CN112753249A

CN112753249A - Communication method and communication device

Info

Publication number: CN112753249A
Application number: CN201880097980.8A
Authority: CN
Inventors: 唐珣; 王宏; 张戬
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2018-09-27
Filing date: 2018-09-27
Publication date: 2021-05-04
Also published as: WO2020061871A1

Abstract

The application provides a communication method and a communication device. The communication method comprises the following steps: the source base station sends a switching command to the terminal equipment; the source base station receives a first instruction from the terminal equipment, the target base station or a core network element; in response to the first indication, the source base station sends a sequence number state transition message to the target base station. The communication method and the communication device can realize that the SN state transfer message is forwarded from the source base station to the target base station in the scene that the UE and the double base stations are simultaneously connected. In addition, the communication method and the communication device can save transmission resources.

Description

Communication method and communication device

Technical Field

The present application relates to the field of communications, and more particularly, to a communication method and a communication apparatus.

Background

In a cellular communication network, for example, in a Long Term Evolution (LTE) communication system, when a terminal equipment (UE) moves, the UE may perform handover of a serving base station according to a change in signal strength.

After receiving the handover command, the UE disconnects Radio Resource Control (RRC) connection with the source base station. The UE may then start a random access procedure for the target base station. After the UE sends the handover complete message to the target base station, the UE resumes the RRC connection (i.e., the RRC connection with the target base station). During this handover, the data transmission of the UE is interrupted. And after the source base station sends the switching command to the UE, the source base station immediately forwards the data of the UE to the target base station.

In order to reduce the interruption time of data transmission of the UE during handover, a pre-interruption (MBB) technique is developed. The MBB technology refers to: after receiving the switching command, the UE does not immediately interrupt the RRC connection with the source base station, but continues to maintain the RRC connection with the source base station until the first uplink transmission time of the UE for the target base station. Specifically, after receiving the handover command, the UE still maintains communication with the source base station until the UE transmits the random access preamble to the target base station. Therefore, the data transmission of the UE is interrupted only in the process of random access between the UE and the target base station, and the interruption time of the data transmission of the UE is reduced.

Further, enhanced MBB techniques are presented. In the enhanced MBB technique, a UE is simultaneously connected with a source base station and a target base station. Specifically, even during the random access process of the UE with the target base station, the connection of the UE with the source base station is not interrupted. Thus, in the process of handover, there is a period of time when the UE keeps connection with the source base station and the target base station simultaneously, and data transmission can also be performed simultaneously. In the enhanced MBB technology, the UE is simultaneously connected with the source base station and the target base station, which may also be referred to as the UE being simultaneously connected with the dual base stations.

In a scenario where the UE is simultaneously connected to the dual base stations, the source base station needs to send a Serial Number (SN) status transfer message to the target base station, so that the target base station sends, to the UE, UE data forwarded from the source base station to the target base station according to the SN status transfer message, and so that the target base station confirms an uplink missing data packet SN.

However, in a scenario where the UE is simultaneously connected to the dual base stations, the prior art does not design in detail a sending manner of the SN status transfer message, that is, how to forward the SN status transfer message from the source base station to the target base station. Therefore, in a scenario where the UE is connected to the dual base stations at the same time, how to forward the SN status transfer message from the source base station to the target base station is an urgent technical problem to be solved.

Disclosure of Invention

The application provides a communication method and a communication device. The communication method and the communication device can realize that the SN state transfer message is forwarded from the source base station to the target base station in the scene that the UE and the double base stations are simultaneously connected.

In a first aspect, the present application provides a communication method, including: the source base station sends a switching command to the terminal equipment; the source base station receives a first instruction from the terminal equipment, the target base station or a core network element; in response to the first indication, the source base station sends a sequence number state transition message to the target base station.

In the communication method, the source base station may receive a first indication from the terminal device, the target base station, or a core network element, so that the source base station may send an SN status transfer message to the target base station in response to the first indication. That is, the communication method may enable forwarding of the SN status transfer message from the source base station to the target base station.

In addition, because the source base station sends the SN status transfer message to the target base station only under the instruction of the first instruction sent by the terminal device, the target base station or the core network element, when the source base station receives the first instruction after the terminal device starts the random access process for the target base station or the terminal device completes the random access process for the target base station, the time point of sending the SN status transfer message to the target base station by the source base station is delayed compared with the traditional sending event of the SN status transfer message, so that the time point of data communication between the target base station and the terminal device can be delayed, and further, the transmission resource between the target base station and the terminal device can be saved.

The later the time point when the source base station receives the first indication is, the more transmission resources between the terminal device and the target base station can be saved.

In one possible implementation, the communication method further includes: and responding to the first indication, and initiating data forwarding of the terminal equipment to the target base station by the source base station.

That is to say, the source base station initiates data forwarding of the terminal device to the target base station only under the trigger of the first indication, so that the time point when the source base station initiates data forwarding of the terminal device to the target base station can be delayed, and further transmission resources between the source base station and the target base station can be saved.

The later the time point when the source base station receives the first indication is, the more transmission resources between the source base station and the target base station can be saved.

In a possible implementation manner, the receiving, by the source base station, the first indication from the terminal device, the target base station, or a network element of a core network includes: the source base station receives the first indication from the terminal device, the target base station, or the core network element after the terminal device completes a random access procedure for the target base station.

In a possible implementation manner, when the source base station receives the first indication from the terminal device, the first indication is carried in a radio resource control message or a media access layer control unit, or the first indication is a physical layer dedicated indication.

In a possible implementation manner, when the source base station receives the first indication from the core network element, the first indication is an end indicator.

In a possible implementation manner, the data forwarding includes uplink data forwarding, or the data forwarding includes downlink data forwarding, or the data forwarding includes uplink data forwarding and downlink data forwarding.

In a second aspect, the present application provides a communication method, comprising: the target base station receives a switching request message from the source base station; the target base station receives a random access lead code from terminal equipment; the target base station sends a first instruction to the source base station, wherein the first instruction is used for triggering the source base station to send a serial number state transition message to the target base station; the target base station receives the sequence number state transition message from the source base station.

In the communication method, the target base station sends the first indication to the source base station, so that the source base station can send the SN state transfer message to the target base station in response to the first indication, that is, the transmission of the SN state transfer message from the source base station to the target base station can be realized.

In addition, the target base station transmits the first indication to the source base station after receiving the random access preamble from the terminal device, so that the source base station can transmit the SN status transfer message to the target base station after the terminal device starts random access. Because the target base station performs data communication with the terminal device after receiving the SN state transfer message, the communication method can delay the time point when the target base station performs data communication with the terminal device, thereby saving transmission resources between the target base station and the terminal device.

The later the time point when the target base station sends the first indication to the source base station, the more transmission resources between the terminal device and the target base station can be saved.

In a possible implementation manner, the first indication is further used to trigger the source base station to initiate data forwarding of the terminal device to the target base station. Wherein the communication method further comprises: and the target base station receives the data of the terminal equipment from the source base station.

The implementation method enables the source base station to initiate the data forwarding of the terminal device to the target base station only under the triggering of the first indication, so that the time point when the source base station initiates the data forwarding of the terminal device to the target base station can be delayed, and further, the transmission resources between the source base station and the target base station can be saved.

The later the time point when the target base station sends the first indication to the source base station, the more transmission resources between the source base station and the target base station can be saved.

In one possible implementation manner, the sending, by the target base station, the first indication to the source base station includes: the target base station receives a switching completion message or a reconfiguration completion message from the terminal equipment; and the target base station responds to the switching completion message or the reconfiguration completion message and sends the first indication to the source base station.

In one possible implementation manner, the sending, by the target base station, the first indication to the source base station includes: the target base station sends the first indication to the source base station in response to the random access preamble.

In a third aspect, the present application provides a communication method, including: the terminal equipment receives a switching command from a source base station; the terminal equipment sends a random access lead code to a target base station; and the terminal equipment sends a first instruction to the source base station, wherein the first instruction is used for triggering the source base station to send a serial number state transition message to the target base station.

In the communication method, the terminal device sends the first indication to the source base station, so that the source base station can send the SN state transfer message to the target base station in response to the first indication, that is, the transmission of the SN state transfer message from the source base station to the target base station can be realized.

In addition, the terminal device sends the first indication to the source base station after sending the random access preamble, so that the source base station can send the SN status transfer message to the target base station after the terminal device starts random access. Because the target base station performs data communication with the terminal device after receiving the SN state transfer message, the communication method can delay the time point when the target base station performs data communication with the terminal device, thereby saving transmission resources between the target base station and the terminal device.

The later the time point when the terminal equipment sends the first indication to the source base station is, the more transmission resources between the terminal equipment and the target base station can be saved.

In a possible implementation manner, the first indication is further used to trigger the source base station to initiate data forwarding of the terminal device to the target base station.

The later the time point when the terminal equipment sends the first indication to the source base station is, the more transmission resources between the source base station and the target base station can be saved.

In a possible implementation manner, the sending, by the terminal device, a first indication to the source base station includes: the terminal equipment receives a random access response message from the target base station equipment; and responding to the random access response message, and sending the first indication to the source base station by the terminal equipment.

In a possible implementation manner, the sending, by the terminal device, a first indication to the source base station includes: the terminal equipment receives a competition resolving message from the target base station equipment; and responding to the competition resolving message, and sending the first indication to the source base station by the terminal equipment.

In a possible implementation manner, the sending, by the terminal device, a first indication to the source base station includes: the terminal equipment receives scheduling information scrambled by using a cell radio network temporary identifier of the terminal equipment from the target base station equipment; and responding to the scheduling information, and the terminal equipment sends the first indication to the source base station.

In a possible implementation manner, the first indication is carried in a radio resource control message or a medium access layer control element, or the first indication is a physical layer dedicated indication.

In one possible implementation, the communication method further includes: the terminal equipment determines to send uplink data to the source base station or the target base station according to the specification of a communication protocol; or the terminal equipment receives a second instruction from the source base station or the target base station and responds to the second instruction to determine to send uplink data to the source base station or the target gesture; or the terminal equipment determines to send uplink data to the source base station or the target base station according to the signal quality between the source base station and the terminal equipment or the signal quality between the target base station and the terminal equipment.

In a fourth aspect, an embodiment of the present application provides a communication method, where the communication method includes: a core network element receives a modification bearing request message; and the core network element sends a first instruction to the source base station, wherein the first instruction is used for triggering the source base station to send the SN state transfer message to the target base station.

In the communication method, the core network element sends the first indication to the source base station, so that the source base station can send the SN state transfer message to the target base station in response to the first indication, that is, the transmission of the SN state transfer message from the source base station to the target base station can be realized.

In addition, the core network element sends the first indication to the source base station after the terminal device completes the random access process, so that the source base station can send the SN status transfer message to the target base station after the terminal device completes the random access. Because the target base station performs data communication with the terminal device after receiving the SN state transfer message, the communication method can delay the time point when the target base station performs data communication with the terminal device, thereby saving transmission resources between the target base station and the terminal device.

The later the time point when the core network element sends the first indication to the source base station, the more transmission resources between the terminal device and the target base station can be saved.

The later the time point when the core network element sends the first indication to the source base station, the more transmission resources between the source base station and the target base station can be saved.

In one possible implementation, the first indication may be an end marker.

In a fifth aspect, the present application provides a communication device. The communication device comprises means for performing the communication method of the first aspect or any one of the possible implementations of the first aspect. The communication device comprises modules which can be implemented by software and/or hardware.

Alternatively, the communication device may be a base station, or may be a chip that can be integrated in a base station.

In a sixth aspect, the present application provides a communication device. The communication device comprises means for performing the second aspect or the communication method in any one of the possible implementations of the second aspect. The communication device comprises modules which can be implemented by software and/or hardware.

In a seventh aspect, the present application provides a communication device. The communication device comprises means for performing the communication method of the third aspect or any one of its possible implementations. The communication device comprises modules which can be implemented by software and/or hardware.

Alternatively, the communication means may be a terminal device, or may be a chip that can be integrated in a terminal device.

In an eighth aspect, the present application provides a communication device. The communication device comprises means for performing the communication method of the fourth aspect or any one of the possible implementations of the fourth aspect. The communication device comprises modules which can be implemented by software and/or hardware.

Alternatively, the communication device may be a core network element, or may be a chip that can be integrated in a core network element.

In a ninth aspect, the present application provides a computer-readable storage medium. The computer readable storage medium has stored therein program code for execution by the communication device. The program code comprises instructions for performing the communication method of the first aspect or any one of the possible implementations of the first aspect.

In a tenth aspect, the present application provides a computer-readable storage medium. The computer readable storage medium has stored therein program code for execution by the communication device. The program code comprises instructions for carrying out the second aspect or the communication method in any one of the possible implementations of the second aspect.

In an eleventh aspect, the present application provides a computer-readable storage medium. The computer readable storage medium has stored therein program code for execution by the communication device. The program code comprises instructions for performing the communication method of the third aspect or any one of the possible implementations of the third aspect.

In a twelfth aspect, the present application provides a computer-readable storage medium. The computer readable storage medium has stored therein program code for execution by the communication device. The program code comprises instructions for performing the communication method of the fourth aspect or any one of the possible implementations of the fourth aspect.

In a thirteenth aspect, the present application provides a computer program product containing instructions. The computer program product, when run on a communication apparatus, causes the communication apparatus to implement the communication method of the first aspect or any one of the possible implementations of the first aspect.

In a fourteenth aspect, the present application provides a computer program product containing instructions. The computer program product, when run on a communication apparatus, causes the communication apparatus to implement the communication method of the second aspect or any one of the possible implementations of the second aspect.

In a fifteenth aspect, the present application provides a computer program product containing instructions. The computer program product, when run on a communication apparatus, causes the communication apparatus to implement the communication method of the third aspect or any one of the possible implementations of the third aspect.

In a sixteenth aspect, the present application provides a computer program product comprising instructions. The computer program product, when run on a communication apparatus, causes the communication apparatus to implement the communication method of the fourth aspect or any one of the possible implementations of the fourth aspect.

Drawings

Fig. 1 is a schematic architecture diagram of a communication system to which the communication method of the embodiment of the present application can be applied;

fig. 2 is a schematic flow chart of a handover procedure to which the communication method of the embodiment of the present application can be applied;

FIG. 3 is a schematic flow chart diagram of a communication method of one embodiment of the present application;

FIG. 4 is a schematic flow chart diagram of a communication method of another embodiment of the present application;

FIG. 5 is a schematic flow chart diagram of a communication method of another embodiment of the present application;

FIG. 6 is a schematic flow chart diagram of a communication method of another embodiment of the present application;

FIG. 7 is a schematic flow chart diagram of a communication method of another embodiment of the present application;

FIG. 8 is a schematic flow chart diagram of a communication method of another embodiment of the present application;

FIG. 9 is a schematic block diagram of a protocol stack of one embodiment of the present application;

FIG. 10 is a schematic block diagram of a communication device according to an embodiment of the present application;

fig. 11 is a schematic configuration diagram of a communication apparatus of another embodiment of the present application;

fig. 12 is a schematic configuration diagram of a communication apparatus of another embodiment of the present application;

fig. 13 is a schematic configuration diagram of a communication apparatus of another embodiment of the present application;

fig. 14 is a schematic configuration diagram of a communication apparatus according to another embodiment of the present application.

Detailed Description

The technical solution in the present application will be described below with reference to the accompanying drawings.

The technical scheme of the embodiment of the application can be applied to various communication systems, for example: an LTE system, an LTE Frequency Division Duplex (FDD) system, an LTE Time Division Duplex (TDD), a future fifth generation (5G) system, a New Radio (NR) system, a communication system in which a Central Unit (CU) and a Distributed Unit (DU) are separated, or a communication system in which two or more of the above systems are combined.

A UE in the embodiments of the present application may refer to a terminal device, an access terminal, a subscriber unit, a subscriber station, a mobile station, a remote terminal, a mobile device, a user terminal, a wireless communication device, a user agent, or a user equipment. The UE may also be a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a flight-capable device (e.g., a drone or a hot-air balloon), a terminal device in a future 5G network or a terminal device in a future evolved Public Land Mobile Network (PLMN), and the like, which are not limited in this embodiment.

A base station (e.g., access point) in embodiments of the present application may refer to a device in an access network that communicates over the air-interface, through one or more sectors, with terminal devices. The base station may be an evolved NodeB (eNB) or eNodeB in an LTE system, or the network device may be a gNB or the like in a future 5G system or an NR system, which is not limited in the embodiment of the present invention.

The core network element in this embodiment may include a Serving Gateway (SGW) or a User Plane Function (UPF) network element.

Fig. 1 is an exemplary architecture diagram of a communication system according to one embodiment of the present application. The method in the embodiment of the present application may be applied to the communication system shown in fig. 1. It should be understood that more or fewer network elements or devices may be included in a communication system to which the methods of the embodiments of the present application may be applied.

The devices or network elements in fig. 1 may be hardware, or may be functionally divided software, or a combination of the two. The devices or network elements in fig. 1 may communicate with each other through other devices or network elements.

The communication system shown in fig. 1 may include a source base station 110, a target base station 120, and a terminal device 130.

The source base station 110, the target base station 120 and the terminal device 130 may communicate with each other. For example, the source base station 110 and the target base station 120 may communicate through an X2 interface, or communicate through a core network device, and the target base station 110 and the target base station 120 may communicate with the terminal device 130 through an air interface, or communicate through a relay device, respectively.

The source base station 110 and the target base station 120 may be the same type of network device, for example, the source base station 110 and the target base station 120 are enbs; or the target base station 110 and the target base station 120 may be different types of network devices, for example, the source base station 110 is an eNB and the target base station 120 is a gNB.

In the communication system shown in fig. 1, the terminal device 130 may be handed over from the source base station 110 to the target base station 120. The cell in which the source base station 110 provides service for the terminal device 130 is referred to as a source cell, and the cell in which the target base station 120 provides service for the terminal device 130 is referred to as a target cell.

In the embodiments of the present application, the source base station and the source cell may be interchanged, and the target base station and the target cell may be interchanged.

A schematic flow diagram of a handover procedure in the communication system shown in fig. 1 is shown in fig. 2. It should be understood that fig. 2 shows steps or operations of the handover procedure, but these steps or operations are only examples, and other operations or variations of the operations in fig. 2 may also be performed in the embodiments of the present application, or all the steps or operations in fig. 2 may not be performed in the embodiments of the present application.

S201, the source base station configures measurement control information to the terminal device, so that the terminal device performs measurement to assist the source base station in controlling a mobility function under connection.

S202, the terminal equipment measures according to the frequency point information configured by the source base station, evaluates according to the configured measurement report criterion, and reports the measurement report to the source base station.

S203, the source base station makes switching judgment according to the result reported by the terminal equipment and some information maintained by the source base station.

S204, the source base station transmits necessary information for Handover preparation at the target base station side to the target base station through a Handover Request (Handover Request) message.

And S205, the target base station makes an access permission judgment according to the quality of service (Qos) information.

S206, the target base station replies a Handover Request acknowledgement (Handover Request Ack) message to the source base station.

S207, the source base station sends a switching command to the terminal equipment. The handover command may also be referred to as a handover message.

S208, the terminal equipment sends the random access lead code to the target base station.

S209, the target base station sends a random access response message to the terminal device.

S210, the terminal equipment sends a switching completion message to the target base station. The handover complete message may also be referred to as a reconfiguration complete message.

After receiving the handover complete message sent by the terminal device, the target base station may perform data transmission with the terminal device.

S211, the target base station switches the confirmation message to the terminal equipment. The handover confirmation message may also be a contention resolution message. S211 is an optional step.

Wherein, S208 to S211 together may be referred to as a random access procedure.

S212, the target base station sends a Path Switch Request (Path Switch Request) message to a Mobility Management Entity (MME).

S213, the MME sends a Modify bearer Request (Modify bearer Request) message to the Serving Gateway (SGW).

And S214, switching paths by the SGW. For example, the SGW switches the downstream path.

S215, the SGW sends an End Marker (End Marker) to the source base station.

S216, the source base station sends an end mark to the target base station.

S217, the SGW sends a Modify bearer Response (Modify bearer Response) message to the MME.

S218, the MME sends a Path Switch Request Ack message to the target base station.

S219, the target base station sends a terminal device Context Release (UE Context Release) message to the source base station.

S220, the source base station releases the resources used for communication with the terminal equipment.

It should be understood that the handover procedure shown in fig. 2 is only an example, and the communication method according to the embodiment of the present application is not limited to be applied only to the handover procedure shown in fig. 2.

In the process of switching the terminal device from the source base station to the target base station, the terminal device can be connected with the target base station and the target base station at the same time. For example, even after the terminal device transmits the random access preamble to the source base station, the connection of the terminal device with the source base station is not interrupted during the random access procedure with the target base station.

During the time when the terminal device is connected to the source base station and the target base station at the same time, the terminal device can perform data transmission with the source base station and the target base station at the same time.

In the process of switching the terminal equipment from the source base station to the target base station, if the terminal equipment is simultaneously connected with the source base station and the target base station, the source base station initiates data forwarding of the terminal equipment to the target base station and sends an SN state transfer message to the target base station.

In some possible implementations, the source base station may initiate data forwarding of the terminal device to the target base station and send an SN status transfer message to the target base station immediately after sending the handover command to the terminal device.

In the embodiments of the present application, the data forwarding may include uplink data forwarding, or downlink data forwarding, or both uplink data forwarding and downlink data forwarding.

In an embodiment of the present application, forwarding downlink data may include: forwarding a Packet Data Convergence Protocol (PDCP) Packet Data Unit (PDU) which has been sent by the source base station to the terminal device but has not been successfully transmitted, or forwarding new data from the core network to which a Sequence Number (SN) is not assigned by the source base station, or forwarding the PDCP PDU and the new data.

In an embodiment of the present application, forwarding uplink data may include: the source base station does not forward an uplink PDCP Service Data Unit (SDU) sent to the core network device.

In the embodiment of the present application, a specific procedure for sending data forwarding of a terminal device to a target base station by a source base station may refer to a procedure in the prior art, which is not described herein again.

In the embodiment of the present application, the SN status transfer message may include one or more of indication information for indicating a serial number status of data that is not transmitted to the terminal device by the source base station, indication information for indicating a serial number status of data that has been transmitted to the terminal device by the source base station but has not been successfully transmitted, or indication information for indicating a serial number SN status of data received from the terminal device by the source base station.

For example, the SN status transfer message may include indication information indicating a count (count or SN) value that should be allocated by the target base station for a first new data packet downlink from the terminal device, and/or may include indication information indicating a count value of a first unsuccessful data packet uplink from the terminal device, and/or bitmap (bitmap) information of subsequent successful and unsuccessful data packets, where a bit "1" indicates successful transmission and a bit "0" indicates unsuccessful transmission.

For example, if the data forwarding includes downlink data forwarding, the SN status transfer message may include indication information (SN of the first PDCP PDU that needs to be sent) for indicating a status of a sequence number of data that is not sent to the terminal device by the source base station and/or indication information for indicating a status of a sequence number of data that has been sent to the terminal device by the source base station but has not been successfully sent.

For example, if the data forwarding includes uplink data forwarding, the SN status transfer message may include indication information for indicating a sequence number SN status of data received by the source base station from the terminal device.

For example, if the data forwarding includes both uplink data forwarding and downlink data forwarding, the SN status transfer message may include at least one of indication information for indicating a status of a sequence number of data that is not transmitted to the terminal device by the source base station and indication information for indicating a status of a sequence number of data that has been transmitted to the terminal device by the source base station but has not been successfully transmitted, and may include indication information for indicating a status of a sequence number SN of data that is received from the terminal device by the source base station.

If the source base station immediately initiates data forwarding of the terminal device and sends an SN state transfer message to the target base station after sending the handover command to the terminal device, the target base station may send downlink data to the terminal device and/or send uplink data of the terminal device to the core network device after receiving the data forwarded by the source base station and the SN state transfer message.

However, in a scenario where the terminal device is connected to the source base station and the target base station at the same time, after the source base station sends the handover command to the terminal device, the source base station may still send downlink data to the terminal device, so that it is unnecessary for the source base station to send the SN status transfer message to the target base station immediately after sending the handover command to the terminal device, so that the target base station may send data received from the source base station to the terminal device according to the SN status transfer message.

Similarly, since the source base station can still receive the uplink data from the terminal device after sending the handover command to the terminal device, it is not necessary that the source base station sends the SN status transfer message to the target base station immediately after sending the handover command to the terminal device, so that the target base station can receive the uplink data from the terminal device according to the SN status transfer message.

As can be seen from the above analysis, after the source base station sends the handover command to the terminal device, the source base station immediately sends the SN status transfer message to the target base station, which may cause a waste of transmission resources between the target base station and the terminal device.

In view of the above problem of the waste of transmission resources, the present application provides a new communication method, which can delay the time point when the source base station sends the SN status transfer message to the target base station, so as to reduce the waste of transmission resources between the target base station and the terminal device.

Fig. 3 is a schematic flow chart of a communication method according to an embodiment of the present application. It should be understood that fig. 3 shows steps or operations of the communication method, but these steps or operations are only examples, and the embodiments of the present application may also perform other operations or variations of the respective operations in fig. 3, or the embodiments of the present application may not perform all the steps or operations in fig. 3.

S310, the source base station sends a switching request message to the target base station. Accordingly, the target base station receives a handover request message from the source base station. The handover request message is used for applying for access resources of the terminal device from the target base station and providing configuration information of the terminal device.

For example, this step may be S204 in the handover procedure shown in fig. 2.

S320, the terminal equipment sends and receives the random access lead code to the target base station. Accordingly, the target base station receives the random access preamble from the terminal device. The random access preamble refers to a predetermined sequence.

For example, this step may be S208 in the handover procedure shown in fig. 2.

Optionally, steps identical or similar to at least one of steps S205 to S207 may be included between S310 to S320.

S330, the target base station sends a first instruction to the source base station, wherein the first instruction is used for triggering the source base station to send the SN state transfer message to the target base station. Accordingly, the source base station receives the first indication from the target base station.

The target base station may send the first indication to the source base station at any time after receiving the random access preamble sent by the terminal device and before sending the path switching request message to the core network element. The path switching request message is used for establishing a data channel between the target base station and the network element of the core network.

Taking the handover procedure shown in fig. 2 as an example, the target base station may send the first indication to the source base station at any time between S208 and S212.

For example, after the target base station receives the random access preamble from the terminal device, the first indication may be sent to the source base station in response to the random access preamble.

For example, the target base station may send the first indication to the source base station immediately after sending the random access response message to the terminal device. The random access response message is used to confirm that the base station received the random access preamble.

For example, after receiving the handover complete message or the reconfiguration complete message from the terminal device, the target base station may send the first indication to the source base station in response to the handover complete message or the reconfiguration complete message. The handover complete message indicates that the UE has completed the handover configuration.

For example, the target base station may send the first indication to the source base station immediately after sending the handover confirm message or the contention resolution message to the terminal device. The handover confirmation message or the contention resolution message is used to confirm to the terminal device that the target base station has received the handover completion message sent by the terminal device.

The target base station may send a first indication to the source base station over an X2 interface. For example, a dedicated message may be newly added between the target base station and the source base station, and the first indication may be carried in the dedicated message. In this way, the target base station may send the first indication to the source base station by sending the dedicated message to the source base station.

S340, the source base station responds to the first indication and sends the SN state transfer message of the terminal equipment to the target base station. Accordingly, the target base station receives the SN status transfer message from the source base station.

If the SN status transfer message includes indication information for indicating the serial number status of downlink data that is not sent to the terminal device by the source base station and/or indication information for indicating the serial number status of downlink data that has been sent to the terminal device by the source base station but has not been successfully sent, the target base station may determine, according to the indication information included in the SN status transfer message, an SN or a count number corresponding to a first downlink data packet that needs to be sent to the terminal device.

If the SN status transfer message includes indication information for indicating the SN status of the uplink data received by the source base station from the terminal device, the target base station may determine, according to the indication information included in the SN status transfer message, an SN or a count number corresponding to an uplink data packet that needs to be received from the terminal device.

The target base station will not transmit the data to the terminal device until the SN or the count number of the data of the terminal device is determined. The target base station determines the SN or the count number of the data of the terminal device according to the SN state transfer message, and refers to a related implementation manner in the prior art, which is not described herein again.

In summary, the communication method shown in fig. 3 can be summarized as: after the terminal device starts a random access process for the target base station, the target base station sends a first indication to the source base station, and the source base station sends an SN state transfer message of the terminal device to the target base station under the trigger of the first indication. The communication method enables the source base station to send the SN state transfer message of the terminal equipment to the target base station after the terminal equipment starts the random access process aiming at the target base station.

Compared with the method in which the source base station immediately sends the SN status transfer message to the target base station after sending the handover command to the terminal device, the communication method shown in fig. 3 can delay the time point of data communication between the target base station and the terminal device because the time point of sending the SN status transfer message to the target base station by the source base station is delayed, and thus can reduce the waste of transmission resources between the target base station and the terminal device.

Fig. 4 is a schematic flow chart of a communication method according to another embodiment of the present application. It should be understood that fig. 4 shows steps or operations of the communication method, but these steps or operations are only examples, and the embodiments of the present application may also perform other operations or variations of the respective operations in fig. 4, or the embodiments of the present application may not perform all the steps or operations in fig. 4.

S410, the source base station sends a switching command to the terminal equipment. Accordingly, the terminal device receives a handover command from the source base station. The handover command is used to provide configuration information of the target cell.

For example, this step may be S207 in the handover procedure shown in fig. 2.

S420, the terminal equipment sends a random access preamble to the target base station. Accordingly, the target base station receives the random access preamble from the terminal device.

For example, this step may be S208 in the handover procedure shown in fig. 2.

Optionally, steps identical or similar to at least one of steps S205 to S207 may be included between S410 to S420.

S430, the terminal device sends a first instruction to the source base station, and the first instruction is used for triggering the source base station to send an SN state transfer message to the target base station. Accordingly, the source base station receives the first indication from the terminal device.

In some possible implementations, the terminal device may send the first indication to the source base station immediately after sending the random access preamble to the target base station.

In some possible implementations, after receiving the random access response message from the target base station, the terminal device may send a first indication to the source base station in response to the random access response message.

In some possible implementations, after the terminal device sends the handover complete message or the reconfiguration complete message to the target base station, the terminal device may send the first indication to the source base station immediately.

In some possible implementations, after receiving the handover confirmation message or the contention resolution message from the target base station, the terminal device may send the first indication to the source base station in response to the handover confirmation message or the contention resolution message. The handover confirmation message or the contention resolution message is used to confirm to the terminal device that the target base station has received the handover completion message sent by the terminal device.

In some possible implementations, after receiving, by the terminal device from the target base station, scheduling information scrambled using a cell radio network temporary identifier (C-RNTI) of the terminal device, the terminal device may send a first indication to the source base station in response to the scheduling information.

In this embodiment, the terminal device may send a dedicated message to the source base station, where the dedicated message carries the first indication. The dedicated message may be referred to as a forwarding request message, an access confirmation message, or the like, and the specific name is not limited. The dedicated message may be transmitted over the air.

In this embodiment of the application, the first indication may be carried in an RRC message or a Media Access Control (MAC) Control Element (CE), or the first indication may be a physical layer dedicated indication.

S440, the source base station responds to the first indication and sends the SN state transfer message of the terminal equipment to the target base station. Accordingly, the target base station receives the SN status transfer message from the source base station.

In summary, the communication method shown in fig. 4 may be summarized as: after the terminal device starts a random access process for the target base station, the terminal device sends a first indication to the source base station, and the source base station sends an SN state transfer message of the terminal device to the target base station under the trigger of the first indication. The communication method enables the source base station to send the SN state transfer message of the terminal equipment to the target base station after the terminal equipment starts the random access process aiming at the target base station.

Compared with the method in which the source base station immediately sends the SN status transfer message to the target base station after sending the handover command to the terminal device, the communication method shown in fig. 4 can delay the time point of data communication between the target base station and the terminal device because the time point of sending the SN status transfer message to the target base station by the source base station is delayed, and thus can reduce the waste of transmission resources between the target base station and the terminal device.

Fig. 5 is a schematic flow chart of a communication method according to another embodiment of the present application. It should be understood that fig. 5 shows steps or operations of the communication method, but these steps or operations are only examples, and the embodiments of the present application may also perform other operations or variations of the respective operations in fig. 5, or the embodiments of the present application may not perform all the steps or operations in fig. 5.

S510, the core network element receives the modify bearer request message. The modified bearer request message is used for establishing a data channel between the core network element and the target base station.

An example of the core network element is an SGW, but other network elements or devices having functions similar to those of the SGW may also be used, and the embodiments of the present application do not limit this.

An example of this step is S213 in the handover procedure shown in fig. 2.

S520, the core network element sends a first instruction to the source base station, and the first instruction is used for triggering the source base station to send an SN state transfer message to the target base station. Accordingly, the source base station receives a first indication from a core network element.

In some possible implementations, the core network device may send a dedicated message to the source base station, where the dedicated message carries the first indication. The specific name of the dedicated message is not limiting.

In some possible implementations, the first indication may be an End Marker (End Marker). The end-marker carrying packet usually contains no data, and the header of a GPRS Tunneling Protocol (GTP) tunnel indicates that the packet is an end-marker packet. The end-marker or end-marker packet is used to indicate the end of data transmission on the corresponding GTP tunnel. The GPRS is a short for general packet radio service (general packet radio service).

S530, the source base station responds to the first indication and sends the SN state transfer message of the terminal equipment to the target base station. Accordingly, the target base station receives the SN status transfer message from the source base station.

In summary, the communication method shown in fig. 5 may be summarized as: after the terminal equipment completes the random access process aiming at the target base station, the core network element sends a first indication to the source base station, and the source base station sends an SN state transfer message of the terminal equipment to the target base station under the trigger of the first indication. The communication method enables the source base station to send the SN state transfer message of the terminal equipment to the target base station after the terminal equipment completes the random access process aiming at the target base station.

Compared with the method in which the source base station immediately sends the SN status transfer message to the target base station after sending the handover command to the terminal device, the communication method shown in fig. 5 can delay the time point of data communication between the target base station and the terminal device because the time point of sending the SN status transfer message to the target base station by the source base station is delayed, and thus can reduce the waste of transmission resources between the target base station and the terminal device.

For any of the communication methods shown in fig. 3 to 5, in some possible implementations, the source base station may initiate data forwarding of the terminal device to the target base station immediately after sending the handover command to the terminal device. Of course, the source base station may also initiate data forwarding of the terminal device to the target base station at other times, and the time when the source base station initiates data forwarding of the terminal device is not limited in the embodiment of the present application.

In other possible implementations, the first indication may also be used to trigger the source base station to initiate data forwarding (data forwarding) of the terminal device to the target base station. Accordingly, in response to the first indication, the source base station may initiate data forwarding for the terminal device to the target base station.

For example, as shown in fig. 6, after S330, i.e., after the source base station receives the first indication from the target base station, the communication method may further include S350, in which the source base station initiates data forwarding of the terminal device to the target base station in response to the first indication.

It should be understood that the same reference numerals in fig. 6 as in fig. 3 denote the same or similar meanings, and thus, for brevity, will not be described again here. In addition, the communication method shown in fig. 6 does not limit the execution sequence between S340 and S350.

In the communication method shown in fig. 6, the source base station initiates data forwarding of the terminal device after the terminal device starts to access the target base station. Compared with the method that the data forwarding of the terminal equipment is initiated to the target base station immediately after the source base station sends the switching command to the terminal equipment, the method has the advantage that the time point of initiating the data forwarding of the terminal equipment to the target base station by the source base station is delayed, so that the waste of transmission resources between the source base station and the target base station can be reduced.

For example, as shown in fig. 7, after S430, that is, after the source base station receives the first indication from the terminal device, the communication method may further include S450, in which the source base station initiates data forwarding of the terminal device to the target base station in response to the first indication.

It should be understood that the same reference numerals in fig. 7 as in fig. 4 denote the same or similar meanings, and thus, for brevity, will not be described again here. In addition, the communication method shown in fig. 7 does not limit the execution sequence between S440 and S450.

In the communication method shown in fig. 7, the source base station initiates data forwarding of the terminal device after the terminal device starts to access the target base station. Compared with the method that the data forwarding of the terminal equipment is initiated to the target base station immediately after the source base station sends the switching command to the terminal equipment, the method has the advantage that the time point of initiating the data forwarding of the terminal equipment to the target base station by the source base station is delayed, so that the waste of transmission resources between the source base station and the target base station can be reduced.

For example, as shown in fig. 8, after S520, that is, after the source base station receives the first indication from the core network element, the communication method may further include S540, in which the source base station initiates data forwarding of the terminal device to the target base station in response to the first indication.

It should be understood that the same reference numerals in fig. 8 as in fig. 5 denote the same or similar meanings, and thus, for brevity, will not be described again here. In addition, the communication method shown in fig. 8 does not limit the execution sequence between S530 and S540.

In the communication method shown in fig. 8, the source base station initiates data forwarding of the terminal device after the terminal device accesses the target base station. Compared with the method that the data forwarding of the terminal equipment is initiated to the target base station immediately after the source base station sends the switching command to the terminal equipment, the method has the advantage that the time point of initiating the data forwarding of the terminal equipment to the target base station by the source base station is delayed, so that the waste of transmission resources between the source base station and the target base station can be reduced.

In a scenario where the terminal device is connected to the source base station and the target base station at the same time, when the terminal device completes a random access procedure at the target base station, two sets of protocol stacks may be established, one corresponding to the source base station and the other corresponding to the target base station. For the same data of the terminal equipment, the same data can be sent only through one protocol stack of the two protocol stacks, and also can be sent through the two protocol stacks.

An example of two sets of protocol stacks established on a terminal device is shown in fig. 9. As shown in fig. 9, a protocol stack on the source base station includes a sublayer 1, a sublayer 2, a Radio Link Control (RLC) layer, and a MAC layer; the protocol stack on the target base station comprises a sublayer 2, an RLC layer and an MAC layer; the protocol stack corresponding to the source base station on the terminal equipment is the same as the protocol stack on the source base station, and the protocol stack corresponding to the target base station on the terminal equipment is the same as the protocol stack on the target base station. The sublayer 1 is used for reordering the data packets, distributing SN for the data packets, and discarding duplicate data packets; the sublayer 2 is used for encrypting and decrypting the data packets, unpacking or packaging the data packets, and can also be used for ensuring the integrity of the data packets.

Herein, the sublayer 1 may also be referred to as a Packet Data Convergence Protocol (PDCP) Reordering (Reordering) layer, and the sublayer 2 may also be referred to as a PDCP sublayer (sublayer).

Optionally, the PDCP sublayer 1 may also be deployed in the target base station, and the PDCP sublayer 1 on the terminal device may be regarded as a common part of the two sets of protocol stacks.

Aiming at the scene of establishing two sets of protocol stacks on the terminal equipment, the application also provides a communication method for how the terminal equipment sends uplink data.

In a first possible implementation manner, the terminal device may send uplink data only to the source base station or only to the target base station. This communication method may be referred to as a one-sided transmission mode.

In a second possible implementation manner, the terminal device may send uplink data to the source base station and the target base station. Specifically, a part of uplink data of the terminal device is sent to the source base station, and another part of uplink data is sent to the target base station. This communication method may be referred to as a two-sided transmission mode.

In a third possible implementation manner, the terminal device may send uplink data to the source base station and the target base station, and specifically, the same data is sent to both the source base station and the target base station. This communication method may be referred to as a repeat transmission mode. For example, the terminal device transmits the same PDCP SDU to both the source base station and the target base station.

In some possible implementations, the terminal device determines whether to use the single-side transmission mode, the dual-side transmission mode, or the repeated transmission mode according to the specification of the protocol. In the case where the terminal device determines that the one-sided transmission mode is used according to the specification of the protocol, the terminal device may further determine whether to transmit uplink data to the source base station or to transmit uplink data to the target base station according to the specification of the protocol.

In some possible implementations, the terminal device may receive a second indication from the network-side device, where the second indication is used to instruct the terminal device to use the single-sided transmission mode, the dual-sided transmission mode, or the repeated transmission mode. The second indication is used to indicate the terminal device to use the one-sided transmission mode, and specifically, the second indication may be specifically used to indicate the terminal device to transmit uplink data to the source base station or the target base station. The network side device sending the second indication to the terminal device may be the source base station or the target base station.

In some possible implementations, the terminal device may use a single-sided transmission mode, a dual-sided transmission mode, or a repeated transmission mode according to a signal condition between the source base station and the terminal device or a signal condition between the target base station and the terminal device. When the terminal device determines to use the one-sided transmission mode, specifically, the terminal device determines to transmit uplink data to the source base station or to the target base station.

For example, the terminal device may perform measurement on a downlink signal transmitted by the source base station and a downlink signal transmitted by the target base station. If the Reference Signal Receiving Power (RSRP) of one network device of the source base station and the target base station is higher than the RSRP of the other network device, the terminal device selects the one-sided transmission mode and selects to transmit uplink data to the network device with better RSRP.

Or, if the difference value between the RSRP of one network device in the source base station and the RSRP of the other network device in the target base station is greater than or equal to a preset first threshold, the terminal device selects a one-sided sending mode, and selects to send uplink data to the network device with better RSRP.

For example, if the RSRP of the downlink signal transmitted by the target base station is 2dB higher than the RSRP of the downlink signal transmitted by the source base station, the terminal device selects the one-sided transmission mode and transmits uplink data to the target base station.

Or, if the difference value between the RSRP of one network device of the source base station and the RSRP of the other network device is smaller than a preset second threshold, the terminal device selects the two-sided transmission mode.

For example, if the RSRP of the downlink signal transmitted by the target base station is 2dB lower than the RSRP of the downlink signal transmitted by the source base station, the terminal device selects the two-sided transmission mode.

Or, if the difference value between the RSRP of the downlink signal sent by one network device of the source base station and the RSRP of the downlink signal sent by the other network device is smaller than a preset third threshold, and the RSRPs of the downlink signals sent by the two network devices are both smaller than a preset fourth threshold, the terminal device selects a repeated sending mode to improve the reliability of data transmission.

For example, if the RSRP deviation between the downlink signal sent by the source base station and the downlink signal sent by the target base station is within 2dB, and the RSRP of the downlink signal sent by the source base station and the RSRP of the downlink signal sent by the target base station are both lower than a certain threshold, the terminal device may adopt a repeated sending manner.

Fig. 10 is a schematic configuration diagram of a communication apparatus according to an embodiment of the present application. It should be understood that the communication apparatus 1000 shown in fig. 10 is only an example, and the communication apparatus of the embodiment of the present application may further include other modules or units, or include modules having functions similar to those of the respective modules in fig. 10, or not include all the modules in fig. 10.

The communication apparatus 1000 shown in fig. 10 may include a receiving module 1010 and a transmitting module 1020. The modules included in the communication device 1000 may be implemented by software and/or hardware.

The communication apparatus 1000 may be configured to perform the steps performed by the target base station in the communication method described in fig. 3 or fig. 6.

For example, the receiving module 1010 is configured to: receiving a handover request message from a source base station, and receiving a random access preamble from a terminal device; the sending module 1020 is configured to: sending a first indication to the source base station, wherein the first indication is used for triggering the source base station to send a serial number state transition message to the communication device; the receiving module 1010 is further configured to: receiving the sequence number state transition message from the source base station.

Optionally, the first indication is further used to trigger the source base station to initiate data forwarding of the terminal device to the communication apparatus. Accordingly, the receiving module 1010 is further configured to receive data of the terminal device from the source base station.

Optionally, the receiving module 1010 is specifically configured to: and receiving a switching completion message or a reconfiguration completion message from the terminal equipment. Correspondingly, the sending module 1020 is specifically configured to: and responding to the switching completion message or the reconfiguration completion message, and sending the first indication to the source base station.

Optionally, the sending module 1020 is specifically configured to: transmitting the first indication to the source base station in response to the random access preamble.

Fig. 11 is a schematic configuration diagram of a communication apparatus according to an embodiment of the present application. It should be understood that the communication apparatus 1100 shown in fig. 11 is only an example, and the communication apparatus of the embodiment of the present application may further include other modules or units, or include modules having functions similar to those of the respective modules in fig. 11, or not include all the modules in fig. 11.

The communications apparatus 1100 shown in fig. 11 can include a receiving module 1110 and a transmitting module 1120. The modules included in the communication device 1100 may be implemented by software and/or hardware.

The communication apparatus 1100 may be configured to perform the steps performed by the terminal device in the communication method described in fig. 4 or fig. 7.

For example, the receiving module 1110 is configured to receive a handover command from a source base station; the sending module 1120 is configured to send a random access preamble to the target base station; the sending module 1120 is further configured to send a first indication to the source base station, where the first indication is used to trigger the source base station to send a sequence number state transition message to the target base station.

Optionally, the first indication is further used for triggering the source base station to initiate data forwarding of the communication device to the target base station.

Optionally, the receiving module 1110 is specifically configured to: receiving a random access response message from the target base station device. Correspondingly, the sending module 1120 is specifically configured to: transmitting the first indication to the source base station in response to the random access response message.

Optionally, the receiving module 1110 is specifically configured to: receiving a contention resolution message from the target base station apparatus. Correspondingly, the sending module 1120 is specifically configured to: transmitting the first indication to the source base station in response to the contention resolution message.

Optionally, the receiving module 1110 is specifically configured to: and receiving scheduling information scrambled by using the cell radio network temporary identifier of the terminal equipment from the target base station equipment. Correspondingly, the sending module 1120 is specifically configured to: transmitting the first indication to the source base station in response to the scheduling information.

Optionally, the sending module 1120 is further configured to: sending uplink data to the source base station or the target base station according to the specification of a communication protocol; or sending uplink data to the source base station or the target base station according to a second instruction received from the source base station or the target base station; or determining to send uplink data to the source base station or to the target base station according to the signal quality between the source base station and the communication device or the signal quality between the target base station and the communication device.

Fig. 12 is a schematic configuration diagram of a communication apparatus according to an embodiment of the present application. It should be understood that the communication apparatus 1200 shown in fig. 12 is only an example, and the communication apparatus of the embodiment of the present application may further include other modules or units, or include modules having functions similar to those of the respective modules in fig. 12, or not include all the modules in fig. 12.

The communication apparatus 1200 shown in fig. 12 may include a transmitting module 1210 and a receiving module 1220. The modules included in the communication apparatus 1200 may be implemented by software and/or hardware.

The communication apparatus 1200 may be used for performing the steps performed by the source base station in the communication method described in any one of fig. 2 to 8.

For example, the sending module 1210 is configured to send a handover command to the terminal device; the receiving module 1220 is configured to receive a first indication from the terminal device, the target base station, or a core network element; the sending module 1210 is further configured to: in response to the first indication, sending a sequence number state transition message to the target base station.

Optionally, the sending module 1210 is further configured to: and responding to the first indication, and initiating data forwarding of the terminal equipment to the target base station.

Optionally, the receiving module 1220 is specifically configured to: receiving the first indication from the terminal device, the target base station, or the core network element after the terminal device completes a random access procedure for the target base station.

Optionally, when the communication apparatus 1200 receives the first indication from the terminal device, the first indication is carried in a radio resource control message or a medium access layer control unit, or the first indication is a physical layer dedicated indication.

Optionally, when the communication apparatus 1200 receives the first indication from the core network element, the first indication is an end indicator.

Fig. 13 is a schematic configuration diagram of a communication apparatus according to an embodiment of the present application. It should be understood that the communication apparatus 1300 shown in fig. 13 is only an example, and the communication apparatus of the embodiment of the present application may further include other modules or units, or include modules having functions similar to those of the respective modules in fig. 13, or not include all the modules in fig. 13.

The communications apparatus 1300 shown in fig. 13 can include a receiving module 1310 and a transmitting module 1320. The modules included in the communication device 1300 may be implemented by software and/or hardware.

The communication apparatus 1300 may be configured to perform the steps performed by the core network element in the communication method described in fig. 5 or fig. 8.

For example, the receiving module 1310 is configured to receive a modify bearer request message; the sending module 1320 is configured to send a first indication to the source base station, where the first indication is used to trigger the source base station to send an SN status transfer message to the target base station.

Optionally, the first indication is further used to trigger the source base station to initiate data forwarding of the terminal device to the target base station.

Optionally, the first indication may be an end marker.

Fig. 14 is a schematic configuration diagram of a communication apparatus according to an embodiment of the present application. It should be understood that the communication apparatus 1400 shown in fig. 14 is only an example, and the communication apparatus of the embodiment of the present application may further include other modules or units, or include modules having functions similar to those of the respective modules in fig. 14, or not include all the modules in fig. 14.

The communication device 1400 includes a processor 1410 for executing program instructions. Optionally, the communication device 1400 may also include a memory for storing program instructions for execution by the processor.

In one possible implementation, the processor 1410 executes program instructions to implement the operations implemented by the target base station in the communication method described in fig. 3 or fig. 6.

For example, a processor, executing program instructions, may implement: receiving a handover request message from a source base station; receiving a random access preamble from a terminal device; sending a first indication to the source base station, wherein the first indication is used for triggering the source base station to send a serial number state transition message to the communication device; receiving the sequence number state transition message from the source base station.

Optionally, the first indication is further used to trigger the source base station to initiate data forwarding of the terminal device to the communication apparatus. Wherein the processor further implements: and receiving the data of the terminal equipment from the source base station.

Optionally, the processor is specifically configured to: receiving a handover complete message or a reconfiguration complete message from the terminal device; and responding to the switching completion message or the reconfiguration completion message, and sending the first indication to the source base station.

Optionally, the processor is specifically configured to: transmitting the first indication to the source base station in response to the random access preamble.

Alternatively, the communication device 1400 may be a base station. In this case, the communication device 1400 may further include a receiver and a transmitter. Wherein the receiver may be configured to perform the "receiving" step performed by the target base station in the communication method described in fig. 3 or fig. 6; the transmitter may be used to perform the "transmitting" step performed by the target base station in the communication method described in fig. 3 or fig. 6.

Alternatively, the communication device 1400 may be a chip that can be integrated in a base station. In this case, the communication apparatus 1400 may further include a communication interface, wherein the communication interface is configured to perform the "receiving" step and the "transmitting" step performed by the target base station in the communication method described in fig. 3 or fig. 6.

In another possible implementation, the processor 1410 is configured to execute program instructions to implement the operations implemented by the terminal device in the communication method described in fig. 4 or fig. 7.

For example, a processor, executing program instructions, may implement: receiving a handover command from a source base station; sending a random access lead code to a target base station; and sending a first indication to the source base station, wherein the first indication is used for triggering the source base station to send a serial number state transition message to the target base station.

Optionally, the processor is specifically configured to: receiving a random access response message from the target base station device; transmitting the first indication to the source base station in response to the random access response message.

Optionally, the processor is specifically configured to: receiving a contention resolution message from the target base station apparatus; transmitting the first indication to the source base station in response to the contention resolution message.

Optionally, the processor is specifically configured to: receiving scheduling information scrambled using a cell radio network temporary identity of the terminal device from the target base station device; transmitting the first indication to the source base station in response to the scheduling information.

Optionally, the processor further implements: sending uplink data to the source base station or the target base station according to the specification of a communication protocol; or sending uplink data to the source base station or the target base station according to a second instruction received from the source base station or the target base station; or determining to send uplink data to the source base station or to the target base station according to the signal quality between the source base station and the communication device or the signal quality between the target base station and the communication device.

Alternatively, the communication apparatus 1400 may be a terminal device. In this case, the communication device 1400 may further include a receiver and a transmitter. Wherein the receiver may be configured to perform the "receiving" step performed by the terminal device in the communication method described in fig. 4 or fig. 7; the transmitter may be adapted to perform the "transmitting" step performed by the terminal device in the communication method described in fig. 4 or fig. 7.

Alternatively, the communication apparatus 1400 may be a chip that can be integrated in a terminal device. In this case, the communication apparatus 1400 may further include a communication interface, wherein the communication interface is configured to perform the "receiving" step and the "transmitting" step performed by the terminal device in the communication method described in fig. 4 or fig. 7.

In another possible implementation, the processor 1410 is configured to execute program instructions to implement the operations implemented by the source base station in the communication method described in any one of fig. 3 to fig. 8.

For example, a processor, executing program instructions, may implement: sending a switching command to the terminal equipment; receiving a first indication from the terminal device, a target base station or a core network element; in response to the first indication, sending a sequence number state transition message to the target base station.

Optionally, the processor further implements: and responding to the first indication, and initiating data forwarding of the terminal equipment to the target base station.

Optionally, the processor is specifically configured to: receiving the first indication from the terminal device, the target base station, or the core network element after the terminal device completes a random access procedure for the target base station.

Optionally, when the communication device receives the first indication from the core network element, the first indication is an end indicator.

Alternatively, the communication device 1400 may be a base station. In this case, the communication device 1400 may further include a receiver and a transmitter. Wherein the receiver may be configured to perform the "receiving" step performed by the source base station in the communication method described in any one of fig. 3 to 8; the transmitter may be used to perform the "transmitting" step performed by the source base station in the communication method described in any of fig. 3 to 8.

Alternatively, the communication device 1400 may be a chip that can be integrated in a base station. In this case, the communication apparatus 1400 may further include a communication interface, wherein the communication interface is configured to perform the "receiving" step and the "transmitting" step performed by the source base station in the communication method described in any one of fig. 3 to fig. 8.

In another possible implementation manner, the processor 1410 is configured to execute program instructions to implement the operations implemented by the core network element in the communication method described in fig. 5 or fig. 8.

For example, a processor, executing program instructions, may implement: receiving a request message for modifying the load bearing; and sending a first indication to the source base station, wherein the first indication is used for triggering the source base station to send the SN state transfer message to the target base station.

Optionally, the first indication may be an end marker.

Alternatively, the communication apparatus 1400 may be a core network element, for example, an SGW. In this case, the communication device 1400 may further include a receiver and a transmitter. Wherein the receiver may be configured to perform the "receiving" step performed by the target base station in the communication method described in fig. 5 or fig. 8; the transmitter may be used to perform the "transmitting" step performed by the target base station in the communication method described in fig. 5 or fig. 8.

Alternatively, the communication apparatus 1400 may be a chip that can be integrated in a network element of a core network, for example, may be a chip that can be integrated in an SGW. In this case, the communication apparatus 1400 may further include a communication interface, wherein the communication interface is configured to perform the steps of "receiving" and "transmitting" performed by the target base station in the communication method described in fig. 5 or fig. 8.

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

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

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

It should be understood that the processor in the embodiments of the present application may be a Central Processing Unit (CPU), and the processor may also be other general purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, and the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a read-only memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

It is to be understood that "/" in this application means "or". Wherein "and/or" may include three side-by-side schemes. For example, "a and/or B" may include: a, B, A and B. It is understood that "a or B" in this application may include: a, B, A and B.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

A method of communication, comprising:

the target base station receives a switching request message from the source base station;

the target base station receives a random access lead code from terminal equipment;

the target base station sends a first instruction to the source base station, wherein the first instruction is used for triggering the source base station to send a serial number state transition message to the target base station;

the target base station receives the sequence number state transition message from the source base station.
The communication method according to claim 1, wherein the first indication is further used for triggering the source base station to initiate data forwarding of the terminal device to the target base station;

wherein the communication method further comprises:

and the target base station receives the data of the terminal equipment from the source base station.
The communication method according to claim 1 or 2, wherein the target base station sends a first indication to the source base station, comprising:

the target base station receives a switching completion message or a reconfiguration completion message from the terminal equipment;

and the target base station responds to the switching completion message or the reconfiguration completion message and sends the first indication to the source base station.
The communication method according to claim 1 or 2, wherein the target base station sends a first indication to the source base station, comprising:

the target base station sends the first indication to the source base station in response to the random access preamble.
A method of communication, comprising:

the terminal equipment receives a switching command from a source base station;

the terminal equipment sends a random access lead code to a target base station;

and the terminal equipment sends a first instruction to the source base station, wherein the first instruction is used for triggering the source base station to send a serial number state transition message to the target base station.
The communication method according to claim 5, wherein the first indication is further used for triggering the source base station to initiate data forwarding of the terminal device to the target base station.
The communication method according to claim 5 or 6, wherein the terminal device sends a first indication to the source base station, comprising:

the terminal equipment receives a random access response message from the target base station equipment;

and responding to the random access response message, and sending the first indication to the source base station by the terminal equipment.
The communication method according to claim 5 or 6, wherein the terminal device sends a first indication to the source base station, comprising:

the terminal equipment receives a competition resolving message from the target base station equipment;

and responding to the competition resolving message, and sending the first indication to the source base station by the terminal equipment.
The communication method according to claim 5 or 6, wherein the terminal device sends a first indication to the source base station, comprising:

the terminal equipment receives scheduling information scrambled by using a cell radio network temporary identifier of the terminal equipment from the target base station equipment;

and responding to the scheduling information, and the terminal equipment sends the first indication to the source base station.
The communication method according to any one of claims 5 to 9, characterized in that the communication method further comprises:

the terminal equipment sends uplink data to the source base station or the target base station according to the specification of a communication protocol; or

The terminal equipment receives a second instruction from a source base station or a target base station and sends uplink data to the source base station or the target base station according to the second instruction; or

And the terminal equipment sends uplink data to the source base station or the target base station according to the signal quality between the source base station and the terminal equipment or the signal quality between the target base station and the terminal equipment.
A method of communication, comprising:

the source base station sends a switching command to the terminal equipment;

the source base station receives a first instruction from the terminal equipment, the target base station or a core network element;

in response to the first indication, the source base station sends a sequence number state transition message to the target base station.
The communication method according to claim 11, further comprising:

and responding to the first indication, and initiating data forwarding of the terminal equipment to the target base station by the source base station.
The communication method according to claim 11 or 12, wherein the receiving, by the source base station, the first indication from the terminal device, the target base station, or a core network element comprises:

the source base station receives the first indication from the terminal device, the target base station, or the core network element after the terminal device completes a random access procedure for the target base station.
The communication method according to any of claims 11 to 13, wherein when the source base station receives the first indication from the terminal device, the first indication is carried in a radio resource control message or a media access control element, or the first indication is a physical layer dedicated indication.
The communication method according to any of claims 11 to 13, wherein the first indication is an end indicator when the source base station receives the first indication from the core network element.
A communications apparatus comprising a processor coupled to a memory, the processor configured to execute program instructions to implement:

receiving a handover request message from a source base station;

receiving a random access preamble from a terminal device;

sending a first indication to the source base station, wherein the first indication is used for triggering the source base station to send a serial number state transition message to the communication device;

receiving the sequence number state transition message from the source base station.
The communications apparatus of claim 16, wherein the first indication is further configured to trigger the source base station to initiate data forwarding for the terminal device to the communications apparatus;

wherein the processor further implements: and receiving the data of the terminal equipment from the source base station.
The communication apparatus according to claim 16 or 17, wherein the processor is configured to:

receiving a handover complete message or a reconfiguration complete message from the terminal device;

and responding to the switching completion message or the reconfiguration completion message, and sending the first indication to the source base station.
The communication apparatus according to claim 16 or 17, wherein the processor is configured to: transmitting the first indication to the source base station in response to the random access preamble.
A communications apparatus comprising a processor coupled to a memory, the processor configured to execute program instructions to implement:

receiving a handover command from a source base station;

sending a random access lead code to a target base station;

and sending a first indication to the source base station, wherein the first indication is used for triggering the source base station to send a serial number state transition message to the target base station.
The communications apparatus of claim 20, wherein the first indication is further configured to trigger the source base station to initiate data forwarding for the communications apparatus to the target base station.
The communication device according to claim 20 or 21, wherein the processor is configured to:

receiving a random access response message from the target base station device;

transmitting the first indication to the source base station in response to the random access response message.
The communication device according to claim 20 or 21, wherein the processor is configured to:

receiving a contention resolution message from the target base station apparatus;

transmitting the first indication to the source base station in response to the contention resolution message.
The communication device according to claim 20 or 21, wherein the processor is configured to: receiving scheduling information scrambled using a cell radio network temporary identity of the terminal device from the target base station device;

transmitting the first indication to the source base station in response to the scheduling information.
The communications apparatus of any of claims 20-24, wherein the processor further implements:

sending uplink data to the source base station or the target base station according to the specification of a communication protocol; or

Sending uplink data to the source base station or the target base station according to a second instruction received from the source base station or the target base station; or

And determining to send uplink data to the source base station or the target base station according to the signal quality between the source base station and the communication device or the signal quality between the target base station and the communication device.
A communications apparatus comprising a processor coupled to a memory, the processor configured to execute program instructions to implement:

sending a switching command to the terminal equipment;

receiving a first indication from the terminal device, a target base station or a core network element;

in response to the first indication, sending a sequence number state transition message to the target base station.
The communications apparatus of claim 26, wherein the processor further implements: and responding to the first indication, and initiating data forwarding of the terminal equipment to the target base station.
The communication device according to claim 26 or 27, wherein the processor is configured to: receiving the first indication from the terminal device, the target base station, or the core network element after the terminal device completes a random access procedure for the target base station.
A communications device as claimed in any of claims 26 to 28, wherein the communications device receives the first indication from the core network element, the first indication being an end indicator.
A computer-readable storage medium, in which a program code for a communication apparatus to execute is stored, the program code comprising instructions for executing the communication method according to any one of claims 1 to 15.