CN117715125A

CN117715125A - Switching method, communication device, and readable storage medium

Info

Publication number: CN117715125A
Application number: CN202211098371.9A
Authority: CN
Inventors: 毛颖超; 强鹂; 常俊仁; 李娇娇
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2022-09-08
Filing date: 2022-09-08
Publication date: 2024-03-15
Also published as: TW202412541A; WO2024051421A1

Abstract

The embodiment of the application relates to the technical field of communication, and provides a switching method, a communication device and a readable storage medium. The switching method comprises the following steps: the terminal equipment receives a first message from the network equipment; the first message comprises configuration information of M first candidate cells switched by the first message, wherein M is a positive integer; the terminal equipment receives a second message from the network equipment; the second message includes configuration information of a target cell of the second handover; the terminal equipment executes second switching according to the second message; the second switching is successfully completed, and the terminal equipment executes a first operation; the first operation includes reserving, releasing, or reconfiguring configuration information of the M first candidate cells. In the scene of simultaneously supporting the first handover and the second handover, the configuration information of the first candidate cell is reserved, released or reconfigured, so that the subsequent first handover is facilitated, and the handover success rate is improved.

Description

Switching method, communication device, and readable storage medium

Technical Field

The embodiment of the application relates to the technical field of communication, in particular to a switching method, a communication device and a readable storage medium.

Background

In a mobile communication system, a terminal device may move from the coverage of one cell to the coverage of another cell due to the movement of the terminal device. In order to ensure service continuity and communication quality of the terminal device, a Handover (HO) is required to be performed from the current serving cell to the target cell.

With the development of communication technology, the mobile communication technology has been developed from the second generation mobile communication technology (2G), through the third generation mobile communication technology (3G) and the fourth generation mobile communication technology (4G), to the fifth generation mobile communication technology (5G). Cell switching has a variety of switching modes. For example, the network device may configure the target cell for handover directly for the terminal device, or the network device may configure the candidate cell for handover for the terminal device.

A low-layer (L1/L2) based handover is a mobility procedure within the same Centralized Unit (CU), for example when the terminal device moves within an area, by which latency and interruption can be reduced, faster handover to the target cell. Whereas for radio resource control layer (radio resource control, RRC) based handover, the mobility procedure of the terminal device may be within the same CU or between different CUs, e.g. a terminal device on a high-speed moving high-speed rail is to perform a handover procedure between CUs. In order to better and more effectively perform mobility, the terminal device supports and configures both the lower layer-based handover and the RRC-based handover at the same time is a new and reasonable application scenario.

In this application scenario, the network device configures a plurality of candidate cells for the terminal device, and how to process the plurality of candidate cells, so as to improve the success rate of handover, which needs to be solved.

Disclosure of Invention

The application provides a handover method, a communication device and a readable storage medium, which improve the handover success rate in a scenario of simultaneously supporting a handover based on a lower layer and a handover based on RRC.

In a first aspect, the present application provides a handover method, where an execution body of the handover method may be a terminal device, or may be a chip applied in the terminal device. The following describes an example in which the execution subject is a terminal device. The switching method comprises the following steps: the terminal equipment receives a first message from the network equipment; the first message comprises configuration information of M first candidate cells switched by the first message, wherein M is a positive integer; the terminal equipment receives a second message from the network equipment; the second message includes configuration information of a target cell of the second handover; the terminal equipment executes second switching according to the second message; the second switching is successfully completed, and the terminal equipment executes a first operation; the first operation includes reserving, releasing, or reconfiguring configuration information of the M first candidate cells.

The method is suitable for a scene supporting the first switching and the second switching simultaneously. The terminal equipment receives configuration information of M first candidate cells configured by the network equipment and is used for first switching. When the terminal device executes the second handover and completes the second handover successfully, by reserving, releasing or reconfiguring the configuration information of the first candidate cell, the situation that the memory is occupied by invalid storage of the configuration of the first candidate cell is avoided, or signaling overhead is saved, the subsequent first handover is facilitated, and the handover success rate is improved.

In one possible design, the second message further includes indication information indicating that configuration information of all of the M first candidate cells or at least one of the M first candidate cells is reserved, released, or reconfigured; the terminal device performs a first operation comprising: and the terminal equipment reserves, releases or reconfigures configuration information of all or part of the first candidate cells in the M first candidate cells according to the indication information.

According to the mode, the terminal equipment reserves, releases or reconfigures the configuration information of all or part of the first candidate cells in the M first candidate cells according to the indication information indicated by the network equipment, and the implementation mode is simple. In addition, the network equipment determines how to process the configuration information of the first candidate cell, so that the accuracy of configuration is ensured, and the success rate of switching is further improved.

In one possible design, the indication information is a 1-bit indication information; or, the indication information is first bit map indication information.

In the mode, the indication information is 1-bit indication information, the signaling overhead is small, and the air interface resource is saved. The indication information is first bit mapping indication information, and the configuration information of the first candidate cell is processed for different objects in a bit mapping mode, so that the switching success rate is improved, and the flexibility of the indication information implementation is expanded.

In one possible design, the second handover is a conditional handover, the second message including configuration information of N second candidate cells for the conditional handover, N being a positive integer; and associating 1-bit indication information with any one of the N second candidate cells.

According to the mode, 1 bit indication information is associated with any one second candidate cell, and configuration information of the first candidate cell is processed according to different second candidate cells, so that the success rate of switching is improved, and the flexibility of indication information realization is expanded.

In one possible design, the second handover is a conditional handover, the second message including configuration information of N second candidate cells for the conditional handover, N being a positive integer; the indication information is first bit mapping indication information, the first bit mapping indication information indicates that S second candidate cells in the N second candidate cells are associated with 1 bit indication information, and S is a positive integer less than or equal to N.

According to the method, the configuration information of the first candidate cells is respectively processed for the different second candidate cells in a bit mapping mode, so that the success rate of switching is improved, and the flexibility of indication information realization is expanded.

In one possible design, the indication information includes a configuration identification of the at least one cell, the configuration identification being associated with configuration information of the at least one first candidate cell; or, the indication information is second bit map indication information.

By carrying the configuration identifier of the cell in the indication information in the mode, the configuration information of the first candidate cell is released or reserved for different first candidate cells, so that the success rate of switching is improved, and the flexibility of the indication information implementation is expanded. The indication information is second bit mapping indication information, and configuration information of the first candidate cells is released or reserved for different first candidate cells in a bit mapping mode, so that the success rate of switching is improved, and the flexibility of indication information implementation is expanded.

In one possible design, the indication information includes a PCI of at least one cell, the PCI of at least one cell being associated with configuration information of at least one first candidate cell.

In the above manner, the configuration identifier of the cell is PCI. By carrying PCI in the indication information, the configuration information of the first candidate cell is released or reserved for different first candidate cells, so that the success rate of switching is improved, and the flexibility of the indication information implementation is expanded.

In one possible design, the indication information is second bit map indication information, where the second bit map indication information indicates that K first candidate cells in the M first candidate cells are associated with 1 bit indication information, and K is a positive integer less than or equal to M.

According to the mode, the configuration information of the K first candidate cells is released or reserved for the associated K first candidate cells in a bit mapping mode, so that the success rate of switching is improved, and the flexibility of indication information implementation is expanded.

In one possible design, the second handover is a conditional handover, the second message including configuration information of N second candidate cells for the conditional handover, N being a positive integer; and associating the second bit mapping indication information with any one of the N second candidate cells.

In the mode, any one second candidate cell is associated with the second bit mapping indication information, the configuration information of the first candidate cell can be processed respectively for different second candidate cells, and for each second candidate cell, the configuration information of K first candidate cells can be released or reserved in a bit mapping mode through the second bit mapping indication information, so that the switching success rate is improved, and the flexibility of indication information realization is expanded.

In one possible design, the indication information includes reconfiguration information of the first candidate cell; the reconfiguration information is used to indicate at least one of the following: releasing configuration information of part of the first candidate cells in the M first candidate cells, adding configuration information of at least one candidate cell except the M first candidate cells, releasing configuration information of the M first candidate cells, reserving configuration information of the M first candidate cells or reconfiguring configuration information of at least one candidate cell in the M first candidate cells.

In the above manner, according to the reconfiguration information, for M first candidate cells that have been saved by the terminal device, the configuration information of all or part of the first candidate cells may be retained or released. And the configuration information of the new candidate cell can be added according to the reconfiguration information, so that the effect of reconfiguring the configuration of the first candidate cell is achieved, and the implementation mode is more flexible.

In one possible design, the terminal device performs a first operation including: the target cell of the second handover is a first candidate cell in the M first candidate cells, the terminal equipment reserves configuration information of the M first candidate cells, or the terminal equipment reserves configuration information of the first candidate cell related to the target cell of the second handover in the M first candidate cells; or, the target cell of the second handover is not the first candidate cell of the M first candidate cells, and the terminal device releases the configuration information of the M first candidate cells.

In the mode, the terminal equipment determines the mode of processing the configuration information of the M first candidate cells, the network side is not required to send the indication information, the air interface signaling overhead is saved, and the implementation mode is flexible.

In one possible design, the switching method further includes: the second handover fails, and the terminal device executes RRC reestablishment; the RRC reestablishes that the selected target cell is a first candidate cell in the M first candidate cells, and the terminal equipment executes first switching according to the configuration information of the first candidate cell associated with the target cell.

In the above manner, the UE fails to perform the second handover, and the original procedure is to perform RRC reestablishment. However, if the target cell of RRC re-establishment is the first candidate cell, access delay and interruption of service are reduced by preferentially performing the first handover.

In one possible design, the second handover is a conditional handover, the second message including configuration information of N second candidate cells for the conditional handover, N being a positive integer; the switching method further comprises the following steps: the second handover fails, and the terminal device executes RRC reestablishment; the RRC reestablishes the selected target cell as a second candidate cell in the N second candidate cells, and the terminal equipment executes conditional switching according to the second candidate cell.

In the above manner, the UE fails to perform the second handover, and the original procedure is to perform RRC reestablishment. However, if the target cell re-established by the RRC is the second candidate cell, the access delay and interruption of the service are reduced by preferentially performing the conditional handover.

In one possible design, the first message and the second message are the same.

By the mode, the interaction times of the message on the air interface are saved.

In one possible design, the second handover is successfully completed, and the terminal device performs a first operation, including: the terminal equipment executes the second switching, and the terminal equipment executes the first operation; or the terminal equipment sends a switching completion message, and the terminal equipment executes a first operation; or the terminal equipment completes the random access to the target cell of the second handover, and the terminal equipment executes the first operation.

In a second aspect, the present application provides a handover method, where the method may be executed by a network device or a chip applied in the network device. The following describes an example in which the execution subject is a network device. The switching method comprises the following steps: the network equipment sends a first message to the terminal equipment; the first message comprises configuration information of M first candidate cells switched by the first message, wherein M is a positive integer; the network equipment sends a second message to the terminal equipment; the second message includes configuration information of the target cell of the second handover and indication information indicating that configuration information of all of the M first candidate cells or at least one of the M first candidate cells is reserved, released or reconfigured.

The method is suitable for a scene supporting the first switching and the second switching simultaneously. The network device configures configuration information of M first candidate cells for the terminal device for a first handover. The network equipment determines how to process the configuration information of the first candidate cell, so that the accuracy of configuration is ensured, and the success rate of switching is further improved.

In one possible design, the second handover is a conditional handover, the second message including configuration information of N second candidate cells for the conditional handover, N being a positive integer; the indication information is first bit mapping indication information, the first bit mapping indication information is used for indicating that S second candidate cells in the N second candidate cells are associated with 1 bit indication information, and S is a positive integer less than or equal to N.

In one possible design, the indication information is second bit mapping indication information, where the second bit mapping indication information is used to indicate that K first candidate cells in the M first candidate cells are associated with 1 bit indication information, and K is a positive integer less than or equal to M.

In one possible design, the indication information includes reconfiguration information of the first candidate cell; the reconfiguration information is used to indicate at least one of the following: releasing the configuration information of part of the first candidate cells in the M first candidate cells, adding the configuration information of at least one first candidate cell in the M first candidate cells, releasing the configuration information of the M first candidate cells or reserving the configuration information of the M first candidate cells.

In a third aspect, a communication device is provided, and advantageous effects may be seen from the description of the first aspect, which is not repeated here. The communication device has the functionality to implement the actions in the method example of the first aspect described above. The functions may be implemented by hardware, or may be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions described above. In one possible design, the communication device includes: the receiving and transmitting module is used for receiving a first message from the network equipment, wherein the first message comprises configuration information of M first candidate cells of the first handover, and M is a positive integer; the transceiver module is further configured to receive a second message from the network device, where the second message includes configuration information of a target cell for the second handover; the processing module is used for executing second switching according to the second message; the second switching is successfully completed, and the first operation is executed; the first operation includes reserving, releasing, or reconfiguring configuration information of the M first candidate cells. These modules may perform the corresponding functions in the method examples of the first aspect, which are specifically referred to in the detailed description of the method examples and are not described herein.

In a fourth aspect, a communication device is provided, and advantageous effects may be seen from the description of the second aspect and are not repeated here. The communication device has the functionality to implement the behavior in the method example of the second aspect described above. The functions may be implemented by hardware, or may be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions described above. In one possible design, the communication device includes: the receiving and transmitting module is used for sending a first message to the terminal equipment, wherein the first message comprises configuration information of M first candidate cells switched first, and M is a positive integer; the transceiver module is further configured to send a second message to the terminal device, where the second message includes configuration information of the target cell of the second handover and indication information, and the indication information indicates to reserve, release, or reconfigure configuration information of all of the M first candidate cells or at least one of the M first candidate cells. These modules may perform the corresponding functions in the method examples of the second aspect, which are specifically referred to in the method examples and are not described herein.

In a fifth aspect, a communication device is provided, where the communication device may be a terminal device in an embodiment of the method described above, or a chip provided in the terminal device. The communication device comprises a communication interface and a processor, and optionally a memory. The memory is used for storing a computer program or instructions, and the processor is coupled with the memory and the communication interface, when the processor executes the computer program or instructions, the communication device executes the method executed by the terminal device in the method embodiment.

In a sixth aspect, a communication apparatus is provided, where the communication apparatus may be a network device in the above method embodiment, or a chip provided in the network device. The communication device comprises a communication interface and a processor, and optionally a memory. The memory is used for storing a computer program or instructions, and the processor is coupled with the memory and the communication interface, when the processor executes the computer program or instructions, the communication device executes the method executed by the network device in the method embodiment.

In a seventh aspect, there is provided a computer program product comprising: computer program code which, when executed, causes the method performed by the terminal device in the above aspects to be performed.

In an eighth aspect, there is provided a computer program product comprising: computer program code which, when executed, causes the method performed by the network device in the above aspects to be performed.

In a ninth aspect, the present application provides a chip system, where the chip system includes a processor, and the processor is configured to implement a function of a terminal device in the methods in the above aspects. In one possible design, the chip system further includes a memory for holding program instructions and/or data. The chip system can be composed of chips, and can also comprise chips and other discrete devices.

In a tenth aspect, the present application provides a chip system, where the chip system includes a processor, and the processor is configured to implement the functions of the network device in the methods of the above aspects. In one possible design, the chip system further includes a memory for holding program instructions and/or data. The chip system can be composed of chips, and can also comprise chips and other discrete devices.

In an eleventh aspect, the present application provides a computer readable storage medium storing a computer program which, when executed, implements the method performed by the terminal device in the above aspects.

In a twelfth aspect, the present application provides a computer readable storage medium storing a computer program which, when executed, implements the method performed by the network device in the above aspects.

In a thirteenth aspect, the present application provides a communication method, including: the network equipment sends a first message to the terminal equipment; the first message includes configuration information of M first candidate cells for the first handover, where M is a positive integer. The terminal device receives a first message from the network device. The network equipment sends a second message to the terminal equipment; the second message includes configuration information of the target cell of the second handover and indication information indicating that configuration information of all of the M first candidate cells or at least one of the M first candidate cells is reserved, released, or reconfigured. The terminal equipment receives a second message from the network equipment, and the terminal equipment executes the second switching according to the second message. The second switching is successfully completed, and the terminal equipment executes a first operation; the first operation includes reserving, releasing, or reconfiguring configuration information of the M first candidate cells.

In a fourteenth aspect, the present application provides a communication system, which includes a terminal device for implementing the functions of the terminal device in the method of the thirteenth aspect, and a network device for implementing the functions of the network device in the method of the thirteenth aspect.

Drawings

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

fig. 2 is a message flow diagram of L3 HO provided in an embodiment of the present application;

FIG. 3 is a message flow diagram of L3 CHO provided in accordance with an embodiment of the present application;

fig. 4 is a message flow diagram of a L1/L2 HO provided in an embodiment of the present application;

fig. 5 is a message flow diagram for supporting both L3 HO and L1/L2 HO provided by an embodiment of the present application;

FIG. 6 is a message flow diagram for supporting both L3 CHO and L1/L2 HO in accordance with an embodiment of the present application;

fig. 7 is a message flow diagram of a handover method according to an embodiment of the present application;

fig. 8 is a schematic structural diagram of a possible communication device according to an embodiment of the present application;

fig. 9 is a schematic structural diagram of a terminal device provided in an embodiment of the present application;

fig. 10 is a schematic structural diagram of a network device according to an embodiment of the present application.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present application more apparent, the present application will be described in further detail with reference to the accompanying drawings. The specific methods of operation, functional descriptions, etc. in the method embodiments may also be applied in the apparatus embodiments or the system embodiments.

As shown in fig. 1, the handover method provided in the embodiment of the present application may be applied to a wireless communication system, which may include a terminal device 101 and a network device 102.

It should be appreciated that the above wireless communication system may be applicable to both low frequency scenarios (sub 6G) and high frequency scenarios (above 6G). The application scenario of the wireless communication system includes, but is not limited to, a fifth generation system (5G), a New Radio (NR) communication system, and the like, an existing communication system or a future evolved public land mobile network (public land mobile network, PLMN) system, and the like.

The terminal device 101 shown above may be a User Equipment (UE), a terminal (terminal), an access terminal, a terminal unit, a terminal station, a Mobile Station (MS), a remote station, a remote terminal, a mobile terminal (mobile terminal), a wireless communication device, a terminal agent, a terminal device, or the like. The terminal device 101 may be a communication chip having a communication module, a vehicle having a communication function, an in-vehicle device (e.g., an in-vehicle communication apparatus, an in-vehicle communication chip), or the like. The terminal device 101 may be provided with wireless transceiver functionality that is capable of communicating (e.g., wirelessly communicating) with one or more network devices of one or more communication systems and receiving network services provided by the network devices, including, but not limited to, the illustrated network device 102.

The terminal device 101 may be, among other things, a cellular phone, a cordless phone, a session initiation protocol (session initiation protocol, SIP) phone, a wireless local loop (wireless local loop, WLL) station, a personal digital assistant (personal digital assistant, PDA) device, a handheld device with wireless communication functionality, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a wearable device, a terminal device in a future 5G network or a terminal device in a future evolved PLMN network, etc.

The terminal device 101 may specifically be a mobile phone (mobile phone), a tablet computer (pad), a computer with a wireless transceiving function, a Virtual Reality (VR) terminal, an augmented reality (augmented reality, AR) terminal, a wireless terminal in industrial control (industrial control), a wireless terminal in unmanned driving (self driving), a wireless terminal in remote medical (remote medical), a wireless terminal in smart grid (smart grid), a wireless terminal in transportation security (transportation safety), a wireless terminal in smart city (smart city), a wireless terminal in smart home (smart home), or the like.

In addition, the terminal device 101 may be deployed on land, including indoors or outdoors, hand-held or vehicle-mounted; the terminal device 101 may also be deployed on the water surface (e.g., a ship, etc.); terminal device 101 may also be deployed in the air (e.g., on an airplane, balloon, satellite, etc.). Network device 102 may be an access network device (or access network site). The access network device refers to a device that provides a network access function, such as a radio access network (radio access network, RAN) base station, etc. The network device 102 may specifically include a Base Station (BS), or include a base station, a radio resource management device for controlling the base station, and the like. The network device 102 may also include relay stations (relay devices), access points, and base stations in 5G networks or NR base stations, base stations in future evolution PLMN networks, and so on. Network device 102 may be a wearable device or an in-vehicle device. The network device 102 may also be a communication chip with a communication module.

For example, network device 102 includes, but is not limited to: a base station (G nodeB, gNB) in 5G, an evolved nodeB (eNB) in a long term evolution (long term evolution, LTE) system, a radio network controller (radio network controller, RNC), a radio controller in a cloud radio access network (cloud radio access network, CRAN) system, a base station controller (base station controller, BSC), a home base station (e.g., home evolved nodeB, or home node B, HNB), a baseBand unit (BBU), a transmission point (transmitting and receiving point, TRP), a transmission point (transmitting point, TP), a mobile switching center, a global system for mobile communications (global aystem for mobile communication, GSM), or a base transceiver station (base transceiver station, BTS) in a code division multiple access (code division multiple access, CDMA) network, a node base station (NB) in a wideband code division multiple access (wideband code division multiple access, WCDMA), an evolved NB (eNB or eNodeB) in LTE, an evolved node B (eNB or eNodeB) in future 5G network, an access network in future evolution or a PLMN, or a vehicle-mounted device.

In some deployments, the network device may include Centralized Units (CUs) and Distributed Units (DUs). The network device may also include an active antenna unit (active antenna unit, AAU). The CUs implement part of the functions of the network device, the DUs implement part of the functions of the network device, e.g. the CUs are responsible for handling non-real time protocols and services, implementing radio resource control (radio resource control, RRC), packet data convergence layer protocol (packet data convergence protocol, PDCP) layer functions. The DUs are responsible for handling physical layer protocols and real-time services, implementing the functions of the radio link control (radio link control, RLC), medium access control (media access control, MAC) and Physical (PHY) layers. The AAU realizes part of physical layer processing function, radio frequency processing and related functions of the active antenna. Since the information of the RRC layer may eventually become information of the PHY layer or be converted from the information of the PHY layer, under this architecture, higher layer signaling, such as RRC layer signaling, may also be considered to be transmitted by the DU or by the du+aau. It is understood that the network device may be a device comprising one or more of a CU node, a DU node, an AAU node. In addition, the CU may be divided into network devices in an access network (radio access network, RAN), or may be divided into network devices in a Core Network (CN), which is not limited in this application.

Further, the network device 102 may be connected to a Core Network (CN) device, which may be used to provide core network services for the access network device 102 and the terminal device 101. The core network device may correspond to different devices under different systems. The core network device may correspond to a serving support node (serving GPRS support node, SGSN) of a general packet radio service technology (general packet radio service, GPRS) and/or a gateway support node (gateway GPRS Support Node, GGSN) of GPRS, for example in 3G. In 4G the core network device may correspond to a mobility management entity (mobility management entity, MME) and/or a serving gateway (S-GW). The core network device may correspond to an access and mobility management function (access and mobility management function, AMF), a session management function (session management function, SMF), or a user plane function (user plane function, UPF) in 5G.

For convenience of explanation, the embodiment of the present application uses a terminal device as a UE as an example. In some embodiments of the present application, a network device is taken as an example of a base station, and in other embodiments of the present application, a network device includes a CU and a DU as examples.

The switching method provided by the embodiment of the application is suitable for switching scenes. Next, concepts related to the embodiments of the present application will be described.

1. Cell, source cell, target cell, candidate cell

The network device may configure at least one cell.

In the handover scenario, a cell accessed before handover of the UE is referred to as a source cell, and a cell accessed after handover of the UE is referred to as a target cell. The source cell and the target cell may be configured cells of the same network device, or may be configured cells of different network devices respectively. For example, the network device is a base station. As an example, the source cell is a cell 11 configured by the base station 1, and the target cell is a cell 12 configured by the base station 1. Another example is a cell 11 configured by the base station 1 as the source cell and a cell 21 configured by the base station 2 as the target cell. For example, in a CU-DU separation architecture, a network device includes a CU and a DU. One example is a cell 11 in which the source cell is configured by DU1, and a cell 12 in which the target cell is configured by DU 1. Another example is a cell 11 configured for DU1 as the source cell and a cell 21 configured for DU2 as the target cell. The DU1 and the DU2 may belong to the same CU or may belong to different CUs.

The candidate cell is also called a handover candidate cell or a target candidate cell, and the name is not limited in the embodiment of the present application. In some handover approaches, e.g., L3 CHO and L1/L2 HO, described later, the network device may configure at least one candidate cell for the UE. In these handover modes, the target cell is one of the at least one candidate cell.

2. Source network device, target network device, candidate network device

In the handover scenario, the network device that the UE communicates with before handover is referred to as a source network device, and the network device that the UE communicates with after handover is referred to as a target network device.

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

When the source network device and the target network device are the same, they are referred to as 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 stations 1, the source cell is a cell 11 configured by the base station 1, and the target cell is a cell 12 configured by the base station 1. As another example, a network device includes a CU and a DU. The source network device and the target network device are DU1. The source cell is a cell 11 configured by DU1, and the target cell is a cell 12 configured by DU1.

When the source network device and the target network device are different, they are referred to as a handover between network devices or a handover between different network devices. For example, the network device is a base station, the source network device is a base station 1, and the target network device is a base station 2. For another example, in a CU and DU separation architecture, a network device includes a CU and a DU. The source network device is DU1, and the target network device is DU2. The DU1 and the DU2 may belong to the same CU or may belong to different CUs.

In some handover approaches, such as L3 CHO and L1/L2 HO, described later, the network device communicates with at least one candidate network device to negotiate at least one candidate cell for UE configuration. In these handover patterns, the target network device is one of the at least one candidate network device.

3. L3-based handover and lower layer (L1/L2) -based handover

According to the layered architecture of the protocol stack, generally, L1 (layer 1) includes a physical layer, L2 (layer 2) includes a MAC layer, an RLC layer, and a PDCP layer, and L3 (layer 3) includes an RRC layer. Wherein L1/L2 is also referred to as lower layer. "/" indicates or.

In the present embodiment, the handover includes a lower layer (L1/L2) -based handover and an L3-based handover. Lower layer (L1/L2) based handover is a mobility procedure within the same CU. A lower layer (L1/L2) based handover may also be understood as a handover command issued by layer 1 or layer 2 signaling. The L3-based handover includes a mobility procedure within the same CU (or the same base station) and a mobility procedure between different CUs (or different base stations).

The switching based on the lower layer (L1/L2) issues a switching command or completes the switching process through a MAC Control Element (CE) or downlink control information (downlink control information, DCI), so that the time delay of access can be reduced, and the interruption of service is reduced.

The handover procedure is completed through the RRC layer based on the L3 handover.

4. Handover (L3 Handover or L3 HO)

In the embodiments of the present application, "switching" has a broad meaning and a narrow meaning. A broad term "handover" refers to a mobility procedure of a terminal device in a mobile communication system, and the terminal device may be handed over from one cell to another cell, including various handover modes, such as a lower layer (L1/L2) based handover and an L3 based handover. And narrow "handover" refers to a handover scheme based on L3. For convenience of distinction and description, a narrow sense of "handover" is referred to as L3 handover or L3 HO. Illustratively, embodiments of the present application use the description of L3 HO.

Illustratively, fig. 2 is a message flow diagram of L3 HO provided in an embodiment of the present application, which illustrates L3 HO flows between different base stations (or different CUs). The network elements involved include UE, source base station, target base station, AMF and UFP. For example, the source base station is base station 1, and the target base station is base station 2. In some embodiments, the source base station is also described as a source CU or a source base station/source CU, and the target base station is also described as a target CU or a target base station/target CU.

As shown in fig. 2, in the L3 HO method, the handover method includes:

201. The source base station sends a measurement configuration to the UE.

And the source base station performs measurement configuration on the UE, so that the UE reports a measurement result according to the measurement configuration. The measurement result is used for assisting the source base station in making a handover decision.

The ue sends a measurement report to the source base station (Measurement Report).

203. And the source base station performs switching judgment according to the measurement report.

And the source base station refers to the measurement result reported by the UE and performs switching judgment to determine whether the UE can be switched.

204. The source base station sends a HANDOVER REQUEST (HANDOVER REQUEST) message to the target base station.

The handover request message includes information related to handover preparation. Optionally, the relevant information for handover preparation includes at least: target cell identity, key, UE Identity (ID) at source cell, basic access layer configuration, etc.

205. The target base station performs admission control.

If the target base station allows the UE to handover to the target base station, step 206 is performed.

206. The target base station transmits a handover request acknowledgement (HANDOVER REQUEST ACKNOWLEDGE) message to the source base station.

The target base station performs handover preparation of L3 HO and simultaneously transmits a handover request response message to the source base station. The handover request response message contains configuration information required for accessing the target cell, and at least includes the target cell identifier, the new UE ID and the security algorithm identifier of the target base station. Optionally, the handover command also carries dedicated random access channel (random access channel, RACH) resources for accessing the target cell.

Optionally, the handover command sent to the UE is contained in the handover request ACK message in the form of an RRC container (RRC container).

The handover Request acknowledgement message is also called a handover Request acknowledgement message, a handover Request ACK message, or a HO Request ACK. The handover command may be described as a HO command or a HO command.

For convenience of distinction, the handover command in this embodiment may be referred to as an L3 HO handover command.

207. The source base station sends an RRC reconfiguration (rrcrecon configuration) message to the UE.

The RRC reconfiguration message includes a handover command. Referring to step 206, the handover command is generated by the target base station and transmitted through the source base station, and the source base station performs necessary encryption and integrity protection on the handover command.

After receiving the handover command, the UE performs step 209.

208. The source base station sends a sequence number status transmission (SN STATUS TRANSFER) message to the target base station.

The source base station sends SN STATUS TRANSFER a message to the target base station to transfer the uplink PDCP SN receiving state and the downlink PDCP SN sending state (i.e., RLC AM) of the DRB for which PDCP state preservation is applied. The uplink PDCP SN reception status includes at least the PDCP SN of the first lost UL PDCP SDU, and may include a bit map (bit map) of the reception status of out-of-order UL PDCP SDUs that the UE needs to retransmit in the target cell, if any. The downlink PDCP SN transmission status indicates that the target base station should assign to the next PDCP SN of the new PDCP SDU, but there is no PDCP SN yet. The SN status transfer message is used to maintain continuity of service data during the handoff.

The ue performs synchronization with the target base station.

After receiving the switching command, the UE performs synchronization with the target base station and is used for communicating with the target base station after the switching is successful.

210. The target base station sends a random access response (random access response, RAR) message to the UE.

The RAR message is used for uplink resource allocation and Timing (TA) advance.

Ue sends RRC reconfiguration complete (rrcrecon configuration complete) message to target base station.

The L3 HO is successfully completed, and the UE sends an RRC reconfiguration complete message to the target base station. Correspondingly, the target base station receives the RRC reconfiguration complete message, confirms that the L3 HO is successful, and may start to send data to the UE.

Optionally, the RRC reconfiguration complete message may be accompanied by the transmission of an uplink buffer status report (buffer status report, BSR).

212. The target base station sends a Path Switching (Path Switching) request message to the AMF.

The target base station transmits a path switching request message informing the AMF of cell change, triggers a 5GC switching (DL) data path to the target base station, and establishes an NG-C interface to the target base station. The switching of the air interface has been successfully completed at this time.

AMF sends a User Plane (UP) update request message to UPF.

Upf converts DL links, switching DL data paths to target base stations.

The UPF sends one or more end markers to the source cell, and then can release UP plane/transport network layer resources between the UPF and the source base station.

UPF sends UP update response message to AMF 215.

The amf sends a path switch ACK message to the target base station.

217. And after receiving the path switching ACK message, the target base station sends a UE context release message to the source base station, informs the source base station of successful switching and triggers the source base station to release the UE context.

218. After receiving the UE context release message, the source base station may release the radio bearer and CP resources related to the UE context. If the data forwarding is not completed, the source base station does not release the related resources, and continues the data forwarding until the related resources are released after the data forwarding is completed.

For intra-base station handover, the same is as for inter-base station handover. In the inter-base station handover, the source base station and the target base station in the figure are the same base station, and steps 203-206, 208 may optionally be performed.

5. Condition switching (CHO, L3 Condition switching or L3 CHO)

Conditional handover (conditional handover, CHO) is an L3 based handover scheme, which is done by the RRC layer. The conditional switch can also be described as CHO, L3 conditional switch or L3 CHO. Illustratively, the present embodiments use the L3 CHO description format.

Exemplary, fig. 3 is a message flow diagram of L3 CHO provided in an embodiment of the present application, illustrating L3 CHO flows between different base stations (or different CUs). The network element comprises UE, a source base station, a target base station and a candidate base station, wherein the target base station is also one candidate base station. For example, the source base station is base station 1, the target base station is base station 2, and the candidate base station is base station 3. In some embodiments, the source base station is also described as a source CU or a source base station/source CU, the target base station is also described as a target CU or a target base station/target CU, and the candidate base station is also described as a candidate CU or a candidate base station/candidate CU.

As shown in fig. 3, in the L3 CHO mode, the switching method includes:

301. the source base station configures the UE measurement procedure. Specifically, the source base station sends measurement configuration to the UE, and the UE sends measurement report to the source base station. Reference may be made to the descriptions of steps 201 and 202 in fig. 2, and are not repeated here.

302. The source base station decides to use L3 CHO.

303. The source base station sends a HANDOVER REQUEST (HANDOVER REQUEST) message to the candidate base station.

Wherein the target base station is also a candidate base station.

By sending a handover request message, the source base station requests one or more CHO candidate cells (or L3 CHO candidate cells) belonging to one or more candidate base stations. The source base station sends a handover request message to each L3 CHO candidate cell.

For convenience of distinction, the handover request message in this step may be referred to as CHO handover request message or CHO request message.

304. The candidate base station performs admission control.

If the candidate base station determines that the UE can handover, step 305 is performed.

305. The candidate base station transmits a handover request acknowledgement (HANDOVER REQUEST ACKNOWLEDGE) message to the source base station.

The handover request response message includes CHO configuration including configuration information of the L3 CHO candidate cell and CHO execution conditions. Each L3 CHO candidate cell needs to send a handover request acknowledgement message.

For convenience of distinction, the handover request response message in this step may be referred to as a CHO handover response message or CHO response message.

306. The source base station sends an RRC reconfiguration (rrcrecon configuration) message to the UE.

The RRC reconfiguration message includes the CHO candidate cell configuration.

The ue sends an RRC reconfiguration complete (rrcrecon configuration complete) message to the source base station.

The UE is instructed to receive the RRC reconfiguration message in step 306 through the RRC reconfiguration complete message.

Ue determines that at least one L3 CHO candidate cell satisfies a corresponding CHO execution condition, executing CHO.

Specifically, after receiving the CHO configuration, the UE maintains a connection with the source base station, and starts to evaluate CHO execution conditions of the L3 CHO candidate cell. If at least one L3 CHO candidate cell meets the corresponding CHO execution condition, UE disconnects (detach) from the source base station, and applies the configuration information corresponding to the selected L3 CHO candidate cell to synchronize to the L3 CHO candidate cell, wherein the L3 CHO candidate cell is called a target cell of CHO, and the candidate base station corresponding to the L3 CHO candidate cell is called a target base station.

And successfully CHO, the UE sends an RRC reconfiguration completion message to the target base station to complete the CHO process. After successful completion of CHO, the UE releases the stored CHO configuration.

309. The target base station transmits a HANDOVER SUCCESS (HANDOVER SUCCESS) message to the source base station.

After the UE is disconnected with the source base station and the UE successfully executes CHO, the target base station informs the source base station that the UE is successfully accessed to the target cell.

310. The source base station sends an SN status transmission (SN STATUS TRANSFER) message to the target base station.

Reference may be made to the description of step 208 in fig. 2, which is not repeated here.

311. The source base station sends a HANDOVER CANCEl (HANDOVER CANCEl) message to the other signaling connection or other candidate base station to CANCEl CHO.

It should be noted that the handover procedure shown in fig. 3 may also include message interaction of the core network device, which is not shown in fig. 3, and reference may be made to the descriptions related to steps 212 to 218 in fig. 2, and the principles are similar.

It can be seen that the differences between L3 CHO and L3 HO are: in L3 HO, the network device determines the target cell, and sends configuration information of the target cell to the terminal device through a handover command. And the terminal equipment completes the switching to the target cell according to the configuration information of the target cell. In L3 CHO, at least one L3 CHO candidate cell is configured for the terminal equipment by the network equipment, and the CHO configuration is sent to the terminal equipment, wherein the configuration information and CHO execution conditions of the L3 CHO candidate cell are included. And the terminal equipment determines a target cell according to the CHO execution condition and completes the switching to the target cell according to the stored configuration information of the target cell.

6. L1/L2 handover (or L1/L2 HO)

Exemplary, fig. 4 is a message flow diagram of L1/L2 HO provided in the embodiment of the present application, which illustrates an L1/L2 HO procedure between different DUs in the same CU under a CU-DU separation architecture. The network elements involved include UE, source DU, target DU, candidate DU and CU, the target DU being also a candidate DU. For example, the source DU is DU1, the target DU is DU2, and the candidate DU is DU3. In some embodiments, CU is also described as a base station or CU/base station.

As shown in fig. 4, in the L1/L2 HO method, the handover method includes:

cu sends measurement configuration to UE.

The ue sends a measurement report to the CU (Measurement Report). Alternatively, the measurement report in this step is a through L3 measurement report.

Cu sends a HANDOVER REQUEST message to candidate DUs.

The CU decides to use L1/L2 HO and requests one or more L1/L2 HO candidate cells belonging to one or more candidate DUs by sending a handover request message. Optionally, the CU sends a handover request message to each L1/L2 HO candidate cell.

Wherein the target DU is also a candidate DU.

For convenience of distinction, the handover request message in this step may be referred to as an L1/L2 HO handover request message or an L1/L2 HO request message.

403. The candidate DUs perform admission control.

If the candidate DU determines that the UE can handover, step 404 is performed.

404. The candidate DU sends a handover request acknowledgement (HANDOVER REQUEST ACKNOWLEDGE) message to the CU.

The handover request response message contains L1/L2HO configuration, wherein the L1/L2HO configuration comprises configuration information of L1/L2HO candidate cells. Optionally, each L1/L2HO candidate cell needs to send a handover request acknowledgement message.

For convenience of distinction, the handover request acknowledgement message in this step may be referred to as an L1/L2HO handover response message or an L1/L2HO response message.

405. The source DU sends an RRC reconfiguration (rrcrecon configuration) message to the UE.

The RRC reconfiguration message contains L1/L2HO configuration and candidate cell configuration information.

Optionally, step 405a may be included, where the UE sends an RRC reconfiguration complete message to the source DU, indicating that the UE receives the RRC reconfiguration message in step 405.

The ue sends a measurement report to the source DU (Measurement Report). Alternatively, the measurement report in this step is a through L1 measurement report.

The measurement report is used to assist the source DU in making handoff decisions.

407. The source DU makes a handover decision based on the measurement report of L1.

408. The source DU sends a handover command message to the UE.

The RRC reconfiguration message includes a handover command indicating that the UE completes the cell change through L1/L2 HO. The handover command includes at least the target cell identity. The target cell is one L1/L2HO candidate cell among the L1/L2HO candidate cells included in step 405.

For ease of distinction, the handover command in this embodiment may be referred to as an L1/L2HO handover command.

409. The source DU sends a sequence number status transfer (SN STATUS TRANSFER) message to the target DU.

Ue performs synchronization with a target DU.

Ue sends a handover complete message to the target DU.

The L1/L2HO is successfully completed, and the UE sends a handover complete message to the target DU. In the L1/L2 based handover, the handover complete message is in the form of MAC CE or DCI. Correspondingly, the target DU receives the handover complete message, confirms that the L1/L2HO is successful, and can start to send data to the UE.

Alternatively, when the UE is to perform a continuous L1/L2HO (sub sequence L1/L2 handover), this means that the UE does not release the L1/L2HO configuration after completing one access to the target cell, but continues to maintain the L1/L2HO configuration, and performs a subsequent L1/L2 HO.

Optionally, in a scenario supporting a subsequent L1/L2 handover, in step 405, a target cell for the subsequent L1/L2 handover may also be included. See the fourth embodiment which follows.

It should be noted that the handover procedure shown in fig. 4 may also include message interaction of the core network device, which is not shown in fig. 4, and reference may be made to the descriptions related to steps 212 to 218 in fig. 2, and the principles are similar.

It can be seen that the differences between L1/L2 HO and L3 HO are: in the L3 HO, after the network device determines the target cell, the configuration information of the target cell is sent to the terminal device through a handover command. And the terminal equipment completes L3 HO to the target cell according to the configuration information of the target cell. In L1/L2 HO, a network device configures at least one L1/L2 HO candidate cell for a terminal device, and sends L1/L2 HO configuration including configuration information of the L1/L2 HO candidate cell to the terminal device. And then, the network equipment determines a target cell and sends the target cell identification to the terminal equipment through a switching command. Wherein the target cell is one L1/L2 HO candidate cell of the L1/L2 HO candidate cells. And the terminal equipment completes L1/L2 HO to the target cell according to the previously stored configuration information of the target cell.

The same points for L1/L2 HO and L3 HO are: the target cell is determined by the network device.

The differences between L1/L2 HO and L3 CHO are: in the L3 CHO, after the network equipment configures at least one L3 CHO candidate cell for the terminal equipment, the terminal equipment determines a target cell according to CHO execution conditions. In L1/L2 HO, after the network device configures at least one L1/L2 HO candidate cell for the terminal device, the network device determines a target cell.

The same points for L1/L2 HO and L3 CHO are: the network device is configured with candidate cells for handover.

7. Switching flow for terminal equipment and network equipment to support L3 HO and L1/L2 HO simultaneously

In the embodiment of the application, the terminal equipment supports a plurality of switching modes, wherein the switching modes comprise switching based on a lower layer (L1/L2) and switching based on L3. One implementation is as follows: the terminal device and the network device support both L3 HO and L1/L2 HO.

Fig. 5 is a message flow diagram of a terminal device and a network device supporting L3 HO and L1/L2 HO according to an embodiment of the present application. The network element involved comprises at least a UE, a source DU, a target DU, a candidate DU and a CU, the target DU being also a candidate DU. In some embodiments, CU is also described as a base station or CU/base station.

As shown in fig. 5, in a scenario where L3 HO and L1/L2 HO are simultaneously supported, the handover method includes:

400-405 a, see the relevant description in fig. 4, and are not repeated here.

207 and 211, see the relevant description in fig. 2, and are not described here again.

In the present embodiment, the order between steps 400 to 405a and steps 207 and 211 is not strictly limited, and may be changed and omitted.

After success of the L3 HO, the configuration of the L1/L2 HO candidate cell is processed.

Specifically, the UE completes L3 HO, assuming handover from cell 0 to cell 1. The UE keeps the configuration of the L1/L2 HO candidate cells received at cell 0, e.g., L1/L2 HO candidate cells include cell 11, cell 12 and cell 13. However, after the UE is handed over to cell 1, cell 11, cell 12 and cell 13 may not be suitable for cell 1. Therefore, it is necessary to process the configuration of the L1/L2 HO candidate cells to improve the success rate of subsequent handover. The specific implementation of step 501 may be referred to the description of S704 in the subsequent embodiments.

Alternatively, the target cell of the L3 HO may be one of the L1/L2 HO candidate cells or not.

Alternatively, the target cell of the L3 HO may be a cell in the CU, or may be a cell under another CU.

It should be noted that the handover procedure shown in fig. 5 may further include other messages, which are not limited in this embodiment of the present application. For example, between 207 and 211, 208-210 in FIG. 2 may also be included.

It should be noted that the handover procedure shown in fig. 5 may also include message interaction of the core network device, which is not shown in fig. 5, and reference may be made to the descriptions related to steps 212 to 218 in fig. 2, and the principles are similar.

8. Terminal equipment and network equipment simultaneously support switching flow of L3 CHO and L1/L2 HO

In the embodiment of the application, the terminal equipment supports a plurality of switching modes, wherein the switching modes comprise switching based on a lower layer (L1/L2) and switching based on L3. One implementation is as follows: the terminal equipment and the network equipment support both L3 CHO and L1/L2 HO.

Illustratively, fig. 6 is a message flow diagram for supporting both L3 CHO and L1/L2 HO according to an embodiment of the present application. The network element involved comprises at least a UE, a source DU, a target DU, a candidate DU and a CU, the target DU being also a candidate DU. Here, CU denotes a source CU before UE handover. Optionally, the involved network elements may further include a target CU and a candidate CU. In some embodiments, CU is also described as a base station or CU/base station.

As shown in fig. 6, in a scenario where L3 CHO and L1/L2 HO are supported simultaneously, the handover method includes:

400-405 a, see the relevant description in fig. 4, and are not repeated here.

302. 306, 307, and 308, reference may be made to the relevant descriptions in fig. 3, and are not repeated here.

In the present embodiment, the order between steps 400 to 405a and steps 302, 306, 307, and 308 is not strictly limited, and may be changed or omitted.

After success of L3 CHO, the configuration of L1/L2 HO candidate cells is processed.

Specifically, the UE completes L3 CHO, assuming that a handover is made from cell 0 to cell 1, cell 1 being one L3 CHO candidate cell of the at least one L3 CHO candidate cell configured by the CU. The UE keeps the configuration of the L1/L2 HO candidate cells received at cell 0, e.g., L1/L2 HO candidate cells include cell 11, cell 12 and cell 13. However, after the UE switches to cell 1, when cell 1 is a serving cell, cells 11, 12 and 13 may not be suitable for cell 1, i.e., may not continue to be candidate cells for handover from cell 1. Therefore, it is necessary to process the configuration of the L1/L2 HO candidate cells to improve the success rate of subsequent handover. The specific implementation of 601 may be found in the description of S704 in the subsequent embodiments.

Alternatively, the target cell of L3 CHO may be one of the L1/L2 HO candidate cells or not.

Alternatively, the target cell of L3 CHO may be a cell in the CU where the current serving cell is located, or may be a cell under another CU.

It should be noted that the handover procedure shown in fig. 6 may further include other messages, which are not limited in this embodiment of the present application. For example, 303 to 305, 309 to 311, etc. in fig. 3 may be included.

It should be noted that the handover procedure shown in fig. 6 may also include message interaction of the core network device, which is not shown in fig. 6, and reference may be made to the descriptions related to steps 212 to 218 in fig. 2, and the principles are similar.

9、L1/L2 CHO

The embodiment of the application also provides a switching based on L1/L2, which is called L1/L2 CHO. The handoff procedure for L1/L2 CHO is similar to L1/L2 HO. For example, as shown in FIG. 4, L1/L2 CHO differs from L1/L2 HO in steps 406-408 in FIG. 4. For L1/L2 CHO, steps 406-408 are similar to L3 CHO, and the UE evaluates candidate cells (specifically L1/L2 CHO candidate cells) for handover.

The technical scheme of the present application is described in detail below through specific examples.

In the embodiments of the present application, the same or similar parts between the embodiments may be referred to each other unless specifically described otherwise. In the various embodiments and the various implementation/implementation methods in the various embodiments in this application, if no special description and logic conflict exist, terms and/or descriptions between different embodiments and between the various implementation/implementation methods in the various embodiments may be consistent and may be mutually referred to, technical features in the different embodiments and the various implementation/implementation methods in the various embodiments may be combined to form new embodiments, implementations, implementation methods, or implementation methods according to their inherent logic relationships. The above-described embodiments of the present application are not intended to limit the scope of the present application. In each of the embodiment steps, it may be partially performed (for example, the terminal device may not perform the steps performed by the terminal device in the above embodiments). The order of execution of the different steps may be altered. The embodiments described herein may be combined with other embodiments, and the steps of the different embodiments herein may also be combined.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

The terms "first," "second," "third," "fourth," and the like in embodiments of the present application, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order.

In the embodiments of the present application, "including" may be an inclusive relationship or an equal relationship. For example, a includes B, and a may include other content in addition to B, or a and B may be the same content.

In the description of the present application, unless otherwise indicated, "/" means that the associated object is an "or" relationship, e.g., a/B may represent a or B; the term "and/or" in this application is merely an association relation describing an association object, and means that three kinds of relations may exist, for example, a and/or B may mean: there are three cases, a alone, a and B together, and B alone, wherein a, B may be singular or plural. Also, in the description of the present application, unless otherwise indicated, "a plurality" means two or more than two. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (one) of a, b, or c may represent: a, b, c, a-b, a-c, b-c, or a-b-c, wherein a, b, c may be single or plural. In addition, in order to clearly describe the technical solutions of the embodiments of the present application, in the embodiments of the present application, the words "first", "second", and the like are used to distinguish the same item or similar items having substantially the same function and effect. It will be appreciated by those of skill in the art that the words "first," "second," and the like do not limit the amount and order of execution, and that the words "first," "second," and the like do not necessarily differ.

In the embodiments of the present application, "of", "corresponding" and "corresponding" may be sometimes used in combination, and it should be noted that the meaning to be expressed is consistent when the distinction is not emphasized.

In the embodiments of the present application, words such as "exemplary," "for example," and the like are used to indicate by way of example, illustration, or description. Any embodiment or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments or designs. Rather, the term use of an example is intended to present concepts in a concrete fashion.

The embodiment of the application is suitable for a scenario that the switching based on the L1/L2 and the switching based on the RRC are configured at the same time. For convenience of description, L1/L2 based handover takes L1/L2 HO as an example, and a scenario in which L1/L2 HO and L3 HO/CHO are simultaneously configured is described. It should be noted that the embodiments of the present application are also applicable to L1/L2 CHO, and are applicable to the scenario where L1/L2 CHO and L3 HO/CHO are configured simultaneously. In some embodiments, L1/L2 HO may be replaced with L1/L2 CHO.

Example 1

Fig. 7 is a message flow diagram of a handover method according to an embodiment of the present application. The switching method provided in this embodiment, the execution body includes a terminal device and a network device. The terminal device is illustratively a UE, and the network device includes a CU and a DU. As shown in fig. 7, the switching method provided in this embodiment may include:

S701, the network equipment sends a first message to the terminal equipment. The first message includes configuration information of M first candidate cells for the first handover, M being a positive integer.

Accordingly, the terminal device receives the first message from the network device.

In the first handover, the network device configures M first candidate cells for the terminal device. The value of M is not limited in this embodiment.

Alternatively, the first handover is a lower layer (L1/L2) based handover.

Optionally, in one implementation, the target cell of the first handover is configured by the network device. Optionally, in another implementation manner, the terminal device determines a target cell of the first handover according to the M first candidate cells, where the target cell of the first handover is one of the M first candidate cells.

Alternatively, the first handover is an L1/L2 HO, see also the relevant description of FIG. 4.

Optionally, the first message is an RRC reconfiguration message, see step 405 in fig. 4.

For convenience of explanation, the embodiment of the present application takes the first handover to L1/L2 HO as an example.

S702, the network equipment sends a second message to the terminal equipment. The second message includes configuration information of the target cell of the second handover.

Correspondingly, the terminal device receives a second message from the network device.

Optionally, the first message and the second message are the same or different.

The first message and the second message are the same, which means that the first message and the second message are one message, thereby saving the overhead of air interface signaling. At this time, S701 and S702 are: the network device sends a first message to the terminal device, the first message comprising: the configuration information of M first candidate cells of the first handover and the configuration information of a target cell of the second handover, M being a positive integer. Here, the first message may be replaced with the second message.

The first message and the second message are different, meaning that the first message and the second message are separate messages.

Alternatively, the second handover is an RRC-based handover.

In one implementation, the second handover is an L3 HO. The second message is also used to indicate a target cell for the second handover.

In this implementation, both the terminal device and the network device support L3 HO and L1/L2 HO, and the handover procedure may be seen in fig. 5. The terminal device is UE, and the network device includes CU and DU. Illustratively, the first message is an RRC reconfiguration message in step 405 of fig. 5. The second message is the RRC reconfiguration message in step 207 of fig. 5. Optionally, the second message is an RRC reconfiguration message. The second message includes a handover command including configuration information of the target cell of the L3 HO. The handover command may be described with reference to step 206 and step 207 in fig. 2.

In another implementation, the second switch is L3 CHO. The second message includes configuration information of N second candidate cells subjected to conditional switching and conditional switching execution conditions, wherein N is a positive integer, and the N second candidate cells comprise target cells subjected to the second switching. The value of N is not limited in this embodiment.

In this implementation, both the terminal device and the network device support L3 CHO and L1/L2 HO, and the handover procedure can be seen in fig. 6. The terminal device is UE, and the network device includes CU and DU. The first message is an RRC reconfiguration message in step 405 of fig. 6. The second message is an RRC reconfiguration message in step 306 in fig. 6. Optionally, the second message is an RRC reconfiguration message.

Optionally, in the implementation supporting L3 CHO and L1/L2 HO shown in fig. 6, the first message and the second message are the same, e.g. RRC reconfiguration message in step 405 or step 306 in fig. 6. At this time, the RRC reconfiguration message includes: configuration information of M first candidate cells for the first handover, configuration information of N second candidate cells for the conditional handover, and conditional handover execution conditions.

S703, the terminal device executes the second switching according to the second message.

The terminal equipment can determine the information of the target cell of the second handover according to the second message, and execute the second handover according to the configuration information of the target cell of the second handover.

Optionally, in the implementation supporting L3 HO and L1/L2 HO shown in fig. 5, the network device determines a target cell for the L3 HO, and the second message includes configuration information of the target cell for the L3 HO. After receiving the second message, the terminal device executes the L3 HO according to the configuration information of the target cell of the L3 HO.

Optionally, in the implementation supporting L3 CHO and L1/L2 HO shown in fig. 6, the network device configures N L3 CHO candidate cells for the terminal device. The second message includes configuration information of N second candidate cells for conditional handover and a conditional handover execution condition of each candidate cell. After receiving the second message, the terminal equipment switches the execution conditions according to the conditions of the N L3 CHO candidate cells, performs CHO evaluation, determines the target cell of the L3 CHO meeting the conditions, and executes the L3 CHO according to the configuration information of the target cell of the L3 CHO.

S704, the second switching is successfully completed, and the terminal equipment executes a first operation. The first operation includes reserving, releasing, or reconfiguring configuration information of the M first candidate cells.

And the second switching is successfully completed, and the terminal equipment is switched to a target cell of the second switching. The configuration information of the first candidate cell, which is configured in consideration of the network before, may not be suitable for the target cell of the second handover. The UE can avoid the occupation of memory caused by invalid storage of the configuration of the first candidate cell by releasing or reconfiguring the configuration information of the first candidate cell, thereby improving the switching success rate and the performance of the terminal equipment. Considering that the configuration information of the first candidate cell sent by the base station occupies air interface resources, the UE reserves the configuration information of the first candidate cell, so that the base station is prevented from frequently sending the configuration of the first candidate cell to the UE, signaling overhead is saved, and the UE can complete the first handover faster based on the reserved configuration of the first candidate cell, thereby improving the success rate of the handover.

The "configuration information of the M first candidate cells" in S704 refers to the configuration information of the M first candidate cells carried in the second message, and does not necessarily describe that the first operation as a whole is necessarily performed. Alternatively, the object of the first operation may be configuration information of all the first candidate cells in the M first candidate cells, or may be configuration information of part of the first candidate cells in the M first candidate cells.

The first operation includes any one of:

the configuration information of all first candidate cells in the M first candidate cells is reserved; or,

reserving configuration information of part of first candidate cells in the M first candidate cells; or,

releasing configuration information of all first candidate cells in the M first candidate cells; or,

releasing configuration information of part of first candidate cells in the M first candidate cells; or,

reconfiguring configuration information of all first candidate cells in the M first candidate cells; or,

and reconfiguring configuration information of part of the first candidate cells in the M first candidate cells.

It can be seen that the handover method provided in this embodiment is applicable to a scenario in which the terminal device and the network device support the first handover and the second handover simultaneously. In the first handover, the network device configures a first candidate cell for the terminal device for the first handover. After the terminal equipment performs the second handover and completes the second handover successfully, the configuration information of the first candidate cell is reserved, released or reconfigured, so that the situation that the memory is occupied due to invalid storage of the configuration of the first candidate cell is avoided, or signaling overhead is saved, and the handover success rate is improved.

Optionally, in S704, the second handover is successfully completed, and the terminal device executes a first operation, including:

the terminal equipment executes the second switching, and the terminal equipment executes the first operation; or,

the terminal equipment sends a switching completion message, and the terminal equipment executes a first operation; or,

the terminal equipment completes the random access to the target cell of the second handover, and the terminal equipment executes the first operation.

Optionally, the switching method provided in this embodiment may further include:

and the second handover fails, and the terminal equipment executes RRC reestablishment.

The RRC reestablishes that the selected target cell is a first candidate cell in the M first candidate cells, and the terminal equipment executes first switching according to the configuration information of the first candidate cell associated with the target cell.

In this implementation, the UE fails to perform the second handover, and the original procedure is to perform RRC reestablishment. However, if the target cell of RRC re-establishment is the first candidate cell, access delay and interruption of service are reduced by preferentially performing the first handover.

Optionally, the second handover is a conditional handover, and the second message includes configuration information of N second candidate cells for the conditional handover, where N is a positive integer. The switching method provided in this embodiment may further include:

The RRC reestablishes the selected target cell as a second candidate cell in the N second candidate cells, and the terminal equipment executes conditional switching according to the second candidate cell.

In this implementation, the UE fails to perform the second handover, and the original procedure is to perform RRC reestablishment. However, if the target cell re-established by the RRC is the second candidate cell, the access delay and interruption of the service are reduced by preferentially performing the conditional handover.

Example two

Based on the embodiment shown in fig. 7, the switching method provided in another embodiment of the present application provides an implementation manner of S704. Alternatively, the scenario shown in FIG. 5 for L3 HO and L1/L2 HO support, and the scenario shown in FIG. 6 for L3 CHO and L1/L2 HO support are applicable.

In this embodiment, the second message further includes indication information indicating that configuration information of all of the M first candidate cells or at least one of the M first candidate cells is reserved, released, or reconfigured.

Specifically, the indication information is used for indicating, after the terminal equipment is switched to the second switched target cell, or completes random access to the second switched target cell, or executes the second switch or the terminal equipment sends a switch completion message, and the terminal equipment reserves, releases or reconfigures configuration information of all or at least one first candidate cell in the M first candidate cells.

Accordingly, in S704, the terminal device performs a first operation, including:

and the terminal equipment reserves, releases or reconfigures configuration information of all or part of the first candidate cells in the M first candidate cells according to the indication information.

Wherein the indication information indicates any one of the following:

reserving configuration information of at least one first candidate cell in the M first candidate cells; or,

releasing configuration information of at least one first candidate cell in the M first candidate cells; or,

and reconfiguring configuration information of at least one first candidate cell in the M first candidate cells.

Accordingly, the first operation includes any one of the following:

It can be seen that, in this embodiment, the network device instructs, through the indication information, the terminal device to process the configuration information of the M first candidate cells, and the terminal device performs the first operation according to the indication information, so that the implementation manner is simple. In addition, the first candidate cell is configured by the base station, and the base station can accurately determine whether to release the configuration of the L1/L2 HO candidate cell, so that the accuracy of the configuration is ensured, and the success rate of switching is further improved.

Optionally, in the implementation supporting L3 HO and L1/L2 HO shown in fig. 5, the second message is an RRC reconfiguration message in step 207 in fig. 5. The RRC reconfiguration message also includes indication information. Alternatively, the indication information may be included in the handover command. For example, the indication information when L3 HO is an L3 HO scene within the same CU may be included in the handover command. Alternatively, the indication information may be included in the second message outside the handover command.

Optionally, in the implementation supporting L3 CHO and L1/L2 HO shown in fig. 6, the second message is an RRC reconfiguration message in step 306 in fig. 6. The RRC reconfiguration message also includes indication information.

Next, an implementation of the instruction information will be described.

1. In a first implementation of the indication information, the indication information is a 1-bit indication information.

The 1-bit indication information indicates that configuration information of all first candidate cells in the M first candidate cells is reserved or not released, or the 1-bit indication information indicates that configuration information of all first candidate cells in the M first candidate cells is released or not reserved.

In this implementation, the configuration information for all M first candidate cells indicates either all reservations (i.e., all are not released) or all releases (i.e., all are not reserved) by the 1-bit indication information. Moreover, the indication information is only 1 bit, the signaling overhead is small, and the air interface resource is saved.

Optionally, the 1-bit indication information includes a first value and a second value.

Optionally, when the 1-bit indication information is the first value, the configuration information of all the first candidate cells in the M first candidate cells is indicated to be reserved or not released. And when the 1-bit indication information is the second value, indicating to release or not to reserve the configuration information of all the first candidate cells in the M first candidate cells.

In this embodiment, the first value and the second value are not limited. Some examples are: the first value is 1, and the second value is 0; or, the first value is 0, and the second value is 1; or, the first value is true, and the second value is false; alternatively, the first value is false and the second value is true.

2. In a second implementation of the indication information, the indication information is a first bit map indication information.

In order to distinguish between different bit map indication information (bitmaps), it is referred to as first bit map indication information in this implementation.

The first bit map indicating information has S bits, S being a positive integer less than or equal to N. Optionally, each bit is 1 bit of indication information in the first implementation of the indication information. Alternatively, the first bit map indication information includes S1-bit indication information. S1-bit indication information associates S objects. For each object, the configuration information for all M first candidate cells may be indicated by the 1-bit indication information associated with the object as either all reserved (i.e., all not released) or all released (i.e., all not reserved).

It can be seen that in this implementation, the indication information has S bits, and S objects are associated in a bit-mapped manner. For different objects, the 1-bit indication information associated by the object indicates configuration information of all reserved (i.e., all not released) or all released (i.e., all not reserved) M first candidate cells. The implementation of the indication information is more flexible.

Alternatively, in one implementation, the first bit map indication information is applied to the scenario supporting L3 CHO and L1/L2 HO shown in fig. 6. The first bit map indication information includes S1-bit indication information, and S second candidate cells among the N second candidate cells are associated with 1-bit indication information. That is, the S subjects are S L3 CHO candidate cells among the N L3 CHO candidate cells. In this way, for each L3 CHO candidate cell of the S L3 CHO candidate cells, whether all the configuration information of the M first candidate cells are reserved (i.e., not released) or released (i.e., not reserved) is indicated by the associated 1-bit indication information, so that the success rate of handover is improved, and the indication mode is more flexible and reasonable.

In this embodiment, the order or position of the S L3 CHO candidate cells among the N L3 CHO candidate cells is not limited. For example, the first S L3 CHO candidate cells of the N L3 CHO candidate cells may be the first S L3 CHO candidate cells of the N L3 CHO candidate cells, or the last S L3 CHO candidate cells of the N L3 CHO candidate cells, or any S L3 CHO candidate cells of the N L3 CHO candidate cells.

Optionally, when N > S, there are N-S second candidate cells unassociated with 1-bit indication information in addition to S second candidate cells in the N second candidate cells.

Optionally, in an implementation manner, the terminal device releases configuration information of all M first candidate cells for N-S second candidate cells not associated with the first bit mapping indication information.

Optionally, in another implementation, the terminal device reserves configuration information of all M first candidate cells for N-S second candidate cells not associated with the first bit map indication information.

For example.

N= 5,S =3. The N second candidate cells include L3 CHO candidate cells 1 to L3 CHO candidate cell 5. The M first candidate cells include L1/L2 HO candidate cells 1 to L1/L2 HO candidate cell 3. The first bit map indicating information has 3 bits. The 1 bit indication information has a value of 1 and indicates that the configuration information of all M first candidate cells is released. The value of the 1-bit indication information is 0, which indicates that the configuration information of all M first candidate cells is released.

In one example, the first bit map indicates that the value of the information is binary 110. The first bit map indication information corresponds to the first 3L 3 CHO candidate cells, specifically L3 CHO candidate cells 1 to L3 CHO candidate cell 3. Then, configuration information of the L1/L2 HO candidate cells 1 to L1/L2 HO candidate cell 3 is released for the L3 CHO candidate cell 1 and the L3 CHO candidate cell 2. And reserving configuration information of the L1/L2 HO candidate cells 1-L1/L2 HO candidate cell 3 for the L3 CHO candidate cell 3.

The L3 CHO candidate cell 4 and the L3 CHO candidate cell 5 are not associated with the first bit map indication information.

In one implementation, configuration information for L1/L2 HO candidate cells 1-L1/L2 HO candidate cell 3 is released for L3 CHO candidate cell 4 and L3 CHO candidate cell 5.

In another implementation, configuration information of L1/L2 HO candidate cells 1-L1/L2 HO candidate cell 3 is reserved for L3 CHO candidate cell 4 and L3 CHO candidate cell 5.

3. In a third implementation of the indication information, the indication information comprises a configuration identity of the at least one cell, the configuration identity being associated with configuration information of the at least one first candidate cell.

Wherein the configuration identity of the cell is used to distinguish between different cells. Optionally, the configuration identity of the cell includes any one of the following: physical cell identity (physical cell identifier, PCI) or cell ID or any other cell identity.

In this embodiment, the number of configuration identifiers included in the indication information is not limited, or, the number of at least one first candidate cell associated with the configuration information of the cell is not limited. May be a positive integer less than or equal to M. Let us assume that it is marked J. If M > J, then J configuration identities associate J first candidate cells, M-J first candidate cells being present in the M first candidate cells in addition to the J first candidate cells.

Optionally, in one implementation, the configuration identifier of at least one (J) cells included in the indication information is associated with at least one first candidate cell (J), so that configuration information of the first candidate cell (J) is reserved after the terminal device is switched to the target cell, and the configuration information of the first candidate cell (M-J) is released after the terminal device is switched to the target cell.

Optionally, in another implementation, the configuration identifier of at least one (J) cells included in the indication information identifies associated at least one first candidate cell (J), so that configuration information of the first candidate cell (J) is released after the terminal device is switched to the target cell, and the configuration information of the first candidate cell (M-J) is reserved after the terminal device is switched to the target cell.

For example.

It is assumed that the configuration of the cell is identified as a cell ID. M=5, and the M first candidate cells are cell 1 to cell 5, and the cell IDs are 1 to 5, respectively. The indication information includes cell IDs of 3 cells, which are 2, 3 and 5, respectively, corresponding to cell 2, cell 3 and cell 5. In one implementation, configuration information for cell 2, cell 3, and cell 5 is reserved, releasing configuration information for cell 1 and cell 4. In another implementation, the configuration information of cell 2, cell 3, and cell 5 is released, and the configuration information of cell 1 and cell 4 is reserved.

It can be seen that, in this embodiment, by carrying the configuration identifier of the cell in the indication information, the configuration information of the first candidate cell associated with the configuration identifier of the cell may be released or reserved. Furthermore, configuration information of at least one first candidate cell of the M first candidate cells may be released or reserved. The implementation is flexible.

Optionally, the indication information includes a PCI of at least one cell, the PCI of at least one cell being associated with configuration information of at least one first candidate cell.

In this implementation, the configuration identifier of the cell is PCI, and the configuration information of the first candidate cell associated with the PCI is indicated to be released or reserved by carrying the PCI of the cell in the indication information.

4. In a fourth implementation of the indication information, the indication information is a second bit map indication information.

In order to distinguish between different bitmap indication information (bitmaps), in this implementation, it is referred to as second bitmap indication information.

The second bit mapping indication information includes K bits, that is, K1 bits of indication information, where K first candidate cells in the M first candidate cells are associated with 1 bit of indication information, and K is a positive integer less than or equal to M. Specifically, the second bit map indication information has K bits, each bit being 1 bit indication information, associated with one of the M first candidate cells. The second bit map indication information includes K1-bit indication information associated with K first candidate cells among the M first candidate cells. In this implementation, the 1-bit indication information indicates to retain or release configuration information of the corresponding first candidate cell.

Optionally, when the 1-bit indication information is a first value, the indication is to keep the configuration information of the corresponding first candidate cell. And when the 1-bit indication information is the second value, indicating to release the configuration information corresponding to the first candidate cell.

In this embodiment, the order or the positions of the K first candidate cells in the M first candidate cells are not limited. For example, the first K first candidate cells of the M first candidate cells may be the first K first candidate cells, or the last K first candidate cells of the M first candidate cells may be the first K first candidate cells of the M first candidate cells, or any K first candidate cells of the M first candidate cells may be the first K first candidate cells.

Optionally, when M > K, there is M-K first candidate cells unassociated with 1-bit indication information in addition to K first candidate cells in the M first candidate cells.

Optionally, in one implementation, the terminal device releases configuration information of the M-K first candidate cells.

Optionally, in another implementation, the terminal device reserves configuration information of the M-K first candidate cells.

For example.

In one example, m=5, and M first candidate cells are cell 1 to cell 5. K=5, and the second bit map indication information includes 5 1-bit indication information corresponding to 5 first candidate cells.

In another example, m=5, and M first candidate cells are cell 1 to cell 5. K=3, and the second bit map indication information includes 3 1-bit indication information corresponding to 3 first candidate cells. Assume that the value of the second bit map instruction information is binary 101. A value of 0 for the 1-bit indication information indicates that the configuration information of the corresponding first candidate cell is released, and a value of 1 for the 1-bit indication information indicates that the configuration information of the corresponding first candidate cell is reserved.

It is assumed that the second bitmap indication information corresponds to the last 3 cells (cell 3 to cell 5) of cells 1 to 5. Then, as known from the second bitmap indication information, the configuration information of the cell 3 and the cell 5 is reserved, and the configuration information of the cell 4 is released.

For cell 1 and cell 2, in one implementation, configuration information for cell 1 and cell 2 is reserved. In another implementation, the configuration information for cell 1 and cell 2 is released.

It can be seen that in this implementation, the indication information has K bits, and K first candidate cells are associated in a bit map manner. For a different first candidate cell, the configuration information of the first candidate cell is reserved or released through the 1-bit indication information associated with the first candidate cell. The success rate of switching is improved, and the implementation mode of the indication information is more flexible.

5. In a fifth implementation of the indication information, the indication information comprises reconfiguration information of the first candidate cell.

The reconfiguration information is used to indicate at least one of the following: releasing configuration information of part of the first candidate cells in the M first candidate cells, adding configuration information of at least one candidate cell except the M first candidate cells, releasing configuration information of the M first candidate cells or reserving configuration information of the M first candidate cells.

In this implementation, the indication information includes reconfiguration information. According to the reconfiguration information, configuration information of all or part of the first candidate cells may be reserved or released for M first candidate cells that have been saved by the terminal device. And the configuration information of the new candidate cell can be added according to the reconfiguration information, so that the effect of reconfiguring the configuration of the first candidate cell is achieved, and the implementation mode is more flexible.

Optionally, the indication information is a reconfiguration message. The reconfiguration message contains configuration information of candidate cells except M candidate cells, and the terminal equipment adds configuration information of at least one candidate cell except M first candidate cells based on the reconfiguration message.

Optionally, the reconfiguration information of the first candidate cell may include a field of a setupelease structure. In this manner, as an example, for any one of the M first candidate cells, if the reconfiguration information includes a configuration for the candidate cell and is set to "release", the release of the candidate cell is instructed; or if the reconfiguration information does not contain the configuration for any candidate cell in the M first candidate cells, indicating to reserve the candidate cell and the configuration information of the candidate cell; or, the reconfiguration information includes configuration for any candidate cell of the M first candidate cells or the reconfiguration information includes configuration for any candidate cell of the M first candidate cells and is set as "setup", and then the any candidate cell is reserved and reconfigured according to the configuration.

Example III

On the basis of the embodiment shown in fig. 7, a handoff method provided in another embodiment of the present application provides an implementation manner of S704. Alternatively, the scenario shown in FIG. 5 for L3 HO and L1/L2 HO support, and the scenario shown in FIG. 6 for L3CHO and L1/L2 HO support are applicable. In this embodiment, the terminal device reserves or releases configuration information of M first candidate cells according to the target cell of the second handover. Because the terminal equipment determines the mode of processing the configuration information of the M first candidate cells, the network side is not required to send the indication information, the air interface signaling overhead is saved, and the implementation mode is flexible.

In the handover method provided in the present embodiment, in S704, the terminal device executes a first operation, including:

the target cell of the second handover is a first candidate cell of the M first candidate cells, and the terminal device reserves configuration information of the M first candidate cells, or the terminal device reserves configuration information of a first candidate cell related to the target cell of the second handover of the M first candidate cells. Or alternatively, the first and second heat exchangers may be,

the target cell of the second handover is not a first candidate cell of the M first candidate cells, and the terminal device releases configuration information of the M first candidate cells.

Specifically, if the target cell of the second handover is a first candidate cell of the M first candidate cells, this means that when the terminal device is handed over to one candidate cell of the M first candidate cells, for the target cell after the handover, the M first candidate cells are valid first candidate cells, and all or part of configuration information of the first candidate cells may be reserved for the subsequent first handover, thereby improving the success rate of the first handover. Alternatively, the configuration information of the configured or indicated first candidate cell for the subsequent first handover may be retained, i.e. the configuration information of the first candidate cell associated with the target cell of the second handover is retained. Otherwise, if the target cell of the second handover is not the first candidate cell of the M first candidate cells, the invalid information is prevented from being stored by releasing the configuration information of the first candidate cells, so that the memory occupation is reduced, and the handover success rate is improved.

The following is an example.

In one example, the current serving cell of the UE is cell 1, and configuration information of 4 first candidate cells configured by the base station is received, where the 4 first candidate cells include cells 2 to 5. After that, the UE performs a second handover from cell 1 to cell 2. Since the target cell (cell 2) of the second handover is one of the 4 first candidate cells, configuration information of all 4 first candidate cells can be retained.

In another example, the current serving cell of the UE is cell 1 and the base station configures a first candidate cell comprising cell 2-cell 10. The base station also indicates that when the UE is handed over to cell 2, the first candidate cell for the first handover of the UE in cell 2 comprises cell 2-cell 8, the first candidate cell for the first handover of the UE in cell 3 comprises cell 2-cell 6, and the first candidate cell for the first handover of the UE in cell 4 comprises cell 5-cell 10. Suppose that the UE performs a second handover from cell 1 to cell 2. Cell 2 is one of the first candidate cells (cell 2-cell 10) of cell 1.

Alternatively, in one implementation, after the UE successfully switches to cell 2, all M first candidate cells, namely cell 2-cell 10, may be reserved.

Alternatively, in another implementation, after the UE successfully switches to cell 2, configuration information of a first candidate cell related to the target cell of the second handover, that is, a first candidate cell (cell 2-cell 8) configured by the network for cell 2 before, may be retained. Alternatively, the first candidate cell configuration of cell 1 may also be reserved.

Example IV

On the basis of the embodiment shown in fig. 7, a handoff method provided in another embodiment of the present application provides an implementation manner of S704. Alternatively, the scenario shown in FIG. 5 for L3 HO and L1/L2 HO support, and the scenario shown in FIG. 6 for L3 CHO and L1/L2 HO support are applicable. In this embodiment, it is predefined that the terminal device successfully completes the second handover, and releases configuration information of all M first candidate cells. The implementation mode is simple.

In S704, the terminal device performs a first operation including:

the terminal device releases the configuration information of all the first candidate cells in the M first candidate cells.

Example five

Optionally, in another embodiment of the present application, on the basis of the foregoing embodiment, a specific implementation manner of S704 is provided for the scenario supporting L3 HO and L1/L2 HO shown in fig. 5.

In this embodiment, the first handover is an L1/L2 HO, and the M first candidate cells are M L1/L2 HO candidate cells. The second handover is L3 HO. Illustratively, as shown in fig. 5, the first message is an RRC reconfiguration message in step 405. The second message is the RRC reconfiguration message in step 207, where the second message includes a handover command. Alternatively, the first message and the second message may be other RRC reconfiguration messages, or other RRC messages, other than steps 405 and 207.

In the present embodiment, it is assumed that m=10, and 10 first candidate cells include: L1/L2 HO candidate cells 1 to L1/L2 HO candidate cell 10.

1. Embodiment one

The implementation manner of the fourth embodiment of the present application is adopted. See the relevant description.

Specifically, in the scenario supporting L3 HO and L1/L2 HO shown in fig. 5, in S704, the second handover is successfully completed, and the terminal device executes a first operation, including:

the UE executes L3 HO and releases configuration information of all L1/L2 HO candidate cells in the M L1/L2 HO candidate cells; or,

the UE sends a switching completion message, and releases configuration information of all L1/L2 HO candidate cells in the M L1/L2 HO candidate cells; or,

the UE completes the random access to the target cell of the L3 HO and releases the configuration information of all L1/L2 HO candidate cells in the M L1/L2 HO candidate cells.

Illustratively, in fig. 5, the handover complete message is the RRC reconfiguration complete message in step 211.

In this embodiment, the UE successfully completes L3 HO and releases configuration information of all L1/L2 HO candidate cells according to a predetermined rule. The implementation mode is simple, and the memory occupation is reduced.

2. Second embodiment

The first implementation manner of the indication information in the second embodiment of the present application is adopted. See the relevant description.

Specifically, in the scenario supporting L3 HO and L1/L2 HO shown in fig. 5, the RRC reconfiguration message in step 207 includes indication information. The indication information is 1-bit indication information.

In S704, the terminal device performs a first operation, including:

and the UE reserves or releases or does not reserve or does not release the configuration information of all L1/L2 HO candidate cells in the M L1/L2 HO candidate cells according to the 1-bit indication information.

For example.

Assuming that the indication information is 1, the ue releases or does not reserve configuration information of the L1/L2 HO candidate cells 1 to L1/L2 HO candidate cell 10. The indication information is 0, and the UE reserves or does not release the configuration information of the L1/L2 HO candidate cells 1-L1/L2 HO candidate cell 10.

In the embodiment, the base station determines whether to release the configuration of the L1/L2 HO candidate cell, thereby ensuring the accuracy of configuration and improving the success rate of switching. The UE may reserve or release configuration information of all M L1/L2 HO candidate cells according to the 1-bit indication information configured by the base station. The indication information is only 1 bit, the indication mode is simple, and the signaling overhead is saved.

3. Embodiment III

A third implementation manner of the indication information in the second embodiment of the present application is adopted. See the relevant description.

Specifically, in the scenario supporting L3 HO and L1/L2 HO shown in fig. 5, the RRC reconfiguration message includes indication information, and optionally, the RRC reconfiguration message is the RRC reconfiguration message in step 207. The indication information includes a configuration identification of the at least one cell, the configuration identification being associated with configuration information of the at least one L1/L2 HO candidate cell.

In S704, the terminal device performs a first operation, including:

and the UE reserves the configuration information of at least one L1/L2 HO candidate cell associated with the configuration identifier in the M L1/L2 HO candidate cells according to the configuration identifier of the at least one cell, and releases the configuration information of other L1/L2 HO candidate cells which are not associated with the configuration identifier in the M L1/L2 HO candidate cells. Or,

and the UE releases the configuration information of at least one L1/L2 HO candidate cell associated with the configuration identifier in the M L1/L2 HO candidate cells according to the configuration identifier of the at least one cell, and reserves the configuration information of other L1/L2 HO candidate cells which are not associated with the configuration identifier in the M L1/L2 HO candidate cells.

In the embodiment, the base station determines whether to release the configuration of the L1/L2 HO candidate cell, thereby ensuring the accuracy of configuration and improving the success rate of switching. The UE can reserve or release configuration information of at least one L1/L2 HO candidate cell in the M L1/L2 HO candidate cells according to the configuration identification of at least one cell configured by the base station, and the indication mode is flexible.

4. Fourth embodiment

A fourth implementation manner of the indication information in the second embodiment of the present application is adopted. See the relevant description.

Specifically, in the scenario supporting L3 HO and L1/L2 HO shown in fig. 5, the RRC reconfiguration message in step 207 includes indication information. The indication information is second bit mapping indication information, the second bit mapping indication information indicates K L1/L2 HO candidate cells in M L1/L2 HO candidate cells to be associated with 1 bit indication information, and K is a positive integer less than or equal to M.

In S704, the terminal device performs a first operation, including:

and the terminal equipment reserves or releases the configuration information of the K L1/L2 HO candidate cells according to the 1-bit indication information respectively associated with the K L1/L2 HO candidate cells.

Optionally, the terminal device reserves configuration information of other L1/L2 HO candidate cells, where the second bitmap indication information is not associated with the other L1/L2 HO candidate cells.

Optionally, the terminal device releases configuration information of other L1/L2 HO candidate cells, where the second bitmap indication information is not associated with the other L1/L2 HO candidate cells.

In the embodiment, the base station determines whether to release the configuration of the L1/L2 HO candidate cell, thereby ensuring the accuracy of configuration and improving the success rate of switching. The UE can reserve or release configuration information of at least one L1/L2 HO candidate cell in the M L1/L2 HO candidate cells according to the second bit mapping indication information configured by the base station, and the indication mode is flexible.

5. Fifth embodiment

With the fifth implementation manner of the indication information in the second embodiment of the present application, reference may be made to the related description.

Specifically, in the scenario supporting L3 HO and L1/L2 HO shown in fig. 5, the RRC reconfiguration message in step 207 includes indication information. The indication information includes reconfiguration information of at least one L1/L2 HO candidate cell.

In the embodiment, the base station determines whether to release or reconfigure the configuration of the L1/L2 HO candidate cell, thereby ensuring the accuracy of configuration and improving the success rate of switching. The UE can reserve or release the stored configuration information of at least one L1/L2 HO candidate cell in M L1/L2 HO candidate cells according to the reconfiguration information of the L1/L2 HO candidate cells configured by the base station, and can also newly add the configuration information of the L1/L2 HO candidate cells, so that the indication mode is flexible.

6. Embodiment six

With the implementation manner of the foregoing embodiment three of the present application, reference may be made to the related description.

In this embodiment, the UE reserves or releases configuration information of all M L1/L2 HO candidate cells according to the target cell of the L3 HO, or reserves configuration information of L1/L2 HO candidate cells associated with the target cell of the L3 HO among the M L1/L2 HO candidate cells. Because the UE determines the configuration mode of processing the L1/L2 HO candidate cells, the base station is not required to send indication information, the air interface signaling overhead is saved, and the implementation mode is flexible.

Example six

Alternatively, in yet another embodiment of the present application, on the basis of the above embodiment, a specific implementation manner of S704 is provided for the scenario supporting L3 CHO and L1/L2 HO shown in fig. 6.

In this embodiment, the first handover is an L1/L2 HO, and the M first candidate cells are M L1/L2 HO candidate cells. The second handover is L3 CHO, and the N second candidate cells are N L3 CHO candidate cells. As shown in fig. 6, the first message is an RRC reconfiguration message in step 405. The second message is the RRC reconfiguration message in step 306. Alternatively, the first message and the second message may be other RRC reconfiguration messages, or other RRC messages, other than steps 405 and 207.

In the present embodiment, it is assumed that m=10, and 10 first candidate cells include: L1/L2 HO candidate cells 1 to L1/L2 HO candidate cell 10. N=3, the 3 second candidate cells include: l3 CHO candidate cell 1 to L3 CHO candidate cell 3.

The scenario supporting L3 CHO and L1/L2 HO shown in fig. 6 differs from the scenario supporting L3 HO and L1/L2 HO shown in fig. 5 in that:

in fig. 5, the base station determines a target cell for the L3 HO and indicates to the UE through a handover command. If the continuity of the subsequent L1/L2 HO is considered, only configuration information of M L1/L2 HO candidate cells needs to be processed for one cell of the target cell of the L3 HO.

In fig. 6, the base station configures N L3 CHO candidate cells for the UE, and each L3 CHO candidate cell is likely to be the target cell of L3 CHO. Considering the continuity of the subsequent L1/L2 HO, in some embodiments, different ways of processing the L1/L2 HO candidate cells may be adopted for different L3 CHO candidate cells, so as to further improve the accuracy of configuration and improve the handover success rate. For example, for L3 CHO candidate cell 1, configuration information of all 10L 1/L2 HO candidate cells is reserved. For L3 CHO candidate cell 2, only configuration information of 5L 1/L2 HO candidate cells out of 10 is reserved.

In the scenario supporting L3 CHO and L1/L2 HO shown in fig. 6, in some embodiments, the L3 CHO candidate cells may not be differentiated, and the same processing manner for the configuration information of the M L1/L2 HO candidate cells may be adopted for the N L3 CHO candidate cells.

1. Embodiment one

Specifically, in the scenario supporting L3 CHO and L1/L2 HO shown in fig. 6, in S704, the second handover is successfully completed, and the terminal device executes a first operation, including:

the UE executes L3 CHO, and releases configuration information of all L1/L2 HO candidate cells in the M L1/L2 HO candidate cells; or,

the UE completes the random access to the target cell of the L3 CHO, and releases the configuration information of all L1/L2 HO candidate cells in the M L1/L2 HO candidate cells.

For example, in this embodiment, after CHO is successful, the UE sends an RRC reconfiguration complete message to the target base station. Not shown in fig. 6, see the associated description of step 308 of fig. 3.

In the present embodiment, the UE successfully completes L3 CHO and releases configuration information of all L1/L2 HO candidate cells according to a predetermined rule. The implementation mode is simple, and the memory occupation is reduced.

2. Second embodiment

Specifically, in the scenario supporting L3 CHO and L1/L2 HO shown in fig. 6, the RRC reconfiguration message in step 306 includes indication information. The indication information is 1-bit indication information.

In S704, the terminal device performs a first operation, including:

For example.

Assuming that the indication information takes a value of 1, the ue releases or does not retain the configuration information of the L1/L2 HO candidate cells 1 to L1/L2 HO candidate cell 10 for the L3 CHO candidate cells 1 to L3 CHO candidate cell 3. The indication information takes a value of 0, and for the L3 CHO candidate cells 1-L3 CHO candidate cell 3, the UE keeps or does not release the configuration information of the L1/L2 HO candidate cells 1-L1/L2 HO candidate cell 10.

In the embodiment, the base station determines whether to release the configuration of the L1/L2 HO candidate cell, thereby ensuring the accuracy of configuration and improving the success rate of switching. And the UE keeps or releases configuration information of all M L1/L2 HO candidate cells according to the 1-bit indication information configured by the base station without distinguishing the L3 CHO candidate cells. The indication information is only 1 bit, the indication mode is simple, and the signaling overhead is saved.

3. Embodiment III

Wherein, any one second candidate cell in the N second candidate cells is associated with 1 bit of indication information.

The present embodiment differs from the second embodiment in that:

in the second embodiment, the L3 CHO candidate cell is not distinguished, and the indication information includes 1-bit indication information.

In the present embodiment, L3 CHO candidate cells are distinguished, and each L3 CHO candidate cell is associated with 1-bit indication information, and the indication information includes N1-bit indication information. In this way, configuration information of all M L1/L2 HO candidate cells can be reserved or released for different L3 CHO candidate cells.

Specifically, in the scenario supporting L3 CHO and L1/L2 HO shown in fig. 6, the RRC reconfiguration message in step 306 includes indication information. In the indication information, any one L3 CHO candidate cell of the N L3 CHO candidate cells is associated with 1-bit indication information.

For example.

The L3 CHO candidate cell 1 associated 1 bit indicates that the information is 1. For L3 CHO candidate cell 1, the UE releases or does not retain configuration information of L1/L2 HO candidate cells 1-L1/L2 HO candidate cell 10.

The L3 CHO candidate cell 2 associated 1-bit indication information is 1. For L3 CHO candidate cell 2, the UE releases or does not retain configuration information of L1/L2 HO candidate cells 1-L1/L2 HO candidate cell 10.

The L3 CHO candidate cell 3 associated 1-bit indication information is 0. For L3 CHO candidate cell 3, the UE reserves or does not release configuration information of L1/L2 HO candidate cells 1-L1/L2 HO candidate cell 10.

4. Fourth embodiment

A second implementation manner of the indication information in the second embodiment of the present application is adopted. See the relevant description.

The present embodiment is the same as the third embodiment in that: configuration information of all M L1/L2 HO candidate cells can be reserved or released for different L3 CHO candidate cells.

The present embodiment differs from the third embodiment in that: in the third embodiment, the instruction information includes N pieces of 1-bit instruction information, and any one L3 CHO candidate cell is associated with 1-bit instruction information. In the present embodiment, the indication information includes a first bit map indication information, and all or part of the N L3 CHO candidate cells correspond to 1 bit indication information by means of bit map.

Specifically, in the scenario supporting L3 CHO and L1/L2 HO shown in fig. 6, the RRC reconfiguration message in step 306 includes indication information. The indication information is first bit mapping indication information, the first bit mapping indication information indicates that S L3 CHO candidate cells in N L3 CHO candidate cells are associated with 1 bit indication information, and S is a positive integer less than or equal to N.

5. Fifth embodiment

Specifically, in the scenario supporting L3 CHO and L1/L2 HO shown in fig. 6, the RRC reconfiguration message in step 306 includes indication information. The indication information includes a configuration identification of the at least one cell, the configuration identification being associated with configuration information of the at least one L1/L2 HO candidate cell.

Optionally, in one implementation, for each CHO candidate cell, the same processing manner is adopted for the configuration information of the M L1/L2 HO candidate cells according to the configuration identifier of at least one cell in the indication information.

For example.

The configuration identity is a cell ID. The cell IDs of the L1/L2 HO candidate cells 1 to L1/L2 HO candidate cell 10 are 1 to 10, respectively. It is assumed that the indication information includes cell IDs of 3 cells, respectively 2 to 5, corresponding to L1/L2 HO candidate cells 2 to 5.

For each L3 CHO candidate cell in L3 CHO candidate cells 1-L3 CHO candidate cell 3, UE reserves configuration information of L1/L2 HO candidate cells 2-5.

Alternatively, in another implementation, the configuration information of M L1/L2 HO candidate cells is processed separately by different CHO candidate cells. At this time, the indication information may include T groups of configuration identifications, each group of configuration identifications including a configuration identification of at least one cell, the configuration identification of the at least one cell being associated with configuration information of at least one L1/L2 HO candidate cell. The T group configuration identity is associated with T L3 CHO candidate cells of the N L3 CHO candidate cells. T is a positive integer less than or equal to N.

Optionally, N > T, and there is an L3 CHO candidate cell of the N L3 CHO candidate cells other than the T L3 CHO candidate cells for which no configuration identifier is associated. For the L3 CHO candidate cells with no associated configuration identification, the UE releases the configuration information of all M L1/L2 HO candidate cells, or reserves the configuration information of all M L1/L2 HO candidate cells.

For example.

The configuration identity is a cell ID. The cell IDs of the L1/L2 HO candidate cells 1 to L1/L2 HO candidate cell 10 are 1 to 10, respectively. Assuming that the indication information comprises 1 group of configuration identifiers, the value is 2-5, and the indication information corresponds to L1/L2 HO candidate cells 2-5. The set of configuration identities associates L3 CHO candidate cell 1.

Then, for L3 CHO candidate cell 1, the UE retains configuration information of L1/L2 HO candidate cells 2-5.

For L3 CHO candidate cell 2 and L3 CHO candidate cell 3, UE releases configuration information of L1/L2 HO candidate cells 1-10.

6. Embodiment six

Specifically, in the scenario supporting L3 CHO and L1/L2 HO shown in fig. 6, the RRC reconfiguration message in step 306 includes indication information. The indication information is second bit mapping indication information, the second bit mapping indication information indicates K L1/L2 HO candidate cells in M L1/L2 HO candidate cells to be associated with 1 bit indication information, and K is a positive integer less than or equal to M.

In this embodiment, for each L3 CHO candidate cell, configuration information of at least one L1/L2 HO candidate cell of the M L1/L2 HO candidate cells is reserved or released according to the second bitmap indication information, and the indication manner is flexible.

For example.

Assume that the 1-bit indication information takes a value of 0, indicating that configuration information of a corresponding L1/L2 HO candidate cell is reserved. The 1 bit indication information takes a value of 1 and indicates to release the configuration information of the corresponding L1/L2 HO candidate cell.

The second bit map indication information may have a binary 1111100000 value. Then, for each L3 CHO candidate cell in L3 CHO candidate cells 1-L3 CHO candidate cell 3, releasing configuration information of L1/L2 HO candidate cells 1-L1/L2 HO candidate cell 5, and reserving configuration information of L1/L2 HO candidate cells 6-L1/L2 HO candidate cell 10.

7. Embodiment seven

Wherein, any one of the N second candidate cells is associated with second bit mapping indication information.

The present embodiment differs from the sixth embodiment in that:

in the sixth embodiment, the L3 CHO candidate cells are not distinguished, and the indication information includes 1 second bit map indication information. It can be understood that N L3 CHO candidate cells are associated with the same second bitmap indication information.

In the present embodiment, the L3 CHO candidate cells are distinguished, and the indication information includes N pieces of second bitmap indication information. Each L3 CHO candidate cell is associated with a second bitmap indication. In this way, configuration information of all M L1/L2 HO candidate cells can be reserved or released for different L3 CHO candidate cells.

Specifically, in the scenario supporting L3 CHO and L1/L2 HO shown in fig. 6, the RRC reconfiguration message in step 306 includes indication information. The indication information includes second bit map indication information, the second bit map indication information indicates that K L1/L2 HO candidate cells among the M L1/L2 HO candidate cells are associated with 1 bit indication information, and K is a positive integer less than or equal to M. And associating the second bit mapping indication information with any L3 CHO candidate cell in the N L3 CHO candidate cells.

For example.

The value of the second bit map indication information associated with the L3 CHO candidate cell 1 may be binary 1111100000. Then, for the L3 CHO candidate cell 1, releasing the configuration information of the L1/L2 HO candidate cells 1-L1/L2 HO candidate cell 5, and reserving the configuration information of the L1/L2 HO candidate cells 6-L1/L2 HO candidate cell 10.

The value of the second bitmap indication information associated with the L3 CHO candidate cell 2 may be binary 0000011111. Then, for the L3 CHO candidate cell 2, releasing the configuration information of the L1/L2 HO candidate cells 6-L1/L2 HO candidate cell 10, and reserving the configuration information of the L1/L2 HO candidate cells 1-L1/L2 HO candidate cell 5.

The value of the second bitmap indication information associated with the L3 CHO candidate cell 2 may be binary 0001110000. Then, for the L3 CHO candidate cell 2, releasing the configuration information of the L1/L2 HO candidate cells 4-L1/L2 HO candidate cell 6, and reserving the configuration information of the L1/L2 HO candidate cells 1-L1/L2 HO candidate cell 3 and the L1/L2 HO candidate cells 7-L1/L2 HO candidate cell 10.

8. Embodiment eight.

Specifically, in the scenario supporting L3 CHO and L1/L2 HO shown in fig. 6, the RRC reconfiguration message in step 306 includes indication information. The indication information includes reconfiguration information of at least one L1/L2 HO candidate cell.

In the embodiment, the base station determines whether to release or reconfigure the configuration of the L1/L2 HO candidate cell, thereby ensuring the accuracy of configuration and improving the success rate of switching. The UE can reserve or release the stored configuration information of at least one L1/L2 HO candidate cell in M L1/L2 HO candidate cells according to the reconfiguration information of the L1/L2 HO candidate cells configured by the base station, can newly add the configuration information of the L1/L2 HO candidate cell, can update the configuration information of at least one L1/L2 HO candidate cell in the M L1/L2 HO candidate cells configured currently, and has flexible indication mode.

9. Embodiment nine.

In this embodiment, the UE reserves or releases configuration information of all M L1/L2 HO candidate cells according to the target cell of L3 CHO, or reserves configuration information of L1/L2 HO candidate cells associated with the target cell of L3 CHO among the M L1/L2 HO candidate cells. Because the UE determines the configuration mode of processing the L1/L2 HO candidate cells, the base station is not required to send indication information, the air interface signaling overhead is saved, and the implementation mode is flexible.

Example seven

In yet another embodiment of the present application, a handover method is provided. Exemplary, applicable application scenarios are: the base station configures N L3 CHO candidate cells and M L1/L2 HO candidate cells for the UE, and the UE receives configuration information of the N L3 CHO candidate cells from the network equipment, wherein the configuration information comprises CHO execution conditions and the configuration information of the M L1/L2 HO candidate cells. N and M are positive integers.

Optionally, in one implementation, the switching method includes:

the UE evaluates CHO execution conditions of N L3 CHO candidate cells to determine a target cell of L3 CHO.

If the target cell of the L3 CHO is one L1/L2 HO candidate cell of M L1/L2 HO candidate cells, the UE executes the L1/L2 HO according to the configuration information of the L1/L2 HO candidate cell associated with the target cell of the L3 CHO.

The interruption of the service is reduced because the access delay of the L1/L2 HO is shorter.

Optionally, in another implementation, the switching method includes:

and in the process that the UE evaluates whether the CHO execution conditions of the N L3 CHO candidate cells are met or not, receiving a L1/L2 HO switching command.

The UE performs L1/L2 HO and stops evaluating CHO execution conditions of N L3 CHO candidate cells.

Because the access time delay of the L1/L2 HO is shorter, the L1/L2 HO is preferentially executed, and the interruption of the service is reduced.

Optionally, the switching method further includes:

the L1/L2 HO is successfully completed, and the UE releases the configuration information and CHO execution conditions of the N L3 CHO candidate cells.

In the implementation mode, after the UE successfully executes the L1/L2 HO, the configuration of the L3 CHO candidate cell is released in time, so that the memory occupation is avoided, and the switching success rate is improved.

Optionally, the switching method further includes:

the L1/L2 HO fails and the UE performs RRC reestablishment.

The target cell selected by RRC reestablishment is one L3 CHO candidate cell in N L3 CHO candidate cells, and UE uses the CHO related configuration related to the target cell to execute the L3 CHO process; or,

the RRC reestablishment selects a target cell which is one L1/L2 HO candidate cell in M L1/L2 HO candidate cells, and the UE uses the L1/L2 HO related configuration associated with the target cell to execute an L1/L2 HO process; or,

the target cell selected by the RRC reestablishment is one L3 CHO candidate cell in N L3 CHO candidate cells and is also one L1/L2 HO candidate cell in M L1/L2 HO candidate cells, and the UE executes L1/L2 HO by using the configuration related to L1/L2 HO associated with the target cell.

In this implementation, the UE fails to perform L1/L2 HO, and the original procedure is to perform RRC reestablishment. If the target cell of the RRC re-establishment is an L3 CHO candidate cell, L3 CHO is preferentially performed. If the target cell for RRC re-establishment is an L1/L2 HO candidate cell, L1/L2 HO is preferentially performed. If the target cell for RRC re-establishment is both an L3 CHO candidate cell and an L1/L2 HO candidate cell, L1/L2 HO is preferentially performed. If the above condition is not satisfied, RRC reestablishment may be performed.

By preferentially executing L3CHO or L1/L2 HO, the interruption of service is reduced, and the handover process is completed more quickly.

Optionally, in yet another implementation, the switching method includes:

the UE handover fails and the UE performs RRC reestablishment.

The target cell selected by RRC reestablishment is one L3CHO candidate cell in N L3CHO candidate cells, and then L3CHO is executed; or,

the RRC reestablishment selects a target cell which is one L1/L2 HO candidate cell in M L1/L2 HO candidate cells, and then L1/L2 HO is executed; or,

the target cell selected by the RRC reestablishment is one L3CHO candidate cell of N L3CHO candidate cells and is also one L1/L2 HO candidate cell of M L1/L2 HO candidate cells, and the UE executes L1/L2 HO.

Optionally, the UE handover failure may include:

the UE fails to perform L3 HO, or the UE fails to perform L3CHO, or the UE fails to perform L1/L2 HO.

In this implementation, the UE fails to perform any handover, and the original procedure is to perform RRC reestablishment. However, if the target cell for RRC re-establishment is the L3CHO candidate cell or the L1/L2 HO candidate cell, the interruption of the service is reduced by preferentially performing L3CHO or L1/L2 HO.

In the embodiments provided in the present application, the method provided in the embodiments of the present application is described from the perspective of the network device, the terminal device, and the interaction between the network device and the terminal device, respectively. In order to implement the functions in the methods provided in the embodiments of the present application, the network device and the terminal device may include hardware structures and/or software modules, and implement the functions in the form of hardware structures, software modules, or a combination of hardware structures and software modules. Some of the functions described above are performed in a hardware configuration, a software module, or a combination of hardware and software modules, depending on the specific application of the solution and design constraints.

Fig. 8 is a schematic structural diagram of a possible communication device according to an embodiment of the present application. These communication devices can implement the functions of the terminal device or the network device in the above method embodiment, so that the beneficial effects of the above method embodiment can also be implemented. In this embodiment of the present application, the communication device may be a terminal device 101 as shown in fig. 1, or may be a network device 102 as shown in fig. 1, or may be a module (such as a chip) applied to a terminal device or an access network device.

As shown in fig. 8, the communication device 800 includes a transceiver module 801 and a processing module 802. The communication apparatus 800 may be used to implement the functions of the terminal device or the network device in the method embodiments described in the first to seventh embodiments.

When the communication device 800 is used to implement the functions of the terminal device in the embodiment of the method described in fig. 7: a transceiver module 801, configured to receive a first message from a network device, where the first message includes configuration information of M first candidate cells for the first handover, and M is a positive integer; the transceiver module 801 is further configured to receive a second message from the network device, where the second message includes configuration information of the target cell of the second handover. A processing module 802, configured to perform a second handover according to the second message; the second switching is successfully completed, and the first operation is executed; the first operation includes reserving, releasing, or reconfiguring configuration information of the M first candidate cells.

When the communication apparatus 800 is used to implement the functions of the network device in the embodiment of the method described in fig. 7: a transceiver module 801, configured to send a first message to a terminal device, where the first message includes configuration information of M first candidate cells for the first handover, and M is a positive integer; the transceiver module 801 is further configured to send a second message to the terminal device, where the second message includes configuration information of the target cell of the second handover and indication information, and the indication information indicates to reserve, release, or reconfigure configuration information of all of the M first candidate cells or at least one of the M first candidate cells.

For a more detailed description of the transceiver module 801 and the processing module 802, reference is made to the relevant description of the method embodiments described above, which are not further described herein.

Fig. 9 shows a simplified schematic diagram of the terminal device when the communication device is a terminal device. The terminal device is illustrated as a mobile phone in fig. 9 for easy understanding and convenient illustration. As shown in fig. 9, the terminal device includes a processor, a memory, a radio frequency circuit, an antenna, and an input-output device. The processor is mainly used for processing communication protocols and communication data, controlling the terminal equipment, executing software programs, processing data of the software programs and the like. The memory is mainly used for storing software programs and data. The radio frequency circuit is mainly used for converting a baseband signal and a radio frequency signal and processing the radio frequency signal. The antenna is mainly used for receiving and transmitting radio frequency signals in the form of electromagnetic waves. Input and output devices, such as touch screens, display screens, keyboards, etc., are mainly used for receiving data input by a user and outputting data to the user. It should be noted that some kinds of terminal apparatuses may not have an input/output device.

When data need to be sent, the processor carries out baseband processing on the data to be sent and then outputs a baseband signal to the radio frequency circuit, and the radio frequency circuit carries out radio frequency processing on the baseband signal and then sends the radio frequency signal outwards in the form of electromagnetic waves through the antenna. When data is sent to the terminal equipment, the radio frequency circuit receives a radio frequency signal through the antenna, converts the radio frequency signal into a baseband signal, and outputs the baseband signal to the processor, and the processor converts the baseband signal into data and processes the data. For ease of illustration, only one memory and processor is shown in fig. 9. In an actual end device product, there may be one or more processors and one or more memories. The memory may also be referred to as a storage medium or storage device, etc. The memory may be provided separately from the processor or may be integrated with the processor, which is not limited by the embodiments of the present application.

In the embodiment of the present application, the antenna and the radio frequency circuit with the transmitting and receiving functions may be regarded as a transmitting and receiving unit of the terminal device (the transmitting and receiving unit may be one functional unit, which can implement the transmitting function and the receiving function, or the transmitting and receiving unit may also include two functional units, which are a receiving unit capable of implementing the receiving function and a transmitting unit capable of implementing the transmitting function, respectively), and the processor with the processing function may be regarded as a processing unit of the terminal device. As shown in fig. 9, the terminal device includes a transceiving unit 2310 and a processing unit 2320. The transceiver unit may also be referred to as a transceiver, transceiver device, etc. The processing unit may also be called a processor, a processing board, a processing module, a processing device, etc. Alternatively, the device for implementing the receiving function in the transceiver unit 2310 may be regarded as a receiving unit, and the device for implementing the transmitting function in the transceiver unit 2310 may be regarded as a transmitting unit, that is, the transceiver unit 2310 includes a receiving unit and a transmitting unit. The transceiver unit may also be referred to as a transceiver, transceiver circuitry, or the like. The receiving unit may also be referred to as a receiver, or receiving circuit, among others. The transmitting unit may also sometimes be referred to as a transmitter, or a transmitting circuit, etc.

It should be understood that, the transceiver 2310 is configured to perform the transmitting operation and the receiving operation of the terminal device in the above method embodiment, and the processing unit 2320 is configured to perform other operations on the terminal device except for the transmitting operation in the above method embodiment.

Illustratively, the processing unit 2320 may perform actions similar to those performed by the processing module 2110, or the processing module 2320 includes the processing module 2110. Transceiver unit 2310 may perform actions similar to those performed by transceiver module 2120, or transceiver unit 2310 includes transceiver module 2120.

When the communication device is a chip-like device or circuit, the device may comprise a transceiver unit and a processing unit. The transceiver unit may be an input-output circuit and/or a communication interface; the processing unit is an integrated processor or microprocessor or integrated circuit.

When the apparatus in the embodiment of the present application is a network device, the apparatus may be as shown in fig. 10. The apparatus may include one or more radio frequency units, such as a remote radio frequency unit (remote radio unit, RRU) 2410 and one or more baseband units (BBU) (also referred to as digital units, DUs) 2420. The RRU 2410 may be referred to as a transceiver module, which may include a transmitting module and a receiving module, or the transceiver module may be a module capable of implementing transmitting and receiving functions. Alternatively, the transceiver module may also be referred to as a transceiver, transceiver circuitry, or transceiver, etc., which may include at least one antenna 2411 and a radio frequency unit 2412. The RRU 2410 is mainly used for receiving and transmitting radio frequency signals and converting radio frequency signals and baseband signals. The BBU 2410 portion is mainly used for baseband processing, control of a base station, and the like. The RRU 2410 and BBU 2420 may be physically located together or physically separate, i.e., distributed base stations.

The BBU 2420 is a control center of the base station, and may also be referred to as a processing module, and is mainly configured to perform baseband processing functions, such as channel coding, multiplexing, modulation, spreading, and so on. For example, the BBU (processing module) may be configured to control the base station to perform the operation procedures described in the above method embodiments with respect to the network device.

In one example, the BBU 2420 may be formed of one or more single boards, and the multiple single boards may support radio access networks of a single access system (such as an LTE network) together, or may support radio access networks of different access systems (such as an LTE network, a 5G network, or other networks) respectively. The BBU 2420 further comprises a memory 2421 and a processor 2422. The memory 2421 is used to store necessary instructions and data. The processor 2422 is configured to control the base station to perform the necessary actions, for example, to control the base station to perform the operation procedure of the above method embodiment with respect to the network device. The memory 2421 and processor 2422 may serve one or more boards. That is, the memory and the processor may be separately provided on each board. It is also possible that multiple boards share the same memory and processor. In addition, each single board can be provided with necessary circuits.

The embodiment of the application provides a communication system. The communication system may comprise the terminal device and the network device as referred to in the above-described embodiment shown in fig. 1. Optionally, the terminal device and the network device in the communication system may execute the handover method provided by the embodiment of the method of the present application.

The present application further provides a computer readable storage medium, where a computer program is stored, where the computer program when executed by a computer may implement a procedure related to a terminal device or a network device in any of the embodiments of the method described above.

The embodiments of the present application further provide a computer program product, where the computer program product is configured to store a computer program, where the computer program when executed by a computer may implement a procedure related to a terminal device or a network device in any of the embodiments of the method described above.

The present application further provides a chip or a chip system, where the chip may include a processor, and the processor may be configured to invoke a program or an instruction in a memory to execute a procedure related to a terminal device or a network device in any of the embodiments of the method described above. The chip system may include the chip, and may also include other components such as a memory or transceiver.

Embodiments of the present application also provide a circuit, which may be coupled to a memory, and may be used to perform a procedure associated with a terminal device or a network device in any of the embodiments of the method described above. The chip system may include the chip, and may also include other components such as a memory or transceiver.

It should be appreciated that the processors referred to in the embodiments of the present application may be CPUs, but may also be other general purpose processors, digital signal processors (digital signal processor, DSPs), application specific integrated circuits (application specific integrated circuit, ASICs), off-the-shelf programmable gate arrays (field programmable gate array, FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

It should also be understood that the memory referred to in the embodiments of the present application may be volatile memory or nonvolatile memory, or may include both volatile and nonvolatile memory. The nonvolatile memory may be a read-only memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an electrically Erasable EPROM (EEPROM), or a flash memory. The volatile memory may be random access memory (random access memory, RAM) which acts as an external cache. By way of example, and not limitation, many forms of RAM are available, such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous DRAM (SLDRAM), and direct memory bus RAM (DR RAM).

Note that when the processor is a general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware components, the memory (storage module) is integrated into the processor.

It should be noted that the memory described herein is intended to comprise, without being limited to, these and any other suitable types of memory.

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

Those of ordinary skill in the art will appreciate that the various illustrative modules and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It will be clearly understood by those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described system, apparatus and module may refer to corresponding procedures in the foregoing method embodiments, which are not repeated herein.

In the several embodiments provided in the present application, it should be understood that the disclosed switching method and apparatus may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, and for example, the division of the modules is merely a logical function division, and there may be additional divisions when actually implemented, for example, multiple modules or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.

The modules illustrated as separate components may or may not be physically separate, and components shown as modules may or may not be physical modules, i.e., may be located in one place, or may be distributed over a plurality of network elements. 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 module in each embodiment of the present application may be integrated into one processing module, or each module may exist alone physically, or two or more modules may be integrated into one module.

The functions, if implemented in the form of software functional modules and sold or used as a stand-alone product, may be stored on a computer readable storage medium. Based on such understanding, the technical solution of the present application may be embodied in essence or contributing part or part of the technical solution in the form of a software product stored in a storage medium, including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method of the embodiments of the present application. The foregoing computer-readable storage media can be any available media that can be accessed by a computer. Taking this as an example but not limited to: the computer readable medium may include random access memory (random access memory, RAM), read-only memory (ROM), electrically erasable programmable read-only memory (electrically erasable programmable read only memory, EEPROM), compact disk read-only memory (CD-ROM), universal serial bus flash disk (universal serial bus flash disk), removable hard disk, or other optical disk storage, magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer.

The network architecture and the service scenario described in the embodiments of the present application are for more clearly describing the technical solution of the embodiments of the present application, and do not constitute a limitation on the technical solution provided in the embodiments of the present application, and those skilled in the art can know that, with the evolution of the network architecture and the appearance of the new service scenario, the technical solution provided in the embodiments of the present application is also applicable to similar technical problems.

The foregoing is merely specific embodiments of the present application, but the scope of the embodiments of the present application is not limited thereto, and any person skilled in the art may easily think about changes or substitutions within the technical scope disclosed in the embodiments of the present application, and all changes and substitutions are included in the scope of the embodiments of the present application. Therefore, the protection scope of the embodiments of the present application shall be subject to the protection scope of the claims.

Claims

1. A method of handover, comprising:

the terminal equipment receives a first message from the network equipment; the first message comprises configuration information of M first candidate cells switched by a first switch, wherein M is a positive integer;

the terminal equipment receives a second message from the network equipment; the second message comprises configuration information of a target cell of the second handover;

The terminal equipment executes the second switching according to the second message;

the second switching is successfully completed, and the terminal equipment executes a first operation; the first operation includes reserving, releasing, or reconfiguring configuration information of the M first candidate cells.

2. The method of claim 1, wherein the second message further comprises indication information indicating that configuration information of all of the M first candidate cells or at least one of the M first candidate cells is reserved, released, or reconfigured;

the terminal device performs a first operation, including:

3. The method of claim 2, wherein the indication information is 1-bit indication information; or, the indication information is first bit mapping indication information.

4. The method of claim 3, wherein the second handover is a conditional handover, the second message including configuration information of N second candidate cells for the conditional handover, N being a positive integer;

And any one second candidate cell in the N second candidate cells is associated with the 1-bit indication information.

5. The method of claim 3, wherein the second handover is a conditional handover, the second message including configuration information of N second candidate cells for the conditional handover, N being a positive integer;

the indication information is the first bit mapping indication information, the first bit mapping indication information indicates that S second candidate cells in the N second candidate cells are associated with 1 bit indication information, and S is a positive integer less than or equal to N.

6. The method of claim 2, wherein the indication information comprises a configuration identification of at least one cell, the configuration identification being associated with configuration information of the at least one first candidate cell; or alternatively, the first and second heat exchangers may be,

the indication information is second bit mapping indication information.

7. The method of claim 6, wherein the indication information is the second bitmap indication information, the second bitmap indication information indicates that K first candidate cells among the M first candidate cells are associated with 1-bit indication information, and K is a positive integer less than or equal to M.

8. The method of claim 7, wherein the second handover is a conditional handover, the second message including configuration information of N second candidate cells for the conditional handover, N being a positive integer;

and any one second candidate cell in the N second candidate cells is associated with the second bit mapping indication information.

9. The method of claim 2, wherein the indication information comprises reconfiguration information for the first candidate cell;

10. The method of claim 1, wherein the terminal device performs a first operation comprising:

the target cell of the second handover is a first candidate cell in the M first candidate cells, and the terminal equipment reserves configuration information of the M first candidate cells, or the terminal equipment reserves configuration information of a first candidate cell related to the target cell of the second handover in the M first candidate cells; or alternatively, the first and second heat exchangers may be,

11. The method according to any one of claims 1-10, further comprising:

the second handover fails, and the terminal device executes Radio Resource Control (RRC) reestablishment;

the RRC reestablishes the selected target cell as a first candidate cell in the M first candidate cells, and the terminal equipment executes first switching according to the configuration information of the first candidate cell associated with the target cell.

12. The method according to any of claims 1-10, wherein the second handover is a conditional handover, the second message comprising configuration information of N second candidate cells for conditional handover, N being a positive integer;

the method further comprises the steps of:

and the RRC reestablishes the selected target cell as a second candidate cell in the N second candidate cells, and the terminal equipment executes conditional switching according to the second candidate cell.

13. A method of handover, comprising:

the network equipment sends a first message to the terminal equipment; the first message comprises configuration information of M first candidate cells switched by a first switch, wherein M is a positive integer;

the network equipment sends a second message to the terminal equipment; the second message includes configuration information of the target cell of the second handover and indication information indicating that configuration information of all of the M first candidate cells or at least one of the M first candidate cells is reserved, released, or reconfigured.

14. The method of claim 13, wherein the indication information is 1-bit indication information; or, the indication information is first bit mapping indication information.

15. The method of claim 14, wherein the second handover is a conditional handover, the second message including configuration information of N second candidate cells for the conditional handover, N being a positive integer;

16. The method of claim 14, wherein the second handover is a conditional handover, the second message including configuration information of N second candidate cells for the conditional handover, N being a positive integer;

The indication information is the first bit mapping indication information, and the first bit mapping indication information is used for indicating that S second candidate cells in the N second candidate cells are associated with 1 bit indication information, wherein S is a positive integer less than or equal to N.

17. The method of claim 14, wherein the indication information comprises a configuration identification of at least one cell, the configuration identification being associated with configuration information of the at least one first candidate cell; or alternatively, the first and second heat exchangers may be,

the indication information is second bit mapping indication information.

18. The method of claim 17, wherein the indication information is the second bitmap indication information, and the second bitmap indication information is used to indicate K first candidate cells among the M first candidate cells to associate 1-bit indication information, where K is a positive integer less than or equal to M.

19. The method of claim 18, wherein the second handover is a conditional handover, the second message including configuration information of N second candidate cells for the conditional handover, N being a positive integer;

20. The method of claim 13, wherein the indication information comprises reconfiguration information for the first candidate cell;

the reconfiguration information is used to indicate at least one of the following: releasing configuration information of part of the first candidate cells in the M first candidate cells, increasing configuration information of at least one first candidate cell in the M first candidate cells, releasing configuration information of the M first candidate cells or reserving configuration information of the M first candidate cells.

21. A communication device comprising means for performing the method of any of claims 1 to 12 or 13 to 20.

22. A communication device comprising a processor and a communication interface for receiving signals from other communication devices than the communication device and transmitting to the processor or sending signals from the processor to other communication devices than the communication device, the processor being configured to implement the method of any one of claims 1 to 12 or 13 to 20 by logic circuitry or executing code instructions.

23. A computer readable storage medium, characterized in that the computer readable storage medium stores a computer program which, when run, implements the method of any one of claims 1 to 12 or 13 to 20.

24. A computer program product, the computer program product comprising: computer program code which, when executed, implements the method of any one of claims 1 to 12 or 13 to 20.