Communication method and apparatus

Abstract

A communication method and apparatus, relating to the field of communications. In the method, a first network device receives a handover request message from a second network device, the first network device acquires a first CSI report and a second CSI report, the first CSI report being a CSI report detected by a terminal device on the basis of a reference signal of the first network device, and the second CSI report being a CSI report detected by the terminal device on the basis of a reference signal of the second network device, and if values of N parameters in the first CSI report are greater than or equal to values of corresponding parameters in the second CSI report, the first network device sends a handover completion message to the second network device, N being a positive integer. By using the design, the stability of a data transmission rate can be maintained during handover, and a sudden drop in the data rate during handover is avoided.

Description

Communication method and device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of the People's Republic of China on August 10, 2023, with application number 202311010420.3 and invention name "A Communication Method and Device", the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of communication technology, and in particular to a communication method and device. Background Art

[0004] Dual active protocol stack (DAPS) handover refers to a process in which a terminal device maintains a connection with the source base station after receiving the radio resource control (RRC) message for the handover and before successfully randomly accessing the target base station. DAPS handover can achieve zero-ms data transmission interruption during the cell handover process, considering latency.

[0005] During a DASP handover, after the target base station sends a handover completion message to the source base station, the source base station stops transmitting downlink data. When a terminal device first connects to the target base station, the data transmission rate may be low, and it may take some time for the data transmission rate to return to a higher level. Currently, if the target base station sends a handover completion message to the source base station too early, the target base station's data transmission rate may be low, affecting communication performance. If the target base station sends a handover completion message to the source base station too late, this will result in a longer data transmission delay.

[0006] Summary of the Invention

[0007] The present application provides a communication method and apparatus for alleviating the impact of cell switching on data transmission rate.

[0008] In a first aspect, the present application provides a communication method, which can be performed by a first network device or a communication device constituting the first network device (such as a chip or a unit or module with corresponding functions). The method includes: the first network device receives a handover request message from a second network device; the first network device obtains a first CSI report and a second CSI report, the first CSI report being a CSI report measured by a terminal device based on a reference signal of the first network device, and the second CSI report being a CSI report measured by the terminal device based on a reference signal of the second network device; if the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, the first network device sends a handover completion message to the second network device, where N is a positive integer.

[0009] Using the above method, the first network device obtains the first CSI report and the second CSI report. If the first network device determines that the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, the first network device sends a switching completion message to the second network device, and the second network device stops downlink data transmission. This can achieve data transmission through the second network device before the data rate on the first network device side is good and stable, so that the data transmission rate is maintained stable during the switching period, avoiding a sudden drop in the data rate during the switching period, improving the switching performance, and ensuring a good user experience.

[0010] In one possible design, the method is applied to DAPS switching.

[0011] In one possible design, when the first network device obtains the second CSI report, the first network device receives the second CSI report from the second network device or from the terminal device.

[0012] In one possible design, when the first network device receives the second CSI report from the second network device, the first network device receives the handover request message from the second network device, where the handover request message includes the second CSI report.

[0013] In one possible design, when the first network device receives the second CSI report from the terminal device, the first network device receives a random access message from the terminal device, where the random access message includes the second CSI report.

[0014] In one possible design, when the first network device obtains the first CSI report, the first network device receives the first CSI report from the terminal device.

[0015] In one possible design, the first CSI report is carried via a random access message.

[0016] In one possible design, the N parameters include at least one of CQI, L1-RSRP, and L1-SINR.

[0017] In one possible design, the first network device is a target network device; the second network device is a source network device.

[0018] In one possible design, the parameters in the first CSI report include at least one of the following: CQI, rank indicator RI, precoding matrix indicator PMI, L1-RSRP, L1-SINR; the parameters in the second CSI report include at least one of the following: CQI, RI, PMI, L1-RSRP, L1-SINR.

[0019] In one possible design, the second CSI report is the latest CSI report among the CSI reports measured by the terminal device based on the reference signal of the second network device; or the second CSI report is determined based on K CSI reports measured by the terminal device based on the reference signal of the second network device, where K is a positive integer greater than 1; or the second CSI report is the latest CSI report among the CSI reports measured by the terminal device based on the reference signal of the second network device when the terminal device receives the switching command from the second network device.

[0020] In one possible design, the reference signal of the first network device and the reference signal of the second network device are CSI-RS or SSB.

[0021] In a second aspect, the present application provides a communication method, which can be performed by a terminal device or a module (such as a chip) in the terminal device. The method includes: the terminal device receives a radio resource control reconfiguration message from a second network device, the radio resource control reconfiguration message indicating that the handover process of the terminal device is a DAPS handover; the terminal device sends a second CSI report to the first network device; the second CSI report is a CSI report measured by the terminal device based on a reference signal of the second network device.

[0022] Using the above method, the terminal device determines that the switching process of the terminal device is DAPS switching according to the radio resource control reconfiguration message, and sends a second CSI report to the first network device so that the second network device obtains the second CSI report.

[0023] In one possible design, the second CSI report is carried via a random access message.

[0024] In one possible design, the first network device is a target network device; the second network device is a source network device.

[0025] In one possible design, the parameters in the second CSI report include at least one of the following: CQI, RI, PMI, L1-RSRP, and L1-SINR.

[0026] In one possible design, the second CSI report is the latest CSI report among the CSI reports measured by the terminal device based on the reference signal of the second network device; or the second CSI report is determined based on K CSI reports measured by the terminal device based on the reference signal of the second network device, where K is a positive integer greater than 1; or the second CSI report is the latest CSI report among the CSI reports measured by the terminal device based on the reference signal of the second network device when the terminal device receives the switching command from the second network device.

[0027] In one possible design, the reference signal of the second network device is CSI-RS or SSB.

[0028] In a third aspect, the present application provides a communication method, which includes: a second network device sends a switching request message to a first network device; the second network device sends a second CSI report to the first network device; the second CSI report is a CSI report measured by the terminal device based on the reference signal of the second network device; the terminal device sends a first CSI report to the first network device; the first CSI report is a CSI report measured by the terminal device based on the reference signal of the first network device; the first network device receives the first CSI report and the second CSI report, and if the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, the first network device sends a switching completion message to the second network device, where N is a positive integer.

[0029] In a fourth aspect, the present application provides a communication method, which includes: a second network device sends a switching request message to a first network device; the switching request message includes a second CSI report; the second CSI report is a CSI report measured by the terminal device based on a reference signal of the second network device; the terminal device sends a first CSI report to the first network device; the first CSI report is a CSI report measured by the terminal device based on the reference signal of the first network device; the first network device receives the first CSI report and the second CSI report, and if the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, the first network device sends a switching completion message to the second network device, where N is a positive integer.

[0030] In a fifth aspect, the present application provides a communication method, which includes: a second network device sends a switching request message to a first network device; the second network device sends a wireless resource control reconfiguration message to a terminal device, and the wireless resource control reconfiguration message indicates that the switching process of the terminal device is a DAPS switching; the terminal device sends a first CSI report and a second CSI report to the first network device; the first CSI report is a CSI report measured by the terminal device based on the reference signal of the first network device; the second CSI report is a CSI report measured by the terminal device based on the reference signal of the second network device; the first network device receives the first CSI report and the second CSI report, and if the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, the first network device sends a switching completion message to the second network device, where N is a positive integer.

[0031] In a sixth aspect, the present application provides a communication method, which can be performed by a terminal device or a module (such as a chip) in the terminal device. The method includes: the terminal device receives first CSI configuration information and second CSI configuration information, the terminal device measures the reference signal of the first network device according to the first CSI configuration information to obtain a first CSI report, and measures the reference signal of the second network device according to the second CSI configuration information to obtain a second CSI report; if the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, the terminal device sends indication information to the first network device, the indication information is used to instruct the first network device to send a handover completion message to the second network device, where N is a positive integer.

[0032] The first CSI configuration information indicates the resources of the first reference signal, and the second CSI configuration information indicates the resources of the second reference signal; the terminal device receives the first reference signal sent by the first network device and measures to obtain a first CSI report; the terminal device receives the second reference signal sent by the second network device and measures to obtain a second CSI report.

[0033] Using the above method, the terminal device determines that the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, and then sends an indication message to the first network device, so that the first network device sends a switching completion message to the second network device according to the indication information, and the second network device then stops downlink data transmission. This can achieve data transmission through the second network device before the data rate on the first network device side is good and stable, so that the data transmission rate is maintained at a high level during the switching period, avoiding a sudden drop in the data rate during the switching period, improving the switching performance, and ensuring a good user experience.

[0034] In a possible design, it also includes: the terminal device receives a wireless resource control reconfiguration message from the second network device, and the wireless resource control reconfiguration message indicates that the switching process of the terminal device is DAPS switching.

[0035] In one possible design, the first CSI report is carried via a random access message.

[0036] In one possible design, the N parameters include at least one of CQI, L1-RSRP, and L1-SINR.

[0037] In one possible design, the first network device is a target network device; the second network device is a source network device.

[0038] In one possible design, the parameters in the first CSI report include at least one of the following: CQI, rank indicator RI, precoding matrix indicator PMI, L1-RSRP, L1-SINR; the parameters in the second CSI report include at least one of the following: CQI, RI, PMI, L1-RSRP, L1-SINR.

[0039] In one possible design, the second CSI report is the latest CSI report among the CSI reports measured by the terminal device based on the reference signal of the second network device; or the second CSI report is determined based on K CSI reports measured by the terminal device based on the reference signal of the second network device, where K is a positive integer greater than 1; or the second CSI report is the latest CSI report among the CSI reports measured by the terminal device based on the reference signal of the second network device when the terminal device receives the switching command from the second network device.

[0040] In one possible design, the reference signal of the first network device and the reference signal of the second network device are CSI-RS or SSB.

[0041] In a seventh aspect, the present application provides a communication method, which can be performed by a first network device or a module (such as a chip) in the first network device. The method includes: the first network device receiving a handover request message from a second network device; the first network device receiving instruction information from a terminal device, the instruction information instructing the first network device to send a handover completion message to the second network device; and the first network device sending the handover completion message to the second network device according to the instruction information.

[0042] Using this method, the first network device does not need to obtain the first and second CSI reports, thereby reducing signaling overhead between network devices. The first network device sends a handover completion message to the second network device based on the indication information, and the second network device then stops downlink data transmission. This allows data transmission through the second network device until the data rate on the first network device is good and stable. This maintains a high data transmission rate during the handover, avoids a sudden drop in the data rate during the handover, improves handover performance, and ensures a good user experience.

[0043] In one possible design, the first network device is a target network device; the second network device is a source network device.

[0044] In an eighth aspect, the present application provides a communication method, comprising: a second network device sends second CSI configuration information to a terminal device; the second network device sends a switching request message to the first network device; the first network device or the second network device sends first CSI configuration information to the terminal device; the terminal device receives the first CSI configuration information and the second CSI configuration information, the terminal device measures the reference signal of the first network device according to the first CSI configuration information to obtain a first CSI report, and measures the reference signal of the second network device according to the second CSI configuration information to obtain a second CSI report; if the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, the terminal device sends an indication message to the first network device, the indication message being used to instruct the first network device to send a switching completion message to the second network device, where N is a positive integer; the first network device receives the indication information from the terminal device, and the first network device sends the switching completion message to the second network device according to the indication information.

[0045] In a ninth aspect, the present application provides a communication method, which can be executed by a first network device or a module (such as a chip) in the first network device. The method includes: the first network device receives a switching request message from the second network device; the first network device sends third CSI configuration information and fourth CSI configuration information; wherein, the reporting period of the third CSI report configured by the third CSI configuration information is greater than the reporting period of the fourth CSI report configured by the fourth CSI configuration information; or, the reporting type of the fourth CSI report configured by the fourth CSI configuration information is dynamic reporting, and the reporting type of the third CSI report configured by the third CSI configuration information is periodic reporting; wherein, the third CSI report is obtained by the terminal device according to the reference signal measurement configured by the third CSI configuration information, and the fourth CSI report is obtained by the terminal device according to the reference signal measurement configured by the fourth CSI configuration information.

[0046] With the above design, the first network device additionally configures the terminal device with the fourth CSI configuration information in addition to the third CSI configuration information, so that the terminal device can perform the measurement of the reference signal of the first network and the reporting of the CSI report at a higher frequency, that is, the terminal device can report the third CSI report and the fourth CSI report, so that the network can quickly obtain the CSI report of the terminal device, and then can realize timely adjustment of the MCS according to the received CSI report, as well as rapid climbing of the MCS.

[0047] In one implementation, the first network device generates third CSI configuration information and fourth CSI configuration information, and then the first network device sends the third CSI configuration information and fourth CSI configuration information to the second network device, and the second network device sends the third CSI configuration information and fourth CSI configuration information to the terminal device.

[0048] In another implementation, the second network device negotiates with the first network device so that the second network device generates third CSI configuration information and fourth CSI configuration information, and the second network device sends the third CSI configuration information and fourth CSI configuration information to the terminal device.

[0049] In one possible design, it also includes: the first network device receives a second CSI report; the second CSI report is a CSI report measured by the terminal device based on the reference signal of the second network device; the first network device receives the fourth CSI report; if the values ​​of N parameters in the fourth CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, the first network device sends a switching completion message to the second network device, where N is a positive integer.

[0050] In one possible design, the first network device receives a second CSI report; the second CSI report is a CSI report measured by the terminal device based on the reference signal of the second network device; the first network device receives the third CSI report; if the values ​​of N parameters in the third CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, the first network device sends a switching completion message to the second network device, where N is a positive integer.

[0051] In one possible design, the first network device receives a second CSI report; the second CSI report is a CSI report measured by the terminal device based on a reference signal of the second network device; the first network device receives the third CSI report and the fourth CSI report; there is a value of N parameters in at least one CSI report of the third CSI report and the fourth CSI report that is greater than or equal to the value of the corresponding parameter in the second CSI report, and the first network device sends a switching completion message to the second network device, where N is a positive integer.

[0052] In one possible design, the first network device is a target network device; the second network device is a source network device.

[0053] In the tenth aspect, the present application provides a communication method, which includes: the second network device sends a switching request message to the first network device; the first network device sends third CSI configuration information and fourth CSI configuration information; wherein, the reporting period of the third CSI report configured by the third CSI configuration information is greater than the reporting period of the fourth CSI report configured by the fourth CSI configuration information; or, the reporting type of the fourth CSI report configured by the fourth CSI configuration information is dynamic reporting, and the reporting type of the third CSI report configured by the third CSI configuration information is periodic reporting; the terminal device receives the third CSI configuration information and the fourth CSI configuration information, the terminal device measures the reference signal configured by the third CSI configuration information according to the third CSI configuration information to obtain the third CSI report, and measures the reference signal configured by the fourth CSI configuration information according to the fourth CSI configuration information to obtain the fourth CSI report; the terminal device sends the third CSI report and the fourth CSI report to the first network device.

[0054] In an eleventh aspect, the present application provides a communication device, which can be applied to a terminal device or a network device, and the device includes a unit for executing any of the methods described in any of the above aspects.

[0055] In the twelfth aspect, the present application provides a communication device comprising at least one processing element and at least one storage element, wherein the at least one storage element is used to store programs and data, and the at least one processing element is used to read and execute the programs and data stored in the storage element, so that the method described in any one of the above aspects of the present application is implemented.

[0056] In a thirteenth aspect, the present application further provides a computer program, which, when executed on a computer, enables the computer to execute any of the methods described in any of the above aspects.

[0057] In the fourteenth aspect, the present application provides a communication device, which includes: an interface circuit; the interface circuit is used to provide input and / or output of programs or instructions to at least one processor; the at least one processor is used to execute the program or instructions so that the communication device can implement any method described in any of the above aspects.

[0058] In one possible manner, the communication device includes the at least one processor.

[0059] In one possible embodiment, the communication device further includes one or more memories; wherein the one or more memories store one or more programs, and when the programs are executed by the one or more processors, the communication device executes any one of the methods described in any one of the above aspects.

[0060] In a fifteenth aspect, the present application provides a computer storage medium storing a software program. When the software program is read and executed by one or more processors, it can implement any of the methods described in any of the above aspects.

[0061] In a sixteenth aspect, the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute any of the methods described in any of the above aspects.

[0062] In the seventeenth aspect, the present application provides a chip system, which includes at least one chip and a memory, and the at least one chip is used to read and execute the program stored in the memory to implement any of the methods described in any of the above aspects.

[0063] In aspect 18, the present application provides a communication system, which includes a terminal device, a first network device and a second network device, wherein the terminal device executes the method described in any one of the second aspect or the sixth aspect, and the first network device executes the method described in any one of the first aspect, the seventh aspect or the ninth aspect.

[0064] Based on the implementations provided in the above aspects, this application can also be further combined to provide more implementations. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] FIG1 is a schematic diagram of the architecture of a mobile communication system used in an embodiment of the present application;

[0066] FIG2 is a flow chart of DAPS switching applied in an embodiment of the present application;

[0067] FIG3 is one of the flow charts of an overview of a communication method provided by the present application;

[0068] FIG4 is a second flow chart of an overview of a communication method provided by this application;

[0069] FIG5 is a third flow chart of an overview of a communication method provided by this application;

[0070] FIG6 is a fourth flow chart of an overview of a communication method provided by the present application;

[0071] FIG7 is a fifth flow chart of an overview of a communication method provided by the present application;

[0072] FIG8 is a sixth flow chart of an overview of a communication method provided by this application;

[0073] FIG9 is a sixth flow chart of an overview of a communication method provided by this application;

[0074] FIG10 is a seventh flow chart of an overview of a communication method provided by the present application;

[0075] FIG11 is a schematic structural diagram of a communication device provided by the present application;

[0076] FIG12 is a schematic structural diagram of another communication device provided in this application. DETAILED DESCRIPTION

[0077] The embodiments of the present application can be applied to various communication systems, such as: global system for mobile communications (GSM) system, code division multiple access (CDMA) system, wideband code division multiple access (WCDMA) system, general packet radio service (GPRS), long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), universal mobile telecommunication system (UMTS), world-wide interoperability for microwave access (WIMAX) communication system, fifth generation (5G) system or new radio (NR), or applied to future communication systems or other similar communication systems.

[0078] Figure 1 is a schematic diagram of the architecture of a communication system 1000 used in an embodiment of the present application. As shown in Figure 1 , the communication system includes a radio access network 100 and a core network 200. Optionally, the communication system 1000 may also include the Internet 300. The radio access network 100 may include at least one radio access network device (such as 110a and 110b in Figure 1 ) and at least one terminal device (such as 120a-120j in Figure 1 ). The terminal device is wirelessly connected to the radio access network device, and the radio access network device is wirelessly or wiredly connected to the core network. The core network device and the radio access network device may be independent and distinct physical devices, or the functions of the core network device and the logical functions of the radio access network device may be integrated into the same physical device, or a single physical device may integrate some of the functions of the core network device and some of the functions of the radio access network device. Terminal devices and radio access network devices may be connected to each other via wired or wireless connections. FIG1 is only a schematic diagram. The communication system may further include other network devices, such as wireless relay devices and wireless backhaul devices, which are not shown in FIG1 .

[0079] A radio access network device can be a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next-generation NodeB (gNB) in a fifth-generation (5G) mobile communication system, a next-generation base station in a sixth-generation (6G) mobile communication system, a base station in a future mobile communication system, or an access node in a Wi-Fi system. It can also be a module or unit that performs some of the functions of a base station, such as a centralized unit (CU) or a distributed unit (DU). The CU performs the functions of the base station's radio resource control protocol and packet data convergence protocol (PDCP), as well as the service data adaptation protocol (SDAP). The DU performs the functions of the base station's radio link control layer and medium access control (MAC) layer, as well as some or all of the physical layer. For detailed descriptions of each of these protocol layers, please refer to the relevant technical specifications of the Third Generation Partnership Project (3GPP). The wireless access network device can be a macro base station (such as 110a in Figure 1), a micro base station or an indoor station (such as 110b in Figure 1), a relay node, a donor node, etc. The embodiments of this application do not limit the specific technology and device form used by the wireless access network device. For ease of description, the following description uses a network device as an example of a wireless access network device.

[0080] Terminal devices may also be referred to as terminal devices, user equipment (UE), mobile stations, mobile terminal devices, etc. Terminal devices can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IOT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grid, smart furniture, smart office, smart wearable, smart transportation, smart city, etc. Terminal devices can be mobile phones, tablet computers, computers with wireless transceiver functions, wearable devices, vehicles, drones, helicopters, airplanes, ships, robots, robotic arms, smart home devices, etc. The embodiments of the present application do not limit the specific technology and specific device form adopted by the terminal devices.

[0081] Network devices and terminal devices can be fixed or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; they can also be deployed on aircraft, balloons, and artificial satellites. The embodiments of this application do not limit the application scenarios of network devices and terminal devices.

[0082] The roles of network devices and terminal devices can be relative. For example, the helicopter or drone 120i in Figure 1 can be configured as a mobile network device. To terminal devices 120j accessing the wireless access network 100 via 120i, drone 120i is a network device. However, to network device 110a, 120i is a terminal device, meaning that communication between 110a and 120i occurs via a wireless air interface protocol. Of course, communication between 110a and 120i can also occur via an interface protocol between network devices. In this case, 120i is also a network device relative to 110a. Therefore, both network devices and terminal devices can be collectively referred to as communication devices. 110a and 110b in Figure 1 can be referred to as communication devices with network device functionality, while 120a-120j in Figure 1 can be referred to as communication devices with terminal device functionality.

[0083] Network devices and terminal devices, network devices and network devices, and terminal devices and terminal devices can communicate through authorized spectrum, unauthorized spectrum, or both; can communicate through spectrum below 6 gigahertz (GHz), spectrum above 6 GHz, or spectrum below 6 GHz and spectrum above 6 GHz simultaneously. The embodiments of the present application do not limit the spectrum resources used for wireless communications.

[0084] In the embodiments of the present application, the functions of the network device may also be performed by a module (such as a chip) in the network device, or by a control subsystem that includes the network device functions. The control subsystem that includes the network device functions here may be a control center in the above-mentioned application scenarios such as smart grid, industrial control, smart transportation, and smart city. The functions of the terminal device may also be performed by a module (such as a chip or a modem) in the terminal device, or by a device that includes the terminal device functions.

[0085] In the embodiments of the present application, the network device sends a downlink signal or downlink information to the terminal device, and the downlink information is carried on the downlink channel; the terminal device sends an uplink signal or uplink information to the base station, and the uplink information is carried on the uplink channel. In order to communicate with the base station, the terminal device needs to establish a wireless connection with the cell controlled by the base station. The cell with which the terminal device has established a wireless connection is called the serving cell of the terminal device. When the terminal device communicates with the serving cell, it will also be interfered with by signals from neighboring cells.

[0086] It can be understood that in the embodiments of the present application, the physical downlink shared channel (PDSCH), physical downlink control channel (PDCCH), physical uplink control channel (PUCCH) and physical uplink shared channel (PUSCH) are only used as examples of downlink data channels, downlink control channels, uplink control channels and uplink data channels, respectively. In different systems and different scenarios, data channels and control channels may have different names, and the embodiments of the present application do not limit this.

[0087] The following is a brief introduction to the basic technical concepts involved in this application:

[0088] (1) Reference signal

[0089] A reference signal is a known signal provided by the transmitter to the receiver for channel estimation or channel sounding. Reference signals can be used for channel and interference measurements. For example, a terminal can determine the channel status by measuring parameters such as reference signal receiving quality (RSRQ), signal-to-noise ratio (SNR), signal-to-interference plus noise ratio (SINR), channel quality indicator (CQI), and precoding matrix indicator (PMI).

[0090] Specifically, the reference signal involved in the embodiments of the present application may be a channel state information reference signal (CSI-RS) or a synchronization signal and physical broadcast channel block (SSB).

[0091] (2) Reference signal resources

[0092] The reference signal resources may specifically include at least one of the reference signal time-frequency resources, antenna ports, power resources, and scrambling codes. The network device may send the reference signal based on the reference signal resources, and the terminal may receive the reference signal based on the reference signal resources.

[0093] When the reference signal is a CSI-RS, the reference signal resource may be a CSI-RS resource. When the reference signal is an SSB, the reference signal resource may be an SSB resource.

[0094] (3) CSI report

[0095] In the process of a wireless signal from the transmitter to the receiver through the wireless channel, it may experience scattering, reflection, and energy attenuation with distance, resulting in fading. In addition, the wireless signal may also be interfered with by other signals at the receiver, thereby affecting the reception of the wireless signal. The CSI report can also be referred to as CSI. The CSI report is used to characterize the characteristics of the wireless channel. The CSI report may include but is not limited to at least one of the following parameters: channel quality indicator (CQI), rank indication (RI), precoding matrix indicator (PMI), layer 1 signal to interference plus noise ratio (L1-SINR), layer 1 reference signal receiving power (L1-RSRP). In addition, the CSI report may also include other parameters, which are not limited in this application. The CSI can be sent by the terminal to the network device through PUCCH or PUSCH.

[0096] (4) CSI configuration information

[0097] The CSI configuration information may include a CSI measurement configuration (CSI-ResourceConfig). The CSI measurement configuration includes the resource configuration and resource type configuration of the reference signal, which is used to configure relevant information of the reference signal resources, such as the time-frequency resources, antenna ports, power resources, or scrambling codes of the reference signal. The resource type configuration may include, but is not limited to, periodic, aperiodic, or semi-static. For example, the CSI measurement configuration may include resource mapping (resourceMapping), periodicity, and offset (periodicityAndOffset) of the reference signal. The period and offset include the reference signal transmission period (also referred to as the reference signal period) and the offset (also referred to as the time slot offset).

[0098] In addition, the CSI configuration information may also include a CSI report reporting configuration (CSI-ReportConfig). The CSI report reporting configuration is primarily used to configure parameters related to the CSI report. The CSI report reporting configuration includes, but is not limited to, a report configuration identifier, the number of reports, the reporting type, and CSI report reporting parameters. The reporting type includes, but is not limited to, periodic reporting, aperiodic reporting, or semi-continuous reporting.

[0099] It is understandable that the CSI report reporting configuration and the CSI measurement configuration may be sent together or separately, and this application does not limit this.

[0100] The following describes the basic process of DAPS switching with reference to Figure 2:

[0101] S201: The source base station sends a measurement configuration to the UE.

[0102] Correspondingly, the UE receives the measurement configuration from the source base station. The measurement configuration sent by the source base station to the UE is a layer 3 measurement configuration, ie, a radio resource measurement (RRM) configuration.

[0103] S202: The UE performs measurement according to the measurement configuration sent by the source base station, and sends a measurement report to the source base station.

[0104] Correspondingly, the source base station receives the measurement report from the UE.

[0105] S203: The source base station decides the cell to which the UE switches based on information such as the measurement report and RRM configuration.

[0106] S204: The source base station sends a handover request message to the target base station.

[0107] Correspondingly, the target base station receives the handover request message from the source base station.

[0108] Among them, the handover request message is used by the target base station to prepare for handover, and the handover request message may include but is not limited to the following information: target cell identity (ID), parameters for deriving keys (e.g., KgNB*), cell radio network temporary identifier (C-RNTI) of the UE in the source base station, RRM configuration, access stratum (AS) configuration including antenna information and downlink (DL) carrier frequency, mapping rules of the current quality of service (QoS) flow applied to the UE to the data radio bearer (DRB), system information block (SIB) 1 from the source base station, UE capabilities of different radio access technologies (RATs), protocol data unit (PDU) session related information, UE reported measurement information, beam related information. Among them, the measurement information reported by the UE here is the filtered measurement information of layer 3. In addition, the source base station can also request one or more DRBs for DAPS handover.

[0109] S205: The target base station performs admission control.

[0110] For example, if the target base station obtains slice information, it should perform slice-aware admission control. If a PDU session is associated with an unsupported slice, the target base station may reject such a PDU session.

[0111] S206: The target base station sends a handover request acknowledgement message to the source base station.

[0112] Correspondingly, the source base station receives a handover request confirmation message from the target base station.

[0113] Exemplarily, the target gNB prepares for handover and includes a transparent container in a Handover Confirm Request message, which is sent as an RRC message to the UE to perform the handover. The Handover Confirm Request message also indicates whether the target gNB accepts DAPS handover.

[0114] It should be noted that once the source base station receives the handover request confirmation message, or once the transmission of the handover command is initiated in the downlink (that is, the source base station sends an RRC message including the handover command to the UE (that is, S207)), the data forwarding from the source base station to the target base station can be initiated. For DRBs configured with DAPS, the downlink packet data convergence protocol (PDCP) service data unit (SDU) is forwarded using the PDCP sequence number (SN) assigned by the source base station until the PDCP SN is assigned by the target base station in S211. In addition, for DRBs configured with DAPS, the source base station will not stop sending downlink data packets to the UE until the handover completion message is received from the target base station in S210.

[0115] S207: The source base station sends an RRC reconfiguration message to the UE.

[0116] Correspondingly, the UE receives an RRC reconfiguration message from the source base station. The RRC reconfiguration message can be used to trigger an air interface handover.

[0117] Exemplarily, the source base station sends an RRC reconfiguration message according to the transparent container in the handover confirmation request message received in S206.

[0118] The RRC reconfiguration message includes the information required to access the target base station: at least the target cell ID, the new C-RNTI, and the target base station security algorithm identifier for the selected security algorithm. The message also includes a set of dedicated random access channel (RACH) resources, the association between RACH resources and synchronization signal blocks (synchronization signal / PBCH blocks, SSBs), the association between RACH resources and UE-specific CSI-RS configurations, common RACH resources, and system information about the target cell.

[0119] The RRC reconfiguration message also indicates whether the radio bearer of the target cell is configured as a DAPS bearer. When the bearer is configured as a DAPS bearer, the UE can determine that the UE handover process is a DAPS handover according to the indication.

[0120] Exemplarily, the RRC reconfiguration message includes a handover command, which is used to instruct the UE to perform a handover. For example, the handover command can be understood as the synchronization reconfiguration field in the RRC reconfiguration message. Alternatively, the handover command can be understood as the RRC reconfiguration message including the synchronization reconfiguration field. Alternatively, the handover command can be understood as the RRC reconfiguration message.

[0121] The following description methods have the same meaning in this application: the source base station sends an RRC reconfiguration message to the UE, which can also be described as the source base station sends an RRC reconfiguration message including a switching command to the UE, or the source base station sends a switching command to the UE.

[0122] S208: For the DRB configured with DAPS, the source base station sends an early status transfer message to the target base station.

[0123] Correspondingly, the target base station receives the early state transmission message from the source base station.

[0124] The early status transmission message includes a downlink count value, where the downlink count value is used to indicate the PDCP SN and hyper frame number (HFN) of the first PDCP SDU forwarded by the source base station to the target base station.

[0125] S209: The UE sends an RRC reconfiguration complete message to the target base station.

[0126] Correspondingly, the target base station receives an RRC reconfiguration complete message from the UE.

[0127] Exemplarily, the UE accesses the target base station through a random access procedure and sends an RRC reconfiguration complete message to the target base station. The RRC reconfiguration complete message may be included in the random access message 3.

[0128] In a DAPS handover, the UE does not detach from the source base station after receiving the RRC reconfiguration message. Upon receiving a source release indication from the target base station, the UE releases the source base station and stops sending uplink data to and receiving downlink data from the source base station. The DAPS handover is considered complete only after the UE releases the source base station in accordance with the release indication from the target base station.

[0129] The present application does not limit the specific location of displaying the release indication, nor does it limit the sequence of displaying the release indication, S210 , and SS211 .

[0130] S210: In the case of DAPS handover, the target base station sends a handover success message to the source base station.

[0131] Correspondingly, the source base station receives a handover completion message from the target base station.

[0132] The handover completion message may also be referred to as a handover success message, and the handover completion message is used to notify the source base station that the UE has successfully accessed the target base station (or target cell).

[0133] S211: The source base station sends an SN status transfer message to the target base station for the DRB configured with DAPS.

[0134] Correspondingly, the target base station receives the SN status transmission message from the source base station.

[0135] The SN status transmission message is used to transmit the uplink PDCP SN reception status and downlink PDCP SN transmission status of the DRB maintained by the PDCP state (i.e., for the radio link control (RLC) acknowledged mode (AM)). The uplink PDCP SN reception status includes at least the PDCP SN of the first lost UL PDCP SDU. In addition, if there is a bitmap of the reception status of the out-of-order UL PDCP SDU that the UE needs to retransmit in the target cell, the uplink PDCP SN reception status may also include the bitmap. The downlink PDCP SN transmission status indicates the PDCP SN that the target base station will allocate to the new PDCP SDU, which does not yet have a PDCP SN.

[0136] S212: The target base station sends a path switch request message to the access and mobility management function (AMF) network element.

[0137] Correspondingly, the AMF network element receives a path switching request message from the target base station.

[0138] Among them, the path switching request message is used to trigger the 5G core network (5G core, 5GC) to switch the downlink data path to the target base station and establish an NG-C interface instance to the target base station.

[0139] The 5GC switches the downlink data path to the target eNB. The user plane function (UPF) sends one or more "end marker" packets to the source eNB on the old path of each PDU session / tunnel, and then releases the user plane or transport network layer (TNL) resources of the source eNB.

[0140] S213: The AMF network element sends a path switch request acknowledgement message to the target base station.

[0141] Correspondingly, the target base station receives a path switching request confirmation message from the AMF network element.

[0142] S214: The target base station sends a UE context release message to the source base station.

[0143] Correspondingly, the source base station receives a UE context release message from the target base station.

[0144] The UE context release message is used to notify the source base station that the path switch is complete. The source network element can then release the radio and control plane resources associated with the UE context. Any ongoing data forwarding can continue.

[0145] As shown in Figure 2, when the UE connects to the target base station and sends an RRC Reconfiguration Complete message to the target base station, the target base station sends a Handover Complete message to the source base station, notifying the source base station that the UE has connected to the target base station. Upon receiving the Handover Complete message from the target base station, the source base station stops downlink data transmission. However, there is no standard for when the target base station sends the Handover Complete message (in the figure, HANDOVERSUCCES) to the source base station.

[0146] As a base station implementation, the target base station can immediately send a handover complete message to the source base station after receiving the RRC reconfiguration complete message. At this time, the source base station stops downlink data transmission, and the data rate on the target base station side is generally lower. Possible reasons for the lower data rate include but are not limited to the following:

[0147] First, when a terminal device first connects to the target base station, the modulation and coding scheme (MCS) value set by the target base station for the terminal device may be low, for example, the MCS value may be 2. It takes some time for the target base station to set an appropriate MCS value for the terminal device, restoring the data transmission rate to a higher level. Adjusting the MCS value from a low value to an appropriate value takes time.

[0148] Secondly, there is a delay in the CSI measurement and reporting of the target cell. The UE reports the CSI report after accessing the target cell for a period of time, which is not conducive to adjusting to the appropriate MCS as soon as possible.

[0149] The RRC reconfiguration message including the handover command sent by the source base station to the UE may include the CSI configuration of the target cell. After receiving the RRC reconfiguration message including the handover command, the UE must first access the target cell, then perform reference signal measurements on the target cell according to the CSI measurement configuration in the target cell's CSI configuration, and report the corresponding CSI report. As a result, the UE will not report the CSI report of the target cell until some time after accessing the target base station.

[0150] Third, the CSI reports submitted by the UE in the first few times after accessing the target cell may be poor. In this case, if the source base station stops downlink data transmission early, it will not be conducive to maintaining a high data transmission rate.

[0151] Based on the network system architecture shown in FIG1 and the contents of the above-mentioned related technical introduction, several possible communication methods are provided in the embodiments of the present application. The execution subjects of each communication method are introduced by taking the first network device, the second network device and the terminal device as examples. For example, the first network device and the second network device can be the access network device 110a or the access network device 110b in FIG1 . The terminal device can be any terminal device 120 shown in FIG1 . In addition, it should be understood that the first network device can also be replaced by a communication device having the function of the first network device or a chip, unit or module inside the communication device having the function of the first network device, and the second network device is similar. The terminal device can also be replaced by a communication device having the function of a terminal device or a chip, unit or module inside the communication device having the function of a terminal device.

[0152] In the following embodiments, the first network device and the second network device are different. The first network device is a target base station, and the second network device is a source base station. Alternatively, the first network device is a network device where the target cell to which the terminal device is switching is located, and the second network device is a network device where the source cell accessed by the terminal device is located, or a network device that sends a handover command. Optionally, the source cell and the target cell belong to different network devices. The reference signal of the first network device and the reference signal of the second network device are CSI-RS or SSB.

[0153] It should be noted that the following embodiments can be applied to the DAPS switching process and other switching processes, and this application is not limited thereto. In addition, the following embodiments do not reflect the complete switching process, but only some steps in the switching process. The complete process and specific details of the switching process can be referred to in Figure 2 above, and the repeated parts will not be repeated.

[0154] FIG3 exemplarily shows a possible flow diagram of a communication method provided in an embodiment of the present application. As shown in FIG3 , the method includes:

[0155] S301: The second network device sends a handover request message to the first network device.

[0156] Correspondingly, the first network device receives the switching request message from the second network device.

[0157] Before the second network device sends the switching request message to the first network device, the terminal device and the second network device may also execute S201 to S203 above. In addition, for the specific content of the switching request message, please refer to S204 above, which will not be repeated here.

[0158] In one possible implementation, the handover request message may include the second CSI report.

[0159] In another possible implementation, the second CSI report may be carried in a message between network devices, that is, the second CSI report may not be carried in the handover request message, as shown by the dotted line in Figure 3. It is understandable that the second network device may send the second CSI report to the first network device after the handover request message, that is, after S301 and before S305.

[0160] Exemplarily, the second network device may determine that the handover of the terminal device is a DASP handover, and then the second network device may choose to carry the second CSI report through a handover request message or a separate message.

[0161] Among them, the second CSI report is a CSI report measured by the terminal device based on the reference signal of the second network device, or the second CSI report is a CSI report measured by the terminal device under the second network device, or the second CSI report is a CSI report measured by the terminal device by measuring the reference signal of the second network device.

[0162] Exemplarily, a terminal device may receive CSI configuration information, i.e., second CSI configuration information, from a second network device, where the second CSI configuration information indicates a resource for a second reference signal. The terminal device receives the second reference signal sent by the second network device and measures to obtain a second CSI report. For example, the terminal device measures the reference signal sent by the second network device based on the second CSI configuration information, and reports a corresponding CSI report to the second network device. For the specific content of the CSI configuration information, please refer to the above-mentioned relevant description and will not be repeated here.

[0163] For example, the second CSI configuration information may include a CSI measurement configuration and a CSI report reporting configuration. The CSI measurement configuration includes a resource configuration and a resource type configuration for a reference signal sent by the second network device. The CSI report reporting configuration includes parameters related to CSI report reporting. The terminal device may measure the reference signal of the second network device according to the CSI measurement configuration in the second CSI configuration, and report the obtained CSI report to the second network device according to the CSI report reporting configuration in the second CSI configuration.

[0164] In a possible implementation, the second CSI report may be any one of the CSI reports measured by the terminal device based on the reference signal of the second network device.

[0165] In one possible implementation, if the reference signal resource in the second CSI configuration is periodically configured and the reporting type of the CSI report is periodic reporting, the terminal device can periodically measure the reference signal of the second network device to obtain multiple CSI reports, and the second network device can also obtain multiple CSI reports reported by the terminal device. In this case, the second CSI report has the following possible forms, but is not limited to the following forms:

[0166] Form a: The second CSI report is the latest CSI report among the CSI reports measured by the terminal device based on the reference signal of the second network device.

[0167] Or it can also be described as that the second CSI report is the CSI report obtained by the terminal device at the last measurement among multiple CSI reports obtained based on the reference signal of the second network device.

[0168] Exemplarily, both the terminal device and the network device may obtain multiple CSI reports, and use the CSI report with the latest measurement time among the multiple CSI reports as the second CSI report.

[0169] Form b: The second CSI report is determined based on K CSI reports measured by the terminal device based on the reference signal of the second network device, where K is a positive integer greater than 1.

[0170] Exemplarily, both the terminal device and the network device may obtain multiple CSI reports, and then may obtain the average value of each parameter in the CSI report based on K CSI reports among the multiple CSI reports to obtain a second CSI report.

[0171] For example, assuming that each CSI report includes CQI, L1-SINR, and L1-RSRP, the K CQIs obtained from the K CSI reports are averaged to obtain the average CQI value, the K L1-SINRs are averaged to obtain the average L1-SINR value, and the K L1-RSRPs are averaged to obtain the average L1-RSRP value. Therefore, the second CSI report includes the average CQI value, the average L1-SINR value, and the average L1-RSRP value.

[0172] It is understandable that the above description is only based on the example of averaging, and other methods may be used to determine the second CSI report, such as weighted averaging, etc. This application does not limit this.

[0173] Form c: The second CSI report is a CSI report measured by the terminal device based on the reference signal of the second network device when the terminal device receives a handover command from the second network device.

[0174] It should be noted that the second CSI report is not necessarily the CSI report measured when the terminal device receives the switching command, but is the CSI report that already exists (or has been stored) when the terminal device receives the switching command.

[0175] Exemplarily, the CSI report measured by the terminal device based on the reference signal of the second network device when the terminal device receives the handover command from the second network device can be understood as the CSI report based on the reference signal of the second network device stored by the terminal device when the terminal device receives the handover command from the second network device. That is, the second CSI report can be the CSI report of the most recent measurement of the reference signal of the second network device before the terminal device receives the handover command from the second network device.

[0176] For example, in a scenario where the second CSI report is sent by the second network device to the first network device, the second CSI report is the most recently stored CSI report among the existing (or stored) CSI reports when the second network device sends a switching command to the terminal device.

[0177] It will be understood that the possible forms of the above-mentioned second CSI reports are merely examples and are not intended to limit the present application.

[0178] S302: The first network device sends a handover request confirmation message to the second network device. Correspondingly, the second network device receives the handover request confirmation message from the first network device.

[0179] Exemplarily, the first network device may also perform admission control before executing S302. The handover request confirmation message includes a transparent container, which is sent to the terminal device as content in a radio resource control reconfiguration message for the terminal device to perform handover. For the specific content included in the handover request confirmation message, please refer to S207 above.

[0180] S303: The second network device sends a radio resource control reconfiguration message to the terminal device.

[0181] Correspondingly, the terminal device receives a radio resource control reconfiguration message from the second network device.

[0182] S304: The terminal device synchronizes to the target base station and sends a radio resource control reconfiguration completion message to the first network device.

[0183] Exemplarily, the terminal device completes synchronization to the target base station through a random access process.

[0184] Correspondingly, the first network device receives a radio resource control reconfiguration completion message from the terminal device.

[0185] The radio resource control reconfiguration complete message may be included in a random access message, for example, random access message 3.

[0186] In a possible implementation, the random access message may further include the first CSI report. For example, the random access message 3 may further include the first CSI report.

[0187] In another possible implementation, the terminal device may send the first CSI report to the first network device after S304, as shown by the dotted line in Figure 3, and before S305, that is, the first CSI report may not be carried by the wireless resource control reconfiguration completion message.

[0188] Exemplarily, the handover request confirmation message in S302 may include a first CSI configuration, wherein the first CSI configuration information indicates a resource of a first reference signal, and the terminal device receives the first reference signal sent by the first network device and measures to obtain a first CSI report.

[0189] Exemplarily, the radio resource control reconfiguration message (ie, S303) sent by the second network device to the terminal device may include the first CSI configuration. The terminal device may measure the reference signal sent by the first network device according to the first CSI configuration and report a first CSI report to the first network device.

[0190] It should be noted that after the terminal device receives the handover command or accesses the target cell, it performs CSI measurement of the reference signal of the first network device. For example, it is assumed that the first CSI configuration may include a CSI measurement configuration and a reporting configuration of the CSI report. The CSI measurement configuration includes the resource configuration and resource type configuration of the reference signal sent by the first network device. The reporting configuration of the CSI report includes parameters related to the CSI report reporting. The terminal device can measure the reference signal of the first network device according to the CSI measurement configuration in the first CSI configuration, and report the obtained first CSI report to the first network device according to the reporting configuration of the CSI report in the first CSI configuration.

[0191] Among them, the first CSI report is a CSI report measured by the terminal device based on the reference signal of the first network device, or the first CSI report is a CSI report measured by the terminal device under the first network device, or the first CSI report is a CSI report measured by the terminal device by measuring the reference signal of the first network device.

[0192] S305: The first network device determines, based on the received first CSI report and the received second CSI report, that values ​​of N parameters in the first CSI report are greater than or equal to values ​​of corresponding parameters in the second CSI report, where N is a positive integer.

[0193] Exemplarily, the N parameters include at least one of CQI, L1-RSRP, and L1-SINR.

[0194] Illustratively, the first CSI report may be replaced by a first CSI result; and the second CSI report may be replaced by a second CSI result.

[0195] S306: The first network device sends a handover completion message to the second network device.

[0196] Correspondingly, the second network device receives the switching completion message from the first network device.

[0197] It is understandable that in the present application, the terminal device and the first network device can obtain P first CSI reports. Among the P first CSI reports, there may be p first CSI reports, and the values ​​of the N parameters in each of the p first CSI reports may be greater than or equal to the values ​​of the corresponding parameters in the second CSI report. Wherein, P and p are positive integers. For example, if the resource of the reference signal in the first CSI configuration is periodic configuration, and the reporting type of the CSI report is periodic reporting, the terminal device can periodically measure the reference signal of the first network device, thereby obtaining multiple first CSI reports, and the second network device can also obtain multiple first CSI reports reported by the terminal device. That is, the first network device can obtain multiple first CSI reports and determine whether the values ​​of the N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report based on each first CSI report obtained, until a first CSI report satisfies the condition that the values ​​of the N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, and then continue to execute S306.

[0198] Exemplarily, the first network device determines that a received first CSI report reported based on a reference signal of the first network device satisfies a condition, that is, the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of corresponding parameters in the second CSI report, and then sends a handover completion message to the second network device. If the second network device determines that a received first CSI report reported based on a reference signal of the first network device does not satisfy a condition, that is, the values ​​of M parameters in the first CSI report are less than the values ​​of corresponding parameters in the second CSI report, where the N references include the M parameters, then the first network device does not send a handover completion message to the second network device.

[0199] For example, assuming that N parameters include CQI, a first network device receives a first CSI report 1 from a terminal device, where the first CSI report 1 is a first CSI report measured by the terminal device based on a reference signal of the first network device. If the first network device determines that the CQI value in the first CSI report 1 is less than the CQI value in the second CSI report, the first network device does not send a handover complete message to the second network device. Therefore, the second network device and the terminal device remain connected. Furthermore, the first network device receives a first CSI report from the next reporting period, for example, denoted as first CSI report 2. After receiving first CSI report 2, the first network device determines whether the CQI value in first CSI report 2 is greater than or equal to the CQI value in the second CSI report. If so, the first network device sends a handover complete message to the second network device. Otherwise, the first network device waits for the first CSI report from the next reporting period until the CQI value in the received first CSI report X is greater than or equal to the CQI value in the second CSI report. At this point, the first network device sends a handover complete message to the second network device, where X is a positive integer.

[0200] It should be noted that before the first network device sends a handover completion message to the second network device, the first network device needs to determine whether preset condition 1 is met. The preset condition 1 in the above embodiment is that the values ​​of the N parameters in the currently received first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report. In addition, the first network device can also determine whether preset condition 2 is met. Preset condition 2 can be to start timing from the receipt of the radio resource control reconfiguration completion message by the first network device until a preset duration (for example, 30ms) is reached, that is, the timer is started when the radio resource control reconfiguration completion message is received, and the duration of the timer is the preset duration. Therefore, before the first network device sends a handover completion message to the second network device, the first network device determines that preset condition 1 and / or preset condition 2 are met, and the first network device sends a handover completion message to the second network device. The above preset conditions 1 and preset conditions 2 are only examples. Based on the same concept, those skilled in the art can also propose other preset conditions.

[0201] As an optional solution, S306 can also be replaced by the first network device sending a display release instruction to the terminal device. Accordingly, the terminal device receives the display release instruction from the first network device, releases the second network device, and stops sending uplink data to the second network device and receiving downlink data.

[0202] Using the above method, the terminal device sends a first CSI report to the first network device, and the second network device sends a second CSI report to the first network device. If the first network device determines that the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, the first network device sends a handover completion message to the second network device, and the second network device stops downlink data transmission. This allows data transmission through the second network device until the data rate on the first network device is good and stable, maintaining a stable data transmission rate during the handover, avoiding a sudden drop in the data rate during the handover, improving handover performance, and ensuring a good user experience.

[0203] FIG4 exemplarily shows a possible flow diagram of a communication method provided in an embodiment of the present application. As shown in FIG4 , the method includes:

[0204] S401: The second network device sends a handover request message to the first network device.

[0205] Accordingly, the first network device receives the handover request message from the second network device. Before the second network device sends the handover request message to the first network device, the terminal device and the second network device may further execute S201 to S203 above. For details about the specific content of the handover request message, please refer to S204 above, which will not be repeated here.

[0206] S402: The first network device sends a handover request confirmation message to the second network device.

[0207] Correspondingly, the second network device receives the switching request confirmation message from the first network device.

[0208] Exemplarily, the first network device may also perform admission control before executing S402. The handover request confirmation message includes a transparent container, which is sent to the terminal device as content in the radio resource control reconfiguration message for the terminal device to perform the handover. For the specific content included in the handover request confirmation message, please refer to S207 above.

[0209] Exemplarily, the handover request confirmation message may include a first CSI configuration. Furthermore, exemplarily, the wireless resource control reconfiguration message sent by the second network device to the terminal device, i.e., S403, may include the first CSI configuration. The terminal device may measure the reference signal sent by the first network device according to the first CSI configuration, and report the first CSI report to the first network device. Exemplarily, the first CSI report is a CSI report measured by the terminal device based on the reference signal of the first network device. After the terminal device receives the handover command or accesses the target cell, it performs CSI measurement of the reference signal of the first network device. The terminal device measures the reference signal of the first network device according to the first CSI configuration to obtain a first CSI report. For the first CSI report, please refer to the relevant content in S304 above, which will not be repeated here.

[0210] S403: The second network device sends a radio resource control reconfiguration message to the terminal device.

[0211] Correspondingly, the terminal device receives a radio resource control reconfiguration message from the second network device.

[0212] In one possible implementation, the handover request confirmation message in S402 may further include indication information Y. The indication information Y is used to instruct the terminal device to send a second CSI report to the first network device. For the second CSI report, please refer to the relevant content in S301 above, which will not be repeated here. For example, since the first network device can learn through the handover request message that the handover process of the terminal device is DAPS handover, the first network device can generate and send indication information Y. Furthermore, the second network device can send a radio resource control reconfiguration message to the terminal device, that is, S403, and the radio resource control reconfiguration message may include indication information Y.

[0213] In another possible implementation, if the handover process is a DAPS handover, the second network device may generate and send indication information Y. The radio resource control reconfiguration message may include the indication information Y.

[0214] That is to say, the indication information Y may come from the first network device or from the second network device, and this application does not limit this. In addition, the indication information Y may also indicate that the second CSI report is carried by the random access message. Exemplarily, the indication information Y may include 1 bit, and the value of the 1 bit is 1, which indicates that the terminal device sends the second CSI report to the first network device; and the value of the 1 bit is 0, which indicates that the terminal device does not send the second CSI report to the first network device. Or exemplarily, the indication information Y may include 1 bit, and the value of the 1 bit is 0, which indicates that the terminal device sends the second CSI report to the first network device; and the value of the 1 bit is 1, which indicates that the terminal device does not send the second CSI report to the first network device. Or exemplarily, the indication information Y may include 1 bit, and the value of the 1 bit is true (true), which indicates that the terminal device sends the second CSI report to the first network device; and the value of the 1 bit is false (false), which indicates that the terminal device does not send the second CSI report to the first network device.

[0215] S404: The terminal device synchronizes to the target base station and sends a radio resource control reconfiguration completion message to the first network device.

[0216] Exemplarily, the terminal device completes synchronization to the target base station through a random access process.

[0217] Correspondingly, the first network device receives a radio resource control reconfiguration completion message from the terminal device.

[0218] The radio resource control reconfiguration complete message may be included in a random access message, for example, random access message 3.

[0219] In one possible implementation, if the handover process is a DAPS handover, the terminal device sends a second CSI report to the first network device. The radio resource control reconfiguration message also indicates whether the radio bearer of the target cell is configured as a DAPS bearer. When the bearer is configured as a DAPS bearer, the terminal device can determine, based on the indication, that the handover process of the terminal device is a DAPS handover.

[0220] In another possible implementation, the terminal device sends a second CSI report to the first network device according to the indication information Y.

[0221] The second CSI report may be sent separately, or may be included in the same message as the first CSI report and sent.

[0222] Optionally, the second CSI report can be sent within a preset time period after the terminal device accesses the first network device.

[0223] In a possible implementation, the first CSI report and / or the second CSI report may be carried by a random access message.

[0224] In another possible implementation, after the terminal device sends the radio resource control reconfiguration complete message to the first network device, before S405, the terminal device sends the first CSI report and / or the second CSI report to the first network device. For details, see the dotted line in Figure 4. For example, the second CSI report may be carried in an RRC message, UE assistance information (UAI), or a media access control element (MAC control element, MAC CE) message.

[0225] Optionally, the second CSI report can be sent once. For example, if the second CSI report is included in the random access message, it does not need to be sent again separately. For another example, if the second CSI report is not included in the random access message, the terminal device can send the second CSI report to the first network device after the random access message.

[0226] S405: The first network device determines, based on the received first CSI report and the received second CSI report, that values ​​of N parameters in the first CSI report are greater than or equal to values ​​of corresponding parameters in the second CSI report, where N is a positive integer.

[0227] Exemplarily, the N parameters include at least one of CQI, L1-RSRP, and L1-SINR.

[0228] S406: The first network device sends a handover completion message to the second network device.

[0229] Correspondingly, the second network device receives the switching completion message from the first network device.

[0230] S405 may refer to the above S305, and S406 may refer to the above S406. The repeated parts will not be repeated here.

[0231] As an optional solution, S405 can also be replaced by the first network device sending a display release instruction to the terminal device. Accordingly, the terminal device receives the display release instruction from the first network device, releases the second network device, and stops sending uplink data to the second network device and receiving downlink data.

[0232] Using the above method, the terminal device sends the first CSI report and the second CSI report to the first network device. The first CSI report and the second CSI report can be included in the same message or sent in two messages, and can be carried by a random access message or by other messages. If the first network device determines that the values ​​of the N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, the first network device sends a switching completion message to the second network device, and the second network device stops downlink data transmission. This can achieve data transmission through the second network device before the data rate on the first network device side is good and stable, so that the data transmission rate is maintained at a stable level during the switching period, avoiding a sudden drop in the data rate during the switching period, improving the switching performance, and ensuring a good user experience.

[0233] FIG5 exemplarily shows a possible flow diagram of a communication method provided in an embodiment of the present application. As shown in FIG5 , the method includes:

[0234] S501: The second network device sends a handover request message to the first network device.

[0235] Correspondingly, the first network device receives the switching request message from the second network device.

[0236] Before the second network device sends the switching request message to the first network device, the terminal device and the second network device may also execute the above S201 to S203. In addition, the specific content of the switching request message may also refer to the above S204, which will not be repeated here.

[0237] S502: The first network device sends a handover request confirmation message to the second network device.

[0238] Correspondingly, the second network device receives the switching request confirmation message from the first network device.

[0239] Exemplarily, the first network device may also perform admission control before executing S502. The handover request confirmation message includes a transparent container, which is sent to the terminal device as content in a radio resource control reconfiguration message for the terminal device to perform handover. For the specific content included in the handover request confirmation message, please refer to S207 above.

[0240] In one possible implementation, the handover request confirmation message in S502 may include a first CSI configuration. Furthermore, illustratively, the second network device may send a radio resource control reconfiguration message to the terminal device, i.e., S503, and the radio resource control reconfiguration message includes the first CSI configuration. The terminal device may measure the reference signal sent by the first network device according to the first CSI configuration, and report a first CSI report to the first network device. Exemplarily, the first CSI report is a CSI report measured by the terminal device based on the reference signal of the first network device. After the terminal device receives the handover command or accesses the target cell, it performs a CSI measurement of the reference signal of the first network device. The terminal device measures the reference signal of the first network device according to the first CSI configuration to obtain a first CSI report. For the first CSI report, please refer to the relevant content in S304 above, which will not be repeated here.

[0241] S503: The second network device sends a radio resource control reconfiguration message to the terminal device.

[0242] Correspondingly, the terminal device receives a radio resource control reconfiguration message from the second network device.

[0243] S504: The terminal device determines, based on the first CSI report and the second CSI report, that values ​​of N parameters in the first CSI report are greater than or equal to values ​​of corresponding parameters in the second CSI report, where N is a positive integer.

[0244] Exemplarily, the N parameters include at least one of CQI, L1-RSRP, and L1-SINR.

[0245] Exemplarily, if the handover process is a DAPS handover, the terminal device determines, based on the first CSI report and the second CSI report, that the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of corresponding parameters in the second CSI report. The radio resource control reconfiguration message further indicates whether the radio bearer of the target cell is configured as a DAPS bearer. When the indication bearer is configured as a DAPS bearer, the terminal device can determine, based on the indication, that the handover process of the terminal device is a DAPS handover.

[0246] For the first CSI report, please refer to S304 , and for the second CSI report, please refer to S301 , which will not be repeated here.

[0247] S505: The terminal device sends instruction information to the first network device.

[0248] Correspondingly, the first network device receives the indication information from the terminal device.

[0249] The indication information is used to instruct the first network device to send a switching completion message to the second network device, or the indication information is used to indicate that the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of corresponding parameters in the second CSI report, or the indication information is used to indicate that the channel quality indicated by the first CSI report is better than the channel quality indicated by the second CSI report, or the indication information is used to indicate that data transmission during the switching can be guaranteed only through transmission by the first network device, or the indication information is used to indicate that the channel quality indicated by the first CSI report can meet the data transmission requirements.

[0250] Exemplarily, the indication information may be carried through a radio resource control reconfiguration complete message or carried through UE assistance information, or the indication information may be sent through a separate RRC message or through a MAC CE.

[0251] S506: The first network device sends a handover completion message to the second network device.

[0252] It can be understood that, if the terminal device determines that the first CSI report measured based on the reference signal of the first network device meets the condition, that is, the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of corresponding parameters in the second CSI report, then the indication information is sent to the first network device. If the terminal device determines that the first CSI report measured based on the reference signal of the first network device does not meet the condition, that is, there are M parameters in the first CSI report that have values ​​less than the values ​​of corresponding parameters in the second CSI report, where the N references include M parameters, then the indication information is not sent to the first network device.

[0253] For example, assuming that N parameters include CQI and L1-RSRP, a first CSI report measured by the terminal device based on the reference signal of the first network device is recorded as the first CSI report 1. If the terminal device determines that the value of CQI in the first CSI report 1 is less than the value of CQI in the second CSI report, and the value of L1-RSRP in the first CSI report 1 is greater than the value of L1-RSRP in the second CSI report, the terminal device does not send an indication message, and the first network device does not send a switching completion message to the second network device. Therefore, the second network device remains connected to the terminal device. Furthermore, the terminal device measures the reference signal sent by the first network device at the next configured CSI measurement opportunity or periodically to obtain a first CSI report 2. The terminal device determines whether the CQI value in the first CSI report 2 is greater than or equal to the CQI value in the second CSI report, and whether the L1-RSRP value in the second CSI report 2 is greater than or equal to the L1-RSRP value in the second CSI report. If the CQI value in the second CSI report 2 is greater than or equal to the CQI value in the second CSI report, and the L1-RSRP value in the second CSI report 2 is greater than or equal to the L1-RSRP value in the second CSI report, the terminal device sends indication information to the first network device, and the first network device sends a switching completion message to the second network device. Otherwise, the terminal device measures the reference signal sent by the first network device at the next configured CSI measurement opportunity or periodically until the CQI value in the first CSI report X is greater than or equal to the CQI value in the second CSI report, and the L1-RSRP value in the first CSI report X is greater than or equal to the L1-RSRP value in the second CSI report, then the terminal device sends indication information to the first network device, and the first network device sends a switching completion message to the second network device according to the indication information, where X is a positive integer.

[0254] For another example, assuming that the N parameters include CQI, the terminal device measures a first CSI report based on the reference signal of the first network device, which is recorded as the first CSI report a. If the terminal device determines that the CQI value in the first CSI report a is greater than the CQI value in the second CSI report, the terminal device sends an indication to the first network device, and the first network device sends a handover complete message to the second network device based on the indication.

[0255] In addition, as an optional solution, the indication information may further instruct the first network device to send a display release indication to the terminal device. In this case, S506 may be replaced by the first network device sending a display release indication to the terminal device. Accordingly, the terminal device receives the display release indication from the first network device, releases the second network device, and stops sending uplink data to the second network device and receiving downlink data.

[0256] Using the above method, the first network device does not need to obtain the first CSI report and the second CSI report, thereby saving signaling overhead between network devices. When the terminal device determines that the values ​​of the N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, it sends an indication to the first network device. The first network device sends a handover completion message to the second network device based on the indication, and the second network device then stops downlink data transmission. This allows data transmission through the second network device before the data rate on the first network device side is good and stable, maintaining a high data transmission rate during the handover period, avoiding a sudden drop in the data rate during the handover, improving handover performance, and ensuring a good user experience.

[0257] FIG6 exemplarily shows a possible flow diagram of a communication method provided in an embodiment of the present application. As shown in FIG6 , the method includes:

[0258] S601: The second network device sends a handover request message to the first network device.

[0259] Correspondingly, the first network device receives the switching request message from the second network device.

[0260] Before the second network device sends the switching request message to the first network device, the terminal device and the second network device may also execute S201 to S203 above. In addition, for the specific content of the switching request message, please refer to S204 above, which will not be repeated here.

[0261] S602: The first network device sends third CSI configuration information and fourth CSI configuration information to the second network device.

[0262] Correspondingly, the second network device receives the third CSI configuration information and the fourth CSI configuration information from the first network device.

[0263] Exemplarily, after receiving the handover request message, the first network device may send a handover request confirmation message to the second network device. The handover request confirmation message may include the third CSI configuration information and the fourth CSI configuration information.

[0264] Among them, in addition to sending the third CSI configuration information to the second network device, the first network device also sends the fourth CSI configuration information, that is, the first network device additionally configures the fourth CSI configuration information for the terminal device in addition to the third CSI configuration information, so that the terminal device performs the measurement of the reference signal of the first network and the reporting of the CSI report at a higher frequency, so that the network can quickly obtain the CSI report of the terminal device, and then can timely adjust the MCS according to the received CSI report, and quickly climb the MCS. Among them, this application does not limit the resource type configuration of the reference signal configured by the fourth CSI configuration information, nor does it limit the reporting type of the fourth CSI report configured by the fourth CSI configuration information. The fourth CSI report is obtained by the terminal device based on the reference signal measurement configured by the fourth CSI configuration information.

[0265] Optionally, the fourth CSI configuration may be effective only during switching. For example, when the terminal device accesses the first network device or the terminal device receives a display release indication from the first network device, the display release indication is used to indicate the release of the source base station, then the fourth CSI configuration is released or the fourth CSI configuration is invalid, and then the terminal device no longer performs measurement and measurement reporting based on the fourth CSI configuration.

[0266] Furthermore, in a possible implementation, the reporting period of the third CSI report configured by the third CSI configuration information is greater than the reporting period of the fourth CSI report configured by the fourth CSI configuration information; or, the reporting type of the fourth CSI report configured by the fourth CSI configuration information is dynamic reporting, and the reporting type of the fourth CSI report configured by the third CSI configuration information is periodic reporting. Dynamic reporting can be non-periodic reporting or semi-continuous reporting. The third CSI report is obtained by the terminal device based on the reference signal measurement configured by the third CSI configuration information, and the fourth CSI report is obtained by the terminal device based on the reference signal measurement configured by the fourth CSI configuration information.

[0267] In one implementation, the first network device generates third CSI configuration information and fourth CSI configuration information, and then the first network device sends the third CSI configuration information and the fourth CSI configuration information to the second network device.

[0268] In another implementation, the second network device negotiates with the first network device so that the second network device generates the third CSI configuration information and the fourth CSI configuration information. In this case, step S602 is optional.

[0269] S603: The second network device sends third CSI configuration information and fourth CSI configuration information to the terminal device.

[0270] Correspondingly, the terminal device receives the third CSI configuration information and the fourth CSI configuration information from the second network device.

[0271] Exemplarily, the second network device may send a radio resource control reconfiguration message to the terminal device, where the radio resource control reconfiguration message includes the third CSI configuration information and the fourth CSI configuration information.

[0272] S604: The terminal device measures the reference signal configured by the third CSI configuration information according to the third CSI configuration information, obtains a third CSI report, and sends the third CSI report to the first network device; the terminal device measures the reference signal configured by the fourth CSI configuration information according to the fourth CSI configuration information, obtains a fourth CSI report, and sends the fourth CSI report to the first network device.

[0273] Exemplarily, after the terminal device receives a handover command or accesses a target cell, the terminal device executes S604.

[0274] In one possible implementation, when the reporting period of the third CSI report configured by the third CSI configuration information is greater than the reporting period of the fourth CSI report configured by the fourth CSI configuration information, the first network device can receive the fourth CSI report first, that is, receive the fourth CSI report earlier than the third CSI report, thereby enabling the first network device to obtain the CSI report earlier, so that the MCS can be adjusted in time according to the received CSI report.

[0275] In another possible implementation, the reporting type of the fourth CSI report configured in the fourth CSI configuration information is dynamic reporting. If the dynamic reporting is non-periodic reporting, the terminal device can report the fourth CSI report more timely, so that the first network device can obtain the CSI report earlier.

[0276] In addition, in combination with the embodiments shown in FIG. 3 and FIG. 4 , the first network device may receive a second CSI report from the terminal device or the second network device. For details about the second CSI report, reference may be made to S301 above.

[0277] In one possible implementation, values ​​of N parameters in at least one of the third CSI report and the fourth CSI report are greater than or equal to values ​​of corresponding parameters in the second CSI report, and the first network device sends a handover complete message to the second network device, where N is a positive integer. Exemplarily, the N parameters include at least one of CQI, L1-RSRP, and L1-SINR.

[0278] Exemplarily, the first network device may receive the fourth CSI report, and if the values ​​of the N parameters in the fourth CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, the first network device sends a handover complete message to the second network device.

[0279] Exemplarily, the first network device receives a third CSI report and a fourth CSI report. If the values ​​of M parameters in the fourth CSI report are less than the values ​​of corresponding parameters in the second CSI report, and the N parameters include M parameters, but the values ​​of N parameters in the third CSI report are greater than or equal to the values ​​of corresponding parameters in the second CSI report, the first network device sends a switching completion message to the second network device, where M is a positive integer less than or equal to N.

[0280] Exemplarily, the first network device receives the third CSI report, and if the values ​​of N parameters in the third CSI report are greater than or equal to the values ​​of corresponding parameters in the second CSI report, the first network device sends a handover complete message to the second network device.

[0281] With the above design, the first network device additionally configures the terminal device with the fourth CSI configuration information in addition to the third CSI configuration information, so that the terminal device can perform the measurement of the reference signal of the first network device and the reporting of the corresponding CSI report at a higher frequency, that is, the terminal device can report the third CSI report and the fourth CSI report, so that the network can quickly obtain the CSI report reported by the terminal device, and then can realize timely adjustment of the MCS according to the received CSI report, as well as rapid climbing of the MCS.

[0282] FIG7 exemplarily shows a possible flow diagram of a communication method provided in an embodiment of the present application. As shown in FIG7 , the method includes:

[0283] S701: The first network device sends a handover completion message to the second network device.

[0284] Correspondingly, the second network device receives the switching completion message from the first network device.

[0285] S702: The second network device stops downlink data transmission if it determines that at least one of the following conditions is met.

[0286] Condition 1: The second network device receives the handover completion message and starts timing until the first duration is reached.

[0287] For example, upon receiving the handover completion message, the second network device starts a timer. When the timer expires, the second network device stops downlink data transmission. Optionally, the timing duration of the timer is predefined by a network configuration or protocol. For example, the timing duration of the timer can be configured by the second network device or the first network device.

[0288] Condition 2: The second network device receives indication information Z.

[0289] Exemplarily, the terminal device determines, based on the first CSI report and the second CSI report, that the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, where N is a positive integer. The terminal device sends indication information Z to the second network device. The indication information Z is used to indicate that the values ​​of the N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report.

[0290] The N parameters include at least one of CQI, L1-RSRP, and L1-SINR. For the first CSI report, please refer to S304, and for the second CSI report, please refer to S301, which will not be repeated here.

[0291] Condition 3: The second network device determines that the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of corresponding parameters in the second CSI report, where N is a positive integer. The N parameters include at least one of CQI, L1-RSRP, and L1-SINR.

[0292] Exemplarily, a terminal device sends a first CSI report to a second network device. The second network device receives the first CSI report from the terminal device, compares the values ​​of N parameters in the first CSI report with the values ​​of corresponding parameters in the second CSI report, and if the values ​​of the N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, the second network device stops downlink data transmission. Exemplarily, assuming that the N parameters in the CSI report include a CQI, if the value of the CQI in the first CSI report is greater than or equal to the value of the CQI in the second CSI report, the second network device stops downlink data transmission.

[0293] By adopting the above method, after the second network device receives the switching completion message from the first network device, it does not stop the downlink data transmission immediately, but stops the downlink data transmission when certain conditions are met. This can achieve data transmission through the second network device before the data rate on the first network device side is good and stable, so that the data transmission rate is maintained stable during the switching period, avoiding a sudden drop in the data rate during the switching period, improving the switching performance, and ensuring a good user experience.

[0294] FIG8 exemplarily shows a possible flow diagram of a communication method provided in an embodiment of the present application. As shown in FIG8 , the method includes:

[0295] S801: The first network device receives a second CSI report.

[0296] For the second CSI report, please refer to S301 and will not be repeated here.

[0297] In a possible implementation, the second network device sends a handover request message to the first network device. The handover request message may include the second CSI report.

[0298] In another possible implementation, the second network device may send the second CSI report to the first network device after the handover request message. For example, the second CSI report may be carried in a message between network devices, that is, the second CSI report may not be carried in the handover request message.

[0299] In yet another possible implementation, the terminal device sends a second CSI report to the first network device.

[0300] In one example, if the handover process is a DAPS handover, the terminal device sends a second CSI report to the first network device. The radio resource control reconfiguration message sent by the second network device to the terminal device also indicates whether the radio bearer of the target cell is configured as a DAPS bearer. When the bearer is configured as a DAPS bearer, the terminal device can determine, based on the indication, that the handover process of the terminal device is a DAPS handover.

[0301] In another example, the terminal device sends a second CSI report to the first network device according to the indication information Y. The indication information Y can refer to the above S403 and will not be described in detail here.

[0302] S802: The first network device adjusts the MCS according to the second CSI report.

[0303] Exemplarily, the first network device adjusts the initial value or initial index of the MCS of the first network device according to the second CSI report, that is, adjusts the MCS used by the first network device to communicate with the terminal device.

[0304] S803: Optionally, the first network device sends indication information Q to the terminal device, where the indication information Q is used to indicate the adjusted MCS.

[0305] Correspondingly, the terminal device receives indication information Q from the first network device.

[0306] With the above design, the first network device can adjust the MCS according to the second CSI report, reduce the adjustment delay of the MCS of the target base station, ensure the use of appropriate scheduling information during DAPS, and thereby ensure that the data transmission rate is stable during switching, avoid a sudden drop in data rate during switching, improve switching performance, and ensure a good user experience.

[0307] FIG9 exemplarily shows a possible flow diagram of a communication method provided in an embodiment of the present application. As shown in FIG9 , the method includes:

[0308] S901: A first network device receives first information, where the first information includes MCS information and / or data rate information.

[0309] In a possible implementation, the second network device sends the first information to the first network device. Correspondingly, the first network device receives the first information from the second network device.

[0310] In an example, a first network device receives a handover request message from a second network device, where the handover request message includes first information.

[0311] In another example, the first information is included in a handover preparation message. The handover preparation message is a message from the first network device to the second network device or a message from the CU to the DU. Exemplarily, the handover preparation message is included in the handover request message.

[0312] In another example, the first information may be carried by a message between network devices, that is, the first information may not be carried by a handover request message.

[0313] Exemplarily, the DU of the second network device sends the first information to the CU of the second network device, and the CU of the second network device sends the first information to the CU of the first network device. Optionally, the CU of the first network device sends the first information to the DU of the first network device.

[0314] In one possible implementation, the terminal device sends the first information to the first network device. Accordingly, the first network device receives the first information from the terminal device. Exemplarily, the terminal device sends the first information to the first network device, and the first information may be carried in an RRC message, UE assistance information, or MAC CE. Exemplarily, after receiving an RRC reconfiguration message (S207) from the second network device, the terminal device sends the first information to the first network device, or the first information may be carried in an RRC reconfiguration complete message (S209).

[0315] Optionally, before S901 , the terminal device, the first network device and the second network device may further perform one or more steps of S201 - S206 .

[0316] (1)MCS information

[0317] The MCS information may be understood as expected or recommended MCS information.

[0318] Optionally, the expected or recommended MCS information can be determined based on the MCS information of the second network device. Exemplarily, the MCS information can be the MCS information of the second network device, or the MCS information of the cell under the second network device. Alternatively, the MCS information can also be the MCS information of the terminal device under the second network device or the MCS information of the terminal device under the second network device. For example, the second network device is a source base station, and the MCS information can be the MCS information of the source cell. Alternatively, the MCS information can be the MCS information of the terminal device under the source cell or the MCS information when the terminal device is connected to the source cell.

[0319] Exemplarily, the MCS information may include at least one of an MCS index, an MCS value, and an MCS threshold.

[0320] For example, when the MCS information includes an MCS index, the MCS information may also include an MCS table index. The first network device may determine an MCS table of the corresponding index from multiple MCS tables based on the MCS table index, and further determine the MCS of the corresponding index based on the MCS index and the determined MCS table. In addition, the MCS information may not include an MCS table index, but only include an MCS index. In this case, the first network device may determine the MCS of the corresponding index based on the MCS index and a default MCS table.

[0321] For another example, when the MCS information includes an MCS value, the MCS value may include but is not limited to at least one of the values ​​of the following parameters: modulation mode, modulation order, spectrum efficiency, and the product of the coding rate and 1024.

[0322] For another example, when the MCS information includes an MCS threshold, the present application does not limit the specific method for determining the MCS threshold. For example, the MCS threshold may be a threshold of an MCS index, or a threshold of a parameter that the MCS may include.

[0323] Exemplarily, the MCS information may be determined in the following manner, but not limited to:

[0324] Method i: The MCS information can be determined based on the MCS last used in communication between the second network device and the terminal device before the second network device sends the first information to the first network device. For example, the index or value of the last used MCS is used as the MCS information. Alternatively, the MCS threshold is determined based on the last used MCS.

[0325] Method ii: The MCS information can be determined based on the MCS last used in the communication between the second network device and the terminal device before the second network device sends a switching command to the terminal device, or can be determined based on the MCS last used in the communication between the second network device and the terminal device before the terminal device receives the switching command.

[0326] Method iii: The MCS information can be determined based on multiple MCSs used in communications between the terminal device and the second network device over a period of time. Exemplarily, the period of time here can be a preset duration. For example, the period of time here can be a period of time before the terminal device receives the radio resource reconfiguration message, or a period of time before the second network device sends a handover request message to the first network device.

[0327] For example, the average value of the parameter values ​​of multiple MCSs within a period of time can be used as the MCS information, or the rounded result of the average value of the indexes of multiple MCSs within a period of time can be used as the MCS information, or the MCS threshold can be determined based on multiple MCSs within a period of time.

[0328] (2) Data rate information

[0329] Exemplarily, the data rate information may be understood as expected or recommended data rate information.

[0330] Exemplarily, the data rate information may be data rate information of the second network device, or data rate information of a cell under the second network device, or data rate information of the terminal device under the second network device, or data rate information of the terminal device under the second network device. For example, the second network device is a source base station, and the data rate information may be data rate information of the source cell, or data rate information of the terminal device under the source cell, or data rate information when the terminal device is connected to the source cell.

[0331] The data rate information includes at least one of a data rate, a data rate threshold, a data rate range, or other information that can characterize the data rate. For example, the unit of the data rate may be Mbps.

[0332] The data rate information may be determined by, but is not limited to, the following methods:

[0333] Mode i: The data rate information can be determined based on the data rate of communication between the second network device and the terminal device that is most recently measured before the second network device sends the first information to the first network device.

[0334] For example, a data rate threshold or a data rate range is determined based on the most recently measured data rate, or the most recently measured data rate is directly used as the data rate information.

[0335] Method ii: The data rate information can be determined based on the data rate of communication between the second network device and the terminal device that was last measured before the second network device sends a switching command to the terminal device, or can be determined based on the data rate of communication between the second network device and the terminal device that was last measured before the terminal device receives the switching command.

[0336] Method iii: The data rate information may be determined based on the data rate over a period of time. The period of time here may be a preset duration. For example, the period of time here may be a period of time before the terminal device receives the radio resource reconfiguration message, or a period of time before the second network device sends a handover request message to the first network device.

[0337] For example, the average value of the data rate within a period of time may be used as the data rate information, or the data rate threshold or the data rate range may be determined based on the average value of the data rate within a period of time.

[0338] S902: The terminal device receives an RRC reconfiguration message from the second network device.

[0339] Correspondingly, the second network device sends an RRC reconfiguration message to the terminal device. The RRC reconfiguration message instructs the terminal to perform a handover. Exemplarily, the RRC reconfiguration message is a handover command.

[0340] Exemplarily, the RRC reconfiguration message further indicates whether the radio bearer of the target cell is configured as a DAPS bearer. When the bearer is configured as a DAPS bearer, the terminal device can determine that the handover process of the terminal device is a DAPS handover according to the indication.

[0341] It should be understood that the order of steps S902 and S901 is not limited. S901 can be performed first and then S902, or S902 can be performed first and then S901.

[0342] S903: The first network device receives a first CSI report from the terminal device.

[0343] Exemplarily, the first network device determines second information according to the first CSI report, where the second information includes the MCS or data rate of the first network device.

[0344] Exemplarily, a first network device receives a first CSI report from a terminal device. The terminal device determines an MCS or data rate of the first network device based on the first CSI report. The MCS of the first network device refers to the MCS used for communication between the first network device and the terminal device. The data rate of the first network device refers to the data rate at which the first network device communicates with the terminal device.

[0345] In one possible implementation, the radio resource control reconfiguration message includes a first CSI configuration. The terminal device can measure the reference signal sent by the first network device according to the first CSI configuration, and report a first CSI report to the first network device. Exemplarily, the first CSI report is a CSI report measured by the terminal device based on the reference signal of the first network device. After the terminal device receives a handover command or accesses the target cell, it performs a CSI measurement of the reference signal of the first network device. The terminal device measures the reference signal of the first network device according to the first CSI configuration to obtain a first CSI report. For the first CSI report, please refer to the relevant content in S304 above, which will not be repeated here.

[0346] Exemplarily, the MCS of the first network device may also be the MCS of the cell under the first network device. Alternatively, the MCS of the first network device may also be the MCS of the terminal device under the first network device or the MCS of the terminal device under the first network device. For example, if the first network device is a target base station, the MCS of the first network device may be the MCS of the target cell. Alternatively, the MCS of the first network device may be the MCS information of the terminal device under the target cell or the MCS of the terminal device when connected to the target cell.

[0347] Exemplarily, the data rate of the first network device may also be the data rate of the cell under the first network device. Alternatively, the data rate of the first network device may also be the data rate of the terminal device under the first network device, or the data rate of the terminal device under the first network device. For example, if the first network device is a target base station, the data rate of the first network device may be the data rate of the target cell, or the data rate of the first network device may be the data rate of the terminal device under the target cell, or the data rate of the terminal device when connected to the target cell.

[0348] In one possible implementation, the DU of the first network device sends the MCS or data rate of the first network device to the CU of the first network device, wherein the MCS or data rate of the first network device may be carried by an F1 application protocol (F1AP) message.

[0349] S904A: If the preset condition X is met, the first network device sends a handover completion message to the second network device.

[0350] For example, if it is determined based on the first information and the second information that the preset condition X is satisfied, the first network device sends a handover completion message to the second network device. In one possible design, if the preset condition X is satisfied, the first network device sends a handover completion message to the second network device. Accordingly, the second network device receives the handover completion message from the first network device. Optionally, upon receiving the handover completion message from the first network device, the second network device stops downlink data transmission.

[0351] S904B: If the preset condition X is met, the first network device instructs the second network device to stop downlink data transmission.

[0352] Exemplarily, if it is determined according to the first information and the second information that the preset condition X is satisfied, the first network device sends a handover completion message to the second network device.

[0353] In one possible design, if a preset condition X is met, the first network device instructs the second network device to stop downlink data transmission. Accordingly, the second network device receives the instruction to stop downlink data transmission from the first network device. Optionally, the second network device receives a handover completion message from the first network device, and the second network device does not stop downlink data transmission. After the second network device receives the instruction to stop downlink transmission from the first network device, the second network device stops downlink data transmission.

[0354] S904C: If the preset condition X is met, the first network device sends a display release indication to the terminal device.

[0355] Exemplarily, if it is determined according to the first information and the second information that the preset condition X is satisfied, the first network device sends a handover completion message to the second network device.

[0356] In one possible design, if the preset condition X is met, the first network device sends a display release indication to the terminal device. Accordingly, the terminal device receives the display release indication from the first network device, releases the second network device, and stops sending uplink data to the second network device and receiving downlink data.

[0357] It can be understood that the first network device can perform one or more steps in the above S904A, S904B or S904C.

[0358] If the first information includes MCS information and the second information includes the MCS of the first network device, the preset condition X may be that the MCS in the MCS information in the first information is greater than or equal to the MCS of the first network device in the second information; or, if the first information includes data rate information and the second information includes the data rate of the first network device, the preset condition X may be that the data rate in the data rate information in the first information is greater than or equal to the data rate of the first network device in the second information.

[0359] The first network device determines that the preset condition X is satisfied based on the first information and the second information. Alternatively, if the first information includes MCS information and the second information includes the MCS of the first network device, the determination that the preset condition X is satisfied is based on the MCS of the first network device in the second information and the MCS information in the first information; or, if the first information includes data rate information and the second information includes the data rate of the first network device, the determination that the preset condition X is satisfied is based on the data rate of the first network device in the second information and the data rate information in the first information.

[0360] Specifically, it may include but is not limited to the following situations:

[0361] Case a: If the first information includes MCS information, the MCS information includes the index of the MCS, the second information includes the MCS of the first network device, and the preset condition X is satisfied or it is determined based on the first information and the second information that the preset condition X is satisfied, it can be understood that the index of the MCS of the first network device is greater than or equal to the index of the MCS in the first information.

[0362] Case b: If the first information includes MCS information, the MCS information includes the MCS value, the second information includes the MCS of the first network device, and the preset condition X is satisfied or it is determined based on the first information and the second information that the preset condition X is satisfied, it can be understood that the values ​​of some or all parameters in the MCS of the first network device are determined to be greater than or equal to the values ​​of the corresponding parameters in the MCS in the first information.

[0363] Case c: If the first information includes MCS information, the MCS information includes an MCS threshold, and the second information includes the MCS of the first network device, determining whether the preset condition X is satisfied depends on the specific form of the MCS threshold, and reference may be made to the above cases a and b.

[0364] Case d: If the first information includes data rate information, the data rate information includes a data rate value (or threshold), and the second information includes the data rate of the first network device, and the preset condition X is satisfied or it is determined based on the first information and the second information that the preset condition X is satisfied, it can be understood that the data rate of the first network device is determined to be greater than or equal to the data rate (or threshold) in the first information.

[0365] Case e: If the first information includes data rate information, the data rate information includes a data rate range, and the second information includes the data rate of the first network device, and the preset condition X is satisfied or it is determined based on the first information and the second information that the preset condition X is satisfied, it can be understood that the data rate of the first network device is determined to fall within the data rate range.

[0366] It can be understood that the above situations are only examples and are not limitations of this application. In addition, the above situations can be combined with each other. For example, if the index of the MCS of the first network device is greater than or equal to the index of the MCS in the first information, and the data rate of the first network device falls within the data rate range, it is determined that the preset condition X is met.

[0367] It should be understood that steps S902 and S903 in FIG. 9 are optional, that is, in certain circumstances, S902 and / or S903 may not be performed.

[0368] Using the above method, the first network device obtains the first information and determines the second information. If the first network device determines that the preset condition X is satisfied based on the first information and the second information, the first network device sends a handover completion message to the second network device, or the second network device instructs the first network device to stop downlink data transmission, or the second network device sends a display release indication to the terminal device. This allows data transmission to be performed through the second network device before the data rate on the first network device side is good and stable, thereby maintaining a stable data transmission rate during the handover, avoiding a sudden drop in the data rate during the handover, improving handover performance, and ensuring a good user experience.

[0369] In one implementation, when only step S901 is executed, the above method is adopted, and the first network device obtains the first information. The first network device refers to the first information and determines to send a switching completion message to the second network device, or the second network device instructs the first network device to stop downlink data transmission, or the second network device sends a display release indication to the terminal device. Therefore, before the data rate on the first network device side is good and stable, data transmission can be performed through the second network device and the first network device, so that the data transmission rate is maintained stable during the switching, the data rate is avoided from dropping suddenly during the switching, the switching performance is improved, and a good user experience is guaranteed.

[0370] FIG10 exemplarily shows a possible flow diagram of a communication method provided in an embodiment of the present application. As shown in FIG10 , the method includes:

[0371] S1001: The terminal device receives an RRC reconfiguration message from a second network device.

[0372] Correspondingly, the second network device sends an RRC reconfiguration message to the terminal device.

[0373] Exemplarily, the RRC reconfiguration message further indicates whether the radio bearer of the target cell is configured as a DAPS bearer. When the bearer is configured as a DAPS bearer, the terminal device can determine that the handover process of the terminal device is a DAPS handover according to the indication.

[0374] Optionally, before S1001, the terminal device, the first network device and the second network device may further perform one or more steps of S201-S206.

[0375] S1002: The terminal device determines the first information and the second information.

[0376] For example, if the handover process is a DAPS handover, the terminal device determines the first information and the second information. For details of the first information, refer to S902 above, and for details of the second information, refer to S903 above.

[0377] It should be understood that step S1002 is optional.

[0378] S1003: The terminal device sends indication information X to the first network device. Correspondingly, the first network device receives the indication information X from the terminal device.

[0379] For example, if it is determined based on the first information and the second information that the preset condition X is met, the terminal device sends indication information X to the first network device.

[0380] Regarding how to determine whether the preset condition X is satisfied according to the first information and the second information, reference may be made to the above 903 .

[0381] Exemplarily, the indication information X is used to instruct the first network device to stop the downlink transmission of the second network device or to instruct the first network device to send a switching completion message to the second network device, or to instruct the first network device to release the second network device, or to instruct the first network device to send a display release indication to the terminal device.

[0382] Exemplarily, the indication information X is used to indicate that the terminal device believes that the required data rate or MCS can be provided during the handover only through the first network device.

[0383] In one possible design, if the first information includes data rate information, the second information includes the data rate of the first network device, and the terminal device determines that the preset condition X is satisfied based on the data rate of the first network device in the second information and the data rate information in the first information, then the indication information X can also be used to indicate that only transmission through the first network device can ensure that the data rate during the switching period is stable or does not decrease or provides the required data rate, or to indicate that only transmission through the first network device can ensure the data rate during the switching period, or to indicate that the data rate transmitted under the first network device reaches an expected value or reaches a threshold, or to indicate that the data rate of the first network device is higher than the data rate of the second network device. Exemplarily, when the indication information X is used to indicate that the data rate of the first network device is higher than the data rate of the second network device, the data rate of the second network device may be the data rate most recently measured before the terminal device receives the RRC reconfiguration message.

[0384] In another possible design, if the first information includes MCS information, and the second information includes the MCS of the first network device, and the terminal device determines that a preset condition X is satisfied based on the MCS of the first network device in the second information and the MCS information in the first information, then the indication information X may also be used to indicate that the MCS of the first network device has reached an expected value or a threshold, or to indicate that the MCS of the first network device is higher than the MCS of the second network device. For example, when the indication information X is used to indicate that the MCS of the first network device is higher than the MCS of the second network device, the MCS of the second network device may be the MCS most recently used before the terminal device receives the RRC reconfiguration message.

[0385] Exemplarily, the indication information may be carried in an RRC message, UE assistance information, or MAC CE.

[0386] In one implementation, whether the terminal device supports sending indication information X during DPAS switching is a capability of the terminal device. For example, if the terminal device supports sending indication information X during DPAS switching, the terminal device reports the support to the second network device via a terminal capability reporting message. For example, if the second network device configures signaling or information elements related to sending indication information X during DPAS switching in an RRC reconfiguration message sent by the network device to the terminal device, the terminal device can send indication information X to the first network device during DPAS switching.

[0387] S1004A: The first network device sends a handover completion message to the second network device.

[0388] In one possible design, the first network device sends a handover completion message to the second network device based on the indication information X, or the first network device receives the indication information X and sends a handover completion message to the second network device. Accordingly, the second network device receives the handover completion message from the first network device. Optionally, the second network device stops downlink data transmission after receiving the handover completion message from the first network device.

[0389] S1004B: The first network device instructs the second network device to stop downlink data transmission.

[0390] In one possible design, the first network device instructs the second network device to stop downlink data transmission based on the indication information X, or the first network device receives the indication information X and instructs the second network device to stop downlink data transmission. Accordingly, the second network device receives the instruction to stop downlink data transmission from the first network device. Optionally, the second network device receives a switching completion message from the first network device, and the second network device does not stop downlink data transmission. After the second network device receives the instruction to stop downlink transmission from the first network device, the second network device stops downlink data transmission.

[0391] S1004C: The first network device sends a display release indication to the terminal device.

[0392] In one possible design, the first network device sends a display release indication to the UE according to the indication information X, or the first network device receives the indication information X, and the first network device sends a display release indication to the terminal device. Accordingly, the terminal device receives the display release indication from the first network device, releases the second network device, and stops sending uplink data to the second network device and receiving downlink data.

[0393] It is understandable that the first network device may execute one or more steps in S1004A, S1004B or S1004C above.

[0394] Using the above method, the terminal device determines the first information and the second information. If the terminal device determines that the preset condition X is satisfied based on the first information and the second information, the terminal device sends the indication information X to the first network device, and the first network device then sends a handover completion message to the second network device, or the second network device instructs the first network device to stop downlink data transmission, or the second network device sends a display release indication to the terminal device. This allows data transmission through the second network device before the data rate on the first network device side is good and stable, thereby maintaining a stable data transmission rate during the handover, avoiding a sudden drop in the data rate during the handover, improving handover performance, and ensuring a good user experience.

[0395] In one implementation, without executing step S1002, the above method is adopted, and the terminal device sends an indication information X to the first network device, and then the first network device sends a switching completion message to the second network device, or the second network device instructs the first network device to stop downlink data transmission, or the second network device sends a display release indication to the terminal device, thereby achieving data transmission through the second network device before the data rate on the first network device side is good and stable, so that the data transmission rate is maintained stable during the switching period, avoiding a sudden drop in the data rate during the switching period, improving the switching performance, and ensuring a good user experience.

[0396] The steps in the method of the embodiment of the present application can be adjusted in order, merged and deleted according to actual needs. The steps of each embodiment can be partially executed (for example, the terminal device may not execute the steps performed by the terminal device in the above embodiment). The execution order of different steps can be changed. The embodiments described herein can be combined with other embodiments, and different embodiments can also be combined with each other. The different steps of the different embodiments of this document can also be combined. Any step in the method of the embodiment of the present application can be optional in certain situations or scenarios.

[0397] The modules / units in the device of the embodiment of the present application can be merged, divided and deleted according to actual needs.

[0398] 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 appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0399] The terms "first", "second", "third", "fourth", etc. (if any) in the embodiments of the present application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0400] In the embodiments of the present application, "include" can be an inclusion relationship or an equality relationship. For example, A includes B, which means that A includes B and can also include other content, or A and B are the same content.

[0401] In the description of this application, unless otherwise specified, " / " indicates that the objects associated with each other are in an "or" relationship. For example, A / B can represent A or B. "And / or" in this application is only a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. In addition, in the description of this application, unless otherwise specified, "multiple" means two or more than two. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple. In addition, in order to facilitate the clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" are used to distinguish between identical or similar items with basically the same functions and effects. Those skilled in the art can understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit them to be different.

[0402] It is understood that in order to implement the functions in the above embodiments, the network devices and terminal devices include hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily appreciate that, in combination with the units and method steps of each example described in the embodiments disclosed in this application, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in hardware or in a manner driven by computer software depends on the specific application scenario and design constraints of the technical solution.

[0403] Figures 11 and 12 are schematic diagrams of the structures of possible communication devices provided in embodiments of the present application. These communication devices can be used to implement the functions of the terminal device or network device in the above-mentioned method embodiments, thereby also achieving the beneficial effects possessed by the above-mentioned method embodiments. In the embodiments of the present application, the communication device can be one of the terminal devices 120a-120j shown in Figure 1, or it can be the base station 110a or 110b shown in Figure 1, or it can be a module (such as a chip) applied to the terminal device or base station.

[0404] As shown in Figure 11, the communication device 1100 includes a processing unit 1110 and a transceiver unit 1120. The communication device 1100 is used to implement the functions of the terminal device or the first network device in the method embodiments shown in Figures 3 to 6 above.

[0405] When the communication device 1100 is used to implement the function of the first network device in the method embodiment shown in FIG3 or 4:

[0406] The processing unit 1110 calls the transceiver unit 1120 to execute: receiving a switching request message from the second network device; the first network device obtains a first CSI report and a second CSI report, where the first CSI report is a CSI report measured by the terminal device based on the reference signal of the first network device, and the second CSI report is a CSI report measured by the terminal device based on the reference signal of the second network device; if the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, sending a switching completion message to the second network device, where N is a positive integer.

[0407] In one possible design, the transceiver unit 1120 is used to receive the second CSI report from the second network device or from the terminal device.

[0408] In one possible design, the transceiver unit 1120 is used to receive the switching request message from the second network device, and the switching request message includes the second CSI report.

[0409] In one possible design, the transceiver unit 1120 is used to receive a random access message from the terminal device, where the random access message includes the second CSI report.

[0410] In one possible design, the transceiver unit 1120 is used to receive a first CSI report from the terminal device.

[0411] In one possible design, the first CSI report is carried via a random access message.

[0412] In one possible design, the N parameters include at least one of CQI, L1-RSRP, and L1-SINR.

[0413] When the communication device 1100 is used to implement the functions of the terminal device in the method embodiment shown in Figure 3 or 4: the processing unit 1110 calls the transceiver unit 1120 to execute: receiving a switching command from the second network device, the switching command indicating that the switching process of the terminal device is DAPS switching; sending a second CSI report to the first network device; the second CSI report is a CSI report measured by the terminal device based on the reference signal of the second network device.

[0414] In one possible design, the second CSI report is carried via a random access message.

[0415] When the communication device 1100 is used to implement the function of the first network device in the method embodiment shown in FIG5 :

[0416] The processing unit 1110 calls the transceiver unit 1120 to execute: receiving a switching request message from the second network device; the first network device receives an indication message from the terminal device, and the indication information instructs the first network device to send a switching completion message to the second network device; the first network device sends the switching completion message to the second network device according to the indication information.

[0417] When the communication device 1100 is used to implement the functions of the terminal device in the method embodiment shown in FIG5 :

[0418] The processing unit 1110 calls the transceiver unit 1120 to execute: receiving first CSI configuration information and second CSI configuration information, the terminal device measuring the reference signal of the first network device according to the first CSI configuration information to obtain a first CSI report, and measuring the reference signal of the second network device according to the second CSI configuration information to obtain a second CSI report; the terminal device sends the first CSI report to the first network device; if the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, the terminal device sends indication information to the first network device, the indication information is used to instruct the first network device to send a switching completion message to the second network device, where N is a positive integer.

[0419] In one possible design, the transceiver unit 1120 is used to receive a switching command from the second network device, where the switching command indicates that the switching process of the terminal device is DAPS switching.

[0420] In one possible design, the first CSI report is carried via a random access message.

[0421] In one possible design, the N parameters include at least one of CQI, L1-RSRP, and L1-SINR.

[0422] When the communication device 1100 is used to implement the function of the first network device in the method embodiment shown in FIG6 :

[0423] The processing unit 1110 calls the transceiver unit 1120 to execute: receiving a switching request message from the second network device; the first network device sends third CSI configuration information and fourth CSI configuration information; wherein, the reporting period of the third CSI report configured by the third CSI configuration information is greater than the reporting period of the fourth CSI report configured by the fourth CSI configuration information; or, the reporting type of the fourth CSI report configured by the fourth CSI configuration information is dynamic reporting, and the reporting type of the third CSI report configured by the third CSI configuration information is periodic reporting; wherein, the third CSI report is obtained by the terminal device according to the reference signal measurement configured by the third CSI configuration information, and the fourth CSI report is obtained by the terminal device according to the reference signal measurement configured by the fourth CSI configuration information.

[0424] In one possible design, the transceiver unit 1120 is used to receive a second CSI report; the second CSI report is a CSI report measured by the terminal device based on the reference signal of the second network device, and receives the fourth CSI report; if the values ​​of N parameters in the fourth CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, a switching completion message is sent to the second network device, where N is a positive integer.

[0425] In one possible design, the transceiver unit 1120 is used to receive a second CSI report; the second CSI report is a CSI report measured by the terminal device based on the reference signal of the second network device; receive the third CSI report; if the values ​​of N parameters in the third CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, send a switching completion message to the second network device, where N is a positive integer.

[0426] In one possible design, the transceiver unit 1120 is used to receive a second CSI report; the second CSI report is a CSI report measured by the terminal device based on the reference signal of the second network device; receive the third CSI report and the fourth CSI report; if the values ​​of N parameters in at least one of the third CSI report and the fourth CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, a switching completion message is sent to the second network device, where N is a positive integer.

[0427] A more detailed description of the processing unit 1110 and the transceiver unit 1120 can be directly obtained by referring to the relevant description in the method embodiment shown in FIG2 , and is not repeated here.

[0428] As shown in Figure 12, communication device 1200 includes a processor 1210 and an interface circuit 1220. Processor 1210 and interface circuit 1220 are coupled to each other. It is understood that interface circuit 1220 may be a transceiver or an input / output interface. Optionally, communication device 1200 may further include a memory 1230 for storing instructions executed by processor 1210, input data required by processor 1210 to execute instructions, or data generated by processor 1210 after executing instructions.

[0429] When the communication device 1200 is used to implement the method shown in FIG. 2 , the processor 1210 is used to implement the functions of the processing unit 1110 , and the interface circuit 1220 is used to implement the functions of the transceiver unit 1120 .

[0430] When the communication device is a chip used in a terminal device, the terminal device chip implements the functions of the terminal device in the above method embodiments. The terminal device chip receives information from other modules in the terminal device (such as a radio frequency module or antenna), and the information is sent by the network device to the terminal device; or the terminal device chip sends information to other modules in the terminal device (such as a radio frequency module or antenna), and the information is sent by the terminal device to the network device.

[0431] When the above-mentioned communication device is a module applied to a network device, the network device module implements the functions of the network device in the above-mentioned method embodiment. The network device module receives information from other modules in the network device (such as a radio frequency module or an antenna), and the information is sent by the terminal device to the network device; or the network device module sends information to other modules in the network device (such as a radio frequency module or an antenna), and the information is sent by the network device to the terminal device. The network device module here can be a baseband chip of the network device, or it can be a DU or other module. The DU here can be a DU under the open radio access network (O-RAN) architecture.

[0432] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0433] The present application provides another example of a device, which includes at least one processor and at least one memory, the at least one processor and the at least one memory being coupled together, the at least one memory being used to store instructions. When the instructions are executed by the at least one processor, the communication device executes the method in the above-described embodiment. For example, as shown in FIG12 , a communication device 1200 includes a processor 1210 and a memory 1230. The processor 1210 and the memory 1230 are coupled together, and the memory 1230 stores instructions. When the instructions stored in the memory 1230 are executed by the processor 1210, the communication device 1200 executes the method executed by the network device or terminal device in the above-described embodiment.

[0434] The method steps in the embodiments of the present application can be implemented in hardware or in software instructions that can be executed by a processor. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disk, mobile hard disk, CD-ROM or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. The storage medium can also be an integral part of the processor. The processor and storage medium can be located in an ASIC. In addition, the ASIC can be located in a network device or a terminal device. The processor and storage medium can also be present in a network device or a terminal device as discrete components.

[0435] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video disk; or a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage media.

[0436] In the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0437] It is understood that the various numbers used in the embodiments of this application are merely for ease of description and are not intended to limit the scope of the embodiments of this application. The order of the sequence numbers of the above-mentioned processes does not necessarily imply a specific order of execution; the order of execution of the processes should be determined by their functions and inherent logic.

Claims

1. A communication method, characterized in that: The method includes: The first network device receives a switching request message from the second network device; The first network device obtains a first channel state information CSI report and a second CSI report, where the first CSI report is a CSI report measured by a terminal device based on a reference signal of the first network device, and the second CSI report is a CSI report measured by the terminal device based on a reference signal of the second network device; If the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of corresponding parameters in the second CSI report, the first network device sends a switching completion message to the second network device, where N is a positive integer.

2. The method according to claim 1, characterized in that The first network device obtains a second CSI report, including: The first network device receives the second CSI report from the second network device or from the terminal device.

3. The method according to claim 2, characterized in that The first network device receiving the second CSI report from the second network device includes: The first network device receives the handover request message from the second network device, where the handover request message includes the second CSI report.

4. The method according to claim 2, characterized in that The first network device receiving the second CSI report from the terminal device includes: The first network device receives a random access message from the terminal device, where the random access message includes the second CSI report.

5. The method according to any one of claims 1 to 4, characterized in that: The first network device obtains a first CSI report, including: The first network device receives a first CSI report from the terminal device.

6. The method according to claim 5, characterized in that The first CSI report is carried by a random access message.

7. The method according to any one of claims 1 to 6, characterized in that: The N parameters include at least one of a channel quality indicator CQI, a layer 1 reference signal received power L1-RSRP, and a layer 1 signal to interference plus noise ratio L1-SINR.

8. The method according to any one of claims 1 to 7, characterized in that: The first network device is a target network device; the second network device is a source network device.

9. A communication method, characterized in that: The method includes: The terminal device receives a radio resource control reconfiguration message from the second network device, wherein the radio resource control reconfiguration message indicates that the switching process of the terminal device is a dual activation protocol stack DAPS switching; The terminal device sends a second CSI report to the first network device; the second CSI report is a CSI report measured by the terminal device based on a reference signal of the second network device.

10. The method according to claim 9, characterized in that The second CSI report is carried by a random access message.

11. The method according to claim 9 or 10, characterized in that The first network device is a target network device; the second network device is a source network device.

12. A communication method, characterized in that: The method includes: The second network device sends a switching request message to the first network device; The second network device sends a second CSI report to the first network device; the second CSI report is a CSI report measured by the terminal device based on the reference signal of the second network device; The terminal device sends a first CSI report to the first network device; the first CSI report is a CSI report measured by the terminal device based on a reference signal of the first network device; The first network device receives the first CSI report and the second CSI report. If the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of corresponding parameters in the second CSI report, the first network device sends a switching completion message to the second network device, where N is a positive integer.

13. A communication method, characterized in that: The method includes: The second network device sends a handover request message to the first network device; the handover request message includes a second CSI report; the second CSI report is a CSI report measured by the terminal device based on the reference signal of the second network device; The terminal device sends a first CSI report to the first network device; the first CSI report is a CSI report measured by the terminal device based on a reference signal of the first network device; The first network device receives the first CSI report and the second CSI report. If the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of corresponding parameters in the second CSI report, the first network device sends a switching completion message to the second network device, where N is a positive integer.

14. A communication method, characterized in that: The method includes: The second network device sends a switching request message to the first network device; The second network device sends a radio resource control reconfiguration message to the terminal device, where the radio resource control reconfiguration message indicates that the switching process of the terminal device is a DAPS switching; The terminal device sends a first CSI report and a second CSI report to the first network device; the first CSI report is a CSI report measured by the terminal device based on a reference signal of the first network device; the second CSI report is a CSI report measured by the terminal device based on a reference signal of the second network device; The first network device receives the first CSI report and the second CSI report. If the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of corresponding parameters in the second CSI report, the first network device sends a switching completion message to the second network device, where N is a positive integer.

15. A communication method, characterized in that: The method includes: The terminal device receives the first CSI configuration information and the second CSI configuration information, the terminal device measures the reference signal of the first network device according to the first CSI configuration information to obtain a first CSI report, and measures the reference signal of the second network device according to the second CSI configuration information to obtain a second CSI report; If the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of the corresponding parameters in the second CSI report, the terminal device sends an indication message to the first network device, where the indication information is used to instruct the first network device to send a switching completion message to the second network device, and N is a positive integer.

16. The method according to claim 15, characterized in that Also includes: The terminal device receives a radio resource control reconfiguration message from the second network device, and the radio resource control reconfiguration message indicates that the switching process of the terminal device is DAPS switching.

17. The method according to claim 15 or 16, characterized in that The first CSI report is carried by a random access message.

18. The method according to any one of claims 15 to 17, characterized in that: The N parameters include at least one of CQI, L1-RSRP, and L1-SINR.

19. The method according to any one of claims 15 to 18, characterized in that: The first network device is a target network device; the second network device is a source network device.

20. A communication method, characterized in that: The method includes: The first network device receives a switching request message from the second network device; The first network device receives instruction information from a terminal device, where the instruction information instructs the first network device to send a switching completion message to the second network device; The first network device sends the switching completion message to the second network device according to the indication information.

21. The method of claim 20, wherein: The first network device is a target network device; the second network device is a source network device.

22. A communication method, characterized in that: The method includes: The second network device sends second CSI configuration information to the terminal device; The second network device sends a switching request message to the first network device; The first network device or the second network device sends first CSI configuration information to the terminal device; The terminal device receives the first CSI configuration information and the second CSI configuration information, the terminal device measures a reference signal of a first network device according to the first CSI configuration information to obtain a first CSI report, and measures a reference signal of a second network device according to the second CSI configuration information to obtain a second CSI report; If the values ​​of N parameters in the first CSI report are greater than or equal to the values ​​of corresponding parameters in the second CSI report, the terminal device sends indication information to the first network device, where the indication information is used to instruct the first network device to send a handover completion message to the second network device, and N is a positive integer; The first network device receives indication information from the terminal device, and the first network device sends the switching completion message to the second network device according to the indication information.

23. A communication method, characterized in that: The method includes: The first network device receives a switching request message from the second network device; The first network device sends third CSI configuration information and fourth CSI configuration information; The reporting period of the third CSI report configured by the third CSI configuration information is greater than the reporting period of the fourth CSI report configured by the fourth CSI configuration information; or, the reporting type of the fourth CSI report configured by the fourth CSI configuration information is dynamic reporting, and the reporting type of the third CSI report configured by the third CSI configuration information is periodic reporting, wherein the third CSI report is obtained by the terminal device according to the reference signal measurement configured by the third CSI configuration information, and the fourth CSI report is obtained by the terminal device according to the reference signal measurement configured by the fourth CSI configuration information.

24. The method of claim 23, wherein: Also includes: The first network device receives a second CSI report; the second CSI report is a CSI report measured by the terminal device based on a reference signal of the second network device; The first network device receives the fourth CSI report; If the values ​​of N parameters in the fourth CSI report are greater than or equal to the values ​​of corresponding parameters in the second CSI report, the first network device sends a switching completion message to the second network device, where N is a positive integer.

25. The method of claim 23, wherein: Also includes: The first network device receives a second CSI report; the second CSI report is a CSI report measured by the terminal device based on a reference signal of the second network device; The first network device receives the third CSI report; If the values ​​of N parameters in the third CSI report are greater than or equal to the values ​​of corresponding parameters in the second CSI report, the first network device sends a switching completion message to the second network device, where N is a positive integer.

26. The method of claim 23, wherein: Also includes: The first network device receives a second CSI report; the second CSI report is a CSI report measured by the terminal device based on a reference signal of the second network device; The first network device receives the third CSI report and the fourth CSI report; There are N parameter values ​​in at least one of the third CSI report and the fourth CSI report that are greater than or equal to the values ​​of corresponding parameters in the second CSI report, and the first network device sends a switching completion message to the second network device, where N is a positive integer.

27. A communication method, characterized in that: The method includes: The second network device sends a switching request message to the first network device; The first network device sends third CSI configuration information and fourth CSI configuration information; wherein a reporting period of a third CSI report configured by the third CSI configuration information is greater than a reporting period of a fourth CSI report configured by the fourth CSI configuration information; or, a reporting type of a fourth CSI report configured by the fourth CSI configuration information is dynamic reporting, and a reporting type of a third CSI report configured by the third CSI configuration information is periodic reporting; The terminal device receives the third CSI configuration information and the fourth CSI configuration information, the terminal device measures the reference signal configured by the third CSI configuration information according to the third CSI configuration information to obtain the third CSI report, and measures the reference signal configured by the fourth CSI configuration information according to the fourth CSI configuration information to obtain the fourth CSI report; The terminal device sends the third CSI report and the fourth CSI report to the first network device.

28. A communication device, characterized in that: The method comprises a unit or module for executing the method as claimed in any one of claims 1 to 8, or comprises a unit or module for executing the method as claimed in any one of claims 9 to 11, or comprises a unit or module for executing the method as claimed in any one of claims 15 to 19, or comprises a unit or module for executing the method as claimed in any one of claims 20 to 21, or comprises a unit or module for executing the method as claimed in any one of claims 23 to 26.

29. A communication device, characterized in that: include: One or more processors, wherein the one or more processors are configured to execute the method as described in any one of claims 1-8, or to execute the method as described in any one of claims 9-11, or to execute the method as described in any one of claims 15-19, or to execute the method as described in any one of claims 20-21, or to execute the method as described in any one of claims 23-26.

30. A chip system, characterized in that: The chip system includes at least one chip and a memory, and the at least one chip is used to read and execute the program stored in the memory to implement the method as described in any one of claims 1 to 8, or the method as described in any one of claims 9 to 11, or the method as described in any one of claims 15 to 19, or the method as described in any one of claims 20 to 21, or the method as described in any one of claims 23 to 26.

31. A readable storage medium, characterized in that: The readable storage medium includes a program, which, when executed on a device, enables the device to execute the method as described in any one of claims 1 to 8, or the method as described in any one of claims 9 to 11, or the method as described in any one of claims 15 to 19, or the method as described in any one of claims 20 to 21, or the method as described in any one of claims 23 to 26.

32. A computer program product, characterized in that Contains instructions, which, when executed on a computer, cause the computer to execute the method as claimed in any one of claims 1 to 8, or the method as claimed in any one of claims 9 to 11, or the method as claimed in any one of claims 15 to 19, or the method as claimed in any one of claims 20 to 21, or the method as claimed in any one of claims 23 to 26.

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