WO2021087832A1

WO2021087832A1 - Wireless communication method and terminal device

Info

Publication number: WO2021087832A1
Application number: PCT/CN2019/116100
Authority: WO
Inventors: 尤心
Original assignee: Oppo广东移动通信有限公司
Priority date: 2019-11-06
Filing date: 2019-11-06
Publication date: 2021-05-14
Also published as: CN114342465A

Abstract

Provided are a wireless communication method and a terminal device. The method is applied to the terminal device, and comprises: in the process of handover, from a source network device to a target network device on the basis of a dual active protocol stack (DAPS), of data transmission, if a handover command is received, performing handover, from a source cell to a target cell, of Uplink Packet Data Convergence Protocol (UL PDCP) Protocol Data Unit (PDU) transmission. By means of the handover command, the terminal device is triggered to perform handover of the UL PDCP PDU transmission from the source cell to the target cell. For a scenario in which a random access is not required, it can be ensured that the terminal device only transfers data to the target cell after correctly accessing to the target cell, so as to reduce the probability of handover failure or ping-pong handover back to the source cell due to incorrect access to target cell communication, thereby improving the user experience.

Description

Wireless communication method and terminal equipment

Technical field

The embodiments of the present application relate to the field of communication, and more specifically, to a method and terminal device for wireless communication.

Background technique

In the 3rd Generation Partnership Project (The 3rd Generation Partnership Project, 3GPP) mobility enhancement topics (including Long Term Evolution (LTE) and New Radio (NR)), it is proposed that the terminal equipment is The optimization method to reduce the interruption time during handover includes the following two architectures.

The first architecture is Dual Connection based Handover (DC based HO). Specifically, during cell handover, the terminal device first adds the target base station as a secondary node (Secondary Node, SN), and then performs role conversion The (role change) signaling changes the target base station into a master node (Master Node, MN), and finally releases the source base station, so as to achieve the effect of reducing the interruption time during handover.

The second architecture is based on the enhanced mobile ultra-broadband (Enhance Mobile Broadband, eMBB based Handover, eMBB based HO), also known as the eMBB handover process based on the dual active protocol stack (DAPS) implementation. Specifically, when the terminal device receives the HO command, it continues to maintain the connection with the source base station and initiates random access to the target base station, and the connection of the source base station is not released until the terminal device completes the access to the target base station.

However, in the DAPS-based handover process (such as the RACH-based DAPS handover process), the terminal device can only transfer the uplink packet data aggregation protocol (Uplink Packet Data) when the random access channel (Random Access Channel, RACH) process is successful. Convergence Protocol, UL PDCP) transfer to the target cell. In the LTE system, the second architecture is not applicable to specific scenarios. For example, the target cell can determine that the timing advance (TA) from the terminal device to the source cell is the same as the TA to the target cell, or the TA from the terminal device to the target cell is 0).

Therefore, how to ensure that the terminal device can correctly access the target cell before transferring the data to the target cell, so as to reduce the probability of handover failure or ping-pong handover back to the source cell due to incorrect communication of the target cell, thereby improving user experience .

Summary of the invention

Provides a wireless communication method and terminal equipment, aiming at scenarios that do not require random access, it can ensure that the terminal equipment correctly accesses the target cell before transferring data to the target cell, so as to reduce the incorrect access due to the communication of the target cell. The resulting handover failure or the probability of ping-pong handover back to the source cell, thereby improving user experience.

In the first aspect, a wireless communication method is provided, which is applied to a terminal device, and includes:

In the process of switching data transmission from the source network device to the target network device based on the dual activity protocol stack DAPS, if a switching command is received, the uplink packet data convergence protocol protocol data unit UL PDCP PDU transmission is switched from the source cell to the target cell.

In a second aspect, a terminal device is provided, which is used to execute the method in the first aspect or its implementation manners. Specifically, the terminal device includes a functional module for executing the method in the foregoing first aspect or each of its implementation manners.

In a third aspect, a terminal device is provided, including a processor and a memory. The memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute the method in the foregoing first aspect or each of its implementation manners.

In a fourth aspect, a chip is provided, which is used to implement the method in the first aspect or its implementation manners. Specifically, the chip includes: a processor, configured to call and run a computer program from a memory, so that a device installed with the chip executes the method in the above-mentioned first aspect or each of its implementation manners.

In a fifth aspect, a computer-readable storage medium is provided for storing a computer program that enables a computer to execute the method in the above-mentioned first aspect or each of its implementation manners.

In a sixth aspect, a computer program product is provided, including computer program instructions that cause a computer to execute the method in the first aspect or its implementation manners.

In a seventh aspect, a computer program is provided, which when running on a computer, causes the computer to execute the method in the first aspect or its implementation manners.

Based on the above technical solution, the handover command triggers the terminal device to switch UL PDCP PDU transmission from the source cell to the target cell in the process of handover from the source network device to the target network device based on DAPS. It can ensure that the terminal device correctly connects to the target cell before transferring data to the target cell, so as to reduce the probability of handover failure or ping-pong handover back to the source cell due to incorrect communication of the target cell, thereby improving user experience .

Description of the drawings

Figure 1 is an example of the application scenario of this application.

Fig. 2 is a schematic flowchart of a 4-step random access process in an embodiment of the present application.

Fig. 3 is a schematic block diagram of a MAC PDU according to an embodiment of the present application.

FIG. 4 is a schematic block diagram of a MAC RAR according to an embodiment of the present application.

Fig. 5 is a schematic flowchart of a 2-step random access process in an embodiment of the present application.

Fig. 6 is a schematic flowchart of a cell handover process provided by an embodiment of the present application.

FIG. 7 is a schematic flowchart of a wireless communication method according to an embodiment of the present application.

Figures 8 and 9 are schematic block diagrams of terminal devices according to embodiments of the present application.

FIG. 10 is a schematic block diagram of a chip of an embodiment of the present application.

Detailed ways

The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

Fig. 1 is a schematic diagram of an application scenario of an embodiment of the present application.

As shown in FIG. 1, the communication system 100 may include a terminal device 110 and a network device 120. The network device 120 may communicate with the terminal device 110 through an air interface. The terminal device 110 and the network device 120 support multi-service transmission.

It should be understood that the embodiment of the present application only uses the communication system 100 for exemplary description, but the embodiment of the present application is not limited thereto. That is to say, the technical solutions of the embodiments of the present application can be applied to various communication systems, such as: Long Term Evolution (LTE) system, LTE Time Division Duplex (TDD), Universal Mobile Communication System (Universal Mobile Telecommunication System, UMTS), 5G communication system (also known as New Radio (NR) communication system), or future communication system, etc.

In the communication system 100 shown in FIG. 1, the network device 120 may be an access network device that communicates with the terminal device 110. The access network device can provide communication coverage for a specific geographic area, and can communicate with the terminal device 110 (for example, UE) located in the coverage area.

The network equipment 120 may be an evolved base station (Evolutional Node B, eNB or eNodeB) in a Long Term Evolution (LTE) system, or a Next Generation Radio Access Network (NG RAN) equipment, Either the base station (gNB) in the NR system, or the wireless controller in the Cloud Radio Access Network (CRAN), or the network device 120 can be a relay station, an access point, a vehicle-mounted device, or a wearable Equipment, hubs, switches, bridges, routers, or network equipment in the future evolution of the Public Land Mobile Network (PLMN).

The terminal device 110 may be any terminal device, which includes, but is not limited to, a terminal device connected to the network device 120 or other terminal devices in a wired or wireless connection.

For example, the terminal device 110 may refer to an access terminal, user equipment (User Equipment, UE), user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile equipment, user terminal, terminal, wireless communication Equipment, user agent, or user device. The access terminal can be a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a wireless local loop (Wireless Local Loop, WLL) station, a personal digital processing (Personal Digital Assistant, PDA), with wireless communication Functional handheld devices, computing devices or other processing devices connected to wireless modems, in-vehicle devices, wearable devices, terminal devices in 5G networks, or terminal devices in future evolution networks, etc.

The terminal device 110 may be used for device-to-device (D2D) communication.

The wireless communication system 100 may also include a core network device 130 that communicates with a base station. The core network device 130 may be a 5G core network (5G Core, 5GC) device, for example, an access and mobility management function (Access and Mobility Management Function). , AMF), for example, authentication server function (Authentication Server Function, AUSF), for example, user plane function (User Plane Function, UPF), for example, session management function (Session Management Function, SMF). Optionally, the core network device 130 may also be an Evolved Packet Core (EPC) device of the LTE network, for example, a session management function + a data gateway (Session Management Function+Core Packet Gateway, SMF+PGW-) of the LTE network. C) Equipment. It should be understood that SMF+PGW-C can simultaneously realize the functions that SMF and PGW-C can realize. In the process of network evolution, the aforementioned core network equipment may also be called by other names, or a new network entity may be formed by dividing the functions of the core network, which is not limited in the embodiment of the present application.

Each functional unit in the communication system 100 may also establish a connection through a next generation network (NG) interface to achieve communication.

For example, the terminal device establishes an air interface connection with the access network device through the NR interface for transmitting user plane data and control plane signaling; the terminal device can establish a control plane signaling connection with the AMF through the NG interface 1 (abbreviated as N1); access Network equipment, such as the next generation wireless access base station (gNB), can establish a user plane data connection with UPF through NG interface 3 (abbreviated as N3); access network equipment can establish control plane signaling with AMF through NG interface 2 (abbreviated as N2) Connection; UPF can establish control plane signaling connection with SMF through NG interface 4 (abbreviated as N4); UPF can exchange user plane data with the data network via NG interface 6 (abbreviated as N6); AMF can communicate with SMF via NG interface 11 (abbreviated as N11) SMF establishes control plane signaling connection; SMF can establish control plane signaling connection with PCF through NG interface 7 (abbreviated as N7).

Figure 1 exemplarily shows a base station, a core network device and two terminal devices. Optionally, the wireless communication system 100 may include multiple base station devices and the coverage of each base station may include other numbers of terminals. Equipment, this embodiment of the application does not limit this.

It should be understood that all devices with communication functions in the network/system in the embodiments of the present application can be referred to as communication devices. Taking the communication system 100 shown in FIG. 1 as an example, the communication device may include a network device 120 and a terminal device 110 having communication functions, and the network device 120 and the terminal device 110 may be the above-mentioned devices, which will not be repeated here; The communication device may also include other devices in the communication system 100, such as other network entities such as a network controller and a mobility management entity, which are not limited in the embodiment of the present application.

It should be understood that the terms "system" and "network" in this article are often used interchangeably in this article. The term "and/or" in this article is only an association relationship describing the associated objects, which means that there can be three relationships, for example, A and/or B, which can mean: A alone exists, A and B exist at the same time, exist alone B these three situations. In addition, the character "/" in this text generally indicates that the associated objects before and after are in an "or" relationship.

In some embodiments of the present application, the communication system may be an NR system.

In other words, the communication system 100 can be used to perform a 4-step random access procedure.

For example, after the cell search process, the terminal device has achieved downlink synchronization with the cell, so the terminal device can receive downlink data. However, the terminal equipment can only perform uplink transmission if it has achieved uplink synchronization with the cell. The terminal device establishes a connection with the cell and obtains uplink synchronization through a random access procedure (Random Access Procedure).

The main purpose of random access is: (1) Obtain uplink synchronization; (2) Assign a unique identification C-RNTI to the terminal equipment.

The random access process can be triggered by one of the following 6 types of events:

1. Establish a wireless connection during initial access: the terminal device will go from the RRC_IDLE state to the RRC_CONNECTED state.

2. The RRC Connection Re-establishment procedure: so that the terminal device can reestablish the wireless connection after the radio link failure (Radio Link Failure).

3. Handover: At this time, the terminal device needs to establish uplink synchronization with the new cell.

4. In the RRC_CONNECTED state, when the downlink data arrives (the ACK/NACK needs to be returned at this time), the uplink is in the "unsynchronized" state.

5. In the RRC_CONNECTED state, when the uplink data arrives (for example, it is necessary to report a measurement report or send user data), the uplink is in the "out of synchronization" state or there is no available PUCCH resource for SR transmission (at this time, the uplink synchronization state is allowed The terminal equipment uses RACH to replace the role of SR).

6. In the RRC_CONNECTED state, in order to locate the terminal device, timing advance is required.

As shown in FIG. 2, the 4-step random access process 200 may include:

S210: The terminal device sends a random access preamble sequence (message 1, MSG1) to the network device.

S220: After detecting that a terminal device sends an access preamble sequence, the network device sends a random access response (RAR, that is, message 2, MSG2) to the terminal device to inform the terminal device of the uplink that can be used for sending MSG3 (message 3, MSG3). Resource information, assign temporary RNTI to the terminal device, provide TA command to the terminal device, etc. If the terminal device does not detect the RAR in the RAR window, the terminal device retransmits the PRACH sequence. If the terminal device detects the RAR in the RAR window, The terminal equipment transmits MSG3 according to the UL grant indicated by the RAR.

S230: After receiving the random access response RAR, the terminal device sends an MSG3 message in the uplink resource specified by the random access response message, and this step allows HARQ retransmission;

S240: The network device sends an MSG4 message to the terminal device, including a contention resolution message, and at the same time allocates uplink transmission resources for the terminal device. This step allows HARQ retransmission. When the terminal device receives the MSG4 sent by the network device, it will detect whether the MSG4 includes part of the content in the MSG3 message sent by the terminal device. If it is included, it indicates that the random access process of the terminal device is successful, otherwise it is considered that the random process has failed, and the terminal device needs to initiate the random access process again from the first step.

In the process 200, the RAR sent by the network device to the terminal device is a response to Msg1, and the RA-RNTI used when the network device sends the RAR is calculated based on the location of the PRACH time-frequency resource, and one RA-RNTI scrambling code The PDSCH corresponding to the PDCCH may include responses to multiple preamble sequences.

For example, the terminal equipment does not detect RAR includes the following situations:

1. No RA-RNTI scrambling PDCCH is detected.

2. The RA-RNTI scrambled PDCCH is detected but the corresponding PDSCH is not received correctly.

3. The PDSCH is received but the RAR message corresponding to the MSG1 is not included in the PDSCH.

The detection of RAR by the terminal device may refer to the RA-RNTI calculated by the terminal device in the RAR window according to the time-frequency resource position of sending MSG1, and the PDSCH scheduled by the PDCCH of the RA-RNTI scrambling code is correctly received, and the PDSCH includes the MSG1 The corresponding RAR message.

The terminal device detects the PDCCH of the RA-RNTI scrambling code, and detects the PDSCH scheduled by the PDCCH; the PDSCH includes at least one RAR message, one of which is a response to the preamble sequence sent by the terminal device; in each RAR message Including preamble sequence ID, TA, UL grant, TC-RNTI and other information; UL grant includes the following scheduling information: frequency domain hopping flag, frequency domain resource allocation, time domain resource allocation, MCS, TPC, CSI request and other information.

If the RAR is detected in the RAR window, the terminal device transmits Msg3 according to the UL grant included in the RAR message. The length of the RAR time window is represented by the number of time slots, and the length can be configured by high-level signaling ra-ResponseWindow, and the time slot length is determined based on the subcarrier interval of the Type1-PDCCH common search space set for the reference subcarrier. The RAR time window starts in the Type1-PDCCH CSS set configured for the terminal, and the terminal at least one symbol after the last symbol of the PRACH occasion where the PRACH is sent by the terminal receives the CORESET with the earliest PDCCH time position, and the at least one The symbol length of the symbol corresponds to the subcarrier spacing of Type1-PDCCH CSS set.

As shown in Figure 3, the Media Access Control (MAC) protocol data unit (Protocol Data Unit, PDU) can include multiple MAC sub-PDUs (Media Access Control subPDU, MAC subPDU) and possible padding (padding) ) Bits.

For example, MAC subPDU 1 may belong to the E/T/R/R/BI subheader. The MAC subPDU following the E/T/R/R/BI subheader may belong to the E/T/RAPID subheader. The MAC subPDU in the E/T/R/R/BI subheader may include only RAPID, or may include both RAPID and the corresponding MAC random access response (Random Access Response, RAR). For example, MAC subPDU 2 only includes RAPID, and MAC subPDU 3 includes both RAPID and the corresponding RAR.

In other words, one MAC PDU can include one or more MAC RARs.

It can be seen from the structure of MAC PDU that if a network device detects random access requests from multiple terminal devices on the same PRACH resource, it can use one MAC PDU to respond to these access requests. Each random access The response to the request (corresponding to a preamble index) corresponds to a RAR. In other words, if multiple terminal devices send the preamble on the same PRACH resource (the same time and frequency position, using the same RA-RNTI), the corresponding RARs are multiplexed in the same MAC PDU.

The MAC PDU is transmitted on the DL-SCH and is scheduled through the PDCCH scrambled with RA-RNTI.

In other words, all terminal devices that use the same PRACH resource to send preambles (not necessarily the same) listen to the same RA-RNTI scrambled PDCCH and receive the same MAC PDU, but terminal devices that use different preamble indexes can be based on the corresponding RAPID value Find the corresponding RAR.

The fallback instruction (BI) subheader may include an extension field (extension, E), a type field (type, T), two reserved fields (reserved, R), and a BI value.

The random access sequence identifier (Random Access Preamble Identifier, RAPID) subheader may include an E, a T, and a RAPID value.

Among them, the random access sequence identifier (Random Access Preamble Identifier, RAPID) is the preamble index obtained when the network device detects the preamble. If the terminal device finds that the value is the same as the index used when sending the preamble, it is considered that the corresponding RAR has been successfully received.

As shown in Figure 4, MAC RAR may include reserved bits R, time alignment command (Timing alignment Command, TAC), uplink grant (UL grant), and temporary Cell Radio Network Temporary Identifier (TC) -RNTI).

Among them, the time alignment command (Timing Alignment Command, TAC) is used to specify the amount of time adjustment required for the uplink synchronization of the terminal device, which can occupy 12 bits. UL grant specifies the uplink resources allocated to Msg3. When there is uplink data transmission, for example, conflicts need to be resolved, the grant allocated by the network device in the RAR cannot be less than 56 bits. TC-RNTI is used for subsequent transmission of terminal equipment and network equipment. After the conflict is resolved, the value may become C-RNIT.

During the transmission of MSG3 in the four-step RACH process, the RV version number used for the MSG3 transmission scheduled by UL grant in RAR is 0. If the network device fails to receive MSG3, the network device will use the DCI format of the TC-RNTI scrambling code 0_0 To schedule the retransmission of MSG3.

The DCI format 0_0 of the TC-RNTI scrambling code can include the following:

Uplink and downlink DCI indication (1 bit), frequency domain resource allocation (the size is determined by UL BWP bandwidth), time domain resource allocation (4 bits), frequency domain frequency hopping indication (1 bit), MCS (5 bits), new data indication (1 bit reserved), RV version (2 bits), HARQ process number (4 bits reserved), PUSCH power control command word (2 bits), and UL/SUL carrier indication (1 bit).

During the transmission of MSG4 in the four-step RACH process, the terminal device performs PUCCH feedback after receiving Msg4. If the decoding result of MSG4 received by the terminal device is NACK, the network device will perform HARQ retransmission on Msg4. The network equipment will use the DCI format 1_0 of the C-RNTI or TC-RNTI scrambling code to schedule the initial transmission or retransmission of MSG4. If the terminal device receives the DCI format 1_0 of the C-RNTI scrambling code and its corresponding PDSCH, random access is completed; if the terminal device receives the DCI format 1_0 of the TC-RNTI scrambling code and its corresponding PDSCH, and the content is successfully compared , Random access is complete.

The DCI format 1_0 of the TC-RNTI scrambling code can include the following:

Uplink and downlink DCI indication (1 bit), frequency domain resource allocation (the size is determined by the DL BWP bandwidth), time domain resource allocation (4 bits), VRB to PRB mapping (1 bit), MCS (5 bits), new data indication ( 1 bit), RV version (2 bits), HARQ process number (4 bits), downlink allocation indicator DAI (2 bits reserved), PUCCH power control command word (2 bits), PUCCH resource indicator (3 bits), PDSCH- to-HARQ feedback time indication (3 bits).

In the four-step RACH process, due to the relatively large delay, it is not suitable for the low-latency and high-reliability scenarios in 5G. Taking into account the characteristics of low-latency and high-reliability related services, the communication system may use a two-step RACH process solution to reduce access delay.

FIG. 5 is a schematic flowchart of a two-step RACH process 300 according to an embodiment of the present application.

As shown in FIG. 5, the two-step RACH process 300 may include:

S310: The terminal device sends msgA to the network device. The msgA may include msg1 and msg3 of the 4-step RACH. .

S320: The terminal device receives the msgB sent by the network device, and the msgB may include msg2 and msg4 of the 4-step RACH.

In other words, combine the first and third steps in the 4-step RACH process into the first step in the 2-step RACH process (message A), and combine the second and fourth steps in the 4-step RACH process into 2 -step The second step in the RACH process (message B).

Therefore, in the first step in the 2-step RACH process, the terminal device needs to send the preamble and PUSCH.

For example, for msgA, it may include a preamble and an uplink data part (for example, carried by PUSCH), where the uplink data part carries the identification information of the terminal device and/or the reason for the RRC request (that is, equivalent to the content of the existing MSG3); The msgB can contain conflict resolution information, TA information, C-RNTI allocation information, etc., that is, a combination of information equivalent to the existing MSG2 and MSG4 information.

In the 2-step RACH process, when the terminal has random access requirements, the terminal sends the MsgA resource corresponding to the 2-step RACH process that occurs periodically in the network configuration, that is, RACH Occasion and PUSCH Occasion. Then, the terminal monitors the RAR message (msgB) sent by the network in the RAR response window.

The method for setting the starting time position of the RAR response window is similar to that in 4-step RACH, starting from the CSS set configured for the terminal (for example, it can be Type1-PDCCH CSS set), and the terminal sends msgA The terminal at least M symbols after the last symbol (for PUSCH occasion) receives the CORESET with the earliest PDCCH time position, and the symbol length of the at least M symbols corresponds to the subcarrier interval of Type1-PDCCH CSS set, where M is greater than An integer of 0.

The msgB RAR response message in the 2-step RACH process may also carry multiple msgA response messages sent by multiple terminal devices.

For example, it can be divided into the following types of messages:

Success RAR (SuccessRAR): If the network device successfully receives the preamble and PUSCH information in msgA, the terminal will feed back SuccessRAR, which can carry TA command, C-RNTI, conflict resolution ID, etc.;

Fallback RAR (FallbackRAR): If the network device successfully detects the preamble part of the terminal msgA, but does not receive the correct PUSCH part, the network can send FallbackRAR to the terminal so that the terminal can fall back to the traditional 4-step RACH process. After receiving FallbackRAR, the terminal sends msg3 to the network.

Of course, the msgB RAR response message can also carry other information, such as a Backoff indicator, which is used to indicate how to adjust the time parameters for retransmitting msgA when the terminal does not receive the RAR response message.

The network equipment provides services for the cell, and the terminal equipment communicates with the network equipment through the transmission resources (for example, frequency domain resources, or spectrum resources) used by the cell. The cell may be a cell corresponding to the network equipment (for example, a base station). It can belong to a macro base station or a base station corresponding to a small cell. The small cell here can include: Metro cell, Micro cell, Pico cell, Femto cell ( Femto cell), etc. These small cells have the characteristics of small coverage and low transmit power, and are suitable for providing high-rate data transmission services.

Similar to the LTE system, the NR system supports the handover process of connected terminal equipment. When a user who is using network services moves from one cell to another, or due to wireless transmission traffic load adjustment, activation operation and maintenance, equipment failure, etc., in order to ensure the continuity of communication and the quality of service, the system must transfer the user to The communication link with the source cell is transferred to the new cell, that is, the handover process is performed.

As shown in Figure 6, the Xn interface switching process is divided into the following three stages:

The first stage, handover preparation (1~5).

In 1, the source base station triggers the terminal device to measure the neighboring cell, so that the terminal device can measure the neighboring cell and report the measurement result to the source base station.

In 2, the source base station evaluates the measurement results reported by the terminal equipment and decides whether to trigger a handover.

In 3, if the source base station decides to trigger a handover, it can send a handover request to the target base station.

In 4, after the target base station receives the handover request sent by the source base station, it can start admission according to the service information carried by the source base station and perform radio resource configuration.

In 5, the target base station sends a handover request confirmation message to the source base station, and returns the admission result and wireless resource configuration information in the target base station to the source base station. The source base station receives the handover request acknowledgment (ACK) information sent by the target base station, including the handover command sent to the UE, the assigned new cell radio network temporary identifier (C-RNTI), and the information selected at the target base station The algorithm identifier of the security algorithm may include a dedicated random access channel (Random Access Channel, RACH) preamble and some other possible parameters. At this point, the handover preparation phase is complete. After receiving the handover request acknowledgement (ACK) information, the source base station allocates downlink resources for the UE.

In the second stage, switch execution (6-8).

In 6, after the source base station receives the handover request confirmation message of the target base station, it can trigger the terminal device to switch.

In 7, the source base station can forward the buffered data, the data packet in transit, the system serial number of the data, etc. to the target base station. And, the target base station can buffer the data received from the source base station

In addition, the terminal device can disconnect from the source base station and establish synchronization with the target base station.

In 8, the terminal equipment synchronizes to the target base station. At this point, the switching execution phase is complete.

In the third stage, the handover is completed (209-212).

In 9, the target base station sends a path switching request to the mobility management function (Access and Mobility Management Function, AMF).

In 10, after the AMF receives the path switching request of the target base station, it performs path switching with the User Plane Function (UPF) to clear the path mark of the user plane of the source base station.

In 11, after the path switching is completed, the AMF can send a path switching confirmation message to the target base station.

In 12, the target base station sends a terminal device context release message to the source base station to notify the source base station that the handover is successful, and trigger the source base station terminal device context. At this point, the switch is complete.

The conditional handover process based on conditional handover can solve the problems of frequent handover and easy handover failure in high-speed mobile scenarios and high-frequency deployment scenarios. The basic principle is: the terminal device evaluates the target cell-related conditions according to the conditions of the network device configuration. When the condition is triggered, the handover to the target cell is executed according to the pre-configured handover command (that is, the random access process is triggered and the handover complete message is sent), to avoid too late or unable to send the measurement report and receive the handover command due to high-speed movement into the poor coverage area The problem.

However, in the DAPS-based handover process (such as the RACH-based DAPS handover process), the terminal device can only transfer the uplink packet data aggregation protocol (Uplink Packet Data) when the random access channel (Random Access Channel, RACH) process is successful. Convergence Protocol, UL PDCP) transfer to the target cell. For example, after the message 2 or the message 4 is successfully received, the UL PDCP protocol data unit (Protocol Data Unit, PDU) can be transferred to the target cell. In the LTE system, the second architecture is not applicable to specific scenarios. For example, the target cell can determine that the timing advance (TA) from the terminal device to the source cell is the same as the TA to the target cell, or the TA from the terminal device to the target cell is 0).

FIG. 6 is a schematic flowchart of a wireless communication method 400 according to an embodiment of the present application. It should be understood that the method 400 may be executed by a terminal device. For example, the terminal device shown in Figure 1.

As shown in FIG. 6, the method 400 may include:

S410: In the process of switching from the source network device to the target network device based on the dual activity protocol stack DAPS, if a switching command is received, switch the uplink packet data convergence protocol protocol data unit UL PDCP PDU transmission from the source cell to the target cell.

For example, in a scenario where the target cell can determine that the timing advance (TA) of the terminal device to the source cell is the same as the TA to the target cell, or the TA from the terminal device to the target cell is 0), the terminal device receives After the switching command, it can be determined that the UL PDCP PDU transmission can be transferred without random access.

For scenarios that do not require random access, the handover command triggers the terminal device to switch UL PDCP PDU transmission from the source cell to the target cell during the process of switching from the source network device to the target network device based on DAPS, which can ensure The terminal device transfers data to the target cell only after correctly accessing the target cell, so as to reduce the probability of handover failure or ping-pong handover back to the source cell due to incorrect communication of the target cell, thereby improving user experience.

It should be noted that switching the UL PDCP PDU transmission from the source cell to the target cell by the terminal device can be understood as a conversion process including only data. For example, the terminal device converts the UL PDCP PDU generated using the compression algorithm and/or security algorithm and/or encryption algorithm corresponding to the source cell into the compression algorithm and/or security algorithm and/or encryption algorithm corresponding to the target cell to generate and send UL PDCP PDU for the target cell. Further, switching the UL PDCP PDU transmission from the source cell to the target cell by the terminal device can be understood as including the data conversion process and the data sending process. For example, the terminal device may first convert the UL PDCP PDU generated using the compression algorithm and/or security algorithm and/or encryption algorithm corresponding to the source cell into the compression algorithm and/or security algorithm and/or encryption algorithm corresponding to the target cell. Generate the UL PDCP PDU to be sent to the target cell, and then use the compression algorithm and/or security algorithm and/or encryption algorithm corresponding to the target cell to generate the UL PDCP PDU to be sent to the target cell and send it to the target cell.

In some embodiments of the present application, the S410 may include:

If the handover command includes information for instructing the terminal device to ignore the random access channel RACH-Less, switch the UL PDCP PDU transmission from the source cell to the target cell.

In other words, the target cell can be configured with RACH-skip information in the handover command, that is, the handover process can be RACH-less. In other words, through the information used to indicate the RACH-Less of the terminal device (such as the RACH-skip field), the terminal device can be directly or explicitly instructed to ignore the random access process, that is, the terminal device receives the RACH-skip in the handover information. After the field, the UL PDCP PDU transmission can be directly switched from the source cell to the target cell.

In some embodiments of the present application, the S410 may include:

If the handover command includes information for indicating pre-configured resources, the PDCP PDU transmission is handed over from the source cell to the target cell.

Optionally, the pre-configured resources include uplink resources.

For example, if the handover command includes information used to indicate RACH-Less and information used to indicate pre-configured resources, the terminal device may first use the compression algorithm and/or security algorithm and/or encryption algorithm corresponding to the source cell to generate UL PDCP PDU is converted into a UL PDCP PDU to be sent to the target cell using the compression algorithm and/or security algorithm and/or encryption algorithm corresponding to the target cell, and then the compression corresponding to the target cell can be used through the pre-configured resource Algorithms and/or security algorithms and/or encryption algorithms generate UL PDCP PDUs to be sent to the target cell and send them to the target cell.

Further, if the handover command includes information for indicating RACH-Less of the terminal device (for example, the RACH-skip field), and the handover command includes information for indicating pre-configured resources, the terminal device can use all The pre-configured resource switches the PDCP PDU transmission from the source cell to the target cell.

For example, the terminal device may use the first available resource among the pre-configured resources to switch the UL PDCP PDU transmission from the source cell to the target cell. Optionally, the first resource may be the first resource in the time domain, and/or the first resource may be the first resource in the frequency domain. Optionally, the first resource may include at least one resource symbol. For example, the first resource may be the first Orthogonal Frequency Division Multiplexing (OFDM) symbol. For another example, the first resource may be the first OFDM symbol and the first OFDM symbol.

Of course, the terminal device may also use available resources at other locations in the pre-configured resources to switch the UL PDCP PDU transmission from the source cell to the target cell. For example, the terminal device may use the last available resource in the pre-configured resources to switch the UL PDCP PDU transmission from the source cell to the target cell.

In some embodiments of the present application, the S410 may include:

If the handover command does not include information for indicating pre-configured resources, monitor the physical downlink control channel PDCCH scrambled with the C-RNTI of the cell radio network temporary identification; if the PDCCH scrambled with the C-RNTI is received, the PDCCH UL PDCP PDU transmission is switched from the source cell to the target cell.

Optionally, the PDCCH scrambled by using the C-RNTI may be a PDCCH sent by the target cell.

Optionally, the uplink resource (UL grant) is indicated in the PDCCH scrambled using the C-RNTI. That is, the PDCCH scrambled with the C-RNTI includes grant information for indicating uplink resources. The terminal device can use the uplink resource to switch the UL PDCP PDU transmission from the source cell to the target cell.

For example, if the handover command includes information for indicating RACH-Less and does not include information for indicating pre-configured resources, after the terminal device monitors the PDCCH scrambled with C-RNTI, the terminal device may first Convert the UL PDCP PDU generated by the compression algorithm and/or security algorithm and/or encryption algorithm corresponding to the source cell into the UL PDCP PDU generated by the compression algorithm and/or security algorithm and/or encryption algorithm corresponding to the target cell to be sent to the target cell PDCP PDU, then, through the uplink resources dynamically scheduled by the PDCCH, the compression algorithm and/or security algorithm and/or encryption algorithm corresponding to the target cell can be used to generate the UL PDCP PDU to be sent to the target cell and sent to the target cell .

Further, if the handover command includes information for indicating RACH-Less and does not include information for indicating pre-configured resources, the terminal device can use dynamic scheduling resources to switch the PDCP PDU transmission from the source cell to Target cell.

In some embodiments of the present application, the pre-configured resource is a shared resource of multiple terminal devices. At this time, in some embodiments of the present application, the S410 may include:

If a successful contention resolution message is received, the UL PDCP PDU transmission is switched from the source cell to the target cell.

For example, if the handover command includes information for indicating RACH-Less and information for indicating a pre-configured resource, assuming that the pre-configured resource is a shared resource of multiple terminal devices, the terminal device may successfully receive it. After the contention resolution message, the uplink PDCP PDU transmission is transferred to the target cell.

In some embodiments of the present application, the method 400 may further include:

On the pre-configured resource, a cell radio network temporary identifier C-RNTI and a radio resource control RRC reconfiguration complete message are sent.

In other words, when the preconfigured UL grant resource configured in the handover command is a shared resource of multiple terminal devices, the terminal device needs to transmit the C-RNTI and the RRC reconfiguration complete message (RRCReconfigurationComplete) on the UL grant. After the message, it waits to receive the contention resolution message, and only when the received contention resolution message is a successful contention resolution message can it be determined that the handover process is successful. At this time, the terminal device can transfer the uplink PDCP PDU transmission to the target cell.

It should be noted that the embodiment of the present application does not limit the specific content and form of the pre-configuration information. For example, the pre-configured resource is a periodic resource. For another example, the pre-configured resource is an uplink pre-configured resource. For another example, the information used to indicate the pre-configured resource is a periodic pre-configured uplink grant (preconfigured UL grant). For another example, the information used to indicate pre-configured resources includes at least one of the following information:

An identifier (numberOfConfUL-Processes) used to indicate the number of hybrid automatic repeat request (Hybrid Automatic Repeat Request, HARQ) processes corresponding to the pre-configured resource.

The scheduling interval of the pre-configured resource (ul-SchedInterval);

The start subframe number (ul-StartSubframe) of the pre-configured resource; and

Information (UL-Grant) used to indicate resources for transmitting the physical uplink shared channel PUSCH.

For example, numberOfConfUL-Processes can be 1, 2...8, ul-SchedInterval can be sf2, sf5, or sf10, ul-StartSubframe can be 0, 1...9, etc., and UL-Grant can be the maximum bit string (BIT STRING). For example, BIT STRING can be a value such as 16.

In some embodiments of the present application, the S410 may include:

If the handover command includes information for instructing the terminal equipment to adopt two-step random access, the UL PDCP PDU transmission is handed over from the source cell to the target cell.

For example, if message A is successfully sent or message B is successfully received, the terminal device can switch the UL PDCP PDU transmission from the source cell to the target cell.

In other words, after the two-step random access of the terminal device succeeds, the UL PDCP PDU transmission can be switched from the source cell to the target cell, and the two-step random access process is effectively compatible with the DAPS-based cell switching process.

The preferred embodiments of the present application are described in detail above with reference to the accompanying drawings. However, the present application is not limited to the specific details in the above-mentioned embodiments. Within the scope of the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application. These simple variants all belong to the protection scope of this application.

For example, the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described in this application. Explain separately.

For another example, various different implementations of this application can also be combined arbitrarily, as long as they do not violate the idea of this application, they should also be regarded as the content disclosed in this application.

It should be understood that in the various method embodiments of the present application, the size of the sequence number of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not be implemented in this application. The implementation process of the example constitutes any limitation.

The method embodiment of the present application is described in detail above, and the device embodiment of the present application is described in detail below with reference to FIG. 8 to FIG. 10.

FIG. 8 is a schematic block diagram of a terminal device 500 according to an embodiment of the present application.

Referring to FIG. 8, the terminal device 500 may include:

The transceiving unit 510 and the processing unit 520 are used to switch data transmission from the source network device to the target network device based on the dual activity protocol stack DAPS. If the transceiving unit 510 receives a switching command, the processing unit 520 is configured to The uplink packet data convergence protocol protocol data unit UL PDCP PDU transmission is handed over from the source cell to the target cell.

In some embodiments of the present application, the processing unit 520 is specifically configured to:

In some embodiments of the present application, the processing unit 520 is more specifically configured to:

If the handover command includes information for instructing the terminal device to ignore the random access channel RACH-Less and information for indicating pre-configured resources, the PDCP PDU transmission is switched from the source cell to the target cell.

Use the first available resource in the pre-configured resources to switch the UL PDCP PDU transmission from the source cell to the target cell.

In some embodiments of the present application, the transceiving unit 510 is further configured to:

If the handover command includes information for instructing the terminal device to ignore the random access channel RACH-Less and does not include information for instructing pre-configured resources, monitor the physical downlink control channel scrambled using the cell radio network temporary identifier C-RNTI PDCCH;

The processing unit 520 is more specifically configured to:

If the PDCCH scrambled with the C-RNTI is received, the UL PDCP PDU transmission is switched from the source cell to the target cell.

In some embodiments of the present application, the PDCCH scrambled using C-RNTI includes authorization information for indicating uplink resources.

In some embodiments of the present application, the pre-configured resource is a shared resource of multiple terminal devices.

In some embodiments of the present application, the pre-configured resource is a periodic resource.

In some embodiments of the present application, the information used to indicate pre-configured resources includes at least one of the following information:

An identifier used to indicate the number of HARQ processes corresponding to the pre-configured resource;

The scheduling interval of the pre-configured resource;

The starting subframe number of the pre-configured resource; and

Information used to indicate resources for transmitting the physical uplink shared channel PUSCH.

In some embodiments of the present application, the information used to indicate the pre-configured resource is the periodic pre-configured uplink grant.

If message A is successfully sent or message B is successfully received, the UL PDCP PDU transmission is switched from the source cell to the target cell.

It should be understood that the device embodiment and the method embodiment may correspond to each other, and similar descriptions may refer to the method embodiment. Specifically, the terminal device 500 shown in FIG. 8 may correspond to the corresponding main body in the method 400 that executes the embodiment of the present application, and the foregoing and other operations and/or functions of the various units in the terminal device 500 are respectively intended to realize For the sake of brevity, the corresponding procedures in each method of the method are not repeated here.

The communication device of the embodiment of the present application is described above from the perspective of functional modules in conjunction with the accompanying drawings. It should be understood that the functional module can be implemented in the form of hardware, can also be implemented in the form of software instructions, and can also be implemented in a combination of hardware and software modules.

Specifically, the steps of the method embodiments in the embodiments of the present application can be completed by hardware integrated logic circuits in the processor and/or instructions in the form of software. In combination with the steps of the methods disclosed in the embodiments of the present application, the steps can be directly embodied as hardware The execution of the decoding processor is completed, or the execution is completed by a combination of hardware and software modules in the decoding processor.

Optionally, the software module may be located in a mature storage medium in the field, such as a random access memory, a flash memory, a read only memory, a programmable read only memory, an electrically erasable programmable memory, and a register. The storage medium is located in the memory, and the processor reads the information in the memory, and completes the steps in the foregoing method embodiment in combination with its hardware.

For example, the processing unit and the communication unit referred to above may be implemented by a processor and a transceiver, respectively.

FIG. 9 is a schematic structural diagram of a terminal device 600 according to an embodiment of the present application.

Referring to FIG. 9, the terminal device 600 may include a processor 610.

The processor 610 may call and run a computer program from the memory to implement the method in the embodiment of the present application.

Please continue to refer to FIG. 9, the terminal device 600 may further include a memory 620.

Wherein, the memory 620 may be used to store instruction information, and may also be used to store codes and instructions executed by the processor 610. The processor 610 may call and run a computer program from the memory 620 to implement the method in the embodiment of the present application. The memory 620 may be a separate device independent of the processor 610, or may be integrated in the processor 610.

Please continue to refer to FIG. 9, the terminal device 600 may also include a transceiver 630.

The processor 610 may control the transceiver 630 to communicate with other devices, specifically, may send information or data to other devices, or receive information or data sent by other devices. The transceiver 630 may include a transmitter and a receiver. The transceiver 630 may further include an antenna, and the number of antennas may be one or more.

It should be understood that the various components in the terminal device 600 are connected by a bus system, where in addition to the data bus, the bus system also includes a power bus, a control bus, and a status signal bus.

It should also be understood that the terminal device 600 may be the terminal device of the embodiment of the present application, and the terminal device 600 may implement the corresponding process implemented by the terminal device in each method of the embodiment of the present application, that is, the terminal device of the embodiment of the present application The terminal device 600 may correspond to the terminal device 500 in the embodiment of the present application, and may correspond to a corresponding subject in executing the method 400 according to the embodiment of the present application. For brevity, details are not described herein again.

In addition, an embodiment of the present application also provides a chip.

For example, the chip may be an integrated circuit chip with signal processing capability, and can implement or execute the methods, steps, and logical block diagrams disclosed in the embodiments of the present application. The chip may also be called a system-level chip, a system-on-chip, a system-on-a-chip, or a system-on-chip. Optionally, the chip can be applied to various communication devices, so that the communication device installed with the chip can execute the methods, steps, and logical block diagrams disclosed in the embodiments of the present application.

FIG. 10 is a schematic structural diagram of a chip 700 according to an embodiment of the present application.

Please refer to FIG. 10, the chip 700 includes a processor 710.

The processor 710 may call and run a computer program from the memory to implement the method in the embodiment of the present application.

Please continue to refer to FIG. 10, the chip 700 may also include a memory 720.

The processor 710 may call and run a computer program from the memory 720 to implement the method in the embodiment of the present application. The memory 720 may be used to store instruction information, and may also be used to store codes and instructions executed by the processor 710. The memory 720 may be a separate device independent of the processor 710, or may be integrated in the processor 710.

Please continue to refer to FIG. 10, the chip 700 may further include an input interface 730.

The processor 710 can control the input interface 730 to communicate with other devices or chips, and specifically, can obtain information or data sent by other devices or chips.

Please continue to refer to FIG. 10, the chip 700 may further include an output interface 740.

The processor 710 can control the output interface 740 to communicate with other devices or chips, and specifically, can output information or data to other devices or chips.

It should be understood that the chip 700 can be applied to the terminal device in the embodiment of the present application, and the chip can implement the corresponding process implemented by the terminal device in the various methods of the embodiment of the present application. For the sake of brevity, details are not described herein again.

It should also be understood that the various components in the chip 700 are connected by a bus system, where in addition to the data bus, the bus system also includes a power bus, a control bus, and a status signal bus.

The processor may include, but is not limited to:

General-purpose processor, digital signal processor (Digital Signal Processor, DSP), Application Specific Integrated Circuit (ASIC), Field Programmable Gate Array (Field Programmable Gate Array, FPGA) or other programmable logic devices, discrete gates Or transistor logic devices, discrete hardware components, etc.

The processor may be used to implement or execute the methods, steps, and logical block diagrams disclosed in the embodiments of the present application. The steps of the method disclosed in the embodiments of the present application can be directly embodied as being executed and completed by a hardware decoding processor, or executed and completed by a combination of hardware and software modules in the decoding processor. The software module can be located in a mature storage medium in the field such as random access memory, flash memory, read-only memory, programmable read-only memory or erasable programmable memory, registers. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

The storage includes but is not limited to:

Volatile memory and/or non-volatile memory. Among them, the non-volatile memory can be read-only memory (Read-Only Memory, ROM), programmable read-only memory (Programmable ROM, PROM), erasable programmable read-only memory (Erasable PROM, EPROM), and electrically available Erase programmable read-only memory (Electrically EPROM, EEPROM) or flash memory. The volatile memory may be random access memory (Random Access Memory, RAM), which is used as an external cache. By way of exemplary but not restrictive description, many forms of RAM are available, such as static random access memory (Static RAM, SRAM), dynamic random access memory (Dynamic RAM, DRAM), synchronous dynamic random access memory (Synchronous DRAM, SDRAM), Double Data Rate Synchronous Dynamic Random Access Memory (Double Data Rate SDRAM, DDR SDRAM), Enhanced Synchronous Dynamic Random Access Memory (Enhanced SDRAM, ESDRAM), Synchronous Link Dynamic Random Access Memory (synch link DRAM), SLDRAM) and Direct Rambus RAM (DR RAM).

It should be noted that the memory described herein is intended to include these and any other suitable types of memory.

The embodiments of the present application also provide a computer-readable storage medium for storing computer programs. The computer-readable storage medium stores one or more programs, and the one or more programs include instructions that, when executed by a portable electronic device that includes multiple application programs, can cause the portable electronic device to execute the embodiment shown in the method Methods.

Optionally, the computer-readable storage medium can be applied to the network device in the embodiment of the present application, and the computer program causes the computer to execute the corresponding process implemented by the network device in each method of the embodiment of the present application. For the sake of brevity, here No longer.

Optionally, the computer-readable storage medium can be applied to the mobile terminal/terminal device in the embodiment of the present application, and the computer program causes the computer to execute the corresponding process implemented by the mobile terminal/terminal device in each method of the embodiment of the present application , For the sake of brevity, I won’t repeat it here.

The embodiments of the present application also provide a computer program product, including a computer program.

Optionally, the computer program product can be applied to the network device in the embodiment of the present application, and the computer program causes the computer to execute the corresponding process implemented by the network device in each method of the embodiment of the present application. For the sake of brevity, it will not be omitted here. Go into details.

Optionally, the computer program product can be applied to the mobile terminal/terminal device in the embodiment of the present application, and the computer program causes the computer to execute the corresponding process implemented by the mobile terminal/terminal device in each method of the embodiment of the present application, in order to It's concise, so I won't repeat it here.

A computer program is also provided in the embodiment of the present application. When the computer program is executed by the computer, the computer can execute the method of the illustrated embodiment of the method.

Optionally, the computer program can be applied to the network device in the embodiment of the present application. When the computer program runs on the computer, it causes the computer to execute the corresponding process implemented by the network device in each method of the embodiment of the present application. For the sake of brevity , I won’t repeat it here.

In addition, an embodiment of the present application also provides a communication system. The communication system may include the aforementioned terminal equipment and network equipment to form the communication system 100 as shown in FIG. 1. For brevity, details are not described herein again. It should be noted that the terms "system" in this article can also be referred to as "network management architecture" or "network system".

It should also be understood that the terms used in the embodiments of the present application and the appended claims are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application.

For example, the singular forms of "a", "said", "above" and "the" used in the embodiments of this application and the appended claims are also intended to include plural forms, unless the context clearly indicates other forms. meaning.

Those skilled in the art may be aware that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software depends on the specific application and design constraint conditions of the technical solution. Professionals and technicians can use different methods for each specific application to implement the described functions, but such implementation should not be considered as going beyond the scope of the embodiments of the present application.

If implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the embodiments of the present application are essentially or the part that contributes to the prior art or the part of the technical solutions can be embodied in the form of a software product, and the computer software product is stored in a storage medium. , Including several instructions to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the method described in the embodiments of the present application. The aforementioned storage media include: U disk, mobile hard disk, read-only memory, random access memory, magnetic disk or optical disk and other media that can store program codes.

Those skilled in the art can clearly understand that, for the convenience and conciseness of description, the specific working process of the system, device and unit described above can refer to the corresponding process in the foregoing method embodiment, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, device, and method may be implemented in other ways.

For example, the division of units or modules or components in the device embodiments described above is only a logical function division, and there may be other divisions in actual implementation. For example, multiple units or modules or components can be combined or integrated. To another system, or some units or modules or components can be ignored or not executed.

For another example, the aforementioned units/modules/components described as separate/display components may or may not be physically separated, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units/modules/components may be selected according to actual needs to achieve the objectives of the embodiments of the present application.

Finally, it should be noted that the mutual coupling or direct coupling or communication connection shown or discussed above may be indirect coupling or communication connection through some interfaces, devices or units, and may be in electrical, mechanical or other forms. .

The above content is only the specific implementation manners of the embodiments of the present application, but the protection scope of the embodiments of the present application is not limited thereto. Any person skilled in the art can easily think of within the technical scope disclosed in the embodiments of the present application. The change or replacement shall be covered within the protection scope of the embodiments of this application. Therefore, the protection scope of the embodiments of the present application should be subject to the protection scope of the claims.

Claims

A wireless communication method applied to terminal equipment, characterized in that it includes:

In the process of switching data transmission from the source network device to the target network device based on the dual activity protocol stack DAPS, if a switching command is received, the uplink packet data convergence protocol protocol data unit UL PDCP PDU transmission is switched from the source cell to the target cell.
The method according to claim 1, wherein the switching the uplink packet data convergence protocol data unit UL PDCP PDU transmission from the source cell to the target cell comprises:

If the handover command includes information for instructing the terminal device to ignore the random access channel RACH-Less, switch the UL PDCP PDU transmission from the source cell to the target cell.
The method according to claim 1, wherein the switching the uplink packet data convergence protocol data unit UL PDCP PDU transmission from the source cell to the target cell comprises:

If the handover command includes information for instructing the terminal device to ignore the random access channel RACH-Less and information for indicating pre-configured resources, the PDCP PDU transmission is switched from the source cell to the target cell.
The method according to claim 3, characterized in that said switching the uplink packet data convergence protocol data unit UL PDCP PDU transmission from the source cell to the target cell comprises:

Use the first available resource in the pre-configured resources to switch the UL PDCP PDU transmission from the source cell to the target cell.
The method according to claim 1, wherein the switching the uplink packet data convergence protocol data unit UL PDCP PDU transmission from the source cell to the target cell comprises:

If the handover command includes information for instructing the terminal device to ignore the random access channel RACH-Less and does not include information for instructing pre-configured resources, monitor the physical downlink control channel scrambled using the cell radio network temporary identifier C-RNTI PDCCH;

If the PDCCH scrambled with the C-RNTI is received, the UL PDCP PDU transmission is switched from the source cell to the target cell.
The method according to claim 5, wherein the PDCCH scrambled using the C-RNTI includes grant information for indicating uplink resources.
The method according to any one of claims 3 to 6, wherein the pre-configured resource is a shared resource of multiple terminal devices.
The method according to claim 7, characterized in that the switching of UL PDCP PDU transmission from the source cell to the target cell comprises:

If a successful contention resolution message is received, the UL PDCP PDU transmission is switched from the source cell to the target cell.
The method according to claim 8, wherein the method further comprises:

On the pre-configured resource, a cell radio network temporary identifier C-RNTI and a radio resource control RRC reconfiguration complete message are sent.
The method according to any one of claims 3 to 9, wherein the pre-configured resource is a periodic resource.
The method according to any one of claims 3 to 10, wherein the information used to indicate pre-configured resources includes at least one of the following information:

An identifier used to indicate the number of HARQ processes corresponding to the pre-configured resource;

The scheduling interval of the pre-configured resource;

The starting subframe number of the pre-configured resource; and

Information used to indicate resources for transmitting the physical uplink shared channel PUSCH.
The method according to any one of claims 3 to 11, wherein the information used to indicate the pre-configured resource is a periodic pre-configured uplink grant.
The method according to claim 1, wherein said switching the UL PDCP PDU transmission from the source cell to the target cell comprises:

If the handover command includes information for instructing the terminal equipment to adopt two-step random access, the UL PDCP PDU transmission is handed over from the source cell to the target cell.
The method according to claim 13, wherein the switching the uplink packet data convergence protocol data unit UL PDCP PDU transmission from the source cell to the target cell comprises:

If message A is successfully sent or message B is successfully received, the UL PDCP PDU transmission is switched from the source cell to the target cell.
A terminal device, characterized in that it comprises:

Transceiving unit and processing unit, in the process of switching data transmission from the source network device to the target network device based on the dual activity protocol stack DAPS, if the transceiving unit receives a switching command, the processing unit is used to aggregate uplink packet data The protocol data unit UL PDCP PDU transmission is switched from the source cell to the target cell.
The terminal device according to claim 15, wherein the processing unit is specifically configured to:

If the handover command includes information for instructing the terminal device to ignore the random access channel RACH-Less, switch the UL PDCP PDU transmission from the source cell to the target cell.
The terminal device according to claim 15, wherein the processing unit is more specifically configured to:

If the handover command includes information for instructing the terminal device to ignore the random access channel RACH-Less and information for indicating pre-configured resources, the PDCP PDU transmission is switched from the source cell to the target cell.
The terminal device according to claim 17, wherein the processing unit is more specifically configured to:

Use the first available resource in the pre-configured resources to switch the UL PDCP PDU transmission from the source cell to the target cell.
The terminal device according to claim 15, wherein the transceiving unit is further configured to:

If the handover command includes information for instructing the terminal device to ignore the random access channel RACH-Less and does not include information for instructing pre-configured resources, monitor the physical downlink control channel scrambled using the cell radio network temporary identifier C-RNTI PDCCH;

The processing unit is more specifically used for:

If the PDCCH scrambled with the C-RNTI is received, the UL PDCP PDU transmission is switched from the source cell to the target cell.
The terminal device according to claim 19, wherein the PDCCH scrambled using C-RNTI includes grant information for indicating uplink resources.
The terminal device according to any one of claims 17 to 20, wherein the pre-configured resource is a shared resource of multiple terminal devices.
The terminal device according to claim 21, wherein the processing unit is specifically configured to:

If a successful contention resolution message is received, the UL PDCP PDU transmission is switched from the source cell to the target cell.
The terminal device according to claim 22, wherein the transceiving unit is further configured to:

On the pre-configured resource, a cell radio network temporary identifier C-RNTI and a radio resource control RRC reconfiguration complete message are sent.
The terminal device according to any one of claims 17 to 23, wherein the pre-configured resource is a periodic resource.
The terminal device according to any one of claims 17 to 24, wherein the information used to indicate pre-configured resources includes at least one of the following information:

An identifier used to indicate the number of HARQ processes corresponding to the pre-configured resource;

The scheduling interval of the pre-configured resource;

The starting subframe number of the pre-configured resource; and

Information used to indicate resources for transmitting the physical uplink shared channel PUSCH.
The terminal device according to any one of claims 17 to 25, the information used to indicate the pre-configured resource is a periodic pre-configured uplink grant.
The terminal device according to claim 15, wherein the processing unit is specifically configured to:

If the handover command includes information for instructing the terminal equipment to adopt two-step random access, the UL PDCP PDU transmission is handed over from the source cell to the target cell.
The terminal device according to claim 27, wherein the processing unit is more specifically configured to:

If message A is successfully sent or message B is successfully received, the UL PDCP PDU transmission is switched from the source cell to the target cell.
A terminal device, characterized in that it comprises:

A processor, a memory, and a transceiver, where the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute the method according to any one of claims 1 to 13.
A chip, characterized in that it comprises:

The processor is configured to call and run a computer program from the memory, so that the device installed with the chip executes the method according to any one of claims 1 to 14.
A computer-readable storage medium, characterized in that it is used to store a computer program that enables a computer to execute the method according to any one of claims 1 to 14.
A computer program product, characterized by comprising computer program instructions, which cause a computer to execute the method according to any one of claims 1 to 14.
A computer program, wherein the computer program causes a computer to execute the method according to any one of claims 1 to 14.