WO2024093721A1

WO2024093721A1 - Communication method, device and system

Info

Publication number: WO2024093721A1
Application number: PCT/CN2023/126150
Authority: WO
Inventors: 李娇娇; 李秉肇; 强鹂; 毛颖超; 大卫•勒孔特
Original assignee: 华为技术有限公司
Priority date: 2022-11-04
Filing date: 2023-10-24
Publication date: 2024-05-10
Also published as: CN117998495A

Abstract

Provided are a communication method, device and system, which relate to the field of wireless communication, and in particular to a handover process in a wireless communication system, and can solve the problem in the prior art regarding how a terminal device responds to the configuration of a candidate cell after receiving the configuration of the candidate cell, thereby better ensuring communication between terminal devices. The method can comprise: receiving a first message, wherein the first message carries first information, and the first information comprises configuration information of M candidate cells, where M is a positive integer greater than 1; sending a second message, wherein the second message carries M pieces of second information, and the M pieces of second information correspond to the configuration information of the M candidate cells; and accessing a first cell, wherein the first cell belongs to the M candidate cells.

Description

Communication method, device and system

Technical Field

The embodiments of the present application relate to the field of communications, and more specifically, to a communication method, device, and system.

Background technique

In a wireless communication system, when a user equipment (UE) is in a service connection state and maintains service, it moves from one cell to another. In order to ensure the continuity of UE communication, switching is required.

At present, the fifth-generation (5G) radio access network (RAN) architecture considers the use of independent deployment of centralized units (CU) and distributed units (DU) in base stations to better meet the needs of various scenarios and applications. In the CU-DU separated base station deployment, in order to reduce the switching delay and further enhance business continuity, the 5G system considers the use of layer 1 and/or layer 2 (L1/L2) triggered switching. Among them, layer 1 includes the physical (physical layer, PHY) layer, and layer 2 includes the radio link control (radio link control, RLC) layer, the media access control (media access control, MAC) layer, and the packet data convergence protocol (packet data convergence protocol, PDCP) layer.

In the L1/L2 triggered mobility process, the terminal device needs to first obtain the pre-configuration information of the candidate cell through the Radio Resource Control (RRC) reconfiguration message to facilitate the terminal device to access the candidate cell. After the terminal device receives the configuration of the candidate cell, how to respond to the configuration of the candidate cell to improve communication efficiency is an urgent problem to be solved.

Summary of the invention

The present application provides a communication method, apparatus and system, which can provide better configuration information when a terminal device performs cell switching, thereby improving communication efficiency.

In a first aspect, a communication method is provided, which can be executed by a terminal device, or can also be executed by a component (such as a chip or circuit) of the terminal device, which is not limited in this application. For ease of description, the following description is taken as an example of execution by a terminal device.

The method may include: receiving a first message, the first message carrying first information, the first information including configuration information of M candidate cells, M being a positive integer greater than 1; sending a second message, the second message carrying M second information, the M second information corresponding to the configuration information of the M candidate cells; accessing a first cell, the first cell belonging to the M candidate cells.

Through the above scheme, the terminal device determines the information that needs to be reported to the candidate cell based on the configuration information of the candidate cell, and includes the reported information in the second message sent to the network device, which is used for the candidate cell to better configure the terminal device in the future, ensuring that the terminal device can be provided with better configuration information after accessing the candidate cell, thereby improving communication efficiency.

In one possible design, the first message is a radio resource control RRC reconfiguration message, and the second message is an RRC reconfiguration completion message.

In one possible design, the second information includes one or more of the following information:

Uplink DC parameters;

Conditional primary and secondary cells PSCell add or change related parameters;

Measurement report available indication;

Measuring gap requirement indication.

By including the above parameters in the second information, the network device can better configure the terminal after receiving the above information. resources or measurements of equipment to improve communication efficiency.

In one possible design, the second message includes RRC reconfiguration completion messages of M candidate cells, and the RRC reconfiguration completion messages of the M candidate cells carry the M second information. In one possible design, the RRC reconfiguration completion messages of the M candidate cells do not include an RRC processing identifier.

By not including the RRC processing identifier in the RRC reconfiguration completion message, the problem of the terminal device being unable to set the RRC processing identifier value is avoided, and the problem of the network device being unable to determine the corresponding RRC process or the corresponding erroneous RRC processing process after receiving the RRC processing identifier is also avoided.

In one possible design, first indication information is received, where the first indication information indicates access to the first cell.

In a second aspect, a communication method is provided, which can be executed by a network device, or can also be executed by a component (such as a chip or circuit) of the network device, which is not limited in this application. For ease of description, the following is an example of execution by a network device.

The method may include: sending a first message, the first message carrying first information, the first information including configuration information of M candidate cells, M being a positive integer greater than 1; receiving a second message, the second message carrying M second information, the M second information corresponding to the configuration information of the M candidate cells.

In one possible design, the first message is an RRC reconfiguration message, and the second message is an RRC reconfiguration completion message.

Uplink DC parameters;

Measurement report available indication;

Measuring gap requirement indication.

In one possible design, the second message includes an RRC reconfiguration completion message of M candidate cells, and the RRC reconfiguration completion message of the M candidate cells carries the M second information.

In one possible design, the RRC reconfiguration completion message of the M candidate cells does not include an RRC processing identifier.

In a third aspect, a communication method is provided, which can be executed by a terminal device, or can also be executed by a component (such as a chip or circuit) of the terminal device, which is not limited in this application. For ease of description, the following description is taken as an example of execution by a terminal device.

The method may include: receiving a third message, the third message including third information, the third information including configuration information of N candidate cells and N configuration identifiers, the N configuration identifiers are used to identify the configuration information of the N candidate cells, N is a positive integer; receiving second indication information, the second indication information is used to indicate access to a second cell, the second cell belongs to the N candidate cells; sending a fourth message, the fourth message including a first identifier; wherein the first identifier is used to indicate the configuration information of the second cell.

Through the above scheme, the configuration identifier is associated with the configuration information of the candidate cell, so that the candidate cell after switching can obtain the candidate cell or candidate cell configuration corresponding to the RRC reconfiguration completion message. On the one hand, it solves the problem that the candidate cell cannot obtain the RRC reconfiguration completion message due to the absence of the RRC reconfiguration message. On the other hand, it also associates the information sent by the terminal device with the target cell configuration, ensuring that the candidate cell can correctly configure the terminal device after the terminal device is switched to ensure normal communication. Compared with using the RRC processing identifier for association, the first identifier can have more values, This avoids the problem of limited network configuration caused by occupying a large number of RRC processing identifiers.

In one possible design, the third message is an RRC reconfiguration message, and the fourth message is an RRC reconfiguration completion message.

In a fourth aspect, a communication method is provided, which can be executed by a network device, or can also be executed by a component (such as a chip or circuit) of the network device, which is not limited in this application. For ease of description, the following is an example of execution by a network device.

The method may include: sending a third message, the third message including third information, the third information including configuration information of N candidate cells, N is a positive integer; sending second indication information, the second indication information is used to indicate that the terminal device accesses a second cell, the second cell belongs to the N candidate cells; receiving a fourth message, the fourth message including a first identifier; wherein the first identifier is used to indicate the configuration information of the second cell.

Through the above scheme, the configuration identifier is associated with the configuration information of the candidate cell, so that the candidate cell after switching can obtain the candidate cell or candidate cell configuration corresponding to the RRC reconfiguration completion message. On the one hand, it solves the problem that the candidate cell cannot obtain the RRC reconfiguration completion message due to the lack of RRC reconfiguration message. On the other hand, it also associates the information sent by the terminal device with the target cell configuration, ensuring that the candidate cell can correctly configure the terminal device after the terminal device is switched to ensure normal communication. Compared with using the RRC processing identifier for association, the first identifier can have more values, avoiding the problem of limited network configuration caused by occupying more RRC processing identifiers.

In a fifth aspect, a communication method is provided, which can be executed by a terminal device, or can also be executed by a component (such as a chip or circuit) of the terminal device, and this application does not limit this. For ease of description, the following is an example of execution by a terminal device.

The method may include: receiving a fifth message, the fifth message including configuration information of L candidate cells, where L is a positive integer; if the third cell is accessed for the first time after receiving the fifth message, sending a first RRC reconfiguration completion message, the first RRC reconfiguration completion message including configuration information corresponding to the third cell, and the third cell belongs to the L candidate cells.

Through the above solution, the sending of RRC messages in the subsequent switching process is reduced, the problem of signaling overhead caused by information redundancy is avoided, and the consumption of air interface resources is reduced.

In one possible design, it is evaluated that an execution condition of the third cell is met, and the third cell is accessed.

In one possible design, third indication information is received, where the third indication information indicates access to the third cell.

In one possible design, if it is not the first time to access the third cell after receiving the fifth message, a second RRC reconfiguration completion message is sent, and the second RRC reconfiguration completion message only includes the RRC processing identifier; or, if it is not the first time to access the third cell after receiving the fifth message, the RRC reconfiguration completion message is not sent.

In a possible design, if it is not the first time to access the third cell after receiving the fifth message, a second RRC reconfiguration completion message is sent, and the second RRC reconfiguration completion message does not include the first parameter.

In this way, when a cell is not accessed for the first time, repeated reporting of some parameters is reduced, signaling overhead is reduced, and transmission resources are saved.

In one possible design, if the first parameter does not change, a second RRC reconfiguration complete message is sent, and the second RRC reconfiguration complete message does not include the first parameter; alternatively, if the first parameter does not change, the RRC reconfiguration complete message is not sent.

In this way, when the first parameter does not change, repeated reporting of some parameters is reduced, and signaling overhead is reduced. Saves transmission resources.

In one possible design, the first parameter is whether to need to measure at least one of a gap indication parameter and an uplink DC parameter.

When the first parameter bits are relatively large, this method can reduce repeated reporting of some parameters, reduce signaling overhead, and save transmission resources.

In one possible design, fourth indication information is received, and the fourth indication information indicates that the first parameter is not carried in the first RRC reconfiguration completion message or the second RRC reconfiguration completion message. In a sixth aspect, a communication method is provided, which may include: a first network device sends a fifth message to a terminal device, and the fifth message includes configuration information of L candidate cells, where L is a positive integer; if the terminal device accesses the third cell for the first time after receiving the fifth message, the terminal device sends a first RRC reconfiguration completion message to the first network device, and the first RRC reconfiguration completion message includes configuration information corresponding to the third cell, and the third cell belongs to the L candidate cells.

The first network device in the method may be a network device, or may be a component of a network device (such as a chip or circuit). The terminal device in the method may be a terminal device or a component of a terminal device (such as a chip or circuit).

In one possible design, the terminal device evaluates that the execution conditions of the third cell are met, and accesses the third cell.

In one possible design, the first network device sends the third indication information to the terminal device, and the third indication information instructs the terminal device to access the third cell.

In one possible design, if it is not the first time that the terminal device accesses the third cell after receiving the fifth message, the terminal device sends a second RRC reconfiguration completion message to the first network device, and the second RRC reconfiguration completion message only includes an RRC processing identifier; or, if it is not the first time that the terminal device accesses the third cell after receiving the fifth message, the terminal device does not send an RRC reconfiguration completion message.

In a possible design, if it is not the first time that the terminal device accesses the third cell after receiving the fifth message, the terminal device sends a second RRC reconfiguration completion message to the first network device, and the second RRC reconfiguration completion message does not include the first parameter.

In one possible design, if the first parameter does not change, the terminal device sends a second RRC reconfiguration completion message to the first network device, and the second RRC reconfiguration completion message does not include the first parameter; or, if the first parameter does not change, the terminal device does not send an RRC reconfiguration completion message.

In this way, when the first parameter does not change, repeated reporting of some parameters is reduced, signaling overhead is reduced, and transmission resources are saved.

In one possible design, the first network device sends fourth indication information to the terminal device, and the fourth indication information indicates that the terminal device does not carry the first parameter in the first RRC reconfiguration completion message or the second RRC reconfiguration completion message.

In the seventh aspect, a communication method is provided, which may include: a first network device sends a fifth message to a terminal device, the fifth message including configuration information of L candidate cells, where L is a positive integer; if the terminal device accesses a third cell for the first time after receiving the fifth message, the terminal device sends a first RRC reconfiguration completion message to a second network device, the first RRC reconfiguration completion message including configuration information corresponding to the third cell, and the third cell belongs to the L candidate cells; the second network device is the network device to which the third cell belongs.

The first network device or the second network device in the method may be a network device, or may be a component of a network device (such as a chip or circuit). The terminal device in the method may be a terminal device or a component of a terminal device (such as a chip or circuit).

In one possible design, if it is not the first time that the terminal device accesses the third cell after receiving the fifth message, the terminal device sends a second RRC reconfiguration completion message to the second network device, and the second RRC reconfiguration completion message only includes the RRC processing identifier; or, if it is not the first time that the terminal device accesses the third cell after receiving the fifth message, the terminal device does not send an RRC reconfiguration completion message.

In one possible design, if it is not the first time that the terminal device accesses the third cell after receiving the fifth message, the terminal device sends a second RRC reconfiguration completion message to the second network device, and the second RRC reconfiguration completion message does not include the first parameter.

In one possible design, if the first parameter does not change, the terminal device sends a second RRC reconfiguration completion message to the second network device, and the second RRC reconfiguration completion message does not include the first parameter; or, if the first parameter does not change, the terminal device does not send an RRC reconfiguration completion message.

In an eighth aspect, a communication method is provided, which can be executed by a terminal device, or can also be executed by a component (such as a chip or circuit) of the terminal device, and this application does not limit this. For ease of description, the following is an example of execution by a terminal device.

The method may include: receiving a fifth message, the fifth message including configuration information of L candidate cells, where L is a positive integer; if it is not the first time to access the third cell after receiving the fifth message, sending a second RRC reconfiguration completion message, the second RRC reconfiguration completion message does not include the first parameter, and the third cell belongs to the L candidate cells.

In one possible design, if it is not the first time to access the third cell after receiving the fifth message and the first parameter has not changed, a second RRC reconfiguration completion message is sent, and the first parameter is not included in the second RRC reconfiguration completion message; or, if it is not the first time to access the third cell after receiving the fifth message and the first parameter has not changed, no RRC reconfiguration completion message is sent.

In one possible design, fourth indication information is received, and the fourth indication information indicates that the first parameter is not carried in the second RRC reconfiguration completion message.

In the ninth aspect, a communication method is provided, which may include: a first network device sends a fifth message to a terminal device, the fifth message including configuration information of L candidate cells, where L is a positive integer; if the terminal device does not access the third cell for the first time after receiving the fifth message, the terminal device sends a second RRC reconfiguration completion message to the first network device, the second RRC reconfiguration completion message does not include the first parameter, and the third cell belongs to the L candidate cells.

In one possible design, if it is not the first time that the terminal device accesses the third cell after receiving the fifth message, and the first parameter has not changed, the terminal device sends a second RRC reconfiguration completion message to the first network device, and the second RRC reconfiguration completion message does not include the first parameter; or, if it is not the first time that the terminal device accesses the third cell after receiving the fifth message, and the first parameter has not changed, the terminal device does not send an RRC reconfiguration completion message.

In one possible design, the first network device sends fourth indication information to the terminal device, and the fourth indication information indicates that the terminal device does not carry the first parameter in the second RRC reconfiguration completion message.

In the tenth aspect, a communication method is provided, which may include: a first network device sends a fifth message to a terminal device, the fifth message including configuration information of L candidate cells, where L is a positive integer; if the terminal device does not access the third cell for the first time after receiving the fifth message, the terminal device sends a second RRC reconfiguration completion message to the second network device, the second RRC reconfiguration completion message does not include the first parameter, and the third cell belongs to the L candidate cells.

In one possible design, if it is not the first time that the terminal device accesses the third cell after receiving the fifth message, and the first parameter has not changed, the terminal device sends a second RRC reconfiguration completion message to the second network device, and the second RRC reconfiguration completion message does not include the first parameter; or, if it is not the first time that the terminal device accesses the third cell after receiving the fifth message, and the first parameter has not changed, the terminal device does not send an RRC reconfiguration completion message.

Accordingly, the present application also provides a communication device, which can implement any of the communication methods described in aspects 1 to 7. For example, the device can be a terminal device or a network device, or other device capable of implementing the above communication method, which can implement the above method through software, hardware, or hardware executing corresponding software.

In one possible design, the device may include a processor and a memory. The processor is configured to support the device to perform the corresponding functions of the method described in any one of the above aspects. The memory is used to couple with the processor, and stores the necessary program instructions and data of the device. In addition, the device may also include a communication interface for supporting communication between the device and other devices. The communication interface may be a transceiver or a transceiver circuit.

On the other hand, an embodiment of the present application provides a communication system, which includes the communication device described in the above aspects.

Another aspect of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores instructions, and when the computer-readable storage medium is run on a computer, the computer executes the methods described in the above aspects.

Another aspect of the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the methods described in the above aspects.

The present application also provides a chip system, which includes a processor and may also include a memory, for implementing the method described in any of the above aspects.

Any of the above-mentioned devices, computer storage media, computer program products, chip systems, or communication systems are used to execute the corresponding methods provided above. Therefore, the beneficial effects that can be achieved can refer to the corresponding methods provided above. The beneficial effects of the corresponding scheme in the law will not be elaborated here.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a network architecture provided in an embodiment of the present application.

FIG2 is a schematic diagram of a network architecture of a network device provided in an embodiment of the present application.

FIG3 is a schematic diagram of CU-DU separation of a network device provided in an embodiment of the present application.

FIG4 is a schematic diagram of a dual connection scenario provided in an embodiment of the present application.

FIG. 5 is a schematic diagram of a switching interaction provided in an embodiment of the present application.

FIG6 is a schematic diagram of an interaction of L1/L2 triggered mobility between DUs within a CU provided in an embodiment of the present application.

FIG. 7 is a schematic diagram of an interaction of intra-CU and intra-DU L1/L2 triggered mobility provided by an embodiment of the present application.

FIG8 is a schematic diagram of a CPA interaction provided in an embodiment of the present application.

FIG. 9 is a schematic diagram of an interaction of CPC provided in an embodiment of the present application.

FIG. 10 is a schematic diagram of an interaction of continuous L1/L2 triggered mobility provided in an embodiment of the present application.

FIG11 is a schematic diagram of a continuous CPC scenario provided in an embodiment of the present application.

FIG12 is a schematic diagram of a continuous CPC interaction provided in an embodiment of the present application.

FIG. 13 is an interactive schematic diagram of a communication method provided in an embodiment of the present application.

FIG. 14 is a schematic diagram of another interaction of L1/L2 triggered mobility provided in an embodiment of the present application.

FIG. 15 is an interactive schematic diagram of another communication method provided in an embodiment of the present application.

FIG. 16 is a schematic diagram of another interaction of L1/L2 triggered mobility provided in an embodiment of the present application.

FIG. 17 is an interactive schematic diagram of yet another communication method provided in an embodiment of the present application.

FIG18 is an interactive schematic diagram of another communication method provided in an embodiment of the present application.

FIG19 is a schematic diagram of a communication device provided in an embodiment of the present application.

FIG20 is a schematic diagram of another communication device provided in an embodiment of the present application.

FIG21 is a schematic diagram of another communication device provided in an embodiment of the present application.

Figure 22 is a schematic diagram of a communication system provided in an embodiment of the present application.

Detailed ways

The technical solution in this application will be described below in conjunction with the accompanying drawings.

The technical solutions of the embodiments of the present application can be applied to various communication systems, for example: Global System of Mobile communication (GSM) system, Code Division Multiple Access (CDMA) system, Wideband Code Division Multiple Access (WCDMA) system, General Packet Radio Service (GPRS), Long Term Evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), universal mobile telecommunication system (UMTS), worldwide interoperability for microwave access (WiMAX) communication system, fifth generation (5G) mobile communication system or new radio (NR). Among them, the 5G mobile communication system can be a non-standalone (NSA) or an independent network (SA).

The technical solution provided in this application can also be applied to machine type communication (MTC), long term evolution-machine (LTE-M), device-to-device (D2D) network, machine-to-machine (M2M) network, Internet of Things (IoT) network or other networks. Among them, IoT network can include Internet of Vehicles, for example. Among them, the communication mode in the Internet of Vehicles system Collectively referred to as vehicle to other devices (vehicle to X, V2X, X can represent anything), for example, the V2X may include: vehicle to vehicle (vehicle to vehicle, V2V) communication, vehicle to infrastructure (vehicle to infrastructure, V2I) communication, vehicle to pedestrian (vehicle to pedestrian, V2P) or vehicle to network (vehicle to network, V2N) communication, etc.

The technical solution provided in this application can also be applied to future communication systems, such as the sixth generation (6G) mobile communication system. This application does not limit this.

In the embodiments of the present application, the terminal device may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device. The terminal can be widely used in various scenarios, for example, device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IOT), virtual reality, augmented reality, industrial control, automatic driving, telemedicine, smart grid, smart furniture, smart office, smart wear, smart transportation, smart city, etc. The terminal may be a mobile phone, a tablet computer, a computer with wireless transceiver function, a wearable device, a vehicle, a drone, a helicopter, an airplane, a ship, a robot, a mechanical arm, a smart home device, etc. The embodiments of the present application do not limit the specific technology and specific device form adopted by the terminal.

A terminal device can be a device that provides voice/data connectivity to users, such as a handheld device with wireless connection function, a vehicle-mounted device, etc. At present, some examples of terminals can be: mobile phones, tablet computers, computers with wireless transceiver functions (such as laptops, PDAs, etc.), mobile Internet devices (mobile internet devices, MIDs), virtual reality (virtual reality, VR) devices, augmented reality (augmented reality, AR) devices, wireless terminals in industrial control (industrial control), wireless terminals in self-driving, wireless terminals in remote medical, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, etc. Wireless terminals in smart cities, wireless terminals in smart homes (for example, home appliances such as televisions, smart boxes, game consoles), cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication functions, computing devices or other processing devices connected to wireless modems, vehicle-mounted devices, wearable devices, terminal devices in 5G networks, or terminal devices in future evolved public land mobile networks (PLMNs), etc.

Among them, wearable devices can also be called wearable smart devices, which are a general term for the intelligent design and development of wearable devices for daily wear using wearable technology, such as glasses, gloves, watches, clothing and shoes. Wearable devices are portable devices that are worn directly on the body or integrated into the user's clothes or accessories. Wearable devices are not only hardware devices, but also realize powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include full-featured, large-sized, and independent of smartphones to achieve complete or partial functions, such as smart watches or smart glasses, as well as those that only focus on a certain type of application function and need to be used in conjunction with other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

In addition, the terminal device can also be a terminal device in the Internet of Things (IoT) system. IoT is an important part of the future development of information technology. Its main technical feature is to connect objects to the network through communication technology, thereby realizing an intelligent network of human-machine interconnection and object-to-object interconnection. IoT technology can achieve massive connections, deep coverage, and terminal power saving through narrowband (NB) technology, for example.

In an embodiment of the present application, the terminal device may also be a vehicle or a complete vehicle, which can achieve communication through the Internet of Vehicles, or it may be a component located in the vehicle (for example, placed in the vehicle or installed in the vehicle), that is, a vehicle-mounted terminal device, a vehicle-mounted module or a vehicle-mounted unit (on-board unit, OBU).

In addition, terminal devices can also include sensors such as smart printers, train detectors, and gas stations. Their main functions include collecting data (part of the terminal equipment), receiving control information and downlink data from network devices, and sending electromagnetic waves to transmit uplink data to network devices.

In the embodiment of the present application, the network device can be any device with wireless transceiver function. The device includes but is not limited to: evolved Node B (eNB), radio network controller (RNC), Node B (NB), base station controller (BSC), base transceiver station (BTS), home base station (e.g., home evolved Node B, or home Node B, HNB), baseband unit (BBU), wireless fidelity (Wi-Fi), etc. i) The access point (AP), wireless relay node, wireless backhaul node, transmission point (TP) or transmission and reception point (TRP) in the system, and can also be a gNB in a 5G, such as NR, system, or a transmission point (TRP or TP), one or a group of (including multiple antenna panels) antenna panels of a base station in a 5G system, or a network node constituting a gNB or a transmission point, such as a baseband unit (BBU), or a distributed unit (DU), or a base station in a next generation communication 6G system, etc.

The network equipment provides services for the cell, and the terminal equipment communicates with the cell through the transmission resources (for example, frequency domain resources, or spectrum resources) allocated by the network equipment. The cell can belong to a macro base station (for example, macro eNB or macro gNB, etc.), or to a base station corresponding to a small cell. The small cell here may include: metro cell, micro cell, pico cell, femto cell, etc. These small cells have the characteristics of small coverage and low transmission power, and are suitable for providing high-speed data transmission services.

The following is an example description of a network architecture applicable to the embodiments of the present application.

Please refer to Figure 1, which is a schematic diagram of a network architecture provided by an embodiment of the present application. As shown in Figure 1, the network architecture may include a terminal device 101, a network device 102, and a core network device 103. Among them, the terminal device 101 can be connected to the network device 102 in a wireless manner, and can be connected to the core network device 103 through the network device 102. The terminal device 101 can be fixed or movable.

It should be noted that the number and type of network devices, terminal devices, and core network devices included in the network architecture shown in Figure 1 are merely examples, and the embodiments of the present application are not limited to this. For example, more or fewer terminal devices that communicate with network devices may also be included, for example, more or fewer core network devices that communicate with network devices may also be included. For the sake of simplicity, they are not described one by one in the accompanying drawings. In addition, in the network architecture shown in Figure 1, although network devices, terminal devices, and core network devices are shown, the application scenario may not be limited to network devices, terminal devices, and core network devices. For example, devices for carrying virtualized network functions may also be included. These are obvious to those skilled in the art and will not be described one by one here.

Further, please refer to Figure 2, which is a schematic diagram of the network architecture of a network device provided in an embodiment of the present application. As shown in Figure 2, the network device may also be referred to as an access network device, and the access network device may include a base station gNB. The access network device may be connected to the core network device through the NG interface, and the access network devices may be connected through the Xn-C interface. Among them, the gNB may adopt a CU-DU separation structure, and the CU and DU may be connected through the F1 interface. As shown in Figure 3, the CU includes a radio resource control (RRC) layer and a PDCP layer, and the DU includes an RLC layer, a medium access control (MAC) layer and a physical layer (PHY). The core network device may include an access and mobility management function (AMF) network element and a user plane function (UPF) network element.

gNB can also include active antenna unit (AAU). CU implements some functions of gNB, and DU implements some functions of gNB. For example, CU is responsible for processing non-real-time protocols and services. DU is responsible for processing physical layer protocols and real-time services. AAU implements some physical layer processing functions, RF processing and related functions of active antennas. Since the information of the RRC layer will eventually become the information of the PHY layer, or be converted from the information of the PHY layer, therefore, under this architecture, high-level signaling, such as RRC layer signaling, can also be considered to be sent by the DU, or by the DU and the CU. It can be understood that the network device can be a device including one or more of a CU node, a DU node, and an AAU node. In addition, the CU can be divided into a network device in the access network (radio access network, RAN), and the CU can also be divided into a network device in the core network (core network, CN), which is not limited in this application.

FIG4 is a schematic diagram of a dual-connectivity (DC) scenario applicable to an embodiment of the present application. Dual-connectivity or multi-connectivity (Multi-Radio Dual Connectivity, MR-DC) means that a terminal device can communicate with two network devices at the same time, and one of the two network devices can be an NR network device and the other can be an LTE network device, or both can be NR network devices. One network device is a master node (MN), and one network device is a secondary node (SN). As shown in FIG4, when dual-connectivity is combined with carrier aggregation (CA), each network device can include a cell group (CG). Among them, the cell group under the MN is a master cell group (MCG), and the cell group under the SN is a secondary cell group (SCG). The primary cell group may include one primary cell (PCell) and at least one secondary cell (SCell), and the secondary cell group may include one primary secondary cell (PSCell) and at least one secondary cell (SCell).

It should be understood that when dual connectivity is not combined with CA, there is only one primary cell under the primary station and only one primary and secondary cell under the secondary station. This scenario is also applicable to the embodiments of the present application.

It should be understood that for the sake of ease of description, FIG4 is illustrated by taking the example that each cell group includes 2 SCells.

In the DC scenario, the terminal device will have the process of adding or changing the PSCell. The addition of PSCell triggered by the terminal device is called conditional PSCell addition (CPA), and the change of PSCell triggered by the terminal device is called conditional PSCell change (CPC). Among them, CPA can be understood as the conditional addition of PSCell. When the terminal device meets the conditions for adding PSCell, the terminal device performs the process of adding PSCell. CPC can be understood as the conditional change of PSCell. When the terminal device meets the conditions for changing PSCell, the terminal device performs the process of changing PSCell. Specifically, as an example, CPA and CPC can also be collectively referred to as conditional PSCell addition and change (CPAC). That is, the network configuration will configure multiple candidate PSCells and send the CPAC configuration to the terminal device. The CPAC configuration includes the configuration of the multiple candidate PSCells and the corresponding execution conditions (execution condition). When the terminal device evaluates that the execution condition of a candidate PSCell is met, the terminal device can perform the process of adding or changing the PSCell. The cell that meets the execution condition can be called a selected cell.

After the terminal device completes the CPA or CPC process and establishes a connection with a candidate PSCell that meets the conditions (for example, a random access channel (RACH)), the terminal device will release the CPA configuration and/or CPC configuration. Therefore, before the network is reconfigured or the network is restarted, the terminal device cannot continue to use the CPA configuration and/or CPC configuration. In order to reduce the delay and signaling overhead of the secondary cell group change, the terminal device may not release the CPA configuration and/or CPC configuration. Before the network is reconfigured or the network is restarted, the terminal device continues to use the previously stored CPA configuration or CPC configuration, thereby continuing to execute the CPA or CPC process.

For ease of description, CPA or CPC may be collectively referred to as CPAC in this application. CPA configuration or CPC configuration may be collectively referred to as CPAC configuration.

The following is a definition of technical terms that may appear in the embodiments of the present application. The terms used in the implementation method section of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application.

(1) Cell, source cell, target cell, candidate cell

The network device may configure or deploy or control at least one cell.

In the handover scenario, the cell accessed by the terminal device before the handover is called the source cell, and the cell accessed by the terminal device after the handover is called the target cell. The source cell and the target cell may be cells configured by the same network device, or they may be cells configured by different network devices. For example, the network device is a base station. One example is that the source cell is cell 11 configured by base station 1, and the target cell is cell 12 configured by base station 1. Another example is that the source cell is cell 11 configured by base station 1, and the target cell is cell 21 configured by base station 2. For example, in a CU-DU separation architecture, the network device includes a CU and a DU. One example is that the source cell is cell 11 configured by DU1, and the target cell is cell 12 configured by DU1. Another example is that the source cell is cell 11 configured by DU1, and the target cell is cell 21 configured by DU2. DU1 and DU2 may belong to the same CU or different CUs.

In another example, the terminal may perform a change in the PSCell. In this example, the primary cell under the primary base station may remain unchanged. In one example, the source cell is cell 11 configured by secondary base station 1, and the target cell is cell 12 configured by secondary base station 1. In another example, the source cell is cell 11 configured by secondary base station 1, and the target cell is cell 21 configured by secondary base station 2.

The candidate cell is also referred to as a switching candidate cell or a target candidate cell or a candidate target cell, and the names are not limited in the embodiments of the present application. In some switching modes, for example, in the L1/L2-triggered mobility (LTM) or CPAC process described later, the network device can configure at least one candidate cell for the terminal device. In these switching modes, the target cell is a candidate cell among the at least one candidate cell.

(2) Source network device, target network device, candidate network device

In a switching scenario, the network device that the terminal device communicates with before switching is called the source network device, and the network device that the terminal device communicates with after switching is called the target network device.

The source network device and the target network device can be the same or different.

When the source network device and the target network device are the same, it is called a handover within the network device. For example, the network device is a base station, the source network device and the target network device are both base station 1, the source cell is cell 11 configured by base station 1, and the target cell is cell 12 configured by base station 1. The handover is a handover within the base station. For another example, the network device includes CU and DU. The source network device and the target network device are both DU1, the source cell is cell 11 configured by DU1, and the target cell is cell 12 configured by DU1. The handover is a handover within DU. For another example, the network device is an auxiliary base station, the source network device and the target network device are both auxiliary base station 1, the source cell is cell 11 configured by auxiliary base station 1, and the target cell is cell 12 configured by auxiliary base station 1. The handover is a handover within the auxiliary base station.

When the source network device and the target network device are different, it is called inter-network device handover or handover between different network devices. For example, the network device is a base station, the source cell is cell 11 configured by base station 1, the source network device is base station 1, the target cell is cell 21 configured by base station 2, and the target network device is base station 2. The handover is an inter-base station handover. For another example, the network device includes a CU and a DU. The source cell is cell 11 configured by DU1, the source network device is DU1, the target cell is cell 21 configured by DU2, and the target network device is DU2. The handover is an inter-DU handover. DU1 and DU2 may belong to the same CU or different CUs. For another example, the network device is a secondary base station, the source cell is cell 11 configured by secondary base station 1, the source network device is secondary base station 1, the target cell is cell 21 configured by secondary base station 2, and the target network device is secondary base station 2. The handover is an inter-secondary base station handover.

In some switching modes, such as L1/L2 triggered mobility or CPAC described later, the network device communicates with at least one candidate network device to negotiate at least one candidate cell configured for the terminal device. In these switching modes, the target network device is one of the at least one candidate network device.

(3) Switch

In a wireless communication system, when a terminal device moves from one cell to another, or due to network reasons, business load adjustment, equipment failure, etc., the terminal device may leave the source cell and access the target cell to ensure the terminal The continuity of communication between the device and the network. The above process is called "handoff".

In a possible implementation, the switching can be controlled by layer 3, namely, the RRC layer. Please refer to FIG5 , which is a schematic diagram of a switching interaction provided by an embodiment of the present application. As shown in FIG5 , the switching process can be as follows:

0. The source base station performs measurement configuration on the terminal device, and the terminal device performs measurement according to the measurement configuration and reports the measurement report;

1. The source base station makes a handover decision. The source base station can refer to the measurement results reported by the terminal device and/or its own handover algorithm to make a handover decision. For example, when the signal quality of the source cell is poor, but the signal quality of the target cell is good, the source base station determines to perform a handover;

2. The source base station sends a handover request message to the target base station. The request message transmits the necessary information for handover preparation, which at least includes the target cell ID, key, terminal ID in the source cell, basic access layer configuration, etc.

3. The target base station performs admission control;

4. The target base station sends a handover request confirmation message to the source base station. If the target base station confirms that the terminal device can access, it replies with a handover request confirmation message to the source cell, where the handover command sent to the terminal device can be included in the confirmation message in the form of an RRC container;

5. The source base station sends an RRC reconfiguration message (or handover command) to the terminal device. The message contains the information required to access the target cell, including at least the target cell identifier, the new terminal device identifier, the target cell security algorithm identifier, and may also carry the dedicated RACH resources for accessing the target cell;

6. After receiving the handover command, the terminal device performs synchronization with the target cell, for example, through a random access procedure (RACH);

7. The terminal device sends an RRC reconfiguration complete message to the target base station, which is used to confirm the successful completion of the RRC reconfiguration. The RRC reconfiguration complete message includes the information required by the target base station to configure the terminal device after the terminal device accesses, which can help the target base station better configure the resources or measurements of the terminal device.

The main contents included in the RRC reconfiguration complete message may be shown in Table 1. The information elements or fields in Table 1 are the information elements or fields currently included in the RRC reconfiguration complete message, and new fields may be introduced in the future, which is not limited in this application.

Table 1

Among them, the RRC processing identifier must be carried, and other information elements or fields except the RRC processing identifier are optional. As can be seen from the above table, the bit size of some parameters in the RRC reconfiguration complete message is very large. It can be understood that the bit size values in the above table are for example only and are not necessarily accurate values.

(4) L1/L2 triggered mobility

In one possible implementation, switching can be accomplished by L1/L2 triggered mobility. L1/L2 triggered mobility may also be referred to as L1/L2 switching, L1/L2 mobility, lower layer switching, lower layer mobility or L2 triggered mobility, etc., and the names are not limited in the embodiments of the present application. For scenarios with large amounts of data (such as extended reality (XR) services) or scenarios with frequent switching (such as frequency range 2 (FR2)), in order to reduce switching delays and interruption times and improve the user experience of the terminal, layer 1/layer 2 mobility is proposed. L1/L2 triggered mobility is to instruct the terminal to perform switching through L1 signaling or L2 signaling. Among them, L1 signaling can be downlink control information (downlink control information, DCI), and L2 signaling can be MAC control element (Media Access Control control element, MAC CE). The main idea of L1/L2 triggered mobility is that the network device selects one or more candidate cell configurations based on the measurement report reported by the terminal device, where the measurement report can be a layer 3 (L3) measurement report, and provides the terminal device with the configuration information of one or more candidate cells through pre-configuration information (which can be included in the RRC reconfiguration message). After receiving the configuration information of L1/L2 triggered mobility, the terminal device does not immediately perform the handover. The source network device determines to trigger L1/L2 triggered mobility based on the measurement report (such as L1 measurement report) reported by the terminal device. The source network device sends an L1/L2 triggered mobility cell change (cell switch) command to the terminal device through L1/L2 signaling, which indicates the target cell identity or target cell configuration of the terminal device switching, and optionally includes the target beam information of the target cell. The L1/L2 triggered mobility cell change command can also be called an L1/L2 switching command, or an L1/L2 triggered mobility command, or an L1/L2 triggered mobility MAC CE/DCI. The terminal device performs the handover process based on the instructions in the cell change command. L1/L2 triggered mobility can be limited to the same CU. There are many technical solutions for implementing L1/L2 triggered mobility, and several of them are listed below as examples:

Solution 1: L1/L2 triggered mobility between DUs within a CU (intra-CU inter-DU).

Please refer to Figure 6, which is a schematic diagram of an interaction of L1/L2 triggered mobility between DUs in a CU provided by an embodiment of the present application. As shown in Figure 6, the process of L1/L2 triggered mobility between DUs in a CU includes:

0. The terminal device performs measurement according to the measurement configuration and reports a measurement report; the measurement configuration and report may be an L3 measurement configuration and report, and may be configured by the CU;

1. The base station (e.g., CU) determines the L1/L2 triggered mobility configuration decision (or handover preparation decision). The base station determines to perform L1/L2 triggered mobility and determines the candidate cells for L1/L2 triggered mobility. The base station determines the configuration decision or candidate cells by referring to the reporting results of the terminal device and/or its own handover algorithm;

2. The CU sends a terminal device context establishment request message to multiple candidate DUs. The multiple candidate DUs may be DUs to which multiple candidate cells belong;

3. The candidate DU sends a terminal device context establishment request confirmation message to the CU. If the candidate DU confirms that the terminal device can be connected, it replies to the CU with a terminal device context establishment request confirmation message, which may include the configuration information of the candidate cell;

4. The base station (e.g., CU) sends an RRC reconfiguration message to the terminal device, which includes L1/L2 triggered mobility preconfiguration information, and the L1/L2 triggered mobility preconfiguration information includes configuration information of one or more candidate cells. Optionally, the RRC reconfiguration message may also include configuration information of the source cell. The configuration information of each candidate cell may be sent in one of the following ways:

a) The configuration information of each candidate cell is included in an RRC reconfiguration message. That is, the RRC reconfiguration message sent by the base station to the terminal device in step 4 includes one or more RRC reconfiguration messages, each of which includes the configuration information of one or more candidate cells;

b) The configuration information of each candidate cell is contained in an information element (IE). That is, the RRC reconfiguration message sent by the base station to the terminal device in the fourth step contains one or more IEs, each containing the configuration information of one or more candidate cells. For example, the IE can be a cell group configuration (CellGroupConfig) IE.

5. After receiving the RRC reconfiguration message, the terminal device sends an RRC reconfiguration completion message to the base station. The RRC reconfiguration completion message is used to confirm the RRC reconfiguration process sent by the base station in step 4;

6. The terminal device performs L1 measurement based on the L1 measurement configuration and sends an L1 measurement report. The L1 measurement configuration may be included in the RRC reconfiguration message in step 4.

7. The base station (e.g., source DU) determines to trigger L1/L2 triggered mobility based on the L1 measurement report sent by the terminal device;

8. The base station sends an L1/L2 triggered mobility cell change command to the terminal device. The cell change command can be carried on MAC CE or DCI. The cell change command indicates the target cell identifier of the terminal device switching, or indicates the target cell configuration identifier of the terminal device switching. The target cell is included in the above-mentioned candidate cells.

9. The terminal device accesses the target cell. The terminal device may perform synchronization with the base station (e.g., target DU) to which the target cell belongs. The synchronization process may be implemented through the RACH process, or through other processes (e.g., RACH-less);

10. If the configuration information of each candidate cell in step 4 is included in an RRC reconfiguration complete message, the terminal device sends an RRC reconfiguration complete message to the base station.

Solution 2: L1/L2 triggered mobility within CU and DU (intra-CU intra-DU).

Please refer to Figure 7, which is a schematic diagram of an interaction of intra-CU intra-DU L1/L2 triggered mobility provided by an embodiment of the present application. As shown in Figure 7, the process of intra-CU intra-DU L1/L2 triggered mobility includes:

3. The candidate DU sends a terminal device context establishment request confirmation message to the CU. If the candidate DU confirms that the terminal device can If the cell is connected, the CU is replied with a terminal device context establishment request confirmation message, which may include the configuration information of the candidate cell;

4. The base station (e.g., CU) sends an RRC reconfiguration message to the terminal device, which includes L1/L2 triggered mobility preconfiguration information. The L1/L2 triggered mobility preconfiguration information includes configuration information of one or more candidate cells. Optionally, the RRC reconfiguration message may also include configuration information of the source cell. The configuration information of each candidate cell may be sent in one of the following ways:

b) The configuration information of each candidate cell is included in an IE. That is, the RRC reconfiguration message sent by the base station to the terminal device in the fourth step includes one or more IEs, each including the configuration information of one or more candidate cells. For example, the IE may be a cell group configuration IE.

7. The base station (e.g., DU) determines to trigger L1/L2 triggered mobility based on the L1 measurement report sent by the terminal device;

8. The base station sends an L1/L2 triggered mobility cell change command to the terminal device. The cell change command can be carried on MAC CE or DCI. The cell change command indicates the target cell identifier of the terminal device switching, or indicates the target cell configuration identifier of the terminal device switching. The target cell is included in the above-mentioned candidate cells;

9. The terminal device accesses the target cell. The terminal device may perform synchronization to the base station (e.g., DU). The synchronization process may be implemented through the RACH process, or through other processes (e.g., RACH-less);

(5)CPAC

CPAC refers to the CPA and/or CPC process. CPA and CPC are the addition and change of PSCell in DC scenario respectively. The main idea is that the network equipment (such as the main base station) configures multiple candidate PSCell cells, and each candidate PSCell cell configuration includes the configuration of the cell and the associated execution conditions. When the execution conditions associated with a candidate cell are met, the terminal device can perform the addition or change of the PSCell to the candidate cell.

The CPA process is to perform the PSCell addition process when the PSCell addition conditions are met. Taking the MR-DC scenario, as shown in Figure 8, the CPA triggered by the MN is as follows:

1. The MN sends a request to add a secondary station to the SN where the candidate cell is located;

2. The SN where the candidate cell is located sends a secondary station addition request confirmation to the MN;

3. The MN sends the CPA configuration to the terminal device via the RRC reconfiguration message, which includes the configuration information of the candidate cells from each SN and the related execution conditions;

4. After receiving the RRC reconfiguration message from the MN, the terminal device sends an RRC reconfiguration complete message to the MN. The terminal device uses other RRC configurations in the RRC reconfiguration message except the CPA;

4a. The terminal device starts to evaluate the execution conditions. If the execution conditions of a candidate cell are met, the terminal device uses the configuration of the candidate cell selected in the RRC reconfiguration message (ie, the candidate cell that meets the execution conditions) and sends an RRC reconfiguration completion message (including an SN reconfiguration completion message) to the MN;

5.MN informs SN to complete the reconfiguration process;

6. The terminal device accesses the target cell (the candidate cell selected above/the candidate cell that meets the execution conditions), for example, performs a RACH process;

7.MN sends SN Status Transfer to the target SN;

8.MN forwards data to the target SN

9～12. Execute the path conversion process.

The CPC process is to execute the PSCell change process when the PSCell change conditions are met. Take the CPC process triggered by the MN in the MR-DC scenario as an example, as shown in Figure 9:

3. The MN sends CPC configuration to the terminal device via RRC reconfiguration message, which includes configuration information of candidate cells from each SN and related execution conditions;

4. After receiving the RRC reconfiguration message from the MN, the terminal device sends an RRC reconfiguration complete message to the MN. The terminal device uses other RRC configurations in the RRC reconfiguration message except the CPC;

4a.MN informs SN that CPC has been triggered through Xn-U address indication;

5. The terminal device starts to evaluate the execution conditions. If the execution conditions of a candidate cell are met, the terminal device uses the configuration of the candidate cell selected in the RRC reconfiguration message (that is, the candidate cell that meets the execution conditions) and sends an RRC reconfiguration complete message (including an SN reconfiguration complete message) to the MN;

6.MN informs the source SN to stop data transmission with the terminal device;

7.MN informs the target SN to complete the reconfiguration process;

8. The terminal device accesses the target cell (the candidate cell selected above/the candidate cell that meets the execution conditions), for example, performs a RACH process;

9. The source SN sends an SN state transfer to the target SN via the MN;

10. The MN forwards data to the target SN.

11～17. Execute the path conversion process.

(6) Continuous L1/L2 Triggered Mobility

The main idea of consecutive (or subsequent) L1/L2 triggered mobility is that after executing L1/L2 triggered mobility once, the terminal device does not release the L1/L2 triggered mobility configuration information, but continues to maintain the L1/L2 triggered mobility configuration information. The base station (such as the service DU of the terminal device) can determine the L1/L2 triggered mobility cell change command based on the measurement report reported by the terminal device, and the terminal device uses the maintained L1/L2 triggered mobility configuration information to execute subsequent L1/L2 triggered mobility based on the target cell indicated by the cell change command. That is, L1/L2 triggered mobility can be executed multiple times in succession.

Continuous L1/L2 triggered mobility can also be called subsequent L1/L2 triggered mobility, etc. Taking the execution of two consecutive inter-DU L1/L2 triggered mobility as an example, the process is shown in Figure 10:

Step 0 to Step 10: The same as the process in FIG. 6 , the first L1/L2 triggered mobility process is performed for the terminal device.

11. After completing the first L1/L2 triggered mobility, the target DU can indicate the handover completion to the CU. The ACCESS SUCCESS message can indicate the identifier of the target cell to which the terminal device is switching;

12. The terminal device continues to perform L1 measurement and reports the L1 measurement result, and the measurement result is reported to the base station. For example, the terminal device reports the measurement result to the target DU after the terminal device performs the first L1/L2 triggered mobility. At this time, the target DU becomes the DU connected to the terminal device at this time;

13. The DU where the terminal device is located determines the triggering of L1/L2 triggered mobility based on the measurement report reported by the terminal device, and determines the target cell for this handover;

14. The DU where the terminal device is located sends an L1/L2 triggered mobility cell change command to the terminal device, which includes the terminal The target cell identifier or target cell configuration identifier of the handover of the terminal device. The target cell is also included in the previously configured candidate cells. For example, the target cell of this handover is the previous source cell, or another candidate cell belonging to the same DU as the previous source cell;

15. The terminal device accesses the target cell of this handover. The terminal device can perform synchronization to the target DU of this handover. The synchronization process can be implemented through the RACH process, or through other processes (such as RACH-less);

16. If the configuration information of each candidate cell in step 4 is included in an RRC reconfiguration complete message, the terminal device sends an RRC reconfiguration complete message to the target cell.

The above steps 11 to 16 can be repeated multiple times. The terminal device can release the L1/L2 triggered mobility configuration based on the instruction of the network device, or release the L1/L2 triggered mobility configuration by itself, for example, the number of handovers reaches a threshold, or the duration of receiving the configuration reaches a threshold.

(7) Continuous CPAC

In CPAC, after completing the RACH process with the target cell, the terminal device releases the CPA/CPC configuration. Therefore, the terminal device cannot use the CPAC configuration before the network is reconfigured or restarted. In order to reduce the latency and signaling overhead of SCG switching, subsequent CPAC or the selective activation of cell groups process allows CPAC to continue after SCG switching and before network reconfiguration.

Taking continuous CPC as an example, the scenario is shown in Figure 11:

1. The terminal device communicates with the MN and cell 3 under the SN (there may be other SCells), that is, cell 3 is the PSCell cell of the terminal device at this time;

2. At this time, the network configures the CPC configuration for the terminal device, where the candidate cells include cells {1, 2, ..., 9}. The CPC configuration may also include the configuration and execution conditions of each candidate cell;

3. When the terminal device detects that the execution condition of cell 5 is met, the terminal device changes the PSCell cell to cell 5. After completing the connection with cell 5, the terminal device does not release the CPC configuration, but continues to maintain the CPC configuration and execute the CPC process.

4. The terminal device can continue to evaluate other candidate cells. When other candidate cells meet the execution conditions, the terminal device should trigger the PSCell change process. For example, in Figure 11, the terminal device subsequently detects that cell 3 meets the execution conditions, so the terminal device switches the PSCell cell to cell 3.

Taking two consecutive CPCs as an example, the process can be shown in Figure 12:

Step 1 to Step 8: The same as the process shown in FIG9 , which is the process of executing CPC for the first time;

9. After the terminal device switches to the new SN, it continues to evaluate the candidate cells;

10. If the terminal device evaluates a candidate cell that meets the execution conditions, the terminal device sends an RRC reconfiguration completion message to the MN, which may indicate the target candidate cell selected by the terminal device;

11. The MN forwards the SN reconfiguration message to the SN to which the candidate cell belongs;

12. The terminal device performs synchronization with the selected candidate cell.

The above steps 9 to 12 can be repeated multiple times. The terminal device can release the CPAC configuration based on the instruction of the network device, or release the CPAC configuration by itself, for example, when the number of switching executions reaches a threshold, or the time length of receiving the configuration reaches a threshold.

In L1/L2 triggered mobility, if in step 4 (e.g., FIG. 6 or FIG. 7 ) the configuration of each candidate cell in the L1/L2 triggered mobility configuration information sent by the base station (e.g., CU) to the terminal device is not sent via an RRC reconfiguration message, then when the L1/L2 triggered mobility to the candidate cell is triggered, the terminal device cannot respond to the RRC reconfiguration completion message to the candidate cell. That is, in step 10, the terminal device will not send an RRC reconfiguration completion message to the target cell, resulting in The candidate cell is unable to obtain information in the RRC reconfiguration completion message, such as resources or measurement parameters of the terminal device, which may cause the terminal device to be improperly configured or unable to perform normal data transmission after accessing the candidate cell.

For example, if the candidate cell cannot obtain the uplink DC parameters in Table 1, the candidate cell cannot avoid the uplink zero frequency point when providing configuration for the terminal device. If the terminal device sends data at this frequency point, data loss may occur. For another example, if the candidate cell cannot obtain the indication of whether a measurement gap is required in Table 1, the candidate cell cannot determine whether to configure a measurement gap for the terminal device when providing configuration for the terminal device, which affects the scheduling of the terminal device and thus affects data transmission. If other function information elements are subsequently introduced in the RRC reconfiguration completion message, the candidate cell will not be able to obtain this information, resulting in other impacts.

In order to solve the above problems, an embodiment of the present application provides a switching method, which is used for the candidate cell in the switching scenario to better obtain the information in the RRC reconfiguration completion message sent by the terminal device, so as to facilitate the normal configuration and data transmission of the terminal device after accessing the candidate cell.

FIG13 is a schematic diagram of an example of a communication method provided in an embodiment of the present application. The method can be performed by a terminal device and a network device, or can also be performed by a chip in a terminal device and a chip in a network device. It should be understood that FIG13 shows the steps or operations of the communication method, but these steps or operations are only examples, and the embodiment of the present application can also perform other operations or variations of the operations in FIG13, or reasonable exchanges between steps.

S1310, the terminal device receives the first message.

The first message carries first information or indicates first information, and the first information includes configuration information of M candidate cells, where M is a positive integer greater than 1.

Correspondingly, the network device sends a first message. The network device may be a base station or a CU.

Optionally, the first message is an RRC reconfiguration message, such as the RRC reconfiguration message in step 4 of FIG. 6 , FIG. 7 , or FIG. 10 .

In one example, the first information includes configuration information of M candidate cells, and the configuration information of the M candidate cells is respectively included in M RRC reconfiguration messages, and the M RRC reconfiguration messages are included in the first message. That is, the configuration information of each candidate cell is included in one RRC reconfiguration message, and the first information includes the M RRC reconfiguration messages.

In another example, the first information includes configuration information of M candidate cells, and the configuration information of the M candidate cells is respectively included in M IEs (e.g., CellGroupConfig IE), and the M IEs are included in the first message. That is, the configuration information of each candidate cell is included in one IE, and the first information includes the M IEs.

S1320, the terminal device sends a second message.

The second message carries M second information, and the M second information corresponds to the configuration information of the M candidate cells.

Accordingly, the network device receives the second message.

For example, the second message sent by the terminal device to the network device includes three second information, and the three second information correspond to the configuration information of the three candidate cells one by one. For example, the first second information corresponds to candidate cell 1, the second second information corresponds to candidate cell 2, and the third second information corresponds to candidate cell 3.

Optionally, the second message is an RRC reconfiguration complete message, such as the RRC reconfiguration complete message in step 5 of FIG. 6 , FIG. 7 , or FIG. 10 .

The second information corresponds to the configuration information of the candidate cell, which can be understood as the terminal device setting the content or value of the second information according to the configuration information of the candidate cell after receiving the configuration information of the candidate cell. The M second information corresponds to the configuration information of each of the M candidate cells, which can be understood as the terminal device setting the content or value of each second information according to the configuration information of each candidate cell, thereby determining the content of the M second information and including it in the second message. Optionally, the second information corresponding to the configuration information of the candidate cell can also be understood as the second information corresponding to the candidate cell.

Optionally, the second information includes one or more of the following information:

Uplink DC parameters, such as uplinkTxDirectCurrentList or uplinkTxDirectCurrentTwoCarrierList or uplinkTxDirectCurrentMoreCarrierList;

Conditional primary and secondary cells PSCell add or change related parameters, such as selectedCondRRCReconfig in Table 1;

Measurement report available indication, such as ue-MeasurementsAvailable in Table 1;

The measurement gap requirement indication, such as needForGapsConfigNR or needForGapNCSG-InfoNR or needForGapNCSG-InfoEUTRA in Table 1.

In the present application, the measurement gap may also be understood as a measurement interval.

It can be understood that the second information is the information included in the RRC reconfiguration complete message.

For example, the terminal device determines whether to include the uplink DC parameters in the second information corresponding to the candidate cell according to the report uplink DC indication included in the candidate cell configuration (e.g., reportUplinkTxDirectCurrent or reportUplinkTxDirectCurrentTwoCarrier or reportUplinkTxDirectCurrentMoreCarrier). For another example, the terminal device determines whether to include the measurement report available indication in the second information corresponding to the candidate cell according to whether it has recorded available measurements and the recorded measurement report configuration (e.g., VarLogMeasReport) in the candidate cell configuration. For another example, the terminal device determines whether to include the measurement gap requirement indication in the second information corresponding to the candidate cell according to the required gap configuration (e.g., needForGapsConfigNR or needForGapNCSG-ConfigNR or needForGapNCSG-ConfigEUTRA, etc.) in the candidate cell configuration.

In one implementation, the M second information are respectively included in M IEs, and each IE includes one or more of the above information, that is, each IE includes the second information of each candidate cell.

In another implementation, the second message includes RRC reconfiguration complete messages of M candidate cells, and the RRC reconfiguration complete messages of the M candidate cells carry M second information. That is, the second information of each candidate cell is included in one RRC reconfiguration complete message, and the M reconfiguration complete messages are included in the second message.

In an optional implementation, the RRC reconfiguration completion message of the M candidate cells does not include the RRC processing identifier, i.e., the rrc-TransactionIdentifier in Table 1. In this implementation, the configuration information of the M candidate cells included in the first information sent by the terminal device to the network device is included in M IEs (e.g., CellGroupConfig IE), rather than in M RRC reconfiguration messages. The RRC reconfiguration completion message of the M candidate cells is not used to respond to the M RRC reconfiguration messages, so there is no need to include the RRC processing identifier to identify the RRC reconfiguration process. In this implementation, by not including the RRC processing identifier in the M RRC reconfiguration completion messages, the problem of the terminal device being unable to set the value of the RRC processing identifier is avoided, and the problem of the network device being unable to determine the corresponding RRC process or the corresponding erroneous RRC processing process after receiving the RRC processing identifier is also avoided.

In an optional implementation, the second information is associated with or includes indication information, and the indication information is used to indicate the candidate cell or the configuration information of the candidate cell corresponding to the second information. Through the indication information, the second information sent by the terminal device to the network device can be associated with the configuration information of the candidate cell sent by the network device to the terminal device. When the configuration information of each candidate cell includes an RRC reconfiguration message and the second information is included in the RRC reconfiguration completion message, it can rely on the RRC processing identifier contained therein to correspond to the RRC reconfiguration completion message, but considering that the value of the RRC processing identifier is limited, occupying too many RRC processing identifiers may lead to restrictions on the RRC process between the terminal device and the network device. The indication information in this implementation solves this restriction problem.

The terminal device includes the second information of M candidate cells in the second message and sends it to the network device, and sends the information in the RRC reconfiguration completion message of the M candidate cells to the candidate cells, thereby solving the problem that the candidate cells cannot obtain the information in the RRC reconfiguration completion message, and avoiding the problem that the candidate cells cannot correctly configure the terminal device and the terminal device cannot transmit data normally.

S1330, the terminal device accesses the first cell.

Among them, the first cell belongs to M candidate cells.

Correspondingly, when the terminal device accesses the first cell, the network device to which the first cell belongs performs an access process with the terminal device. See step 9 in Figure 6 or Figure 7 or step 9 and step 15 in Figure 10. Optionally, as shown in Figure 13, the network device to which the first cell belongs is the network device that sends the first message.

Optionally, before accessing the first cell, the terminal device receives first indication information. The first indication information indicates that the terminal device accesses the first cell. Accordingly, the network device sends the first indication information. The first indication information can be carried in L1/L2 signaling, such as carried in MAC CE or DCI. Optionally, the first indication information is carried in the L1/L2 triggered mobility cell change command, see step 8 in Figure 6 or Figure 7 or steps 8 and 14 in Figure 10. The target cell for indicating the cell change in the first indication information is the first cell. After receiving the first indication information, the terminal device performs an access process to the first cell according to the content of the first indication information, such as through a RACH process or other processes (such as RACH-less).

Optionally, before receiving the first indication information, the terminal device may perform L1 measurement and send a measurement report to the network device, see step 6 in FIG. 6 or FIG. 7 or steps 6 and 12 in FIG. 10 .

Optionally, the network device sends second information corresponding to the first cell to the DU to which the first cell belongs, for example, sending part of the information in the second information. Optionally, the network device can be understood as a CU, or the network device includes the DU to which the first cell belongs, for example, the network device is a base station. It can be understood that the network device can submit corresponding second information to the DUs to which the M candidate cells belong when receiving the second information of the M candidate cells. The second information includes parameters required for DU configuration or required to be used by the DU, so the DU needs to obtain the second information before or when the terminal device accesses.

For example, as shown in FIG. 14 , the above solution is illustrated by taking L1/L2 triggered mobility between DUs within a CU as an example. Other scenarios of L1/L2 triggered mobility may refer to this embodiment and will not be described in detail.

In step 4 of Figure 14, the terminal device receives an RRC reconfiguration message from a base station (e.g., CU), and the reconfiguration complete message includes L1/L2 triggered mobility configuration information of one or more candidate cells. The L1/L2 triggered mobility configuration information of each candidate cell can be included in an IE (e.g., CellGroupConfig) or in an RRC reconfiguration message.

In step 5 of FIG. 14 , the terminal device sends an RRC reconfiguration complete message, wherein the reconfiguration complete message includes one of the following:

a) One or more RRC reconfiguration completion messages corresponding to one or more candidate cells. For example, the RRC reconfiguration completion message sent by the terminal device to the network device in step 5 includes a list of RRC reconfiguration completion messages of the candidate cells. Optionally, the RRC reconfiguration completion message corresponding to each candidate cell does not include an RRC processing identifier. Optionally, the RRC reconfiguration completion message corresponding to each candidate cell is associated with indication information, and the indication information is used to indicate the candidate cell or the configuration of the candidate cell corresponding to the RRC reconfiguration completion message, for example, the indication information is a candidate cell configuration identifier.

b) One or more information lists corresponding to one or more candidate cells. For example, the RRC reconfiguration completion message sent by the terminal device to the network device in step 5 contains an information list related to each candidate cell. The information list related to each candidate cell includes one or more of the uplink DC parameters, CPAC related parameters, whether the measurement report is available, whether the gap measurement is required, and other information. That is, the information originally contained in the RRC reconfiguration completion message (for example, the RRC reconfiguration completion message in step 10 of Figure 14). Optionally, the information list corresponding to each candidate cell is associated with indication information, and the indication information is used to indicate the candidate cell or the configuration of the candidate cell corresponding to the information list, for example, the indication information is a candidate cell configuration identifier.

After receiving the relevant information of each candidate cell, the base station (such as CU) stores the information. The CU can deliver the received relevant information of each candidate cell to the corresponding DU. Alternatively, when the terminal device is triggered to switch to a candidate cell, the CU uses the information of the candidate cell or sends relevant information to the DU to which the candidate cell belongs for use by the DU.

In the subsequent L1/L2 triggered mobility process, the terminal device no longer sends an RRC reconfiguration completion message to the base station.

In the above solution, the terminal device responds to the RRC reconfiguration message containing the L1/L2 triggered mobility configuration information. The RRC reconfiguration completion message includes information about multiple candidate cells. The terminal device determines the information about multiple candidate cells based on the configuration information of the candidate cells, and includes the information about the multiple candidate cells in the second message sent to the network device, which is used for the candidate cells to better configure the terminal device in the future, ensuring that the terminal device can be provided with better configuration information after accessing the candidate cell, thereby improving communication efficiency. The information about the multiple candidate cells includes the information originally included in the RRC reconfiguration completion message for multiple candidate cells. The terminal device solves the problem that the candidate cell cannot obtain the RRC reconfiguration completion message by providing the CU with relevant information about each candidate cell in advance, ensuring that the candidate cell can correctly configure the terminal device after the terminal device is switched, and ensuring normal communication. It also avoids the transmission of RRC messages during the L1/L2 triggered mobility process, avoids the delay of inter-layer interaction and RRC processing, and reduces the delay and interruption time of the L1/L2 triggered mobility process. In the scenario of continuous switching, the terminal device feeds back the required information of the candidate cell in the RRC reconfiguration completion message in reply to the RRC reconfiguration message that triggers the L1/L2 mobility configuration information. In this way, the terminal device does not need to send repeated information when accessing the same candidate cell subsequently, reducing redundant information transmission and saving air interface resources.

FIG15 is a schematic diagram of an example of a communication method provided in an embodiment of the present application. The method can be performed by a terminal device and a network device, or can also be performed by a chip in a terminal device and a chip in a network device. It should be understood that FIG15 shows the steps or operations of the communication method, but these steps or operations are only examples, and the embodiment of the present application can also perform other operations or variations of the operations in FIG15, or reasonable exchanges between steps.

S1510, the terminal device receives the third message.

The third message includes the third information or the third message indicates the third information, and the third information includes configuration information of N candidate cells and N configuration identifiers, and the N configuration identifiers are used to identify the configuration information of the N candidate cells, and N is a positive integer. The configuration information of the candidate cells is associated with the configuration identifier, and the configuration information of the N candidate cells is associated with the N configuration identifiers respectively. The configuration identifier can be a positive integer that increases sequentially starting from 1, for example, the configuration identifier can be 1, 2, 3, and so on.

Correspondingly, the network device sends a third message.

N configuration identifiers are used to identify the configuration information of N candidate cells, and it can be understood that the configuration information of each candidate cell is associated with a configuration identifier. For example, the third message sent by the network device to the terminal device includes the configuration information of 2 candidate cells and 2 configuration identifiers, the configuration identifier of candidate cell 1 is 1, and the configuration identifier of candidate cell 2 is 2. Optionally, the configuration identifier here is different from the RRC processing identifier.

Optionally, the third message is an RRC reconfiguration message.

Optionally, the configuration information of N candidate cells and N configuration identifiers are included in N IEs. That is, the configuration information of each candidate cell and the associated configuration identifier are included in one IE, and the configuration information of N candidate cells and the associated N configuration identifiers are included in the third message.

S1520, the terminal device receives the second indication information.

The second indication information is used to instruct the terminal device to access a second cell, which belongs to N candidate cells.

Correspondingly, the network device sends second indication information.

Optionally, the second indication information is carried in L1/L2 signaling, such as in MAC CE or DCI. Optionally, the second indication information is carried in an L1/L2 triggered mobility cell change command, see step 8 in FIG. 6 or FIG. 7 or step 8 and step 14 in FIG. 10. The target cell for indicating the cell change in the second indication information is the second cell. After receiving the second indication information, the terminal device performs an access process to the second cell according to the content of the second indication information, such as through a RACH process or other processes (such as RACH-less).

Optionally, before receiving the second indication information, the terminal device may perform L1 measurement and send a measurement report to the network device, see step 6 in FIG. 6 or FIG. 7 or steps 6 and 12 in FIG. 10 .

S1530, the terminal device sends a fourth message.

The fourth message includes a first identifier, and the first identifier is used to indicate the configuration information of the second cell. Optionally, the first identifier may be a configuration identifier associated with the configuration information of the second cell. That is, the first identifier is used to indicate the configuration identifier associated with the second cell or the target cell.

Optionally, the first identifier is related to the order of the configuration information of the candidate cells in the third information. It can be understood that the first identifier in the fourth message is used to indicate the order of the configuration information of the second cell. That is, the first identifier indicates the order of the configuration information of the second cell in all the candidate cell configuration information. For example, if the configuration information of the second cell is the second in the order of all the candidate cell configuration information, then the first identifier can be indicated as 2. Optionally, the third information does not include the configuration identifier at this time.

Correspondingly, the network device receives the fourth message. Optionally, the network device here may be different from the network device that sends the second indication information. For example, the network device that sends the second indication information may be a base station to which the source DU or source cell belongs, and the network device that receives the fourth message may be a base station or CU to which the target DU or target cell belongs.

Optionally, the network device receiving the fourth message and the network device sending the second indication information may be the same network device. For example, the source cell and the target cell of the terminal device belong to the same CU, and the network device to which the source cell belongs may be the same network device as the network device to which the target cell belongs.

Optionally, the fourth message is an RRC reconfiguration completion message.

Optionally, the RRC reconfiguration complete message does not include the RRC processing identifier. Since the configuration of the candidate cell is included in the IE and sent to the terminal device, that is, the candidate cell does not submit an RRC reconfiguration message to the terminal device, if the candidate cell receives an RRC reconfiguration complete message with an RRC processing identifier, the corresponding RRC reconfiguration process cannot be determined, resulting in network configuration confusion. Therefore, the RRC reconfiguration complete message may not carry the RRC processing identifier.

For example, as shown in FIG. 16 , the above solution is illustrated by taking L1/L2 triggered mobility between DUs within a CU as an example. Other scenarios of L1/L2 triggered mobility may refer to this embodiment and will not be described in detail.

In step 4 of Figure 16, the terminal device receives an RRC reconfiguration message from a base station (e.g., CU), which includes L1/L2 triggered mobility configuration information of one or more candidate cells. The triggered mobility configuration information for each candidate cell can be included in an IE (e.g., CellGroupConfig) and is associated with a configuration identifier for identifying the configuration.

In step 5 of FIG. 16 , the terminal device sends an RRC reconfiguration completion message to the CU or the base station;

Steps 6 to 9: are the same as FIG. 6 or FIG. 7 or FIG. 10, and are the first execution of the L1/L2 triggered mobility process;

In step 10, the terminal device sends an RRC reconfiguration complete message to the base station, wherein the message includes a configuration identifier associated with the candidate cell (or target cell) after the handover. Optionally, the RRC reconfiguration complete message does not include an RRC processing identifier;

Steps 11 to 15: are the same as FIG. 10 , and are the second execution of the L1/L2 triggered mobility process;

In step 16, the terminal device sends an RRC reconfiguration completion message to the base station, wherein the message includes a configuration identifier associated with the candidate cell after the switch. Optionally, the RRC reconfiguration completion message does not include an RRC processing identifier;

After receiving the RRC reconfiguration completion message, the CU may associate the content in the message with the candidate cell after the handover. The CU determines the configuration information to be used subsequently based on the received configuration identifier or the first identifier.

The above scheme associates the RRC reconfiguration completion message with the IE containing the candidate cell preconfiguration. By associating the RRC reconfiguration completion message with the candidate cell preconfiguration, the candidate cell after switching can obtain the candidate cell or candidate cell configuration corresponding to the RRC reconfiguration completion message. On the one hand, it solves the problem that the candidate cell cannot obtain the RRC reconfiguration completion message due to the absence of the RRC reconfiguration message. On the other hand, it also associates the information sent by the terminal device with the target cell configuration, ensuring that the candidate cell can correctly configure the terminal device after the terminal device is switched, ensuring normal communication. Compared with using the RRC processing identifier for association, the first identifier can have more values, thus avoiding the problem of limited network configuration caused by occupying more RRC processing identifiers.

During the L1/L2 triggered mobility process, if the terminal device accesses the same candidate cell multiple times, the content of the RRC reconfiguration completion message that the terminal device replies to the candidate cell is the same. For example, if this is not the first time that the terminal device accesses the target cell, the RRC reconfiguration completion message sent by the terminal device to the target cell in step 10 of Figure 6 is the same as the content sent when it first accesses the target cell. In this way, the terminal device sends the same content multiple times, which adds additional signaling overhead. In addition, the goal of L1/L2 triggered mobility is to reduce switching delay and terminal time. Sending RRC messages multiple times during the L1/L2 triggered mobility process will increase the delay of inter-layer interaction and RRC processing delay, which conflicts with the purpose of L1/L2 triggered mobility to reduce delay.

In the CPAC process, if the terminal device accesses the same candidate PSCell multiple times, the content of the SN reconfiguration completion message that the terminal device replies to the candidate cell is the same. For example, in step 5 of Figure 9 of the CPC process, if the terminal device is not accessing the candidate cell under the target SN for the first time, the RRC reconfiguration completion message of the target SN contained in the RRC reconfiguration completion message sent by the terminal device to the MN is the same as the RRC reconfiguration completion message of the target SN sent when accessing the candidate cell under the target SN for the first time. In this way, the terminal device sends the same content multiple times, which increases additional signaling overhead.

In order to solve the above problems, an embodiment of the present application provides a switching method for sending RRC messages during the switching process when entering a candidate cell for a non-first time in a switching scenario, thereby avoiding the problem of signaling overhead caused by information redundancy and reducing the consumption of air interface resources.

FIG17 is a schematic diagram of an example of a communication method provided in an embodiment of the present application. The method can be performed by a terminal device and a network device, or can also be performed by a chip in a terminal device and a chip in a network device. It should be understood that FIG17 shows the steps or operations of the communication method, but these steps or operations are only examples, and the embodiment of the present application can also perform other operations or variations of the operations in FIG17, or reasonable exchanges between steps.

S1710, the terminal device receives the fifth message.

The fifth message includes configuration information of L candidate cells, where L is a positive integer.

Correspondingly, the first network device sends a fifth message to the terminal device.

Optionally, the fifth message may be an RRC reconfiguration message. The L candidate cells may be candidate cells for L1/L2 triggered mobility, or the L candidate cells may be candidate PSCells for CPAC.

S1720, the terminal device accesses the third cell.

Among them, the third cell belongs to L candidate cells.

Correspondingly, when the terminal device accesses the third cell, the network device to which the third cell belongs performs an access process with the terminal device. See step 9 in FIG. 6 or FIG. 7 , or step 6 in FIG. 8 , or step 8 in FIG. 9 , or step 9 and step 15 in FIG. 10 , or step 8 and step 12 in FIG. 12 .

Optionally, the network device to which the third cell belongs may be the first network device. For example, as shown in FIG17 , the terminal device may initiate access to the first network device.

Optionally, before the terminal device accesses the third cell, it is evaluated that the execution condition of the third cell is satisfied, and the terminal device accesses the third cell. Optionally, the execution condition of evaluating the third cell here is satisfied, and reference can be made to the execution condition in the CPAC process. For example, the execution condition in step 5 of Figure 9 of the CPC process. In this way, the L candidate cells received by the terminal device are the L candidate PSCells of CPAC. After receiving the CPAC configuration, the terminal device evaluates the execution condition associated with the candidate cell.

Optionally, before the terminal device accesses the third cell, it receives third indication information, and the third indication information indicates that the terminal device accesses the third cell. Accordingly, the first network device sends the third indication information. Optionally, the third indication information is carried in L1/L2 signaling, such as carried in MAC CE or DCI. Optionally, the third indication information is carried in L1/L2 triggering In the mobility cell change command, please refer to step 8 in Figure 6 or Figure 7 or step 8 and step 14 in Figure 10. The target cell for indicating the cell change in the third indication information is the third cell. After receiving the third indication information, the terminal device performs an access process to the third cell according to the content of the third indication information, such as through a RACH process or other processes (such as RACH-less). In this way, the L candidate cells received by the terminal device are L candidate cells for L1/L2 triggered mobility.

S1730, the terminal device sends a first RRC reconfiguration completion message.

The first RRC reconfiguration complete message includes configuration information corresponding to the third cell. The first RRC reconfiguration complete message includes configuration information corresponding to the third cell, which can be understood as the terminal device setting the content or value in the first RRC reconfiguration complete message according to the configuration information of the third cell.

Correspondingly, the first network device receives a first RRC reconfiguration completion message.

Optionally, the first network device is a network device to which the third cell belongs, and in this case the terminal device can directly send the first RRC reconfiguration completion message to the network device to which the third cell belongs. For example, the first network device is a base station or a CU or a MN.

Optionally, the first network device is not the network device to which the third cell belongs. In this case, after receiving the first RRC reconfiguration completion message, the first network device also needs to send the first RRC reconfiguration completion message to the network device to which the third cell belongs. For example, the first network device is an MN, and the network device to which the third cell belongs is a candidate SN.

Optionally, the execution order of S1720 and S1730 may be to execute S1730 first and then S1720, or to execute S1720 first and then S1730, which is not limited in the embodiment of the present application.

Optionally, before sending the first RRC reconfiguration completion message, the terminal device determines whether it is accessing the third cell for the first time. In particular, if the terminal device accesses the third cell for the first time, the terminal device sends a first RRC reconfiguration completion message. Accordingly, the first network device receives the first RRC reconfiguration completion message. If it is not the first time for the terminal device to access the third cell, the terminal device does not send the first RRC reconfiguration completion message, or the terminal device sends a second RRC reconfiguration completion message. Accordingly, the first network device receives the second RRC reconfiguration completion message. That is, before executing step S1730, the terminal device needs to determine whether it is accessing the third cell for the first time or is about to access the third cell for the first time. The terminal device performs different actions according to different determined results.

Optionally, when one or more of the following situations occur, the terminal device needs to send a first RRC reconfiguration completion message when accessing a candidate cell for the first time:

After the network device configures the L1/L2 triggered mobility configuration, or instructs to update the L1/L2 triggered mobility configuration;

After the network device is configured with CPAC or the CPAC configuration is updated.

For example, whether the terminal device accesses the third cell for the first time can be understood as whether the terminal device accesses the third cell for the first time after receiving the fifth message. For example, if the terminal device accesses the third cell for the first time after receiving the fifth message, the terminal device sends a first RRC reconfiguration completion message. Correspondingly, the first network device or the network device to which the third cell belongs receives the first RRC reconfiguration completion message. If the terminal device does not access the third cell for the first time after receiving the fifth message, the terminal device does not send the first RRC reconfiguration completion message, or the terminal device sends the second RRC reconfiguration completion message. The fifth message may include the configuration information of the updated candidate cell. In this implementation, after the terminal device obtains the candidate cell configuration or the updated candidate cell configuration, for the same candidate cell configuration, if it is not the first time to access a candidate cell, the terminal device does not need to send repeated RRC reconfiguration completion message information, but does not send or sends a simplified RRC reconfiguration completion message, so as to save signaling overhead and air interface resources.

For another example, whether the terminal device accesses the third cell for the first time can be understood as whether the terminal device accesses the third cell for the first time during the operation of the first timer. For example, if the terminal device accesses the third cell for the first time during the operation of the first timer, the terminal device sends a first RRC reconfiguration completion message. Correspondingly, the first network device or the network device to which the third cell belongs receives the first RRC reconfiguration completion message. If the terminal device is not during the operation of the first timer, When accessing the third cell for the first time, the terminal device does not send the first RRC reconfiguration completion message, or the terminal device sends a second RRC reconfiguration completion message. Optionally, the terminal device starts the first timer when receiving the fifth message. Optionally, the terminal device stops or restarts the first timer after completing the switch. The duration of the first timer can be network-configured or predefined. In this implementation, the first timer is used to control the maintenance/preservation of the RRC reconfiguration completion information. During the operation of the timer, if it is not the first time to access a candidate cell, the terminal device does not need to send repeated RRC reconfiguration completion message information, but does not send or sends a simplified RRC reconfiguration completion message, so as to save signaling overhead and air interface resources. Optionally, if the timer times out, the terminal device sends a first RRC reconfiguration completion message each time it accesses a candidate cell.

Optionally, the second RRC reconfiguration completion message only includes the RRC processing identifier, or the second RRC reconfiguration completion message only includes the configuration identifier (refer to the configuration identifier in Figure 15), or the second RRC reconfiguration completion message only includes the RRC processing identifier and the configuration identifier, or the second RRC reconfiguration completion message is an empty message.

Optionally, the second RRC reconfiguration completion message does not include an SN reconfiguration completion message (for example, the scg-Response in Table 1), or the second RRC reconfiguration completion message includes an empty SN reconfiguration completion message, or the second RRC reconfiguration completion message includes an SN reconfiguration completion message that only includes an RRC processing identifier and/or a configuration identifier.

Optionally, the second RRC reconfiguration complete message does not include the first parameter. In a possible implementation, the first parameter is one or more parameters in Table 1. For example, the first parameter is whether a measurement gap (gap) indication parameter and/or an uplink DC parameter is required. For example, if the terminal device is not accessing the third cell for the first time after receiving the fifth message, the second RRC reconfiguration complete message sent by the terminal device to the first network device does not include the first parameter. For another example, if the terminal device is accessing the third cell for the first time after receiving the fifth message, the RRC reconfiguration complete message sent by the terminal device includes the first parameter. In this way, if certain parameters are reported to the network when the terminal device first accesses the cell, the terminal device does not need to report the parameter again when it accesses the cell again, making the terminal device more flexible in sending the RRC reconfiguration complete message and saving signaling overhead. As can be seen from Table 1, some parameters in the RRC reconfiguration complete message occupy more bits. If they are sent repeatedly, the signaling overhead consumed is large. This method is used for the first parameter in the RRC reconfiguration complete message, which reduces the repeated reporting of some parameters, reduces the signaling overhead, and saves transmission resources.

Optionally, if the fifth message is updated, the terminal device must resend the first parameter. For example, if the terminal device accesses the third cell for the first time after the fifth message is updated, the RRC reconfiguration completion message sent by the terminal device includes the first parameter. That is, if the configuration of the candidate cell is updated, the terminal device must also carry the first parameter in the RRC reconfiguration completion message after accessing the candidate cell for the first time.

The parameter information carried in the RRC reconfiguration complete message or the parameters that may not be repeatedly sent (e.g., the first parameter) may be configured or predefined by the network device. For example, in the case where the terminal device is not accessing the third cell for the first time, which parameters are carried in the RRC reconfiguration complete message, or which parameters are missing (e.g., no need to report repeatedly), or whether the parameters can be missing may be configured or predefined by the network device. Exemplarily, the network device may instruct the terminal device to always report the first parameter, or may not include the first parameter, in the case where the terminal device is not accessing the third cell for the first time.

For example, the network device may indicate in the configuration information of each candidate cell which parameters the terminal device carries in the RRC reconfiguration completion message. For example, in a case where the terminal device is not accessing the third cell for the first time, whether the uplink DC parameter is carried in the second RRC reconfiguration completion message. For another example, in a case where the terminal device is not accessing the third cell for the first time, whether the second RRC reconfiguration completion message carries a parameter indicating whether a measurement gap is required. For another example, the terminal device receives fourth indication information, and the fourth indication information indicates to the terminal device that the RRC reconfiguration completion message does not carry the first parameter when the terminal device is not accessing the third cell for the first time. Accordingly, the first network device sends the fourth indication information.

For another example, the missing parameter in the RRC reconfiguration complete message may also be predefined. For example, the terminal device sends an RRC reconfiguration complete message when switching to a candidate cell for a non-first time, but does not include the first parameter, such as the uplink DC information parameter.

For example, the network device instructs the terminal device not to report the first parameter when it is not the first time to switch to a candidate cell; or the network device instructs the terminal device to report the first parameter when it is not the first time to switch to a candidate cell. For another example, the terminal device receives the fifth indication information, and the fifth indication information indicates that after the terminal device receives the fifth message, when it does not access the third cell for the first time, the first parameter is not carried in the RRC reconfiguration completion message. The RRC reconfiguration completion message here can be the first RRC reconfiguration completion message or the second RRC reconfiguration completion message. Accordingly, the first network device sends the fifth indication information.

Optionally, if the first parameter changes, the terminal device needs to resend the first parameter. In one possible implementation, the change in the first parameter can be understood as the first parameter of the terminal device has changed from the first parameter reported last time. In another possible implementation, the change in the first parameter can be understood as the first parameter to be reported by the terminal device has changed compared with the first parameter reported last time. For example, after the first parameter changes, the first parameter must be included in the RRC reconfiguration completion message sent by the terminal device to the first network device. In other words, even if the terminal device is not accessing the third cell for the first time, once the first parameter is sent and changes, the terminal device must include the first parameter in the second RRC reconfiguration completion message reported, or the terminal device reports the first RRC reconfiguration completion message, or the terminal device includes the first parameter in the first RRC reconfiguration completion message reported. The change in the first parameter here may be triggered by a change in the configuration of the network device, or it may be triggered by the internal implementation of the terminal device.

Optionally, if the first parameter has not changed, the terminal device does not send an RRC reconfiguration completion message, or does not include the first parameter in the reported RRC reconfiguration completion message. For example, if the first parameter of the terminal device has not changed compared to the first parameter reported last time, the terminal device does not include the first parameter in the second RRC reconfiguration completion message reported to the first network device.

It can be understood that the terminal device and the network device store the content of the RRC reconfiguration completion message sent for a candidate cell, and determine whether to send the first parameter based on the stored content of the RRC reconfiguration completion message when subsequently accessing the candidate cell.

When the terminal device switches to a candidate cell for the first time, it sends an RRC reconfiguration completion message; the network device (such as CU) saves the content of the completion message. When the terminal device accesses the cell again (not the first time), the terminal device may not send an RRC reconfiguration completion message, or send an empty RRC reconfiguration completion message. If the network device receives a second RRC reconfiguration completion message containing an RRC processing identifier or a configuration identifier, the network identification can find the corresponding candidate cell according to the RRC processing identifier or the configuration identifier, thereby finding the information of the completion message corresponding to the stored candidate cell for subsequent use.

For example, in the L1/L2 triggered mobility scenario, if the terminal device switches to a certain L1/L2 triggered mobility candidate cell for the first time, an RRC reconfiguration completion message is sent to the network device to which the candidate cell belongs. If the terminal device accesses the candidate cell again (not for the first time), the terminal device does not send an RRC reconfiguration completion message, or sends a second RRC reconfiguration completion message.

For example, in a continuous CPAC scenario, if the terminal device switches to a candidate cell for the first time, an RRC reconfiguration completion message is sent to the MN (e.g., step 5 in FIG. 9 ), which includes a reconfiguration completion message sent to the SN to which the candidate PSCell belongs. The MN sends the reconfiguration completion message of the SN to the SN. The base station (e.g., MN or SN) saves the content of the completion message. If the terminal device accesses the candidate cell again (not for the first time), the RRC reconfiguration completion message sent by the terminal device to the MN (e.g., step 10 in FIG. 12 ) does not include an SN reconfiguration completion message, or includes an empty SN reconfiguration completion message, or includes an SN reconfiguration completion message that only includes an RRC processing identifier and/or a configuration identifier.

Optionally, in the following cases, the terminal device or the network device releases the stored content of the RRC reconfiguration complete message:

When the network device releases the L1/L2 triggered mobility process/configuration, or updates the L1/L2 triggered mobility configuration;

When L3 switching (such as inter-CU switching) is triggered;

When the network device releases the CPAC process/configuration, or updates the CPAC configuration;

When MN or PCell switching is triggered.

The above solution avoids the signaling overhead caused by information redundancy by reducing the sending of RRC messages in the subsequent switching process. The problem of L1/L2 triggered mobility is solved, and the consumption of air interface resources is reduced. For the scenario of L1/L2 triggered mobility, the delay of inter-layer interaction and RRC processing is also reduced, and the delay and interruption time of L1/L2 triggered mobility are reduced. Through the above solution, in the CPAC scenario, once the RACH process between the terminal device and the target SN is successful, the SN and the terminal device can use the stored message content for configuration and communication; avoid redundant information and save overhead.

FIG18 is a schematic diagram of an example of a communication method provided in an embodiment of the present application. The method may be performed by a terminal device and a network device, or may be performed by a chip in a terminal device and a chip in a network device. The communication method includes:

S1810, the terminal device receives the fifth message.

S1820, the terminal device accesses the third cell.

Among them, the third cell belongs to L candidate cells.

Optionally, the network device to which the third cell belongs may be the second network device. For example, as shown in FIG18 , the terminal device may initiate access to the second network device.

Optionally, before the terminal device accesses the third cell, it receives third indication information, and the third indication information instructs the terminal device to access the third cell. Accordingly, the first network device sends the third indication information. Optionally, the third indication information is carried in L1/L2 signaling, such as carried in MAC CE or DCI. Optionally, the third indication information is carried in the L1/L2 triggered mobility cell change command, as shown in step 8 in Figure 6 or Figure 7 or steps 8 and 14 in Figure 10. The target cell for indicating the cell change in the third indication information is the third cell. After the terminal device receives the third indication information, it performs an access process to the third cell according to the content of the third indication information, such as through a RACH process or other processes (such as RACH-less). In this way, the L candidate cells received by the terminal device are L candidate cells for L1/L2 triggered mobility.

S1830, the terminal device sends a first RRC reconfiguration completion message.

Correspondingly, the second network device receives the first RRC reconfiguration completion message. The second network device may be a target DU.

Optionally, the execution order of S1820 and S1830 may be to execute S1830 first and then S1820, or to execute S1820 first and then S1830.

Optionally, before sending the first RRC reconfiguration completion message, the terminal device determines whether to access the third cell for the first time.

If the terminal device accesses the third cell for the first time, the terminal device sends a first RRC reconfiguration completion message. The second network device receives the first RRC reconfiguration completion message. If the terminal device is not accessing the third cell for the first time, the terminal device does not send the first RRC reconfiguration completion message, or the terminal device sends the second RRC reconfiguration completion message. Accordingly, the second network device receives the second RRC reconfiguration completion message. That is, before executing step S1830, the terminal device needs to determine whether it is accessing the third cell for the first time or is about to access the third cell for the first time. The terminal device performs different actions according to different determined results.

Optionally, the second RRC reconfiguration complete message does not include the first parameter. For example, if the terminal device does not access the third cell for the first time after receiving the fifth message, the second RRC reconfiguration complete message sent by the terminal device to the second network device does not include the first parameter.

Optionally, if the first parameter has not changed, the terminal device does not send an RRC reconfiguration completion message, or does not include the first parameter in the reported RRC reconfiguration completion message. For example, if the first parameter of the terminal device has not changed compared to the first parameter reported last time, the terminal device does not include the first parameter in the second RRC reconfiguration completion message reported to the second network device.

Optionally, if the first parameter changes, the terminal device needs to resend the first parameter. For example, after the first parameter changes, the RRC reconfiguration completion message sent by the terminal device to the second network device includes the first parameter.

The detailed steps of this embodiment can refer to the relevant steps from S1710 to S1730, which will not be repeated here.

The above scheme avoids the signaling overhead caused by information redundancy and reduces the consumption of air interface resources by reducing the sending of RRC messages in the subsequent switching process. For the scenario of L1/L2 triggered mobility, it also reduces the delay of inter-layer interaction and RRC processing, and reduces the delay and interruption time of L1/L2 triggered mobility. Through the above scheme, in the CPAC scenario, once the RACH process between the terminal device and the target SN is successful, the SN and the terminal device can use the stored message content for configuration and communication, avoiding redundant information and saving overhead.

The various embodiments of the present invention may be used independently or in combination. The different steps in the various embodiments may also be used independently or in combination. If there are similar steps in different embodiments, their descriptions may be mutually quoted and referenced.

Corresponding to the above method, an embodiment of the present application provides a communication device. Figures 19 to 21 are schematic diagrams of the structures of possible communication devices provided by embodiments of the present application. These communication devices can be used to implement the functions of the terminal device or network device in the above method embodiments, and thus can also achieve the beneficial effects possessed by the above method embodiments. In an embodiment of the present application, the communication device can be a terminal device 101 as shown in Figure 1, or a network device 102 as shown in Figure 1, or a module (such as a chip) applied to a terminal device or a network device.

As shown in Fig. 19, the communication device 1900 includes a processing unit 1910 and a transceiver unit 1920. The communication device 1900 is used to implement the functions of the terminal device or network device in the method embodiments shown in Fig. 13 or Fig. 15 or Fig. 17 or Fig. 18 above.

When the communication device 1900 is used to implement the function of the terminal device in the method embodiment shown in Figure 13: the transceiver unit 1920 is used to receive a first message, the first message carries first information, the first information includes configuration information of M candidate cells, M is a positive integer greater than 1; the transceiver unit 1920 is also used to send a second message, the second message carries M second information, the M second information corresponds to the configuration information of the M candidate cells; the transceiver unit 1920 is also used to send an access request to a first cell, the first cell belongs to the M candidate cells.

Uplink DC parameters;

Measurement report available indication;

Measuring gap requirement indication.

In one possible design, the transceiver unit 1920 is specifically used to receive first indication information, where the first indication information indicates access to the first cell.

In one possible design, the processing unit 1910 is used to control or instruct the transceiver unit 1920 to receive, and is used to control or instruct the transceiver unit 1920 to send.

When the communication device 1900 is used to implement the function of the network device in the method embodiment shown in Figure 13: the transceiver unit 1920 is used to send a first message, the first message carries first information, the first information includes configuration information of M candidate cells, M is a positive integer greater than 1; the transceiver unit 1920 is also used to receive a second message, the second message carries M second information, and the M second information corresponds to the configuration information of the M candidate cells.

Uplink DC parameters;

Measurement report available indication;

Measuring gap requirement indication.

When the communication device 1900 is used to implement the function of the terminal device in the method embodiment shown in Figure 15: the transceiver unit 1920 is used to receive a third message, the third message includes third information, the third information includes configuration information of N candidate cells and N configuration identifiers, the N configuration identifiers are used to identify the configuration information of the N candidate cells, N is a positive integer; the transceiver unit 1920 is also used to receive second indication information, the second indication information is used to indicate access to a second cell, the second cell belongs to the N candidate cells; the transceiver unit 1920 is also used to send a fourth message, the fourth message includes a first identifier, wherein the first identifier is used to indicate the configuration information of the second cell.

When the communication device 1900 is used to implement the function of the network device in the method embodiment shown in FIG. 15 : the transceiver unit 1920, Used to send a third message, the third message includes third information, the third information includes configuration information of N candidate cells, N is a positive integer; the transceiver unit 1920 is also used to send second indication information, the second indication information is used to indicate that the terminal device accesses a second cell, and the second cell belongs to the N candidate cells; the transceiver unit 1920 is also used to receive a fourth message, the fourth message includes a first identifier; wherein the first identifier is used to indicate the configuration information of the second cell.

When the communication device 1900 is used to implement the function of the terminal device in the method embodiment shown in Figure 17: the transceiver unit 1920 is used to receive the fifth message, and the fifth message includes configuration information of L candidate cells, L is a positive integer; the processing unit 1910 is used to determine the first access to the third cell after receiving the fifth message; the transceiver unit 1920 is also used to send a first RRC reconfiguration completion message, and the first RRC reconfiguration completion message includes configuration information corresponding to the third cell, and the third cell belongs to the L candidate cells.

In a possible design, the processing unit 1910 is specifically used to evaluate whether the execution condition of the third cell is met; the transceiver unit 1920 is specifically used to send an access request to the third cell.

In one possible design, the transceiver unit 1920 is specifically used to receive third indication information, where the third indication information indicates access to the third cell.

In one possible design, the processing unit 1910 is specifically used to determine that it is not the first time to access the third cell after receiving the fifth message, and the transceiver unit 1920 is specifically used to send a second RRC reconfiguration completion message, and the second RRC reconfiguration completion message only includes an RRC processing identifier; or, the processing unit 1910 is used to determine that it is not the first time to access the third cell after receiving the fifth message, and instruct the transceiver unit 1920 not to send an RRC reconfiguration completion message.

In one possible design, the processing unit 1910 is specifically used to determine that it is not the first time to access the third cell after receiving the fifth message, and the transceiver unit 1920 is specifically used to send a second RRC reconfiguration completion message, and the second RRC reconfiguration completion message does not include the first parameter.

In one possible design, the processing unit 1910 is specifically used to determine that the first parameter has not changed, and the transceiver unit 1920 is specifically used to send a second RRC reconfiguration completion message, which does not include the first parameter; or, the processing unit 1910 is used to determine that the first parameter has not changed, and instruct the transceiver unit 1920 not to send an RRC reconfiguration completion message.

In one possible design, the first parameter is whether a measurement gap indication parameter or an uplink DC parameter is required.

In one possible design, the transceiver unit 1920 is specifically used to receive fourth indication information, where the fourth indication information indicates that the first parameter is not carried in the first RRC reconfiguration completion message or the second RRC reconfiguration completion message.

In one possible design, the processing unit 1910 is specifically used to control or instruct the transceiver unit 1920 to receive, and is specifically used to control or instruct the transceiver unit 1920 to send.

When the communication device 1900 is used to implement the function of the first network device in the method embodiment shown in Figure 17: the transceiver unit 1920 is used to send the fifth message, and the fifth message includes configuration information of L candidate cells, L is a positive integer; the processing unit 1910 is used to determine whether the terminal device accesses the third cell for the first time after sending the fifth message; the transceiver unit 1920 is also used to receive a first RRC reconfiguration completion message, and the first RRC reconfiguration completion message includes configuration information corresponding to the third cell, and the third cell belongs to the L candidate cells.

In one possible design, the transceiver unit 1920 is specifically used to send the third indication information. The third indication information instructs the terminal device to access the third cell.

In one possible design, the processing unit 1910 is specifically used to determine that this is not the first time that the terminal device accesses the third cell after receiving the fifth message; the transceiver unit 1920 is specifically used to receive a second RRC reconfiguration completion message, and the second RRC reconfiguration completion message only includes an RRC processing identifier; or, the processing unit 1910 is specifically used to determine that this is not the first time that the terminal device accesses the third cell after receiving the fifth message, and the processing unit 1910 instructs the transceiver unit 1920 not to receive the RRC reconfiguration completion message; or, the processing unit 1910 is specifically used to determine that this is not the first time that the terminal device accesses the third cell after receiving the fifth message, and the processing unit 1910 does not process the RRC reconfiguration completion message.

In one possible design, the processing unit 1910 is specifically used to determine that it is not the first time that the terminal device accesses the third cell after receiving the fifth message, and the transceiver unit 1920 is specifically used to receive a second RRC reconfiguration completion message, and the second RRC reconfiguration completion message does not include the first parameter.

In one possible design, the processing unit 1910 is specifically used to determine that the first parameter has not changed, and the transceiver unit 1920 is specifically used to receive a second RRC reconfiguration completion message, which does not include the first parameter; or, the processing unit 1910 is specifically used to determine that the first parameter has not changed, and the processing unit 1910 instructs the transceiver unit 1920 not to receive the RRC reconfiguration completion message; or, the processing unit 1910 is specifically used to determine that the first parameter has not changed, and the processing unit 1910 does not process the RRC reconfiguration completion message.

In one possible design, the transceiver unit 1920 is specifically used to send fourth indication information, and the fourth indication information indicates that the terminal device does not carry the first parameter in the first RRC reconfiguration completion message or the second RRC reconfiguration completion message.

When the communication device 1900 is used to implement the function of the terminal device in the method embodiment shown in Figure 18: the transceiver unit 1920 is used to receive the fifth message, and the fifth message includes configuration information of L candidate cells, L is a positive integer; the processing unit 1910 is used to determine the first access to the third cell after receiving the fifth message; the transceiver unit 1920 is also used to send a first RRC reconfiguration completion message, and the first RRC reconfiguration completion message includes configuration information corresponding to the third cell, and the third cell belongs to the L candidate cells.

When the communication device 1900 is used to implement the function of the first network device in the method embodiment shown in Figure 18: the transceiver unit 1920 is used to send a fifth message, and the fifth message includes configuration information of L candidate cells, where L is a positive integer.

In a possible design, the transceiver unit 1920 is specifically used to send the third indication information, and the third indication information indicates that the terminal device accesses the third cell.

When the communication device 1900 is used to implement the function of the second network device in the method embodiment shown in FIG. 18: the processing unit 1910 is used to determine that the terminal device accesses the third cell for the first time after sending the fifth message; the transceiver unit 1920 is used A first RRC reconfiguration complete message is received, where the first RRC reconfiguration complete message includes configuration information corresponding to the third cell, and the third cell belongs to the L candidate cells.

In one possible design, the processing unit 1910 is specifically used to determine that this is not the first time that the terminal device accesses the third cell after receiving the fifth message, and the transceiver unit 1920 is specifically used to receive a second RRC reconfiguration completion message, and the second RRC reconfiguration completion message does not include the first parameter.

The embodiment of the present application proposes a communication device 2000, as shown in Figure 20, which shows a schematic block diagram of another communication device of the embodiment of the present application. The communication device 2000 includes a processor 2010, the processor 2010 is coupled to at least one memory 2020, and the processor 2010 is used to read the computer program stored in the at least one memory 2020 to execute the method in any possible implementation of the embodiment of the present application.

The embodiment of the present application further proposes a communication device 2100. As shown in FIG21, the communication device 2100 includes a processor 2110 and an interface circuit 2120. The processor 2110 and the interface circuit 2120 are coupled to each other. It is understood that the interface circuit 2120 can be a transceiver or an input-output interface. Optionally, the communication device 2100 may also include a memory 2130 for storing instructions executed by the processor 2110 or storing input data required by the processor 2110 to execute instructions or storing data generated after the processor 2110 executes instructions.

When the communication device 2100 is used to implement the method shown in Figure 13 or Figure 15 or Figure 17 or Figure 18, the processor 2110 is used to implement the function of the above-mentioned processing unit 1910, and the interface circuit 2120 is used to implement the function of the above-mentioned transceiver unit 1920.

When the above communication device is a chip applied to a terminal device, the terminal device chip implements the functions of the terminal device in the above method embodiment. The terminal device chip receives information from other modules in the terminal device (such as a radio frequency module or an antenna), and the information is sent by the network device to the terminal device; or the terminal device chip sends information to other modules in the terminal device (such as a radio frequency module or an antenna), and the information is sent by the terminal device to the network device.

When the above communication device is a chip applied to a network device, the network device chip implements the function of the network device in the above method embodiment. The network device chip receives information from other modules in the network device (such as a radio frequency module or an antenna), and the information is sent by the terminal device to the network device; or the network device chip sends information to other modules in the network device (such as a radio frequency module or an antenna), and the information is sent by the network device to the terminal device.

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

The memory of the embodiment of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), and direct rambus RAM (DR RAM).

The embodiment of the present application provides a communication system 2200, including a terminal device 2210 and a network device 2220 in the communication method provided in the embodiment of the present application. As shown in FIG22 , a schematic block diagram of a communication system 2200 of the embodiment of the present application is shown.

The method steps in the embodiments of the present application can be implemented by hardware, or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, register, hard disk, mobile hard disk, CD-ROM or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and can write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC. In addition, the ASIC can be located in a network device or a terminal device. Of course, the processor and the storage medium can also be present in a network device or a terminal device as discrete components.

In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is executed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer program or instructions may be transmitted from one website site, computer, server or data center to another website site, computer, server or data center by wire or wireless means. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium. The computer readable storage medium may be a volatile or non-volatile storage medium, or may include both volatile and non-volatile storage media.

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

It can be understood that in the present application, "when", "if" and "if" all mean that the device will take corresponding actions under certain objective circumstances, and do not limit the time, nor do they require that the device must have a judgment action when it is implemented, nor do they mean that there are other limitations.

Those skilled in the art will appreciate that the first, second, and other various digital numbers involved in the present application are only for the convenience of description and are not intended to limit the scope of the embodiments of the present application. The specific values of the numbers (also referred to as indexes) in the present application, the specific values of the quantities, and the positions are only for illustrative purposes, are not the only form of representation, and are not intended to limit the scope of the embodiments of the present application. The first, second, and other various digital numbers involved in the present application are also only for the convenience of description and are not intended to limit the scope of the embodiments of the present application.

In addition, the term "and/or" in this application is only a description of the association relationship of associated objects, indicating that there may be three relationships. For example, A and/or B can represent three situations: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character "/" in this article generally indicates that the associated objects before and after are in an "or" relationship; the term "at least one" in this application can mean "one" and "two or more". For example, at least one of A, B and C can represent seven situations: A exists alone, B exists alone, C exists alone, A and B exist at the same time, A and C exist at the same time, C and B exist at the same time, and A, B and C exist at the same time.

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

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

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

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

Claims

A communication method, comprising:

receiving a first message, where the first message carries first information, and the first information includes configuration information of M candidate cells, where M is a positive integer greater than 1;

Sending a second message, where the second message carries M pieces of second information, and the M pieces of second information correspond to the configuration information of the M candidate cells;

Access a first cell, where the first cell belongs to the M candidate cells.
The method according to claim 1, characterized in that

The first message is a radio resource control RRC reconfiguration message, and the second message is an RRC reconfiguration complete message.
The method according to claim 1 or 2, characterized in that

The second information includes one or more of the following information:

Uplink DC parameters;

Conditional primary and secondary cells PSCell add or change related parameters;

Measurement report available indication;

Measuring gap requirement indication.
The method according to any one of claims 1 to 3 is characterized in that the second message includes an RRC reconfiguration completion message of M candidate cells, and the RRC reconfiguration completion message of the M candidate cells carries the M second information.
The method according to claim 4, characterized in that

The RRC reconfiguration completion message of the M candidate cells does not include an RRC processing identifier.
The method according to any one of claims 1 to 5, further comprising:

First indication information is received, where the first indication information indicates access to the first cell.
A communication method, comprising:

Sending a first message, where the first message carries first information, and the first information includes configuration information of M candidate cells, where M is a positive integer greater than 1;

A second message is received, where the second message carries M second information, and the M second information corresponds to the configuration information of the M candidate cells.
The method according to claim 7, characterized in that

The first message is an RRC reconfiguration message, and the second message is an RRC reconfiguration complete message.
The method according to claim 7 or 8, characterized in that

The second information includes one or more of the following information:

Uplink DC parameters;

Conditional primary and secondary cells PSCell add or change related parameters;

Measurement report available indication;

Measuring gap requirement indication.
The method according to any one of claims 7 to 9 is characterized in that the second message includes an RRC reconfiguration completion message of M candidate cells, and the RRC reconfiguration completion message of the M candidate cells carries the M second information.
The method according to claim 10, characterized in that

The RRC reconfiguration completion message of the M candidate cells does not include an RRC processing identifier.
A communication method, comprising:

receiving a third message, where the third message indicates third information, where the third information includes configuration information of N candidate cells and N configuration identifiers, where the N configuration identifiers are used to identify the configuration information of the N candidate cells, and N is a positive integer;

receiving second indication information, where the second indication information is used to indicate access to a second cell, where the second cell belongs to the N candidate cells;

A fourth message is sent, where the fourth message includes a first identifier; wherein the first identifier is used to indicate configuration information of the second cell.
The method according to claim 12, characterized in that

The third message is an RRC reconfiguration message, and the fourth message is an RRC reconfiguration complete message.
A communication method, comprising:

Sending a third message, where the third message includes third information, where the third information includes configuration information of N candidate cells, where N is a positive integer;

Sending second indication information, where the second indication information is used to instruct the terminal device to access a second cell, where the second cell belongs to the N candidate cells;

A fourth message is received, where the fourth message includes a first identifier; wherein the first identifier is used to indicate configuration information of the second cell.
The method according to claim 14, characterized in that

The third message is an RRC reconfiguration message, and the fourth message is an RRC reconfiguration complete message.
A communication method, comprising:

receiving a fifth message, where the fifth message includes configuration information of L candidate cells, where L is a positive integer;

If the third cell is accessed for the first time after receiving the fifth message, a first RRC reconfiguration complete message is sent, wherein the first RRC reconfiguration complete message includes configuration information corresponding to the third cell, and the third cell belongs to the L candidate cells.
The method according to claim 16 is characterized in that it also includes evaluating whether the execution condition of the third cell is met and accessing the third cell.
The method according to claim 16 is characterized in that it also includes receiving third indication information, wherein the third indication information indicates access to the third cell.
The method according to any one of claims 16 to 18, further comprising:

If it is not the first time to access the third cell after receiving the fifth message, a second RRC reconfiguration complete message is sent, and the second RRC reconfiguration complete message only includes the RRC processing identifier; or,

If it is not the first time to access the third cell after receiving the fifth message, the RRC reconfiguration complete message is not sent.
A communication method, characterized by comprising:

The first network device sends a fifth message to the terminal device, where the fifth message includes configuration information of L candidate cells, where L is a positive integer;

If the terminal device accesses the third cell for the first time after receiving the fifth message, the terminal device sends a first RRC reconfiguration completion message to the first network device, and the first RRC reconfiguration completion message includes configuration information corresponding to the third cell, and the third cell belongs to the L candidate cells.
The system according to claim 20, further comprising:

The first network device sends third indication information to the terminal device,

The third indication information instructs the terminal device to access the third cell.
The system according to claim 20 or 21, characterized in that it also includes:

The terminal device evaluates that the execution condition of the third cell is met and accesses the third cell.
The system according to any one of claims 20 to 22, further comprising:

If it is not the first time that the terminal device accesses the third cell after receiving the fifth message, the terminal device sends a second RRC reconfiguration completion message to the first network device, and the second RRC reconfiguration completion message only includes the RRC processing identifier; or,

If it is not the first time that the terminal device accesses the third cell after receiving the fifth message, the terminal device does not send an RRC reconfiguration completion message.
A communication method, comprising:

The first network device sends a fifth message to the terminal device, where the fifth message includes configuration information of L candidate cells, where L is a positive integer;

If the terminal device accesses the third cell for the first time after receiving the fifth message, the terminal device sends a first RRC reconfiguration completion message to the second network device, where the first RRC reconfiguration completion message includes configuration information corresponding to the third cell, and the third cell belongs to the L candidate cells;

The second network device is a network device to which the third cell belongs.
The system according to claim 24, further comprising:

The first network device sends third indication information to the terminal device,

The third indication information instructs the terminal device to access the third cell.
The method according to claim 24 or 25, characterized in that it also includes:

The terminal device evaluates that the execution condition of the third cell is met and accesses the third cell.
The method according to any one of claims 24 to 26, further comprising:

If it is not the first time that the terminal device accesses the third cell after receiving the fifth message, the terminal device sends a second RRC reconfiguration completion message to the second network device, and the second RRC reconfiguration completion message only includes the RRC processing identifier; or,

If it is not the first time that the terminal device accesses the third cell after receiving the fifth message, the terminal device does not send an RRC reconfiguration completion message.
A communication method, comprising:

receiving a fifth message, where the fifth message includes configuration information of L candidate cells, where L is a positive integer;

If it is not the first time to access the third cell after receiving the fifth message, a second RRC reconfiguration completion message is sent, and the second RRC reconfiguration completion message does not include the first parameter, the third cell belongs to the L candidate cells, and the first parameter is whether a measurement gap indication parameter or at least one of an uplink DC parameter is required.
The method according to claim 28, characterized in that, if the third cell is not accessed for the first time after the fifth message is received, sending a second RRC reconfiguration complete message comprises:

If it is not the first time to access the third cell after receiving the fifth message, and the first parameter has not changed, the second RRC reconfiguration completion message is sent.
The method according to any one of claims 28 or 29, characterized in that

Fourth indication information is received, where the fourth indication information is used to indicate that the first parameter is not carried in the second RRC reconfiguration complete message.
A communication method, characterized by comprising:

Sending a fifth message to the terminal device, where the fifth message includes configuration information of L candidate cells, where L is a positive integer;

If it is not the first time that the terminal device accesses the third cell after receiving the fifth message, it receives a second RRC reconfiguration completion message, the second RRC reconfiguration completion message does not include the first parameter, the third cell belongs to the L candidate cells, and the first parameter is whether a measurement gap indication parameter or at least one of an uplink DC parameter is required.
The method according to claim 31, characterized in that if the terminal device does not access the third cell for the first time after receiving the fifth message, receiving the second RRC reconfiguration completion message further comprises:

If it is not the first time that the terminal device accesses the third cell after receiving the fifth message, and the first parameter has not changed, a second RRC reconfiguration completion message is received.
The method according to any one of claims 31 or 32, characterized in that

Send fourth indication information, where the fourth indication information is used to instruct the terminal device not to carry the first parameter in the second RRC reconfiguration completion message.
A terminal device, characterized in that it comprises a processor, the processor is coupled to at least one memory, and the processor is used to read a computer program stored in the at least one memory to execute claims 1 to 6, or The method according to any one of claims 12 to 13, or 16 to 19, or 28 to 30, or the method according to any one of claims 7 to 11.
A network device, characterized in that it includes a processor, which is coupled to at least one memory, and the processor is used to read a computer program stored in the at least one memory to execute the method described in any one of claims 7 to 11, or 14 to 15, or 31 to 33.
A communication device, characterized in that it includes at least one processor and an interface circuit, wherein the interface circuit is used to provide input or output of instructions and/or data for the at least one processor, and when the at least one processor executes the above instructions, the device implements the method described in any one of claims 1-33.
A computer-readable storage medium comprising instructions, which, when executed on a computer, causes the computer to execute the method of any one of claims 1 to 6, or 12 to 13, or 16 to 19, or 28 to 30, or causes the computer to execute the method of any one of claims 7 to 11, or 14 to 15, or 20 to 23, or 24 to 27, or 31 to 33.
A computer program product comprising instructions which, when executed on a computer, causes the computer to perform the method as claimed in any one of claims 1 to 6, or 12 to 13, or 16 to 19, or 28 to 30, or causes the computer to perform the method as claimed in any one of claims 7 to 11, or 14 to 15, or 20 to 23, or 24 to 27, or 31 to 33.
A chip, characterized in that it includes a processor and a communication interface, wherein the processor is used to read instructions or computer programs to execute the method as described in any one of claims 1 to 6, or 12 to 13, or 16 to 19, or 28 to 30, or to enable the computer to execute the method as described in any one of claims 7 to 11, or 14 to 15, or 31 to 33.
A communication system, characterized in that it includes the terminal device as described in claim 34 and the network device as described in claim 35.