CN113556690B

CN113556690B - Communication method and device

Info

Publication number: CN113556690B
Application number: CN202010335293.4A
Authority: CN
Inventors: 谭佳瑶; 李娇娇; 张向东; 常俊仁; 张亮亮
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-04-24
Filing date: 2020-04-24
Publication date: 2022-11-25
Anticipated expiration: 2040-04-24
Also published as: WO2021213305A1; CN113556690A

Abstract

The application provides a communication method and a communication device, wherein a first sequence number of a first MBS data packet which is sent by a first access network device at present is determined to be compared with a second sequence number of a first MBS data packet which is sent by a second access network device at present by the second access network device, and a switching strategy of a terminal device is determined according to a size relation between the first sequence number and the second sequence number. According to the communication method and the communication device, after the second access network device can determine the progress of sending the data packet by the first access network device through the interaction of the serial numbers between the two access network devices, the switching strategy of the terminal device is determined according to the progress of sending the data packet between the first access network device and the second access network device, and then the access network devices can also determine the switching strategy of the terminal device in a multicast communication scene to ensure the service continuity of the terminal device during switching, so that the communication efficiency is improved.

Description

Communication method and device

Technical Field

The present application relates to communications technologies, and in particular, to a communication method and apparatus.

Background

With the continuous development of communication technology, a wireless communication system can provide more different types of downlink data transmission services for terminal devices, wherein a multimedia broadcast multicast service (MBS or MBMS) is a downlink data transmission service that can be provided by a node in the wireless communication system to multiple terminal devices at the same time, and supports two modes of a multimedia broadcast service and a multicast service, so that multimedia video information can be directly broadcast to all users, and also can be sent to a group of subscribers who charge to watch, and an operator can be helped to develop various commercial applications such as multimedia advertisement, free and charged television channels, multimedia message group sending, and the like. MBS services may also be referred to as multicast services or multicast services, etc. MBMS is introduced by the third Generation Partnership project (3 rd Generation Partnership project,3 gpp) for effectively utilizing mobile communication network resources, and provides a point-to-multipoint service in which one data source transmits data to a plurality of users in a mobile communication network, thereby implementing network resource sharing and improving resource utilization, particularly air interface resources.

In the MBS service, when the terminal device is switched from the first base station to the second base station, if the first base station and the second base station both transmit MBS service data in a multicast mode at the same time, however, due to different scheduling of the two base stations, the schedules of the MBS service data transmitted by the two base stations may have a certain deviation. This results in that the terminal device cannot simply reuse Dual Active Protocol Stack (DAPS) handover when performing MBS multicast service. For a terminal device switching from a first base station to a second base station, if MBS service data sent by the first base station lags MBS service data sent by the second base station, data loss of a deviation part between the two base stations may be caused, thereby causing data discontinuity of the MBS service data and reducing user experience of the terminal device.

Therefore, how to determine that the DAPS handover can be used when the terminal device is handed over from the first base station to the second base station in a multicast communication scenario, and how to determine the schedules of sending downlink communication data by the first base station and the second base station when the DAPS handover is performed, so as to ensure the continuity of multicast data received when the terminal device is handed over to the base stations, is a technical problem to be solved in the art.

Disclosure of Invention

The first aspect of the present application provides a communication method, which is applicable to a second access network device to determine a switching policy of a terminal device, where the determined switching policy may avoid service interruption of the terminal device during a switching process, so as to ensure service continuity during switching of the terminal device, and further improve communication efficiency of the terminal device.

Specifically, the method comprises the following steps: the second access network equipment determines a first sequence number of a first MBS data packet to be sent by the first access network equipment currently and a second sequence number of a first MBS data packet to be sent by the second access network equipment currently, and determines a switching strategy of the terminal equipment according to the size relationship between the first sequence number and the second sequence number.

Therefore, in the communication method provided in this embodiment, in the process of switching the terminal device from the first access network device to the second access network device, the second access network device can determine the first sequence number of the first access network device, that is, the progress of sending the data packet by the first access network device, and further can determine the switching policy of the terminal device, thereby overcoming the problem of service discontinuity when the terminal device is switched due to the fact that the data packet sending progress cannot be mutually determined between different access network devices in the existing multicast communication scenario, and improving the communication efficiency of the terminal device by ensuring the service continuity when the terminal device is switched.

In an embodiment of the first aspect of the present application, when the first sequence number is greater than the second sequence number, the second access network device determines that the handover policy of the terminal device is non-DAPS handover (or referred to as conventional handover), and/or when the first sequence number is less than the second sequence number, the second access network device determines that the handover policy of the terminal device is DAPS handover; and/or when the first sequence number is equal to the second sequence number, determining that the switching strategy of the terminal equipment is DAPS switching or non-DAPS switching.

Specifically, in the communication method provided in this embodiment, the second access network device may determine that, according to the fact that the first sequence number is greater than the second sequence number, the progress of sending the MBS data packet by the second access network device is slower, for the same MBS service to which the MBS data packet belongs, the terminal device has received more MBS data packets at the first access network device, and after the terminal device is switched to the second access network device, the situation that the MBS data packet is interrupted and missing does not occur is not generated, so that it is determined that the terminal device can use non-DAPS switching when being switched from the first access network device to the second access network device; and/or the second access network device can determine that the terminal device can use the DAPS handover when switching from the first access network device to the second access network device in the multicast communication scenario in the prior art, thereby ensuring the continuity of multicast service data received by the terminal device, ensuring the communication efficiency of the terminal device, and improving the user experience.

In an embodiment of the first aspect of the present application, after determining a handover policy of a terminal device, a second access network device sends indication information to a first access network device, where the indication information indicates the handover policy determined by the second access network device.

Specifically, in the communication method provided in this embodiment, the indication information may include first indication information and second indication information, where the second access network device further sends the first indication information to the first access network device after determining the conventional handover, and indicates the conventional handover to the first access network device, so that the first access network device and the second access network device perform the conventional handover in a subsequent terminal device handover process; after determining the DAPS handover, the second access network device further sends a DAPS instruction to the first access network device, and instructs the DAPS handover to the first access network device, so that both the first access network device and the second access network device can execute the DAPS handover in a subsequent terminal device handover process.

In an embodiment of the first aspect of the present application, the communication method further includes: receiving the first sequence number from the first access network device; or receiving a first mapping relation and the first sequence number from the first access network device, or receiving the first mapping relation and the first PDCP sequence number from the first access network device. When receiving a first sequence number from a first access network device, a second access network device may directly determine the first sequence number; when receiving the first mapping relationship and the first sequence number from the first access network device, the second access network device may determine the first sequence number, and optionally determine a third mapping relationship according to the first mapping relationship; when receiving the first mapping relationship and the first PDCP sequence number from the first access network device, the second access network device may determine the first sequence number according to the first mapping relationship and the first PDCP sequence number, and optionally determine the third mapping relationship according to the first mapping relationship. The second access network device may determine a sequence number of a data packet sent by the first access network device, compare the sequence number with a sequence number of a data packet sent by the second access network device, and determine a handover policy of the terminal device.

In an embodiment of the first aspect of the present application, when the terminal device performs a DAPS handover, the second access network device sends a third sequence number and/or a third PDCP sequence number to the first access network device. After the second access network device determines to execute the DAPS handover, the second access network device continues to send the data packet until the terminal device actually establishes a connection with the second access network device and can receive data from the second access network device, so that the second access network device sends the third sequence number of the first data packet to be sent to the first access network device after establishing a connection with the terminal device, so that the first access network device sends the data packet before the third sequence number to the terminal device in the DAPS handover process, and the second access network device sends the data packet after the third sequence number to the terminal device in the DAPS handover process, and finally, service continuity when the terminal device is handed over from the first access network device to the second access network device can be achieved.

In an embodiment of the first aspect of the present application, the second access network device receives end indication information sent from the first access network device, and determines that the first access network device has sent a data packet before the third sequence number to the terminal device. Therefore, in this embodiment, the second access network device instructs the terminal device to disconnect from the first access network device, and instructs the first access network device to release the context of the terminal device.

In an embodiment of the first aspect of the present application, the second access network device sends the second mapping relationship to the first access network device; or determining a third mapping relation according to the first mapping relation and the second mapping relation, and sending the third mapping relation to the first access network device.

Specifically, in the embodiment of the present application, based on that two access network devices maintain PDCP sequence numbers respectively and a terminal device can obtain the PDCP sequence numbers of the access network devices through a PDCP layer, in order to maintain continuity of data packets of the two access network devices in an access process, a third mapping relationship may be determined by a first access network device or a second access network device, where the third mapping relationship is used to indicate a corresponding relationship between a PDCP sequence number of a data packet sent by the first access network device and a PDCP sequence number of a data packet sent by the second access network device, and after the first access network device obtains the third mapping relationship, the third mapping relationship is sent to the terminal device.

A second aspect of the present application provides a communication method, which is applicable to a first access network device, where the first access network device sends a first sequence number, or sends the first sequence number and a first mapping relationship, or sends the first PDCP sequence number and the first mapping relationship to a second access network device. And the second access network equipment determines the switching strategy of the terminal equipment according to the first sequence number and the second sequence number. The first access network equipment receives indication information sent by the second access network equipment, wherein the indication information is used for indicating a switching strategy of the terminal equipment.

Specifically, in the communication method provided in this embodiment, the first access network device may determine, by the first sequence number sent to the second access network, or the first sequence number and the first mapping relationship, or the first PDCP sequence number and the first mapping relationship, the second access network device may determine the first sequence number, that is, the progress of sending the data packet by the first access network device, and further may determine a handover policy of the terminal device, and indicate the handover policy to the first access network device, and subsequently the first access network device and the second access network device may execute the determined handover policy. Therefore, the problem of service discontinuity caused by the fact that the sending progress of the data packets cannot be mutually determined among different access network devices in the existing multicast communication scene when the terminal devices are switched is solved, and the communication efficiency of the terminal devices is improved by ensuring the service continuity when the terminal devices are switched.

In an embodiment of the second aspect of the present application, the first access network device receives the second mapping relationship and/or the third mapping relationship sent by the second access network device. The first access network device or the second access network device may determine a third mapping relationship, where the third mapping relationship is used to indicate a corresponding relationship between a PDCP sequence number of a data packet sent by the first access network device and a PDCP sequence number of a data packet sent by the second access network device, and the terminal device may use the PDCP sequence number of the data packet and the third mapping relationship to implement reordering when delivering the data packets in sequence, thereby ensuring in-sequence delivery of the data packets received by the terminal device in the DAPS handover process.

In an embodiment of the second aspect of the present application, after the first access network device receives or determines the third mapping relationship by itself, the third mapping relationship is sent to the terminal device. And when the terminal equipment delivers the data packets in sequence, the reordering can be realized by using the PDCP serial number of the data packets and the third mapping relation, so that the sequential delivery of the data packets received by the terminal equipment in the DAPS switching process is ensured.

In an embodiment of the second aspect of the present application, when the terminal device performs a DAPS handover, the first access network device receives the third sequence number and/or the third PDCP sequence number from the second access network device. After determining to execute the DAPS handover, the second access network device continues to send the data packet until the terminal device establishes a connection with the second access network device and receives data from the second access network device, so that the second access network device sends the third sequence number of the first data packet to be sent to the first access network device after establishing the connection with the terminal device, so that the first access network device sends the data packet before the third sequence number to the terminal device in the DAPS handover process, and finally, service continuity during the handover of the terminal device can be realized.

In an embodiment of the second aspect of the present application, after the first access network device sends the data packet before the third sequence number to the terminal device, the end indication information may be sent to the terminal device and/or the end indication information may be sent to the second access network device. The terminal device can perform in-sequence delivery of the data packets according to the end indication information, and the second access network device can indicate the terminal device to disconnect from the first access network device and indicate the first access network device to release the context of the terminal device.

In an embodiment of the second aspect of the present application, the first access network device may further determine, by means of subscription information of the terminal device, a second access network device switched by the terminal device, where the subscription information is used to indicate multicast service information being received or being interested in being received by the terminal device.

Specifically, in the communication method provided in this embodiment, the first access network device determines the second access network device according to the interest value of the terminal device for the multicast service, so that the multicast service with a higher interest value of the terminal device or the multicast service being received can be provided by the second access network device after being switched, thereby maximally ensuring the continuity of receiving multicast service data during switching of the terminal device, so that the multicast service data is not interrupted during switching due to non-support of the switched second access network device, and further ensuring the communication efficiency of the terminal device.

A third aspect of the present application provides a communication method, which is applicable to a first access network device for determining a handover policy of a terminal device.

Specifically, the method comprises the following steps: the first access network equipment determines a first sequence number of a first MBS data packet to be sent by the first access network equipment currently and a second sequence number of a first MBS data packet to be sent by the second access network equipment currently, and determines a switching strategy of the terminal equipment according to the size relation between the first sequence number and the second sequence number.

Therefore, in the communication method provided in this embodiment, in the process of switching the terminal device from the first access network device to the second access network device, the first access network device can determine the first serial number of the first access network device, that is, the progress of sending the data packet by the first access network device, and can determine the switching policy of the terminal device, thereby overcoming the problem of discontinuous service when the terminal device is switched in the existing multicast communication scenario due to the fact that the sending progress of the data packet cannot be determined mutually between different access network devices, and improving the communication efficiency of the terminal device by ensuring service continuity when the terminal device is switched.

In an embodiment of the third aspect of the present application, when the first sequence number is greater than the second sequence number, the first access network device determines that the handover policy of the terminal device is non-DAPS handover (or referred to as conventional handover), and/or when the first sequence number is less than the second sequence number, the first access network device determines that the handover policy of the terminal device is DAPS handover; and/or when the first sequence number is equal to the second sequence number, determining that the switching strategy of the terminal equipment is DAPS switching or non-DAPS switching.

Specifically, in the communication method provided in this embodiment, the first access network device may determine that, according to the fact that the first sequence number is greater than the second sequence number, the progress of sending the MBS data packet by the second access network device is slower, for the same MBS service to which the MBS data packet belongs, the terminal device has received more MBS data packets at the first access network device, and after the terminal device is switched to the second access network device, the situation that the MBS data packet is interrupted and missing does not occur is not generated, so that it is determined that the terminal device can use non-DAPS switching when being switched from the first access network device to the second access network device; and/or the first access network device can determine that the terminal device can use the DAPS switching when switching from the first access network device to the second access network device in the multicast communication scene in the prior art, and the continuity of multicast service data received by the terminal device is ensured, the communication efficiency of the terminal device is ensured, and the user experience is improved.

In an embodiment of the third aspect of the present application, the communication method further includes: receiving the second sequence number from the second access network device; or receiving a second mapping relationship and the second sequence number from the second access network device, or receiving the second mapping relationship and the second PDCP sequence number from the second access network device. When receiving a second sequence number from a second access network device, the first access network device may directly determine the second sequence number; when receiving the second mapping relationship and the second sequence number from the second access network device, the first access network device may determine the second sequence number, and optionally determine a third mapping relationship according to the second mapping relationship; when receiving the second mapping relationship and the second PDCP sequence number from the second access network device, the first access network device may determine the second sequence number according to the second mapping relationship and the second PDCP sequence number, and optionally determine a third mapping relationship according to the second mapping relationship. The first access network device may determine a sequence number of a data packet sent by the second access network device, and may compare the sequence number with a sequence number of a data packet sent by the first access network device to determine a handover policy of the terminal device.

In an embodiment of the third aspect of the present application, when the terminal device performs a DAPS handover, the first access network device receives a third sequence number and/or a third PDCP sequence number sent from the second access network device. After determining to execute DAPS handover, the second access network device continues to send data packets until the terminal device establishes a connection with the second access network device and receives data from the second access network device, so that the second access network device sends the third sequence number of the first data packet to be sent to the first access network device after establishing a connection with the terminal device, so that the first access network device sends the data packet before the third sequence number to the terminal device in the DAPS handover process, and the second access network device sends the data packet after the third sequence number to the terminal device in the DAPS handover process, thereby finally realizing service continuity when the terminal device is handed over from the first access network device to the second access network device.

In an embodiment of the third aspect of the present application, after the first access network device sends the data packet before the third sequence number to the terminal device, the end indication information may be sent to the terminal device, and/or the end indication information may be sent to the second access network device. The terminal device can deliver the data packets in sequence according to the ending indication information, and the second access network device can indicate the terminal device to disconnect from the first access network device and indicate the first access network device to release the context of the terminal device.

In an embodiment of the third aspect of the present application, after the first access network device receives or determines the third mapping relationship by itself, the third mapping relationship is sent to the terminal device, and the terminal device may implement reordering by using the PDCP sequence number of the data packet and the third mapping relationship when delivering the data packet in sequence, thereby ensuring in-sequence delivery of the data packet received by the terminal device in the DAPS handover process.

In an embodiment of the third aspect of the present application, the first access network device may further determine, by subscription information of the terminal device, a second access network device switched by the terminal device, where the subscription information is used to indicate multicast service information being received or being interested in being received by the terminal device.

A fourth aspect of the present application provides a communication method, which is applicable to a second access network device, where after receiving a handover request of a first access network device, the second access network device sends a second sequence number to the first access network device, or sends the second sequence number and a second mapping relationship, or sends the second PDCP sequence number and the second mapping relationship; the first access network device can determine a handover strategy of the terminal device according to the first sequence number and the second sequence number.

Specifically, in the communication method provided in this embodiment, the second access network device enables the first access network device to determine the second sequence number through the second sequence number sent to the first access network, or through the second sequence number and the second mapping relationship, or through the second PDCP sequence number and the second mapping relationship, so as to implement interaction of the sequence numbers between the two access network devices, and the first access network device can determine the progress of sending a data packet by the first access network device, and further determine the handover policy of the terminal device. Therefore, the problem of service discontinuity caused by the fact that the data packet sending progress cannot be mutually determined between different access network devices in the existing multicast communication scene when the terminal devices are switched is solved, and the communication efficiency of the terminal devices is improved by ensuring the service continuity when the terminal devices are switched.

In an embodiment of the fourth aspect of the present application, when the terminal device performs a DAPS handover, the second access network device sends the third sequence number and/or the third PDCP sequence number to the first access network device. After the second access network device determines to execute the DAPS handover, the second access network device continues to send the data packet until the terminal device establishes a connection with the second access network device and receives data from the second access network device, so that the second access network device sends the third sequence number of the first data packet to be sent to the first access network device after establishing a connection with the terminal device, so that the first access network device sends the data packet before the third sequence number to the terminal device in the DAPS handover process, and the second access network device sends the data packet after the third sequence number to the terminal device in the DAPS handover process, thereby finally realizing service continuity in the handover of the terminal device.

In an embodiment of the fourth aspect of the present application, the second access network device receives end indication information sent by the first access network device, and determines that the first access network device has sent a data packet before the third sequence number to the terminal device. Therefore, in this embodiment, the second access network device can instruct the terminal device to disconnect from the first access network device, and instruct the first access network device to release the context of the terminal device.

A fifth aspect of the present application provides a communication method, which is applicable to a terminal device performing a DAPS handover, where at least one data packet from a first access network device and at least one data packet from a second access network device are received simultaneously, so that in a handover process of the terminal device, a PDCP layer of the terminal device sorts the data packets from the first access network device and the second access network device respectively, delivers the sorted at least one data packet from the first access network device to an upper layer in sequence, and determines that all the data packets of the first access network device have been transmitted through end indication information, and then delivers the at least one data packet from the second access network device to the upper layer in sequence.

In summary, the communication method provided in this embodiment enables the terminal device to use DAPS handover in the process of switching from the first access network to the second access network device, and sequentially submit the data packets from two different access network devices respectively according to the PDCP sequence numbers of the received data packets in the DAPS handover process, thereby ensuring that the terminal device can use DAPS handover when the terminal device is in handover, and in particular, when the progress of sending the data packets by the second access network device is faster and the progress of sending the data packets by the first access network device is slower, ensuring the continuity of MBS service data received by the terminal device, and further improving the communication efficiency of the terminal device.

In an embodiment of the fifth aspect of the present application, before sequentially delivering the data packets sent by the second access network device to the upper layer, the PDCP layer of the terminal device further needs to determine that delivery of the data packets from the first access network device to the upper layer is completed, so as to ensure continuity between the data packets from the two access network devices.

In an embodiment of the fifth aspect of the present application, the terminal device may send subscription information of the terminal to the first access network device, so that the first access network device may determine, through the subscription information of the terminal device, the second access network device to which the terminal device is switched. The subscription information is used for indicating the multicast service information which is being received or is interested to be received by the terminal device. The first access network equipment determines the second access network equipment according to the interest value of the terminal equipment to the multicast service, so that the multicast service with higher interest value of the terminal equipment or the multicast service being received can be provided by the second access network equipment after switching, the continuity of receiving the multicast service data when the terminal equipment is switched is guaranteed to the maximum extent, the multicast service data cannot be interrupted due to the non-support of the switched second access network equipment during switching, and the communication efficiency of the terminal equipment is further guaranteed.

A sixth aspect of the present application provides a communication method, which is applicable to a terminal device using DAPS handover when handing over from a first access network device to a second access network device, where because the terminal device may obtain respective PDCP serial numbers of the first access network device and the second access network device through a PDCP layer, and a third mapping relationship may also represent a corresponding relationship between the PDCP serial numbers of the two access network devices, a data packet sent from the first access network device and a data packet sent from the second access network device may be reordered according to the third mapping relationship, and therefore, in this embodiment, it can be ensured that the terminal device uses DAPS handover when handing over, especially when a progress of sending the data packet by the second access network device is faster and a progress of sending the data packet by the first access network device is slower, and continuity of MBS data received by the terminal device is ensured.

In an embodiment of the sixth aspect of the present application, for an MBS data packet received in a DAPS handover process, the terminal device may map a PDCP sequence number of a data packet of the first access network device to a PDCP sequence number of a data packet of the second access network device according to the third mapping relationship, and perform sorting according to the PDCP sequence number of the second access network device; or, the terminal device may further map the PDCP sequence number of the packet of the second access network device to the PDCP sequence number of the packet of the first access network device according to the third mapping relationship, and perform sorting according to the PDCP sequence number of the first access network device. The terminal equipment can reorder the received data packets, so that the continuity of the data received by the terminal equipment is ensured, and the communication efficiency of the terminal equipment is improved.

In an embodiment of the sixth aspect of the present application, the terminal device may further send subscription information of the terminal to the first access network device, so that the first access network device may determine, through the subscription information of the terminal device, the second access network device switched by the terminal device, where the subscription information is used to indicate multicast service information that the terminal device is receiving or is interested in receiving. The first access network equipment determines the second access network equipment according to the interest value of the terminal equipment for the multicast service, so that the multicast service with higher interest value of the terminal equipment or the multicast service being received can be provided by the second access network equipment after switching, the continuity of receiving the multicast service data during switching of the terminal equipment is guaranteed to the maximum extent, the multicast service data cannot be interrupted due to the non-support of the switched second access network equipment during switching, and the communication efficiency of the terminal equipment is further guaranteed.

A seventh aspect of the present application provides a communication apparatus operable to perform the communication method according to the first aspect of the present application, the apparatus comprising: a processing unit and a communication unit;

the processing unit is used for determining a first serial number and a second serial number; the first sequence number is a sequence number of a first data packet, the first data packet is a first data packet to be sent by first access network equipment, the second sequence number is a sequence number of a second data packet, and the second data packet is a first data packet to be sent by second access network equipment; the processing unit is further configured to determine a handover policy of the terminal device according to the first sequence number and the second sequence number; the first access network device is a source base station of the terminal device, the second access network device is a target base station of the terminal device, and the first sequence number and the second sequence number correspond to a first service.

In an embodiment of the seventh aspect of the present application, the processing unit is specifically configured to determine that the handover policy of the terminal device is a DAPS handover when the first sequence number is smaller than the second sequence number; and/or when the first sequence number is larger than the second sequence number, determining that the switching strategy of the terminal equipment is non-DAPS switching; and/or when the first sequence number is equal to the second sequence number, determining that the switching strategy of the terminal equipment is DAPS switching or non-DAPS switching.

In an embodiment of the seventh aspect of the present application, the communication unit is configured to send, to the first access network device, indication information, where the indication information is used to indicate the handover policy.

In an embodiment of the seventh aspect of the present application, the communication unit is further configured to receive the first sequence number from the first access network device; or receiving a first mapping relation and the first sequence number from the first access network device, where the first mapping relation is used to indicate a correspondence between a sequence number of a data packet sent by the first access network device and a PDCP sequence number of the data packet sent by the first access network device; or, the first mapping relation and the first PDCP sequence number from the first access network device are received, where the first PDCP sequence number is a PDCP sequence number of the first packet.

In an embodiment of the seventh aspect of the present application, the communication unit is further configured to send a third sequence number and/or the third PDCP sequence number to the first access network device, where the third sequence number is a sequence number of a third packet, the third packet is a first packet to be sent by the second access network device, and the third PDCP sequence number is a PDCP sequence number of the third packet.

In an embodiment of the seventh aspect of the present application, the communication unit is further configured to receive end indication information from the first access network device, where the end indication information is used to indicate that the first access network device has completed data transmission to the terminal device.

In an embodiment of the seventh aspect of the present application, the communication unit is further configured to send the second mapping relationship and/or the third mapping relationship to the first access network device; the second mapping relationship is used for indicating a corresponding relationship between a sequence number of a data packet sent by the second access network device and a PDCP sequence number of the data packet sent by the second access network device, and the third mapping relationship is used for indicating a corresponding relationship between a PDCP sequence number of a data packet sent by the first access network device and a PDCP sequence number of a data packet sent by the second access network device.

For technical effects achieved by the communication device described in the seventh aspect of the present application, reference may be made to the communication method according to the first aspect, and details thereof are not repeated.

An eighth aspect of the present application provides a communication apparatus operable to execute the communication method according to the second aspect of the present application, the apparatus comprising: a processing unit and a communication unit;

the communication unit is used for sending a first sequence number to the second access network equipment; or, the first sequence number and the first mapping relation are sent to the second access network device; or, the first PDCP sequence number and the first mapping relationship are sent to the second access network device; the communication unit is further configured to receive indication information from the second access network device, where the indication information is used to indicate a handover policy of a terminal device; the first sequence number is a sequence number of a first data packet, the first data packet is a first data packet to be sent by the first access network device, the first mapping relationship is used for indicating a corresponding relationship between a sequence number of a data packet sent by the first access network device and a PDCP sequence number of the data packet sent by the first access network device, the first PDCP sequence number is a PDCP sequence number of the first data packet, the first access network device is a source base station of the terminal device, the second access network device is a target base station of the terminal device, and the first sequence number corresponds to a first service.

In an embodiment of the eighth aspect of the present application, the communication unit is further configured to receive a second mapping relationship and/or a third mapping relationship sent by the second access network device; the second mapping relationship is used for indicating a corresponding relationship between a sequence number of a data packet sent by the second access network device and a PDCP sequence number of the data packet sent by the second access network device, and the third mapping relationship is used for indicating a corresponding relationship between a PDCP sequence number of a data packet sent by the first access network device and a PDCP sequence number of a data packet sent by the second access network device.

In an embodiment of the eighth aspect of the present application, the communication unit is further configured to send the third mapping relationship to the terminal.

In an embodiment of the eighth aspect of the present application, the communication unit is further configured to receive a third sequence number and/or a third PDCP sequence number from the second access network device, where the third sequence number is a sequence number of a third data packet, the third data packet is a first data packet to be sent by the second access network device, and the third PDCP sequence number is a PDCP sequence number of the third data packet.

In an embodiment of the eighth aspect of the present application, the communication unit is further configured to send end instruction information to the terminal device; and/or sending end indication information to the second access network equipment;

in an embodiment of the eighth aspect of the present application, the processing unit is configured to determine the second access network device according to subscription information from the terminal device, where the subscription information is used to indicate multicast service information that the terminal device is receiving or is interested in receiving.

The technical effects achieved by the communication device according to the eighth aspect of the present application can be achieved by referring to the communication method according to the second aspect, and are not described in detail.

A ninth aspect of the present application provides a communication apparatus operable to execute the communication method according to the third aspect of the present application, the apparatus comprising: a processing unit and a communication unit;

the processing unit is used for determining a first serial number and a second serial number; the first sequence number is a sequence number of a first data packet, the first data packet is a first data packet to be sent by first access network equipment, the second sequence number is a sequence number of a second data packet, and the second data packet is a first data packet to be sent by second access network equipment; the processing unit is further configured to determine a handover policy of a terminal device according to the first sequence number and the second sequence number, where the first access network device is a source base station of the terminal device, the second access network device is a target base station of the terminal device, and the first sequence number and the second sequence number correspond to a first service.

In an embodiment of the ninth aspect of the present application, the processing unit is specifically configured to determine that the handover policy of the terminal device is a DAPS handover when the first sequence number is smaller than the second sequence number; and/or when the first serial number is larger than the second serial number, determining that the switching strategy of the terminal equipment is non-DAPS switching; and/or when the first sequence number is equal to the second sequence number, determining that the switching strategy of the terminal equipment is DAPS switching or non-DAPS switching.

In an embodiment of the ninth aspect of the present application, the communication unit is configured to receive a second sequence number from the second access network device; or receiving a second mapping relation and the second sequence number from the second access network device, where the second mapping relation is used to indicate a correspondence between a sequence number of a data packet sent by the second access network device and a PDCP sequence number of the data packet sent by the second access network device; or, receiving the second mapping relation and the second PDCP sequence number sent by the second access network device, where the second PDCP sequence number is a PDCP sequence number of the second data packet.

In an embodiment of the ninth aspect of the present application, the communication unit is further configured to receive a third sequence number and/or a third PDCP sequence number from the second access network device, where the third sequence number is a sequence number of a third packet, the third packet is a first packet to be sent by the second access network device, and the third PDCP sequence number is a PDCP sequence number of the third packet.

In an embodiment of the ninth aspect of the present application, the communication unit is further configured to send end indication information to the second access network device; and/or sending ending indication information to the terminal equipment;

in an embodiment of the ninth aspect of the present application, the communication unit is further configured to send a third mapping relationship to the terminal device; the third mapping relationship is used for indicating a corresponding relationship between the PDCP sequence number of the data packet sent by the first access network device and the PDCP sequence number of the data packet sent by the second access network device.

In an embodiment of the ninth aspect of the present application, the processing unit is further configured to determine the second access network device according to subscription information of the terminal device, where the subscription information is used to indicate multicast service information that the terminal device is receiving or is interested in receiving.

For technical effects achieved by the communication apparatus according to the ninth aspect of the present application, reference may be made to the communication method according to the third aspect, and details thereof are not repeated.

A tenth aspect of the present application provides a communication apparatus operable to execute the communication method according to the fourth aspect of the present application, the apparatus comprising: a processing unit and a communication unit;

the communication unit is used for receiving a switching request from a first access network device; the communication unit is further configured to send the second sequence number to the first access network device; or, the second sequence number and the second mapping relation are sent to the first access network device; or, sending a second PDCP sequence number and the second mapping relationship to the first access network device; the second sequence number is a sequence number of a second data packet, the second data packet is a first data packet to be sent by the second access network device, the second mapping relationship is used for indicating a corresponding relationship between a sequence number of a data packet sent by the second access network device and a PDCP sequence number of a data packet sent by the second access network device, the second PDCP sequence number is a PDCP sequence number of the second data packet, the first access network device is a source base station of the terminal device, the second access network device is a target base station of the terminal device, and the second sequence number corresponds to the first service.

In an embodiment of the tenth aspect of the present application, the communication unit is further configured to send a third sequence number and/or a third PDCP sequence number to the first access network device, where the third sequence number is a sequence number of a third data packet, the third data packet is a sequence number of a data packet to be sent by the second access network device, and the third PDCP sequence number is a PDCP sequence number of the third data packet.

In an embodiment of the tenth aspect of the present application, the communication unit is further configured to receive end indication information from the first access network device, where the end indication information indicates that the first access network device has completed data transmission to the terminal device.

The technical effects achieved by the communication apparatus described in the tenth aspect of the present application can be achieved by referring to the communication method according to the fourth aspect, and are not described in detail.

An eleventh aspect of the present application provides a communication apparatus operable to execute the communication method according to the fifth aspect of the present application, the apparatus comprising: a processing unit and a communication unit;

the communication unit is configured to receive at least one data packet from a first access network device and at least one data packet from a second access network device; the processing unit is configured to, in order, deliver, by the PDCP layer to an upper layer, at least one packet from the first access network device; the communication unit is further configured to receive end indication information from the first access network device, where the end indication information indicates that the first access network device has completed data transmission to the terminal device; the processing unit is further configured to, in order, deliver at least one data packet from the second access network device to an upper layer by the PDCP layer.

In an embodiment of the eleventh aspect of the present application, the processing unit is further configured to determine that in-order delivery of data packets from the first access network device to an upper layer is completed.

In an embodiment of the eleventh aspect of the present application, the communication unit is further configured to send subscription information of the terminal device to the first access network device, where the subscription information is used to indicate multicast service information that the terminal device is receiving or interested in receiving.

For technical effects achieved by the communication device according to the eleventh aspect of the present application, reference may be made to the communication method according to the fifth aspect, and details thereof are not repeated.

A twelfth aspect of the present application provides a communication apparatus operable to execute the communication method according to the sixth aspect of the present application, the apparatus comprising: a processing unit and a communication unit;

the communication unit is configured to receive a third mapping relationship from the first access network device; the third mapping relation is used for representing the corresponding relation between the PDCP serial number of the first access network equipment and the PDCP serial number of the second access network equipment; the communication unit is configured to reorder, according to the third mapping relationship, the data packet sent from the first access network device and the data packet sent from the second access network device.

In an embodiment of the twelfth aspect of the present application, the processing unit is further configured to map, according to the third mapping relationship, a PDCP sequence number of a packet from the first access network device to a PDCP sequence number of a packet of the second access network device; or mapping the PDCP sequence number of the data packet from the second access network equipment into the PDCP sequence number of the data packet of the first access network equipment according to the third mapping relation;

in an embodiment of the twelfth aspect of the present application, the communication unit is further configured to send subscription information of the terminal device to the first access network device, where the subscription information is used to indicate multicast service information that the terminal device is receiving or is interested in receiving.

The technical effects achieved by the communication device described in the twelfth aspect of the present application can be achieved by referring to the communication method according to the sixth aspect, and are not described again.

In a thirteenth aspect, an embodiment of the present application provides a communication apparatus, including: a processor and a communication interface.

The communication interface is used for realizing the connection communication between the communication device and the peripheral equipment.

The processor is configured to implement the method of the first, second, third, fourth, fifth or sixth aspect.

As a possible design, the communication device further includes: a memory.

The memory is configured to store a computer program, and the processor executes the computer program stored in the memory to cause the apparatus to perform the method of the first, second, third, fourth, fifth, or sixth aspect.

As a possible design, the communication device further includes: a transceiver.

The transceiver is used for transmitting and receiving messages.

In a fourteenth aspect, embodiments of the present application provide a computer-readable storage medium storing a computer program which, when executed, implements a method as described in the first, second, third, fourth, fifth or sixth aspect above.

In a fifteenth aspect, an embodiment of the present application provides a chip, including a processor and a communication interface;

the communication interface is used for realizing communication with other equipment;

the processor is configured to read instructions to implement a method as described in the first, second, third, fourth, fifth or sixth aspect above.

In a sixteenth aspect, embodiments of the present application provide a computer program product comprising computer program code which, when executed by a computer, causes the computer to perform the method of the first, second, third, fourth, fifth or sixth aspect as described above.

A seventeenth aspect of the present invention provides a communication system, where the communication device according to the seventh aspect of the present invention is used as a second access network device, the communication device according to the eighth aspect of the present invention is used as a first access network device, and the communication device according to the eleventh/second aspect of the present invention is used as a terminal device; alternatively, a communication apparatus according to the ninth aspect of the present application is included as a first access network device, a second access network device according to the tenth aspect of the present application, and a communication apparatus according to the eleventh/second aspect of the present application is included as a terminal device.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of a communication system applied in the embodiment of the present application;

FIG. 2 is a schematic diagram of a communication system;

Fig. 3 is a schematic diagram of a terminal device performing handover between base stations in a multicast scenario;

fig. 4 is a schematic flowchart of a terminal device during handover between access network devices;

FIG. 5 is a schematic diagram illustrating the transmission progress of MBS data packets when a terminal device switches base stations;

fig. 6 is a schematic diagram illustrating MBS data progress when another terminal device switches base stations;

fig. 7 is a schematic flowchart of another terminal device during handover between base stations;

fig. 8 is a flowchart illustrating a first embodiment of a communication method provided in the present application;

fig. 9 is a flowchart illustrating a second communication method according to an embodiment of the present application;

fig. 10 is a flowchart illustrating a third embodiment of a communication method provided in the present application;

fig. 11 is a flowchart illustrating a fourth embodiment of a communication method according to the present application;

fig. 12 is a schematic flowchart of a fifth communication method according to an embodiment of the present application;

fig. 13 is a flowchart illustrating a sixth embodiment of a communication method according to the present application;

fig. 14 is a flowchart of a seventh embodiment of a communication method provided in the present application;

fig. 15 is a schematic flowchart of an eighth embodiment of a communication method provided in the present application;

fig. 16 is a flowchart illustrating a ninth communication method according to the present application;

Fig. 17 is a schematic flowchart of a tenth embodiment of a communication method provided in the present application;

fig. 18 is a schematic flowchart of an eleventh embodiment of a communication method provided in the present application;

fig. 19 is a schematic structural diagram of a first embodiment of a communication device provided in the present application;

fig. 20 is a schematic structural diagram of a second communication device according to an embodiment of the present application.

Detailed Description

Fig. 1 is a schematic structural diagram of an embodiment of a communication system applied in the embodiment of the present application, and fig. 1 is a schematic structural diagram of a possible network architecture applicable to the embodiment of the present application, which includes a terminal device 110, an access network device 120, and a core network device 130. Terminal device 110 may be wirelessly connected to access network device 120, and access network device 120 may be connected to core network device 130 in a wired or wireless manner. Core network device 130 and access network device 120 may be separate and distinct physical devices, or core network device 130 and access network device 120 may be the same physical device having all/part of the logical functions of core network device 130 and access network device 120 integrated thereon.

Network device 120 shown in fig. 1 may be an access network device, and terminal device 110 may be fixed or mobile, without limitation. The network architecture shown in fig. 1 may further include other network devices, such as a wireless relay device and a wireless backhaul device, without limitation. In the architecture shown in fig. 1, the number of terminal devices 110, access network devices 120, and core network devices 130 is not limited. The network architecture shown in fig. 1 is merely an illustration, and is not a limitation to the embodiments of the present application. For example, the technical solutions in the embodiments of the present application can be applied to various communication systems. For example, the radio access network (GSM EDGE radio access network) architecture of a 5th generation (5 g) communication system, a Long Term Evolution (LTE) communication system, a Universal Mobile Telecommunications System (UMTS) terrestrial radio access network (UTRAN) system, or a global system for mobile communications (GSM)/enhanced data rates for GSM evolution (EDGE) system. In addition, the technical solution shown in the present application may also be applied to other communication systems, for example: public Land Mobile Network (PLMN).

The access network device 120 shown in fig. 1 may also be referred to as a Radio Access Network (RAN) device, and is a device for providing a terminal device with a wireless communication function. Access network equipment includes, for example but is not limited to: the present invention relates to a new radio access technology (NR) base station (G nodeB, gNB), and may also be a Long Term Evolution (LTE) base station (evolved nodeB, eNB), and may also be a base station (nodeB, NB) in a WCDMA system, a base station (BTS) in a GSM system or a CDMA system, and the network device may also be a relay station, an access point, a vehicle-mounted device, a wearable device, and a network-side device in a network after 5G or a network device in a future evolved Public Land Mobile Network (PLMN), a roadside unit (RSU), and the like.

In the embodiments of the present application, the apparatus for implementing the function of the network device may be a network device; or may be a device, such as a system-on-chip, capable of supporting the network device to implement the function, and the device may be installed in the network device. In the technical solution provided in the embodiment of the present application, a device for implementing a function of a network device is a network device, and the network device is a base station, which is taken as an example, to describe the technical solution provided in the embodiment of the present application.

The terminal device shown in fig. 1 may be referred to as a terminal for short, and is a device with a wireless transceiving function, and the terminal device may be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; can also be deployed on the water surface (such as a ship and the like); and may also be deployed in the air (e.g., airplanes, drones, balloons, satellites, etc.). The terminal device may be a mobile phone (mobile phone), a tablet computer (pad), a computer with a wireless transceiving function, a Virtual Reality (VR) terminal device, an Augmented Reality (AR) terminal device, a wireless terminal device in industrial control (industrial control), a wireless terminal device in self driving (self driving), a wireless terminal device in remote medical (remote medical), a wireless terminal device in smart grid (smart grid), a wireless terminal device in transportation safety (transportation safety), a wireless terminal device in smart city (smart city), a wireless terminal device in smart home (smart home), and may further include a User Equipment (UE), and the like. The terminal device 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 capability, a computing device or other processing device connected to a wireless modem, a vehicle mounted device, a wearable device, a terminal device in a fifth generation (the 5 g) network in the future or a terminal device in a Public Land Mobile Network (PLMN) in the future, etc. A terminal device may also be sometimes referred to as a terminal device, user Equipment (UE), access terminal device, in-vehicle terminal device, industrial control terminal device, UE unit, UE station, mobile station, remote terminal device, mobile device, UE terminal device, wireless communication device, UE agent, or UE device, etc. The terminal equipment may also be fixed or mobile. The embodiments of the present application do not limit this.

In the embodiment of the present application, the apparatus for implementing the function of the terminal may be a terminal device; it may also be an apparatus, such as a system-on-chip, capable of supporting the terminal device to implement the function, and the apparatus may be installed in the terminal device. In the embodiment of the present application, the chip system may be composed of a chip, and may also include a chip and other discrete devices. In the technical solution provided in the embodiment of the present application, the apparatus for implementing the function of the terminal device is the terminal device, and the terminal device may be UE as an example, so as to describe the technical solution provided in the embodiment of the present application.

Exemplarily, fig. 2 is a schematic diagram of a communication system, in which when the communication system shown in fig. 1 is a 5G NR communication system, an access network device NG-RAN may be a base station gNB/NG-eNB of a serving cell accessed by a terminal device, and the access network device may provide a user plane and a control plane protocol function of a 5G radio access network NR for the terminal device; the core network device may include an access and mobility management function (AMF) entity, a User Plane Function (UPF) entity, and the like, where the AMF may be used to implement functions of registration management, mobility management, access authorization, and the UPF may be used to implement functions of packet routing and forwarding, quality of service (QoS) processing on a user plane, and the like. In the communication system shown in fig. 2, xn messages are sent between one base station gNB/NG-eNB and another base station gNB/NG-eNB through Xn interfaces, the two base stations respectively complete corresponding operations according to the indication/content of the Xn messages, and the two base stations are connected to a 5G core network (5G core, 5gc) through NG interfaces.

More specifically, in the communication system shown in fig. 1, the downlink communication data transmitted by access network device 120 to terminal device 110 includes: unicast (unicast), broadcast (broadcast), multicast (multicast), and the like, wherein unicast refers to single-point-to-single-point communication between network equipment and terminal equipment in a one-to-one manner, the network equipment sends downlink communication data to the terminal equipment respectively, and for some repeated data network equipment, the network equipment needs to repeatedly send the downlink communication data to different terminal equipment for multiple times, so that the communication load between the network equipment and the terminal equipment is increased; when the network device sends the downlink communication data in a broadcast manner, all terminal devices within the coverage area of the network device, even terminal devices not requiring the data, may receive the downlink communication data of other terminal devices, thereby wasting valuable communication resources between the network device and the terminal devices. Therefore, multicast is a communication method for overcoming the above mentioned disadvantages of unicast and broadcast, and may also be called as multicast or multicast, when a network device sends the same downlink transmission data to a plurality of different terminal devices, the network device may purposefully send the downlink transmission data to the terminal device to be received through the address information of the plurality of terminal devices, and is a method for performing downlink communication data transmission between one network device and a plurality of terminal devices, and common multicast services include mobile phone television services and the like. For example, in the communication system shown in fig. 1, the access network device 120 may send the same data to the two terminal devices 110 in a multicast manner, and then the access network device 120 only needs to send downlink communication data once, and the two terminal devices 110 may receive the same downlink communication data.

Meanwhile, in the communication system shown in fig. 1 and 2, it is a common communication scenario that the terminal device performs handover between different base stations due to its mobility, for example, fig. 3 is a schematic diagram of the terminal device performing handover between base stations in a multicast scenario, where a core network device may provide data of the same multimedia broadcast multicast service (multimedia broadcast multicast service) service to a first access network device and a second access network device, and the first access network device and the second access network device may each multicast and send the received data of the same MBS service to respective groups of terminal devices in the form of MBS data packets. As shown in fig. 3, the first access network device sends MBS data packets of an MBS service to three terminal devices, namely UE0, UE1 and UE2, in a multicast manner, and the second access network device sends MBS data packets of an MBS service to UE3 and UE4 in a multicast manner. Then UE2 may switch from accessing the first access network device to accessing the second access network device when moving from the coverage of the first access network device to the coverage of the second access network device, and UE2 may also continue to receive the multicast MBS data packets from the second access network device after the switch.

Fig. 4 is a schematic flowchart of a process when a terminal device switches between access network devices, and the process of switching the terminal device from a first access network device to a second access network device shown in fig. 4 may be applied to the scenario shown in fig. 3. Specifically, the first access network device refers to a base station to which the terminal device is currently accessed, the second access network device is a base station to which the terminal device is to be switched and accessed, and the first access network device may determine, through information such as a measurement report of the terminal device, whether the terminal device performs switching and determine the second access network device to which the terminal device performs switching. Then, after the first access network device determines that the terminal device is switched to the second access network device, a switching request message is sent to the second access network device through S401, where the switching request message further includes relevant information for the second access network device to determine the switching of the terminal device. After receiving the handover request message, the second access network device performs admission control on the terminal device in S402, and returns a handover request acknowledgement message to the first access network device through S403. After the first access network device receives the handover request acknowledgement message of the second access network device, an RRCReconfiguration message may be sent to the terminal device in S404 to trigger the terminal device to perform the handover of the Uu interface, where the RRCReconfiguration message includes related information for the terminal device to handover to the second access network device. Subsequently, the terminal device completes the RRC connection handover procedure from the first access network device to the second access network device S405, and sends an rrcreeconfiguration complete message to the second access network device S406 to confirm that the handover is successful. The second access network device sends a PATH SWITCH REQUEST (PATH SWITCH REQUEST) message to the AMF entity through S407, triggering 5GC side to SWITCH the DL data PATH of the terminal device to the second access network device, and establishing an NG-C interface instance towards the second access network device. In S408, the 5GC switches the DL data path of the terminal device to the second access network device, and the UPF sends one or more "end marker" packets to the first access network device on the old path per PDU session/tunnel, and may then release any user plane/TNL resources to the first access network device. After completing the PATH switching, the AMF confirms the PATH switching REQUEST to the second access network device using a PATH SWITCH REQUEST ACKNOWLEDGE message PATH SWITCH REQUEST ACKNOWLEDGE in S409. Finally, the second access network device informs the first access network device that the terminal device has been successfully switched through the UE Context Release message in S410, and the first access network device releases the resource related to the terminal device, thereby completing all the procedures for switching the terminal device from the first access network device to the second access network device.

In the terminal device switching process shown in fig. 4, the first access network device may stop sending downlink communication data to the terminal device during the terminal device switching process from the first access network device to the second access network device, and the second access network device may start to continue multicast sending downlink communication data to the terminal device instead of the terminal device after the terminal device is accessed. Therefore, from the perspective of the terminal device, the downlink communication data sent by the first access network device is received before the handover, the downlink communication data sent by the second access network device is received after the handover, and if the terminal device is still receiving the downlink communication data when the terminal device is handing over the base station, the continuity of the data needs to be maintained before and after the handover, so as to prevent the data loss caused by data interruption. For example, in a communication scenario such as unicast, the first base station ensures the continuity of the downlink communication data received by the terminal device by forwarding the buffered unicast data to the second base station.

However, in a multicast communication scenario, the core network may send the same MBS service data to the first access network device and the second access network device at the same time, but when the scheduling of the service data of the first access network device and the service data of the second access network device are different, the schedules of actually sent MBS data packets may differ when the first access network device and the second access network device process the same MBS service sent by the core network. For example, fig. 5 is a schematic diagram of a sending progress of MBS data packets when a terminal device switches a base station, where it is assumed that a UPF entity on a core network side splits MBS service data to be sent into a plurality of MBS data packets, and sends MBS data packets marked with Serial Numbers (SNs) to a first access network device and a second access network device at the same time, and the first access network device and the second access network device multicast the received MBS data packets respectively. Because the first access network device and the second access network device schedule the MBS data packets differently, at the time shown in fig. 5, the first access network device sends the MBS data packets with sequence numbers 15 to 18 to the terminal device, and the second access network device sends the MBS data packets with sequence numbers 30 to 33 to the terminal device. Suppose that before the terminal device switches from the first access network device to the second access network device, the MBS data packets with sequence numbers 15-18 sent by the first access network device have been received, but after the terminal device switches to the second access network device, the second access network device is multicasting the MBS data packets with sequence numbers 30-33, which results in that the sequence numbers of the MBS data packets received by the terminal device before and after the switching are 15-18,30-33, and MBS data packets with sequence numbers 19-29 are lacked, which further results in that the MBS data packets received by the terminal device in the process of switching from the first access network device to the second access network device are discontinuous, and the terminal device finally cannot receive complete MBS service data, which greatly affects the communication efficiency and user experience of the terminal device.

In other embodiments, fig. 6 is a schematic diagram of a progress of MBS data when another terminal device switches a base station, for a multicast communication scenario, after the terminal device switches from a first access network device to a second access network device, if the current schedules of MBS data packets sent by the first access network device and the second access network device are different, for example, before the terminal device switches from the first access network device to the second access network device, an MBS data packet with a sequence number of 15-18 sent by the first access network device is received, but after the terminal device switches to the second access network device, the second access network device is multicasting the MBS data packet with a sequence number of 30-33, the first access network device may send an MBS data packet with a sequence number of 18-29 disconnected in the middle to the second access network device, and the second access network device sends the MBS data packet to the terminal device separately in a unicast manner, so that the MBS data packet received by the terminal device is not interrupted and discontinuous. However, this method increases the link load between the first access network device and the second access network device, and reduces the overall communication efficiency of the communication system.

In addition, in some unicast communication scenarios, a method is further included in which the terminal device can simultaneously receive data sent by the first access network device and the second access network device when switching the base station, and the method may also be referred to as a Dual Active Protocol Stack (DAPS) policy. For example, fig. 7 is a schematic flowchart of another process performed when a terminal device is handed over between base stations, where the method shown in fig. 7 may be used in the communication system shown in fig. 1 or 2, and in the method shown in fig. 7, a first access network device also determines that the terminal device is handed over to a second access network device, and sends a handover request message to the second access network device through S701, where the handover request message further includes related information for the second access network device to determine handover of the terminal device. After receiving the handover request message, the second access network device performs admission control on the terminal device in S702, and returns a handover request acknowledgement message to the first access network device through S703. Specifically, in fig. 7, after the first access network device receives the handover request acknowledgement information of the second access network device, in S704, the rrcreeconfiguration message is sent to the terminal device to trigger the terminal device to perform the handover of the Uu interface, and the rrcreeconfiguration message includes, in addition to the related information for the terminal device to handover to the second access network device, a DAPS indication instructing the terminal device to perform a DAPS handover. Subsequently, according to the DAPS indication received in S704, the terminal device completes an RRC connection handover procedure for handover from the first access network device to the second access network device in S705, and in the handover procedure, the terminal device continues to perform data transmission with the first access network device, for example, receive downlink communication data sent by the first access network device and send uplink communication data to the first access network device. After the terminal device completes the handover from the first access network device to the second access network device, it sends rrcreconfigurecomplete message to the second access network device through S706 to confirm that the handover is successful. Subsequently, the second access network device also sends a handover SUCCESS message HO SUCCESS to the first access network device via S707, notifying the first access network device that the terminal device has accessed the second access network device. As the first access network device, until the handover success message is received in S707, data transmission with the terminal device is stopped, and an SN STATUS TRANSFER message is sent to the second access network device through S708, the terminal device is instructed about a sequence number of data that is sent to the terminal device by the first access network device last, and data that is not received and has not been retransmitted by the terminal device, so that the subsequent second access network device continues to send the data that is not sent and has not been retransmitted by the first access network device to the terminal device. The second access network device further sends a PATH SWITCH REQUEST (PATH SWITCH REQUEST) message to the AMF entity through S709, triggering 5GC side to SWITCH the DL data PATH of the terminal device to the second access network device, and establishing an NG-C interface instance towards the second access network device. In S710, the 5GC switches the DL data path of the terminal device to the second access network device, and the UPF sends one or more "end marker" packets to the first access network device on the old path per PDU session/tunnel, and may then release any user plane/TNL resources to the first access network device. After completing the PATH switching, the AMF ACKNOWLEDGEs the PATH switching REQUEST to the second access network device in S711 by using a PATH switching REQUEST acknowledgement message PATH SWITCH REQUEST ACKNOWLEDGE. Finally, the second access network device notifies the first access network device that the terminal device has been successfully switched through the UE Context Release message in S712, and the first access network device releases the resource related to the terminal device, thereby completing the entire process of switching the terminal device from the first access network device to the second access network device.

It can be seen that, during the above DAPS handover of the terminal device to the base station as shown in fig. 7, during the handover of the terminal device from the first access network device to the second access network device, before the first access network device receives the handover success message and determines that the terminal device has established a connection with the second access network device, the terminal device may simultaneously maintain the connection relationship with the two base stations of the first access network device and the second access network device, and may simultaneously communicate with the two base stations. The first access network equipment stops data transmission with the terminal equipment only after receiving the switching success message, and sends the currently transmitted data packet to the second access network equipment, and the second access network equipment takes over the first access network equipment to continue sending downlink communication data to the terminal equipment, so that the communication carried out by the terminal equipment in the process of switching the base station is not interrupted.

However, the above DAPS handover scenario shown in fig. 7 can only be used in a unicast scenario, and based on that the core network sends downlink communication data to the first access network device for transmission to the terminal device before handover, and sends downlink communication data to the second access network device for transmission to the terminal device after handover, thereby ensuring the continuity of the downlink communication data. However, in a multicast communication scenario, a core network may have sent the same MBS service data to a first access network device and a second access network device, the actual schedules of MBS data packets sent by a terminal device before and after switching when the first access network device and the second access network device send the same MBS service data respectively are different, the first access network device and the second access network device cannot determine the schedule of the MBS data packet sent by the other party, and even if the terminal device maintains a connection relationship with two base stations in a switching process, the two base stations cannot adjust and synchronize the MBS data packets to be sent, so that the terminal device cannot achieve the purpose of DAPS switching in the multicast scenario.

Therefore, how to enable the terminal device to use a DAPS handover strategy when switching from the first access network device to the second access network device in a multicast communication scenario, and the first access network device and the second access network device can synchronously send the progress of downlink communication data when performing DAPS handover, thereby ensuring the continuity of multicast data received by the terminal device when switching the base station, is a technical problem to be solved in the art.

The technical solution of the present application will be described in detail below with specific examples. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments.

Fig. 8 is a flowchart of a first embodiment of a communication method provided by the present application, and the communication method shown in fig. 8 may be applied to a scenario in which the terminal device switches from the first access network device to the second access network device as shown in fig. 3, where the second access network device compares a first sequence number of a first packet to be currently sent by the first access network device with a second sequence number of a first packet to be currently sent by the second access network device, and then determines a switching policy of the terminal device according to sizes of the first sequence number and the second sequence number. Specifically, the communication method provided by the present embodiment includes:

S801: the first access network device sends the first sequence number, or the first sequence number and the first mapping relation, or the first PDCP sequence number and the first mapping relation, to the second access network device.

In this step, in order to enable the second access network device to compare data packets sent by the first access network device and the second access network device, the first access network device sends a first sequence number to the second access network device, or sends information that can be used to indicate the first sequence number, for example, the first access network device may directly send the first sequence number to the second access network device in S801, where the first sequence number is a sequence number of a first data packet, and the first data packet is a first data packet to be sent by the first access network device; or, the first access network device may send, in S801, a first sequence number and a first mapping relationship to the second access network device, where the first mapping relationship is used to indicate a correspondence between a sequence number of a data packet sent by the first access network device and a PDCP sequence number of the data packet sent by the first access network device; still alternatively, the first access network device may send a first PDCP sequence number and the first mapping relationship to the second access network device in S801, where the first PDCP sequence number is a PDCP sequence number of the first packet, and the first sequence number may be obtained by combining the first PDCP sequence number and the first mapping relationship. That is to say, in step S801, the first access network device sends first information to the second access network device, where the first information is used to indicate a first sequence number, and specifically, the first information may include the first sequence number, or the first sequence number and a first mapping relationship, or the first PDCP sequence number and the first mapping relationship.

S802: the second access network device determines a first sequence number and a second sequence number.

Specifically, the second access network device may determine the first sequence number according to the information sent by the first access network device in S801. The second access network device may also determine a second sequence number, where the second sequence number is a sequence number of a second data packet, and the second data packet is a first data packet to be sent by the second access network device. It can be understood that the second access network device determines the current data packet transmission schedule and determines the transmission schedule of the first access network device through the information from the first access network device.

S803: and the second access network equipment determines the switching strategy of the terminal equipment according to the first sequence number and the second sequence number.

Specifically, after determining the first sequence number and the second sequence number, the second access network device may compare the two sequence numbers and determine the handover policy of the terminal device.

Optionally, the handover policy at least includes: DAPS handover and non-DAPS handover. When the first serial number is smaller than the second serial number, the second access network equipment determines that the switching strategy of the terminal equipment is DAPS switching; because the progress of sending the data packet by the second access network equipment is faster, the condition that partial data packet is interrupted and lost can occur after the terminal equipment is directly switched from the first access network equipment with slower sending progress to the second access network equipment, and therefore DAPS switching can be used when the terminal equipment is switched from the first access network equipment to the second access network equipment;

And/or when the first serial number is larger than the second serial number, the second access network equipment determines that the switching strategy of the terminal equipment is non-DAPS switching; because the progress of sending the data packet by the second access network device is slower, for the same service data to which the data packet belongs, the terminal device has already received more data packets at the first access network device, and the situation that the data packet is interrupted and missing cannot occur after the terminal device is switched to the second access network device, so that it is determined that the terminal device can use non-DAPS switching when being switched from the first access network device to the second access network device.

And/or when the first sequence number is equal to the second sequence number, the second access network equipment determines that the switching strategy of the terminal equipment is DAPS switching or non-DAPS switching. The first access network device and the second access network device send the same data packets, so that the data packets that the terminal device can receive before and after the handover are the same, and the second access network device can determine that the terminal device can use non-DAPS handover when the terminal device is handed over from the first access network device to the second access network device; if the second access network device determines that the first sequence number is the same as the second sequence number, but in a subsequent handover process, in a process that the terminal device establishes a connection with the second access network device, a data portion sent by the first access network device may lag behind a data packet sent by the second access network device, and at this time, the second access network device may determine that the DAPS handover may be used when the terminal device is handed over from the first access network device to the second access network device.

Optionally, after determining the handover policy of the terminal device, the second access network device may start to execute the handover policy.

Specifically, in S803, based on that the second access network device can determine that the progress of sending the MBS data packet by the second access network device is slower when the first sequence number is greater than the second sequence number, for the same MBS service to which the MBS data packet belongs, the terminal device has received more MBS data packets in the first access network device, and no MBS data packet interruption or deletion occurs after the terminal device is switched to the second access network device, so as to determine that the terminal device can use non-DAPS switching when being switched from the first access network device to the second access network device; and/or the second access network device can determine that the terminal device can use the DAPS handover when switching from the first access network device to the second access network device in the multicast communication scenario in the prior art, thereby ensuring the continuity of multicast service data received by the terminal device, ensuring the communication efficiency of the terminal device, and improving the user experience.

S804: and the second access network equipment sends indication information to the first access network equipment, wherein the indication information is used for indicating the switching strategy of the terminal equipment. Correspondingly, the first access network device receives the indication information from the second access network device, and determines the switching strategy of the terminal device according to the indication information.

Specifically, after determining the handover policy of the terminal device, the second access network device sends indication information to the first access network device, where the indication information is used to indicate the handover policy, so that the first access network device may also start to execute the handover policy after determining the handover policy according to the indication information.

In summary, in the communication method provided in this embodiment, in the process of switching the terminal device from the first access network device to the second access network device, the second access network device can determine the first serial number of the first access network device, so as to implement the interaction of the serial numbers between the two access network devices, and finally enable the second access network device to determine the progress of sending the data packet by the first access network device, and further enable the progress of sending the data packet between the first access network device and the second access network device to determine the switching policy of the terminal device.

Fig. 9 is a flowchart of a second embodiment of the communication method provided by the present application, and the communication method shown in fig. 9 may be applied to a scenario in which the terminal device switches from the first access network device to the second access network device as shown in fig. 3, where the first access network device compares a first sequence number of a first MBS data packet that is to be currently sent by the first access network device with a second sequence number of a first MBS data packet that is to be currently sent by the second access network device, and then determines a handover policy of the terminal device according to sizes of the first sequence number and the second sequence number. Specifically, the communication method provided by the present embodiment includes:

s901: and the first access network equipment sends the second sequence number to the second access network equipment, or the second sequence number and a second mapping relation, or the second PDCP sequence number and the second mapping relation.

In this step, in order to enable the first access network device to compare data packets sent by the first access network device and the second access network device, the second access network device sends a second sequence number to the first access network device, or information that can be used to indicate the second sequence number, for example, the second access network device may directly send the second sequence number to the first access network device in S901, where the second sequence number is a sequence number of a second data packet, and the second data packet is a first data packet to be sent by the second access network device; or, in S901, the second access network device may send a second sequence number and a second mapping relationship to the first access network device, where the second mapping relationship is used to indicate a correspondence between a sequence number of a data packet sent by the second access network device and a PDCP sequence number of the data packet sent by the second access network device; or, in S901, the second access network device may send a second PDCP sequence number and a second mapping relationship to the first access network device, where the second PDCP sequence number is a PDCP sequence number of the second packet, and the second sequence number may be obtained by combining the second PDCP sequence number and the second mapping relationship.

S902: the first access network device determines a first sequence number and a second sequence number.

Subsequently, the first access network device determines the first sequence number and the second sequence number, where the first access network device may determine the second sequence number according to the information sent by the second access network device in S901. The first access network device may further determine a second sequence number, where the first sequence number is a sequence number of a first data packet, and the first data packet is a first data packet to be sent by the first access network device.

S903: and the first access network equipment determines a switching strategy of the terminal equipment according to the first sequence number and the second sequence number.

Specifically, after determining the first sequence number and the second sequence number, the first access network device may compare the two sequence numbers, and determine a handover policy of the terminal device according to a comparison result.

Optionally, the handover policy at least includes: DAPS handover and non-DAPS handover. When the first sequence number is smaller than the second sequence number, the first access network equipment determines that the switching strategy of the terminal equipment is DAPS switching; when the first sequence number is larger than the second sequence number, the first access network equipment determines that the switching strategy of the terminal equipment is non-DAPS switching; and/or when the first sequence number is equal to the second sequence number, the first access network equipment determines that the switching strategy of the terminal equipment is DAPS switching or non-DAPS switching.

Optionally, after determining the handover policy of the terminal device, the first access network device may start to execute the handover policy.

In summary, in the communication method provided in this embodiment, in the process of switching the terminal device from the first access network device to the second access network device, the first access network device can determine the first serial number of the first access network device, so as to implement the interaction of the serial numbers between the two access network devices, and finally enable the first access network device to determine the progress of sending the data packet by the first access network device, and further enable the progress of sending the data packet between the first access network device and the second access network device to determine the switching policy of the terminal device.

Fig. 10 is a flowchart of a third embodiment of a communication method provided by the present application, where the communication method shown in fig. 10 may be applied to a scenario in which a terminal device is handed over from a first access network device to a second access network device, as shown in fig. 3, and when the terminal device performs DAPS handover, the first access network device and the second access network device perform operations. Specifically, the method comprises the following steps:

s1001: the second access network device sends the third sequence number, and/or the third PDCP sequence number, to the first access network device.

Specifically, when the terminal device establishes a connection with the second access network device in the process of performing the DAPS handover, the second access network device may send the third sequence number and/or the third PDCP sequence number to the first access network device, so as to indicate, to the first access network device, the sequence number of the data packet that will be sent by the second access network device currently.

S1002: and the first access network equipment sends the third sequence number or a data packet before the third PDCP sequence number to the terminal equipment.

Specifically, the terminal device does not immediately disconnect from the first access network device during the DAPS handover, but may continue to receive data packets from the first access network device during the handover. Meanwhile, since the progress of the data packet sent by the first access network device lags behind the second access network device, the first access network device may send the lagging part of the data packet, i.e., the data packet before the third sequence number or the third PDCP sequence number, to the terminal device at this time.

S1003: and the second access network equipment sends the third sequence number or the data packet after the third PDCP sequence number to the terminal equipment.

Specifically, after the terminal device accesses the second access network device, the second access network device may continue to send the third sequence number or the data packet after the third PDCP sequence number to the terminal device.

It should be noted that, the sequence of S1002 and S1003 is not distinguished during the execution, and for the terminal device, the data packet before the third sequence number or the third PDCP sequence number sent by the first access network device may be received at the same time, and the data packet after the third sequence number or the third PDCP sequence number sent by the second access network device may be received.

S1004: and the first access network equipment sends the ending indication information to the second access network equipment.

After the first access network device sends the third sequence number or the data packet before the third PDCP sequence number to the terminal device, the first access network device may send end indication information to the second access network device, where the end indication information is used to indicate that the first access network device has completed data transmission to the terminal device, that is, the data packet before the third sequence number or the third PDCP sequence number has been sent to the terminal device, so that the second access network device can continue subsequent operations, for example, instruct the terminal device to disconnect from the first access network device.

In summary, in this embodiment, in a DAPS handover process from a first access network device to a second access network device, after a second access network device establishes a connection with the terminal device, the second access network device sends a third sequence number and/or a third PDCP sequence number to the first access network device, so that the first access network device can maintain the connection with the terminal device in the DAPS handover process and continue to send a data packet before the third sequence number and/or the third PDCP sequence number to the terminal device, meanwhile, after establishing the connection with the terminal device, the second access network device may continue to send the data packet after the third sequence number and/or the third PDCP sequence number to the terminal device, and finally, after completing data transmission, the first access network device sends an end instruction to the second access network device, so that the second access network device instructs the terminal device to disconnect from the first access network device, and finally complete the entire handover process. In the process, even if the progress of sending the data packet by the first access network device lags behind the data packet sent by the second access network device, the terminal device can continue to receive the lagged part of the data packet from the first access network device and receive the data packet from the second access network device in the DAPS handover process, so that the data packet received by the terminal device is not disconnected in the handover process, the continuity of the received data packet is maintained, and the communication efficiency of the terminal device is finally improved.

In the following, taking an example that a data packet received in a process of switching from a first access network device to a second access network device in a multicast communication scenario by a terminal device is an MBS data packet, a specific implementation of the present application is described.

Fig. 11 is a flowchart of a third embodiment of the communication method provided by the present application, and the communication method shown in fig. 11 may be applied to a scenario in which the terminal device shown in fig. 3 is switched from the first access network device to the second access network device. More specifically, the communication method provided in this embodiment includes:

a first part: in the process that the terminal device is switched from the first access network device to the second access network device, the second access network device compares a first sequence number of a first MBS data packet which is currently to be sent by the first access network device with a second sequence number of a first MBS data packet which is currently to be sent by the second access network device, and determines that a switching policy used in the process that the terminal device is switched from the first access network device to the second access network device is non-DAPS switching when the first sequence number is greater than the second sequence number, wherein the non-DAPS switching can also be called conventional switching.

S1101: the method comprises the steps that a first access network device sends a switching Request (HO Request) to a second access network device, the switching Request comprises a first sequence number, and the first sequence number (marked as SN 1) is the sequence number of a first MBS data packet to be sent to a terminal device by the first access network device in a multicast mode.

The first access network device may be a base station to which the terminal device is currently accessed, the second access network device may be a base station to which the terminal device is to be switched and accessed, and the first access network device may determine, through information such as a measurement report of the terminal device, whether the terminal device is switched and determine the second access network device to which the terminal device is switched. And after the first access network device determines that the terminal device is switched to the second access network device, sending a switching request message to the second access network device, wherein the switching request message includes relevant information for the second access network device to determine the switching of the terminal device. In addition, the switching request may further include a SN1, so that the second access network device may determine a first sequence number of a next MBS data packet that is currently to be sent by the first access network device.

S1102: the second access network device performs admission control on the terminal device according to the handover request message received in S1101, and further determines a second sequence number (denoted as SN 2) of a next MBS data packet that the second access network device is currently about to send, and compares SN2 with SN1 included in the handover request message. The first sequence number and the second sequence number correspond to the same MBS service data and may be recorded as data of the first service. The first service may specifically be an MBS/MBMS service, which may also be referred to as a multicast service, or a multimedia broadcast multicast service, etc.

In this embodiment, it is assumed that SN1 > SN2, that is, the sequence number of the next MBS data packet to be sent by the first access network device is greater than the sequence number of the next MBS data packet sent by the second access network device. For example, one MBS service is split into MBS data packets with sequence numbers 1 to 100, and the first access network device and the second access network device multicast and send the MBS data packets separately, but due to the difference between services processed by the two base stations, when the first access network device sends an MBS data packet with sequence number SN1 of 50 at the first time, the second access network device sends an MBS data packet with sequence number SN2 of 30 at the same first time. That is to say, before the terminal device switches to the first access network device, it has received the MBS data packet with sequence number 1-50 in the MBS service, at this time, if the terminal device switches from the first access network device to the second access network device, it will continue to receive the MBS data packet with sequence number 30 sent from the second access network device, although the terminal device will repeatedly receive the MBS data packet with sequence number 31-50, the MBS data packets received by the terminal device before and after the switching are continuous and will not be interrupted, and the terminal device can obtain the complete MBS service. Therefore, the second access network device may determine that the terminal device directly establishes a connection with the second access network device and disconnects the connection handover with the first access network device when the first access network device is handed over to the second access network device, and other handover policies are not needed to maintain the continuity of the MBS data packets.

Optionally, the comparison between the first sequence number and the second sequence number performed by the second access network device in S1102 is to determine the progress of multicast transmission of the same MBS service data by the first access network device and the second access network device, so in other possible implementations, the first sequence number may also be a sequence number of a last MBS data packet that has been sent by the first access network device before the first time, and correspondingly, the second sequence number may be a sequence number of a last MBS data packet that has been sent by the second access network device before the same first time. At this time, the second access network device may also determine the two sequence numbers through S1102, and determine that the terminal device performs the non-DAPS handover when the first sequence number is greater than the second sequence number.

S1103: after determining that the terminal device performs non-DAPS handover through S1102, the second access network device sends handover Request acknowledgement (HO Request ACK) information to the first access network device, where the handover Request acknowledgement information includes indication information used to indicate, to the first access network device, that the terminal device uses a conventional handover policy during handover, and the indication information in this embodiment may be release indication information, which is denoted as first indication information, and the first indication information may also be a bit (set to true or false) indicating non-DAPS handover. Correspondingly, the first access network equipment receives the switching request confirmation information of the first indication information sent by the second access network equipment.

S1104: the first access network device may determine, according to the first indication information received by the second access network device in S1103, that the terminal device uses non-DAPS handover during handover, that is, conventional handover, and does not need to forward MBS service data to the second access network device, and the first access network device does not need to continue sending MBS data packets after SN1 to the terminal device, but only needs to instruct the terminal device to perform conventional RRC connection reconfiguration.

In summary, by determining the handover policy process of the terminal device by the second access network device in S1101-S1104 of this embodiment, when the terminal device is handed over from the first access network device to the second access network device, the first access network device reports the first sequence number of the first MBS data packet to be sent to the second access network device, so that the second access network device can determine that the progress of sending the MBS data packet by the second access network device is slower according to the fact that the first sequence number is greater than the second sequence number of the first MBS data packet to be sent by the second access network device, and for the same MBS service data to which the MBS data packet belongs, the terminal device has received more MBS data packets at the first access network device, and no MBS data packet interruption or loss occurs after the terminal device is handed over to the second access network device, thereby determining that the terminal device can use a conventional handover policy when being handed over from the first access network device to the second access network device. And after determining the conventional switching strategy, the second access network device also sends first indication information to the first access network device, and indicates the conventional switching strategy to the first access network device, so that the first access network device and the second access network device can both execute the conventional switching strategy in the subsequent terminal device switching process. Therefore, the conventional switching strategy determined by the second access network device in this embodiment can avoid service interruption of the terminal device in the switching process, so that the access network device can also determine the terminal device switching strategy in the multicast communication scene, thereby ensuring service continuity during terminal device switching, and finally improving the technical effect of the communication efficiency of the terminal device.

A second part: after the first portion of the second access network devices determines that the terminal device performs a non-DAPS handover, the terminal device uses the non-DAPS handover in a handover from the first access network device to the second access network device.

S1105: specifically, the first access network device may instruct the terminal device to switch the RRC connection from the first access network device to the second access network device by sending an RRC connection reconfiguration message (RRCReconfiguration) to the terminal device, so that the terminal device performs a conventional handover. The RRC connection reconfiguration message may further include information related to the terminal device switching to the second access network device.

S1106: then, for the terminal device, it is determined to perform the conventional handover according to the RRC connection reconfiguration message sent by the first access network device received in S1105, and the terminal device may release the RRC connection with the first access network device and establish the RRC connection with the second access network device in S1106.

S1107: after the terminal device completes the reconfiguration handover of the RRC connection in S1106, the second access network device may send an rrcreeconfigurationcomplete message to confirm that the terminal device completes the reconfiguration handover of the RRC connection.

S1108: after the second access network device determines that the terminal device completes RRC reconfiguration, it may send a PATH SWITCH REQUEST (PATH SWITCH REQUEST) message to the AMF entity, trigger the 5GC side to SWITCH the DL data PATH of the terminal device to the second access network device, and establish an NG-C interface instance facing the second access network device.

S1109: in S1109, the 5GC switches the DL data path of the terminal device to the second access network device, and the UPF sends one or more "end marker" packets to the first access network device on the old path per PDU session/tunnel, and may then release any user plane/TNL resources to the first access network device.

S1110: after completing the PATH switching, the AMF confirms the PATH switching success to the second access network device by using a PATH SWITCH REQUEST ACKNOWLEDGE message PATH SWITCH REQUEST ACKNOWLEDGE.

S1111: the second access network equipment informs the first access network equipment of the successful switching of the terminal equipment through the UE Context Release message, and the first access network equipment releases resources related to the terminal equipment to complete the whole process of switching the terminal equipment from the first access network equipment to the second access network equipment.

In summary, through S1105-S1111 of this embodiment, the terminal device completes a conventional handover process from the first access network device to the second access network device, and since the progress of sending the MBS data packet by the second access network device is slower, it is determined that the terminal device has received more MBS data packets at the first access network device, and MBS data packets received by the terminal device from the first access network device and the second access network device before and after handover may even be repeated to a certain extent, thereby ensuring continuity of multicast data received by the terminal device when switching the base station, and finally improving communication efficiency of the terminal device.

Fig. 12 is a flowchart of a fifth embodiment of the communication method provided by the present application, and the communication method shown in fig. 12 may be applied to a scenario in which the terminal device shown in fig. 3 is switched from a first access network device to a second access network device. Specifically, the communication method provided by the present embodiment includes:

a first part: in the process that the terminal equipment is switched from the first access network equipment to the second access network equipment, the second access network equipment compares a first sequence number of a first MBS data packet which is to be sent by the first access network equipment at present with a second sequence number of a first MBS data packet which is to be sent by the second access network equipment at present, and when the first sequence number is smaller than the second sequence number, the DAPS switching is used in the process that the terminal equipment is switched from the first access network equipment to the second access network equipment.

S1201: the first access network equipment sends a handover Request (HO Request) to the second access network equipment, where the handover Request includes a first sequence number (marked as SN 1) of an MBS data packet to be sent by the first access network equipment to the terminal equipment in a multicast manner.

The first access network device may be a base station to which the terminal device is currently accessed, the second access network device may be a base station to which the terminal device is to be switched and accessed, and the first access network device may determine, through information such as a measurement report of the terminal device, whether the terminal device is switched and determine the second access network device to which the terminal device is switched. Then, after the first access network device determines that the terminal device is switched to the second access network device, a switching request message is sent to the second access network device, where the switching request message includes relevant information for the second access network device to determine the switching of the terminal device. In addition, the handover request message further includes SN1, so that the second access network device can determine the first sequence number of the next MBS data packet that the first access network device will send currently.

S1202: the second access network device performs admission control on the terminal device according to the handover request message received in S1201, and further determines a second sequence number (denoted as SN 2) of a next MBS data packet that the second access network device is currently about to send, and compares SN2 with SN1 included in the handover request message. The first sequence number and the second sequence number correspond to the same MBS service data and may be recorded as data of the first service. The first service may specifically be an MBS/MBMS service, which may also be referred to as a multicast service, or a multimedia broadcast multicast service, etc.

In this embodiment, it is assumed that SN2 > SN1, that is, the sequence number of the first MBS data packet to be sent by the second access network device is greater than the sequence number of the first MBS data packet to be sent by the first access network device. For example, one MBS service data may be split into MBS data packets with sequence numbers 1 to 100, and the first access network device and the second access network device respectively multicast and send the MBS data packets, but due to the difference between services processed by the two base stations, when the first access network device is to send an MBS data packet with sequence number SN1 of 10, the second access network device is to send an MBS data packet with sequence number SN2 of 30. That is to say, before the terminal device switches to the first access network device, it only receives MBS data packets with sequence numbers 1 to 10 in the MBS service data, at this time, after the terminal device switches from the first access network device to the second access network device, it will receive MBS data packets with sequence numbers 30 and later sent from the second access network device, which causes that the terminal device cannot receive 11 to 30 sent by any access network device in the switching process, so that the terminal device cannot receive all continuous MBS data packets in the MBS service data, and causes interruption of the MBS service data. Therefore, the second access network device may determine that the terminal device is switched from the first access network device to the second access network device according to SN1 < SN2, and may use DAPS switching to maintain the continuity of MBS data packets.

Optionally, the first sequence number in S1202 may also be a sequence number of a last MBS data packet that has been sent by the first access network device before the first time, and correspondingly, the second sequence number may be a sequence number of a last MBS data packet that has been sent by the second access network device before the same first time. At this time, the second access network device may also determine the two sequence numbers through S1202, and determine that the terminal device performs DAPS handover when the first sequence number is smaller than the second sequence number.

S1203: after determining that the terminal device performs the DAPS handover through S1202, the second access network device sends handover Request acknowledgement (HO Request ACK) information to the first access network device, where the handover Request acknowledgement information includes indication information used to indicate, to the first access network device, that the terminal device uses a DAPS handover policy during handover, and the indication information in this embodiment may be a DAPS indication, which is denoted as second indication information, and the second indication information may also be a bit (set to true or false) indicating the DAPS handover. Correspondingly, the first access network equipment receives the switching request confirmation information which is sent by the second access network equipment and comprises the second indication information. Optionally, the handover request acknowledgement message may further include SN2.

S1204: the first access network device may determine that the terminal device uses the DAPS handover policy during handover according to the DAPS indication received by the second access network device in S1203.

In summary, by determining the handover policy process of the terminal device by the second access network device in S1201-S1204 of this embodiment, when the terminal device is handed over from the first access network device to the second access network device, the first access network device reports the sequence number of the MBS data packet to be sent to the second access network device, so that the second access network device can determine that the DAPS handover can be used when the terminal device is handed over from the first access network device to the second access network device, because the schedule for sending the MBS data packet by the second access network device is faster, and a part of the MBS data packet is interrupted and lost after the terminal device is handed over from the first access network device with a slower sending schedule to the second access network device, according to the fact that the sequence number of the MBS data packet to be sent by the first access network device is smaller than the sequence number of the MBS data packet to be sent by the second access network device itself. And after determining the conventional handover strategy, the second access network device also sends a DAPS indication to the first access network device, and indicates the DAPS handover to the first access network device, so that the first access network device and the second access network device can both execute the DAPS handover in the subsequent terminal device handover process. Therefore, the DAPS handover policy determined by the second access network device in this embodiment can avoid service interruption of the terminal device during handover, and the access network device can also determine the terminal device handover policy in a multicast communication scenario, thereby ensuring service continuity during handover of the terminal device, and finally improving the technical effect of communication efficiency of the terminal device.

Therefore, in connection with the methods shown in S1101-S1104 and S1201-S1204, the second access network device serves as the execution subject, in the process that the terminal equipment is switched from the first access network equipment to the second access network equipment, the switching request sent by the first access network equipment to the second access network equipment comprises the serial number of the MBS data packet to be sent by the first access network equipment, thereby realizing the interaction of the serial numbers of the MBS data packets between the two base stations, the second access network equipment can determine the sending progress of the MBS data packet of the first access network equipment, the second access network equipment can compare the sequence number of the MBS data packet to be sent by the first access network equipment with the sequence number of the MBS data packet to be sent by the second access network equipment, and determining that the terminal device uses a conventional handover or a DAPS handover when switching from the first access network device to the second access network device in a multicast scenario, thereby ensuring that the terminal equipment can use DAPS switching to ensure the continuity of the MBS service data received by the terminal equipment when the terminal equipment switches the base station, especially when the progress of sending the MBS data packet by the second access network equipment is faster and the progress of sending the MBS data packet by the first access network equipment is slower, so that the schedules for sending data packets between the first access network device and the second access network device are different, the second access network device may determine a corresponding handover policy to avoid service interruption by the terminal device during the handover, thereby realizing that the access network equipment can also determine the terminal equipment switching strategy in the multicast communication scene, and then the service continuity when the terminal equipment is switched is ensured, the communication quality of the terminal equipment during switching is improved, and finally the communication efficiency and the user experience of the terminal equipment are improved.

A second part: after the first portion of the second access network devices determine that the terminal device performs a DAPS handover, the terminal device uses the DAPS handover in a handover from the first access network device to the second access network device.

S1205: specifically, the first access network device may send an RRC connection reconfiguration message (rrcreeconfiguration) to the terminal device, and include a DAPS indication in the rrcreeconfiguration, for instructing the terminal device to execute a DAPS handover policy. The RRC connection reconfiguration message may further include information related to the terminal device switching to the second access network device.

S1206: then, for the terminal device, it determines to execute the DAPS handover policy according to the DAPS indication included in the RRC connection reconfiguration message sent by the first access network device received in S1205, and the terminal device may specifically maintain the RRC connection with the first access network device when establishing the RRC connection with the second access network device in S1206, that is, the terminal device may simultaneously connect with the first access network device and the second access network device in the handover process, and may receive downlink communication data sent by the two base stations, including MBS data packets belonging to the same MBS service data.

S1207: after the terminal device completes establishing with the second access network device in S1206, the second access network device may send an rrcreeconfigurationcomplete message to confirm that the terminal device completes the reconfiguration of the RRC connection.

S1208: the second access network device then sends a handover SUCCESS message HO SUCCESS to the first access network device, informing the first access network device that the terminal device has accessed the second access network device. Meanwhile, the second access network device further includes a third sequence number (denoted as SN 3) in the handover SUCCESS message HO SUCCESS, where SN3 is a sequence number of a first MBS data packet to be currently sent by the second access network device. That is, the second access network device confirms in S1207 that the RRC connection with the terminal device has been successfully established, after the second access network device establishes the RRC connection with the terminal device at the second time, the second access network device may send the MBS data packet to the terminal device, and note that the third sequence number of the first MBS data packet that the second access network device is about to send to the terminal device at the second time is SN3, that is, the sequence number of the first MBS data packet that the terminal device can receive after accessing the second access network device is SN3. It can be understood that since the second access network device determines SN1 and SN2 in S1202 and then sends SN3 to the first access network device in S1208, the second access network device is still sending MBS data packets in the time period from S1202 to S1208, so SN3 is greater than or equal to SN2. Meanwhile, the progress of sending the MBS data packet by the second access network device is faster than that of the first access network device, and the second access network device needs to send the SN3 to the first access network device, so that the first access network device continues to send the MBS data packet before the SN3 to the terminal device in the course of performing DAPS handover by the terminal device.

S1209: in this embodiment, after receiving the handover success message, the first access network device does not immediately terminate data transmission with the terminal device, but continues to send MBS data packets to the terminal device. It is assumed that at a second time when the first access network device receives the handover success message sent by the second access network device at S1208, the first data packet to be sent is a fourth MBS data packet, and the sequence number of the fourth MBS data packet is SN4, because the progress of the data packet sent by the first access network device in this embodiment lags behind that of the second access network device, so SN4 is less than SN3, the first access network device may continue to send MBS data packets with sequence numbers SN4-SN3 to the terminal device after receiving the handover success message and determining SN 3. The first access network device may further include end indication information (e.g., end marker) in the last data packet sent to the terminal device in S1209, or indicate, through other means such as MAC CE, that the first access network device has completed data transmission to the terminal device, that is, the MBS data packets between SN4 and SN3 have been sent to the terminal device.

S1210: after the second access network device determines to establish RRC connection with the terminal device in S1207, it may send an MBS data packet to the terminal device, and since the progress of sending the MBS data packet by the second access network device is fast and the MBS data packet with the sequence number SN3 is already sent, the second access network device may continue to send the MBS data packet with the sequence number SN3 to the terminal device. It should be noted that, the sequence of S1209 and S1210 is not distinguished during execution, and for the terminal device, the MBS data packet before the sequence number SN3 sent by the first access network device may be received at the same time, and the MBS data packet after the sequence number SN3 sent by the second access network device may be received.

S1211: after the first access network device sends all MBS data packets before the sequence number SN3 to the terminal device, the first access network device may send end indication information to the second access network device, where the end indication information is used to indicate that the first access network device has completed data transmission to the terminal device, that is, MBS data packets between SN4 and SN3 have been sent to the terminal device.

S1212: the second access network device sends a PATH SWITCH REQUEST (PATH SWITCH REQUEST) message to the AMF entity, triggers 5GC side to SWITCH the DL data PATH of the terminal device to the second access network device, and establishes an NG-C interface instance towards the second access network device.

S1213: the 5GC switches the DL data path of the terminal device to the second access network device, the UPF sends one or more "end marker" packets to the first access network device per PDU session/tunnel on the old path, and may then release any user plane/TNL resources to the first access network device.

S1214: after completing the PATH switching, the AMF uses a PATH SWITCH REQUEST ACKNOWLEDGE message PATH ACKNOWLEDGE to ACKNOWLEDGE the PATH SWITCH REQUEST to the second access network device.

The above-described S1212-S1214 may be completed at any time between S1208-S1215 in order.

S1215: finally, when the second access network device determines through S1211 that the first access network device has sent the MBS data packet before SN4-SN3 to the terminal device, the first access network device may be notified through the UE Context Release message to Release the resource related to the terminal device.

S1216: and the second access network equipment sends an indication for releasing the connection with the first access network equipment to the terminal equipment, so that the terminal equipment is disconnected with the first access network equipment.

S1217: then, for the terminal device, since the MBS data packets sent from the first access network device and the second access network device are received at the same time, the terminal device sequences the MBS data packets received from the first access network device and the second access network device respectively during the handover process. S1217 may be executed after S1209 and S1210, that is, after the terminal device starts to simultaneously receive the MBS data packets sent by the first access network device and the second access network device, S1217 may be executed.

Specifically, for the terminal device, in the entire DAPS handover process where S1208-S1216 access the second access network device and finally disconnect the connection with the first access network device, both at least one data packet from the first access network device and at least one data packet from the second access network device are received, where at least one data packet received by the terminal device in the DAPS handover process from the first access network device may be an MBS data packet with a sequence number of SN4-SN3, and at least one data packet received by the terminal device in the DAPS handover process from the second access network device may be an MBS data packet with a sequence number of SN3, and then the PDCP layer of the terminal device may order at least one MBS data packet received during the DAPS handover process from the first access network device according to the PDCP sequence number, first order at least one ordered data packet received by the upper layer from the first access network device, and after determining that the last data packet from the first access network device has been delivered to the upper layer through the end indication information, order at least one ordered data packet received by the second access network device according to the PDCP sequence number, and then order at least one ordered data packet received by the second access network device. It should be noted that the terminal device may simultaneously and respectively sequence the MBS data packets from the first access network device and the second access network device, but when delivering to the upper layer, the terminal device must complete the sequential delivery of the MBS data packets from the first access network device before delivering the MBS data packets from the second access network device in sequence. The submitting to the upper layer means that the PDCP layer of the terminal device sorts the received MBS data packets, and then submits the sorted MBS data packets to a main body of the application layer, such as an application program in an operating system operated by the terminal device, to further process the MBS data packets. It can be understood that, when the terminal device completes the DAPS handover procedure, it will continue to receive MBS data packets from the second access network device, and after sequencing, deliver them to the upper layer in sequence.

In summary, through this embodiment S1205-S1217, the terminal device completes the DAPS handover procedure from the first access network device to the second access network device, and because the schedule for sending the MBS data packet by the first access network device lags behind the MBS data packet sent by the second access network device, when the terminal device performs the handover of the access network device, after the connection is established with the second access network device, the connection with the first access network device is not immediately disconnected, but the terminal device continues to receive the MBS data packet from the first access network device. For the terminal device, after establishing connection with the second access network device and starting to receive the first MBS data packet from the second access network device, the terminal device also receives the MBS data packet from the first access network device at the same time, so that the MBS data packet received by the terminal device from the first access network device and the MBS data packet received by the second access network device are kept continuous without being terminated. Finally, after the terminal device receives the MBS data packet sent by the first access network device from the first access network device, the terminal device may disconnect the connection with the first access network device under the instruction of the second access network device, and finally complete the entire handover process. Therefore, the embodiment can be applied to a multicast communication scenario, and when the progress of sending the MBS data packet by the first access network device lags behind the MBS data packet sent by the second access network device, the multicast data received by the terminal device during switching can have continuity, so that the communication efficiency of the terminal device is ensured, and the communication efficiency of the terminal device is finally improved.

Fig. 13 is a flowchart illustrating a sixth embodiment of the communication method provided by the present application, where the communication method shown in fig. 13 is applicable to a scenario in which the terminal device shown in fig. 3 is switched from a first access network device to a second access network device. More specifically, the communication method provided in this embodiment includes:

S1301: the method comprises the steps that a first access network device sends a switching Request (HO Request) to a second access network device, wherein the switching Request comprises a first mapping relation and a first PDCP sequence number (marked as PDCP SN 1), the first PDCP sequence number is the PDCP sequence number of a first data packet, the first data packet is a first MBS data packet to be sent by the first access network device, and the first mapping relation is used for indicating the corresponding relation between the sequence number of the MBS data packet sent by the first access network device and the PDCP sequence number of the MBS data packet sent by the first access network device. For example, in the example shown in fig. 5, the first access network device sends MBS data packets with sequence numbers 15-18 to the terminal device, the PDCP sequence numbers of these MBS data packets are 100-103 in sequence, and the second access network device sends MBS data packets with sequence numbers 30-33, and the PDCP sequence numbers of these MBS data packets are 50-53 in sequence. The sequence number of the MBS data packet is determined by the UPF, the two access network devices maintain the PDCP sequence numbers respectively, when the terminal device is accessed to the first access network device, the PDCP sequence number of the MBS data packet sent by the first access network device can be obtained through the PDCP layer, and when the terminal device is accessed to the second access network device, the PDCP sequence number of the MBS data packet sent by the second access network device can be obtained through the PDCP layer. In this step, the first mapping relationship sent by the first access network device to the second device may be used to indicate the PDCP sequence number of the MBS data packet sent by the first access network device to the terminal device, so that the second access network device may determine the sequence number SN1 of the first data packet according to the PDCP SN1 sent by the first access network device in combination with the first mapping relationship.

Or, in S1301, the access network device may include the first mapping relationship and the first sequence number in the handover request, so that the second access network device may directly obtain the SN1 included in the handover request.

S1302: the second access network device performs admission control on the terminal device according to the handover request message received in S1001, and also determines a second sequence number (marked as SN 2) of a next MBS data packet that the second access network device is currently about to send, and compares SN2 with SN1. The first sequence number and the second sequence number correspond to the same MBS service data and may be recorded as data of the first service. The first service may specifically be an MBS/MBMS service, which may also be referred to as a multicast service, or a multimedia broadcast multicast service, etc.

Specifically, after the second access network device receives the first mapping relationship and the PDCP SN1 sent by the first access network device in S1301, the second access network device determines SN1 through the PDCP SN1 and the first mapping relationship in S1302, and then compares SN1 with SN 2.

In this embodiment, assuming SN1 > SN2, the second access network device may determine that the terminal device performs a non-DAPS handover when the first access network device is handed over to the second access network device, which may also be referred to as a conventional handover policy.

Optionally, in S1302, the first sequence number may also be a sequence number of a last MBS data packet that has been sent by the first access network device before the first time, and correspondingly, the second sequence number may be a sequence number of a last MBS data packet that has been sent by the second access network device before the same first time. At this time, the second access network device may also determine the two sequence numbers through S1302, and determine that the terminal device performs the non-DAPS handover when the first sequence number is greater than the second sequence number.

Further, after the second access network device determines that the terminal device performs the non-DAPS handover, the second access network device sends indication information to the first access network device, so as to indicate the first access network device that the terminal device uses the non-DAPS handover during the handover. Therefore, in a first implementation (1) in which, after S1302, the second access network device sends the indication information to the first access network device, reference may be made to S1303a-S1305a, where:

s1303a: the second access network device sends handover Request acknowledgement (HO Request ACK) information to the first access network device, and the handover Request acknowledgement includes indication information for indicating to the first access network device that the terminal device uses a conventional handover policy during handover, where the indication information in this embodiment may be a release indication, which is denoted as first indication information, and the first indication information may also be one bit (set to true or false) indicating conventional handover; meanwhile, the handover request acknowledgement further includes a second mapping relationship, where the second mapping relationship is used to indicate a correspondence relationship between a sequence number of a data packet sent by the second access network device and a PDCP sequence number of the data packet sent by the second access network device.

S1304a: the first access network device can determine that the terminal device uses non-DAPS switching during switching according to the first indication information in the received switching request confirmation, namely, conventional switching, and does not need to forward MBS service data to the second access network device, and the first access network device does not need to continuously send MBS data packets after SN1 to the terminal device, but only needs to indicate the terminal device to perform conventional RRC connection reconfiguration.

S1305a: the first access network device further determines a third mapping relationship according to a second mapping relationship in the received handover request in combination with the first mapping relationship, where the third mapping relationship is used to indicate a correspondence relationship between a PDCP sequence number of a packet sent by the first access network device and a PDCP sequence number of a packet sent by the second access network device. For example, taking fig. 5 as an example, the first mapping relationship may be used to indicate a corresponding relationship between sequence numbers 15-18 of MBS data packets sent by the first access network device and PDCP sequence numbers 100-103 of the data packets, the second mapping relationship may be used to indicate a corresponding relationship between sequence numbers 30-33 of MBS data packets sent by the second access network device and PDCP sequence numbers 50-53 of the data packets, and the third mapping relationship may be used to indicate a corresponding relationship between PDCP sequence numbers 100-103 of MBS data packets sent by the first access network device and PDCP sequence numbers 50-53 of MBS data packets sent by the second access network device. In a simple implementation manner of the third mapping relationship, the third mapping relationship may also be represented by a difference between PDCP sequence numbers. The third mapping relationship may be used when the terminal device receives the MBS data packets sent by the first access network device and the second access network device at the same time, and the PDCP layer may obtain PDCP sequence numbers of the first access network device and the second access network device, and perform sequential delivery on the MBS data packets according to the sequence of the PDCP sequence numbers by combining with the third mapping relationship.

After S1302, in a second implementation (2) in which the second access network device sends the indication information to the first access network device, reference may be made to S1303b-S1305b, where:

s1303b: the second access network device determines the third mapping relationship by combining the first mapping relationship and the second mapping relationship received in S1301.

S1304b: the second access network device sends the handover request acknowledgement to the first access network device, where the handover request acknowledgement includes the first indication information and the third mapping relationship determined in S1303 b.

Optionally, in S1304b, the handover request acknowledgement sent by the second access network device to the first access network device may further include the second mapping relationship and the third mapping relationship at the same time. S1305b: the first access network device can determine that the terminal device uses a conventional handover strategy during handover according to the first indication information in the received handover request acknowledgement.

It is to be understood that, in the above implementation manner (1), the second access network device determines the third mapping relationship, and in the implementation manner (2), one of the two manners of determining the third mapping relationship by the first access network device may be optionally executed, and after the first access network device determines or receives the third mapping relationship, the third mapping relationship is sent to the terminal device in a subsequent step, and is used by the terminal device when delivering the MBS data packets in sequence.

In summary, by determining the handover policy process through the second access network device in S1301-S1305a/S1305b of this embodiment, when the terminal device is handed over from the first access network device to the second access network device, the first access network device reports the first mapping relationship and the first PDCP sequence number, or the first mapping relationship and the first sequence number, to the second access network device, so that the second access network device can determine that, when the first sequence number is greater than the second sequence number of the first MBS data packet to be sent by the second access network device, the progress of sending the MBS data packet by the second access network device is slower, for the same MBS service data to which the MBS data packet belongs, the terminal device has received more MBS data packets at the first access network device, and a situation that the MBS data packet is interrupted and missing after the terminal device is handed over to the second access network device does not occur, thereby determining that the terminal device can use a conventional handover policy when handed over from the first access network device to the second access network device. And after determining the conventional switching strategy, the second access network device also sends first indication information to the first access network device, and indicates the conventional switching strategy to the first access network device, so that the first access network device and the second access network device can execute the conventional switching in the subsequent terminal device switching process. Therefore, the conventional switching strategy determined by the second access network device in this embodiment can avoid service interruption of the terminal device in the switching process, so that the access network device can also determine the terminal device switching strategy in the multicast communication scene, thereby ensuring service continuity during terminal device switching, and finally improving the technical effect of the communication efficiency of the terminal device.

A second part: after the first portion of the second access network devices determines that the terminal device performs a non-DAPS handover, the terminal device uses the conventional handover in a handover from the first access network device to the second access network device.

S1306: specifically, the first access network device may instruct the terminal device to switch the RRC connection from the first access network device to the second access network device by sending an RRC connection reconfiguration message (RRCReconfiguration) to the terminal device, so that the terminal device performs a conventional handover. The RRC connection reconfiguration message may further include information related to the terminal device switching to the second access network device, and include a third mapping relationship determined by the first access network device or the second access network device in the first portion.

S1307: then, for the terminal device, it is determined to perform the normal handover according to the RRC connection reconfiguration message sent by the first access network device received in S1306, and the terminal device may release the RRC connection with the first access network device and establish the RRC connection with the second access network device in S1307.

S1308: after the terminal device completes the reconfiguration handover of the RRC connection in S1307, the second access network device may send an rrcreeconfigurationcomplete message to confirm that the terminal device completes the reconfiguration handover of the RRC connection.

S1309: after the second access network device determines that the terminal device completes RRC reconfiguration, it may send a PATH SWITCH REQUEST (PATH SWITCH REQUEST) message to the AMF entity, trigger the 5GC side to SWITCH the DL data PATH of the terminal device to the second access network device, and establish an NG-C interface instance towards the second access network device.

S1310: in S1310, the 5GC switches the DL data path of the terminal device to the second access network device, and the UPF sends one or more "end marker" packets to the first access network device per PDU session/tunnel on the old path, and may then release any user plane/TNL resources to the first access network device.

S1311: after completing the PATH switching, the AMF confirms the successful PATH switching to the second access network device by using a PATH SWITCH REQUEST ACKNOWLEDGE message PATH SWITCH REQUEST ACKNOWLEDGE.

S1312: the second access network equipment informs the first access network equipment of the successful switching of the terminal equipment through the UE Context Release message, and the first access network equipment releases resources related to the terminal equipment to complete the whole process of switching the terminal equipment from the first access network equipment to the second access network equipment.

In summary, through S1306 to S1312 in this embodiment, the terminal device completes a conventional handover process from the first access network device to the second access network device, and because the schedule of sending the MBS data packet by the second access network device is slower, it is determined that the terminal device has received more MBS data packets at the first access network device, and MBS data packets received by the terminal device from the first access network device and the second access network device before and after the handover may even be repeated to a certain extent, so that continuity of multicast data received by the terminal device when switching the base station is ensured, and communication efficiency of the terminal device is finally improved.

Fig. 14 is a flowchart of a seventh embodiment of the communication method provided by the present application, and the communication method shown in fig. 14 may be applied to a scenario in which the terminal device shown in fig. 3 is switched from a first access network device to a second access network device. Specifically, the communication method provided by the present embodiment includes:

a first part: in the process that the terminal equipment is switched from the first access network equipment to the second access network equipment, the second access network equipment compares a first sequence number of a first MBS data packet which is to be sent by the first access network equipment currently and a second sequence number of a first MBS data packet which is to be sent by the second access network equipment currently, and when the first sequence number is smaller than the second sequence number, the DAPS switching is used in the process that the terminal equipment is switched from the first access network equipment to the second access network equipment.

S1401: the first access network device sends a handover Request (HO Request) to the second access network device, and the handover Request includes a first mapping relationship and a first PDCP sequence number (denoted as PDCP SN 1), where the first PDCP sequence number is a PDCP sequence number of a first data packet, the first data packet is a first MBS data packet to be sent by the first access network device, and the first mapping relationship is used to indicate a correspondence relationship between a sequence number of a data packet sent by the first access network device and a PDCP sequence number of a data packet sent by the first access network device, so that the second access network device may determine the sequence number SN1 of the first data packet by combining the first mapping relationship according to the PDCP SN1 sent by the first access network device. Or, the handover request in S1401 includes the first mapping relationship and the first sequence number, so that the second access network device can directly obtain the SN1 included in the handover request.

S1402: the second access network device performs admission control on the terminal device according to the handover request message received in S201, and the second access network device further determines a second sequence number (denoted as SN 2) of a next MBS data packet that the second access network device is about to send currently, and compares SN2 with SN1 included in the handover request message. The first sequence number and the second sequence number correspond to the same MBS service data and may be recorded as data of the first service. The first service may specifically be an MBS/MBMS service, which may also be referred to as a multicast service, or a multimedia broadcast multicast service, etc.

Specifically, after the second access network device receives the first mapping relationship and the PDCP SN1 sent by the first access network device in S1401, the second access network device determines SN1 through the PDCP SN1 and the first mapping relationship in S1402, and then compares SN1 and SN 2.

In this embodiment, assuming that SN2 > SN1, the second access network device may determine that the terminal device may use DAPS handover to ensure the continuity of MBS data packets when the first access network device is handed over to the second access network device.

Optionally, the first sequence number in S1402 may also be a sequence number of a last MBS data packet that has been sent by the first access network device before the first time, and correspondingly, the second sequence number may be a sequence number of a last MBS data packet that has been sent by the second access network device before the same first time. At this time, the second access network device may also determine the two sequence numbers through S202, and determine that the terminal device performs the DAPS handover when the first sequence number is smaller than the second sequence number.

Further, after determining that the terminal device performs DAPS handover, the second access network device sends indication information to the first access network device, so as to indicate, to the first access network device, that the terminal device uses DAPS handover during handover. Therefore, in a first implementation (1) where the second access network device sends the indication information to the first access network device after S1402, reference may be made to S1403a-S1405a, where:

s1403a: the second access network device sends handover Request acknowledgement (HO Request ACK) information to the first access network device, where the handover Request acknowledgement information includes indication information for indicating, to the first access network device, that the terminal device uses DAPS handover during handover, and the indication information in this embodiment may be a DAPS indication, which is denoted as second indication information, and the second indication information may also be a bit (set to true or false) indicating DAPS handover; meanwhile, the handover request acknowledgement further includes a second mapping relationship, where the second mapping relationship is used to indicate a correspondence relationship between a sequence number of a data packet sent by the second access network device and a PDCP sequence number of the data packet sent by the second access network device.

Optionally, in S1403a, the handover request acknowledgement sent by the second access network device to the first access network device may further include SN2 or PDCP SN2.

S1404a: the first access network device may determine that the handover policy used by the terminal device during handover is DAPS handover according to the second indication information in the received handover request acknowledgement.

S1405a: the first access network device further determines a third mapping relationship jointly according to a second mapping relationship in the received handover request and the first mapping relationship, wherein the third mapping relationship is used for indicating a corresponding relationship between a PDCP sequence number of a data packet sent by the first access network device and a PDCP sequence number of a data packet sent by the second access network device.

And after S1402, the second implementation (2) that the second access network device sends the indication information to the first access network device may refer to S1403b-S1405b, where:

s1403b: the second access network device determines the third mapping relationship by combining the first mapping relationship and the second mapping relationship received in S1401.

S1404b: the second access network device sends a handover request acknowledgement to the first access network device, where the handover request acknowledgement includes the first indication information and the third mapping relationship determined in S1403 b.

Optionally, in S1404b, the handover request acknowledgement sent by the second access network device to the first access network device may also include the second mapping relationship and the third mapping relationship at the same time.

Optionally, in S1404b, the handover request acknowledgement sent by the second access network device to the first access network device may further include SN2 or PDCP SN2.

S1405b: the first access network device may determine that the handover policy used by the terminal device during handover is DAPS handover according to the second indication information in the received handover request acknowledgement.

It can be understood that, in the above implementation manner (1), the second access network device determines the third mapping relationship, and in the implementation manner (2), the first access network device determines the third mapping relationship, which may be optionally executed, after the first access network device obtains the third mapping relationship, the third mapping relationship is sent to the terminal device in a subsequent step, and the terminal device uses the third mapping relationship when delivering the MBS data packets in sequence.

In summary, by determining the handover policy process of the terminal device by the second access network device in S1401-S1405a/S1405b of this embodiment, when the terminal device is handed over from the first access network device to the second access network device, the first access network device reports, to the second access network device, the first mapping relationship and the first PDCP sequence number of the first MBS data packet to be sent, or the first mapping relationship and the first sequence number, so that the second access network device can determine that the progress of sending the MBS data packet by the second access network device is faster according to the fact that the first sequence number is smaller than the second sequence number of the second access network device itself to send the first MBS data packet, and thus, when determining that the terminal device is handed over from the first access network device to the second access network device, the DAPS handover may be used. And after determining the conventional handover strategy, the second access network device also sends second indication information to the first access network device, and indicates the DAPS handover to the first access network device, so that the first access network device and the second access network device can both execute the DAPS handover in the subsequent terminal device handover process. Therefore, in this embodiment, the DAPS handover policy determined by the second access network device may avoid service interruption during the handover of the terminal device, so that the access network device may also determine the terminal device handover policy in a multicast communication scenario, thereby ensuring service continuity during handover of the terminal device, and finally improving the technical effect of communication efficiency of the terminal device.

Therefore, in combination with the methods shown in S1301-S1305a/S1305b and S1401-S1405a/S1405b, the second access network device is used as an execution main body, and in the process that the terminal device is switched from the first access network device to the second access network device, the handover request sent by the first access network device to the second access network device includes the first mapping relationship and the sequence number of the MBS data packet to be sent by the first access network device, or includes the first mapping relationship and the first PDCP sequence number, so that the interaction of the sequence numbers of the MBS data packets between the two base stations is realized, the second access network device can determine the sending progress of the MBS data packet of the first access network device, so that the second access network device can compare the sequence number of the MBS data packet to be sent by the first access network device with the sequence number of the MBS data packet to be sent by the second access network device itself, and determining that the terminal device uses conventional handover or DAPS handover when switching from the first access network device to the second access network device in a multicast scenario, thereby ensuring that the terminal device can use DAPS handover to ensure the continuity of MBS service data received by the terminal device when switching the base station, especially when the progress of transmitting MBS data packets by the second access network device is faster and the progress of transmitting MBS data packets by the first access network device is slower, so that for the difference in progress of transmitting data packets between the first access network device and the second access network device, the second access network device can determine a corresponding handover policy to avoid service interruption of the terminal device during the handover, thereby enabling the access network device under the multicast communication scenario to also determine the handover policy of the terminal device, further ensuring the service continuity when the terminal device switches, and improving the communication quality of the terminal device during the handover, and finally, the communication efficiency and the user experience of the terminal equipment are improved.

S1405: specifically, the first access network device may send an RRC connection reconfiguration message (rrcreeconfiguration) to the terminal device, where the rrcreeconfiguration further includes a DAPS indication, and the DAPS indication may also be a bit (set to true or false) indicating DAPS handover, which is used to indicate the terminal device to execute a DAPS handover policy. The RRC connection reconfiguration message may further include the third mapping relationship determined in the first part, and information related to the terminal device switching to the second access network device.

S1407: then, for the terminal device, it determines to perform DAPS handover according to the DAPS indication included in the RRC connection reconfiguration message sent by the first access network device received in S1406, and the terminal device may specifically maintain RRC connection with the first access network device when establishing RRC connection with the second access network device in S1406, that is, the terminal device may be connected with the first access network device and the second access network device simultaneously in the handover process, and may receive downlink communication data sent by the two base stations, including MBS data packets belonging to the same MBS service data.

S1408: after the terminal device completes establishing the connection with the second access network device in S1407, the second access network device may send an rrcreeconfiguration complete message to confirm that the terminal device completes the reconfiguration of the RRC connection.

S1409: the second access network device then sends a handover SUCCESS message HO SUCCESS to the first access network device, informing the first access network device that the terminal device has accessed the second access network device. Meanwhile, the second access network device further includes a third sequence number (denoted as SN 3) in the handover SUCCESS message HO SUCCESS, where SN3 is a sequence number of a first MBS data packet to be currently sent by the second access network device.

Or, the handover success message sent by the second access network device to the first access network device includes a third PDCP sequence number, where the third PDCP sequence number is a PDCP sequence number of a third data packet, and the third data packet is a sequence number of a first MBS data packet to be sent by the current second access network device.

S1410: in this embodiment, after receiving the handover success message, the first access network device does not immediately terminate data transmission with the terminal device, but continues to send the MBS data packet to the terminal device. It is assumed that, at a second time when the first access network device receives the handover success message sent by the second access network device in S1409, the first data packet to be sent is a fourth MBS data packet, and the sequence number of the fourth MBS data packet is SN4, because the progress of the data packet sent by the first access network device in this embodiment lags behind that of the second access network device, so SN4 is less than SN3, the first access network device may continue to send MBS data packets with sequence numbers SN4-SN3 to the terminal device after receiving the handover success message and determining SN 3.

Alternatively, the first access network device may also determine the MBS data packet to be sent to the terminal device through the PDCP sequence number of the MBS data packet, for example, in S1410, the first access network device sends the MBS data packet between the PDCP sequence number PDCP SN4 of the fourth data packet and the PDCP sequence number PDCP SN3 of the third data packet to the terminal device. It should be noted that, because the first access network device and the second access network device respectively maintain their PDCP SNs, the PDCP SN4 and the PDCP SN3 are not directly compared, and need to be mapped to the same side PDCP SN or a third party PDCP SN according to the mapping relationship for comparison.

S1411: after the second access network device determines to establish the RRC connection with the terminal device in S1408, the second access network device may send the MBS data packet to the terminal device, and since the progress of sending the MBS data packet by the second access network device is fast and has already been sent to the MBS data packet with the sequence number SN3, the second access network device may continue to send the MBS data packet with the sequence number SN3 to the terminal device. Alternatively, the second access network device may also determine the MBS data packet to be sent to the terminal device by the PDCP sequence number of the MBS data packet, for example, in S1411, the second access network device sends the MBS data packet after the PDCP sequence number PDCP SN3 of the third data packet to the terminal device. It should be noted that, the sequence of S1410 and S1411 is not distinguished during execution, and for the terminal device, the MBS data packet before the sequence number SN3 sent by the first access network device may be received at the same time, and the MBS data packet after the sequence number SN4 sent by the second access network device may be received.

S1412: after the first access network device sends all MBS data packets before the sequence number SN3 to the terminal device, the first access network device may send end indication information to the second access network device, where the end indication information is used to indicate that the first access network device has completed data transmission to the terminal device, that is, has sent MBS data packets between SN4 and SN3 to the terminal device.

S1413: the second access network device also sends a PATH SWITCH REQUEST message to the AMF entity, triggering 5GC side to SWITCH the DL data PATH of the terminal device to the second access network device, and establishing an NG-C interface instance towards the second access network device.

S1414: the 5GC switches the DL data path of the terminal device to the second access network device, the UPF sends one or more "end marker" packets on the old path to the first access network device per PDU session/tunnel, and may then release any user plane/TNL resources to the first access network device.

S1415: after completing the PATH switching, the AMF uses a PATH SWITCH REQUEST ACKNOWLEDGE message PATH ACKNOWLEDGE to ACKNOWLEDGE the PATH SWITCH REQUEST to the second access network device.

The above-described S1413-S1415 can be performed sequentially at any time between S1409-S1416.

S1416: finally, when the second access network device determines through S1412 that the first access network device has sent the MBS data packet before SN4-SN3 to the terminal device, the UE Context Release message may notify the first access network device that the terminal device has been successfully switched, and the first access network device releases the resource related to the terminal device.

S1417: the second access network device may also send an indication to the terminal device to release the connection with the first access network device, such that the terminal device disconnects from the first access network device.

S1418: then, for the terminal device, since at least one MBS data packet sent from the first access network device and at least one MBS data packet sent from the second access network device are received at the same time, where at least one data packet received by the terminal device in the DAPS handover procedure from the first access network device may be an MBS data packet with sequence number SN4-SN3, and at least one data packet received by the terminal device in the DAPS handover procedure from the second access network device may be an MBS data packet with sequence number after SN 3. Therefore, in the switching process, the terminal device reorders the received MBS data packets according to the third mapping relationship and the PDCP sequence numbers of the MBS data packets received from the first access network device and the second access network device, and then delivers the received MBS data packets to the upper layer in sequence through the PDCP layer. S1418 may be executed after S1410 and S1411, that is, after the terminal device starts to receive the MBS data packets sent by the first access network device and the second access network device simultaneously, S1418 may be executed.

Specifically, the terminal device may obtain the PDCP sequence numbers of the first access network device and the second access network device through the PDCP layer, and the third mapping relationship may also represent the corresponding relationship between the PDCP sequence numbers of the two access network devices, so that for an MBS data packet received in the DAPS handover process, the terminal device may map the PDCP sequence number of the MBS data packet of the first access network device to the PDCP sequence number of the data packet of the second access network device according to the third mapping relationship, and then sort the data packets according to the PDCP sequence numbers of the second access network device, so as to obtain an MBS data packet with continuous sequence numbers; or, the terminal device may also map the PDCP sequence number of the MBS data packet of the second access network device to the PDCP sequence number of the data packet of the first access network device according to the third mapping relationship, and then perform sorting according to the PDCP sequence number of the first access network device, so as to obtain the MBS data packets with consecutive sequence numbers.

In summary, through the embodiments S1406-S1418, the terminal device completes the DAPS handover procedure from the first access network device to the second access network device, and because the progress of sending the MBS data packet by the first access network device lags behind the MBS data packet sent by the second access network device, when the terminal device performs handover of the access network device, after the terminal device establishes connection with the second access network device, the connection with the first access network device is not immediately disconnected, but the terminal device continues to receive the MBS data packet from the first access network device. For the terminal device, after establishing connection with the second access network device and starting to receive the first MBS data packet from the second access network device, the terminal device also receives the MBS data packet from the first access network device at the same time, so that the MBS data packet received by the terminal device from the first access network device and the MBS data packet received by the second access network device are kept continuous without being terminated. Finally, after the terminal device receives the MBS data packet sent by the first access network device from the first access network device, the terminal device may disconnect the connection with the first access network device under the instruction of the second access network device, and finally complete the entire handover process. Therefore, the embodiment can be applied to a multicast communication scenario, and when the progress of the MBS data packet sent by the first access network device lags behind the MBS data packet sent by the second access network device, the multicast data received by the terminal device during switching can have continuity, and finally, the communication efficiency of the terminal device is improved.

Fig. 15 is a flowchart illustrating an eighth embodiment of the communication method provided by the present application, where the communication method shown in fig. 15 is applicable to a scenario in which the terminal device shown in fig. 3 is switched from a first access network device to a second access network device. More specifically, the communication method provided in this embodiment includes:

a first part: in the process that the terminal device is switched from the first access network device to the second access network device, the first access network device compares a first sequence number of a first MBS data packet which is to be sent by the first access network device at present with a second sequence number of a first MBS data packet which is to be sent by the second access network device at present, and when the first sequence number is greater than the second sequence number, the switching strategy used in the process that the terminal device is switched from the first access network device to the second access network device is determined to be non-DAPS switching, which can also be called conventional switching.

S1501: the first access network device sends a handover Request (HO Request) to the second access network device.

Specifically, the first access network device may be a base station to which the terminal device is currently accessed, the second access network device may be a base station to which the terminal device is to be switched and accessed, and the first access network device may determine, through information such as a measurement report of the terminal device, whether the terminal device performs a handover and determine the second access network device to which the terminal device performs a handover. The first access network equipment sends a switching request message to the second access network equipment, wherein the included related information is used for the second access network equipment to determine the switching of the terminal equipment.

S1502: the second access network equipment receives the switching Request information, and after the operations such as admission control and the like are carried out, switching Request confirmation information (HO Request ACK) can be sent to the first access network equipment, wherein the switching Request confirmation information comprises a second sequence number, and the second sequence number (marked as SN 2) is the sequence number of a first MBS data packet to be sent to the terminal equipment by the second access network equipment in a multicast mode.

Specifically, after the second access network device receives the handover request sent from the first access network device in S1501, the SN2 may be included in the handover request, so that the first access network device can determine the sequence number of the next MBS data packet that the second access network device will send currently.

S1503: the first access network device determines a first sequence number (denoted as SN 1) of a next MBS data packet that the first access network device is about to send currently, and compares SN1 with a second sequence number SN2 included in the handover request acknowledgement message received in S1502. The first sequence number and the second sequence number correspond to the same MBS service data and may be recorded as data of the first service. The first service may specifically be an MBS/MBMS service, which may also be referred to as a multicast service, or a multimedia broadcast multicast service, etc.

In this embodiment, it is assumed that SN1 > SN2, that is, the sequence number of the next MBS data packet to be sent by the first access network device is greater than the sequence number of the next MBS data packet sent by the second access network device. At this time, the first access network device may determine that the terminal device directly establishes a connection with the second access network device and disconnects the connection switching with the first access network device when the first access network device is switched to the second access network device, and other switching policies are not needed to maintain the continuity of the MBS data packets.

Optionally, the comparison between the first sequence number and the second sequence number performed by the first access network device in S1503 is to determine the progress of multicast transmission of the same MBS service data by the first access network device and the second access network device, so in other possible implementations, the first sequence number may also be a sequence number of a last MBS data packet that has been sent by the first access network device before the first time, and correspondingly, the second sequence number may be a sequence number of a last MBS data packet that has been sent by the second access network device before the same first time. At this time, the first access network device may also determine the two sequence numbers through S1503, and determine that the terminal device performs non-DAPS handover when the first sequence number is greater than the second sequence number.

In summary, by determining the handover policy process of the terminal device by the first access network device in S1501-S1503 in this embodiment, when the terminal device is handed over from the first access network device to the second access network device, the second access network device reports the first sequence number of the first MBS data packet to be sent to the first access network device, so that the first access network device can determine that the progress of sending the MBS data packet by the second access network device is slower according to the fact that the first sequence number of the first MBS data packet to be sent by the first access network device is greater than the second sequence number, and for the same MBS service data to which the MBS data packet belongs, the terminal device already receives more MBS data packets at the first access network device, and no MBS data packet interruption or deletion occurs after the terminal device is handed over to the second access network device, thereby determining that the terminal device can use the conventional handover policy when being handed over from the first access network device to the second access network device. Therefore, the conventional switching strategy determined by the first access network device in this embodiment can avoid service interruption of the terminal device in the switching process, so that the access network device can also determine the switching strategy of the terminal device in the multicast communication scene, thereby ensuring service continuity when the terminal device is switched, and finally improving the technical effect of communication efficiency of the terminal device.

A second part: after the first portion of the first access network devices determines that the terminal device performs a non-DAPS handover, the terminal device uses the non-DAPS handover in a handover from the first access network device to the second access network device.

Steps S1504 to S1510 in fig. 15 can refer to the descriptions of steps S1105 to S1111 in fig. 11, and the specific implementation, principle, and technical effect are the same, and are not repeated herein.

Fig. 16 is a flowchart illustrating a ninth embodiment of the communication method provided by the present application, where the communication method shown in fig. 16 is applicable to a scenario in which the terminal device shown in fig. 3 is handed over from a first access network device to a second access network device. Specifically, the communication method provided by the present embodiment includes:

a first part: in the process that the terminal equipment is switched from the first access network equipment to the second access network equipment, the first access network equipment compares a first sequence number of a first MBS data packet which is to be sent by the first access network equipment currently and a second sequence number of a first MBS data packet which is to be sent by the second access network equipment currently, and when the first sequence number is smaller than the second sequence number, DAPS switching is used in the process that the terminal equipment is switched from the first access network equipment to the second access network equipment.

S1601: the first access network device sends a handover Request (HO Request) to the second access network device.

S1602: after receiving the handover Request and performing admission control and other operations, the second access network device may send handover Request acknowledgement information (HO Request ACK) to the first access network device, where the handover Request acknowledgement information includes a second sequence number, and the second sequence number (denoted as SN 2) is a sequence number of a first MBS data packet to be sent to the terminal device by the second access network device in a multicast manner.

Specifically, after the second access network device receives the handover request sent from the first access network device in S1601, the second access network device may include SN2 in the handover request, so that the first access network device can determine the sequence number of the next MBS data packet that the second access network device will send currently.

S1603: the first access network device determines a first sequence number (denoted as SN 1) of a next MBS data packet that the first access network device is about to send currently, and compares SN1 with a second sequence number SN2 included in the handover request acknowledgement message received in S1602. The first sequence number and the second sequence number correspond to the same MBS service data and may be recorded as data of the first service. The first service may specifically be an MBS/MBMS service, which may also be referred to as a multicast service, or a multimedia broadcast multicast service, etc.

In this embodiment, it is assumed that SN2 > SN1, that is, the sequence number of the first MBS data packet to be sent by the second access network device is greater than the sequence number of the first MBS data packet to be sent by the first access network device. At this time, the second access network device may determine that the terminal device may maintain the continuity of the MBS data packets using DAPS handover when the first access network device is handed over to the second access network device.

Optionally, the first sequence number in this embodiment may also be a sequence number of a last MBS data packet that has been sent by the first access network device before the first time, and correspondingly, the second sequence number may be a sequence number of a last MBS data packet that has been sent by the second access network device before the same first time. At this time, the first access network device may also determine the two serial numbers through S1603, and determine that the terminal device performs the DAPS handover when the first serial number is smaller than the second serial number.

In summary, by determining the handover policy process of the terminal device by the first access network device in this embodiment S1601-S1603, when the terminal device is handed over from the first access network device to the second access network device, the second access network device reports the second sequence number of the first MBS data packet to be sent to the first access network device, so that the first access network device can determine that the terminal device can use DAPS handover when handed over from the first access network device to the second access network device because the schedule of sending the MBS data packet by the second access network device is faster and a situation that part of the MBS data packet is interrupted and lost occurs after handing over from the first access network device with a slower sending schedule to the second access network device according to the fact that the sequence number of the MBS data packet to be sent by the first access network device is smaller than the second sequence number. Therefore, in this embodiment, the DAPS handover policy determined by the first access network device can avoid service interruption of the terminal device during handover, so that the access network device can also determine the terminal device handover policy in a multicast communication scenario, thereby ensuring service continuity during handover of the terminal device, and finally improving the technical effect of communication efficiency of the terminal device.

Thus, in connection with the methods shown in S1501-S1503 and S1601-S1603, the first access network device acts as the execution master, in the process that the terminal equipment is switched to the second access network equipment from the first access network equipment, the switching request confirmation information sent to the first access network equipment by the second access network equipment comprises the sequence number of a first MBS data packet to be sent by the second access network equipment, thereby realizing the interaction of the sequence numbers of the MBS data packets between two base stations, ensuring the sending progress of the MBS data packet of the second access network equipment by the first access network equipment, the first access network equipment can compare the sequence number of the MBS data packet to be sent by the first access network equipment with the sequence number of the MBS data packet to be sent by the second access network equipment, and determining that the terminal device uses a conventional handover or a DAPS handover when switching from the first access network device to the second access network device in a multicast scenario, thereby ensuring that the terminal equipment can use DAPS switching to ensure the continuity of the MBS service data received by the terminal equipment when the terminal equipment switches the base station, especially when the progress of the MBS data packet sent by the second access network equipment is faster and the progress of the MBS data packet sent by the first access network equipment is slower, so that the schedules for sending packets between the first access network device and the second access network device are different, the first access network device may determine a corresponding handover policy to avoid service interruption by the terminal device during handover, thereby realizing that the access network equipment can also determine the terminal equipment switching strategy in the multicast communication scene, and then the service continuity when the terminal equipment is switched is ensured, the communication quality of the terminal equipment when the terminal equipment is switched is improved, and finally the communication efficiency and the user experience of the terminal equipment are improved.

Steps S1604 to S1616 as the second part in fig. 16 may refer to the descriptions as S1205 to S1217 in fig. 12, and the specific implementation, principle and technical effect thereof are the same and will not be described again.

Fig. 17 is a flowchart of a tenth embodiment of the communication method provided by the present application, and the communication method shown in fig. 17 may be applied to a scenario in which the terminal device shown in fig. 3 is switched from a first access network device to a second access network device. More specifically, the communication method provided in this embodiment includes:

S1701: the method comprises the steps that a first access network device sends a switching Request (HO Request) to a second access network device, wherein the switching Request comprises a first mapping relation, and the first mapping relation is used for indicating the corresponding relation between the sequence number of an MBS data packet sent by the first access network device and the PDCP sequence number of the MBS data packet sent by the first access network device.

Further, in the embodiment, after the first access network device sends the first mapping relationship to the second access network device, the second access network device or the first access network device may determine the third mapping relationship, which is used when the terminal device delivers the MBS data packets in sequence, and when it is determined that an execution main body of the third mapping relationship is different, information included in the handover request acknowledgement sent to the first access network device by the second access network device is also different, which is described below separately.

In the method (1), the first access network device determines the third mapping relationship, which may refer to S1702a-S1704a, where:

s1702a: after receiving the handover Request and performing operations such as admission control, the second access network device may send handover Request acknowledgement (HO Request ACK) information to the first access network device, and include a second mapping relationship in the handover Request acknowledgement, where the second mapping relationship is used to indicate a correspondence between a sequence number of a data packet sent by the second access network device and a PDCP sequence number of the data packet sent by the second access network device. Meanwhile, the handover request acknowledgement information further includes a second sequence number SN2 of a second data packet or a second PDCP sequence number PDCP SN2, where the second data packet is a next MBS data packet to be sent by the second access network device, and the second PDCP sequence number is a PDCP sequence number of the second data packet.

S1703a: subsequently, the first access network device determines a first sequence number (denoted as SN 1) of a next MBS data packet that the first access network device is currently about to send, and compares SN1 with SN2 received in S1702 a. The first sequence number and the second sequence number correspond to the same MBS service data and may be recorded as data of the first service. The first service may specifically be an MBS/MBMS service, which may also be referred to as a multicast service, or a multimedia broadcast multicast service, etc.

Specifically, after the first access network device receives the second mapping relationship and the PDCP SN2 sent by the second access network device in S1702a, the first access network device further determines SN2 through the PDCP SN2 and the second mapping relationship in S1703a, and then compares SN1 with SN 2.

In this embodiment, assuming SN1 > SN2, the first access network device may determine that the terminal device performs a non-DAPS handover when the first access network device is handed over to the second access network device, which may also be referred to as a conventional handover policy.

S1704a: and the first access network equipment determines a third mapping relation jointly according to the received second mapping relation and the first mapping relation, wherein the third mapping relation is used for indicating the corresponding relation between the PDCP sequence number of the data packet sent by the first access network equipment and the PDCP sequence number of the data packet sent by the second access network equipment. The first access network device does not sort the order when performing steps S1704a and S1703 a.

In the manner (2), the second access network device determines the third mapping relationship, which may refer to S1702b-S1704b, where:

s1702b: the second access network device determines the third mapping relationship in combination with the first mapping relationship and the second mapping relationship received in S1701.

S1703b: the second access network device sends the handover request acknowledgement message to the first access network device, including the third mapping relationship determined in S1702b, and including the second sequence number SN2 or the second PDCP sequence number PDCP SN2.

S1704b: the first access network device may determine that the terminal device performs the non-DAPS handover when the first access network device is handed over to the second access network device according to SN1 > SN2.

In summary, by determining the handover policy process by the first access network device of S1701-S1704a/S1704b in this embodiment, when the terminal device is handed over from the first access network device to the second access network device, the second access network device reports the second mapping relationship and the second PDCP sequence number, or the second mapping relationship and the second sequence number, to the first access network device, so that the first access network device can determine that, when the second sequence number is smaller than the first sequence number of the first MBS data packet to be sent by the first access network device, the progress of sending the MBS data packet by the second access network device is slower, for the same MBS service data to which the MBS data packet belongs, the terminal device has received more MBS data packets at the first access network device, and no MBS data packet interruption or loss occurs after the terminal device is handed over to the second access network device, thereby determining that the terminal device can use a conventional handover policy when handed over from the first access network device to the second access network device. Therefore, the conventional switching strategy determined by the first access network device in this embodiment can avoid service interruption of the terminal device in the switching process, so that the access network device can also determine the terminal device switching strategy in the multicast communication scene, thereby ensuring service continuity during terminal device switching, and finally improving the technical effect of the communication efficiency of the terminal device.

Optionally, the first sequence number in this embodiment may also be a sequence number of a last MBS data packet that has been sent by the first access network device before the first time, and correspondingly, the second sequence number may be a sequence number of a last MBS data packet that has been sent by the second access network device before the same first time. At this time, the first access network device may also determine the two sequence numbers through S1704a or S1704b, and determine that the terminal device performs the non-DAPS handover when the first sequence number is greater than the second sequence number.

A second part: the terminal device uses the conventional handover in a handover procedure from the first access network device to the second access network device after the first portion of the first access network devices determines that the terminal device performs a non-DAPS handover.

Steps S1705 to S1711 in the second part of fig. 17 may refer to the descriptions in S1306 to S1312 in fig. 13, and the specific implementation, principle, and technical effect are the same, and are not described again.

Fig. 18 is a flowchart illustrating an eleventh embodiment of the communication method provided by the present application, where the communication method shown in fig. 18 is applicable to a scenario in which the terminal device shown in fig. 3 switches from the first access network device to the second access network device. Specifically, the communication method provided by the present embodiment includes:

A first part: in the process that the terminal equipment is switched from the first access network equipment to the second access network equipment, the first access network equipment compares a first sequence number of a first MBS data packet which is to be sent by the first access network equipment currently and a second sequence number of a first MBS data packet which is to be sent by the second access network equipment currently, and when the first sequence number is smaller than the second sequence number, the DAPS switching is used in the process that the terminal equipment is switched from the first access network equipment to the second access network equipment.

S1801: the method comprises the steps that a first access network device sends a handover Request (HO Request) to a second access network device, and the handover Request comprises a first mapping relation, wherein the first mapping relation is used for indicating the corresponding relation between the sequence number of an MBS data packet sent by the first access network device and the PDCP sequence number of the MBS data packet sent by the first access network device.

In the method (1), the first access network device determines the third mapping relationship, which may refer to S1802a to S1804a, where:

s1802a: after receiving the handover Request and performing operations such as admission control, the second access network device may send handover Request acknowledgement (HO Request ACK) information to the first access network device, and include a second mapping relationship in the handover Request acknowledgement, where the second mapping relationship is used to indicate a correspondence between a sequence number of a data packet sent by the second access network device and a PDCP sequence number of the data packet sent by the second access network device. Meanwhile, the handover request acknowledgement information further includes a second sequence number SN2 or a second PDCP sequence number PDCP SN2 of a second data packet, where the second data packet is a next MBS data packet to be sent by the second access network device, and the second PDCP sequence number is a PDCP sequence number of the second data packet.

S1803a: subsequently, the first access network device determines a first sequence number (denoted as SN 1) of a next MBS data packet that the first access network device is currently about to send, and compares SN1 with SN2 received in S1802 a. The first sequence number and the second sequence number correspond to the same MBS service data and may be recorded as data of the first service. The first service may specifically be an MBS/MBMS service, which may also be referred to as a multicast service, or a multimedia broadcast multicast service, etc.

Particularly, after the first access network device receives the second mapping relationship and the PDCP SN2 sent by the second access network device in S1802a, the first access network device further determines SN2 through the PDCP SN2 and the second mapping relationship in S1803a, and then compares SN1 and SN2.

In this embodiment, assuming that SN1 < SN2, the first access network device may determine that the terminal device performs a DAPS handover when the first access network device is handed over to the second access network device.

S1804a: and the first access network equipment determines a third mapping relation jointly according to the received second mapping relation and the first mapping relation, wherein the third mapping relation is used for indicating the corresponding relation between the PDCP sequence number of the data packet sent by the first access network equipment and the PDCP sequence number of the data packet sent by the second access network equipment. The first access network device does not perform the sequence when performing steps S1804a and S1803 a.

In the manner (2), the second access network device determines the third mapping relationship, which may refer to S1802b-S1804b, where:

s1802b: the second access network device determines the third mapping relationship according to the first mapping relationship and the second mapping relationship received in S1801.

S1803b: the second access network device sends the handover request acknowledgement information to the first access network device, including the third mapping relationship determined in S1802b, and including the second sequence number SN2 or the second PDCP sequence number PDCP SN2.

S1804b: the first access network device may determine, according to SN1 < SN2, that the terminal device performs DAPS handover when the first access network device is handed over to the second access network device.

It is to be understood that, in the above implementation manner (1), the second access network device determines the third mapping relationship, and in the implementation manner (2), the first access network device determines the third mapping relationship optionally by one of the two manners, and after the first access network device determines or receives the third mapping relationship, the third mapping relationship is sent to the terminal device in a subsequent step and used by the terminal device when delivering the MBS data packets in sequence.

Optionally, the first sequence number in this embodiment may also be a sequence number of a last MBS data packet that has been sent by the first access network device before the first time, and correspondingly, the second sequence number may be a sequence number of a last MBS data packet that has been sent by the second access network device before the same first time. At this time, the first access network device may also determine the two sequence numbers through S1804a or S1804b, and determine that the terminal device performs the DAPS handover when the first sequence number is smaller than the second sequence number.

In summary, by determining the handover policy process of the terminal device by the first access network device in S1801-S1804a/S1804b of this embodiment, when the terminal device is handed over from the first access network device to the second access network device, the second access network device reports the first mapping relationship and the first PDCP sequence number, or the first mapping relationship and the first sequence number, to the first access network device, so that the first access network device can determine that the progress of sending the MBS data packet by the second access network device is faster when the second sequence number is greater than the first sequence number of the first MBS data packet to be sent by the first access network device itself, and thus it is determined that the terminal device can use DAPS handover when handed over from the first access network device to the second access network device. Therefore, in this embodiment, the DAPS handover policy determined by the first access network device can avoid service interruption of the terminal device during handover, so that the access network device can also determine the terminal device handover policy in a multicast communication scenario, thereby ensuring service continuity during handover of the terminal device, and finally improving the technical effect of communication efficiency of the terminal device.

Therefore, in combination with the methods shown in S1701-S1704a/S1704b and S1801-S1804a/S1804b, the first access network device serves as an execution subject, and in the process of the terminal device switching from the first access network device to the second access network device, the switching request acknowledgement information sent by the second access network device to the first access network device includes the second mapping relationship and the second sequence number, or includes the second mapping relationship and the second PDCP sequence number, so that the interaction of the sequence numbers of the MBS data packets between the two base stations is realized, the first access network device can determine the transmission progress of the MBS data packets of the second access network device, so that the first access network device can compare the sequence number of the MBS data packet to be sent with the sequence number of the MBS data packet to be sent by the second access network device according to the first access network device itself, and determining that the terminal device uses conventional handover or DAPS handover when switching from the first access network device to the second access network device in a multicast scenario, thereby ensuring that the terminal device can use DAPS handover to ensure the continuity of MBS service data received by the terminal device when switching the base station, especially when the progress of transmitting MBS data packets by the second access network device is faster and the progress of transmitting MBS data packets by the first access network device is slower, so that for the difference in progress of transmitting data packets between the first access network device and the second access network device, the first access network device can determine a corresponding handover policy to avoid service interruption of the terminal device in the handover process, thereby enabling the access network device in the multicast communication scenario to also determine the handover policy of the terminal device, further ensuring the service continuity when switching the terminal device, and improving the communication quality of the terminal device in the handover process, and finally, the communication efficiency and the user experience of the terminal equipment are improved.

Steps S1805 to S1817 in the second part of fig. 18 may refer to the descriptions in S1406 to S1418 in fig. 14, and the specific implementation, principle and technical effect are the same, and are not described again.

Further, in the procedure of performing DAPS handover by the terminal device shown in fig. 12, 14, 16, and 18, based on that the terminal device simultaneously maintains connection with the first access network device and the second access network device in the handover procedure, the terminal device may receive the MBS data packet multicast by the first access network device and the MBS data packet multicast by the second access network device, however, the scenario of switching the terminal device from the first access network device to the second access network device is more, for example, the terminal device moves and the network signal of the first access network device is not good, which may cause the terminal device to disconnect the connection relationship with the first access network device before receiving the MBS data packet with the sequence number SN4-SN3 sent by the first access network device in a multicast manner in the procedure of DAPS handover, resulting in that the terminal device cannot continue to perform DAPS handover and still cause interruption of the MBS data packet received by the terminal device.

Therefore, on the basis of the embodiments shown in fig. 12, 14, 16, and 18, after the first access network device sends the MBS data packet before SN3 to the terminal device, when it is determined that the first access network device is disconnected from the terminal device, the first access network device sends all MBS data packets with the fifth sequence numbers SN5-SN3 of the fifth data packet to the second access network device, where the fifth data packet is the first data packet to be sent by the first access network device after the first access network device is disconnected from the terminal device, and SN4 is greater than or equal to SN5 and is less than SN3. And then, the second access network equipment sends the SN5-SN3 which is supposed to be sent to the terminal equipment by the first access network equipment in a multicast mode to the terminal equipment.

Optionally, in order to determine whether the connection between the terminal device and the first access network device is disconnected, the embodiment of the present application provides the following three ways:

in the first method, after the terminal device completes the handover in S408, a Timer is started, which is recorded as Timer1, and if after that, until the Timer1 times out, no MBS data packet sent by the first access network device in a multicast mode is received, it is determined that the connection between the terminal device and the first access network device has been disconnected, and at this time, the terminal device may send, to the second access network device accessed at this time, a fifth sequence number SN5 of a next fifth data packet to be received by the terminal device, or a PDCP sequence number PDCP SN5 of the fifth data packet. And then, the second access network equipment requests the first access network equipment for an MBS data packet of SN5-SN3, and finally, the second access network equipment sends the SN5-SN3 which is sent to the terminal equipment by the first access network equipment in a multicast mode to the terminal equipment.

In a second mode, after a first access network device sends a MBS data packet to a terminal device in a multicast mode, a Timer is started and recorded as Timer2, if after sending a certain MBS data packet, no ACK or NACK feedback of the terminal device to the MBS data packet is received until the Timer2 times out, it is determined that the connection between the terminal device and the first access network device has been disconnected, at this time, the local access network device may send, to the second access network device, a sequence number or PDCP sequence number of the last data packet that is received by the first access network device and fed back by the terminal device, send, to the second access network device, the MBS data packet that is not sent to the terminal device and is SN5-SN3, and finally, the second access network device sends, to the terminal device, SN5-SN3 that should be sent to the terminal device by the first access network device in a multicast mode.

And in a third mode, after the first access network equipment indicates the terminal equipment to feed back the RLC status report, starting a Timer, and recording the Timer as Timer3, if the RLC status report reported by the terminal equipment is not received when the Timer3 times out, determining that the connection between the terminal equipment and the first access network equipment is disconnected, at the moment, the first access network equipment can send the serial number or the PDCP serial number of the last data packet fed back by the terminal equipment to the second access network equipment, and send the MBS data packet of SN5-SN3 which is not sent to the terminal equipment to the second access network equipment, and finally, the second access network equipment sends the SN5-SN3 which is supposed to be sent to the terminal equipment by the first access network equipment in a multicast mode to the terminal equipment in a unicast mode.

Therefore, in the procedure of performing DAPS handover by the terminal device, even if the terminal device disconnects from the first access network device, the present embodiment can actively determine that the connection is disconnected, and the first access network device forwards the MBS data packet that should be sent in a multicast manner but has not yet been sent to the second access network device, and the second access network device sends the MBS data packet to the terminal device in a unicast manner.

Accordingly, for the terminal device in this embodiment, during the DAPS handover, the following three types of data are received: therefore, for the terminal device in the embodiment shown in fig. 12 and 16, when the terminal device sequentially sequences the MBS data packets and delivers them to the upper layer, in S1217, the PDCP layer of the terminal device may sequentially deliver the MBS data packets received from the first access network device and sent in a multicast manner to the upper layer, and then sequentially deliver the MBS data packets received from the second access network device and sent in a unicast manner to the upper layer, and the last MBS data packet sent in a second access network device may include the end identification information, and finally sequentially deliver the MBS data packets received from the second access network device and sent in a multicast manner to the upper layer. In addition, for the terminal device in the embodiments shown in fig. 14 and fig. 18, since the PDCP sequence numbers of the MBS data packets that the second access network device sequentially sends in the unicast manner and in the multicast manner are known, the terminal device may still sequence the received MBS data packets according to the third mapping relationship.

Optionally, an embodiment of the present application further provides a communication method, which is applied to the first access network device in the embodiments shown in fig. 11 to fig. 18, so that the first access network device can first determine the second access network device to which the terminal device accesses before sending the handover request of the terminal device to the second access network device.

Specifically, in this embodiment, the first access network device determines, according to subscription information of the terminal device, the second access network device to which the terminal device is to be handed over, where the subscription information is used to indicate multicast service information that is being received or is interested in being received by the terminal device, and the multicast service information includes MBS service information.

After the terminal device accesses the first access network device, the terminal device may send multicast service information that the terminal device is interested in receiving to the first access network device, where a specific quantization form may be an interest value of different multicast services, and when the interest value is higher, it indicates that the terminal device is more interested in the multicast service. For example, the terminal device sends "multicast service a-0.6" and "multicast service B-0.4" to the first access network device, which correspond to the interest value of 0.6 for multicast service a and the interest value of 0.4 for multicast service B. Alternatively, it may also be defined by using priorities (e.g. high, medium, low), where a higher priority indicates that the terminal device is more interested in multicast services. Or, a common priority may be set for different multicast services, and a field may be added to each MBS service message to indicate the priority of the multicast service.

Exemplarily, when the first access network device determines that the terminal device is to be switched, if the access network device 1 provides a multicast service a and a multicast service B, and the access network device 2 provides only one of the multicast services, the first access network device determines that the access network device 1 is the second access network device; or, if the access network device 1 provides the multicast service a or the multicast service B, and the access network device 2 does not provide the multicast services a and B, the first access network device determines that the access network device 1 is the second access network device; or, if the access network device 1 provides the multicast service a and the access network device 2 provides the multicast service B, the first access network device determines that the access network device 1 is the second access network device because the interest value of the terminal device to the multicast service a is 0.6 and is greater than the interest value to the multicast service B by 0.4.

Optionally, when the first access network device determines the second access network device according to the interest value of the terminal device, a threshold may be further set to determine whether to consider a service that the terminal device is interested in, for example, the threshold is set to 0.4, when the first access network device determines that the terminal device is to be switched, if the access network device 1 provides the multicast service a but the measured communication quality is low, and the access network device 2 does not provide the multicast services a and B but the measured communication quality is high; at this time, the interest value of the terminal device for the multicast service a needs to be combined, and if the interest value is 0.3 and is smaller than the threshold, it indicates that the interest of the terminal device for the multicast service a is not high, and the access network device 2 may be used as the second access network device on the premise of the communication quality; if the interest value is 0.7 and is greater than the threshold value, it indicates that the terminal device has a high interest in the multicast service a, and in order to ensure that the terminal device receives the multicast service a, the access network device 2 is used as the second access network device.

It should be noted that, when determining the second access network device, the first access network device may also comprehensively consider information such as cell quality, whether the second access network device supports the multicast service being received by the terminal device, and the like, which is the same as that in the prior art and is not described again.

In summary, in the communication method provided in this embodiment, in the switching process of the terminal device, the first access network device determines the second access network device according to the interest value of the terminal device for the multicast service, so that the multicast service with a higher interest value of the terminal device or the multicast service being received can be provided by the second access network device after switching, thereby maximally ensuring the continuity of receiving multicast service data during switching of the terminal device, so that the multicast service data is not interrupted during switching because the switched second access network device does not support, and further ensuring the communication efficiency of the terminal device.

In the foregoing embodiments, the communication method provided in the embodiments of the present application is described, and in order to implement each function in the communication method provided in the embodiments of the present application, the first access network device, the second access network device, and the terminal device that are execution subjects may include a hardware structure and/or a software module, and each function is implemented in the form of a hardware structure, a software module, or a hardware structure and a software module. Whether any of the above-described functions is implemented as a hardware structure, a software module, or a hardware structure plus a software module depends upon the particular application and design constraints imposed on the technical solution.

For example, fig. 19 is a schematic structural diagram of a first embodiment of a communication device 190 provided in the present application, where the communication device 190 includes: a processing unit 1901 and a communication unit 1902.

When the communication apparatus shown in fig. 19 is used as the second access network device, the processing unit 1901 is configured to determine a first sequence number and a second sequence number; the first sequence number is a sequence number of a first data packet, the first data packet is a first data packet to be sent by first access network equipment, the second sequence number is a sequence number of a second data packet, and the second data packet is a first data packet to be sent by second access network equipment; the processing unit 1901 is further configured to determine a handover policy of the terminal device according to the first sequence number and the second sequence number; the first access network device is a source base station of the terminal device, the second access network device is a target base station of the terminal device, and the first sequence number and the second sequence number correspond to the first service.

Optionally, the processing unit 1901 is specifically configured to, when the first sequence number is smaller than the second sequence number, determine that the handover policy of the terminal device is DAPS handover; and/or when the first serial number is larger than the second serial number, determining that the switching strategy of the terminal equipment is non-DAPS switching; and/or when the first sequence number is equal to the second sequence number, determining that the switching strategy of the terminal equipment is DAPS switching or non-DAPS switching.

Optionally, the communication unit 1902 is configured to send, to the first access network device, indication information, where the indication information is used to indicate a handover policy.

Optionally, the communication unit 1902 is further configured to receive a first sequence number from the first access network device; or receiving a first mapping relation and a first sequence number from the first access network device, wherein the first mapping relation is used for indicating a corresponding relation between the sequence number of the data packet sent by the first access network device and the PDCP sequence number of the data packet sent by the first access network device; or, receiving a first mapping relation and a first PDCP sequence number from the first access network device, where the first PDCP sequence number is a PDCP sequence number of the first data packet.

Optionally, the communication unit 1902 is further configured to send, to the first access network device, a third sequence number and/or a third PDCP sequence number, where the third sequence number is a sequence number of a third data packet, the third data packet is a first data packet to be sent by the second access network device, and the third PDCP sequence number is a PDCP sequence number of the third data packet.

Optionally, the communication unit 1902 is further configured to receive end indication information from the first access network device, where the end indication information is used to indicate that the first access network device has completed data transmission to the terminal device.

Optionally, the communication unit 1902 is further configured to send the second mapping relationship and/or the third mapping relationship to the first access network device; the second mapping relation is used for indicating the corresponding relation between the sequence number of the data packet sent by the second access network device and the PDCP sequence number of the data packet sent by the second access network device, and the third mapping relation is used for indicating the corresponding relation between the PDCP sequence number of the data packet sent by the first access network device and the PDCP sequence number of the data packet sent by the second access network device.

When the communication apparatus shown in fig. 19 serves as a first access network device, the communication unit 1902 is configured to send a first sequence number to a second access network device; or, sending the first sequence number and the first mapping relation to the second access network device; or, the first PDCP sequence number and the first mapping relationship are sent to the second access network device; the communication unit 1902 is further configured to receive indication information from the second access network device, where the indication information is used to indicate a handover policy of the terminal device; the first sequence number is a sequence number of a first data packet, the first data packet is a first data packet to be sent by first access network equipment, a first mapping relation is used for indicating a corresponding relation between the sequence number of the data packet sent by the first access network equipment and a PDCP (packet data convergence protocol) sequence number of the data packet sent by the first access network equipment, the first PDCP sequence number is the PDCP sequence number of the first data packet, the first access network equipment is a source base station of terminal equipment, the second access network equipment is a target base station of the terminal equipment, and the first sequence number corresponds to a first service.

Optionally, the communication unit 1902 is further configured to receive a second mapping relationship and/or a third mapping relationship sent by a second access network device; the second mapping relation is used for indicating a corresponding relation between a sequence number of a data packet sent by the second access network device and a PDCP sequence number of the data packet sent by the second access network device, and the third mapping relation is used for indicating a corresponding relation between a PDCP sequence number of the data packet sent by the first access network device and a PDCP sequence number of the data packet sent by the second access network device.

Optionally, the communication unit 1902 is further configured to send the third mapping relationship to the terminal.

Optionally, the communication unit 1902 is further configured to receive a third sequence number and/or a third PDCP sequence number from the second access network device, where the third sequence number is a sequence number of a third data packet, the third data packet is a first data packet to be sent by the second access network device, and the third PDCP sequence number is a PDCP sequence number of the third data packet.

Optionally, the communication unit 1902 is further configured to send end instruction information to the terminal device; and/or sending ending indication information to the second access network equipment;

optionally, the processing unit 1901 is configured to determine, according to subscription information from the terminal device, the second access network device, where the subscription information is used to indicate multicast service information that the terminal device is receiving or is interested in receiving.

When the communication apparatus shown in fig. 19 serves as the second access network device, the processing unit 1901 is configured to determine a first sequence number and a second sequence number; the first sequence number is a sequence number of a first data packet, the first data packet is a first data packet to be sent by first access network equipment, the second sequence number is a sequence number of a second data packet, and the second data packet is a first data packet to be sent by second access network equipment; the processing unit 1901 is further configured to determine a handover policy of the terminal device according to a first sequence number and a second sequence number, where the first access network device is a source base station of the terminal device, the second access network device is a target base station of the terminal device, and the first sequence number and the second sequence number correspond to the first service.

Optionally, the processing unit 1901 is specifically configured to, when the first sequence number is smaller than the second sequence number, determine that the handover policy of the terminal device is DAPS handover; and/or when the first sequence number is larger than the second sequence number, determining that the switching strategy of the terminal equipment is non-DAPS switching; and/or when the first sequence number is equal to the second sequence number, determining that the handover strategy of the terminal equipment is DAPS handover or non-DAPS handover.

Optionally, the communication unit 1902 is configured to receive a second sequence number from the second access network device; or receiving a second mapping relation and a second sequence number from the second access network device, where the second mapping relation is used to indicate a correspondence between a sequence number of a data packet sent by the second access network device and a PDCP sequence number of the data packet sent by the second access network device; or receiving a second mapping relation and a second PDCP sequence number sent by the second access network device, where the second PDCP sequence number is a PDCP sequence number of the second packet.

Optionally, the communication unit 1902 is further configured to send end indication information to the second access network device; and/or sending ending indication information to the terminal equipment;

optionally, the communication unit 1902 is further configured to send the third mapping relationship to the terminal device; the third mapping relationship is used for indicating a corresponding relationship between the PDCP sequence number of the data packet sent by the first access network device and the PDCP sequence number of the data packet sent by the second access network device.

Optionally, the processing unit 1901 is further configured to determine the second access network device according to subscription information of the terminal device, where the subscription information is used to indicate multicast service information that the terminal device is receiving or interested in receiving.

When the communication apparatus shown in fig. 19 serves as a first access network device, the communication unit 1902 is configured to receive a handover request from the first access network device; the communication unit 1902 is further configured to send the second sequence number to the first access network device; or, sending the second sequence number and the second mapping relation to the first access network device; or, sending the second PDCP sequence number and the second mapping relationship to the first access network device; the second sequence number is a sequence number of a second data packet, the second data packet is a first data packet to be sent by second access network equipment, the second mapping relation is used for indicating a corresponding relation between the sequence number of the data packet sent by the second access network equipment and a PDCP (packet data convergence protocol) sequence number of the data packet sent by the second access network equipment, the second PDCP sequence number is the PDCP sequence number of the second data packet, the first access network equipment is a source base station of the terminal equipment, the second access network equipment is a target base station of the terminal equipment, and the second sequence number corresponds to the first service.

Optionally, the communication unit 1902 is further configured to send, to the first access network device, a third sequence number and/or a third PDCP sequence number, where the third sequence number is a sequence number of a third data packet, the third data packet is a sequence number of a data packet to be sent by the second access network device, and the third PDCP sequence number is a PDCP sequence number of the third data packet.

Optionally, the communication unit 1902 is further configured to receive end indication information from the first access network device, where the end indication information indicates that the first access network device has completed data transmission to the terminal device.

When the communication apparatus shown in fig. 19 is used as a terminal device, the communication unit 1902 is configured to receive at least one data packet from a first access network device and at least one data packet from a second access network device; the processing unit 1901 is configured to, in order, deliver at least one data packet from the first access network device to an upper layer by the PDCP layer; the communication unit 1902 is further configured to receive end indication information from the first access network device, where the end indication information indicates that the first access network device has completed data transmission to the terminal device; the processing unit 1901 is further configured to, in order, deliver at least one data packet from the second access network device to an upper layer by the PDCP layer.

Optionally, the processing unit 1901 is further configured to determine that in-order delivery of the data packet from the first access network device to the upper layer is completed.

Optionally, the communication unit 1902 is further configured to send subscription information of the terminal device to the first access network device, where the subscription information is used to indicate multicast service information that the terminal device is receiving or interested in receiving.

When the communication apparatus shown in fig. 19 is used as a terminal device, the communication unit 1902 is configured to receive a third mapping relationship from a first access network device; the third mapping relation is used for representing the corresponding relation between the PDCP serial number of the first access network equipment and the PDCP serial number of the second access network equipment; the communication unit is configured to reorder, according to the third mapping relationship, the data packet sent from the first access network device and the data packet sent from the second access network device.

Optionally, the processing unit 1901 is further configured to map, according to the third mapping relationship, a PDCP sequence number of a data packet from the first access network device to a PDCP sequence number of a data packet of the second access network device; or mapping the PDCP sequence number of the data packet from the second access network equipment into the PDCP sequence number of the data packet of the first access network equipment according to the third mapping relation;

It should be noted that the division of the modules of the above apparatus is only a logical division, and the actual implementation may be wholly or partially integrated into one physical entity, or may be physically separated. And these modules can be realized in the form of software called by processing element; or can be implemented in the form of hardware; and part of the modules can be realized in the form of calling software by the processing element, and part of the modules can be realized in the form of hardware. For example, the determining module may be a processing element separately set up, or may be implemented by being integrated in a chip of the apparatus, or may be stored in a memory of the apparatus in the form of program code, and the function of the determining module is called and executed by a processing element of the apparatus. Other modules are implemented similarly. In addition, all or part of the modules can be integrated together or can be independently realized. The processing element described herein may be an integrated circuit having signal processing capabilities. In implementation, each step of the above method or each module above may be implemented by an integrated logic circuit of hardware in a processor element or an instruction in the form of software.

For example, the above modules may be one or more integrated circuits configured to implement the above methods, such as: one or more Application Specific Integrated Circuits (ASICs), or one or more microprocessors (DSPs), or one or more Field Programmable Gate Arrays (FPGAs), among others. For another example, when some of the above modules are implemented in the form of a processing element scheduler code, the processing element may be a general-purpose processor, such as a Central Processing Unit (CPU) or other processor capable of calling program code. As another example, these modules may be integrated together, implemented in the form of a system-on-a-chip (SOC).

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. The procedures or functions described in accordance with the embodiments of the application are all or partially generated when the computer program instructions are loaded and executed on a computer. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, from one website site, computer, server, or data center to another website site, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that includes one or more available media. The usable medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a Solid State Disk (SSD)), among others.

Fig. 20 is a schematic structural diagram of a second embodiment of a communication apparatus provided in this application, where the communication apparatus may be used as the first access network device, the second access network device, or the terminal device in any of the foregoing embodiments of the application. As shown in fig. 20, the communication apparatus 1100 may include: a processor 111 (e.g., CPU), transceiver 113; the transceiver 113 is coupled to the processor 111, and the processor 111 controls the transceiver 113 to transmit and receive. Optionally, the communication apparatus 1100 further includes a memory 112, where the memory 112 may store various instructions for performing various processing functions and implementing the method steps executed by the network device, the terminal device, or the core network device in this embodiment.

Optionally, the communication apparatus according to the embodiment of the present application may further include: a power supply 114, a system bus 115, and a communication interface 116. The transceiver 113 may be integrated in a transceiver of the communication device or may be a separate transceiving antenna on the communication device. The system bus 115 is used to implement communication connections between the elements. The communication interface 116 is used for implementing connection communication between the communication device and other peripheral devices.

In this embodiment, the processor 111 is configured to be coupled to the memory 112, and read and execute instructions in the memory 112, so as to implement the method steps performed by the network device, the terminal device, or the core network device in the foregoing method embodiments. The transceiver 113 is coupled to the processor 111, and the processor 111 controls the transceiver 113 to perform message transceiving, which is similar in implementation principle and technical effect and will not be described in detail herein.

The system bus mentioned in fig. 20 may be a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, or the like. The system bus may be divided into an address bus, a data bus, a control bus, and the like. For ease of illustration, only one thick line is shown, but this does not mean that there is only one bus or one type of bus. The communication interface is used for realizing communication between the database access device and other equipment (such as a client, a read-write library and a read-only library). The memory may comprise RAM, and may also include non-volatile memory (non-volatile memory), such as at least one disk memory.

The processor mentioned in this fig. 20 may be a general-purpose processor including a central processing unit CPU, a Network Processor (NP), and the like; but also a digital signal processor DSP, an application specific integrated circuit ASIC, a field programmable gate array FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components.

Optionally, an embodiment of the present application further provides a readable storage medium, where instructions are stored in the storage medium, and when the instructions are executed on a computer, the computer executes the method performed by the first access network device, the second access network device, or the terminal device in fig. 8 to 18.

Optionally, an embodiment of the present application further provides a chip for executing the instructions, where the chip is configured to execute the method performed by the first access network device, the second access network device, or the terminal device in fig. 8 to fig. 18.

An embodiment of the present application further provides a program product, where the program product includes a computer program, where the computer program is stored in a storage medium, and the computer program can be read by at least one processor from the storage medium, and the at least one processor, when executing the computer program, can implement the method performed by the first access network device, the second access network device, or the terminal device in fig. 8 to 18.

In the embodiments of the present application, "at least one" means one or more, "a plurality" means two or more. "and/or" describes the association relationship of the associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone, wherein A and B can be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship; in the formula, the character "/" indicates that the preceding and following related objects are in a relationship of "division". "at least one of the following" or similar expressions refer to any combination of these items, including any combination of the singular or plural items. For example, at least one (one) of a, b, or c, may represent: a, b, c, a-b, a-c, b-c, or a-b-c, wherein a, b, c may be single or multiple.

It is to be understood that the various numerical references referred to in the embodiments of the present application are only for descriptive convenience and are not intended to limit the scope of the embodiments of the present application.

It should be understood that, in the embodiment of the present invention, the sequence numbers of the above-mentioned processes do not mean the execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiment of the present application.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A communication method, adapted to a second access network device, comprising:

determining a first sequence number and a second sequence number; the first sequence number is a sequence number of a first data packet, the first data packet is a first data packet to be sent by first access network equipment, the second sequence number is a sequence number of a second data packet, and the second data packet is a first data packet to be sent by second access network equipment;

Determining a switching strategy of the terminal equipment according to the first serial number and the second serial number; the first access network device is a source base station of the terminal device, the second access network device is a target base station of the terminal device, and the first sequence number and the second sequence number correspond to a first service;

the determining a handover policy of the terminal device according to the first sequence number and the second sequence number includes: and when the first serial number is smaller than the second serial number, determining that the switching strategy of the terminal equipment is DAPS switching.

2. The method of claim 1, wherein determining the handover policy of the terminal device according to the first sequence number and the second sequence number further comprises:

when the first sequence number is larger than the second sequence number, determining that the switching strategy of the terminal equipment is non-DAPS switching; and/or the presence of a gas in the atmosphere,

and when the first sequence number is equal to the second sequence number, determining that the switching strategy of the terminal equipment is DAPS switching or non-DAPS switching.

3. The method of claim 1 or 2, further comprising:

and sending indication information to the first access network equipment, wherein the indication information is used for indicating the switching strategy.

4. The method according to claim 1 or 2, characterized in that the method further comprises:

receiving the first sequence number from the first access network device; or,

receiving a first mapping relation and the first sequence number from the first access network device, wherein the first mapping relation is used for indicating a corresponding relation between a sequence number of a data packet sent by the first access network device and a PDCP sequence number of the data packet sent by the first access network device; or,

receiving the first mapping relation and a first PDCP sequence number from the first access network equipment, wherein the first PDCP sequence number is the PDCP sequence number of the first data packet.

5. The method according to claim 1 or 2, characterized in that the method further comprises:

and sending a third sequence number and/or a third PDCP sequence number to the first access network device, where the third sequence number is a sequence number of a third packet, the third packet is a first packet to be sent by the second access network device, and the third PDCP sequence number is a PDCP sequence number of the third packet.

6. The method of claim 1 or 2, further comprising:

And receiving end indication information from the first access network equipment, wherein the end indication information is used for indicating that the first access network equipment finishes data transmission to the terminal equipment.

7. The method of claim 1 or 2, wherein after receiving the first mapping from the first access network device, the method further comprises:

sending a second mapping relation and/or a third mapping relation to the first access network device;

the second mapping relationship is used for indicating a corresponding relationship between a sequence number of a data packet sent by the second access network device and a PDCP sequence number of the data packet sent by the second access network device, and the third mapping relationship is used for indicating a corresponding relationship between a PDCP sequence number of a data packet sent by the first access network device and a PDCP sequence number of a data packet sent by the second access network device.

8. A communication method, adapted to a first access network device, comprising:

sending the first sequence number to the second access network equipment; or, the first sequence number and the first mapping relationship are sent to the second access network device; or, sending a first PDCP sequence number and a first mapping relationship to the second access network device;

Receiving indication information from the second access network equipment, wherein the indication information is used for indicating a switching strategy of terminal equipment; the switching strategy is determined by the second access network equipment according to the first sequence number and the second sequence number; the first sequence number is a sequence number of a first data packet, the first data packet is a first data packet to be sent by the first access network device, the second sequence number is a sequence number of a second data packet, and the second data packet is a first data packet to be sent by the second access network device; the first mapping relationship is used for indicating a corresponding relationship between a sequence number of a data packet sent by the first access network device and a PDCP sequence number of the data packet sent by the first access network device, where the first PDCP sequence number is the PDCP sequence number of the first data packet, the first access network device is a source base station of the terminal device, the second access network device is a target base station of the terminal device, and the first sequence number and the second sequence number correspond to a first service;

the second access network device determines a handover policy of the terminal device according to the first sequence number and the second sequence number, including: and when the first sequence number is smaller than the second sequence number, the second access network equipment determines that the switching strategy of the terminal equipment is DAPS switching.

9. The method of claim 8, wherein after sending the first mapping relationship to the second access network device, the method further comprises:

receiving a second mapping relation and/or a third mapping relation sent by the second access network equipment;

10. The method of claim 9, wherein after sending the first mapping relationship to the second access network device, the method further comprises:

and sending the third mapping relation to the terminal.

11. The method according to any one of claims 8-10, further comprising:

and receiving a third sequence number and/or a third PDCP sequence number from the second access network device, where the third sequence number is a sequence number of a third packet, the third packet is a first packet to be sent by the second access network device, and the third PDCP sequence number is a PDCP sequence number of the third packet.

12. The method of any one of claims 8-10, further comprising:

sending ending indication information to the terminal equipment; and/or the presence of a gas in the gas,

sending end indication information to the second access network equipment;

wherein the end indication information indicates that the first access network device has completed data transmission to the terminal device.

13. The method according to any one of claims 8-10, comprising:

and determining the second access network equipment according to subscription information from the terminal equipment, wherein the subscription information is used for indicating the multicast service information which is received or is interested in being received by the terminal equipment.

14. A communication method, adapted for a first access network device, comprising:

determining a first sequence number and a second sequence number; the first sequence number is a sequence number of a first data packet, the first data packet is a first data packet to be sent by the first access network device, the second sequence number is a sequence number of a second data packet, and the second data packet is a first data packet to be sent by the second access network device;

determining a handover strategy of a terminal device according to the first sequence number and the second sequence number, wherein the first access network device is a source base station of the terminal device, the second access network device is a target base station of the terminal device, and the first sequence number and the second sequence number correspond to a first service;

The determining a handover policy of the terminal device according to the first sequence number and the second sequence number includes:

and when the first sequence number is smaller than the second sequence number, determining that the switching strategy of the terminal equipment is DAPS switching.

15. The method of claim 14, wherein determining the handover policy of the terminal device according to the first sequence number and the second sequence number further comprises:

when the first sequence number is larger than the second sequence number, determining that the switching strategy of the terminal equipment is non-DAPS switching; and/or the presence of a gas in the gas,

16. The method of claim 14 or 15, further comprising:

receiving a second sequence number from the second access network device; or,

receiving a second mapping relation and the second sequence number from the second access network device, where the second mapping relation is used to indicate a correspondence between a sequence number of a data packet sent by the second access network device and a PDCP sequence number of the data packet sent by the second access network device; or,

And receiving the second mapping relation and a second PDCP sequence number sent by the second access network device, where the second PDCP sequence number is a PDCP sequence number of the second data packet.

17. The method according to claim 14 or 15, characterized in that the method further comprises:

18. A communication method, adapted to a second access network device, comprising:

receiving a handover request from a first access network device;

sending a second sequence number to the first access network device; or, sending the second sequence number and the second mapping relationship to the first access network device; or, sending a second PDCP sequence number and the second mapping relationship to the first access network device;

determining a switching strategy of the terminal equipment according to the first serial number and the second serial number; the first sequence number is a sequence number of a first data packet, the first data packet is a first data packet to be sent by first access network equipment, the second sequence number is a sequence number of a second data packet, the second data packet is a first data packet to be sent by second access network equipment, the second mapping relationship is used for indicating a corresponding relationship between the sequence number of the data packet sent by the second access network equipment and a PDCP sequence number of the data packet sent by the second access network equipment, the second PDCP sequence number is a PDCP sequence number of the second data packet, the first access network equipment is a source base station of terminal equipment, the second access network equipment is a target base station of the terminal equipment, and the first sequence number and the second sequence number correspond to a first service;

The determining a handover policy of the terminal device according to the first sequence number and the second sequence number includes: and when the first sequence number is smaller than the second sequence number, determining that the switching strategy of the terminal equipment is DAPS switching.

19. The method of claim 18, further comprising:

and sending a third sequence number and/or a third PDCP sequence number to the first access network device, where the third sequence number is a sequence number of a third data packet, the third data packet is a sequence number of a data packet to be sent by the second access network device, and the third PDCP sequence number is a PDCP sequence number of the third data packet.

20. A communication method, wherein the method is applied to a terminal device, and comprises:

receiving an RRC connection reconfiguration message sent by first access network equipment, switching the RRC connection from the first access network equipment to second access network equipment, and executing a DAPS switching strategy; the DAPS switching strategy is determined by the second access network equipment according to the first sequence number and the second sequence number; the first sequence number is a sequence number of a first data packet, the first data packet is a first data packet to be sent by first access network equipment, the second sequence number is a sequence number of a second data packet, and the second data packet is a first data packet to be sent by second access network equipment; when the first serial number is smaller than the second serial number, the second access network equipment determines that the switching strategy of the terminal equipment is DAPS switching;

Wherein the executing the DAPS handover policy comprises:

receiving at least one data packet from a first access network device and at least one data packet from a second access network device;

the PDCP layer delivering the at least one data packet from the first access network device to an upper layer in sequence;

receiving end indication information from the first access network device, wherein the end indication information indicates that the first access network device has completed data transmission to the terminal device;

the PDCP layer delivers the at least one data packet from the second access network device to an upper layer in-order.

21. The method as claimed in claim 20, wherein before the PDCP layer delivers the data packets sent by the second access network device to the upper layer in sequence, the method further comprises:

determining that in-order delivery of the at least one data packet from the first access network device to an upper layer has been completed.

22. The method of claim 20 or 21, further comprising:

and sending subscription information of the terminal equipment to the first access network equipment, wherein the subscription information is used for indicating multicast service information which is being received or is interested in being received by the terminal equipment.

23. A communication method, wherein the method is applied to a terminal device, and comprises:

receiving an RRC connection reconfiguration message sent by first access network equipment, switching the RRC connection from the first access network equipment to second access network equipment, and executing a DAPS switching strategy; the RRC connection reconfiguration message comprises a third mapping relation; the third mapping relation is used for representing the corresponding relation between the PDCP serial number of the first access network equipment and the PDCP serial number of the second access network equipment;

reordering the data packets from the first access network device and the data packets from the second access network device according to the third mapping relationship;

the DAPS switching strategy is determined by the second access network equipment according to the first sequence number and the second sequence number; the first sequence number is a sequence number of a first data packet, the first data packet is a first data packet to be sent by first access network equipment, the second sequence number is a sequence number of a second data packet, and the second data packet is a first data packet to be sent by second access network equipment; and when the first sequence number is smaller than the second sequence number, the second access network equipment determines that the switching strategy of the terminal equipment is DAPS switching.

24. The method of claim 23, further comprising:

mapping the PDCP sequence number of the data packet from the first access network equipment to the PDCP sequence number of the data packet of the second access network equipment according to a third mapping relation; or,

and mapping the PDCP sequence number of the data packet from the second access network equipment to the PDCP sequence number of the data packet of the first access network equipment according to the third mapping relation.

25. The method of claim 23 or 24, further comprising:

26. A communications apparatus, comprising: a communication unit and a processing unit;

the communication unit is used for realizing the communication between the communication device and other devices;

the processing unit is for implementing the method according to any one of claims 1-7, 8-13, 14-17, 18-19, 20-22 or 23-25.

27. A communications apparatus, comprising: a processor and a communication interface;

The communication interface is used for realizing the communication between the communication device and other devices;

the processor is for implementing the method of any one of claims 1-7, any one of claims 8-13, any one of claims 14-17, any one of claims 18-19, any one of claims 20-22, or any one of claims 23-25.

28. A computer-readable storage medium, characterized in that it stores a computer program which, when executed by a processor, implements the method of any one of claims 1-7, 8-13, 14-17, 18-19, 20-22 or 23-25.