Method and device for PDCCH monitoring

1. A method for monitoring a physical downlink control channel (PDCCH), comprising:

monitoring, by a terminal device, the PDCCH according to first configuration information, wherein the first configuration information is used for indicating a first PDCCH search space for monitoring the PDCCH; and

performing, by the terminal device, extra PDCCH monitoring according to second configuration information after a first monitoring time point if downlink control information (DCI) is detected by the terminal device at the first monitoring time point in the first PDCCH search space; wherein the second configuration information is used for indicating a second PDCCH search space for performing the extra PDCCH monitoring; wherein the method further comprises:

receiving, by the terminal device, radio resource control (RRC) signaling, a medium access control control element (MAC CE) or a broadcast message, carrying the second configuration information.

2. The method of claim 1 , wherein performing, by the terminal device, the extra PDCCH monitoring after the first monitoring time point, comprises:

performing, by the terminal device, the extra PDCCH monitoring after the first monitoring time point according to a first timer.

3. The method of claim 2 , further comprising:

receiving, by the terminal device, configuration information of the first timer; or,

obtaining, by the terminal device, configuration information of the first timer pre-stored in the terminal device,

wherein receiving, by the terminal device, the configuration information of the first timer sent by a network device, comprises:

receiving, by the terminal device, radio resource control (RRC)signaling, a medium access control control element (MAC CE) or a broadcast message, carrying the configuration information of the first timer.

4. A method for monitoring a physical downlink control channel (PDCCH), comprising:

sending, by a network device, first configuration information to a terminal device, wherein the first configuration information indicates a first PDCCH search space for monitoring the PDCCH,

sending, by the network device, second configuration information, wherein the second configuration information is used for indicating a second PDCCH search space for a terminal device to perform extra PDCCH monitoring, wherein the extra PDCCH monitoring is performed by the terminal device after a first monitoring time point, and the first monitoring time point is a time point when downlink control information (DCI) is detected by the terminal device in a first PDCCH search space,

wherein sending, by the network device, the second configuration information, comprises:

sending, by the network device, radio resource control (RRC) signaling or a medium access control control element (MAC CE) carrying the second configuration information.

5. A terminal device, comprising: a processor and a transceiver, wherein

the processor is configured to monitor a physical downlink control channel (PDCCH) according to first configuration information, wherein the first configuration information is used for indicating a first PDCCH search space for monitoring the PDCCH;

wherein the processor is further configured to, perform extra PDCCH monitoring according to second configuration information after a first monitoring time point if downlink control information (DCI) is detected by the terminal device at the first monitoring time point in the first PDCCH search space; wherein the second configuration information is used for indicating a second PDCCH search space for performing the extra PDCCH monitoring; wherein the transceiver is further configured to:

receive radio resource control (RRC) signaling, a medium access control control element (MAC CE) or a broadcast message, carrying the second configuration information.

6. A network device, comprising: a processor and a transceiver, wherein

the processor is configured to generate first and second configuration information, wherein the first configuration information indicates the first PDCCH search space for monitoring first PDCCH, and the second configuration information is used for indicating a second PDCCH search space for a terminal device to perform extra PDCCH monitoring, wherein the extra PDCCH monitoring is performed by the terminal device after a first monitoring time point, and the first monitoring time point is a time point when downlink control information (DCI) is detected by the terminal device in a first PDCCH search space;

the transceiver is configured to send the second configuration information,

wherein the transceiver is further configured to:

send radio resource control (RRC) signaling or a medium access control control element (MAC CE) carrying the second configuration information.

7. The method of claim 2 , wherein performing, by the terminal device, the extra PDCCH monitoring after the first monitoring time point according to a first timer, comprises:

stopping, by the terminal device, performing the extra PDCCH monitoring when the first timer expires or the number of times, recorded by the terminal device, that the DCI is not detected by the terminal device, exceeds a threshold.

8. The method of claim 7 , wherein after stopping, by the terminal device, performing the extra PDCCH monitoring, the method further comprises:

continuing, by the terminal device, to perform monitoring PDCCH in the first PDCCH search space.

9. The method of claim 8 , further comprising:

restarting, by the terminal device, the first timer when DCI is detected by the terminal device; and/or

continuing, by the terminal device, running the first timer, that the DCI is not detected by the terminal device.

10. The method of claim 2 , wherein the first timer is started at the first monitoring time point.

11. The terminal device of claim 5 , wherein the processor is specifically configured to:

perform the extra PDCCH monitoring after the first monitoring time point according to a first timer.

12. The terminal device of claim 11 , wherein the processor is specifically configured to:

stop performing the extra PDCCH monitoring when the first timer expires or the number of times, recorded by the terminal device, that the DCI is not detected by the terminal device, exceeds a threshold.

13. The terminal device of claim 12 , wherein after the processor is configured to stop performing the extra PDCCH monitoring, the processor is specifically configured to:

continue to perform monitoring PDCCH in the first PDCCH search space.

14. The terminal device of claim 12 , wherein the processor is further configured to:

restart the first timer when DCI is detected by the terminal device; and/or

continue to run the first timer that the DCI is not detected by the terminal device.

15. The terminal device of claim 12 , wherein the first timer is started at the first monitoring time point.