Communication method, access network device, terminal device and core network device

Abstract

Provided are a communication method, an access network device, a terminal device, and a core network device, which can switch the terminal device from a first access network device to a second access network device 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 obtain the first service progress of the first access network device according to the first serial number of the data packet forwarded by the first access network device, and extra progress interaction information does not need to be introduced between the two access network devices. The method comprises: the first access network device receiving a first data packet and first indication information from a core network device, the first indication information being used for indicating a sequence of the first data packet in at least one data packet; determining a first serial number of a first protocol layer of the first data packet according to the first indication information; and sending the first data packet to the terminal equipment.

Description

[0001] This application is a divisional application. The application number of the original application is 202010203782.4, and the original application date is March 20, 2020. The entire contents of the original application are incorporated into this application by reference. Technical Field

[0002] The present application relates to the field of communications, and more specifically, to a communication method, access network equipment, terminal equipment and core network equipment. Background Art

[0003] Multimedia Broadcast Multicast Service (MBMS) is a service for multiple terminal devices, such as live broadcast services and some public safety services. In the current communication system, between the access network equipment and the terminal equipment, the MBMS service can be sent to the terminal equipment in unicast transmission mode by establishing a dedicated bearer with a single terminal equipment, or it can be sent to the terminal equipment in multicast (groupcast) transmission mode by establishing a shared bearer with multiple terminal equipment. Regardless of the unicast transmission mode or the multicast transmission mode, different access network equipment will independently determine the sequence number of the MBMS service data packet when sending the MBMS service data packet to the terminal equipment within its coverage area.

[0004] When a terminal device moves from a source access network device to a target access network device, in order to continue receiving MBMS services, it is necessary to continue receiving the MBMS services originally received on the source access network device after switching to the target access network device. However, since the progress of the MBMS services sent by the two access network devices may be inconsistent, and the source access network device and the target access network device are independent of each other in determining the sequence number of the MBMS service data packet, the source access network device and the target access network device may have inconsistent understandings of the MBMS service data packet sequence number during the switching process of the terminal device, which may cause the terminal device to interrupt the reception of the MBMS service before and after the switching or receive redundant data packets, and the continuity of the MBMS service cannot be guaranteed. Summary of the invention

[0005] The present application provides a communication method, access network equipment, terminal equipment and core network equipment. The communication method avoids the situation in the prior art where, for a terminal equipment receiving MBMS services, when switching across access network equipment, the terminal equipment receives redundant data packets or service data is interrupted due to inconsistent progress of multicast services of different access network equipment.

[0006] In a first aspect, a communication method is provided, the method being applied to a first access network device, and comprising:

[0007] Receive a first data packet and first indication information from a core network device, where the first indication information is used to indicate the order of the first data packet in at least one data packet; determine a first sequence number of a first protocol layer of the first data packet based on the first indication information; and send the first data packet to a terminal device.

[0008] Therefore, in the process of the terminal device switching from the first access network device to the second access network device, the second access network device can obtain the first service progress of the first access network device based on the sequence number of the data packet forwarded by the first access network device, without introducing additional progress interaction information between the two access network devices.

[0009] In combination with the first aspect, in certain implementations of the first aspect, the first indication information includes at least one of the following information: a General Packet Radio Service Tunneling Protocol-User Plane GTP-U sequence number, a first service sequence number; the first service sequence number is set by the core network device or the data server, the first data packet is a data packet of the first service, and the at least one data packet is a data packet of the first service.

[0010] In combination with the first aspect, in certain implementations of the first aspect, the first protocol layer includes at least one of the following: a service data adaptation protocol SDAP layer, a packet data convergence protocol PDCP layer, and a radio link control layer protocol RLC layer.

[0011] In combination with the first aspect, in some implementations of the first aspect, the method also includes: when any of the following situations occurs: when the first protocol entity is newly created, the first protocol entity is rebuilt, and the first protocol entity is restored, setting the starting sequence number of the first protocol layer of the first data packet according to the first indication information.

[0012] Therefore, when any of the situations occurs during the creation of the first protocol entity of the first access network device, the starting sequence number of the first protocol layer of the first data packet is set according to the first indication information to ensure the continuity of the first business data packet and prevent the first business data packet from being discontinued due to the setting of the starting sequence number of the first protocol layer.

[0013] In combination with the first aspect, in certain implementations of the first aspect, the method further includes: sending second indication information to the terminal device, the second indication information being used to indicate the sequence number of the first data packet belonging to the first service sent by the first access network device to the terminal device after the first protocol entity is newly established or the first protocol entity is rebuilt or the first protocol entity is restored.

[0014] Therefore, the terminal device can determine the starting sequence number of the first protocol layer of the first received data packet according to the second indication information, thereby preventing data packet loss caused by inconsistent determination of the first data packet by the first terminal device and the first access network device.

[0015] In combination with the first aspect, in some implementations of the first aspect, the method also includes: receiving third indication information from a second access network device, the third indication information being used to instruct the first access network device to stop forwarding data packets to the second access network device; and stopping forwarding data packets to the second access network device according to the third indication information.

[0016] Therefore, during the switching process of the first terminal device, the second access network device determines whether the data forwarding of the first access network device can be stopped, and sends data forwarding stop indication information to the first access network device, thereby ensuring the continuity of the terminal device receiving multicast services during the switching process and avoiding packet loss or redundant transmission.

[0017] In combination with the first aspect, in certain implementations of the first aspect, the method further includes: receiving fourth indication information sent by the second access network device, the fourth indication information being used to indicate the sequence number of the first data packet forwarded by the first access network device to the second access network device; and forwarding the data packet to the second access network device according to the fourth indication information.

[0018] The fourth indication information indicates the first protocol layer sequence number of the first data packet not received by the first terminal device, that is, the starting data packet for data forwarding by the first access network device. This can avoid the first terminal device receiving redundant data packets, that is, although the data packet sent by the first access network device is successfully received by the first terminal device, it is still forwarded by the first access network device to the second access network device, and then sent to the first terminal device by the second access network device.

[0019] In combination with the first aspect, in certain implementations of the first aspect, the method further includes: receiving fifth indication information sent by a second access network device, the fifth indication information including a second sequence number N, the second sequence number being used to indicate the sequence number of the first data packet belonging to the first service sent by the second access network device to the terminal device after the terminal device is switched, and when the protocol layer sequence number corresponding to the data packet successfully sent by the first access network device to the terminal device is N-1, the first access network device stops sending data packets to the terminal device.

[0020] Therefore, during the switching process, the first access network device decides when to stop the connection of the terminal device according to the SN indicated by the second access network device, thereby ensuring the continuity of the terminal device receiving multicast services during the switching process and avoiding packet loss or redundant transmission.

[0021] In combination with the first aspect, in some implementations of the first aspect, the first access network device sends a stop indication message to the second access network device, instructing the first access network device to disconnect from the first terminal device.

[0022] In combination with the first aspect, in certain implementations of the first aspect, the second access network device sends fifth indication information to the first access network device, and the fifth indication information includes a second sequence number N-1. The second sequence number is used to indicate that when the first protocol layer sequence number of the data packet successfully sent by the first access network device to the terminal device is N-1, the first access network device stops sending data packets to the terminal device.

[0023] Therefore, the first access network device does not need to perform calculations again, and can stop sending the data packet directly when it reaches the first sequence number N-1.

[0024] According to a second aspect, a communication method is provided, which is applied to a terminal device and comprises: receiving second indication information from a first access network device, wherein the second indication information is used to indicate the sequence number of the first data packet belonging to the first service sent by the first access network device to the terminal device after the first protocol entity is newly established or the first protocol entity is rebuilt or the first protocol entity is restored.

[0025] In combination with the second aspect, in some implementations of the second aspect, the method also includes: when the first protocol entity is rebuilt or restored, sending a request message to the first access network device, wherein the request message is used to request the first access network device to send the sequence number of the first data packet belonging to the first service sent by the first access network device to the terminal device after the first protocol entity is rebuilt or the first protocol entity is restored.

[0026] In combination with the second aspect, in certain implementations of the second aspect, the method further includes: sending status report information of a data packet to a second access network device, wherein the status report information of the data packet is used to indicate the second access network device, data packets successfully received and data packets not successfully received by the terminal device, wherein the terminal device is switched from the first access network device to the second access network device.

[0027] In a third aspect, a communication method is provided, the method being applied to a second access network device, comprising: receiving a first data packet and first indication information from a core network device, the first indication information being used to indicate an order of the first data packet in at least one data packet; determining a second sequence number of a first protocol layer of the first data packet according to the first indication information;

[0028] The first data packet is sent to the first terminal device.

[0029] In combination with the third aspect, in certain implementations of the third aspect, the first indication information includes at least one of the following information: a General Packet Radio Service Tunneling Protocol-User Plane GTP-U sequence number, a first service sequence number; the first service sequence number is set by the core network device or the data server, the first data packet is a data packet of the first service, and the at least one data packet is a data packet of the first service.

[0030] In combination with the third aspect, in some implementations of the third aspect, the first protocol layer includes at least one of the following:

[0031] Service Data Adaptation Protocol SDAP layer, Packet Data Convergence Protocol PDCP layer and Radio Link Control layer protocol RLC layer.

[0032] In combination with the third aspect, in certain implementations of the third aspect, the method also includes: when any of the following situations occurs: when the first protocol entity is newly created, the first protocol entity is rebuilt, and the first protocol entity is restored, setting the starting sequence number of the first protocol layer of the first data packet according to the first indication information.

[0033] In combination with the third aspect, in certain implementations of the third aspect, the method further includes: sending second indication information to the terminal device, the second indication information being used to indicate the sequence number of the first data packet belonging to the first service sent by the first access network device to the terminal device after the first protocol entity is newly established or the first protocol entity is rebuilt or the first protocol entity is restored.

[0034] In combination with the third aspect, in certain implementations of the third aspect, the method further includes: receiving a data packet from a first access network device, wherein a second terminal device in the first access network device is switched from the first access network device to the second access network device, the first terminal device and the second terminal device both perform the first service, and the data packet sent by the first access network device is a data packet of the first service; when the second sequence number of the first protocol layer of the data packet currently being sent to the first terminal device is equal to or greater than the first sequence number of the first protocol layer of the data packet sent by the first access network device, sending third indication information to the first access network device, the third indication information being used to instruct the first access network device to stop forwarding the data packet to the second access network device.

[0035] In combination with the third aspect, in certain implementations of the third aspect, the method further includes: receiving status report information of the data packet from the second terminal device, the status report information of the data packet being used to indicate the second access network device the data packets successfully received and the data packets not successfully received by the terminal device; and sending fourth indication information to the first access network device based on the status report information, the fourth indication information being used to indicate the sequence number of the first data packet forwarded by the first access network device to the second access network device.

[0036] In combination with the third aspect, in certain implementations of the third aspect, the method further includes: sending fifth indication information to the first access network device, the fifth indication information including a second sequence number N, the second sequence number being used to indicate the sequence number of the first data packet belonging to the first service sent by the second access network device to the second terminal device after the switching of the second terminal device is completed.

[0037] In a fourth aspect, a communication method is provided, which is applied to a core network device, comprising: receiving a first data packet sent by a data server; sending a second data packet and first indication information to a first access network device, wherein the first indication information is used to indicate the order of the second data packet in at least one data packet sent by the core network device; sending a third data packet and second indication information to a second access network device, wherein the first indication information is used to indicate the order of the third data packet in at least one data packet of the core network device, and the data of the second data packet and the data of the third data packet are the same as the data of the first data packet.

[0038] In combination with the fourth aspect, in certain implementations of the fourth aspect, the first indication information includes at least one of the following information: a General Packet Radio Service Tunneling Protocol-User Plane GTP-U sequence number, a first service sequence number; the first service sequence number is set by the core network device or the data server, the first data packet is a data packet of the first service, and the at least one data packet is a data packet of the first service.

[0039] In a fifth aspect, an access network device is provided, which may be a first access network device, a chip or module within the first access network device, or a chip or a system on chip, and the access network device comprises: a transceiver unit for receiving a first data packet and first indication information from a core network device, wherein the first indication information is used to indicate the order of the first data packet in at least one data packet; a processing unit for determining a first sequence number of a first protocol layer of the first data packet according to the first indication information; and the transceiver unit is further used to send the first data packet to a terminal device.

[0040] In combination with the fifth aspect, in certain implementations of the fifth aspect, the first indication information includes at least one of the following information: a General Packet Radio Service Tunneling Protocol-User Plane GTP-U sequence number, a first service sequence number; the first sequence number of the first service is set by the core network device or the data server, the first data packet is a data packet of the first service, and the at least one data packet is a data packet of the first service.

[0041] In combination with the fifth aspect, in certain implementations of the fifth aspect, the first protocol layer includes at least one of the following: a service data adaptation protocol SDAP layer, a packet data convergence protocol PDCP layer, and a radio link control layer protocol RLC layer.

[0042] In combination with the fifth aspect, in certain implementations of the fifth aspect, the processing unit is also used to: determine the starting sequence number of the first protocol layer of the first data packet according to the first indication information when any of the following situations occurs: the first protocol entity is newly created, the first protocol entity is rebuilt, and the first protocol entity is restored.

[0043] In combination with the fifth aspect, in certain implementations of the fifth aspect, the transceiver unit is also used to: send second indication information to the terminal device, the second indication information being used to indicate the sequence number of the first data packet belonging to the first service sent by the first access network device to the terminal device after the first protocol entity is newly established or the first protocol entity is rebuilt or the first protocol entity is restored.

[0044] In combination with the fifth aspect, in certain implementations of the fifth aspect, the transceiver unit is also used to: receive third indication information from a second access network device, the third indication information being used to instruct the first access network device to stop forwarding data packets to the second access network device; and the processing unit being used to stop forwarding data packets to the second access network device according to the third indication information.

[0045] In combination with the fifth aspect, in certain implementations of the fifth aspect, the transceiver unit is also used to: receive fourth indication information sent by the second access network device, the fourth indication information being used to indicate the sequence number of the first data packet forwarded by the first access network device to the second access network device; and the processing unit being used to forward the data packet to the second access network device according to the fourth indication information.

[0046] In combination with the fifth aspect, in certain implementations of the fifth aspect, the transceiver unit is also used to: receive fifth indication information sent by a second access network device, the fifth indication information including a second sequence number N, the second sequence number being used to indicate the sequence number of the first data packet belonging to the first service sent by the second access network device to the terminal device after the terminal device is switched, and the processing unit is used to determine that when the protocol layer sequence number corresponding to the data packet successfully sent by the first access network device to the terminal device is N-1, stop sending data packets to the terminal device.

[0047] In the sixth aspect, a terminal device is provided, which can be a terminal device, a chip or module in the terminal device, or a chip or a system on chip. The terminal device includes: a transceiver unit, used to receive second indication information sent by a first access network device, and the second indication information is used to indicate the sequence number of the first data packet belonging to the first service sent by the first access network device to the terminal device after the first protocol entity is newly established or the first protocol entity is rebuilt or the first protocol entity is restored.

[0048] In combination with the sixth aspect, in certain implementations of the sixth aspect, the transceiver unit is also used to: when the first protocol entity is rebuilt or restored, send a request message to the first access network device, and the request message is used to request the first access network device to send the sequence number of the first data packet belonging to the first service sent by the first access network device to the terminal device after the first protocol entity is rebuilt or the first protocol entity is restored.

[0049] In combination with the sixth aspect, in certain implementations of the sixth aspect, the transceiver unit is also used to: send status report information of the data packet to the second access network device, the status report information of the data packet is used to indicate the second access network device, the data packets successfully received and the data packets not successfully received by the terminal device, wherein the terminal device is switched from the first access network device to the second access network device.

[0050] In the seventh aspect, an access network device is provided, which may be a second access network device, a chip or module within the second access network device, or a chip or a system on chip, and the access network device includes: a transceiver unit for receiving a first data packet and first indication information from a core network device, wherein the first indication information is used to indicate the order of the first data packet in at least one data packet; a processing unit for determining a second sequence number of a first protocol layer of the first data packet based on the first indication information; and the transceiver unit for sending the first data packet to a first terminal device.

[0051] In combination with the seventh aspect, in certain implementations of the seventh aspect, the first indication information includes at least one of the following information: a General Packet Radio Service Tunneling Protocol-User Plane GTP-U sequence number, a first service sequence number; the first service sequence number is set by the core network device or the data server, the first data packet is a data packet of the first service, and the at least one data packet is a data packet of the first service.

[0052] In combination with the seventh aspect, in certain implementations of the seventh aspect, the first protocol layer includes at least one of the following: a service data adaptation protocol SDAP layer, a packet data convergence protocol PDCP layer, and a radio link control layer protocol RLC layer.

[0053] In combination with the seventh aspect, in certain implementations of the seventh aspect, the processing unit is also used to: when any of the following situations occurs: when the first protocol entity is newly created, the first protocol entity is rebuilt, and the first protocol entity is restored, set the starting sequence number of the first protocol layer of the first data packet according to the first indication information.

[0054] In combination with the seventh aspect, in certain implementations of the seventh aspect, the transceiver unit is further used to: send second indication information to the terminal device, the second indication information being used to indicate the sequence number of the first data packet belonging to the first service sent by the first access network device to the terminal device after the first protocol entity is newly established or the first protocol entity is rebuilt or the first protocol entity is restored.

[0055] In combination with the seventh aspect, in certain implementations of the seventh aspect, the transceiver unit is further used to: receive a data packet sent by a first access network device, wherein a second terminal device in the first access network device is switched from the first access network device to the second access network device, the first terminal device and the second terminal device both perform the first service, and the data packet sent by the first access network device is a data packet of the first service; when the second sequence number of the first protocol layer of the data packet currently being sent to the first terminal device is equal to or greater than the first sequence number of the first protocol layer of the data packet sent by the first access network device, send a third indication information to the first access network device, and the third indication information is used to instruct the first access network device to stop forwarding the data packet to the second access network device.

[0056] In combination with the seventh aspect, in certain implementations of the seventh aspect, the transceiver unit is also used to: receive status report information of the data packet sent by the second terminal device, the status report information of the data packet is used to indicate the second access network device, the data packets successfully received and the data packets not successfully received by the terminal device; and send fourth indication information to the first access network device based on the status report information, the fourth indication information is used to indicate the sequence number of the first data packet forwarded by the first access network device to the second access network device.

[0057] In combination with the seventh aspect, in certain implementations of the seventh aspect, the transceiver unit is also used to: send a fifth indication message to the first access network device, the fifth indication message including a second sequence number N, and the second sequence number is used to indicate the sequence number of the first data packet belonging to the first service sent by the second access network device to the second terminal device after the switching of the second terminal device is completed.

[0058] In an eighth aspect, a core network device is provided, which may be a core network device, a chip or module within the core network device, or a chip or system on chip, and the core network device includes: a transceiver unit, used to receive a first data packet sent by a data server; the transceiver unit is used to send a second data packet and first indication information to a first access network device, the first indication information being used to indicate the order of the second data packet in at least one data packet sent by the core network device; the transceiver unit is used to send a third data packet and second indication information to a second access network device, the first indication information being used to indicate the order of the third data packet in at least one data packet sent by the core network device, and the data of the second data packet and the data of the third data packet are the same as the data of the first data packet.

[0059] In combination with the eighth aspect, in certain implementations of the eighth aspect, the first indication information includes at least one of the following information: a General Packet Radio Service Tunneling Protocol-User Plane GTP-U sequence number, a first service sequence number; the first service sequence number is set by the core network device or the data server, the first data packet is a data packet of the first service, and the at least one data packet is a data packet of the first service.

[0060] In the ninth aspect, a communication device is provided, comprising a processor, the processor being connected to a memory, the memory being used to store a computer program, the processor being used to execute the computer program stored in the memory, so that the device executes the method in the above-mentioned first aspect or any possible implementation of the first aspect, or the method in the second aspect or any possible implementation of the second aspect, or the method in the third aspect or any possible implementation of the third aspect, or the method in the fourth aspect or any possible implementation of the fourth aspect.

[0061] In the tenth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed, the method in the first aspect or any possible implementation of the first aspect, or the method in the second aspect or any possible implementation of the second aspect, or the method in the third aspect or any possible implementation of the third aspect, or the method in the fourth aspect or any possible implementation of the fourth aspect is implemented.

[0062] In the eleventh aspect, a chip is provided, characterized in that it includes a processor and an interface; the processor is used to read instructions to execute the method in the above-mentioned first aspect or any possible implementation of the first aspect, or the method in the second aspect or any possible implementation of the second aspect, or the method in the third aspect or any possible implementation of the third aspect, or the method in the fourth aspect or any possible implementation of the fourth aspect.

[0063] Optionally, the chip may further include a memory, in which instructions are stored, and the processor is used to execute the instructions stored in the memory or instructions derived from other sources.

[0064] In the twelfth aspect, a communication system is provided, which includes a device having functions for implementing the methods of the first aspect and various possible designs, a device having functions for implementing the methods of the second aspect and various possible designs, a device having functions for implementing the methods of the third aspect and various possible designs, and a device having functions for implementing the methods of the fourth aspect and various possible designs. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1It is a schematic diagram of an application scenario of an embodiment of the present application.

[0066] Figure 2 It is a schematic flow chart of a communication method in an embodiment of the present application.

[0067] Figure 3 It is a schematic flow chart of a method for switching a terminal device across access network devices in the prior art.

[0068] Figure 4 It is a schematic diagram of an application scenario of the multicast service of an embodiment of the present application.

[0069] Figure 5 It is a schematic flow chart of a communication method in an embodiment of the present application.

[0070] Figure 6 It is a schematic flow chart of data forwarding of a communication method according to an embodiment of the present application.

[0071] Figure 7 It is a schematic flow chart of a communication method in an embodiment of the present application.

[0072] Figure 8 It is a schematic block diagram of a communication device according to an embodiment of the present application.

[0073] Fig. 9 A schematic diagram of the structure of a terminal device provided for this application.

[0074] Fig.10 A schematic diagram of the structure of an access network device provided for this application. DETAILED DESCRIPTION

[0075] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0076] In order to better understand the present application, the terms that may appear in the embodiments of the present application are first explained.

[0077] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: global system for mobile communications (GSM) system, code division multiple access (CDMA) system, wideband code division multiple access (WCDMA) system, general packet radio service (GPRS), long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), universal mobile telecommunication system (UMTS), worldwide interoperability for microwave access (WiMAX) communication system, fifth generation (5G) system or new radio (NR), in addition, it can also be applicable to the use of subsequent evolution systems, such as sixth generation 6G communication system, or even more advanced seventh generation 7G communication system.

[0078] The terminal device in the embodiments of the present application may also be referred to as: user equipment (UE), mobile station (MS), mobile terminal (MT), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication equipment, user agent or user device, etc.

[0079] The terminal device can be a wireless terminal or a wired terminal. The wireless terminal can be a device that provides voice and / or other business data connectivity to the user, a handheld device with wireless connection function, or other processing equipment connected to a wireless modem. The wireless terminal can communicate with one or more core networks via the Radio Access Network (RAN). The wireless terminal can be a mobile terminal, such as a mobile phone (or "cellular" phone) and a computer with a mobile terminal, for example, a portable, pocket-sized, handheld, computer-built-in or vehicle-mounted mobile device, which exchanges language and / or data with the wireless access network. For example, Personal Communication Service (PCS) phones, cordless phones, Session Initiation Protocol (SIP) phones, Wireless Local Loop (WLL) stations, Personal Digital Assistants (PDA) and other devices.A wireless terminal may also be referred to as a system, a subscriber unit, a subscriber station, a mobile station, a mobile station, a remote station, a remote terminal, an access terminal, a user terminal, a user agent, a user device or user equipment, a mobile internet device (MID), a wearable device, a virtual reality (VR) device, an augmented reality (AR) device, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in remote medical surgery, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, a vehicle-mounted device, a wearable device, a terminal device in a 5G network, or a public land mobile communication network (publicland mobile communication network) to be evolved in the future. The embodiments of the present application do not limit this.

[0080] As an example and not a limitation, in the embodiments of the present application, wearable devices may also be referred to as wearable smart devices, which are a general term for wearable devices that are intelligently designed and developed by applying wearable technology to daily wear, such as glasses, gloves, watches, clothing, and shoes. A wearable device is a portable device that is worn directly on the body or integrated into the user's clothes or accessories. Wearable devices are not only hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include full-featured, large-sized, and independent of smartphones to achieve complete or partial functions, such as smart watches or smart glasses, as well as devices that only focus on a certain type of application function and need to be used in conjunction with other devices such as smartphones, such as various types of smart bracelets and smart jewelry for vital sign monitoring.

[0081] In addition, in the embodiments of the present application, the terminal device may also be a terminal device in an Internet of Things (IoT) system. IoT is an important part of the future development of information technology. Its main technical feature is to connect objects to the network through communication technology, thereby realizing an intelligent network that interconnects people and machines and things.

[0082] The various terminal devices introduced above, if located on a vehicle (eg, placed in or installed in a vehicle), can be considered as vehicle-mounted terminal devices, which are also called on-board units (OBU).

[0083] In the embodiment of the present application, the terminal device may also include a relay. Alternatively, it can be understood that anything that can communicate data with the base station can be regarded as a terminal device.

[0084] The access network device in the embodiment of the present application may be a device for communicating with a terminal device, may be a base station, or an access point, or a network device, or may refer to a device in an access network that communicates with a wireless terminal through one or more sectors on an air interface. The network device may be used to convert received air frames to and from IP packets, and serve as a router between the wireless terminal and the rest of the access network, wherein the rest of the access network may include an Internet Protocol (IP) network. The network device may also coordinate the attribute management of the air interface. For example, the access network device can be a base station (Base Transceiver Station, BTS) in Global System of Mobile communication (GSM) or Code Division Multiple Access (CDMA), or a base station (NodeB, NB) in Wideband Code Division Multiple Access (WCDMA), or an evolved base station (evolved NodeB, eNB or eNodeB) in an LTE system, or a wireless controller in a cloud radio access network (CRAN) scenario, or the access device can be a relay station, an access point, a vehicle-mounted device, a wearable device, and an access device in a 5G network or a network device in a future evolved PLMN network, etc. It can be an access point (AP) in a WLAN, or it can be a gNB in ​​a new wireless system (new radio, NR) system. The embodiments of the present application are not limited. It should be noted that for the 5G system, under one base station, there may be one or more transmission reception points (Transmission Reception Point, TRP), and all TRPs belong to the same cell, wherein each TRP and terminal can use the measurement reporting method described in the embodiment of the present application. In another scenario, the network device can also be divided into a control unit (Control Unit, CU) and a data unit (Data Unit, DU). Under one CU, there may be multiple DUs, wherein each DU and terminal can use the measurement reporting method described in the embodiment of the present application. The difference between the CU-DU separation scenario and the multi-TRP scenario is that the TRP is just a radio frequency unit or an antenna device, and the protocol stack function can be implemented in the DU, for example, the physical layer function can be implemented in the DU.

[0085] In addition, in the embodiment of the present application, the access network device is a device in the access network (radio access network, RAN), or in other words, a RAN node that connects the terminal device to the wireless network. For example, as an example but not a limitation, the access network device can be listed as: gNB, transmission reception point (TRP), evolved Node B (eNB), radio network controller (RNC), Node B (NB), base station controller (BSC), base transceiver station (BTS), home base station (e.g., home evolved NodeB, or home Node B, HNB), base band unit (BBU), or wireless fidelity (Wifi) access point (AP), etc.

[0086] The access network device provides services for the cell, and the terminal device communicates with the access network device through the transmission resources used by the cell (for example, frequency domain resources, or spectrum resources). The cell may be a cell corresponding to the access network device (for example, a base station). The cell may belong to a macro base station or a base station corresponding to a small cell. The small cells here may include: metro cells, micro cells, pico cells, femto cells, etc. These small cells have the characteristics of small coverage and low transmission power, and are suitable for providing high-speed data transmission services.

[0087] Unicast: Point-to-point communication technology, that is, single-point communication between network devices and terminal devices. Network devices can send data to each terminal device separately. Unicast can also be called unicast transmission mode or unicast transmission technology.

[0088] Sending by unicast transmission means that: when a sending device sends a transport block (TB) corresponding to a protocol data unit (PDU), a cell network temporary identifier (C-RNTI) is used to scramble the PDU, or the downlink control information (DCI) corresponding to the PDU is scrambled, and a receiving device receives the same PDU according to the C-RNTI; or transmitting the PDU by unicast may mean that the PDU is transmitted in a wireless bearer established for unicast transmission or in a channel specially designed for unicast.

[0089] Receiving in unicast transmission mode means that when sending in unicast mode, the receiving device receives the PDU according to the C-RNTI; or the receiving device receives through a wireless bearer established for unicast transmission or receives on a channel used for unicast transmission.

[0090] Multicast: Point-to-multipoint communication technology, also known as multicast transmission mode or multicast transmission technology, used to serve multimedia broadcast and multicast services. Multicast can also be called groupcast, and in some broad scenarios it can also be called a broadcast technology, but there are differences between multicast and traditional broadcast technology. When using the multicast transmission mode, for the same data, multiple terminal devices simultaneously receive it during the transmission process of a network device (such as a base station). Currently, multicast transmission technologies are mainly divided into two types: multimedia broadcast multicast service single frequency network (MBSFN) and single cell point to multipoint (SC-PTM). In addition, other multicast transmission technologies are also being discussed, and the present invention does not limit them.

[0091] Transmitting by multicast transmission means that: when the transmitting device sends the transport block (TB) corresponding to the protocol data unit (PDU), the group radio network temporary identifier (G-RNTI) is used to scramble the PDU, or the downlink control information (DCI) corresponding to the PDU is scrambled, and one or more receiving devices receive the same PDU according to the same G-RNTI. Alternatively, transmitting the PDU by multicast may refer to notifying multiple receiving devices of the location of the same PDU in a semi-static manner, and multiple receiving devices may receive the PDU at the same time. Alternatively, transmitting the PDU by multicast may refer to transmitting the PDU in a radio bearer established for multicast transmission or in a channel specially designed for multicast.

[0092] Receiving through multicast transmission means that when the other side sends in multicast mode, one of the multiple receiving devices receives the PDU according to the G-RNTI; or one of the multiple receiving devices receives the PDU through a wireless bearer established for multicast transmission or on a channel used for multicast transmission.

[0093] Broadcast: Point-to-multipoint communication technology. Unlike multicast, the technology involved in broadcast is that the sending device sends the TB corresponding to the PDU on the broadcast channel, and all receiving devices can receive the PDU on the broadcast channel. Unlike multicast technology, in the traditional broadcast transmission, the broadcast channel does not use the above-mentioned G-RNTI scrambling method.

[0094] Handover (HO): Switching an ongoing call from one radio channel to another to ensure uninterrupted communication. In a wireless communication system, each cell covers a limited area. Therefore, when a terminal device moves from the current serving cell to an adjacent cell, in order to ensure service continuity, the network side needs to switch the service to the adjacent cell so as not to interrupt the communication process. Handover refers to the process of switching the link that carries communication data from one cell (or base station) to another cell (or base station) to ensure uninterrupted communication during the communication process.

[0095] Protocol Stack: Network devices and terminal devices have a certain protocol layer structure for mutual communication. For example, the control plane protocol layer structure may include a radio resource control (RRC) layer, a packet data convergence layer protocol (PDCP) layer, a radio link control (RLC) layer, a media access control (MAC) layer, and a physical layer. The user plane protocol layer structure may include a PDCP layer, an RLC layer, a MAC layer, and a physical layer. Among them, the physical layer is located at the lowest layer (layer one), the MAC layer, RLC, and PDCP belong to the second layer (layer two), and the RRC belongs to the third layer (layer three). In one implementation, a service data adaptation protocol (SDAP) layer may also be included above the PDCP layer. In addition, above the SDAP layer, there may be a transmission layer such as a transmission control protocol / Internet protocol (TCP / IP) layer and an application layer.

[0096] The functions of these protocol layers can be implemented by one node or multiple nodes; for example, in an evolutionary structure, the wireless access network equipment may include a centralized unit (CU) and a distributed unit (DU), and multiple DUs may be centrally controlled by one CU. The CU and DU may be divided according to the protocol layers of the wireless network, for example, the functions of the PDCP layer and above protocol layers are set in the CU, and the functions of the protocol layers below the PDCP, the RLC layer and the MAC layer, etc. are set in the DU, etc.

[0097] It should be understood that this division of the protocol layer is only an example, and it can also be divided in other protocol layers, such as dividing in the RLC layer, setting the functions of the RLC layer and the protocol layers above the RLC layer in the CU, and the functions of the protocol layers below the RLC layer in the DU; or dividing in a certain protocol layer, for example, setting some functions of the RLC layer and the functions of the protocol layers above the RLC layer in the CU, and setting the remaining functions of the RLC layer and the functions of the protocol layers below the RLC layer in the DU. In addition, it can also be divided in other ways, such as dividing by latency, setting the functions whose processing time needs to meet the latency requirements in the DU, and the functions that do not need to meet the latency requirements in the CU.

[0098] Radio Bearer: Generally, it can be understood as the transmission path or treatment that a data packet or signaling passes through when it is transmitted on the air interface. Radio bearers include data radio bearers and signaling radio bearers. Radio bearers are established and configured through the RRC signaling of network equipment. The configuration of the radio bearer includes the configuration of each protocol layer. The entities of each protocol layer of the network equipment and the terminal equipment send, receive or process data packets or signaling in the radio bearer according to the configuration. Technically, a radio bearer can be understood as a transmission channel. Whether on the terminal device side or on the network device side, each radio bearer includes a PDCP entity and at least one RLC entity to process data packets transmitted in the radio bearer. In addition to establishing radio bearers, network equipment can also add, modify or delete (release) radio bearers through RRC signaling.

[0099] Multimedia broadcast multicast service is a one-way multimedia service for point-to-multipoint transmission. For example, multimedia broadcast services are sent to users in a cell through a common channel on the air interface, or multicast services subscribed by users are sent to users in a cell in a multicast manner, thereby saving air interface resources.

[0100] An application scenario of an embodiment of the present application is introduced below. Figure 1 A schematic diagram of an application scenario 100 of an embodiment of the present application is shown. Figure 1 The system includes an access network device 110, a terminal device 120, a terminal device 130, a terminal device 140, a terminal device 150, a terminal device 160 and a terminal device 170. The access network device 110 works in an evolved UMTS terrestrial radio access (E-UTRA) system, or in an NR system, or in a next generation communication system or other communication systems, and the access network device 110 and the terminal devices 120 to 170 can communicate through a Uu interface. In the communication system, the terminal devices 120 to 170 can send uplink data to the access network device 110, and the access network device 110 can send downlink data to the terminal devices 120 to 170. In addition, the terminal devices 150 to 170 can also form a communication system. The access network device 110 can send downlink data to the terminal devices 120 to 150, wherein the access network device 110 sends the downlink data to the terminal devices 120 and 150 in a unicast manner, and the access network device 110 sends the downlink data to the terminal devices 130 and 140 in a multicast manner. The terminal device 150 can also send downlink data to the terminal devices 160 and 170.

[0101] Figure 1 The access network device in the embodiment is, for example, a base station. The access network device corresponds to different devices in different systems. For example, in a 4G system, it may correspond to an eNB, and in a 5G system, it may correspond to an access network device in 5G, such as a gNB. The technical solution provided in the embodiment of the present application may also be applied to future mobile communication systems, so Figure 1 The access network equipment in the present invention may also correspond to the access network equipment in the future mobile communication system. Figure 1 Taking the access network device as a base station as an example, the access network device can actually refer to the introduction in the previous article.

[0102] It should be understood that Figure 1 The communication system shown may also include more network nodes, such as other terminal devices or access network devices. Figure 1 The access network device or terminal device included in the communication system shown may be any of the above-mentioned various forms of access network devices or terminal devices. The embodiments of the present application are not shown one by one in the figures.

[0103] The technical solution in this application can also be used in other communication systems as long as the transmission direction needs to be indicated in the communication system. In addition, this application is not only applicable to the scenario of multiple UEs in one access network device (such as SC-PTM scenario), but also applicable to the scenario of multiple access network devices cooperating to communicate data with multiple UEs at the same time (such as MBSFN scenario), as well as the multicast broadcast scenario in 5G.

[0104] Combine the following Figure 2 A communication method provided by the present application is described in detail. Figure 2 is a schematic flow chart of a communication method 200 according to an embodiment of the present application. The method 200 can be applied in Figure 1 The scenario shown can of course also be applied to other communication scenarios, and the embodiments of the present application are not limited here.

[0105] It should also be understood that in the embodiments of the present application, the method is described by taking the terminal device, the access network device and the core network device as the execution subject of the execution method. As an example but not a limitation, the execution subject of the execution method may also be a chip, a chip system, or a processor applied to the terminal device, the access network device and the core network device.

[0106] like Figure 2 As shown, Figure 2 The method 200 shown in FIG. 2 may include S201 to S210. Figure 2 Each step in method 200 is described in detail.

[0107] S201, a data server sends at least one data packet of a first service to a core network device.

[0108] Optionally, when the data server sends at least one data packet of the first service to the core network device, the data server may carry progress indication information of the first service, where the progress indication information is used to indicate the position of the current data packet in at least one data packet of the first service, and the progress indication information of the first service may be the sequence number of the first service. The progress indication information may be carried in the data packet, such as in the packet header, or the indication information may be sent separately from the data packet.

[0109] Optionally, before S201, the data server receives a request message sent by the core network device, and the request message is used to request the data server to carry progress indication information of the first service when sending at least one data packet of the first service to the core network device. When the data server receives the request message sent by the core network device, and sends at least one data packet of the first service to the core network device, the data server may carry the progress indication information of the first service in each data packet.

[0110] Optionally, the first service may be an MBMS service.

[0111] S202: The core network device receives at least one data packet of the first service sent by the data server.

[0112] Specifically, when the core network device receives at least one data packet of the first service sent by the data server, it determines the access network device that needs to receive the first service, and sends the at least one data packet to different access network devices respectively.

[0113] S203, the core network device sends a first data packet and first indication information to the first access network device, where the first indication information is used to indicate the order of the first data packet in at least one data packet sent by the core network device.

[0114] It is worth noting that in this embodiment, S201 and S202 are only optional steps, and S203 is not limited to be dependent on S201 and S202. The data packets received by the specific core network device may be received from other places or generated by itself. Optionally, progress indication information may also be received from other places, and the order of each data packet is determined according to the progress indication information. In addition, it is not limited how the core network sends data packets to different access network devices.

[0115] S204, the core network device sends a second data packet and second indication information to the second access network device, where the first indication information is used to indicate the order of the second data packet in at least one data packet sent by the core network device. The data of the first data packet and the data of the second data packet may be the same or different, and there is no restriction on this. When the data in the data packet received by the first access network device is the same as the data in the data packet received by the second access network device, the first indication information is the same as the second indication information.

[0116] Exemplarily, the core network device sends five data packets with core network sequence numbers 1-5 to the first access network device, and sends five data packets with core network sequence numbers 5-9 to the second access network device. Then, the last data packet of the five data packets received by the first access network device has the same content and size as the first data packet of the five data packets received by the second access network device, and the indication information corresponding to these two data packets is the same.

[0117] Specifically, when the core network device sends at least one data packet of the first service to the access network device, in order to enable the access network device to understand the sending progress of the first service, the first indication information can be carried, and the first indication information can be implemented by setting a core network sequence number for the data packet. When the core network device sends data packets received from a data server to different access network devices, for the same data packet (carrying the same content or load), it carries the same core network sequence number, that is, the same first indication information, and the first indication information is used to identify the position of the data packet in at least one data packet sent.

[0118] Optionally, the first indication information includes at least one of the following information: a General Packet Radio Service Tunneling Protocol-User Plane Sequence Number (GPRS Tunneling Protocol-U Sequence Number, GTP-U), a first service sequence number; wherein, the first service sequence number is set by the core network device or the data server, the first data packet is a data packet of the first service, and the at least one data packet is a data packet of the first service.

[0119] The following is a brief description of the first service sequence number using the GTP-U sequence number as an example. Currently, when the core network device and the access network device are transmitting data, the core network device establishes different PDU sessions or GTP tunnels with different access network devices to operate independently. Therefore, even if the core network device receives the same data packet from the data server, when sending it to different access network devices, different GTP-U SN numbers may be set. In the present application, for the same data packet received by the core network device from the data server or generated by the core network device itself, when sending it to different access network devices, the core network device sets the same GTP-U SN number. One possible implementation method is that each data packet sets the GTP-U SN number according to the indication information of the data server. In this way, since the GTP-U SN number is associated with the data packet content, different access network devices can judge the transmission progress of the service according to the GTP-U SN number.

[0120] Optionally, when the data server sends at least one data packet of the first service to the core network device, if the data server carries the first service sequence number corresponding to at least one data packet, the core network device may send a first indication message to the access network device according to the first service sequence number, and the first indication message may be the first service sequence number carried by the at least one data packet. When the data server sends at least one data packet of the first service to the core network device, if the data server does not carry the first service sequence number, the core network device resets the first service sequence number of the at least one data packet according to the order in which the at least one data packet is received. For example, when the core network device receives data packet 1, data packet 2, and data packet 3 from the data server, the first service sequence number 1 may be set for data packet 1, the first service sequence number 2 may be set for data packet 2, and the first service sequence number 3 may be set for data packet 3.

[0121] S205, the first access network device receives the first data packet and the first indication information from the core network device.

[0122] It is worth noting that in this embodiment, S205 is not limited to the specific implementation method of the previous steps, and it is only necessary to receive the first data packet and the first indication information from the core network device.

[0123] S206: The first access network device determines a first sequence number of a first protocol layer of the first data packet according to the first indication information.

[0124] The optional first protocol layer includes at least one of the following protocol layers: a service data adaptation protocol SDAP layer, a packet data convergence protocol PDCP layer and a radio link control layer protocol RLC layer.

[0125] It should be understood that the first protocol layer may be a high-level protocol layer on the wireless access network side, and the first protocol layer may also be referred to as a layer 2 protocol layer, and SDAP, PDCP, RLC, and MAC all belong to layer 2 protocols. In addition, new protocol layers may be introduced in subsequent technologies for new functions, so this embodiment does not limit the first protocol layer to an existing protocol layer, and may also be a newly defined protocol layer.

[0126] Specifically, after receiving the first data packet, the first access network device determines the first serial number of the first protocol layer of the first data packet according to the first indication information. The first serial number of the first protocol layer is used by the first protocol layer to process the first data packet, such as sorting, duplicate detection, etc.

[0127] Optionally, when the first access network device establishes a first protocol layer entity for multicast transmission, or when the first protocol layer entity that has been established for multicast transmission undergoes a re-establishment process or a first protocol layer entity data recovery process, the first protocol layer entity of the first access network device determines the starting sequence number of the first data packet according to the first indication information. Taking the PDCP entity as an example, after the PDCP entity for multicast transmission is reestablished, the first indication information of the first data packet received by the access network device, for example, when the first indication information is the core network sequence number, the core network sequence number corresponding to the first data packet is 5, then the access network device also sets the PDCP sequence number of the first data packet to 5, instead of starting from 0 as in the prior art. Even if the first protocol layer entity is reestablished or recovered, it can be ensured that the information corresponding to the data packet is the current actual service progress information.

[0128] S207, the second access network device receives the second data packet and the first indication information from the core network device.

[0129] S208: The second access network device determines a second sequence number of the first protocol layer of the second data packet according to the first indication information.

[0130] In step S206 and step S208, after receiving the data packet and the core network sequence number sent by the core network device, the first access network device and the second access network device need to determine the sequence number of the received data packet. Figure 6A brief description is given for this. A first access network device receives a first data packet whose core network sequence number GTP-U SN is 8, and the first access network device determines that the PDCP SN of the first data packet is 8 according to the GTP-U SN of the first data packet; a second access network device receives a data packet whose core network sequence number GTP-U SN is 11, and the second access network device determines that the PDCP SN of the second data packet is 11 according to the GTP-U SN of the second data packet. PDCP is an example of the first protocol layer.

[0131] It should be understood that the second access network device may also be the first access network device. The description of the second access network device can refer to the above description of the first access network device, which will not be repeated here.

[0132] It should also be understood that the core network device sends the same first service to the first access network device and the second access network device, and carries the same first indication information for the data packets with the same content, so that the first access network device and the second access network device can determine the same first protocol layer sequence number for the data packets with the same content according to the same first indication information, that is, the first protocol layer sequence numbers determined by different access network devices for the data packets with the same data are the same. Therefore, in the process of the terminal device switching from the first access network device to the second access network device, the second access network device can obtain the first service progress of the first access network device according to the SN state forwarding and data forwarding steps in the existing switching process, without introducing additional progress interaction information between the two access network devices.

[0133] This embodiment involves multiple sequence numbers, wherein each protocol layer of a data server, a core network device, an access network device, and a terminal device may set a sequence number belonging to each protocol layer. For example, the core network sequence number is a sequence number set by the core network device for a data packet, and the PDCP sequence number is a sequence number set by the PDCP layer of an access network device or a terminal device for a data packet. Different sequence numbers are located in different packets of the same data packet, have different functions, and are only visible to the corresponding devices or protocol layers. In addition, "sequence number" is a general term for all sequence numbers, and is not limited to a specific type of sequence number. It is necessary to determine the specific type of sequence number based on the scenario. For example, the sequence number of the PDCP layer is the PDCP sequence number.

[0134] Another point worth noting is that when a data packet is sent from a core network device to an access network device and then to a terminal device, it will be processed by many different protocol layers (such as adding a packet header). These processes are for transmission needs. After processing, the size or form of the data packet may change, but as long as the content of the data packet payload does not change, it can be called the same data packet, such as the first data packet.

[0135] S209: The first access network device sends the first data packet to the first terminal device.

[0136] Optionally, the first access network device may send second indication information to the first terminal device, where the second indication information is used to indicate the sequence number of the first data packet of the first service sent by the first access network device to the first terminal device after the first protocol entity of the first terminal device is newly established or the first protocol entity is rebuilt or data is recovered.

[0137] As a possible implementation, before the first terminal device starts to receive the first service, the first protocol entity first obtains configuration information for receiving the first protocol entity from the first access network device when it is newly established. The first access network device carries second indication information in the configuration information, which is used to indicate the sequence number (e.g., PDCP SN) of the first data packet of the first service sent by the first access network device. In this way, the terminal device can know the sequence number of the first data packet that should be received. If the sequence number of the first received data packet is greater than the sequence number indicated by the indication information, it means that a data packet has been lost. The terminal device can determine the lost data packet and request the access network device to retransmit the lost data packet.

[0138] In addition, when the first protocol entity used by the terminal device to transmit the first service undergoes a reconstruction process or the first protocol entity undergoes a data recovery process, the access network device also needs to send the second indication information to the first terminal device, which is used to indicate the sequence number (for example, PDCP SN) of the first data packet of the first service sent by the first access network device, thereby preventing the loss of data packets due to inconsistent understanding of the first data packet by the first terminal device and the first access network device.

[0139] S210, the second access network device sends the second data packet to the second terminal device.

[0140] Optionally, the second access network device may send the second indication information to the second terminal device. For a specific description, please refer to the relevant description in S209 and will not be repeated here.

[0141] A communication method 200 provided in the present application can realize that during the process of a terminal device switching from the first access network device to the second access network device, the second access network device can obtain the first service progress of the first access network device based on the SN state forwarding and data forwarding steps in the existing switching process, without introducing additional progress interaction information between the two access network devices, thereby avoiding the situation where the terminal device redundantly receives data packets or service data interruption caused by inconsistent multicast service progress of different access network devices.

[0142] In order to better understand the beneficial effects of the method provided by the present application, the following briefly introduces the switching process of terminal equipment across access network equipment (taking base stations as an example) in the prior art. Figure 3 As shown, Figure 3 It is a schematic flow chart of a method 300 for switching a terminal device across access network devices in the prior art. The switching is a switching process initiated by the source gNB. The source base station (Source gNB, SgNB) decides to switch the UE based on the measurement report reported by the UE, and initiates a switching request to the target base station (Target gNB, TgNB). After the SgNB obtains the positive switching response from the TgNB, the SgNB sends a switching command to the UE. When the UE receives the switching command, the UE stops sending uplink or downlink data with the SgNB, and the UE starts to synchronize with the TgNB and initiates a random access process. When the SgNB sends a switching command to the UE, it stops uplink or downlink data transmission with the UE, and sends the data stored in the SgNB to the TgNB. After successfully accessing the TgNB, the UE starts to transmit uplink or downlink data with the TgNB. Figure 3 The method 300 shown in FIG. 3 may include S301 to S308. Figure 3 Each step in method 300 is briefly described.

[0143] S301, in the handover preparation phase, the UE in the RRC connected state sends a "Measurement Report" according to the measurement report triggering criteria configured by the base station.

[0144] S302: The source gNB determines the target gNB for the UE based on the UE's measurement report and the radio resource management algorithm RRM algorithm when the UE meets the switching conditions, and sends the UE context information to the target gNB along with the switching request.

[0145] S303, the target gNB prepares for the UE to be handed over, and allocates the cell identification parameter C-RNTI and other parameters to the UE, and returns them to the source gNB in ​​the handover request confirmation message. After receiving the handover request confirmation message, the source gNB prepares to forward the packet data to the target gNB.

[0146] S304, SgNB sends a "Handover Command" to the UE (the handover command includes the following information: new C-RNTI, SIB of the target gNB, UE configuration information, such as MAC, RLC, PDCP layer configuration, etc.). After receiving the handover command, the UE stops uplink or downlink data transmission with the source gNB and synchronizes with the target gNB.

[0147] At this time, the source gNB forwards the cached uplink data sent by the UE and the downlink data sent by the UPF to the target gNB.

[0148] S305, the source station sends SN status information and data forwarding to the target station (dashed line step).

[0149] S306, after the UE disconnects the data transmission with the source gNB, it starts the downlink synchronization process with the target gNB, and then initiates the random access process to obtain the uplink timing and uplink resource allocation. The target gNB sends the tracking area TA to the UE and indicates the resources allocated to it to the UE. This information will be used by the UE to send an RRC connection reconfiguration complete message to the target gNB to indicate that the handover is complete.

[0150] S307: The UE sends a "handover confirmation" message to the target gNB, indicating that the handover is complete.

[0151] S308: The target gNB indicates to the source gNB that the handover is complete so that the source gNB can release the context information of the UE.

[0152] At the same time, the target gNB notifies the core network node to update the data forwarding destination gNB information so that the core network can send the UE's data to the target gNB.

[0153] In the prior art, in some multicast application scenarios, a UE receives a multicast (groupcast) service at one base station, and moves at a certain moment, and needs to execute a switching process to switch to another base station to receive the multicast service. When the progress of the multicast services of the two base stations is inconsistent, the existing switching process may cause the UE to receive redundant data packets or cause the UE to experience data interruption. Figure 4 As shown, Figure 4 FIG. 4 is a schematic diagram showing a multicast service switching scenario 400. Figure 4 The core network device 410, access network device 420, access network device 430, terminal device 440 and terminal device 450 are included. Access network device 420 and access network device 430 receive multicast service data sent by core network device 410 and send them to terminal devices within their coverage. Terminal device 450 is switched from access network device 420 to access network device 430. The progress of multicast services of access network device 420 and access network device 430 is inconsistent. The existing switching process may cause terminal device 450 to receive redundant data packets or cause data interruption in terminal device 450.

[0154] In order to solve this problem, the present application provides a communication method 500. Figure 5 A communication method provided by the present application is described in detail. Figure 5 is a schematic flow chart of a communication method 500 according to an embodiment of the present application. The method 500 can be applied in Figure 1 The scenario shown can of course also be applied to other communication scenarios, and the embodiments of the present application are not limited here. In the method 500, the first terminal device in the first access network device is switched from the first access network device to the second access network device, and the first access network device and the second access network device both perform the first service.

[0155] It should be understood that before and after the first terminal device switches, the first terminal device uses the same protocol entity to process the data packets received from the first access network device and the second access network device before and after the switching, such as sorting and duplication detection.

[0156] It should also be understood that in the embodiments of the present application, the method is described by taking the terminal device and the access network device as the execution subject of the execution method. As an example but not a limitation, the execution subject of the execution method may also be a chip, a chip system, or a processor applied to the terminal device and the access network device.

[0157] like Figure 5 As shown, Figure 5 The method 500 shown in FIG. 5 may include S501 to S505. Figure 5 Each step in method 500 is described in detail.

[0158] S501, the first access network device forwards a data packet to the second access network device, where the data packet sent by the first access network device is a data packet of the first service.

[0159] S502: The second access network device receives a data packet sent by the first access network device.

[0160] Specifically, during the switching process, the first access network device needs to forward the data sent from the core network device and not successfully sent to the first terminal device to the second access network device, which is the data forwarding process. Since the serial numbers of the first protocol layers of the two access network devices are determined based on the first indication information sent by the core network device, for data packets with the same content, the serial numbers of the first protocol layers determined by the two access network devices are the same. Therefore, after the second access network device receives the data packet forwarded by the first access network device, it can know the sending progress of the first service in the first access network device based on the serial number of the first protocol layer of the data packet, and can adopt a corresponding sending strategy to ensure the service continuity of the first terminal device.

[0161] S503, the second access network device determines whether to send third indication information to the first access network device based on the second sequence number of the first protocol layer of the data packet currently being sent to the first terminal device and the first sequence number of the first protocol layer of the data packet received from the first access network device, the third indication information being used to instruct the first access network device to stop forwarding the data packet to the second access network device.

[0162] Optionally, when the second sequence number of the first protocol layer of the data packet currently being sent by the second access network device to the first terminal device is equal to or greater than the first sequence number of the first protocol layer of the data packet sent by the first access network device, the second access network device sends third indication information to the first access network device.

[0163] Optionally, when the second sequence number of the first protocol layer of the data packet currently being sent by the second access network device to the first terminal device is N, and the first sequence number of the first protocol layer of the data packet sent by the first access network device is N-1, the second access network device sends third indication information to the first access network device.

[0164] Specifically, after the terminal device is successfully switched, the second access network device starts to send data packets of the first service to the terminal device, and at the same time, the first access network device forwards data packets of the first service that the terminal has not successfully received from the first access network device to the second access network device. When the sequence number of the data packet received by the second access network device from the first access network device is greater than or equal to the sequence number of the data packet sent to the terminal device, the data forwarding is instructed to stop. For the first service, if the sending progress of the second access network device is fast, such as Figure 6 As shown, Figure 6It is a schematic flow chart of data forwarding of a communication method of an embodiment of the present application, in which a user plane function receives a data packet of a first service sent by a data server, and the data server carries indication information such as a service sequence number when sending the data packet of the first service, and the user plane function sends the received data packet of the first service to the first access network device and the second access network device respectively, but the progress of the user plane function sending data packets to the first access network device and the second access network device is inconsistent. The largest sequence number among the data packets of the first service sent by the first access network device is SN=8, and the largest sequence number among the data packets of the first service sent by the second access network device is SN=11. At this time, after the first terminal device switches to the second access network device, if the first service is received according to the sending progress of the second access network device, the data packets with SNs of 9 and 10 will be lost, so the first access network device forwards the data packets with SNs of 9 and 10 to the second access network device. When the progress of the data packets forwarded from the first access network device catches up with the sending progress of the second access network device, that is, when the sequence number of the data packet received by the second access network device from the first access network device is greater than or equal to the SN of the first data packet of the first service sent by the second access network device after the terminal device successfully switches to the second access network device, the second access network device sends a stop indication message to the first access network device, indicating the end of data forwarding.

[0165] As an optional implementation manner, the third indication information may include identification information of the first service.

[0166] S504: The first access network device receives the third indication information from the second access network device.

[0167] S505: The first access network device stops forwarding data packets to the second access network device according to the third indication information.

[0168] Specifically, the first access network device stops forwarding data after receiving the indication information, and continues to forward data before receiving the stop indication information from the target station.

[0169] Therefore, during the switching process of the first terminal device, the second access network device determines whether the data forwarding of the first access network device can be stopped, and sends data forwarding stop indication information to the first access network device, thereby ensuring the continuity of the terminal device receiving multicast services during the switching process and avoiding packet loss or redundant transmission.

[0170] Optionally, before step S501, the method 500 may further include:

[0171] The second access network device receives status report information of the data packet sent by the first terminal device, where the status report information of the data packet is used to indicate to the second access network device the data packets of the first service that have been successfully received and the data packets that have not been successfully received by the first terminal device;

[0172] The second access network device sends fourth indication information to the first access network device according to the status report information, where the fourth indication information is used to indicate the sequence number of the first data packet forwarded by the first access network device to the second access network device, where the first data packet refers to the data packet that the first access network device starts to forward to the second access network device during the data forwarding process or the data packet with the smallest sequence number among all forwarded data packets;

[0173] The first access network device receives fourth indication information sent by the second access network device;

[0174] The first access network device forwards the data packet to the second access network device according to the fourth indication information.

[0175] Specifically, after switching, the first terminal device sends status report information of the data packet to the second access network device, indicating the second access network device which data packets the first terminal device has successfully received and which data packets have not been successfully received. After receiving the status report information, the second access network device sends the fourth indication information to the first access network device. The fourth indication information indicates the first protocol layer sequence number of the first data packet that the first terminal device has not received, that is, the starting data packet for data forwarding by the first access network device. This can avoid the first terminal device from receiving redundant data packets, that is, although the data packet sent by the first access network device is successfully received by the first terminal device, it is still forwarded by the first access network device to the second access network device, and then sent to the first terminal device by the second access network device.

[0176] The present application provides a communication method 600, which is combined with Figure 7 A communication method provided by the present application is described in detail. Figure 7 is a schematic flow chart of a communication method 600 of an embodiment of the present application. The method 600 can be applied in Figure 1The scenario shown can of course also be applied to other communication scenarios, and the embodiments of the present application are not limited here. In the method 600, during the process of the first terminal device in the first access network device switching from the first access network device to the second access network device, the terminal device simultaneously maintains connection with the first access network device and the second access network device, so that the first access network device and the second access network device can simultaneously send the first service to the terminal device. On the one hand, the first access network device can continue to send data packets that were not successfully received before the terminal device switched, and on the other hand, the terminal device can also receive data packets of the first service from the second access network device. When the sequence number of the data packet received from the first access network device can be continuous with the sequence number of the data packet received from the second access network device (for example, a data packet with a maximum SN of 9 is received from the first access network device, and a data packet with a minimum SN of 10 is received from the second access network device), the first access network device can stop sending data packets to the terminal device and can disconnect the connection with the terminal device.

[0177] It should also be understood that in the embodiments of the present application, the method is described by taking the terminal device and the access network device as the execution subject of the execution method. As an example but not a limitation, the execution subject of the execution method may also be a chip, a chip system, or a processor applied to the terminal device and the access network device.

[0178] like Figure 7 As shown, Figure 7 The method 600 shown in FIG. 6 may include S601 to S603. Figure 7 Each step in method 600 is described in detail.

[0179] S601, the second access network device sends a fifth indication message to the first access network device, and the fifth indication message includes a first sequence number N, and the first sequence number is used to indicate the sequence number of the first data packet of the first service sent by the second access network device to the first terminal device after the first terminal device successfully switches from the first access network device to the second access network device.

[0180] S602: The first access network device receives fifth indication information sent by the second access network device.

[0181] S603: When the sequence number of the data packet successfully sent by the first access network device to the terminal device is N-1, the first access network device stops sending data packets to the terminal device.

[0182] Therefore, during the switching process, the first access network device decides when to stop the connection of the terminal device based on the SN indicated by the second access network device, thereby ensuring the continuity of the terminal device receiving multicast services during the switching process and avoiding packet loss or redundant transmission.

[0183] Specifically, during the switching process, the first terminal device receives the data packet of the first service from the first access network device and the second access network device at the same time, and the first access network device does not need to forward the data packet of the first service to the second access network device, that is, no data forwarding process is required, for example, Figure 5 In the example, the data packets with SNs of 9 and 10 are not forwarded but are directly sent to the first terminal device through the first access network device. After the first terminal device successfully switches to the second access network device, the second access network device can send the SN (for example, 11) of the first data packet of the first service sent to the terminal device to the first access network device. The first access network device decides when to stop sending data to the first terminal device based on the SN of the first data packet. When the first protocol layer sequence number of the data packet successfully sent by the first access network device to the terminal device is N-1, the first access network device stops sending data packets to the first terminal device, such as in Figure 5 In the embodiment, after the first access network device sends data packet No. 11-1=10, it disconnects from the first terminal device.

[0184] Optionally, the first access network device sends a stop indication message to the second access network device, instructing the first access network device to disconnect from the first terminal device.

[0185] Optionally, when the terminal device successfully switches to the second access network device, the second access network device may send information about the successful switching of the first terminal device to the first access network device. After the first access network device receives the information about the successful switching of the first terminal device, the first access network device sends the first sequence number of the first protocol layer that was most recently sent to the first terminal device to the second access network device. The second access network device determines whether the first access network device stops sending data packets of the first service to the first terminal device based on the first sequence number of the first protocol layer and the second sequence number of the first protocol layer. The second sequence number of the first protocol layer is the first protocol layer sequence number of the first data packet received from the second access network device after the first terminal device switches from the first access network device to the second access network device. When the first sequence number of the first protocol layer is greater than the second sequence number of the first protocol layer, the second access network device sends indication information to the first access network device to instruct the first access network device to disconnect from the first terminal device.

[0186] Optionally, the second access network device sends fifth indication information to the first access network device, and the fifth indication information includes a first sequence number N-1, and the first sequence number is used to indicate that when the first protocol layer sequence number of the data packet successfully sent by the first access network device to the terminal device is N-1, the first access network device stops sending data packets to the terminal device.

[0187] Therefore, the first access network device does not need to perform calculations again, and can stop sending the data packet directly when the first sequence number is N-1.

[0188] Combination of the above Figures 1 to 7 The communication parameter measurement method of the multi-card terminal device in the embodiment of the present application is described in detail. Figures 8 to 10 The communication device according to the embodiment of the present application is described in detail.

[0189] Figure 8 A schematic block diagram of a communication device 700 according to an embodiment of the present application is shown.

[0190] In some embodiments, the apparatus 700 may be a terminal device, or may be a chip or a circuit, such as a chip or a circuit that may be disposed in a terminal device.

[0191] In some embodiments, the apparatus 700 may be an access network device, or may be a chip or a circuit, such as a chip or a circuit that may be disposed in an access network device.

[0192] In some embodiments, the apparatus 700 may be a core network device, or may be a chip or a circuit, such as a chip or a circuit that may be disposed in a core network device.

[0193] In one possible manner, the apparatus 700 may include a processing unit 710 (ie, an example of a processor) and a transceiver unit 730. In some possible implementations, the processing unit 710 may also be referred to as a determination unit. In some possible implementations, the transceiver unit 730 may include a receiving unit and a sending unit.

[0194] In one implementation, the transceiver unit 730 may be implemented by a transceiver or a transceiver-related circuit or an interface circuit.

[0195] In one implementation, the device may further include a storage unit 720. In one possible implementation, the storage unit 720 is used to store instructions. In one implementation, the storage unit may also be used to store data or information. The storage unit 720 may be implemented by a memory.

[0196] In some possible designs, the processing unit 710 is used to execute the instructions stored in the storage unit 720, so that the apparatus 700 implements the steps performed by the terminal device in the above method. Alternatively, the processing unit 710 can be used to call the data of the storage unit 720, so that the apparatus 700 implements the steps performed by the terminal device in the above method.

[0197] In some possible designs, the processing unit 710 is used to execute the instructions stored in the storage unit 720, so that the apparatus 700 implements the steps performed by the access network device in the above method. Alternatively, the processing unit 710 can be used to call the data of the storage unit 720, so that the apparatus 700 implements the steps performed by the access network device in the above method.

[0198] For example, the processing unit 710, the storage unit 720, and the transceiver unit 730 can communicate with each other through the internal connection path to transmit control and / or data signals. For example, the storage unit 720 is used to store a computer program, and the processing unit 710 can be used to call and run the computer program from the storage unit 720 to control the transceiver unit 730 to receive signals and / or send signals, and complete the steps of the terminal device or access network device in the above method. The storage unit 720 can be integrated in the processing unit 710, or it can be set separately from the processing unit 710.

[0199] Optionally, if the apparatus 700 is a communication device (e.g., a terminal device or an access network device), the transceiver unit 730 includes a receiver and a transmitter. The receiver and the transmitter may be the same or different physical entities. When they are the same physical entities, they may be collectively referred to as transceivers.

[0200] When the device 700 is a terminal device or the device is an access network device or a core network device, the transceiver unit 730 may be a sending unit or a transmitter when sending information, and the transceiver unit 730 may be a receiving unit or a receiver when receiving information. The transceiver unit may be a transceiver, and the transceiver, transmitter or receiver may be a radio frequency circuit. When the device includes a storage unit, the storage unit is used to store computer instructions, and the processor is connected to the memory for communication. The processor executes the computer instructions stored in the memory, so that the device can execute method 200, method 500 or method 600. Among them, the processor may be a general-purpose central processing unit (CPU), a microprocessor, or an application-specific integrated circuit (ASIC).

[0201] Optionally, if the device 700 is a chip or a circuit, the transceiver unit 730 includes an input interface and an output interface.

[0202] When the device 700 is a chip, the transceiver unit 730 may be an input and / or output interface, a pin or a circuit, etc. The processing unit 710 may execute the computer-executable instructions stored in the storage unit so that the device may execute the method 200, the method 500 or the method 600. Optionally, the storage unit is a storage unit in the chip, such as a register, a cache, etc. The storage unit may also be a storage unit located outside the chip in the terminal, such as a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM), etc.

[0203] As an implementation, the function of the transceiver unit 730 may be implemented by a transceiver circuit or a dedicated chip for transceiver. The processing unit 710 may be implemented by a dedicated processing chip, a processing circuit, a processing unit or a general chip.

[0204] As another implementation method, it is possible to use a general-purpose computer to implement the communication device (e.g., terminal device, or access network device) provided in the embodiment of the present application. That is, the program code for implementing the functions of the processing unit 710 and the transceiver unit 730 is stored in the storage unit 720, and the general-purpose processing unit implements the functions of the processing unit 710 and the transceiver unit 730 by executing the code in the storage unit 720.

[0205] In some embodiments, the device 700 may be an access network device, and the access network device may be a first access network device, or a chip or circuit disposed in the first access network device. When the device 700 is a first access network device, or a chip or circuit disposed in the first access network device, the transceiver unit 730 is used to receive a first data packet and a first indication information from a core network device, and the first indication information is used to indicate the order of the first data packet in at least one data packet; the processing unit 710 is used to determine the first sequence number of the first protocol layer of the first data packet according to the first indication information; and the transceiver unit 730 is used to send the first data packet to the terminal device.

[0206] In one implementation, the first indication information includes at least one of the following information: a General Packet Radio Service Tunneling Protocol-User Plane GTP-U sequence number and a first service sequence number; the first service sequence number is set by the core network device or the data server, the first data packet is a data packet of the first service, and the at least one data packet is a data packet of the first service.

[0207] In an implementation manner, the first protocol layer includes at least one of the following: a service data adaptation protocol SDAP layer, a packet data convergence protocol PDCP layer, and a radio link control layer protocol RLC layer.

[0208] In one implementation, the processing unit 710 is further used to determine the starting sequence number of the first protocol layer of the first data packet according to the first indication information when any of the situations of the first protocol entity being newly created, the first protocol entity being rebuilt, and the first protocol entity being restored occurs.

[0209] In one implementation, the transceiver unit 730 is also used to: send second indication information to the terminal device, where the second indication information is used to indicate the sequence number of the first data packet belonging to the first service sent by the first access network device to the terminal device after the first protocol entity is newly established or the first protocol entity is rebuilt or the first protocol entity is restored.

[0210] In one implementation, the transceiver unit 730 is also used to: receive third indication information from the second access network device, the third indication information is used to instruct the first access network device to stop forwarding data packets to the second access network device; the processing unit 710 is used to stop forwarding data packets to the second access network device according to the third indication information.

[0211] In one implementation, the transceiver unit 307 is also used to: receive fourth indication information sent by the second access network device, the fourth indication information being used to indicate the sequence number of the first data packet forwarded by the first access network device to the second access network device; the processing unit 710 is used to forward the data packet to the second access network device according to the fourth indication information.

[0212] In one implementation, the transceiver unit 730 is also used to: receive fifth indication information sent by the second access network device, the fifth indication information includes a first sequence number N, the fifth indication information includes a second sequence number N, the second sequence number is used to indicate the sequence number of the first data packet belonging to the first service sent by the second access network device to the terminal device after the terminal device is switched, and the processing unit 710 is used to determine that when the protocol layer sequence number corresponding to the data packet successfully sent by the first access network device to the terminal device is N-1, stop sending data packets to the terminal device.

[0213] When the device 700 is configured in or is itself a first access network device, each module or unit in the device 700 can be used to execute each action or processing process performed by the first access network device in the above method. Here, in order to avoid redundancy, its detailed description is omitted.

[0214] In some embodiments, the apparatus 700 may be a terminal device, or a chip or circuit disposed in the terminal device. When the apparatus 700 is a terminal device, or a chip or circuit disposed in the terminal device, the transceiver unit 730 is used to receive second indication information sent by the first access network device, and the second indication information is used to indicate the sequence number of the first data packet belonging to the first service sent by the first access network device to the terminal device after the first protocol entity is newly established, the first protocol entity is rebuilt, or the first protocol entity is restored.

[0215] In one implementation, the transceiver unit 730 is also used to: when the first protocol entity is rebuilt or restored, send a request message to the first access network device, wherein the request message is used to request the first access network device to send the sequence number of the first data packet belonging to the first service sent by the first access network device to the terminal device after the first protocol entity is rebuilt or the first protocol entity is restored.

[0216] In one implementation, the transceiver unit 730 is also used to: send status report information of the data packet to the second access network device, and the status report information of the data packet is used to indicate the second access network device, the data packets successfully received and the data packets not successfully received by the terminal device, wherein the terminal device is switched from the first access network device to the second access network device.

[0217] When the device 700 is configured in or is itself a terminal device, each module or unit in the device 700 can be used to execute each action or processing process performed by the first terminal device in the above method. Here, in order to avoid redundancy, its detailed description is omitted.

[0218] In some embodiments, the device 700 may be an access network device, and the access network device may be a first access network device, or a chip or circuit disposed in the first access network device. When the device 700 is a first access network device, or a chip or circuit disposed in the first access network device, the transceiver unit 730 is used to receive a first data packet and a first indication information from a core network device, and the first indication information is used to indicate the order of the first data packet in at least one data packet; the processing unit 710 is used to determine the first sequence number of the first protocol layer of the first data packet according to the first indication information; and the transceiver unit 730 is used to send the first data packet to the terminal device.

[0219] In one implementation, the first indication information includes at least one of the following information: a General Packet Radio Service Tunneling Protocol-User Plane GTP-U sequence number and a first service sequence number; the first service sequence number is set by the core network device or the data server, the first data packet is a data packet of the first service, and the at least one data packet is a data packet of the first service.

[0220] In an implementation manner, the first protocol layer includes at least one of the following: a service data adaptation protocol SDAP layer, a packet data convergence protocol PDCP layer, and a radio link control layer protocol RLC layer.

[0221] In one implementation, the processing unit 710 is further used to determine the starting sequence number of the first protocol layer of the first data packet according to the first indication information when any of the situations of the first protocol entity being newly created, the first protocol entity being rebuilt, and the first protocol entity being restored occurs.

[0222] In one implementation, the transceiver unit 730 is also used to: send second indication information to the terminal device, where the second indication information is used to indicate the sequence number of the first data packet belonging to the first service sent by the first access network device to the terminal device after the first protocol entity is newly established or the first protocol entity is rebuilt or the first protocol entity is restored.

[0223] In one implementation, the transceiver unit 730 is further configured to: receive a data packet sent by the first access network device;

[0224] Among them, the second terminal device in the first access network device is switched from the first access network device to the second access network device, the first terminal device and the second terminal device both perform the first service, and the data packet sent by the first access network device is the data packet of the first service; when the second sequence number of the first protocol layer of the data packet currently being sent to the first terminal device is equal to or greater than the first sequence number of the first protocol layer of the data packet sent by the first access network device, a third indication information is sent to the first access network device, and the third indication information is used to instruct the first access network device to stop forwarding the data packet to the second access network device.

[0225] In one implementation, the transceiver unit 730 is also used to: receive status report information of the data packet sent by the second terminal device, the status report information of the data packet is used to indicate the second access network device, the data packets successfully received and the data packets not successfully received by the terminal device; and send fourth indication information to the first access network device based on the status report information, the fourth indication information is used to indicate the sequence number of the first data packet forwarded by the first access network device to the second access network device.

[0226] In one implementation, the transceiver unit 730 is also used to: send a fifth indication message to the first access network device, the fifth indication message including a second sequence number N, the fifth indication message including a second sequence number N, the second sequence number being used to indicate the sequence number of the first data packet belonging to the first service sent by the second access network device to the second terminal device after the switching of the second terminal device is completed.

[0227] When the device 700 is configured in or is itself a second access network device, each module or unit in the device 700 can be used to execute each action or processing process performed by the second access network device in the above method. Here, in order to avoid redundancy, its detailed description is omitted.

[0228] In some embodiments, the device 700 may be a core network device, or a chip or circuit disposed in the core network device. When the device 700 is a core network device, or a chip or circuit disposed in the core network device, the transceiver unit 730 is used to receive a first data packet sent by a data server; the transceiver unit 730 is used to send a second data packet and first indication information to a first access network device, the first indication information is used to indicate the order of the second data packet in at least one data packet sent by the core network device; the transceiver unit 730 is used to send a third data packet and second indication information to a second access network device, the first indication information is used to indicate the order of the third data packet in at least one data packet sent by the core network device, and the data of the second data packet and the data of the third data packet are the same as the data of the first data packet.

[0229] In one implementation, the first indication information includes at least one of the following information: a General Packet Radio Service Tunneling Protocol-User Plane GTP-U sequence number and a first service sequence number; the first service sequence number is set by the core network device or the data server, the first data packet is a data packet of the first service, and the at least one data packet is a data packet of the first service.

[0230] When the device 700 is configured in or is itself a core network device, each module or unit in the device 700 can be used to execute each action or processing process performed by the core network device in the above method. Here, in order to avoid redundancy, its detailed description is omitted.

[0231] For the concepts, explanations, detailed descriptions and other steps involved in the device 700 and related to the technical solution provided in the embodiment of the present application, please refer to the description of these contents in the aforementioned method or other embodiments, which will not be repeated here.

[0232] Fig. 9 This is a schematic diagram of the structure of a terminal device 800 provided in the present application. The terminal device 800 can execute the actions executed by the terminal device in the above method embodiment.

[0233] For ease of explanation, Fig. 9 Only the main components of the terminal device are shown. Fig. 9 As shown, the terminal device 800 includes a processor, a memory, a control circuit, an antenna, and an input and output device.

[0234] The processor is mainly used to process the communication protocol and communication data, as well as to control the entire terminal device, execute the software program, and process the data of the software program, for example, to support the terminal device to perform the actions described in the above-mentioned transmission precoding matrix indication method embodiment. The memory is mainly used to store software programs and data, for example, to store the codebook described in the above-mentioned embodiment. The control circuit is mainly used for conversion between baseband signals and radio frequency signals and processing of radio frequency signals. The control circuit and the antenna can also be called a transceiver, which is mainly used to send and receive radio frequency signals in the form of electromagnetic waves. Input and output devices, such as touch screens, display screens, keyboards, etc. are mainly used to receive data input by users and output data to users.

[0235] When the terminal device is turned on, the processor can read the software program in the storage unit, interpret and execute the instructions of the software program, and process the data of the software program. When data needs to be sent wirelessly, the processor performs baseband processing on the data to be sent, and outputs the baseband signal to the RF circuit. The RF circuit performs RF processing on the baseband signal and then sends the RF signal outward in the form of electromagnetic waves through the antenna. When data is sent to the terminal device, the RF circuit receives the RF signal through the antenna, converts the RF signal into a baseband signal, and outputs the baseband signal to the processor. The processor converts the baseband signal into data and processes the data.

[0236] Those skilled in the art will appreciate that for ease of description, Fig. 9 Only one memory and processor are shown. In an actual terminal device, there may be multiple processors and memories. The memory may also be referred to as a storage medium or a storage device, etc., which is not limited in the embodiments of the present application.

[0237] For example, the processor may include a baseband processor and a central processing unit. The baseband processor is mainly used to process the communication protocol and communication data, and the central processing unit is mainly used to control the entire terminal device, execute software programs, and process data of the software programs. Fig. 9 The processor in integrates the functions of the baseband processor and the central processing unit. Those skilled in the art will understand that the baseband processor and the central processing unit may also be independent processors, which are interconnected through technologies such as buses. Those skilled in the art will understand that the terminal device may include multiple baseband processors to adapt to different network standards, and the terminal device may include multiple central processing units to enhance its processing capabilities. The various components of the terminal device may be connected through various buses. The baseband processor may also be described as a baseband processing circuit or a baseband processing chip. The central processing unit may also be described as a central processing circuit or a central processing chip. The function of processing the communication protocol and communication data may be built into the processor, or may be stored in the storage unit in the form of a software program, and the processor executes the software program to implement the baseband processing function.

[0238] For example, in the embodiment of the present application, the antenna and the control circuit having the transceiver function may be regarded as the transceiver unit 810 of the terminal device 800, and the processor having the processing function may be regarded as the processing unit 820 of the terminal device 800. Fig. 9 As shown, the terminal device 800 includes a transceiver unit 810 and a processing unit 820. The transceiver unit may also be referred to as a transceiver, a transceiver, a transceiver device, etc. Optionally, the device used to implement the receiving function in the transceiver unit 810 may be regarded as a receiving unit, and the device used to implement the sending function in the transceiver unit 810 may be regarded as a sending unit, that is, the transceiver unit includes a receiving unit and a sending unit. Exemplarily, the receiving unit may also be referred to as a receiver, a receiver, a receiving circuit, etc., and the sending unit may be referred to as a transmitter, a transmitter, or a transmitting circuit, etc.

[0239] Fig.10 A structural diagram of an access network device 900 provided in an embodiment of the present application can be used to implement the functions of the access device (e.g., the first access network device, the second access network device, or the third access network device) in the above method. The access network device 900 includes one or more radio frequency units, such as a remote radio unit (RRU) 910 and one or more baseband units (BBU) (also referred to as digital units, digital units, DU) 920. The RRU 910 can be referred to as a transceiver unit, a transceiver, a transceiver circuit, or a transceiver, etc., and it can include at least one antenna 911 and a radio frequency unit 912. The RRU 910 part is mainly used for the transmission and reception of radio frequency signals and the conversion of radio frequency signals and baseband signals, for example, for sending the signaling message described in the above embodiment to the terminal device. The BBU 920 part is mainly used for baseband processing, controlling the base station, etc. The RRU 910 and the BBU 920 can be physically arranged together or physically separated, that is, a distributed base station.

[0240] The BBU 920 is the control center of the base station, which can also be called a processing unit, and is mainly used to complete baseband processing functions, such as channel coding, multiplexing, modulation, spread spectrum, etc. For example, the BBU (processing unit) 920 can be used to control the base station 40 to execute the operation process of the network device in the above method embodiment.

[0241] In one example, the BBU920 may be composed of one or more single boards, and multiple single boards may jointly support a wireless access network of a single access standard (such as an LTE system or a 5G system), or may respectively support wireless access networks of different access standards. The BBU920 also includes a memory 921 and a processor 922. The memory 921 is used to store necessary instructions and data. For example, the memory 921 stores the codebook in the above embodiment, etc. The processor 922 is used to control the base station to perform necessary actions, such as controlling the base station to execute the operation process of the network device in the above method embodiment. The memory 921 and the processor 922 can serve one or more single boards. In other words, a memory and a processor can be set separately on each single board. It is also possible that multiple single boards share the same memory and processor. In addition, necessary circuits can also be set on each single board.

[0242] In a possible implementation, with the development of system-on-chip (SoC) technology, all or part of the functions of parts 920 and 910 can be implemented by SoC technology, for example, by a base station function chip, which integrates devices such as a processor, a memory, and an antenna interface, and the program of the base station-related functions is stored in the memory, and the processor executes the program to implement the relevant functions of the base station. Optionally, the base station function chip can also read the memory outside the chip to implement the relevant functions of the base station.

[0243] It should be understood that Fig.10 The structure of the access network device in the example is only one possible form and should not constitute any limitation to the embodiments of the present application. The present application does not exclude the possibility of other forms of base station structures that may appear in the future.

[0244] It should be understood that in the embodiments of the present application, the processor may be a central processing unit (CPU), and the processor may also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0245] It should also be understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0246] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented by software, the above embodiments can 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 or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that contains one or more available media sets. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state hard disk.

[0247] An embodiment of the present application also provides a computer-readable medium on which a computer program is stored. When the computer program is executed by a computer, it implements the steps performed by the terminal device in any of the above embodiments, or the steps performed by the first access network device, or the steps performed by the second access network device, or the steps performed by the core network device.

[0248] An embodiment of the present application also provides a computer program product, which, when executed by a computer, implements the steps executed by the terminal device in any of the above embodiments, or the steps executed by the first access network device, or the steps executed by the second access network device, or the steps executed by the core network device.

[0249] The embodiment of the present application also provides a system chip, which includes: a communication unit and a processing unit. The processing unit may be, for example, a processor. The communication unit may be, for example, a communication interface, an input / output interface, a pin or a circuit. The processing unit may execute computer instructions to enable the chip in the communication device to execute the steps performed by the terminal device provided in the embodiment of the present application, or the steps performed by the first access network device, or the steps performed by the second access network device, or the steps performed by the core network device.

[0250] Optionally, the computer instructions are stored in a storage unit.

[0251] According to the method provided in an embodiment of the present application, an embodiment of the present application also provides a communication system, which includes the aforementioned first access network device, second access network device, core network device and terminal device.

[0252] The various embodiments in this application may be used independently or in combination, which is not limited here.

[0253] In addition, various aspects or features of the present application can be implemented as methods, devices or products using standard programming and / or engineering techniques. The term "product" used in this application covers computer programs that can be accessed from any computer-readable device, carrier or medium. For example, computer-readable media may include, but are not limited to: magnetic storage devices (e.g., hard disks, floppy disks or tapes, etc.), optical disks (e.g., compact discs (CDs), digital versatile discs (DVDs), etc.), smart cards and flash memory devices (e.g., erasable programmable read-only memory (EPROM), cards, sticks or key drives, etc.). In addition, the various storage media described herein may represent one or more devices and / or other machine-readable media for storing information. The term "machine-readable medium" may include, but is not limited to, wireless channels and various other media capable of storing, containing and / or carrying instructions and / or data.

[0254] It should be understood that "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent three situations: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the previously associated objects are in an "or" relationship. "At least one" means one or more; "at least one of A and B" is similar to "A and / or B", describing the association relationship of associated objects, indicating that three relationships may exist. For example, at least one of A and B can represent three situations: A exists alone, A and B exist at the same time, and B exists alone.

[0255] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0256] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0257] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0258] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0259] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0260] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0261] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A communication method, characterized in that: include: Receiving a first data packet and a first core network sequence number from a core network device, where the first core network sequence number is set by the core network device, and the first core network sequence number is used to indicate an order of the first data packet in at least one data packet; Determine a first sequence number of a first protocol layer of the first data packet according to the core network sequence number; The first data packet is sent to the terminal device.

2. The method according to claim 1, characterized in that The at least one data packet is a data packet of a first service, wherein the first service is a multicast service.

3. The method according to claim 1 or 2, characterized in that: The first sequence number of the first protocol layer of the first data packet is used to sort or perform duplication detection on the first data packet.

4. The method according to any one of claims 1 to 3, characterized in that The first protocol layer is a Packet Data Convergence Protocol PDCP layer.

5. The method according to any one of claims 1 to 4, characterized in that Determining a first sequence number of a first protocol layer of the first data packet according to the first core network sequence number includes: Determine that the first sequence number of the first protocol layer of the first data packet is equal to the value of the first core network sequence number.

6. The method according to any one of claims 1 to 5, characterized in that The second core network sequence number corresponding to the second data packet has the same value as the first core network sequence number, wherein the second data packet is a data packet sent by the core network device to the second access network device, and the data in the second data packet is the same as the data in the first data packet.

7. The method according to claim 1, characterized in that The method further comprises: Instruct the terminal device to switch from the first access network device to the second access network device.

8. The method according to claim 6 or 7, characterized in that: A data packet is sent to the second access network device, wherein the sequence number of the first protocol layer corresponding to the data packet is smaller than the sequence number of the first protocol layer corresponding to the data packet received by the second access network device from the core network device.

9. The method according to any one of claims 1 to 8, characterized in that The core network equipment is a user plane function.

10. The method according to any one of claims 1 to 9, characterized in that The method further comprises: When any of the situations of newly creating the first protocol entity, reconstructing the first protocol entity and recovering the first protocol entity occurs, the starting sequence number of the first protocol layer of the first received data packet is set according to the first core network sequence number.

11. The method according to any one of claims 1 to 10, characterized in that The method further comprises: Sending second indication information to the terminal device, wherein the second indication information is used to indicate the sequence number of the first data packet belonging to the first service sent by the first access network device to the terminal device after the first protocol entity is newly established or the first protocol entity is rebuilt or the first protocol entity is restored.

12. A communication method, characterized in that: include: Sending a first data packet and a first core network sequence number to a first access network device, where the first core network sequence number is used to indicate the order of the first data packet in at least one data packet, and the first core network sequence number is used to determine a first sequence number of a first protocol layer of the first data packet; Sending a second data packet and a second core network sequence number to a second access network device, where the second core network sequence number is used to indicate the order of the second data packet in at least one data packet, and the second core network sequence number is used to determine a second sequence number of a first protocol layer of the second data packet; The data of the second data packet is the same as the data of the first data packet, and the value of the first core network sequence number is equal to the value of the second core network sequence number.

13. The method according to claim 12, characterized in that The first core network serial number and the second core network serial number are set for the core network device.

14. The method according to claim 12 or 13, characterized in that The at least one data packet is a data packet of a first service, wherein the first service is a multicast service.

15. The method according to any one of claims 12 to 14, characterized in that: The first sequence number of the first protocol layer is equal to the first core network sequence number.

16. The method according to any one of claims 12 to 14, characterized in that: The second sequence number of the first protocol layer is equal to the second core network sequence number.

17. The method according to any one of claims 12 to 16, characterized in that: The first protocol layer is a Packet Data Convergence Protocol PDCP layer.

18. The method according to any one of claims 12 to 16, characterized in that: The first sequence number of the first protocol layer or the second sequence number of the first protocol layer is used to sort or duplicate the first data packet.

19. The method according to any one of claims 12 to 18, characterized in that: The core network equipment is a user plane function.

20. A communication device, characterized in that: include: A transceiver unit, configured to receive a first data packet and a first core network sequence number from a core network device, where the first core network sequence number is set by the core network device, and the first core network sequence number is used to indicate an order of the first data packet in at least one data packet; A processing unit, configured to determine a first sequence number of a first protocol layer of the first data packet according to the core network sequence number; The transceiver unit is further configured to send the first data packet to a terminal device.

21. The communication device according to claim 20, characterized in that: The at least one data packet is a data packet of a first service, wherein the first service is a multicast service.

22. The communication device according to claim 20 or 21, characterized in that: The first sequence number of the first protocol layer of the first data packet is used to sort or perform duplication detection on the first data packet.

23. The communication device according to any one of claims 20 to 22, characterized in that: The first protocol layer is a Packet Data Convergence Protocol PDCP layer.

24. The communication device according to any one of claims 20 to 23, characterized in that: Determining a first sequence number of a first protocol layer of the first data packet according to the first core network sequence number includes: Determine that the first sequence number of the first protocol layer of the first data packet is equal to the value of the first core network sequence number.

25. The communication device according to any one of claims 20 to 24, characterized in that: The second core network sequence number corresponding to the second data packet has the same value as the first core network sequence number, wherein the second data packet is a data packet sent by the core network device to the second access network device, and the data in the second data packet is the same as the data in the first data packet.

26. The communication device according to claim 25, characterized in that The transceiver unit is also used to instruct the terminal device to switch from the first access network device to the second access network device.

27. The communication device according to claim 25 or 26, characterized in that: The transceiver unit is also used to send a data packet to the second access network device, and the serial number of the first protocol layer corresponding to the data packet is smaller than the serial number of the first protocol layer corresponding to the data packet received by the second access network device from the core network device.

28. The communication device according to any one of claims 20 to 27, characterized in that: The core network equipment is a user plane function.

29. The communication device according to any one of claims 20 to 28, characterized in that: When any of the situations of newly creating the first protocol entity, reconstructing the first protocol entity and recovering the first protocol entity occurs, the processing unit is further used to set the starting sequence number of the first protocol layer of the first received data packet according to the first core network sequence number.

30. The communication device according to any one of claims 20 to 29, characterized in that: The transceiver unit is also used to send second indication information to the terminal device, wherein the second indication information is used to indicate the sequence number of the first data packet belonging to the first service sent by the first access network device to the terminal device after the first protocol entity is newly established or the first protocol entity is rebuilt or the first protocol entity is restored.

31. A communication device, characterized in that: include: A transceiver unit, configured to send a first data packet and a first core network sequence number to a first access network device, wherein the first core network sequence number is used to indicate an order of the first data packet in at least one data packet, and the first core network sequence number is used to determine a first sequence number of a first protocol layer of the first data packet; The transceiver unit is further used to send a first data packet and a first core network sequence number to the first access network device, where the first core network sequence number is used to indicate the order of the first data packet in at least one data packet, and the first core network sequence number is used to determine a first sequence number of a first protocol layer of the first data packet; The data of the second data packet is the same as the data of the first data packet, and the value of the first core network sequence number is equal to the value of the second core network sequence number.

32. The communication device according to claim 31, characterized in that The first core network serial number and the second core network serial number are set for the core network device.

33. The communication device according to claim 31 or 32, characterized in that: The at least one data packet is a data packet of a first service, wherein the first service is a multicast service.

34. The communication device according to any one of claims 31 to 33, characterized in that: The first sequence number of the first protocol layer is equal to the first core network sequence number.

35. The communication device according to any one of claims 31 to 33, characterized in that: The second sequence number of the first protocol layer is equal to the second core network sequence number.

36. The communication device according to any one of claims 31 to 35, characterized in that: The first protocol layer is a Packet Data Convergence Protocol PDCP layer.

37. The communication device according to any one of claims 31 to 35, characterized in that: The first sequence number of the first protocol layer or the second sequence number of the first protocol layer is used to sort or duplicate the first data packet.

38. The communication device according to any one of claims 31 to 37, characterized in that: The core network equipment is a user plane function.

39. A communication system, comprising access network equipment and core network equipment, wherein: The core network device is used to send a first data packet and a first core network sequence number to a first access network device, where the first core network sequence number is used to indicate the order of the first data packet in at least one data packet; The access network device is used to receive the first data packet and the first core network sequence number; The access network device is further used to determine a first sequence number of a first protocol layer of the first data packet according to the core network sequence number; The access network device is also used to send the first data packet to the terminal device.

40. A communication method, characterized in that: The method comprises: The core network device sends a first data packet and a first core network sequence number to the first access network device, where the first core network sequence number is used to indicate the order of the first data packet in at least one data packet; The access network device receives the first data packet and the first core network sequence number; The access network device determines a first sequence number of a first protocol layer of the first data packet according to the core network sequence number; The access network device sends the first data packet to the terminal device.

41. A communication device, comprising a processor, wherein the processor is connected to a memory, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the device performs the method as claimed in any one of claims 1 to 11.

42. A communication device, comprising a processor, wherein the processor is connected to a memory, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the device performs the method as claimed in any one of claims 12 to 17.

43. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed, the method according to any one of claims 1 to 10, or any one of claims 11 to 13, or any one of claims 14 to 19 is implemented.

44. A communication system, comprising the communication device described in any one of claims 20-30 and the communication device described in any one of claims 31-36.

45. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the method according to any one of claims 1 to 11 is implemented.

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