Handover method, terminal, network device, and relay

1 . A handover method, comprising:

obtaining first indication information from a candidate relay by a terminal;

transmitting the first indication information by the terminal to a source network device to which a source cell belongs, wherein, the first indication information is configured for the source network device to determine a first target cell and/or a first target relay to which the terminal hands over;

obtaining a Radio Resource Control (RRC) reconfiguration message by the terminal;

determining a second target cell and/or a second target relay by the terminal according to the RRC reconfiguration message;

transmitting, through the second target relay, an RRC reconfiguration complete message to a network device to which the second target cell belongs,

wherein the RRC reconfiguration message comprises at least one of the following:

identification information of the second target relay;

identification information of a second target relay link; or

mapping relationship between a sidelink interface Radio Link Control (RLC) channel between the terminal and the second target relay and a second target relay Uu interface RLC channel.

2 . The method according to claim 1 , wherein the first indication information comprises information about candidate cells and/or candidate relays of the terminal,

wherein the first indication information comprises at least one of following:

Public Land Mobile Network (PLMN) identification information corresponding to a candidate cell to which the candidate relay belongs;

cell identification information corresponding to the candidate cell to which the candidate relay belongs;

access mode indication information of accessing the candidate cell by the terminal;

association relation indication information between the candidate relay and the candidate cell;

association relation indication information between a candidate relay link and the candidate cell;

a channel quality measurement result of a Uu interface of the candidate relay;

identification information of the candidate relay;

identification information of the candidate relay link;

moving speed indication information of the candidate relay;

electricity quantity indication information of the candidate relay;

indication information of a service that the candidate relay is capable of serving; or

a channel quality measurement result of a sidelink interface between the candidate relay and the terminal.

3 . The method according to claim 2 , wherein a quantity of candidate relays is N, and N is an integer greater than or equal to 1.

4 . The method according to claim 1 , wherein obtaining the first indication information from the candidate relay by the terminal comprises at least one of following:

obtaining the first indication information by the terminal through a relay discovery related message broadcast by the candidate relay on a sidelink interface;

obtaining the first indication information by the terminal through a sidelink interface Radio Resource Control (PC5-RRC) message, wherein the terminal establishes a sidelink interface unicast connection with the candidate relay.

5 . The method according to claim 1 , further comprising:

transmitting second indication information by the terminal to the source network device to which the source cell belongs, wherein the second indication information comprises at least one of following:

a channel quality measurement result of a sidelink interface between the terminal and a source relay;

moving speed indication information of the source relay;

electricity quantity indication information of the source relay.

6 . The method according to claim 1 , wherein transmitting the first indication information by the terminal to the source network device to which the source cell belongs comprises:

transmitting, by the terminal through a Uu interface, the first indication information to the source network device to which the source cell belongs, or transmitting, by the terminal through the source relay, the first indication information to the source network device to which the source cell belongs.

7 . A terminal, comprising a transceiver, a memory, a processor and a computer program stored on the memory and executable on the processor, wherein when the processor executes the computer program, the processor implements the steps of the handover method according to claim 1 .

8 . A handover method, comprising:

receiving, by a network device, first indication information transmitted by a terminal, wherein the network device is a source network device to which a source cell belongs;

performing a handover decision according to the first indication information by the network device, and determining a first target cell and/or a first target relay to which the terminal is to hand over;

transmitting a Radio Resource Control (RRC) reconfiguration message by the network device to the terminal through a Uu interface or a source relay;

wherein the RRC reconfiguration message comprises at least one of the following:

identification information of a second target relay;

identification information of a second target relay link; or

mapping relationship between a sidelink interface Radio Link Control (RLC) channel between the terminal and the second target relay and a second target relay Uu interface RLC channel.

9 . The method according to claim 8 , further comprising:

transmitting, by the network device, a handover request message to a network device to which the first target cell belongs;

receiving, by the network device, a handover request acknowledge message, wherein the handover request message and/or the handover request acknowledge message comprise at least one of following:

identification information of the terminal;

identification information of the first target relay;

identification information of a first target relay link.

10 . The method according to claim 8 , wherein the first indication information further comprises:

a channel quality measurement result of a sidelink interface between the candidate relay and the terminal.

11 . The method according to claim 8 , further comprising:

receiving, by the network device, second indication information transmitted by the terminal, wherein the second indication information comprises at least one of following:

a channel quality measurement result of a sidelink interface between the terminal and a source relay;

moving speed indication information of the source relay;

power quantity indication information of the source relay.

12 . The method according to claim 8 , wherein the first indication information comprises information about candidate cells and/or candidate relays of the terminal;

wherein the first indication information comprises at least one of following:

Public Land Mobile Network (PLMN) identification information corresponding to a candidate cell to which the candidate relay belongs;

cell identification information corresponding to the candidate cell to which the candidate relay belongs;

access mode indication information of accessing the candidate cell by the terminal;

association relation indication information between the candidate relay and the candidate cell;

association relation indication information between a candidate relay link and the candidate cell;

a channel quality measurement result of a Uu interface of the candidate relay;

identification information of the candidate relay;

identification information of the candidate relay link;

moving speed indication information of the candidate relay;

electricity quantity indication information of the candidate relay;

indication information of a service that the candidate relay is capable of serving; or

a channel quality measurement result of a sidelink interface between the candidate relay and the terminal.

13 . The method according to claim 8 , wherein receiving, by the network device, the first indication information transmitted by the terminal comprises:

receiving, by the network device, through a Uu interface, the first indication information transmitted by the terminal, or receiving, through a source relay, the first indication information transmitted by the terminal.

14 . A network device, the network device being a source network device to which a source cell belongs, the network device comprising a transceiver, a memory, a processor and a computer program stored on the memory and executable on the processor, wherein, when the processor executes the computer program, the processor implements the steps of the handover method according to claim 10 .

15 . A handover method, comprising:

transmitting first indication information by a relay to a terminal, wherein the relay is a candidate relay for handover of the terminal,

wherein, the first indication information is configured for a source network device to determine a first target cell and/or a first target relay to which the terminal hands over, so that the source network device transmits a Radio Resource Control (RRC) reconfiguration message to the terminal through a Uu interface or a source relay, and the RRC reconfiguration message is used by the terminal to determine a second target cell and/or a second target relay according to the RRC reconfiguration message,

wherein the RRC reconfiguration message comprises at least one of the following:

identification information of the second target relay;

identification information of a second target relay link; or

mapping relationship between a sidelink interface Radio Link Control (RLC) channel between the terminal and the second target relay and a second target relay Uu interface RLC channel.

16 . The method according to claim 15 , wherein transmitting the first indication information by the relay to the terminal comprises at least one of following:

broadcasting a relay discovery related message in a sidelink interface by the relay, wherein the relay discovery related message carries the first indication information;

transmitting the first indication information by the relay through a sidelink interface Radio Resource Control (PC5-RRC) message, wherein the terminal establishes a sidelink interface unicast connection with the candidate relay.

17 . The method according to claim 15 , further comprising:

receiving, by the relay, mapping relationship between a sidelink interface Radio Link Control (RLC) channel between the terminal and the first target relay and a first target relay Uu interface RLC channel.

18 . A relay, the relay being a candidate relay for handover of a terminal, the relay comprising a transceiver, a memory, a processor and a computer program stored on the memory and executable on the processor, wherein, when the processor executes the computer program, the processor implements the steps of the handover method according to claim 15 .

19 . The handover method according to claim 15 , wherein, the first indication information comprises information about candidate cells and/or candidate relays of the terminal, wherein the first indication information comprises at least one of following:

access mode indication information of accessing the candidate cell by the terminal;

association relation indication information between the candidate relay and the candidate cell;

association relation indication information between a candidate relay link and the candidate cell;

a channel quality measurement result of a Uu interface of the candidate relay;

identification information of the candidate relay;

identification information of the candidate relay link;

moving speed indication information of the candidate relay;

electricity quantity indication information of the candidate relay;

indication information of a service that the candidate relay is capable of serving; or

a channel quality measurement result of a sidelink interface between the candidate relay and the terminal.