CN115314953A - Method of cell handover for relay terminal device and associated communication apparatus, medium and chip - Google Patents

Abstract

Embodiments of the present disclosure provide a cell handover method for relay terminal equipment and an associated communication apparatus, medium, and chip. In the embodiment of the present disclosure, the relay terminal device relays the communication between the remote terminal device and the source network device. The relay terminal device receives an instruction to switch to the target network device from the source network device. After the relay terminal device is switched to the target network device, the relay device sends the data buffered at the relay terminal device to the remote terminal device and/or the target network device. A user plane tunnel is established between the source network device and the target network device for transmitting data associated with the remote terminal device. In this way, data loss of the remote terminal equipment during the switching process of the relay terminal equipment is avoided.

Description

Method for cell handover of relay terminal equipment and associated communication device, intermediary quality and chips

technical field

The present disclosure relates to the field of communication, and more particularly, to cell handover of relay terminal equipment and associated communication devices, media and chips.

Background technique

In order to support direct communication between devices to increase system capacity without transit through the network, sidelink communication link technology has been introduced, also known as sidelink or sidechain, and the corresponding interface is called PC5 interface. The sidelink was first introduced with the device-to-device (Devcie-to-Device, D2D) communication technology, and later extended to the vehicle-to-everything (V2X). D2D communication is flexible in transmission form, can reduce transmission delay, and can improve system capacity on the basis of cellular network, so it is one of the key technologies of 5G New Radio (New Radio, NR). In order to improve network system performance, such as coverage enhancement and capacity enhancement, based on sidelink communication, a user equipment to network relay (UE-to-Network Relay, U2N Relay) communication technology is proposed. In order to improve user experience, operators can deploy some relay terminal devices to assist other terminals in relaying data, thereby improving coverage.

Contents of the invention

Exemplary embodiments of the present disclosure provide a solution for cell handover of a relay terminal device in a communication system.

In a first aspect of the present disclosure, a method for communication is provided. In the method, the relay terminal device relays the communication between the remote terminal device and the source network device. The relay terminal device receives the first indication from the source network device. The first indication is used to instruct the relay terminal device to switch from the source network device to the target network device. The relay terminal device performs handover based on the first indication. The relay terminal device sends the first data from the source network device to the remote terminal device. In this way, the loss of data packets of the remote terminal device during the switching process of the relay terminal device is avoided.

In some embodiments, the method further includes: after the relay terminal device receives the first indication, the relay terminal device sends the second indication to the remote terminal device. The second indication is used to instruct the remote terminal device to stop sending data to the source network device. In this manner, the remote terminal device is prevented from still sending data to the relay terminal device after the relay terminal device is switched.

In some embodiments, the method further includes: after the relay terminal device sends the first data, the relay terminal device releases the sidelink with the remote terminal device. In this way, the timely release of the sidelink is realized, and unnecessary resource occupation is avoided.

In some embodiments, the method includes: the relay terminal device sends the second data to the remote terminal device, and the second data comes from the remote terminal device. In this way, UL data transmission buffered at the relay terminal device after handover is achieved.

In some embodiments, the method further includes: the relay terminal device sending the second data to the remote terminal device includes: the relay terminal device sending the second data through a side link between the relay terminal device and the remote terminal device second data. In this way, multiplexing of links is achieved.

In some embodiments, the method further includes: before the relay terminal device sends the second data, the relay terminal device adds an identifier to the second data, where the identifier is used to indicate that the second data comes from the remote terminal device. In this way, differentiation of data of different directions is achieved.

In some embodiments, the method further includes: the relay terminal device establishes a first sidelink bearer, where the first sidelink bearer is used for transmission of the second data. In this way, adding complexity to the packet header is avoided.

In some embodiments, the method further includes: after the relay terminal device sends the first data and the second data, the relay terminal device releases the sidelink with the remote terminal device. In this way, the timely release of the sidelink is realized, and unnecessary resource occupation is avoided.

In a second aspect of the present disclosure, a method for communication is provided. In the method, the relay terminal device relays the communication between the remote terminal device and the source network device. The relay terminal device receives a first indication from the source network device, where the first indication is used to instruct the relay terminal device to switch from the source network device to the target network device. The relay terminal device performs handover based on the first indication. The relay terminal device sends third data to the target network device, where the third data includes data received from the remote terminal device before receiving the first indication. In this way, the loss of data packets of the remote terminal device during the switching process of the relay terminal device is avoided.

In some embodiments, the method further includes: the third data further includes data from the source network device. In this way, the transmission of the data buffered at the relay terminal device is realized.

In some embodiments, the method further includes: the relay terminal device establishes one or more radio link control layer bearers based on the bearer configuration in the first indication; and wherein the relay terminal device sends the third data to the target network device The method includes: the relay terminal device sends the third data through one or more radio link control layer bearers. In this way, the transmission of the data buffered at the relay terminal device is realized.

In some embodiments, the method further includes: if it is determined that multiple remote terminal devices multiplex the radio link control layer bearer, before the relay terminal device sends the third data, the relay terminal device adds The identification of the remote terminal equipment and the identification of the bearer of the remote terminal equipment; or if it is determined that multiple bearers of a remote terminal equipment are multiplexed with the radio link control layer bearer, before the relay terminal equipment sends the third data, the relay The terminal device adds the identifier of the bearer of the remote terminal device to the third data. In this way, the distinction between the bearer of the remote terminal device carrying data and the terminal device is realized, and unnecessary addition of headers is avoided.

In some embodiments, the method further includes: after the relay terminal device sends the third data, the relay terminal device sends a third indication to the target network device, the third indication is used to indicate the completion of the transmission of the third data . In this manner, the remote terminal device is prevented from still sending data to the relay terminal device after the relay terminal device is switched.

In a third aspect of the present disclosure, a method for communicating is provided. In this method, the source network device sends a switching request to the target network device, the switching request is used to switch the relay terminal device to the target network device, and the switching request includes the identification of the remote terminal device and the information of the radio bearer corresponding to the remote terminal device The mapping relationship between identifiers, the relay terminal device relays the communication between the remote terminal device and the source network device; the source network device sends a first indication to the relay terminal device, and the first indication is used to indicate the relay terminal The device is switched from the source network device to the target network device; and the source network device receives third data from the target network device, the third data includes data from the remote terminal device. In this way, the loss of data packets of the remote terminal device during the switching process of the relay terminal device is avoided.

In some embodiments, the third data also includes data from the source network device, wherein the method further includes: the source network device respectively receives from the target network device the data from the remote terminal device and the data from the source network through different user plane tunnels. The data of the device; or the source network device receives data from the remote terminal device and data from the source network device from the target network device through the same user plane tunnel, and the third data includes an identification to distinguish the data from the remote terminal device and data from source network devices. In this way, the distinction between the bearer of the remote terminal device carrying data and the terminal device is realized, and unnecessary addition of headers is avoided.

In some embodiments, the method further includes: the source network device establishes a user plane tunnel with the target network device based on the mapping relationship for transmission of the third data; wherein the source network device establishes the user plane tunnel including the following: Item: the source network device configures a user plane tunnel that is multiplexed among multiple remote terminal devices; or the source network device configures a user plane tunnel that is multiplexed among multiple radio bearers of a remote terminal device; or the source network The device configures user plane tunnels separately for each radio bearer. In this way, multiplexing of tunnels is realized, and waste of resources is avoided.

In some embodiments, the third data includes the following item: if it is determined that the user plane tunnel is multiplexed among multiple remote terminal devices, the third data includes the identifier of the remote terminal device and the corresponding or if it is determined that the user plane tunnel is multiplexed among multiple radio bearers of a remote terminal device, the third data includes the identification of the radio bearer corresponding to the remote terminal device; or if it is determined that the user plane Tunnels are not multiplexed among multiple remote terminal devices, and the third data does not include the identifier of the remote terminal device and the identifier of the radio bearer corresponding to the remote terminal device. In this way, the distinction between the bearer of the remote terminal device carrying data and the terminal device is realized, and unnecessary addition of headers is avoided.

In some embodiments, the method further includes: the source network device transfers the third data to the remote terminal device based on the identifier of the remote terminal device carried by the third data and the identifier of the radio bearer corresponding to the remote terminal device The corresponding end-to-end packet data aggregation layer.

In some embodiments, the method further includes: the source network device receiving a fourth indication from the target network device, the fourth indication being used to indicate completion of the third data transmission. In this way, timely resource release can be achieved.

In a fourth aspect of the present disclosure, a method for communicating is provided. In this method, the target network device receives a handover request from the source network device, and the handover request is used to switch the relay terminal device to the target network device, and the relay terminal device performs communication between the remote terminal device and the source network device Relay; the target network device receives third data from the relay terminal device, the third data includes data from the remote terminal device; and the target network device sends the third data to the source network device. In this way, the loss of data packets of the remote terminal device during the switching process of the relay terminal device is avoided.

In some embodiments, the third data also includes data from the source network device. In this way, the transmission of the data buffered at the relay terminal device is realized.

In some embodiments, the target network device receiving the third data from the relay terminal device includes: the target network device receiving the third data from the relay terminal device through a radio link control layer bearer; and wherein: if it is determined that the radio link control layer bearer Multiplexed among multiple remote terminal equipments, the third data includes the identification of the remote terminal equipment and the identification of the radio bearer corresponding to the remote terminal equipment; or if it is determined that the radio link control layer is carried by a remote terminal The multiple radio bearers of the device are multiplexed, and the third data includes the identifier of the radio bearer corresponding to the remote terminal device. In this way, the distinction between the bearer of the remote terminal device carrying data and the terminal device is realized, and unnecessary addition of headers is avoided.

In some embodiments, the method further includes: the target network device establishes a user plane tunnel with the source network device; and the target network device sends the third data to the source network device through the user plane tunnel. In some embodiments, the method further includes: the target network device performs at least one of the following based on the multiplexing of the radio link control layer bearer and the multiplexing of the user plane tunnel: retaining the identity and the identity of the remote terminal device in the third data /or the identification of the radio bearer of the remote terminal equipment; add the identification of the remote terminal equipment and/or the identification of the radio bearer of the remote terminal equipment to the third data; or delete the identification and the identification of the remote terminal equipment from the third data /or the identification of the radio bearer of the remote terminal equipment; or if it is determined that the radio link control layer bearer is not to be multiplexed among multiple remote terminal equipments, the third data does not include the identification of the remote terminal equipment and the information related to the remote terminal equipment The identifier of the radio bearer corresponding to the terminal device. In this way, multiplexing of tunnels is realized, and waste of resources is avoided.

In some embodiments, the method further includes: after the target network sends the third data, the target network sends a fifth indication to the source network device, where the fifth indication is used to indicate the completion of the transmission of the third data. In this way, timely resource release can be achieved.

In a fifth aspect of the present disclosure, a method for communicating is provided. In this method, the relay terminal device relays the communication between the remote terminal device and the source network device; the relay terminal device receives a sixth indication from the source network device, and the sixth indication is used to instruct the remote terminal device to perform Reselection of a cell or a relay terminal device; the relay terminal device sends a sixth indication to the remote terminal device; the relay terminal device sends sixth data from the remote terminal device to the source network device.

In some embodiments, the method further includes: after the relay terminal device sends the sixth data, the relay terminal device sends a seventh indication to the source network device, the seventh indication is used to indicate the completion of the transmission of the sixth data . In this way, a timely release of the link is achieved.

In some embodiments, the method further includes: the relay terminal device sends the seventh data from the source network device to the remote terminal device; and after the relay terminal device sends the seventh data, the relay terminal device releases the connection with the remote Sidelinks between end-to-end devices. In this way, timely release of the sidelink is achieved.

In some embodiments, the sixth indication includes an identity of a target cell of the remote terminal device or a target relay terminal device. In this way, the switching time of the remote terminal equipment is shortened.

In a sixth aspect of the present disclosure, a method for communication is provided. In this method, the relay terminal device relays the communication between the remote terminal device and the source network device; the relay terminal device receives a first indication from the source network device, and the first indication is used to instruct the relay terminal device to The source network device switches to the target network device; the relay terminal device establishes a connection with the target network device based on the first indication while maintaining the connection with the source network device; and the relay terminal device sends the first instruction from the source network device to the remote terminal device. a data. In this way, the loss of data packets of the remote terminal device during the switching process of the relay terminal device is avoided.

In some embodiments, the method further includes: after the relay terminal device receives the first indication, the relay terminal device sends a second indication to the remote terminal device, and the second indication is used to instruct the remote terminal device to stop sending The source network device sends the data. In this manner, the remote terminal device is prevented from still sending data to the relay terminal device after the relay terminal device is switched.

In some embodiments, the method further includes: after the relay terminal device sends the first data, the relay terminal device releases the sidelink with the remote terminal device. In this way, timely release of the sidelink is achieved.

In some embodiments, the method further includes: the relay terminal device sending third data to the source network device, where the third data includes data from the remote terminal device. In this way, the transmission of the data buffered at the relay terminal device is realized.

In some embodiments, the method further includes: after the relay terminal device sends the third data, the relay terminal device sends a third indication to the source network device, where the third indication is used to indicate the completion of the transmission of the third data . In this way, timely release of the sidelink is achieved.

In a seventh aspect of the present disclosure, a method for communication is provided. In this method, the source network device determines that the relay terminal device will perform cell handover; the source network device sends a sixth indication to the relay terminal device, and the sixth indication is used to instruct the remote terminal device to perform cell or relay terminal device switching. selecting; and the source network device receives sixth data from the remote terminal device from the relay terminal device. In this way, the loss of data packets of the remote terminal device during the switching process of the relay terminal device is avoided.

In some embodiments, the method further includes: after the relay terminal device sends the sixth data, the source network device receives a seventh indication from the relay terminal device, where the seventh indication is used to indicate the completion of the transmission of the sixth data. In this way, timely release of the sidelink is achieved.

In some embodiments, the sixth indication includes an identity of a target cell of the remote terminal device or a target relay terminal device. In this way, the switching time of the remote terminal equipment is shortened.

In an eighth aspect of the present disclosure, a method for communicating is provided. In this method, the source network device sends a switching request to the target network device, the switching request is used to switch the relay terminal device to the target network device, and the switching request includes the identification of the remote terminal device and the information of the radio bearer corresponding to the remote terminal device The mapping relationship between identifiers, the relay terminal device relays the communication between the remote terminal device and the source network device; the source network device sends a first indication to the relay terminal device, and the first indication is used to indicate the relay terminal The device is switched from the source network device to the target network device; and the source network device receives third data from the relay terminal device, where the third data includes data from the remote terminal device. In this way, the loss of data packets of the remote terminal device during the switching process of the relay terminal device is avoided.

In some embodiments, the method further includes: after the relay terminal device sends the third data, the source network device receives a third indication from the relay terminal device, where the third indication is used to indicate the completion of the transmission of the third data; And the source network device releases the radio resource control connection with the relay terminal device. In this way, timely release of the sidelink is achieved.

In a ninth aspect of the present disclosure, a method for communicating is provided. In this method, the remote terminal device receives a sixth indication from the relay terminal device, and the sixth indication is used to instruct the remote terminal device to reselect a cell or a relay terminal device, and the remote terminal device accesses the to the source network device; the remote terminal device receives the seventh data from the source network device from the relay terminal device; and the relay terminal device releases the sidelink with the remote terminal device. In this way, the loss of data packets of the remote terminal device during the switching process of the relay terminal device is avoided.

In some embodiments, the sixth indication includes an identity of a target cell of the remote terminal device or a target relay terminal device. In this way, the switching time of the remote terminal equipment is shortened.

In a tenth aspect of the present disclosure, a chip is provided. The chip is configured to execute the operations of the method in any possible implementation manner according to the first aspect to the ninth aspect above.

In an eleventh aspect of the present disclosure, a terminal device is provided. The terminal device comprises: at least one processing unit; and at least one memory, the at least one memory being coupled to the at least one processing unit and storing instructions for execution by the at least one processing unit, the instructions causing the terminal device when executed by the at least one processing unit Implement the method in any possible implementation manner according to the first aspect, the second aspect, the fifth aspect, the sixth aspect, and the ninth aspect.

In a twelfth aspect of the present disclosure, a network device is provided. The network device includes: at least one processing unit; and at least one memory, the at least one memory being coupled to the at least one processing unit and storing instructions for execution by the at least one processing unit, the instructions causing the network device when executed by the at least one processing unit Implement the method in any possible implementation manner according to the third aspect, the fourth aspect, the seventh aspect, and the eighth aspect.

In a thirteenth aspect of the present disclosure, a computer program product is provided. The computer program product is tangibly stored on a computer-readable medium and includes computer-executable instructions. When executed, the computer-executable instructions cause the device to implement the The operation of the method.

In a fourteenth aspect of the present disclosure, a communication device is provided. The communication device includes components for implementing the method in any possible implementation manners according to the first aspect, the second aspect, the fifth aspect, the sixth aspect, and the ninth aspect.

In a fifteenth aspect of the present disclosure, a communication device is provided. The communications device includes components for implementing the method in any possible implementation manners according to the third aspect, the fourth aspect, the seventh aspect, and the eighth aspect.

In a sixteenth aspect of the present disclosure, a communication system is provided. The communication system includes components for implementing the method in any possible implementation manner according to the first aspect, the second aspect, the fifth aspect, the sixth aspect, and the ninth aspect, and for implementing the method according to the third aspect, A component of a method in any possible implementation manner of the fourth aspect, the seventh aspect, and the eighth aspect.

Description of drawings

The features, advantages and other aspects of various implementations of the present disclosure will become more apparent with reference to the following detailed description when taken in conjunction with the accompanying drawings. Several implementations of the present disclosure are shown here by way of illustration and not limitation, in the accompanying drawings:

Figure 1 shows a schematic block diagram for a device-to-network relay communication architecture;

Figure 2 shows a schematic block diagram of a communication environment in which embodiments of the present disclosure may be;

FIG. 3 shows an interactive signaling diagram of a communication process according to some embodiments of the present disclosure;

4A and 4B show schematic block diagrams of headers of data packets according to embodiments of the present disclosure;

Fig. 5 shows an interactive signaling diagram of a communication process according to other embodiments of the present disclosure;

Fig. 6 shows an interactive signaling diagram of a communication process according to some other embodiments of the present disclosure;

Fig. 7 shows an interactive signaling diagram of a communication process according to some further embodiments of the present disclosure;

FIG. 8 shows an interactive signaling diagram of a communication process according to some embodiments of the present disclosure;

FIG. 9A and FIG. 9B respectively show interactive signaling diagrams of the communication process according to some embodiments of the present disclosure;

Fig. 10 shows a flowchart implemented at a relay terminal device according to some embodiments of the present disclosure;

Fig. 11 shows a flowchart implemented at a relay terminal device according to other embodiments of the present disclosure;

Figure 12 shows a flowchart implemented at a source network device according to some embodiments of the present disclosure;

FIG. 13 shows a flowchart implemented at a target network device according to some embodiments of the present disclosure;

Fig. 14 shows a flowchart implemented at a relay terminal device according to some other embodiments of the present disclosure;

Fig. 15 shows a flow chart implemented at a relay terminal device according to some further embodiments of the present disclosure;

Fig. 16 shows a flow chart implemented at the source network device according to still other embodiments of the present disclosure;

Fig. 17 shows a flow chart implemented at the source network device according to some further embodiments of the present disclosure;

Fig. 18 shows a flowchart implemented at a remote terminal device according to some embodiments of the present disclosure;

19A to 19D show schematic block diagrams of communication devices according to some embodiments of the present disclosure; and

Figure 20 shows a simplified block diagram of an example device suitable for implementing embodiments of the present disclosure.

In the various drawings, the same or similar reference numerals denote the same or similar elements.

Detailed ways

Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the drawings, it should be understood that the disclosure may be embodied in various forms and should not be construed as limited to the embodiments set forth herein; A more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are for exemplary purposes only, and are not intended to limit the protection scope of the present disclosure.

In the description of the embodiments of the present disclosure, the term "comprising" and its similar expressions should be interpreted as an open inclusion, that is, "including but not limited to". The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be read as "at least one embodiment". The terms "first", "second", etc. may refer to different or the same object. Other definitions, both express and implied, may also be included below.

Embodiments of the present disclosure may be implemented according to any suitable communication protocol, including but not limited to, cellular communication protocols such as Fourth Generation (4G) and Fifth Generation (5G), such as the Institute of Electrical and Electronics Engineers (Institute of Electrical and Electronics Engineers, IEEE) 802.11 and other wireless local area network communication protocols, and/or any other protocols currently known or developed in the future. The technical solutions of the embodiments of the present disclosure are applied to any appropriate communication system, for example: General Packet Radio Service (General Packet Radio Service, GPRS), Long Term Evolution (Long Term Evolution, LTE) system, Frequency Division Duplex (Frequency Division Duplex, FDD ) system, Time Division Duplex (TDD), Universal Mobile Telecommunications Service (UMTS), Narrowband Internet Of Things (NB-IoT) communication system, the future fifth generation (5G) System or New Radio (New Radio, NR), etc.

For the purpose of illustration, embodiments of the present disclosure will be described below in the context of a 5G 3rd Generation Partnership Project (3rd Generation Partnership Project, 3GPP) communication system. However, it should be understood that the embodiments of the present disclosure are not limited to the 3GPP communication system applied to 5G, but can be applied to any communication system with similar problems, such as wireless local area network (Wireless Local Area Network, WLAN), wired communication system, or other communication systems developed in the future, etc.

The term "terminal device" used in this disclosure refers to any terminal device capable of wired or wireless communication with network devices or with each other. The terminal equipment may sometimes be called user equipment (User Equipment, UE). A terminal device may be any type of mobile terminal, stationary terminal or portable terminal. As an example, a terminal device may include a mobile phone, a station, a unit, a device, a mobile terminal (Mobile Terminal, MT), a subscription station (Subscriber Station, SS), a portable subscription station (Portable Subscriber Station, PSS), an Internet node, a communicator, Desktop Computers, Laptop Computers, Notebook Computers, Tablet Computers, Personal Communication System (PCS) Devices, Personal Navigation Devices, Personal Digital Assistants (PDA), Positioning Devices, Radio Broadcast Receivers, E-Book Devices, Gaming Devices, Internet of Things (Internet of Things, IoT) devices, vehicle-mounted devices, aircraft, virtual reality (Virtual Reality, VR) devices, augmented reality (Augmented Reality, AR) devices, wearable devices, terminal devices in 5G networks or public land for future evolution Any terminal device in the mobile network (Public Land Mobile Network, PLMN), other devices that can be used for communication, or any combination of the above. Embodiments of the present disclosure do not limit this.

The term "network device" as used in this disclosure is an entity or node that can be used to communicate with end devices. The network device may be, for example, a radio access network (Radio Access Network, RAN) network device. Network equipment may include various types of base stations. As an example, the network device may include various forms of macro base stations, micro base stations, pico base stations, femto base stations, relay stations, access points, remote radio units (Remote Radio Unit, RRU), radio heads (Radio Head, RH), Remote Radio Head (Remote Radio Head, RRH) and so on. In systems using different radio access technologies, the names of network equipment may be different, for example, it is called an evolved Node B (eNB or eNodeB) in an LTE network, and it is called a Node B (NodeB) in a 3G network , which may be called g-Node B (gNB) or NR Node B (NR NB) in 5G networks, and so on. Embodiments of the present disclosure do not limit this.

The term "relay terminal device" used herein refers to a terminal device capable of providing a relay service between a network device and a terminal device. The term "remote terminal device" used herein refers to a terminal that supports access to a network device through a relay service.

The term "Radio Bearer (RB)" used in this article refers to the general term for a series of protocol entities and configurations allocated by the base station to the UE. Services for transmitting user data between, including packet data convergence protocol (Packet Data Convergence Protocol, PDCP) protocol entity, radio link control (Radio Link Control, RLC) protocol entity, medium access control (Medium Access Control, MAC) protocol entity And a series of resources allocated by Physical (PHY), etc. Radio bearers are divided into data radio bearers and signaling radio bearers. The term "layer 2" used here is a general term for sublayers of MAC/RLC/PDCP/Service Data Adaptation Protocol (Service Data Adaptation Protocol, SDAP). In a sidelink communication scenario, it is called a sidelink radio bearer. The term "radio link control layer radio bearer" used in this document refers to protocol entities and configurations below the RLC layer, including RLC protocol entities, MAC protocol entities, and a series of resources allocated by the PHY.

As mentioned above, sidelink communications have been proposed. It is significantly different from the traditional cellular communication network architecture. In the traditional cellular network communication architecture, a terminal device needs to pass through a base station to communicate with another terminal device. In D2D communication, terminal devices can communicate through sidelink links. As shown in Figure 1, the communication between the terminal device 110-1 and the terminal device 110-2 needs to be realized through the network device 120, and the terminal device 110-1 can directly communicate with the terminal device 110-3 through the side link . Based on the U2N relay communication technology, the terminal device 110-1 can assist the terminal device 110-3 to transfer data.

There are two existing U2N relay communication methods: L2 U2N relay communication and L2 U2N relay communication. In L2 U2N relay communication, the data packets of the remote terminal device are relayed and forwarded below the PDCP layer of the relay terminal device, that is, the relay terminal device only maintains the RLC bearer of the relay, including the RLC, MAC and PHY layers. In addition, the protocol architecture adds an adaptation layer (Adaptation Layer) between the RLC layer and the PDCP layer. The main role of the adaptation layer is to multiplex and split bearers, that is, to support multiplexing of different bearers to one bearer or to split one bearer into different bearers.

The following behavior is an example. When the relay terminal equipment receives the data packet to be forwarded from the base station, the data packet will have an adaptation layer header (Header), which will contain the end-to-end bearer identifier (End-to-End Data) to which the data belongs. Radio Bearer Identity, E2E DRB ID). In the L2 U2N relay architecture, the end-to-end bearer identifier is associated with the PDCP entity and the SDAP entity. The relay terminal device forwards the data packet to the corresponding PC5 RLC bearer by identifying the information in the header of the adaptation layer and the configured mapping relationship (that is, the mapping between the end-to-end bearer identifier and the PC5 RLC bearer). A bearer of the Uu link between the terminal device and the network device may also contain data sent by the base station to multiple remote terminal devices. The adaptation layer of the terminal device will correctly map the data on the bearer of the Uu link to the bearer of different remote terminal devices according to the identification of the remote terminal device, so as to realize the splitting of the multiplexed data.

When a terminal device moves, the network equipment serving the terminal device may change. The mobility management of the terminal equipment is to change the serving cell of the terminal equipment so that no matter how the terminal equipment moves within the network coverage area, it can enjoy uninterrupted services. In a radio resource control (Radio Resource Control, RRC) connected state, a terminal device obtains continuous services from the network through cell handover (Handover, HO) during the moving process.

For the cell handover of the relay terminal equipment, how to switch the remote terminal equipment connected to the relay terminal is an urgent problem to be solved. A way of group handover has been proposed to solve the problem of how the remote terminal equipment performs handover. Specifically, when a cell handover occurs on the relay terminal device, the remote terminal device will switch to the target cell together with the relay terminal device. During the whole process, the sidelink connection between the remote terminal device and the relay terminal device will not be disconnected. However, in the latest meeting, it has been clearly stated that the switching method of group switching is not supported.

Further, according to some technical solutions, after the relay terminal device receives the handover command message sent by the source network device, the relay terminal device directly releases the sidelink connection with the remote terminal device. According to other technical solutions, before the source network device sends a switching command to the relay terminal device, it sends a switching command to the remote terminal device to switch to other relay terminal devices or cells.

However, the problem of data loss may occur in all the above-mentioned relay terminal device mobility management solutions. Specifically, taking the uplink transmission as an example, the remote terminal device sends RLC service data units (Service DataUnit, SDU) #1-4 to the relay terminal device, and receives the RLC SDU#1, #2 fed back by the relay terminal device , and the acknowledgment (Acknowledgment, ACK) of #4 and the negative acknowledgment (Negative Acknowledgment, NACK) of RLC SDU#3. On the uplink between the relay terminal device and the source network device, the relay terminal device sent RLC SDU #1 and #2 to the source network device, and received the RLC SDU #1 and #2 fed back by the source network device NACK. Immediately afterwards, the relay terminal device receives a handover command from the source network device, and the relay terminal device directly disconnects the sidelink connection and switches to the target network device.

After the remote terminal device and the relay terminal device are disconnected from the sidelink link, they will automatically reselect the cell or the relay terminal device, and connect to the destination base station selected by the remote terminal device through the re-establishment process. After the re-establishment of the remote terminal device is completed, the remote terminal device will start to transmit to the destination base station of the remote terminal device sequentially from the first data packet that has not received the ACK, that is, RLC SDU#3. After the relay terminal device is switched, the RLC is re-established, and all RLC SDU data in the sending buffer will be discarded. If the remote terminal device does not save the PDCP PDU after receiving the RLC ACK of the relay terminal device, then after the remote terminal device connects to a new base station, it will not be able to request the remote terminal device to restart Upload RLC SDU#1 and #2, therefore, the RLC SDU#1 and #2 of the remote terminal equipment will be lost.

Similarly, in the downlink transmission direction, after the source network device sends the RLC SDU, although it receives the ACK fed back by the relay terminal device, if a cell handover occurs before the relay terminal device forwards the data to the remote terminal device , and the corresponding data received in the ACK is no longer saved in the PDCP, the data loss problem will also occur.

In addition, in the U2N relay communication scenario, when the remote device performs cell handover, according to the method in the prior art, the remote terminal device reports to the base station the relay terminal devices available in the surrounding area by measuring and reporting. If the system has a terminal device ( UE) can only perform cell handover with the same base station, and the relay terminal equipment reported by the remote terminal equipment does not belong to the base station where the remote terminal equipment is located, then the source network equipment will make a decision of handover failure. In addition, from another perspective, this measurement report will generate unnecessary overhead.

To solve the above problems and other potential problems, in the embodiment of the present disclosure, the relay terminal device relays the communication between the remote terminal device and the source network device. The relay terminal device receives an instruction to switch to the target network device from the source network device. After the relay terminal device switches to the target network device, the relay device sends the data buffered at the relay terminal device to the remote terminal device and/or the target network device. A user plane tunnel is established between the source network device and the target network device, and the data associated with the remote terminal device received by the target network device from the relay terminal device is received. In this way, the data loss of the relay terminal device during the handover process is avoided.

FIG. 2 shows a schematic diagram of a communications environment 200 in which embodiments of the present disclosure may be implemented. The communication environment 200 includes terminal equipment 210-1, terminal equipment 210-2, terminal equipment 210-3, terminal equipment 210-4, ..., terminal equipment 210-N, which may be collectively referred to as "terminal equipment 210" , where N is any positive integer. The communication environment 200 as a part of the communication network also includes a network device 220-1, a network device 220-2, a network device 220-3, ..., a network device 220-M, which may be collectively referred to as "network device 220 ”, where M is any positive integer. The terminal device 210 and the network device 220 can communicate with each other. Terminal device 210 may also receive messages from core network devices. The term "entity" used herein refers to a network element that can implement a specific function.

As shown in FIG. 2 , the terminal device 210-1 communicates with the network device 220-1 (that is, through a Uu link), and the terminal device 210-1 can communicate with the terminal device 210-2 via a side link. As the terminal device 210-1 moves, the terminal device 210-1 may switch to the network device 220-2. The terminal device 210-2 can access the network device 220-1 via the terminal device 210-1. In this case, terminal device 210-1 is a relay terminal device that relays communication between network device 220-1 and terminal device 210-2, and terminal device 210-2 accesses A remote terminal device of the network device 220-1. It should be understood that there may be more than one terminal device that can access the network device 220-1 through the terminal device 210-1. That is to say, one relay terminal device may have multiple remote terminal devices ready. For the purpose of illustration only, in the following description of the present disclosure, the terminal device 210-1 refers to the relay terminal device, the terminal device 210-2 refers to the remote terminal device, and the network device 220-1 refers to the source network device and the network Device 220-2 refers to a target network device. It can be understood that, according to different connection modes, the relay terminal device and the remote terminal device may be any suitable device in the terminal device 210 , and the source network device and the target network device may be any suitable device in the network device 220 . The relay terminal device may be located within the coverage area of the cell. The remote terminal equipment may be located within the coverage area of the cell, or may move out of the coverage area of the cell.

The term "uplink (UL) data" used herein refers to data sent by a remote terminal device to a network device via a relay terminal device. The term "downlink (Downlink, DL) data" used herein refers to data sent by a network device to a remote terminal device via a relay terminal device.

Communications environment 200 may include any suitable number of devices and cells. In the communication environment 200, the terminal device 210 and the network device 220 can communicate data and control information with each other. It should be understood that the number of various devices and their connections shown in FIG. 2 are given for illustrative purposes and no limitation is suggested. Communications environment 200 may include any suitable number of devices and networks suitable for implementing embodiments of the present disclosure.

Communications in the communication environment 200 may be implemented according to any suitable communication protocol, including but not limited to first generation cellular communication protocol (1G), second generation cellular communication protocol (2G), third generation cellular communication protocol (3G), WLAN communication protocols such as fourth-generation cellular communication protocols (4G) and fifth-generation cellular communication protocols (5G), such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, etc., and/or any other currently known or will develop in the future. In addition, communication may utilize any suitable wireless communication technology, including but not limited to: code division multiple access (Code Division Multiple Access, CDMA), frequency division multiple access (Frequency Division Multiple Access, FDMA), time division multiple access (Time Division Multiple Access, TDMA), frequency division duplex (Frequency Division Duplex, FDD), time division duplex (Time Division Duplex, TDD), multiple input multiple output (Multi-Input Multi-Output, MIMO), orthogonal frequency division multiplexing (Orthogonal Frequency Division Multiplexing OFDM), Discrete Fourier Transform-spread-OFDM (Discrete Fourier Transform-spread-OFDM, DFT-s-OFDM), and/or any other technology currently known or to be developed in the future.

Exemplary embodiments of the present disclosure will be discussed in detail below with reference to the accompanying drawings. When describing the signaling interaction process in FIG. 3 to FIG. 9 below, for ease of discussion, the signaling interaction between communication entities according to an exemplary embodiment of the present disclosure will be described with reference to the exemplary communication environment in FIG. 2 . It should be understood that example embodiments of the present disclosure may be similarly applied in other communication environments.

According to some embodiments of the present disclosure, after transmitting all DL data to the remote terminal device, the relay terminal device releases the sidelink with the remote terminal device. The relay terminal device also forwards the UL data in the cache to the source network device through the target network device, thereby avoiding data loss during the switching process of the relay terminal device. For example, FIG. 3 shows an interactive signaling diagram of a specific communication process 300 according to the above solution. As shown in FIG. 3, the communication process 300 involves the terminal device 210-1, the terminal device 210-2, the network device 220-1, and the network device 220-2. It can be understood that the communication process shown in FIG. 3 is only exemplary rather than limiting. Embodiments of the present disclosure may include interactive signaling not shown in FIG. 3 , or omit some signaling shown in FIG. 3 .

The network device 220-1 and the terminal device 210-2 communicate 3005 through the terminal device 210-1. For example, the network device 220-1 sends the DL data for the terminal device 210-2 to the terminal device 210-1, and the terminal device 210-1 then sends the DL data to the terminal device 210-2. The terminal device 210-2 sends UL data to the terminal device 210-1, and the terminal device 210-1 sends the UL data to the network device 220-1.

Perform 3010 measurement configuration and measurement reporting between the network device 220-1 and the terminal device 210-1. The network device 220-1 may send the measurement configuration to the terminal device 210-1. The measurement configuration can be sent through an RRC message. For example, a measurement configuration may include the type of measurement quantity. As an example only, the type of the measurement quantity may be one or a combination of more of the following: Reference Signal Received Power (Reference Signal Received Power, RSRP), Reference Signal Received Quality (Reference Signal Received Quality, RSRQ). The measurement configuration may also include one or more of the following: a list of cells to be measured, a report configuration, a measurement identifier, and event parameters. The reporting configuration may include reporting criteria that trigger the end device to send a measurement report. This can be periodic or a description of a single event. The reporting configuration may also include a reporting format, which indicates the quantities and related information (eg, the number of reporting cells) to be included by the terminal device in the measurement report. Each measurement ID corresponds to a measurement object and a report configuration. It can be understood that the measurement configuration may include any suitable parameters for handover related measurements. The terminal device 210-1 reports the measurement result. In some embodiments, the measurement results correspond to a measurement type indicated in the configuration information. In some embodiments, if the measurement configuration includes a reporting period, the terminal device 210-1 may report based on the indicated period. Alternatively, the terminal device 210-1 may be triggered to report the measurement result.

The network device 220-1 determines 3015 that the terminal device 210-1 is to be handed over to the network device 220-2 according to the measurement report. For example, if the reported measurement result indicates that the RSRP of the network device 220-2 exceeds a predetermined threshold, the network device 220-1 determines that the terminal device 210-1 needs to switch to the network device 220-2. In other embodiments, if the reported measurement result indicates that the RSRP of the network device 220-2 exceeds the RSRP of the network device 220-1, the network device 220-1 determines that the terminal device 210-1 will switch to the network device 220-2. It can be understood that the network device 220-1 may determine that the terminal device 210-1 is to be handed over to the network device 220-2 according to any suitable parameter in the reported measurement result. Embodiments of the present disclosure are not limited in this respect.

The network device 220-1 sends 3020 a handover request to the network device 220-2 to request handover of the terminal device 210-1 to the network device 220-2. In some embodiments, the handover request may include a mapping relationship between the remote terminal device (ie, terminal device 210-2) identifier and the peer-to-peer data radio bearer identifier. For example, the remote terminal device identifier (ID) may be a temporary identifier allocated by the terminal device 210-1 or the network device 220-1. Alternatively, the identifier of the remote terminal device may be a radio network temporary identity (Radio Network Temporary Identity, RNTI) of the remote terminal device. It should be understood that the identifier of the remote terminal device may also include other appropriate identifiers, which will not be described in detail here. In some embodiments, a remote terminal device may include multiple radio bearers, so the above mapping relationship may be a one-to-many mapping, that is, an identifier of a remote terminal device corresponds to a plurality of end-to-end data radio bearer identifiers . For example, the above mapping relationship may indicate the identity of the terminal device 210-2 and the identifiers of multiple peer-to-peer data radio bearers associated with the terminal device 210-2.

After the network device 220-2 performs the admission control, the network device 220-2 sends 3025 an acknowledgment message of the handover request to the network device 220-1. The confirmation message may include relevant configurations required for the terminal device 210-1 to access the network device 220-2. For example, the confirmation message may include the bearer configuration between the terminal device 210-1 and the network device 220-2. In some embodiments, the confirmation message may further include an RLC bearer configuration for transmitting the relay data buffered by the terminal device 210-2 in the terminal device 210-1.

The network device 220-2 knows the end-to-end data radio bearer identifier of each remote terminal device, and performs bearer configuration for the data of each end-to-end data radio bearer identifier, so as to be used in the UL data transmission of the remote terminal device. Relay transmission, this configuration is used to establish an RLC bearer between the relay terminal device and the network device 220-2. In some embodiments, if the network device 220-2 does not perform RLC bearer multiplexing during configuration, the network device 220-2 configures a dedicated RLC bearer for the end-to-end data radio bearer identifier of each remote terminal device. In this case, the network device 220-2 sends to the network device 220-1 in the form of multiple sets of {remote terminal device identifier, peer-to-peer data radio bearer identifier, RLC bearer configuration parameters}. Alternatively, if network device 220-2 performs RLC bearer multiplexing during configuration, that is, multiple radio bearers share the same RLC bearer, then network device 220-2 uses {{remote terminal device identifier 1, end-to-end data radio Bearer identifier 1}, ..., {remote terminal equipment identifier x, end-to-end data radio bearer identifier x}, RLC configuration parameters} to send to network device 220-1, wherein if multiple radio bearer, the above remote terminal device identifiers 1 to x are the same identifier. In other embodiments, if multiple radio bearers of the same remote terminal device share the same RLC bearer, the network device 220-2 uses {{remote terminal device ID 1, peer-to-peer data radio bearer ID 1, ... , end-to-end data radio bearer identifier x}, RLC configuration parameters} and send to the network device 220-1.

A user plane tunnel is established 3030 between the network device 220-1 and the network device 220-2, for the network device 220-2 to forward data related to the terminal device 210-2 to the network device 220-1. In some embodiments, the establishment of the user plane tunnel may be initiated by the network device 220-1. In other embodiments, the establishment of the face tunnel may be initiated by the network device 220-2. In some embodiments, the network device 220-1 can configure and establish a user plane tunnel. The radio bearers of all remote terminal devices can reuse the user plane tunnel. In other embodiments, the network device 220-1 may establish and configure a user plane tunnel for each remote terminal device. In this manner, the network device 220-1 further configures a mapping relationship between a tunnel endpoint identifier (TunnelEndpoint Identifier, TEID)/transport network layer (Transport Network Layer, TNL) address and a remote terminal device identifier. In some other embodiments, the network device 220-1 may separately establish and configure a user plane tunnel for the end-to-end data radio bearer identifier of each remote terminal device. In this case, the network device 220-1 further configures the mapping relationship between the TEID/TNL address and each group of {remote terminal device identifier, radio bearer identifier}.

The network device 220-1 sends 3035 the first indication to the terminal device 210-1. The first instruction is used to instruct the terminal device 210-1 to switch from the network device 220-1 to the network device 220-2. The first indication may be an RRC reconfiguration message. After receiving the first indication, the terminal device 210-1 will simultaneously perform DL data transmission and switching. For example, terminal device 210-1 switches 3040 to network device 220-2. End device 210-1 leaves network device 220-1 and switches 3040 to network device 220-2. The terminal device 210-1 completes the connection with the network device 220-2 according to the RRC configuration.

After receiving the first indication, the terminal device 210-1 sends 3045 an abort indication to the terminal device 210-2. The suspension indication is used to instruct terminal device 210-2 to stop sending UL data to terminal device 210-1. Terminal device 210-1 maintains a sidelink connection with terminal device 210-2, and sends 3050 DL data to terminal device 210-2. After sending all the DL data, the terminal device 210-1 releases 3055 the sidelink with the terminal device 210-2. The DL data is data received by the terminal device 210-1 and not sent to the terminal device 210-2 before the handover is performed.

The terminal device 210-1 sends 3060 the UL data to the network device 220-2 through the configured RLC bearer. The UL data is data received by the terminal device 210-1 and not sent to the network device 220-1 before the handover is performed. The UL data may include RLC SDUs and adaptation layer headers. In some embodiments, RLC bearers are not multiplexed. Alternatively, RLC bearers can be multiplexed. For example, RLC bearers may be multiplexed among all remote terminal devices, or RLC bearers may be multiplexed between radio bearers of one remote terminal device. If the RLC bearer is not multiplexed, the terminal device 210-1 does not need to add additional information. The terminal device 210-1 only needs to submit the E2E DRB data of different remote terminal devices to the RLC bearer according to the configuration. If the RLC bearer is multiplexed between all remote terminal devices, the terminal device 210-1 adds the identifier of the terminal device 210-2 and the corresponding radio bearer identifier in the header of the adaptation layer. In other embodiments, if the RLC bearer is multiplexed between the radio bearers of a remote terminal device, the terminal device 210-1 adds a corresponding radio bearer identifier to the header of the adaptation layer.

The network device 220-2 sends 3065 UL data to the network device 220-1 through the user plane tunnel. According to different user plane tunnel multiplexing methods, the network device 220-2 will use different methods to distinguish E2E DRB data of different remote terminal devices. If a distinction has been made in the configuration of the user plane tunnel, there is no need to add corresponding identification information to the data packet header. If there is no distinction on the bearer, that is, the bearer is multiplexed, it is necessary to add identification information to the header for data identification and correct delivery. Table 1 shows the processing of data by the network device 220-2 based on different RLC configurations and tunnel configurations.

Table 1

After the network device 220-1 receives the UL data forwarded over the tunnel, the network device 220-1 can, according to the information in the header of the adaptation layer packet or the mapping relationship between the tunnel and the DRB IDs of different remote terminal devices, Correctly submit the RLC SDU data to the upper layer, namely Uu PDCP.

After the terminal device 210-1 completes the transmission of the UL data, the terminal device 210-1 sends 3070 a transmission completion indication to the network device 220-2, so as to indicate the completion of the transmission of the UL data. The transmission completion indication can also be used to instruct the network device 220-2 to perform RRC reconfiguration on the terminal device 210-1, to instruct to release the bearer used for the remote terminal device to relay data, and to release the network device 220-2 and the network device Tunnel between 220-1. In some embodiments, the transmission completion indication may be carried directly on the data. Carrying directly on the data means carrying indication information on the last data packet sent by the terminal device 210-1, indicating that this is the last data packet. As shown in FIG. 4A , the last piece of data includes a header part 411 and a payload part 413 . A transfer complete indication 412 may be added to the packet header portion 411 . In some embodiments, a sequence number (Sequence Number, SN) value of the data packet may be used to indicate that this is the last UL data packet in the cache of the terminal device 210-1. For example, the SN value of the last data packet can be set to all 0s or all 1s.

Alternatively, the transfer completion indication may be sent separately. If the transmission completion indication is sent separately from the data packet, the terminal device 210-1 may send the transmission completion indication after receiving the ACK of the last data packet from the network device 220-2. In this case, the transmission completion indication may be in the form of a data packet including a PDCP PDU and an adaptation layer, that is, an adaptation layer PDU. The data packet is generated by the adaptation layer of the terminal device 210-1, the adaptation layer is added with indication information that the data transmission is completed, and the data part is empty. As shown in FIG. 4B , the transmission completion indication may include a header part 421 and a data part 423 . The data section 423 may be empty. In other embodiments, the RRC layer of the terminal device 210-1 generates a dedicated RRC message, and sends the transmission completion indication through RRC signaling. In some other embodiments, the transmission completion indication may be carried in a MAC control element (Control Element, CE), or carried in dedicated physical layer signaling.

The network device 220-2 sends 3075 an indication that the transmission is complete to the network device 220-1, instructing the network device 220-1 to release the connection with the core network. The terminal device 210-2 reselects 3080 a cell or a relay terminal device. After the terminal device 210-2 selects a new cell or a relay terminal device, it re-accesses the network through a re-establishment process. It can be understood that the terminal device 210-2 may reselect 3080 a cell or a relay terminal device at any time after the transmission of the suspension indication (3045). In other words, the reselection 3080 can occur before the sending step (3050) or can occur simultaneously with the sending step (3050). Reselecting 3080 may occur after the sending step (3050). Similarly, reselection 3080 may occur before or after or simultaneously with sending steps 3055, 3060, 3065, 3070, and 3075.

According to the above embodiments, it is ensured that the uplink and downlink data packets of the remote terminal device will not be lost during the switching process of the relay terminal device. When the relay terminal device receives the handover request, this embodiment does not directly release the sidelink connection between the relay terminal device and the remote terminal device, but continues to transmit downlink data until the buffer is cleared. At the same time, a communication link between the relay terminal device and the target base station and between the target base station and the source base station is established to relay the UL data of the remote terminal device buffered in the relay terminal device.

According to other embodiments of the present disclosure, the relay terminal device switches to the target network device after receiving the switching instruction. The relay terminal device forwards the UL and DL data associated with the remote terminal device cached in the relay terminal device to the source network device through the target network device, thereby avoiding data loss during the switching process of the relay terminal device . For example, FIG. 5 shows an interactive signaling diagram of a specific communication process 500 according to the above solution. As shown in FIG. 5, the communication process 500 involves the terminal device 210-1, the terminal device 210-2, the network device 220-1, and the network device 220-2. It can be understood that the communication process shown in FIG. 3 is only exemplary rather than limiting. Embodiments of the present disclosure may include interactive signaling not shown in FIG. 5 , or omit some signaling shown in FIG. 5 .

The network device 220-1 and the terminal device 210-2 communicate 5005 through the terminal device 210-1. The network device 220-1 and the terminal device 210-1 perform 5010 measurement configuration and measurement reporting. The network device 220-1 determines 5015 that the terminal device 210-1 is to be handed over to the network device 220-2 according to the measurement report. The network device 220-1 sends 5020 a switching request to the network device 220-2, to request switching the terminal device 210-1 to the network device 220-2. After the network device 220-2 performs the admission control, the network device 220-2 sends 5025 an acknowledgment message of the handover request to the network device 220-1. The above steps 5005, 5010, 5015, 5020, and 5025 are the same as steps 3005, 3010, 3015, 3020, and 3025 described with reference to FIG.

A user plane tunnel is established 5030 between the network device 220-1 and the network device 220-2, so that the network device 220-2 forwards data related to the terminal device 210-2 to the network device 220-1. In some embodiments, the network device 220-1 may establish and configure a user plane tunnel for UL and DL data of the remote terminal device. In other embodiments, the network device 220-1 may establish and configure two user plane tunnels, which are respectively used for UL and DL data of the remote terminal device. In other embodiments, the network device 220-1 may separately establish and configure a user plane tunnel for the UL and DL data of each remote terminal device, and configure the mapping relationship between the TEID/TNL address and the remote terminal device ID. Alternatively, the network device 220-1 may separately establish and configure a user plane tunnel for each remote terminal device's E2E DRB (including a DL-oriented DRB and a UL-oriented DRB), and configure a TEID/TNL address and each group { The mapping relationship between remote terminal device ID and DRB ID}. In some embodiments, the network device 220-1 can establish and configure user plane tunnels for multiple E2E DRBs of one or more remote terminal devices (that is, regardless of uplink DRB or downlink DRB), and configure TEID/TNL The mapping relationship between the address and each group {remote terminal device ID, DRB ID, UL/DL identifier}.

Generally speaking, network device 220-1 can configure the TEID/TNL address and {remote terminal device ID, DRB ID, UL/DL identifier} according to the corresponding relationship between the bearer of the remote terminal device and the user plane tunnel. A mapping relationship between one or more identifiers.

The network device 220-1 sends 5035 the first indication to the terminal device 210-1. The first instruction is used to instruct the terminal device 210-1 to switch from the network device 220-1 to the network device 220-2. Terminal device 210-1 switches 5040 to network device 220-2. The above steps 5035 and 5040 are the same as the steps 3035 and 3040 described with reference to FIG. 3 , so details are not repeated here.

After receiving the first indication, terminal device 210-1 releases 5045 the sidelink with terminal device 210-2. The release 5045 may occur concurrently with the switching 5040, or after the switching 5040. The terminal device 210-2 reselects 5050 a cell or a relay terminal device. After the terminal device 210-2 selects a new cell or a relay terminal device, it re-accesses the network through a re-establishment process.

End device 210-1 sends data associated with end device 210-2 to network device 220-2. For example, terminal device 210-1 sends 5055 DL data to network device 220-2. The DL data is data received by the terminal device 210-1 and not sent to the terminal device 210-2 before the handover is performed. The terminal device 210-1 also sends 5060 UL data to the network device 220-2. The UL data is data received by the terminal device 210-1 and not sent to the network device 220-1 before the handover is performed. In some embodiments, different radio bearers for UL data and DL data may be established between the terminal device 210-1 and the network device 220-2 for data transmission. Alternatively, the terminal device 210-1 and the network device 220-2 may establish the same radio bearer for UL data and DL data for data transmission, and the network device 220-2 may add indication information in the data packet header to indicate the Whether the data is UL data or DL data.

In some embodiments, if the RLC bearer is not multiplexed, the network device 220-2 configures a dedicated RLC bearer for the E2E DRB of each remote terminal device. If the RLC bearer is multiplexed, that is, multiple DRBs share the same RLC bearer. At this point, the terminal device 210-1 will establish uplink and downlink data bearers, one bearer is used to transmit/multiplex all UL data, and one bearer is used to transmit/multiplex all DL data. If the RLC bearer is not multiplexed, the terminal device 210-1 does not need to add additional information. The terminal device 210-1 only needs to submit the E2E DRB data of different remote terminal devices to the RLC bearer according to the configuration. In other embodiments, if the RLC bearer is multiplexed among all remote terminal devices, the terminal device 210-1 adds the identifier of the terminal device 210-2 and the corresponding radio bearer identifier in the header of the adaptation layer. In other embodiments, if the RLC bearer is multiplexed between the radio bearers of a remote terminal device, the terminal device 210-1 adds a corresponding radio bearer identifier to the header of the adaptation layer.

Optionally, before the data is forwarded, the network device 220-1 may send a DL data transmission report to the terminal device 210-1 through the network device 220-2, which is used to tell the terminal device 210-1 which remote terminal devices' downlink data is still available. In the cache of the network device 220-1, uploading of repeated data is reduced.

The network device 220-2 sends 5065 UL data and DL data to the network device 220-1 through the user plane tunnel. According to different multiplexing methods, the network device 220-2 will use different methods to distinguish the E2E DRB data of different remote terminal devices. If the bearer configuration has been differentiated, there is no need to add corresponding identification information to the data packet header. If there is no distinction on the bearer, that is, the bearer is multiplexed, it is necessary to add identification information to the header for data identification and correct delivery. The sending 5065 of UL data and DL data may be similar to the sending 3065 of UL data in FIG. 3 , which will not be repeated here. After the network device 220-1 receives the UL data and DL data forwarded over the tunnel, the network device 220-1 can use the information in the header of the adaptation layer or the mapping between the tunnel and the DRB ID of different remote terminal devices relationship, and correctly submit the RLC SDU data to the upper layer, that is, Uu PDCP.

After the terminal device 210-1 completes the transmission of the UL data and the DL data, the terminal device 210-1 sends 5070 a transmission completion indication to the network device 220-2, so as to indicate the completion of the transmission of the UL data. The transmission completion indication can also be used to instruct the network device 220-2 to perform RRC reconfiguration on the terminal device 210-1, to instruct the release of the data relay bearer for the remote terminal device, and to release the network device 220-2 and the network device 220-1 between tunnels. The sending manner of the transmission completion indication is similar to the sending 3070 of the transmission completion indication described with reference to FIG. 3 , and will not be repeated here. The network device 220-2 sends 5075 an indication that the transmission is complete to the network device 220-1, instructing the network device 220-1 to release the connection with the core network.

According to the above embodiments, by establishing a bearer or communication path between the relay terminal device and the target network device, and between the target network device and the source network device, the relay terminal device transmits the cached UL data and DL data of the remote terminal device through the target The network device relays and forwards to the source network device, ensuring that the uplink and downlink data packets of the remote terminal device will not be lost during the switching process of the relay terminal device. When the relay terminal device receives the handover request, the relay terminal device directly releases the sidelink connection with the remote terminal device, but different from the existing technology, the relay terminal device will establish the relay terminal device and the target network The bearer of the device uploads the cached uplink and downlink data of the remote terminal device to the target network device, and then the target network device forwards it to the source network device.

According to still some embodiments of the present disclosure, after the relay terminal device receives the handover request from the source network device, the relay terminal device maintains the sidelink link with the remote terminal device, and transfers the UL and The DL data is forwarded to the remote terminal equipment through the side link. For example, FIG. 6 shows an interactive signaling diagram of a specific communication process 600 according to the above solution. As shown in FIG. 6, the communication process 600 involves the terminal device 210-1, the terminal device 210-2, the network device 220-1, and the network device 220-2. It can be understood that the communication process shown in FIG. 6 is only exemplary and not restrictive. Embodiments of the present disclosure may include interactive signaling not shown in FIG. 6 , or omit some signaling shown in FIG. 6 .

The network device 220-1 and the terminal device 210-2 communicate 6005 through the terminal device 210-1. The network device 220-1 and the terminal device 210-1 perform 6010 measurement configuration and measurement reporting. The network device 220-1 determines 5015 that the terminal device 210-1 is to be handed over to the network device 220-2 according to the measurement report. The network device 220-1 sends 6020 a switching request to the network device 220-2, to request switching the terminal device 210-1 to the network device 220-2.

After the network device 220-2 performs admission control, the network device 220-2 sends 6025 a handover request confirmation message to the network device 220-1. The acknowledgment message of the handover request carries relevant configurations required for the terminal device 210-2 to access the network device 220-2. Since the remote terminal devices below the terminal device 210-2 will perform cell/relay terminal device reselection, this configuration no longer includes the configuration for data relay of the remote terminal devices.

The network device 220-1 sends 6030 the first indication to the terminal device 210-1. The first instruction is used to instruct the terminal device 210-1 to switch from the network device 220-1 to the network device 220-2. Terminal device 210-1 switches 6035 to network device 220-2. After receiving the first indication, the terminal device 210-1 sends 6045 an abort indication to the terminal device 210-2. The suspension indication is used to instruct terminal device 210-2 to stop sending UL data to terminal device 210-1. The above steps 6030, 6035 and 6045 are the same as the steps 3035, 3040 and 3045 described with reference to FIG. 3 , so details are not repeated here.

The terminal device 210-1 maintains a sidelink with the terminal device 210-2, and transmits 6050 the DL data buffered at the terminal device 210-1 to the terminal device 210-2 through the sidelink. The DL data is data received by the terminal device 210-1 and not sent to the terminal device 210-2 before the handover is performed. In some embodiments, terminal device 210-1 and terminal device 210-2 establish 6055 a unicast connection. The unicast connection may be used to send UL data buffered at the terminal device 210-1. In some embodiments, the terminal device 210-1 can add a bearer to the original side link for data transmission, and can also establish a new unicast connection and configure a bearer (side link) for E2E DRB data of different remote terminal devices. Link DRB). Terminal device 210-1 sends 6060 UL data to terminal device 210-2. The UL data is data received by the terminal device 210-1 and not sent to the network device 220-1 before the handover is performed. In some embodiments, the terminal device 210-1 may send UL data on the newly established unicast connection. Alternatively, terminal device 210-1 may send UL data on the original sidelink. It will be appreciated that the sending 6050 of DL data may occur before or after the establishment 6055 of the unicast connection. Transmission 6050 of DL data may also occur before or after transmission 6060 of UL data.

After the terminal device 210-1 sends all the data of the remote terminal device in the cache, the terminal device 210-1 releases 6065 the sidelink connection between the terminal device 210-2. After receiving (6045) the suspension indication, the terminal device 210-2 reselects 6070 a cell or a relay terminal device. After the terminal device 210-2 selects a new cell or a relay terminal device, it re-accesses the network through a re-establishment process. That is to say, there is no sequence between reselecting 6070 a cell or a relay terminal device and steps 6050, 6055, 6060 and 6065.

According to the above embodiments, when the relay terminal device switches, the relay terminal device sends the UL and DL data of the remote terminal device in the cache to the lost. Different from the existing technology, when the relay terminal device receives the handover request, it will maintain the sidelink connection with the remote terminal device, and may also create a necessary sidelink connection at the same time, and through the sidelink The road sends the UL and DL data of the remote terminal device in the cache to the remote terminal device.

According to some other embodiments of the present disclosure, the source network device determines in advance that the relay terminal device may be handed over, and instructs the remote terminal device of the relay terminal device to reselect the cell and/or the relay terminal device in advance, or forwards the The remote terminal device below the relay terminal device is switched to a new communication path, so as to reduce the UL and/or DL data of the remote terminal device cached when the relay terminal device is switched. For example, FIG. 7 shows an interactive signaling diagram of a specific communication process 700 according to the above solution. As shown in FIG. 7, the communication process 700 involves the terminal device 210-1, the terminal device 210-2, the network device 220-1, and the network device 220-2. It can be understood that the communication process shown in FIG. 7 is only exemplary rather than limiting. Embodiments of the present disclosure may include interactive signaling not shown in FIG. 7 , or omit some signaling shown in FIG. 7 .

The network device 220-1 and the terminal device 210-2 communicate 7005 through the terminal device 210-1. The network device 220-1 and the terminal device 210-1 perform 7010 measurement configuration and measurement reporting. The above steps 7005 and 7010 are the same as the steps 3005 and 3010 described with reference to FIG. 3 , so details are not repeated here.

The network device 220-1 judges 7015 that the terminal device 210-1 will meet the handover condition based on the reported measurement result. For example, if the reported measurement result indicates that the signal quality of the terminal device 210-1 decreases and gradually approaches the handover threshold, the network device 220-1 may determine that the terminal device 210-1 will perform a handover. Alternatively, if the reported measurement result indicates that the quality of service (Quality of Service, QoS) of the terminal device 210-1 is less than a predetermined threshold, the network device 220-1 may determine that the terminal device 210-1 will perform a handover.

In some embodiments, the network device 220-1 sends 7020 a sixth indication to the terminal device 210-1. The sixth indication is used to indicate that the remote terminal device connected to the terminal device 210-1 can perform cell and/or relay terminal device reselection. Terminal device 210-1 sends 7025 the sixth indication to the remote terminal device (ie, terminal device 210-2).

Alternatively, in some embodiments, after the network device 220-1 pre-judges the handover of the terminal device 210-1, the network device 220-1 may determine 7030 that the terminal device 210-2 needs to perform a handover. In this case, the network device 220-1 sends 7035 a sixth indication (ie a handover indication) to the terminal device 210-1. The sixth indication may include the identity of the target network device of the terminal device 210-2.

Terminal device 210-1 sends 7040 DL data to network device 210-2 via a sidelink. The DL data is data received by the terminal device 210-1 and not sent to the terminal device 210-2 before the handover is performed. When the transmission of all buffered DL data at the terminal device 210-1 is completed, the terminal device 210-1 releases the sidelink connection with the terminal device 210-2. Before the terminal device 210-1 switches to the network device 220-2, the terminal device 210-1 sends 7050 UL data to the network device 220-1. The UL data is data received by the terminal device 210-1 and not sent to the network device 220-1 before the handover is performed. If the DL data buffered at the terminal device 210-1 has been sent before the terminal device 210-1 switches to the network device 220-2, the terminal device 210-1 sends 7055 a transmission completion indication to the network device 220-1. The transmission completion indication may also be used to instruct the network device 220-1 to release the bearer of the relay data of the remote terminal device, that is, perform RRC reconfiguration on the terminal device 210-1. The sending manner of the transmission completion indication is similar to the sending 3070 of the transmission completion indication described with reference to FIG. 3 , and will not be repeated here. Alternatively, if the data buffered at the terminal device 210-1 has not been sent when the terminal device 210-1 transmits the handover, the terminal device 210-1 can transmit these and remote Data associated with end-to-end devices.

According to the above embodiment, it is different from the relay terminal device in the prior art that will disconnect from the remote terminal device only after receiving the switching command, triggering the reselection of the remote terminal device, and the source network device will predict the relay terminal The device may switch and instruct the remote terminal device to reselect the cell/relay terminal device in advance or instruct the remote terminal device to switch in advance, so as to avoid the loss of data packets

According to other embodiments of the present disclosure, after receiving the handover instruction sent by the source network device, the relay terminal device switches to the target network device according to the configuration, while still retaining the sidelink connection and the connection with the source network device. The relay terminal device continues to send the DL data of the remote terminal device in the buffer through the side link connection, and releases the side link after sending; the relay terminal device sends the remote terminal device in the cache through the connection with the source network device UL data, disconnect from the source network device after sending. For example, FIG. 8 shows an interactive signaling diagram of a specific communication process 800 according to the above solution. As shown in FIG. 8, a communication process 800 involves terminal device 210-1, terminal device 210-2, network device 220-1, and network device 220-2. It can be understood that the communication process shown in FIG. 8 is only exemplary rather than limiting. Embodiments of the present disclosure may include interactive signaling not shown in FIG. 8 , or omit some signaling shown in FIG. 8 .

The network device 220-1 communicates 8005 with the terminal device 210-2 through the terminal device 210-1. The network device 220-1 and the terminal device 210-1 perform 8010 measurement configuration and measurement reporting. The network device 220-1 determines 8015 that the terminal device 210-1 is to be handed over to the network device 220-2 according to the measurement report. The network device 220-1 sends 8020 a switching request to the network device 220-2, to request switching the terminal device 210-1 to the network device 220-2. After the network device 220-2 performs the admission control, the network device 220-2 sends 8025 an acknowledgment message of the handover request to the network device 220-1. The network device 220-1 sends 8030 the first indication to the terminal device 210-1. The first instruction is used to instruct the terminal device 210-1 to switch from the network device 220-1 to the network device 220-2. The above steps 8005, 8010, 8015, 8020, 8025 and 8030 are the same as the steps 3005, 3010, 3015, 3020, 3025 and 8035 described with reference to FIG.

Terminal device 210-1 switches 8035 to network device 220-2 while maintaining the connection with network device 220-1. The terminal device 210-1 transmits DL data to the terminal device 210-2 through the sidelink. After the transmission of all DL data is completed, the terminal device 210-1 releases 8045 the sidelink with the terminal device 210-2. After the sidelink is released, the terminal device 210-2 reselects 8050 cell/relay terminal device. The terminal device 210-1 sends 8055 the UL data buffered at the terminal device 210-1 to the network device 210-1. After the transmission of the UL data is completed, the terminal device 210-1 sends 8060 an indication that the transmission is complete to the network device 210-1. The indication of the completion of the transmission may be used to instruct the network device 210-1 to release the connection with the terminal device 210-1. The network device 220-1 releases 8065 the RRC connection between the terminal device 210-1 and the terminal device 210-1.

According to the above embodiments, when the relay terminal device receives the handover request, in the uplink direction, it maintains the side link connection and continues to relay and forward the DL data of the remote terminal device; in the downlink direction, it maintains the connection with the source base station until the relay After forwarding the UL data of the remote terminal equipment.

According to other embodiments, during the relay terminal device discovery process, the remote terminal device indicates whether the relay terminal device is a UE under the same base station through the identification carried in the discovery message, so as to choose whether to include it in the measurement report content. Relay terminal device discovery refers to the process of a UE discovering available relay terminal devices in the surrounding area. There are two main methods: mode A (interaction 900 shown in FIG. 9A ) and mode B (interaction 910 shown in FIG. 9B ). .

As shown in FIG. 9A, in mode A, the terminal device 210-1 broadcasts an announcement (Announcement) message. The message carries information that can be used by surrounding UEs that have discovery rights. The message also includes a Cell Global Identity (CGI). Terminal device 210-1 broadcasts 9005 the message to terminal device 210-2. Terminal device 210-1 also broadcasts 9010 and 9015 the message to terminal device 210-3 and to terminal device 210-4. After receiving the message, the terminal devices 210-2, 210-3, and 230-4 judge whether the terminal device 210-1 is in the same base station as themselves through the carried CGI, and decide accordingly whether to include the terminal device 210-1 in the measurement report. 1.

As shown in FIG. 9B , in mode B, the remote terminal device broadcasts a Solicitation message. The message carries CGI. Terminal device 210-1 broadcasts 9105 the message to terminal device 210-2. Terminal device 210-1 also broadcasts 9110 and 9115 the message to terminal device 210-3 and to terminal device 210-4. After receiving the message, the terminal device reads the CGI information therein. Terminal device 210-2 sends 9120 a response message, and terminal device 210-3 also sends 9130 a response message. The response message carries indication information to inform the terminal device 210-1 whether it is the same base station, for example, Boolean indication information may be used to indicate.

Optionally, the terminal device 210-1 may not carry the CGI in the solicitation message, but the available relay terminal devices in the surroundings may carry CGI information in the response message. At this time, after receiving the response message, the remote terminal device judges whether it is the same base station by reading the CGI information therein.

In other embodiments, the remote terminal device obtains the Physical Cell Identifier (Physical Cell Identifier, PCI) and frequency point information under the current base station, and uses them for judgment. Firstly, the remote terminal equipment needs to obtain the PCI and frequency point information of all the cells of the base station where it is located. In mode A, the peripheral relay terminal equipment carries its own PCI and frequency point information in the broadcast announcement message. After the remote terminal equipment receives it, it compares it with the stored PCI and frequency point information of the base station, thereby judging the Whether the relay terminal device is the same base station. In mode B, the peripheral relay terminal device carries its own PCI and frequency point information when sending a response message, and the remote terminal device compares and judges with the stored PCI and frequency point information after receiving it.

According to the above embodiments, the remote terminal device can determine whether the selected relay terminal device is a UE under the same base station during the discovery process, so that unnecessary measurement reporting can be avoided in the handover scenario between the same base stations.

FIG. 10 shows a flowchart of a method 1000 according to some embodiments of the present disclosure. As an example, the method 1000 may be implemented at a relay terminal device. For example, method 1000 may be implemented at terminal device 210-1. By way of example only, method 1000 is described with reference to FIG. 2 .

At block 1010, the terminal device 210-1 relays communications between the terminal device 210-2 and the network device 220-1.

At block 1020, the terminal device 210-1 receives a first indication from the network device 220-1. The first instruction is used to instruct the terminal device 210-1 to switch from the network device 220-1 to the network device 220-2. In some embodiments, after the terminal device 210-1 receives the first indication, the terminal device 210-1 sends the second indication to the terminal device 210-2. The second instruction is used to instruct the terminal device 210-2 to stop sending data to the network device 220-1.

At block 1030, the terminal device 210-1 performs handover based on the first indication.

At block 1040, the terminal device 210-1 sends the first data from the network device 220-1 to the terminal device 210-2. The first data is the data received by the terminal device 210-1 that has not been successfully sent to the terminal device 210-2 before the handover is performed, or in other words, the first data is received by the terminal device 210-1 from the network device 220-1 received and stored in the cache when the first indication information is received.

In some embodiments, after the terminal device 210-1 sends all the first data, the terminal device 210-1 releases the sidelink with the terminal device 210-2.

In some embodiments, the terminal device 210-1 sends the second data to the terminal device 210-2. The second data comes from the terminal device 210-2. In some embodiments, the terminal device 210-1 sending the second data to the terminal device 210-2 includes:

The terminal device 210-1 sends the second data through the sidelink between the terminal device 210-1 and the terminal device 210-2. . In some embodiments, before the terminal device 210-1 sends the second data, the terminal device 210-1 adds an identifier to the second data. The identifier is used to indicate that the second data comes from the terminal device 210-2. In some embodiments, the terminal device 210-1 establishes a first sidelink bearer. The first sidelink bearer is used for the transmission of the second data. That is to say, the first sidelink bearer is only used to transmit the second data, so that the terminal device 210-2 can know that the data received from the first sidelink bearer is the second data.

FIG. 11 shows a flowchart of a method 1100 according to some embodiments of the present disclosure. As an example, the method 1100 may be implemented at a relay terminal device. For example, method 1100 may be implemented at terminal device 210-1. By way of example only, method 1100 is described with reference to FIG. 2 .

At block 1110, the terminal device 210-1 relays communications between the terminal device 210-2 and the network device 220-1.

In block 1120, the terminal device 210-1 receives a first indication from the network device 220-1, the first indication is used to instruct the terminal device 210-1 to switch from the network device 220-1 to the network device 220-2.

At block 1130, the terminal device 210-1 performs handover based on the first indication.

At block 1140, the terminal device 210-1 sends third data to the network device 220-2, the third data including data received from the remote terminal device before receiving the first indication.

In some embodiments, the third data also includes data from the network device 220-1.

In some embodiments, the terminal device 210-1 establishes one or more radio link control layer bearers based on the bearer configuration in the first indication. In some embodiments, the terminal device 210-1 sends the third data through one or more radio link control layer bearers.

In some embodiments, if it is determined that multiple remote terminal devices multiplex the RLC layer bearer, before the terminal device 210-1 sends the third data, the terminal device 210-1 adds the terminal device 210 to the third data -2 and the bearer identifier of terminal device 210-2. If it is determined that multiple bearers of a remote terminal device multiplex the bearer of the radio link control layer, before the terminal device 210-1 sends the third data, the terminal device 210-1 adds the bearer of the terminal device 210-2 to the third data logo.

In some embodiments, after the terminal device 210-1 sends the third data, the terminal device 210-1 sends the third indication to the network device 220-2. The third indication is used to indicate the completion of the transmission of the third data.

FIG. 12 shows a flowchart of a method 1200 according to some embodiments of the present disclosure. As an example, method 1200 may be implemented at a source network device. For example, method 1200 may be implemented at network device 220-1. By way of example only, method 1200 is described with reference to FIG. 2 .

At block 1210, network device 220-1 sends a handover request to network device 220-2. The switching request is used to switch the terminal device 210-1 to the network device 220-2. The handover request includes a mapping relationship between the identifier of the terminal device 210-2 and the identifier of the radio bearer corresponding to the terminal device 210-2. Terminal device 210-1 relays communications between terminal device 210-2 and network device 220-1.

At block 1220, the network device 220-1 sends a first indication to the terminal device 210-1. The first instruction is used to instruct the terminal device 210-1 to switch from the network device 220-1 to the network device 220-2.

At block 1230, the network device 220-1 receives third data from the network device 220-2. The third data includes data from a remote terminal device.

In some embodiments, the third data also includes data from the network device 220-1. In some embodiments, the network device 220-1 establishes a user plane tunnel with the network device 220-2 based on the mapping relationship, so as to transmit the third data. In some embodiments, the establishment of the user plane tunnel by the network device 220-1 includes one of the following: the network device 220-1 configures a user plane tunnel multiplexed between multiple terminal devices 210-2; or the network device 220- 1. Configure a user plane tunnel in which multiple radio bearers of one terminal device 210-2 are multiplexed; or the network device 220-1 separately configures a user plane tunnel for each radio bearer.

In some embodiments, if it is determined that the user plane tunnel is multiplexed among multiple terminal devices 210-2, the third data includes the identifier of the terminal device 210-2 and the identifier of the radio bearer corresponding to the terminal device 210-2 . If it is determined that the user plane tunnel is multiplexed among multiple radio bearers of one terminal device 210-2, the third data includes the identifier of the radio bearer corresponding to the terminal device 210-2.

In some embodiments, network device 220-1 receives the fourth indication from network device 220-2. The fourth indication is used to indicate the completion of the third data transmission.

FIG. 13 shows a flowchart of a method 1300 according to some embodiments of the present disclosure. As an example, method 1300 can be implemented at a target network device. For example, method 1300 may be implemented at network device 220-2. By way of example only, method 1300 is described with reference to FIG. 2 .

At block 1310, network device 220-2 receives a handover request from network device 220-1. The switching request is used to switch the terminal device 210-1 to the network device 220-2. Terminal device 210-1 relays communications between terminal device 210-2 and network device 220-1.

At block 1320, the network device 220-2 receives third data from the terminal device 210-1. The third data includes data from a remote terminal device.

At block 1330, the network device 220-2 sends third data to the network device 220-1. In some embodiments, the third data also includes data from the network device 220-1.

In some embodiments, the network device 220-2 receives the third data from the terminal device 210-1 through a radio link control layer bearer. In some embodiments, if it is determined that the radio link control layer bearer is multiplexed among multiple terminal devices 210-2, the third data includes the identifier of the terminal device 210-2 and the corresponding The identity of the radio bearer. If it is determined that the radio link control layer bearer is multiplexed among multiple radio bearers of one terminal device 210-2, the third data includes the identifier of the radio bearer corresponding to the terminal device 210-2.

In some embodiments, the network device 220-2 establishes a user plane tunnel with the network device 220-1. The network device 220-2 sends the third data to the network device 220-1 through the user plane tunnel.

In some embodiments, after the network device 220-2 finishes sending the third data, the target network sends the fifth indication to the network device 220-1. The fifth indication is used to indicate the completion of the transmission of the third data.

FIG. 14 shows a flowchart of a method 1400 according to some embodiments of the present disclosure. As an example, the method 1400 may be implemented at a relay terminal device. For example, method 1400 may be implemented at terminal device 210-1. By way of example only, method 1400 is described with reference to FIG. 2 .

At block 1410, the terminal device 210-1 relays communications between the terminal device 210-2 and the network device 220-1.

At block 1420, the terminal device 210-1 receives a sixth indication from the network device 220-1. The sixth indication is used to instruct the terminal device 210-2 to reselect a cell or a relay terminal device.

At block 1430, the terminal device 210-1 sends a sixth indication to the terminal device 210-2.

At block 1440, the terminal device 210-1 sends the sixth data from the terminal device 210-2 to the network device 220-1.

In some embodiments, after the terminal device 210-1 sends the sixth data, the terminal device 210-1 sends the seventh indication to the network device 220-1. The seventh indication is used to indicate the completion of the transmission of the sixth data.

In some embodiments, the terminal device 210-1 sends the seventh data from the network device 220-1 to the terminal device 210-2. After the terminal device 210-1 sends the seventh data, the terminal device 210-1 releases the sidelink with the terminal device 210-2.

In some embodiments, the sixth indication includes an identity of a target cell of the remote terminal device or a target relay terminal device.

FIG. 15 shows a flowchart of a method 1500 according to some embodiments of the present disclosure. As an example, the method 1500 may be implemented at a relay terminal device. For example, method 1500 may be implemented at terminal device 210-1. By way of example only, method 1500 is described with reference to FIG. 2 .

At block 1510, the relay terminal device relays communications between the terminal device 210-2 and the network device 220-1.

At block 1520, the terminal device 210-1 receives a first indication from the network device 220-1. The first instruction is used to instruct the terminal device 210-1 to switch from the network device 220-1 to the network device 220-2.

At block 1530, the terminal device 210-1 establishes a connection with the network device 220-2 based on the first indication while maintaining the connection with the network device 220-1.

At block 1540, the terminal device 210-1 sends the first data from the network device 220-1 to the terminal device 210-2.

In some embodiments, after the terminal device 210-1 receives the first indication, the terminal device 210-1 sends the second indication to the terminal device 210-2. The second instruction is used to instruct the terminal device 210-2 to stop sending data to the network device 220-1.

In some embodiments, after the terminal device 210-1 sends the first data, the terminal device 210-1 releases the sidelink with the terminal device 210-2.

In some embodiments, the terminal device 210-1 sends the third data to the network device 220-1. The third data includes data from a remote terminal device. In some embodiments, after the terminal device 210-1 sends the third data, the terminal device 210-1 sends the third indication to the network device 220-1. The third indication is used to indicate the completion of the transmission of the third data.

FIG. 16 shows a flowchart of a method 1600 according to some embodiments of the present disclosure. As an example, method 1600 may be implemented at a source network device. For example, method 1600 may be implemented at network device 220-1. By way of example only, method 1600 is described with reference to FIG. 2 .

In block 1610, the network device 220-1 determines that the relay terminal device will perform cell handover.

In block 1620, the network device 220-1 sends a sixth indication to the terminal device 210-1, where the sixth indication is used to instruct the terminal device 210-2 to reselect a cell or a relay terminal device.

At block 1630, the network device 220-1 receives sixth data from the terminal device 210-2 from the terminal device 210-1.

In some embodiments, after the terminal device 210-1 sends the sixth data, the network device 220-1 receives the seventh indication from the terminal device 210-1. The seventh indication is used to indicate the completion of the transmission of the sixth data.

In some embodiments, the sixth indication includes an identity of a target cell of the remote terminal device or a target relay terminal device.

FIG. 17 shows a flowchart of a method 1700 according to some embodiments of the present disclosure. As an example, method 1700 can be implemented at a target network device. For example, method 1800 may be implemented at network device 220-1. By way of example only, method 1700 is described with reference to FIG. 2 .

At block 1710, network device 220-1 sends a handover request to network device 220-2. The switching request is used to switch the relay terminal device to the network device 220-2. The handover request includes a mapping relationship between the identifier of the terminal device 210-2 and the identifier of the radio bearer corresponding to the terminal device 210-2. Terminal device 210-1 relays communications between terminal device 210-2 and network device 220-1.

At block 1720, the network device 220-1 sends a first indication to the terminal device 210-1. The first instruction is used to instruct the terminal device 210-1 to switch from the network device 220-1 to the network device 220-2.

At block 1730, the network device 220-1 receives third data from the terminal device 210-1. The third data includes data from a remote terminal device.

In some embodiments, after the terminal device 210-1 sends the third data, the network device 220-1 receives a third indication from the terminal device 210-1, where the third indication is used to indicate the completion of the transmission of the third data. In some embodiments, the network device 220-1 releases the RRC connection with the terminal device 210-1.

FIG. 18 shows a flowchart of a method 1800 according to some embodiments of the present disclosure. As an example, method 1800 may be implemented at a remote terminal device. For example, method 1800 may be implemented at terminal device 210-2. By way of example only, method 1800 is described with reference to FIG. 2 .

At block 1810, the terminal device 210-2 receives a sixth indication from the relay terminal device. The sixth instruction is used to instruct the terminal device 210-2 to reselect a cell or a relay terminal device, and the terminal device 210-2 accesses the network device 220-1 via the terminal device 210-1.

At block 1820, the terminal device 210-2 receives seventh data from the network device 220-1 from the terminal device 210-1.

At block 1830, the terminal device 210-1 releases the sidelink with the terminal device 210-2.

In some embodiments, the sixth indication includes an identification of a target cell or a target relay terminal device of the remote terminal device. FIGS. 19A to 19D show schematic block diagrams of communication devices according to some embodiments of the present disclosure. The communication means may be implemented as a device or a chip in a device, and the scope of the present disclosure is not limited in this respect.

The communication device 1910 shown in FIG. 19A may be implemented at a relay terminal device. The communication device 1910 includes: a relay unit 1911 , a receiving unit 1912 , a switching unit 1913 and a sending unit 1914 . The relay unit 1911 is used to relay the communication between the remote terminal device and the source network device. The receiving unit 1912 is configured to receive the first indication from the source network device. The first indication is used to instruct the relay terminal device to switch from the source network device to the target network device. The receiving unit 1912 may also receive a sixth indication from the source network device. The sixth indication is used to instruct the remote terminal device to reselect a cell or a relay terminal device. The switching unit 1913 is configured to perform switching based on the first indication. The switching unit 1913 can also maintain the connection with the source network device at the same time. The sending unit 1914 is configured to send the first data from the source network device to the remote terminal device. The sending unit 1914 may also be configured to send third data to the target network device. The third data includes data from the remote terminal device. The sending unit 1914 may also send a sixth indication to the remote terminal device. The sending unit may also send sixth data from the remote terminal device to the source network device. The communication device 1910 may further include other units, configured to implement the methods described in FIG. 3 to FIG. 9 , FIG. 10 , FIG. 11 , FIG. 14 and FIG. 15 .

The communication device 1920 shown in FIG. 19B may be implemented at the source network device. The communication device 1920 includes: a first sending unit 1921 , a second sending unit 1922 and a receiving unit 1923 . The first sending unit 1921 is configured to send a switching request to the target network device, where the switching request is used to switch the relay terminal device to the target network device. The second sending unit 1922 sends a first indication to the relay terminal device, where the first indication is used to instruct the relay terminal device to switch from the source network device to the target network device. The receiving unit 1923 receives third data from the target network device, where the third data includes data from the remote terminal device. The communication device 1920 may further include other units, configured to implement the methods described in FIG. 3 to FIG. 9 , FIG. 12 , FIG. 16 and FIG. 17 .

The communication device 1930 shown in FIG. 19C can be implemented at the target network device. The communication device 1930 includes: a first receiving unit 1931 , a second receiving unit 1932 and a sending unit 1933 . The first receiving unit 1931 is configured to receive a switching request from the source network device, where the switching request is used to switch the relay terminal device to the target network device. The second receiving unit 1932 is configured to receive third data from the relay terminal device, where the third data includes data from the remote terminal device. The sending unit 1933 is configured to send the third data to the source network device. The communication device 1930 may further include other units, configured to implement the methods described in FIG. 3 to FIG. 9 and FIG. 13 .

The communication device 1940 shown in FIG. 19D can be implemented at the target network device. The communication device 1940 includes: a first receiving unit 1941 , a second receiving unit 1942 and a releasing unit 1943 . The first receiving unit 1941 is configured to receive a sixth indication from the relay terminal device, where the sixth indication is used to instruct the remote terminal device to reselect a cell or the relay terminal device. The second receiving unit 1942 is configured to receive seventh data from the source network device. The releasing unit 1943 is used to release the side link with the remote terminal device. The communication device 1930 may further include other units, configured to implement the methods described in FIG. 3 to FIG. 9 and FIG. 18 .

FIG. 20 is a simplified block diagram of an example device 2000 suitable for implementing embodiments of the present disclosure. The device 2000 can be used to realize the terminal device, the access network device and one or more core network devices/network functions as shown in FIG. 1 . As shown, the device 2000 includes one or more processors 2010 , one or more memories 2020 coupled to the processors 2010 , and a communication module 2040 coupled to the processors 2010 .

The communication module 2040 can be used for two-way communication. The communication module 2040 may have at least one communication interface for communication. Communication interfaces may include any interface necessary to communicate with other devices.

The processor 2010 can be any type suitable for the local technical network, and can include but not limited to at least one of the following: a general-purpose computer, a special-purpose computer, a microcontroller, a digital signal processor (Digital SignalProcessor, DSP), or based on a controller One or more of the multi-core controller architectures. Device 2000 may have multiple processors, such as application specific integrated circuit chips, that are time slaved to a clock that is synchronized with the main processor.

Memory 2020 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memory include but are not limited to at least one of the following: read-only memory (Read-Only Memory, ROM) 2024, erasable programmable read-only memory (Erasable Programmable Read Only Memory, EPROM), flash memory, hard disk , Compact Disc (CD), Digital Video Disk (Digital Versatile Disc, DVD) or other magnetic storage and/or optical storage. Examples of volatile memory include, but are not limited to, at least one of: Random Access Memory (RAM) 2022, or other volatile memory that does not persist for the duration of a power outage.

The computer program 2030 comprises computer-executable instructions executed by the associated processor 2010 . The program 2030 can be stored in the ROM 2020 . Processor 2010 may perform any suitable actions and processes by loading programs 2030 into RAM 2020 .

Embodiments of the present disclosure may be implemented by means of the program 2030 such that the device 2000 may perform any process as discussed with reference to FIGS. 2 to 5 . Embodiments of the present disclosure can also be realized by hardware or by a combination of software and hardware.

In some embodiments, program 2030 may be tangibly embodied on a computer readable medium, which may be included in device 2000 (such as in memory 2020 ) or other storage device accessible by device 2000 . Program 2030 may be loaded from a computer readable medium into RAM 2022 for execution. The computer readable medium may include any type of tangible nonvolatile memory such as ROM, EPROM, flash memory, hard disk, CD, DVD, and the like.

In general, the various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software, which may be executed by a controller, microprocessor or other computing device. While various aspects of the embodiments of the present disclosure are shown and described as block diagrams, flowcharts, or using some other pictorial representation, it should be understood that the blocks, devices, systems, techniques or methods described herein can be implemented as, without limitation, Exemplary, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controllers or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product comprises computer-executable instructions, such as included in program modules, which are executed in a device on a real or virtual processor of a target to perform the process/method as described above with reference to FIGS. 3 to 18 . Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In various embodiments, the functionality of the program modules may be combined or divided as desired among the program modules. Machine-executable instructions for program modules may be executed within local or distributed devices. In a distributed device, program modules may be located in both local and remote storage media.

Computer program codes for implementing the methods of the present disclosure may be written in one or more programming languages. These computer program codes can be provided to processors of general-purpose computers, special-purpose computers, or other programmable data processing devices, so that when the program codes are executed by the computer or other programmable data processing devices, The functions/operations specified in are implemented. The program code may execute entirely on the computer, partly on the computer, as a stand-alone software package, partly on the computer and partly on a remote computer or entirely on the remote computer or server.

In the context of the present disclosure, computer program code or related data may be carried by any suitable carrier to enable a device, apparatus or processor to perform the various processes and operations described above. Examples of carriers include signals, computer readable media, and the like. Examples of signals may include electrical, optical, radio, sound, or other forms of propagated signals, such as carrier waves, infrared signals, and the like.

A computer readable medium may be any tangible medium that contains or stores a program for or related to an instruction execution system, apparatus, or device. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination thereof. More detailed examples of computer-readable storage media include electrical connections with one or more wires, portable computer diskettes, hard disks, random storage access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash), optical storage, magnetic storage, or any suitable combination thereof.

In addition, while operations of methods of the present disclosure are depicted in a particular order in the figures, this does not require or imply that operations must be performed in that particular order, or that all illustrated operations must be performed, to achieve desirable results. Conversely, the steps depicted in the flowcharts may be performed in an altered order. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step for execution, and/or one step may be decomposed into multiple steps for execution. It should also be noted that the features and functions of two or more devices according to the present disclosure may be embodied in one device. Conversely, the features and functions of one device described above may be further divided to be embodied by a plurality of devices.

Having described various implementations of the present disclosure, the foregoing description is exemplary, not exhaustive, and is not limited to the disclosed implementations. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described implementations. The choice of terminology used herein aims to well explain the principle of each implementation, practical application or improvement to the technology in the market, or to enable other ordinary skilled persons in the technical field to understand the various implementations disclosed herein.

Claims (29)

1. A method for communication, characterized in that the method comprises: The relay terminal device relays the communication between the remote terminal device and the source network device; The relay terminal device receives a first indication from the source network device, where the first indication is used to instruct the relay terminal device to switch from the source network device to a target network device; performing handover by the relay terminal device based on the first indication; and The relay terminal device sends the first data from the source network device to the remote terminal device. 2. The method according to claim 1, characterized in that the method further comprises: After the relay terminal device receives the first indication, the relay terminal device sends a second indication to the remote terminal device, and the second indication is used to instruct the remote terminal device to stop sending The source network device sends data. 3. The method according to claim 1 or 2, characterized in that the method further comprises: After the relay terminal device sends the first data, the relay terminal device releases the sidelink with the remote terminal device. 4. method according to claim 1 or 2, is characterized in that, described method also comprises: The relay terminal device sends second data to the remote terminal device, where the second data comes from the remote terminal device. 5. The method according to claim 4, wherein the sending of the second data by the relay terminal device to the remote terminal device comprises: The relay terminal device sends the second data through a sidelink between the relay terminal device and the remote terminal device. 6. The method according to claim 5, further comprising: Before the relay terminal device sends the second data, the relay terminal device adds an identifier to the second data, where the identifier is used to indicate that the second data comes from the remote terminal device. 7. The method according to claim 4, characterized in that the method further comprises: The relay terminal device establishes a first sidelink bearer, where the first sidelink bearer is used for transmission of the second data. 8. The method according to any one of claims 4-7, wherein the method further comprises: After the relay terminal device sends the first data and the second data, the relay terminal device releases the sidelink with the remote terminal device. 9. A method for communication, characterized in that the method comprises: The relay terminal device relays the communication between the remote terminal device and the source network device; The relay terminal device receives a first indication from the source network device, where the first indication is used to instruct the relay terminal device to switch from the source network device to a target network device; performing handover by the relay terminal device based on the first indication; and The relay terminal device sends third data to the target network device, where the third data includes data received from the remote terminal device before receiving the first indication. 10. The method according to claim 9, wherein said third data further comprises data from said source network device. 11. The method according to claim 9, further comprising: The relay terminal device establishes one or more radio link control layer bearers based on the bearer configuration in the first indication; and The sending of the third data by the relay terminal device to the target network device includes: The relay terminal device sends the third data through the one or more radio link control layer bearers. 12. The method of claim 11, wherein: If it is determined that multiple remote terminal devices multiplex the radio link control layer bearer, before the relay terminal device sends the third data, the relay terminal device adds the remote an identifier of the terminal device and an identifier of the bearer of the remote terminal device; or If it is determined that multiple bearers of a remote terminal device are multiplexed with radio link control layer bearers, before the relay terminal device sends the third data, the relay terminal device adds the The identifier of the bearer of the remote terminal device. 13. The method according to any one of claims 9-12, further comprising: After the relay terminal device sends the third data, the relay terminal device sends a third indication to the target network device, where the third indication is used to indicate the completion of the transmission of the third data . 14. A method for communication, characterized in that the method comprises: The source network device sends a switch request to the target network device, the switch request is used to switch the relay terminal device to the target network device, and the switch request includes the identity of the remote terminal device and the A mapping relationship between identities of radio bearers, where the relay terminal device relays the communication between the remote terminal device and the source network device; The source network device sends a first indication to the relay terminal device, where the first indication is used to instruct the relay terminal device to switch from the source network device to a target network device; and The source network device receives third data from the target network device, the third data including data from the remote terminal device. 15. The method according to claim 14, wherein the third data further comprises data from the source network device, wherein the method further comprises: The source network device respectively receives the data from the remote terminal device and the data from the source network device from the target network device through different user plane tunnels; or The source network device receives the data from the remote terminal device and the data from the source network device from the target network device through the same user plane tunnel, and the third data includes an identifier for distinguishing the data from the source network device data from the remote terminal device and data from the source network device. 16. The method according to claim 14 or 15, further comprising: The source network device establishes a user plane tunnel with the target network device based on the mapping relationship, for transmission of the third data; The establishment of the user plane tunnel by the source network device includes the following items: The source network device configures the user plane tunnel that is multiplexed among multiple remote terminal devices; or The source network device configures the user plane tunnel in which multiple radio bearers of a remote terminal device are multiplexed; or The source network device separately configures a user plane tunnel for each radio bearer. 17. The method according to claim 16, wherein the third data comprises one of the following: If it is determined that the user plane tunnel is multiplexed among multiple remote terminal devices, the third data includes an identifier of the remote terminal device and an identifier of a radio bearer corresponding to the remote terminal device; or If it is determined that the user plane tunnel is multiplexed among multiple radio bearers of a remote terminal device, the third data includes an identifier of a radio bearer corresponding to the remote terminal device; or If it is determined that the user plane tunnel is not multiplexed among multiple remote terminal devices, the third data does not include an identifier of the remote terminal device and an identifier of a radio bearer corresponding to the remote terminal device . 18. The method of claim 17, further comprising: The source network device transfers the third data to the remote terminal device based on the identifier of the remote terminal device carried by the third data and the identifier of a radio bearer corresponding to the remote terminal device The corresponding end-to-end packet data aggregation layer. 19. The method according to any one of claims 14-18, further comprising: The source network device receives a fourth indication from the target network device, where the fourth indication is used to indicate completion of the third data transmission. 20. A method for communication, characterized in that the method comprises: The target network device receives a handover request from the source network device, the handover request is used to switch the relay terminal device to the target network device, and the relay terminal device controls the communication between the remote terminal device and the source network device Communications are relayed; The target network device receives third data from the relay terminal device, the third data including data from the remote terminal device; and The target network device sends the third data to the source network device. 21. The method according to claim 20, wherein the third data further comprises data from the source network device. 22. The method according to claim 20, wherein the receiving the third data by the target network device from the relay terminal device comprises: The target network device receives the third data from the relay terminal device through a radio link control layer bearer; and in: If it is determined that the radio link control layer bearer is multiplexed among multiple remote terminal devices, the third data includes the identifier of the remote terminal device and the radio bearer corresponding to the remote terminal device logo; or If it is determined that the radio link control layer bearer is multiplexed among multiple radio bearers of a remote terminal device, the third data includes an identifier of the radio bearer corresponding to the remote terminal device; or If it is determined that the radio link control layer bearer is not multiplexed among multiple remote terminal devices, the third data does not include the identifier of the remote terminal device and the radio link corresponding to the remote terminal device. Bearer ID. 23. The method according to any one of claims 20-22, further comprising: The target network device establishes a user plane tunnel with the source network device; and The target network device sends the third data to the source network device through the user plane tunnel. 24. The method of claim 23, further comprising: The target network device performs at least one of the following based on the multiplexing of the radio link control layer bearer and the multiplexing of the user plane tunnel: retaining the identifier of the remote terminal device and/or the identifier of the radio bearer of the remote terminal device in the third data; adding the identifier of the remote terminal device and/or the identifier of the radio bearer of the remote terminal device to the third data; or Deleting the identity of the remote terminal device and/or the identity of the radio bearer of the remote terminal device from the third data. 25. The method according to any one of claims 20-24, further comprising: After the target network finishes sending the third data, the target network sends a fifth indication to the source network device, where the fifth indication is used to indicate completion of the transmission of the third data. 26. A computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the computer program according to any one of claims 1 to 8, or claims 9 to 13 is implemented. Any one in, or any one in claim 14 to 19, or the described operation of any one method in the claim 20-25. 27. A chip configured to execute any one of claims 1 to 8, or any one of claims 9 to 13, or any one of claims 14 to 19, or any one of claims 20-25. The operations described in any one of the methods. 28. A terminal device, characterized in that the terminal device comprises: at least one processing unit; and at least one memory coupled to the at least one processing unit and storing instructions for execution by the at least one processing unit which, when executed by the at least one processing unit, cause the terminal device to implement A method according to any one of claims 1 to 8, or a method according to any one of claims 9 to 13. 29. A network device, characterized in that the network device comprises: at least one processing unit; and at least one memory coupled to the at least one processing unit and storing instructions for execution by the at least one processing unit that, when executed by the at least one processing unit, cause the network device to implement A method according to any one of claims 14 to 19, or a method according to any one of claims 20-25.

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