Signal transmission method, related device, and system

1. A signal transmission method, comprising:

sending, after a link failure occurs, by a terminal device, link reconfiguration request information to a network device at a moment n;

receiving, by the terminal device, first signaling sent by the network device at a second moment, wherein the first signaling indicates first information that comprises quasi co-location (QCL) information of a first reference signal and a second reference signal, the first reference signal is used to demodulate a physical downlink control channel (PDCCH), the first reference signal comprises a demodulation reference signal (DMRS), the second reference signal comprises a channel state information reference signal (CSI-RS) or a synchronization signal block (SSB), and a channel quality of the second reference signal is equal to or higher than a first threshold; and

detecting, after sending the link reconfiguration request information, by the terminal device based on the QCL information of the PDCCH indicated by the first information, the PDCCH during a first time period after the moment n and until the second moment, wherein the second moment is an end moment of the first time period, wherein detecting the PDCCH based on the QCL information of the PDCCH indicated by the first information comprises:

using one or more specific receive beams to receive the second reference signal; and

using the same one or more specific receive beams to receive or demodulate the PDCCH.

2. The method according to claim 1 , wherein the second reference signal comprises a downlink reference signal associated with the link reconfiguration request information.

3. The method according to claim 1 ,

wherein the first signaling comprises at least one of radio resource control (RRC) signaling, Media Access Control control element (MAC CE) signaling, or downlink control information (DCI) signaling.

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

detecting, by the terminal device, a first control resource set during the first time period, wherein the first control resource set is configured by the network device for the terminal device and used to send link reconfiguration response information.

5. The method according to claim 4 , further comprising:

detecting, by the terminal device, a second control resource set after the end moment of the first time period, wherein the second control resource set is a resource set in which a link failure occurs.

6. A terminal device, comprising:

at least one processor; and

a non-transitory computer-readable storage medium coupled to the at least one processor and storing programming instructions for execution by the at least one processor, wherein the programming instructions instruct the at least one processor to:

send, after a link failure occurs, link reconfiguration request information to a network device at a moment n;

receive first signaling sent by the network device at a second moment, wherein the first signaling indicates first information that comprises quasi co-location (QCL) information of a first reference signal and a second reference signal, the first reference signal is used to demodulate a physical downlink control channel (PDCCH), the first reference signal comprises a demodulation reference signal (DMRS), the second reference signal comprises a channel state information reference signal (CSI-RS) or a synchronization signal block (SSB), and a channel quality of the second reference signal is equal to or higher than a first threshold; and

detect, after sending the link reconfiguration request information, based on the QCL information of the PDCCH indicated by the first information, the PDCCH during a first time period after the moment n and until the second moment, wherein the second moment is an end moment of the first time period, wherein detecting the PDCCH based on the QCL information of the PDCCH indicated by the first information comprises:

using one or more specific receive beams to receive the second reference signal; and

using the same one or more specific receive beams to receive or demodulate the PDCCH.

7. The terminal device according to claim 6 , wherein the second reference signal comprises a downlink reference signal associated with the link reconfiguration request information.

8. The terminal device according to claim 6 , wherein the first signaling comprises at least one of radio resource control RRC signaling, Media Access Control control element MAC CE signaling, or downlink control information DCI signaling, and the first signaling is used to indicate QCL information of the PDCCH.

9. The terminal device according to claim 6 , wherein the programming instructions instruct the at least one processor to detect a first control resource set during the first time period, wherein the first control resource set is configured by the network device for the terminal device and used to send link reconfiguration response information.

10. The terminal device according to claim 9 , wherein the programming instructions instruct the at least one processor to detect a second control resource set after the end moment of the first time period, wherein the second control resource set is a resource set in which a link failure occurs.

11. A communications system, comprising:

a terminal device; and

a network device,

wherein the terminal device comprises at least one processor; and a non-transitory computer-readable storage medium coupled to the at least one processor and storing programming instructions for execution by the at least one processor, wherein the programming instructions instruct the at least one processor to:

send, after a link failure occurs, link reconfiguration request information to the network device at a moment n;

receive first signaling sent by the network device at a second moment, wherein the first signaling indicates first information that comprises quasi co-location (QCL) information of a first reference signal and a second reference signal, the first reference signal is used to demodulate a physical downlink control channel (PDCCH), the first reference signal comprises a demodulation reference signal (DMRS), the second reference signal comprises a channel state information reference signal (CSI-RS) or a synchronization signal block (SSB), and a channel quality of the second reference signal is equal to or higher than a first threshold; and

detect, after sending the link reconfiguration request information, based on the QCL information of the PDCCH indicated by the first information, the PDCCH during a first time period after the moment n and until the second moment, wherein the second moment is an end moment of the first time period, wherein detecting the PDCCH based on the QCL information of the PDCCH indicated by the first information comprises:

using one or more specific receive beams to receive the second reference signal; and

using the same one or more specific receive beams to receive or demodulate the PDCCH.

12. A non-transitory computer-readable storage medium having instructions recorded thereon which, when executed by at least one processor, cause the at least one processor to perform operations comprising:

sending, after a link failure occurs, by a terminal device, link reconfiguration request information to a network device at a moment n;

receiving first signaling sent by the network device at a second moment, wherein the first signaling indicates first information that comprises quasi co-location (QCL) information of a first reference signal and a second reference signal, the first reference signal is used to demodulate a physical downlink control channel (PDCCH), the first reference signal comprises a demodulation reference signal (DMRS), the second reference signal comprises a channel state information reference signal (CSI-RS) or a synchronization signal block (SSB), and a channel quality of the second reference signal is equal to or higher than a first threshold; and

detecting, after sending the link reconfiguration request information, by the terminal device based on the QCL information of the PDCCH indicated by the first information, the PDCCH during a first time period after the moment n and until the second moment, wherein the second moment is an end moment of the first time period, wherein detecting the PDCCH based on the QCL information of the PDCCH indicated by the first information comprises:

using one or more specific receive beams to receive the second reference signal; and

using the same one or more specific receive beams to receive or demodulate the PDCCH.

13. A communication device, comprising:

one or more memories configured to store instructions; and

one or more processors configured to execute the instructions to performs operations comprising:

sending, after a link failure occurs, by a terminal device, link reconfiguration request information to a network device at a moment n;

receiving first signaling sent by the network device at a second moment, wherein the first signaling indicates first information that comprises quasi co-location (QCL) information of a first reference signal and a second reference signal, the first reference signal is used to demodulate a physical downlink control channel (PDCCH), the first reference signal comprises a demodulation reference signal (DMRS), the second reference signal comprises a channel state information reference signal (CSI-RS) or a synchronization signal block (SSB), and a channel quality of the second reference signal is equal to or higher than a first threshold; and

detecting, after sending the link reconfiguration request information, by the terminal device based on the QCL information of the PDCCH indicated by the first information, the PDCCH during a first time period after the moment n and until the second moment, wherein the second moment is an end moment of the first time period, wherein detecting the PDCCH based on the QCL information of the PDCCH indicated by the first information comprises:

using one or more specific receive beams to receive the second reference signal; and

using the same one or more specific receive beams to receive or demodulate the PDCCH.