the embodiments of the present application includes an active recovery method for an abnormality after a failure of activation of a security mode and related devices. In the following description of the specific embodiments, some repetition is not described in detail, but it should be understood that the specific embodiments have mutual references and can be combined with each other.

In a wireless communication system, devices may be classified into devices providing wireless network services and devices using wireless network services. Devices providing wireless network services are those devices that make up a wireless communication network, which may be referred to simply as network devices (network equipment), or network elements. Network devices are typically owned by and are responsible for operation or maintenance by operators (e.g., china mobile and Vodafone) or infrastructure providers (e.g., iron tower companies). The network devices may be further divided into radio access network (radio access network, RAN) devices and Core Network (CN) devices. A typical RAN apparatus includes a Base Station (BS).

It should be appreciated that a base station may also sometimes be referred to as a wireless Access Point (AP), or a transmitting receiving point (transmission reception point, TRP). Specifically, the base station may be a general node B (generation Node B, gNB) in a 5G New Radio (NR) system, an evolved node B (evolutional Node B, eNB) of a 4G long term evolution (long term evolution, LTE) system.

Devices that use wireless network services are typically located at the edge of the network and may be referred to simply as terminals (terminals). The terminal can establish connection with the network device and provide specific wireless communication service for the user based on the service of the network device. It should be appreciated that terminals are sometimes referred to as User Equipment (UE), or Subscriber Units (SU), due to their closer relationship to the user. In addition, terminals tend to move with users, sometimes referred to as Mobile Stations (MSs), relative to base stations that are typically placed at fixed locations. In addition, some network devices, such as a Relay Node (RN) or a wireless router, may be considered terminals because they have UE identities or belong to users.

Specifically, the terminal may be a mobile phone (mobile phone), a tablet computer (tablet computer), a laptop computer (laptop computer), a wearable device (such as a smart watch, a smart bracelet, a smart helmet, smart glasses), and other devices with wireless access capability, such as a smart car, various internet of things (internet of thing, IOT) devices, including various smart home devices (such as smart meters and smart home appliances), and smart city devices (such as security or monitoring devices, intelligent road transportation facilities), and the like.

For convenience of description, the base station and the terminal will be taken as examples in this application, and the technical solution of the embodiment of this application will be described in detail.

Fig. 1 is a schematic structural diagram of a wireless communication system according to an embodiment of the present application. As shown in fig. 1, the wireless communication system includes a terminal and a base station. The transmission link from terminal to base station is denoted as Uplink (UL) and the transmission link from base station to terminal is denoted as Downlink (DL) according to the transmission direction. Similarly, data transmission in the uplink may be abbreviated as uplink data transmission or uplink transmission, and data transmission in the downlink may be abbreviated as downlink data transmission or downlink transmission.

In the wireless communication system, the base station can provide communication coverage for a specific geographic area through an integrated or external antenna device. One or more terminals located within the communication coverage area of the base station may access the base station. One base station may manage one or more cells (cells). Each cell has an identification, also called cell identity (cell ID). From the radio resource point of view, one cell is a combination of downlink radio resources and (optionally) uplink radio resources paired therewith.

It should be appreciated that the wireless communication system may conform to the wireless communication standard of 3GPP, or may conform to other wireless communication standards, such as the 802 family (e.g., 802.11, 802.15, or 802.20) of institute of Electrical and electronics Engineers (Institute of Electrical and Electronics Engineers, IEEE). Although only one base station and one terminal are shown in fig. 1, the wireless communication system may include other numbers of terminals and base stations. The wireless communication system may further comprise other network devices, such as core network devices.

The terminals and base stations should be aware of the predefined configuration of the wireless communication system, including the radio access technologies (radio access technology, RAT) supported by the system, as well as the radio resources specified by the system, such as radio frequency bands and carriers. A carrier is a range of frequencies that meets system specifications. This range of frequencies may be determined by the center frequency of the carrier (denoted carrier frequency) and the bandwidth of the carrier. The predefined configuration of these systems may be determined as part of the standard protocols of the wireless communication system or by the interaction between the terminal and the base station. The content of the standard protocols of the wireless communication system may be pre-stored in memories of the terminal and the base station and/or embodied as hardware circuits or software codes of the terminal and the base station.

In the wireless communication system, the terminal and the base station support one or more same RATs, such as 5g nr,4g LTE, or RATs of future evolution systems. Specifically, the terminal and the base station adopt the same air interface parameters, coding scheme, modulation scheme, and the like, and communicate with each other based on radio resources specified by the system. Wherein the air interface parameter is a parameter for describing characteristics of the air interface. In English, the air interface parameter is sometimes also referred to as numerology. The air interface parameters may include subcarrier spacing (subcarrier spacing, SC) and may also include Cyclic Prefix (CP). The wireless communication system may support a variety of different air interface parameters that may be part of a standard protocol.

When different types of base stations are cooperatively networked, because the bandwidth resources and coverage of a single node are limited, wireless resources of a plurality of cells or nodes are concentrated to provide services for the terminal, thereby meeting the higher requirements of users on capacity and coverage. This way of centralizing radio resources of multiple cells or nodes to provide services to users is called multi-connectivity. Multiple connections include carrier aggregation, dual connectivity, and so on.

The dual-connection technology, that is, the terminal may receive signals transmitted by two base stations in one area, and resource transmission is performed through cooperative scheduling between the base stations, so that user performance improvement is facilitated, and certain assistance is provided for overall throughput and switching delay of users.

Today, with the development of technology, mobile communication has undergone multiple generations of development, and is now in the fifth generation (5 g) mobile communication system. In the evolution of the mobile communication network from the fourth Generation (4G) to the fifth Generation, the radio access network and the core network are not synchronously evolved, and thus a 5G radio access network (Next Generation RAN, NG-RAN), a 5G core network (Next Generation Core, NGC), a 4G radio access network (Evolved Universal Terrestrial Radio Access, E-UTRA), and a 4G core network (Evolved Packet Core, EPC) coexist in the system. Since 5G network deployment is a progressive process, this dual connectivity mechanism may exist for a long period of time before the existing 4G network architecture is fully replaced with a 5G network. Such a dual-connectivity network architecture between E-UTRA and NR nodes or between two NR nodes is also known as Multi-mode dual-connectivity (Multi-Radio Dual Connectivity, MR-DC) technology.

Fig. 2 is a schematic diagram of a dual connection scenario provided in an embodiment of the present application, as shown in fig. 2, including a terminal 21, a Master Node 22 (MN), and a Secondary Node 24 (SN). The master node 22 is a radio access node providing a control plane connection for communication between the terminal 21 and the core network, and is connected to a Mobility Management Entity (MME) through a control plane interface S1-MME. Correspondingly, the secondary node 24 is a radio access node which is not connected to the control plane of the core network and which provides only additional resources for the terminal 21.

Each node is associated with a set of serving cells, the primary node 22 corresponding to primary cell group 23 (Master Cell Group, MCG) and the secondary node corresponding to secondary cell group 25 (Secondary Cell Group, SCG). Wherein the MCG23 further comprises a Primary Cell (PCell) and optionally one or more Secondary cells (scells); the SCG25 comprises a secondary primary cell (Primary Secondary Cell, PSCell) and optionally one or more scells. The PCell and PSCell may also be collectively referred to as a Special Cell (SpCell).

The terminal 21 is configured such that the resources it uses are provided by two nodes 22, 24 of a non-ideal backhaul connection, one of which provides NR access and the other of which provides E-UTRA or NR access. In addition, since the core network is also distinguished from EPC by NGC, multimode dual connectivity can be mainly divided into the following four types:

1. evolved universal terrestrial radio access and dual connectivity mode for new air interface (E-UTRA-NR dual connectivity, EN-DC). In this mode, the primary node 22 to which the terminal 21 is connected is an eNB, and the secondary node 24 is an en-gcb. The master node 22 is connected to the core network EPC via an S1 interface and to the slave node 24 via an X2 interface. The secondary node 24 may connect with the EPC through an S1-U interface and with other en-gNB through an X2-U interface.

2. NR-E-UTRA double linkage (NE-DC). In this mode, the primary node 22 to which the terminal 21 is connected is a gNB and the secondary node 24 is a ng-eNB. The primary node 22 is connected to the core network NGC and may be connected to the secondary node 24 via an Xn interface.

3. NG-RAN E-UTRA-NR dual connectivity (NGEN-DC). In this mode, the primary node 22 to which the terminal 21 is connected is a ng-eNB, and the secondary node 24 is a gNB. The primary node 22 is connected to the core network NGC and may also be connected to the secondary node 24 via an Xn interface.

4. NR-NR double connectivity (NR-DC). In this mode, the primary node 22 to which the terminal 21 is connected is one gNB, and the secondary node 24 is also one gNB. The primary node 22 is connected to the core network NGC via an NG interface and to the secondary node 24 via an Xn interface.

The following description and the subsequent embodiments are developed in the main scenario of the EN-DC mode, where in the mode, the master node is a 4G base station eNB, and may download a control plane message and a user plane message to the terminal, and the auxiliary node is a 5G base station gNB, and may send, as an additional radio bearer resource, a message to the terminal under the direction of the master node, where the message includes the control plane message and the user plane message, and the message is both from the master node.

It should be appreciated that the following embodiment method can be extended to other MR-DC modes as well to solve the same technical problems.

In EN-DC, the UE connects two cell groups, MCG and SCG, respectively, each of which in turn has one primary cell group (corresponding to the primary node eNB) and possibly a plurality of secondary cell groups (corresponding to the secondary node gNB). Since the cell group can be divided into a primary cell and a secondary cell, the cells to which the UE is connected can be divided into the following three types: one primary cell PCell in the MCG, one primary secondary cell PSCell in the SCG, and one or more secondary cells scells belonging to groups, if any.

When a terminal is moving, it enters the coverage of one cell from the coverage of another cell, and thus a handover is required. In 5G, to enhance terminal mobility, a conditional handover (Conditional Handover, CHO) technique is introduced.

The conditional handover is that the network configures handover conditions for the terminal side, the use of the conditional handover is determined by the network, the terminal side evaluates when the handover conditions are valid, and can support the conditional handover configuration of one or more candidate cells. The CHO configuration includes CHO candidate cell configuration generated by the candidate target node and execution conditions generated by the source node and is issued to the terminal via the source node RRC connection reconfiguration message.

The conditional switching flow comprises three stages of switching preparation, switching execution and switching completion. When the UE enters the cell boundary area, the UE reports based on the configuration measurement of the source node, and the source node decides whether to configure CHO for use after receiving the report of the UE. And under the condition that the source node decides to use CHO, sending a switching request to the candidate target node, and after receiving a condition request confirmation, sending a first RRC connection reconfiguration message to the UE, wherein the first RRC connection reconfiguration message carries the synchronization information of the candidate target cell and the triggering condition of the condition auxiliary main cell change. The UE starts evaluating the execution conditions upon receiving the conditional handover configuration, and when it satisfies one or more CHO execution conditions, the UE is handed over to the target cell. And then the target cell node informs the source node that the UE is successfully switched, and the source node sends a conditional switching cancellation message to other candidate target nodes for canceling the conditional switching preparation of the other candidate target nodes.

Fig. 3 is a simplified CHO flow chart provided in the embodiment of the present application, where UE represents a terminal device, NW represents a network, and the network includes a primary node and a secondary node, or may refer to a cell and a cell group corresponding to the nodes, which are collectively referred to as a network. The CHO flow chart comprises the following steps:

step 301, after the network configures the UE measurement procedure, the UE reports according to the measured configuration and the result.

In step 302, CHO is used for network decision, and CHO may be reported based on measurement or determined based on gNB.

Step 303, the network performs CHO handover preparation, mainly comprising selecting candidate cells and allocating resources for the UE.

Step 304, the network sends an RRC connection reconfiguration message to the UE, where the RRC connection reconfiguration message includes CHO candidate cell configuration and CHO execution conditions. The CHO execution conditions may consist of one or two trigger conditions.

Step 305, the UE sends an RRC reconfiguration complete message to the source gNB, where the RRC reconfiguration complete message is used to indicate successful reception and application of the RRC connection reconfiguration message in step 304.

Step 306, after receiving the CHO configuration, the UE starts to evaluate CHO execution conditions of the candidate cells.

Step 307, the UE selects the target cell according to the CHO evaluation condition and accesses the target cell. Wherein the target cell is one of the candidate cells.

Step 308, after the UE completes synchronization with the candidate cell, an RRC reconfiguration complete message is sent to the network, where the RRC reconfiguration complete message is used to inform the network that the UE completes CHO procedure.

Step 309, updating relevant information by the network, and completing the CHO handover.

Steps 301 to 305 correspond to a handover preparation phase of the CHO flow, steps 306 and 307 correspond to a handover execution phase, and steps 308 and 309 correspond to a handover completion phase.

In step 303, CHO handover preparation by the network mainly sends a handover request to one or more cells under one or more candidate nodes for the source node, these cells being candidate cells afterwards. The source node sends a CHO request message to each candidate cell.

After the candidate cell receives the CHO request message, an admission control process is performed to allocate resources for the UE. After the candidate cell completes the resource allocation operation, a CHO handover request response message is sent to the source node, where the CHO handover request response message carries configuration information of the CHO candidate cell. Since the CHO handover request response message is a candidate node to which the candidate cell belongs, it should be noted that each candidate node needs to send a CHO handover request response message for each candidate cell.

In step 305, after receiving the RRC connection reconfiguration message in step 304, the UE maintains connection with the network (mainly the source node for CHO handover), and if a download message from the network can be received, the UE starts evaluating CHO execution conditions of candidate cells. Thus, in the CHO handover execution phase, the UE may accept messages from the network regarding RRC connection configuration.

In step 307, the UE selects a target cell from the candidate cells according to CHO execution conditions, and synchronously accesses the target cell. The synchronous access is a random access flow.

In step 308, after sending the RRC reconfiguration complete message, the UE ends the CHO procedure at the UE. The UE may release the stored CHO configuration.

In step 309, the network performs CHO information update, including sending a handover success message from the target node to the source node, informing the target node of the connection status information of the UE, and sending CHO handover cancel messages to other candidate nodes, etc. That is, the network needs to update the connection status information of the UE from the source node to the target node, so that the core network can switch the path of the downlink data to the target node. In addition, the network also needs to cancel CHO resources reserved for the UE by other candidate nodes, and release information of the UE reserved by the source node, such as a context of the UE.

Based on the above flow, the UE can implement conditional handover to the primary cell, the primary and secondary cells, and the secondary cell, and enhance mobility. When the handover target is a primary and secondary cell, the flow of conditional handover may also be referred to as a conditional primary and secondary cell node change (Conditional PSCell Change, CPC) flow. Since the primary and secondary cells correspond to the secondary node, the CPC procedure may also be considered as a change of configuration of the secondary node by the UE.

In the CPC process, a main node or an auxiliary node in the network can configure a change condition for the UE side, and when the UE measures that the CPC change condition is met, the UE and the target auxiliary node are synchronously accessed, then the source auxiliary node is released, and the change of the auxiliary node is completed. The configuration of the CPC change condition may be triggered by the primary node or the secondary node for transmitting the UE context and secondary cell group configuration from the source secondary node to the target secondary node.

It should be noted that, an RRC connection reconfiguration message carrying information of the configuration and candidate cell group of the CPC change condition may be sent by the master node, and this message is carried by SRB 1; in addition, the message may also be sent by the secondary node, where the message is carried by SRB 3. After receiving the RRC connection reconfiguration message, the UE may identify the sender through the SRB bearer and send an RRC reconfiguration complete message to the corresponding node, so as to respond to the RRC connection reconfiguration message. In the following embodiments, only the RRC connection reconfiguration message sent by the primary node and its corresponding primary cell is taken as an example, but it should be understood that embodiments may also be extended to be sent by the secondary node and its corresponding secondary primary cell.

Fig. 4 is a schematic CPC flow chart excited by an auxiliary node provided in the embodiment of the present application, where a main body participating in the flow chart is divided into a UE and each cell, where from the perspective of an execution object of signaling interaction, the cell may be understood as a base station, and from the perspective of a network, the cell may also be considered as a corresponding primary node or auxiliary node; here, for ease of understanding, cells are referred to. The CPC flow comprises the following steps:

step 401, the UE reports the measurement data to the source PSCell.

In step 402, the source PSCell decides to initiate a CPC procedure, and the initiation of CPC may be based on measurement data or PSCell decision.

In step 403, the source PSCell sends a change requirement to the PCell, notifying the PCell candidate target PSCell and optional CPC conditions.

Step 404, the PCell sends an addition request requesting the candidate PSCell to allocate resources for the UE. The addition request sent by the PCell includes measurement data related to candidate pscells.

Step 405, after the candidate PSCell receives the addition request of the PCell, a request response message is added to the PCell.

Step 406, the PCell sends an RRC reconfiguration message to the UE, including trigger conditions of the CPC and synchronization information of the candidate PSCell.

Step 407, the UE sends an RRC reconfiguration complete message to the PCell, where the RRC reconfiguration complete message is used to indicate successful reception and application of the RRC reconfiguration message in step 406.

In step 408, the PCell sends an acknowledgement message to the source PSCell, to inform the source PSCell that the addition request procedure is successful or failed.

Step 409, the PCell sends a reconfiguration complete message to the candidate PSCell, for indicating success of the RRC connection reconfiguration message sent to the UE in step 406.

Step 4010, synchronizing to the target PSCell through random access when the UE evaluates that the CPC condition is met.

Step 4011, after completing the random access, the UE sends an RRC reconfiguration complete message to the PCell, where the RRC reconfiguration complete message is used to indicate completion of the CPC procedure.

In step 4012, the target PSCell sends a primary and secondary cell handover success message to the PCell, informing the PCell that the UE has successfully accessed the target PSCell.

Step 4013, the PCell sends an auxiliary node release request to the source PSCell and the candidate PSCell, where the auxiliary node release request is used to release resources allocated to the UE by the candidate PSCell and the source PSCell, and the source PSCell and the candidate PSCell release the prepared resources after receiving them.

Step 4014, the source PSCell and the candidate PSCell send a release request acknowledgement message to the PCell for acknowledging receipt of the release request in the previous step and completion of the release of the resource.

Wherein steps 401 to 409 correspond to a handover preparation phase of CHO procedure, step 4010 corresponds to a handover execution phase, and steps 4011 to 4014 correspond to a handover completion phase.

As can be seen from the above procedure, after receiving the RRC connection reconfiguration message from the PCell, the UE carries synchronization information of the candidate target cell and trigger conditions of the CPC. And the UE updates the information and the configuration, the result to be measured meets the related trigger condition, and the condition switching process is started automatically.

After the UE starts the CPC flow, the UE applies the related configuration of the target PSCell, updates the synchronization information of the target PSCell, completes synchronization with the target PSCell through the random access flow, and then sends an RRC reconfiguration completion message to the network for indicating completion of the CPC flow.

It should be noted that, after the PCell receives the RRC reconfiguration complete message until it receives the second RRC reconfiguration complete message, it cannot know whether the UE has initiated the CPC procedure. That is, the PCell is informed of the CPC handover result of the UE by the UE and the target PSCell after the CPC procedure is completed. In this process, the network may issue a new RRC connection reconfiguration message to the UE through the PCell, which may carry RRC configuration information of any cell (e.g., source PSCell) connected by multiple UEs, or RRC connection configuration information of a designated target PSCell. The method comprises the steps of configuring a source PSCell, and indicating UE to access a designated target PSCell. This period of time is referred to as the collision period in fig. 4.

Thus, the UE may receive a new RRC connection reconfiguration message during the collision period, and in the prior art, the UE may respond back to the operation of the message until the CPC procedure is completed. Then, the UE will apply the RRC connection configuration information carried by the new RRC connection reconfiguration message. Since this new RRC connection reconfiguration message carries RRC connection configuration information of the source PSCell or RRC connection configuration information of the target PSCell specified by the PCell, it is understood that these configuration information are most likely not matched with the RRC configuration information of the cell after the UE completes CPC. The UE superimposes these configuration information on the existing configuration when applying it. This stacking operation is not reasonable and does not necessarily succeed. If the superposition is not successful, the UE fails to store parameters, the MCG reconstruction is triggered according to the protocol, and the continuity of the service is affected; and even if the superposition is successful, the superimposed parameters are highly likely to be erroneous.

In addition, the UE may discard the new RRC connection reconfiguration message, and not apply the RRC connection configuration information about the cell carried by the new RRC connection reconfiguration message. But since the UE must send an RRC reconfiguration complete message to the network after receiving the RRC connection reconfiguration message. If the UE does not apply RRC connection configuration information, this will result in the network receiving an incorrect RRC reconfiguration complete message. In this case, the network may require the UE to reestablish the RRC connection, affecting traffic continuity, and even releasing the UE context, resulting in traffic interruption.

That is, in the prior art, the PCell cannot learn the start of UE handover PSCell in time, and may issue new RRC connection configuration information to the UE at any time, where the RRC connection configuration information may be any cell connected to a plurality of UEs, or may be a target secondary primary cell for UE-specific handover. The UE must wait for the CPC procedure to finish to inform the network that the secondary primary cell is changed, and may receive a new RRC connection configuration from the network during the collision period and must respond to the new configuration.

In order to solve the above problems, the general idea of the embodiment of the present application is as follows: under the condition that a new RRC connection reconfiguration message is received, the UE can autonomously interrupt the CPC flow and preferentially apply the configuration information of the target PScell carried by the RRC connection reconfiguration message, so that the situation that the configuration information issued by the network conflicts with the configuration information autonomously switched at the UE side is avoided, and the service experience is optimized. The following embodiments are compatible with existing standard protocols and are implemented as products.

Fig. 5 is a schematic diagram of a conditional PSCell change procedure according to an embodiment of the present application. In this procedure, the UE starts with receiving a first RRC connection reconfiguration message from the network, where the first RRC connection reconfiguration message carries synchronization information of the candidate target cell and a triggering condition of the conditional auxiliary primary cell change, so that when the triggering condition is activated, the conditional auxiliary primary cell change is started. The flow chart comprises the following steps:

step 501, receiving an RRC connection reconfiguration message from the network, where the RRC connection reconfiguration message carries synchronization information of the candidate target cell and a triggering condition of the condition-assisted primary cell change.

Step 502, sending an RRC reconfiguration complete message to the network, where the RRC reconfiguration complete message is used to respond to the RRC connection reconfiguration message in step 501.

In step 503, if the evaluation CPC condition is satisfied, a CPC procedure is started.

Step 504, in the CPC procedure, a new RRC connection reconfiguration message from the network is received, where the new RRC connection reconfiguration message carries node configuration information.

Step 505, sending an RRC reconfiguration complete message to the PCell, where the RRC reconfiguration complete message is used to respond to the RRC connection reconfiguration message in step 504.

Step 506, according to the target auxiliary primary cell information carried in the RRC connection reconfiguration message in step 504, an uplink message is sent, where the uplink message is used to indicate whether the target auxiliary primary cell handover is successful or not.

After judging that the condition switching can be carried out, the network transmits an RRC connection reconfiguration message to the UE. And the UE receives the synchronous information of the candidate target auxiliary main cells and the triggering condition of CPC carried by the message, selects the target auxiliary main cells under the condition that the triggering condition is met, and autonomously starts CPC flow for attempting synchronous access to the target auxiliary main cells.

However, before the UE completes the CPC procedure, the network cannot inform the network that the conditional handover procedure is started, so that the network can issue a new RRC connection reconfiguration message for updating the RRC connection configuration at the UE side without knowing that the UE starts the CPC.

The CPC procedure, i.e. the aforementioned collision period, includes the following two cases:

1. and when the UE executes CPC, before the RRC reconfiguration complete message is sent, the RRC reconfiguration complete message is used for indicating the completion of CPC flow. In this case, the included period of time is: and the UE evaluates the CPC condition, and before the UE completes the random access to the PScell and sends a third RRC reconfiguration completion message in the random access process of the UE to the target PScell meeting the CPC condition. In this stage of CPC procedure execution, the UE may rollback the RRC connection parameters modified due to CPC according to its historical operation, so that it rolls back to before CPC start. In this case, the UE suspends the CPC procedure and returns the RRC connection parameters so that it may superimpose the information carried by the received RRC connection reconfiguration message. When the information is related to any cell (such as a source PSCell) connected by the UE, MCG reconstruction caused by parameter superposition failure can be avoided. And when the synchronization information for the designated target PSCell is carried in the RRC connection reconfiguration message, the UE superimposes the RRC connection configuration information and accesses the designated target PSCell instead of the target PSCell determined by the CPC procedure.

2. And in a first time period after the UE completes the CPC process and sends the RRC reconfiguration complete message, wherein the first time period is smaller than the time consumption of the primary cell for receiving the RRC reconfiguration complete message and issuing new RRC configuration, and the RRC reconfiguration complete message is used for indicating the completion of the CPC process. At this stage, the UE has completed updating the RRC connection configuration and thus cannot perform parameter backoff. In this case, the UE superimposes the RRC connection configuration information carried by the RRC reconfiguration complete message, and stops accessing the target PSCell indicated by the CPC procedure.

As described above, the RRC connection reconfiguration message may be used to update the RRC connection configuration of the UE with any cell connected, including but not limited to configuration of measurements, channel state information configuration, and the like. The above configurations are all overlapped based on the original configuration condition which is not changed by the CPC procedure, so that the configuration conflicts with the new configuration of the target cell after the UE starts the conditional handover. In addition, the RRC connection reconfiguration message may also carry configuration information of a target secondary primary cell specified by the network, so as to instruct the UE to change to and access synchronously with the specified target secondary primary cell.

And when the UE terminates the CPC flow, receiving the RRC connection reconfiguration message, and sending a corresponding RRC reconfiguration completion message after applying the RRC connection configuration information carried by the UE. Then, the UE can confirm whether the parameter superposition is successful or not according to the content of the RRC connection reconfiguration message, and inform the network:

1. When the RRC connection reconfiguration message carries synchronization information related to a target PSCell for indicating handover of the UE, an uplink message sent by the UE to the target PSCell is used for synchronous access, i.e. a random access preamble message.

2. When the information carried by the RRC connection reconfiguration message does not include the synchronization information related to the target PSCell, that is, the information carried by the message is used to modify RRC connection configuration information related to any cell (e.g., source PSCell) connected to the UE, the UE sends an SCG failure information message to the PCell, where the SCG failure information message is used to inform the network that the UE experiences an SCG failure and needs to be rebuilt.

In the above case, before the CPC procedure is completed, the UE receives the RRC connection reconfiguration message, and applies its configuration in time, so as to prevent transmission errors of the corresponding RRC reconfiguration completion message caused by not adopting or erroneously overlaying the RRC connection configuration information carried by the RRC connection reconfiguration message, where the transmission errors include content missing due to not adopting the foregoing configuration information, and further cause network release resources and MCG cell reestablishment.

As described above, in order to distinguish whether the RRC connection reconfiguration message carries synchronization information related to the target PSCell, it is necessary to determine fields therein. In the RRC connection reconfiguration message, since it is a modification of the RRC connection configuration between the UE and the cell, it will contain indicative information of the cell, which is carried by the cell group ID (cellGroupId) field for indication as either a primary cell group or a secondary cell group.

Under this field there is in turn a special cell configuration (spCellconfig) field, which is an optional field, the special cells including PCell and PSCell. For the configuration of PSCell, it can be seen that this field has the following structure:

wherein, the servCellIndex field is used to indicate the serving cell ID of the target PScell. This field is an optional field that only exists when the RRC connection reconfiguration message is for a secondary cell group. Specifically, when the received RRC configuration message is a reconfiguration of the PSCell, the message must include a field servCellIndex field; when the message carries reconfiguration information for the PCell, the field is not included. Therefore, it can be determined whether the RRC connection reconfiguration message is a parameter modification for PCell or PSCell by checking whether the received RRC connection reconfiguration message includes a field servCellIndex field. If not, the RRC connection reconfiguration to the PCell, otherwise to the PSCell.

Since the reconfiguration of the RRC connection does not only include access to the new cell in case of handover, it needs to be implemented through the subsequent reconfigurationwisync field in order to distinguish this case. This field is used to indicate the parameters of the UE to target spCell sync reconfiguration. This field is mandatory in the case of spCell change, PSCell addition, PSCell SI update and security key change. The reconfigurationWithSync field carries specific configuration of cell specific parameters, random access channels and the like of the target spCell, and after the UE applies relevant configuration, the UE can initiate a random access procedure for the target spCell. It is noted that when MCG handover is performed, the existing SCG is released according to the protocol requirement, and at this time, the new random access can be performed by carrying the configuration of the existing SCG through the field, so as to keep the configuration of the SCG unchanged.

Therefore, in the embodiment of the present application, it is selected to check whether the received RRC connection reconfiguration message includes the reconfigurationWithSync field in the case that the cellGroupId field indicates a secondary cell group, so as to determine that the RRC connection reconfiguration message is a parameter modification for the source secondary primary cell or a new target secondary primary cell. If the reconfigurationWithSync field is not included, the method is to assist the primary cell to the source; otherwise, the connection of the target auxiliary main cell is reconfigured, and the UE needs to execute random access.

Fig. 6 is a schematic diagram of a conditional PSCell change flow provided in an embodiment of the present application, where after a CPC flow is started, a UE receives an RRC connection reconfiguration message before sending an RRC reconfiguration complete message for indicating that the CPC flow is completed. The flow chart comprises the following steps:

step 601, receiving an RRC connection reconfiguration message from the PCell, where the RRC connection reconfiguration message carries synchronization information of a candidate target cell and a triggering condition of a condition-assisted primary cell change.

Step 602, sending an RRC reconfiguration complete message to the PCell, where the RRC reconfiguration complete message is used to respond to the RRC connection reconfiguration message in step 601.

Step 603, if the evaluation CPC condition is satisfied, starting the CPC procedure.

Step 604, receiving an RRC connection reconfiguration message from the PCell, where the RRC connection reconfiguration message carries configuration information of a cell.

Step 605, the CPC configuration is revoked, and the RRC connection configuration is returned to the state before the CPC procedure is started.

Step 606, sending an RRC reconfiguration complete message to the PCell, where the RRC reconfiguration complete message is used to respond to the RRC connection reconfiguration message in step 604.

Step 607, according to the information of the cell configuration carried in the RRC connection reconfiguration message in step 604, performing random access to the target PSCell when the message carries synchronization information of the target PSCell.

Steps 601 to 604 may refer to steps 501 to 504, and are not described herein.

In this procedure, the UE receives an RRC connection reconfiguration message before evaluating the target PSCell for CPC condition satisfaction. At this time, the RRC connection configuration information carried by the message is inconsistent with the UE itself and the configuration information changed after CPC evaluation, and the parameter stacking is unsuccessful, which may cause a conflict, resulting in unsuccessful parameter saving.

In step 605, after receiving the RRC connection reconfiguration message, the UE cancels the RRC connection configuration information update performed after the CPC condition evaluation is satisfied. The UE refers to the operation history record of the UE in the CPC executing process, withdraws the operation (including changing and releasing) of the related parameters, and restores the parameters to the state before the CPC process is started, namely, the parameters are changed from the configuration content of the target auxiliary main cell appointed by the CPC to the state before the target auxiliary main cell appointed by the CPC. And then, the UE terminates the CPC flow, releases relevant CPC resources, and does not access the candidate auxiliary primary cells selected after CPC evaluation. The UE does not inform the PCell about this failure of the CPC procedure execution.

Thereafter, as shown in step 606, the UE applies all the RRC connection configuration information carried by the UE according to the RRC connection reconfiguration message in step 604, and sends an RRC reconfiguration complete message after the application is completed, so as to prevent the PCell from abnormal operations, such as releasing the UE context, caused by the failure to receive the RRC reconfiguration complete message.

In step 607, the UE determines whether the RRC connection reconfiguration message in step 604 carries information about the cell configuration, i.e., whether the configuration information for accessing the target cell for which handover is specified by the PCell is carried. According to the above description, the UE may perform the determination by determining whether the reconfigurationwisync exists in the case of the secondary cell group (through the cellGroupId field).

Only if the two fields exist at the same time, the UE is configured to access the target PSCell designated for handover, and the UE may initiate a random access procedure to the target PSCell, including sending a random access preamble message to the target PSCell, and may indicate initiation of a handover procedure.

If the two fields do not exist at the same time, the UE needs to initiate an SCG failure procedure, and sends an SCG failure message to the PCell, where the message is used to inform the network that the UE experiences an SCG failure, and hopes that the network indicates to re-establish the SCG. That is, the UE informs the network of the failed handover result of the UE by transmitting an SCG failure message.

According to the scheme, under the condition that the UE receives the RRC connection reconfiguration message in the CPC process and causes the parameter configuration to be opposite, the operation is cancelled after the CPC is started, so that the UE responds to the second RRC connection reconfiguration message and configures the parameter information carried by the second RRC connection reconfiguration message. This avoids the UE context release that may be caused by not responding to the RRC connection reconfiguration message, and the UE save failure caused by directly superimposing the parameters carried by the message without changing the parameters back to the original RRC connection, which further brings about service interruption and MCG reestablishment.

In addition, by judging the reconfiguration object of the RRC connection reconfiguration message, the UE sends different uplink messages to the network, so that when the RRC connection reconfiguration message does not indicate the target PScell for switching, the SCG failure flow is actively triggered to avoid MCG reconstruction caused by parameter superposition failure.

Therefore, by using the method, whether the RRC connection reconfiguration message received by the UE in the CPC process carries the synchronization information of the target PScell indicating the switching or not can be applied, the RRC connection configuration information carried by the message can be applied, and a correct RRC reconfiguration completion message can be sent to the network, so that the reestablishment of the cell group and the service interruption are avoided.

Fig. 7 is a schematic diagram of another CPC flow provided in an embodiment of the present application, where after a CPC flow is started, a UE receives an RRC connection reconfiguration message before sending an RRC reconfiguration complete message for indicating that the CPC flow is completed. The flow chart comprises the following steps:

Step 701, receiving an RRC connection reconfiguration message from the PCell, where the RRC connection reconfiguration message carries synchronization information of the candidate target cell and a trigger condition of the CPC.

Step 702, sending an RRC reconfiguration complete message to the PCell, where the RRC reconfiguration complete message is used to respond to the RRC connection reconfiguration message in step 701.

In step 703, if the evaluation CPC condition is satisfied, a CPC flow is started.

Step 704, sending an RRC connection reconfiguration message to the PCell, where the RRC connection reconfiguration message is used to indicate that the CPC procedure is completed.

Step 705, receiving an RRC connection reconfiguration message from the PCell, where the RRC connection reconfiguration message carries cell configuration information.

Step 706, sending an RRC reconfiguration complete message to the PCell, where the RRC reconfiguration complete message is used to respond to the RRC connection reconfiguration message in step 705.

Step 707, according to the target PSCell information carried in the RRC connection reconfiguration message in step 705, if the message does not carry synchronization information of the target PSCell, sending a secondary cell group failure information message to the PCell, where the secondary cell group failure information message is used to indicate a failure of handover of the target PSCell.

The steps 701 to 703 may refer to the steps 501 to 503, and are not described herein.

After completing access to the target PSCell that meets the CPC condition evaluation, the UE sends an RRC reconfiguration complete message to the PCell, as shown in step 704, to indicate that the CPC procedure is completed. The UE receives an RRC connection reconfiguration message from the PCell in a first time period after the UE has sent the message, where the first time period is less than the total time period for the PCell to send an RRC configuration message after receiving the RRC reconfiguration complete message, as shown in step 705. That is, when the UE has completed the CPC procedure and completed uplink synchronization with the CPC-specified target PSCell, the UE receives an RRC connection reconfiguration message from the PCell. The cells indicated by the two are inconsistent, so that parameter hedging is caused. The specific value of the first duration may be an empirical value of the base station performing the above operation, and may range from 30 to 50 milliseconds.

In this case, since the UE transmits the RRC reconfiguration complete message indicating completion of the CPC procedure, the CPC procedure is completed for the UE, and the RRC connection configuration change due to the procedure cannot be revoked. Based on this, the UE must superimpose the RRC connection configuration content carried by the received RRC connection reconfiguration message onto the changed relevant parameters, and then send an RRC reconfiguration complete message for responding to the RRC connection reconfiguration message as shown in step 706.

In step 707, the UE determines whether the RRC connection reconfiguration message carries information about the cell configuration, that is, whether the UE carries configuration information for accessing the target cell for handover specified by the PCell. According to the above description, the UE may perform the determination by determining whether the reconfigurationwisync exists in the case of the secondary cell group (through the cellGroupId field).

The two fields do not exist at the same time, the UE needs to initiate an SCG failure flow, and send an SCG failure message to the PCell, where the message is used to inform the network that the UE experiences an SCG failure, and hope that the network indicates to re-establish the SCG. That is, the UE informs the network of the failed handover result of the UE by transmitting an SCG failure message.

According to the scheme, under the condition that the configuration of the target PScell is not specified by the received RRC connection reconfiguration message, the parameter modification cannot be withdrawn, and the RRC connection configuration should not be overlapped, the UE actively triggers the secondary cell group failure flow, and uses the reconstruction of the SCG to avoid the reconstruction of the MCG caused by the parameter overlapping failure, so that the network participates in the reconstruction of the SCG, thereby reducing the time delay of service recovery.

Besides the method compatible with the existing standard protocol, the problem of parameter hedging can be solved by improving the existing protocol.

As shown in fig. 8, another CPC flow chart provided in an embodiment of the present application includes the following steps:

step 801, an RRC connection reconfiguration message from the PCell is received, where the RRC connection reconfiguration message carries synchronization information of the candidate target cell and a triggering condition of the condition-assisted primary cell change.

Step 802, sending an RRC reconfiguration complete message to the PCell, where the RRC reconfiguration complete message is used to respond to the RRC connection reconfiguration message in step 601.

Step 803, under the condition that the CPC condition is evaluated to be met, starting a CPC flow.

Step 804, a CPC execution notification message is sent to the PCell, for indicating the start of the CPC procedure.

Step 805, receiving a CPC execution response message from the PCell, where the CPC execution response message is used to indicate that the CPC execution notification message is successfully received.

Step 806, after completing the CPC procedure, an RRC reconfiguration complete message is sent to the PCell, to indicate completion of the CPC procedure.

After step 805, after receiving the CPC execution response message, the UE starts executing the CPC procedure, and modifies the relevant configuration information. Meanwhile, the master node corresponding to the PCell keeps the configuration of the UE unchanged, and delays processing a message from the core network or the auxiliary node, which requires the UE to change RRC connection configuration information. Wherein the master node maintains the configuration of the UE until receiving the RRC reconfiguration complete message in step 806. That is, the network does not make any change to the RRC connection configuration of the UE in the process that the UE performs the CPC procedure. If the network needs to reconfigure the RRC connection to the UE, the UE waits to be informed of the end of the CPC flow through the RRC reconfiguration completion message, and then sends the RRC connection reconfiguration message to the UE, so that parameter undershoot caused by sending the message in the CPC process is avoided.

Therefore, before the CPC process is started, the UE adds a handshake process with the network (namely, informs the network of starting the CPC process and waits for the response of the network), thereby avoiding the network from sending RRC connection reconfiguration information in the CPC process and solving the problem of parameter hedging.

In addition to the above-mentioned solution to adding a new signaling message without interrupting the UE performing CPC procedure, the problem of parameter undershoot can be solved by adding a protocol path.

As shown in fig. 9, another CPC flow chart provided in an embodiment of the present application includes the following steps:

step 901, receiving an RRC connection reconfiguration message from the PCell, where the RRC connection reconfiguration message carries synchronization information of the candidate target cell and a trigger condition of the CPC.

Step 902, sending an RRC reconfiguration complete message to the PCell, where the RRC reconfiguration complete message is used to respond to the RRC connection reconfiguration message in step 701.

In step 903, if the evaluation CPC condition is satisfied, a CPC procedure is started.

Step 904, receiving an RRC connection reconfiguration message from the PCell, where the RRC connection reconfiguration message carries configuration information of a cell.

Step 905, sending an RRC reconfiguration complete message to the PCell, where the RRC reconfiguration complete message is used to indicate that the CPC procedure ends.

Step 906, sending an RRC reconfiguration complete message to the target PSCell, where the RRC reconfiguration complete message is used to indicate that the CPC procedure ends.

Step 907, performing random access to the target PSCell.

Step 908, sending an RRC reconfiguration complete message to the PCell, where the RRC reconfiguration complete message is used to indicate a cell group with successful parameter stacking, and the parameter is carried by the RRC connection reconfiguration message in step 904.

Step 909, receiving an RRC connection reconfiguration message from the PCell, where information carried by the RRC connection reconfiguration message is used to indicate an operation of a cell group with failed parameter superposition.

As described above, in step 904, the RRC connection reconfiguration message received by the UE, the cell configuration information that can be carried by the message includes configuration information for the cells of the primary cell group and configuration information for the cells of the secondary cell group. Since the UE performs CPC procedure, the modified RRC connection configuration information mainly relates to pscells in the secondary cell group. When the message contains only configuration information of cells of the primary cell group, however, the behavior of parameter superposition occurs on parameters related to the primary cell group with a lower probability of being affected. When the message contains configuration information of the cells of the secondary cell group, the behavior of parameter superposition occurs on parameters related to the secondary cell group, and the parameters are highly likely to be changed due to CPC flow, so that parameter superposition failure occurs, resulting in interruption of service.

For the RRC connection reconfiguration message, the UE completes the CPC procedure first, that is, completes synchronous access to the target PSCell selected by the CPC procedure (steps 905 to 907). And then, the UE performs parameter superposition according to the cell configuration information carried by the RRC connection reconfiguration message.

When the RRC connection reconfiguration message carries configuration information of a cell of the secondary cell group, in step 908, a protocol path is added to an RRC reconfiguration complete message sent to the PCell by the UE, so as to notify the PCell that the UE only takes effect of the configuration information of a cell of the primary cell group carried by the RRC connection reconfiguration message in step 904, and a specific implementation manner may consider that a corresponding indication field is added to the RRC reconfiguration complete message through 4G.

Through the indication field, the PCell and the corresponding master node can learn that the UE takes effect of the configuration information of the cells of the master cell group and the configuration information of the cells of the auxiliary cell group fails to take effect. Thus, the PCell issues a new RRC connection reconfiguration message to instruct the UE to handle the configuration of the secondary cell group's cells, e.g., to release the existing secondary cell group resources and to establish a new secondary cell group at the same time, or to reconfigure the primary and secondary cell groups as a whole. The former implementation mode can be realized through a ReleaseAndAdd field which is carried by the RRC connection reconfiguration message and aims at the secondary cell group, and the latter implementation mode can be realized through a FullConfig field which is carried by the message.

Therefore, the UE can inform the PCell (namely the corresponding master node and the network) that the UE generates parameter hedging through a new protocol path, so that the reconstruction of a cell group caused by the failure of parameter superposition is avoided through the intervention of the network, and the continuity of the service is enhanced.

The following describes a wireless communication device provided in an embodiment of the present application.

Referring to fig. 10, which is a schematic block diagram of a wireless communication device according to an embodiment of the present application, the communication device 1000 includes a processing unit 1010 and a transceiver unit 1020, which are connected by a line. The wireless communication device is used for realizing the steps of the corresponding terminal in the above embodiments:

the processing unit 1010 is configured to control the transceiver unit 1020 to perform communication with a network; and the control transceiver unit is used for starting a random access flow when the service requirement is perceived, so that RRC connection is established with the network.

The transceiver 1020 is configured to receive the first RRC connection reconfiguration message, send a first RRC reconfiguration complete message, receive a second RRC connection reconfiguration message from the primary cell, and send the second RRC reconfiguration complete message to the primary cell.

In a possible implementation method, the transceiver unit 1020 is further configured to initiate a random access procedure to the target secondary primary cell when the cell configuration information carried by the second RRC connection reconfiguration message includes synchronization information of the target PSCell.

In a possible implementation method, the transceiver unit 1020 is further configured to send a secondary cell group failure information message to the primary cell when the cell configuration information carried by the second RRC connection reconfiguration message does not include configuration information of the target secondary primary cell.

In a possible implementation method, the transceiver unit 1020 is further configured to receive the second RRC connection reconfiguration message before sending a third RRC reconfiguration complete message to the primary cell, where the third RRC reconfiguration complete message is used to indicate an end of the conditional secondary primary cell change procedure.

In a possible implementation method, the transceiver unit 1020 is further configured to receive the second RRC connection reconfiguration message before sending the third RRC reconfiguration complete message to the primary cell.

In one possible implementation method, the transceiver unit 1020 is further configured to receive the second RRC connection reconfiguration message within a first duration after sending a third RRC reconfiguration complete message to the primary cell.

In one possible implementation method, the transceiver unit 1020 is further configured to receive the second RRC connection reconfiguration message within a first duration after sending a third RRC reconfiguration complete message to the primary cell; the first duration is less than the time consumed by the primary cell to receive the RRC reconfiguration complete message and issue a new RRC configuration.

In a possible implementation method, the processing unit 1010 further includes a timer, and is configured to start the timer after the transceiver unit sends the third RRC connection reconfiguration message, where a duration of the timer is the first duration.

In a possible implementation method, the processing unit 1010 further includes synchronization information for determining whether the cell configuration information carried by the second RRC connection reconfiguration message includes the target PSCell.

In the above embodiments, the transceiver 1020 may be divided into a single receiver and a single transmitter, and each may have functions of receiving and transmitting, which is not limited herein.

Optionally, the communication device may further include a storage unit, where the storage unit is configured to store data or instructions (which may also be referred to as codes or programs), and the respective units may interact or be coupled with the storage unit to implement the corresponding methods or functions. The coupling in the embodiments of the present application is an indirect coupling or communication connection between devices, units, or modules, which may be in electrical, mechanical, or other forms for information interaction between the devices, units, or modules.

In this embodiment of the present application, the division of units in the communication device is merely a division of logic functions, and may be fully or partially integrated into one physical entity or may be physically separated. And the units in the communication device may all be implemented in the form of software calls via the processing element; or can be realized in hardware; it is also possible that part of the units are implemented in the form of software, which is called by the processing element, and part of the units are implemented in the form of hardware. For example, each unit may be a processing element that is set up separately, may be implemented integrally in a certain chip of the communication device, or may be stored in a memory in the form of a program, and the function of the unit may be called and executed by a certain processing element of the communication device. Furthermore, all or part of these units may be integrated together or may be implemented independently. The processing element described herein, which may also be referred to as a processor, may be an integrated circuit with signal processing capabilities. In implementation, each step of the above method or each unit above may be implemented by an integrated logic circuit of hardware in a processor element or in the form of software called by a processing element.

In one example, the unit in any of the above communication devices may be one or more integrated circuits configured to implement the above methods, such as: one or more specific integrated circuits (application specific integrated circuit, ASIC), or one or more microprocessors (digital signal processor, DSP), or one or more field programmable gate arrays (field programmable gate array, FPGA), or a combination of at least two of these integrated circuit forms. For another example, when the unit in the communication device may be implemented in the form of a processing element scheduler, the processing element may be a general purpose processor, such as a central processing unit (central processing unit, CPU) or other processor that may invoke the program. For another example, the units may be integrated together and implemented in the form of a system-on-a-chip (SOC).

Referring to fig. 11, a schematic structural diagram of a wireless communication device according to an embodiment of the present application is provided, where the wireless communication device may be a wireless communication device or a network device, or may be a chip or a circuit, for example, may be disposed on the chip or the circuit of the wireless communication device, and further, for example, may be disposed on the chip or the circuit of the network device, so as to implement the method in the foregoing method embodiment. As shown in fig. 11, the communication apparatus 1100 includes: processor 1110 and transceiver 1130, optionally, the communication device 1100 further includes a memory 1120, this memory 1120 not being necessary represented by a dashed box in the figure. The transceiver 1130 is used to enable communication with other devices. Wherein processor 1110, memory 1120, and transceiver 1130 are in communication with data through a bus implementation connection.

It should be appreciated that the processor 1110 may be a chip. For example, the processor 1110 may be a field programmable gate array (field programmable gate array, FPGA), an application specific integrated chip (application specific integrated circuit, ASIC), a system on chip (SoC), a central processing unit (central processor unit, CPU), a network processor (network processor, NP), a digital signal processing circuit (digital signal processor, DSP), a microcontroller (micro controller unit, MCU), a programmable controller (programmable logic device, PLD) or other integrated chip.

In implementation, the steps of the methods described above may be performed by integrated logic circuitry in hardware or instructions in software in processor 1110. The steps of a method disclosed in connection with the embodiments of the present application may be embodied directly in hardware processor execution or in a combination of hardware and software modules in the processor 1110. The software modules may be located in a random access memory, flash memory, read only memory, programmable read only memory, or electrically erasable programmable memory, registers, etc. as well known in the art. The storage medium is located in the memory 1120, and the processor 1110 reads information in the memory 1120 and performs the steps of the above method in combination with its hardware.

In particular, the functions of the processing unit 1010 in fig. 10 and the implementation procedure thereof can be implemented by the processor 1110 in the communication apparatus 1100 shown in fig. 11 calling computer executable instructions stored in the memory 1120. Alternatively, the functions/implementation of the transceiver unit 1020 in fig. 10 may be implemented by the transceiver 1130 in the communication apparatus 1100 shown in fig. 11.

It should be noted that the processor 1110 in the embodiment of the present application may be an integrated circuit chip with signal processing capability. In implementation, the steps of the above method embodiments may be implemented by integrated logic circuits of hardware in a processor or instructions in software form. The processor may be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, or discrete hardware components. The disclosed methods, steps, and logic blocks in the embodiments of the present application may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of a method disclosed in connection with the embodiments of the present application may be embodied directly in hardware, in a decoded processor, or in a combination of hardware and software modules in a decoded processor. The software modules may be located in a random access memory, flash memory, read only memory, programmable read only memory, or electrically erasable programmable memory, registers, etc. as well known in the art. The storage medium is located in a memory, and the processor reads the information in the memory and, in combination with its hardware, performs the steps of the above method.

In embodiments of the present application, memory 1120 may be volatile memory or nonvolatile memory, or may include both volatile and nonvolatile memory. The nonvolatile memory may be a read-only memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an electrically Erasable EPROM (EEPROM), or a flash memory. The volatile memory may be random access memory (random access memory, RAM) which acts as an external cache. By way of example and not limitation, many forms of RAM are available, such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM). It should be noted that the memory of the systems and methods described herein is intended to comprise, without being limited to, these and any other suitable types of memory.

In the case where the communication device 1100 corresponds to the wireless communication device in the above-described method, the communication device may include a processor 1110, a transceiver 1130, and a memory 1320. The memory 1120 is configured to store instructions and the processor 1110 is configured to execute the instructions stored by the memory 1120 to implement steps performed by the wireless communication device in any one or more of the corresponding methods shown in fig. 6-7.

Those of ordinary skill in the art will appreciate that: the first, second, etc. numbers in the embodiments of the present application are merely for convenience of description and are not intended to limit the scope of the embodiments of the present application, and indicate the sequence. "and/or", describes an association relationship of an association object, and indicates that there may be three relationships, for example, a and/or B, and may indicate: a exists alone, A and B exist together, and B exists alone. The character "/" generally indicates that the context-dependent object is an "or" relationship. "at least one" means one or more. At least two means two or more. "at least one," "any one," or the like, refers to any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one of a, b, or c (species ) may represent: a, b, c, a-b, a-c, b-c, or a-b-c, wherein a, b, c may be single or plural. "plurality" means two or more, and the like.

It should be understood that, in various embodiments of the present application, the sequence numbers of the foregoing processes do not mean the order of execution, and the order of execution of the processes should be determined by the functions and internal logic thereof, and should not constitute any limitation on the implementation process of the embodiments of the present application.

The technical solution provided in the embodiments of the present application may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may 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 loaded and executed on a computer, produces a flow or function in accordance with embodiments of the present application, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, a terminal device, a network device, an artificial intelligence device, or other programmable apparatus. The computer instructions may be stored in or transmitted from one computer-readable storage medium to another, for example, by wired (e.g., coaxial cable, optical fiber, digital Subscriber Line (DSL)), or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device including one or more servers, data centers, etc. that can be integrated with the available medium. The usable medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a Solid State Disk (SSD)), or the like.

In the embodiments of the present application, the embodiments may be referred to each other, for example, methods and/or terms between method embodiments may be referred to each other, for example, functions and/or terms between apparatus embodiments and method embodiments may be referred to each other.

The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the scope of the present invention should be included in the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

A method of wireless communication, comprising:

receiving a first radio link control (RRC) connection reconfiguration message, wherein the first RRC connection reconfiguration message carries synchronization information of candidate auxiliary main cells and triggering condition information of condition auxiliary main cell change;

transmitting a first RRC reconfiguration complete message, wherein the first RRC reconfiguration complete message is used for responding to the first RRC connection reconfiguration message;

receiving a second RRC connection reconfiguration message from the main cell in the process of executing the conditional auxiliary main cell change, wherein the second RRC connection reconfiguration message carries cell configuration information;

Sending a second RRC reconfiguration complete message to the primary cell, wherein the second RRC reconfiguration complete message is used for responding to the second RRC connection reconfiguration message;

when the cell configuration information carried by the second RRC connection reconfiguration message comprises the configuration information of a target auxiliary main cell, initiating a random access process to the target auxiliary main cell;

the configuration information is used for indicating to synchronize to the target auxiliary main cell.
The method as recited in claim 1, further comprising:

when the cell configuration information carried by the second RRC connection reconfiguration message does not comprise the configuration information of the target auxiliary main cell, sending an auxiliary cell group failure information message to the main cell;

the configuration information is used for indicating to synchronize to the target auxiliary main cell.
The method according to any one of claims 1 to 2, characterized in that:

in the process of performing the conditional auxiliary primary cell change, receiving a second RRC connection reconfiguration message from the primary cell, including:

and before sending a third RRC reconfiguration complete message to the main cell, receiving the second RRC connection reconfiguration message, wherein the third RRC reconfiguration complete message is used for indicating the end of the conditional auxiliary main cell changing flow.
The method according to any one of claims 1 to 2, characterized in that:

in the process of performing the conditional auxiliary primary cell change, receiving a second RRC connection reconfiguration message from the primary cell, including:

and receiving the second RRC connection reconfiguration message in a first time period after the third RRC reconfiguration completion message is sent to the main cell.
The method according to claim 4, wherein:

the first time period is less than the time period that the primary cell receives the RRC reconfiguration complete message and issues a new RRC configuration.
The method according to claim 5, wherein:

the first duration is a fixed value ranging in value from 30 to 50 milliseconds.
The method according to any one of claims 1 to 6, further comprising:

and determining whether the cell configuration information carried by the second RRC connection reconfiguration message comprises the synchronous information of the target auxiliary main cell according to whether the second RRC reconfiguration completion message comprises a sequence number indicating the auxiliary cell group and a reconfigurationWithSync field.
A wireless communications apparatus, comprising:

a processing unit and a receiving and transmitting unit;

wherein, the processing unit is used for controlling the receiving and transmitting unit, the receiving and transmitting unit is used for:

Receiving a first RRC connection reconfiguration message, wherein the first RRC connection reconfiguration message carries synchronization information of candidate auxiliary main cells and triggering condition information of condition auxiliary main cell change;

transmitting a first RRC reconfiguration complete message, wherein the first RRC reconfiguration complete message is used for responding to the first RRC connection reconfiguration message;

receiving a second RRC connection reconfiguration message from the main cell in the process of executing the conditional auxiliary main cell change, wherein the second RRC connection reconfiguration message carries cell configuration information;

sending a second RRC reconfiguration complete message to the primary cell, wherein the second RRC reconfiguration complete message is used for responding to the second RRC connection reconfiguration message;

and when the cell configuration information carried by the second RRC connection reconfiguration message comprises the configuration information of the target auxiliary main cell, initiating a random access process to the target auxiliary main cell.
The apparatus according to claim 8, wherein:

and the receiving and transmitting unit is used for transmitting a secondary cell group failure information message to the primary cell when the cell configuration information carried by the second RRC connection reconfiguration message does not include the configuration information of the target secondary primary cell.
The apparatus according to any one of claims 8 to 9, wherein:

The receiving and transmitting unit is configured to receive a second RRC connection reconfiguration message from the primary cell in the performing condition-assisted primary cell change procedure, and includes:

the transceiver unit is configured to receive the second RRC connection reconfiguration message before sending a third RRC reconfiguration complete message to the primary cell, where the third RRC reconfiguration complete message is used to indicate an end of the conditional auxiliary primary cell change procedure.
The apparatus according to any one of claims 8 to 9, wherein:

the receiving and transmitting unit is configured to receive a second RRC connection reconfiguration message from the primary cell in the performing condition-assisted primary cell change procedure, and includes:

the transceiver unit is configured to receive the second RRC connection reconfiguration message within a first duration after sending a third RRC reconfiguration complete message to the primary cell.
The apparatus according to any one of claims 11, wherein:

the transceiver unit is further configured to receive the second RRC connection reconfiguration message within a first duration after sending a third RRC reconfiguration complete message to the primary cell;

the first duration is less than the time consumed by the primary cell to receive the RRC reconfiguration complete message and issue a new RRC configuration.
The apparatus according to any one of claims 12, wherein:

the processing unit is further configured to start a timer after the transceiver unit sends the third RRC connection reconfiguration message, where a duration of the timer is the first duration;

the first duration is less than the time consumed by the primary cell to receive the RRC reconfiguration complete message and issue a new RRC configuration.
The method according to claim 13, wherein:

the processing unit is further configured to configure the first duration of the timer to be a fixed value having a value in the range of 30 to 50 milliseconds.
The apparatus according to any one of claims 9 to 14, wherein:

the processing unit is further configured to determine, according to whether the second RRC reconfiguration complete message includes a sequence number indicating the secondary cell group and a ReconfigurationWithSync field, whether cell configuration information carried in the second RRC connection reconfiguration message includes synchronization information of the target secondary primary cell.
A wireless communications apparatus, comprising:

a processor and a memory, wherein the memory is for storing program instructions, the processor being for executing the program instructions in the memory to implement the method of any one of claims 1 to 8.
A wireless communications apparatus, comprising:

a processing circuit and an interface circuit; wherein,

the interface circuit is configured to couple with a memory external to the wireless communication device and provide a communication interface for the processing circuit to access the memory;

the processing circuitry is configured to execute program instructions in the memory to implement the method of any of claims 1 to 8.
A computer-readable storage medium, characterized by:

the computer readable storage medium having stored therein a program code which, when executed by a processor, implements the method of any of claims 1 to 8.
A computer program product, characterized by:

the computer program product comprising program code for implementing the method of any of claims 1 to 8 when executed by a processor.