Method for transmitting physical downlink control channel and device

1 . A method for transmitting a physical downlink control channel, comprising:

receiving, by a terminal device, a Physical Downlink Control Channel (PDCCH) from a network device on a first Control Resource Set (CORESET), wherein a Demodulation Reference Signal (DMRS) for the PDCCH corresponds to N active Transmission Configuration Indicator-States (TCI-states), where N=2;

wherein before the terminal device receives the PDCCH from the network device on the first CORESET, the method further comprises:

receiving, by the terminal device, second configuration information from the network device; and

configuring, by the terminal device, M TCI-states for the first CORESET according to the second configuration information, where M≥N and M is an integer;

wherein after the terminal device receives the second configuration information from the network device, the method further comprises:

receiving, by the terminal device, first Medium Access Control Control Element (MAC CE) signaling from the network device, wherein the first MAC CE signaling is used to indicate the N active TCI-states among the M TCI-states;

wherein the first MAC CE signaling comprises:

serving cell indication information used to indicate a serving cell corresponding to the first MAC CE signaling;

CORESET indication information used to indicate a CORESET corresponding to the first MAC CE signaling;

first indication information used to indicate an active TCI-state among the N active TCI-states; and

second indication information used to indicate another active TCI-state among the N active TCI-states;

wherein when the PDCCH schedules a PDSCH, if a scheduling offset is smaller than a first threshold and the terminal device needs to determine a Quasi-co-location (QCL) assumption related to PDSCH reception according to the first CORESET, the terminal device schedules the PDSCH according to a first TCI-state in the N active TCI-states;

wherein the method further comprises:

determining, by the terminal device, the first TCI-state according to positions of respective TCI-states in the N active TCI-states;

wherein the first TCI-state is a TCI-state which has a forward position among the N active TCI-states in the first MAC CE signaling;

wherein the method further comprises:

receiving, by the terminal device, fourth configuration information from the network device, wherein the fourth configuration information is used to indicate that a DMRS for at least part of at least one PDCCH received by the terminal device corresponds to the N active TCI-states.

2 . The method according to claim 1 , wherein the PDCCH corresponds to a first search space, and the first search space is a specific search space (USS) of the terminal device.

3 . The method according to claim 1 , wherein each of the TCI-states comprises the following information:

a state identity (ID) of the TCI-state used to identify a state of the TCI-state; and

first Quasi-co-location (QCL) information;

wherein each of the TCI-states further comprises: second QCL information.

4 . The method according to claim 1 , wherein the first CORESET comprises multiple physical resource blocks in a frequency domain and one to three Orthogonal Frequency Division Multiplexing (OFDM) symbols in a time domain, and the first CORESET is associated with at least one search space.

5 . The method according to claim 1 , wherein an indication field of a Transmission Configuration Indicator (TCI) in Downlink Control Information (DCI) corresponding to the first CORESET is at least one bit; and/or

wherein transmission configuration indication information tci-PresentInDCI corresponding to the first CORESET is in an enable state; and/or

wherein transmission configuration indication information tci-PresentInDCI-1-2 corresponding to the first CORESET is in an enable state.

6 . The method according to claim 1 , wherein a Bandwidth Part (BWP) of the terminal device is configured with P CORESETs, where 1≤P≤5 and P is an integer, and the P CORESETs comprise the first CORESET;

wherein the P is at most 5; or the P is at most 3.

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

sending, by the terminal device, capability information to the network device, wherein the capability information is used to indicate that the terminal device supports receiving a PDCCH corresponding to the N active TCI-states;

wherein the capability information is carried in capability signaling of the terminal device;

or, wherein the capability information is carried in Radio Resource Control (RRC) signaling.

8 . A terminal device, comprising:

a memory storing an executable program code; and

a processor and a transceiver coupled to the memory;

wherein the transceiver is configured to receive Physical Downlink Control Channel (PDCCH) on a first Control Resource Set (CORESET), wherein a Demodulation Reference Signal (DMRS) for the PDCCH corresponds to N active Transmission Configuration Indicator-States (TCI-states), where N=2;

wherein the transceiver is further configured to, before receiving the PDCCH on the first CORESET, receive second configuration information from a network device; and

wherein the processor is further configured to configure M TCI-states for the first CORESET according to the second configuration information, where M≥N and M is an integer;

wherein the transceiver is further configured to, after receiving the second configuration information from the network device, receive first Medium Access Control Control Element (MAC CE) signaling from the network device, wherein the first MAC CE signaling is used to indicate the N active TCI-states among the M TCI-states;

wherein the first MAC CE signaling comprises:

serving cell indication information used to indicate a serving cell corresponding to the first MAC CE signaling;

CORESET indication information used to indicate a CORESET corresponding to the first MAC CE signaling;

first indication information used to indicate an active TCI-state among the N active TCI-states; and

second indication information used to indicate another active TCI-state among the N active TCI-states;

wherein when the PDCCH schedules a PDSCH, if a scheduling offset is smaller than a first threshold and the terminal device needs to determine a Quasi-co-location (QCL) assumption related to PDSCH reception according to the first CORESET, the terminal device schedules the PDSCH according to a first TCI-state in the N active TCI-states;

wherein the processor is further configured to:

determine the first TCI-state according to positions of respective TCI-states in the N active TCI-states;

wherein the first TCI-state is a TCI-state which has a forward position among the N active TCI-states in the first MAC CE signaling;

wherein the transceiver is further configured to:

receive fourth configuration information from the network device, wherein the fourth configuration information is used to indicate that a DMRS for at least part of at least one PDCCH received by the terminal device corresponds to the N active TCI-states.

9 . The device according to claim 8 , wherein the PDCCH corresponds to a first search space, and the first search space is a specific search space (USS) of the terminal device.

10 . The device according to claim 8 , wherein each of the TCI-states comprises the following information:

a state identity (ID) of the TCI-state used to identify a state of the TCI-state; and

first Quasi-co-location (QCL) information;

wherein each of the TCI-states further comprises: second QCL information.

11 . A network device, comprising:

a memory storing an executable program code; and

a transceiver coupled to the memory;

wherein the transceiver is configured to send Physical Downlink Control Channel (PDCCH) to a terminal device on a first Control Resource Set (CORESET), wherein a Demodulation Reference Signal (DMRS) for the PDCCH corresponds to N active Transmission Configuration Indicator-States (TCI-states), where N=2;

wherein the transceiver is configured to, before sending the PDCCH on the first CORESET, send second configuration information to the terminal device; and

wherein the second configuration information is used for configuring M TCI-states for the first CORESET, where M≥N and M is an integer;

wherein the transceiver is further configured to, after sending the second configuration information to the terminal device, send first Medium Access Control Control Element (MAC CE) signaling to the terminal device, wherein the first MAC CE signaling is used to indicate the N active TCI-states among the M TCI-states;

wherein the first MAC CE signaling comprises:

serving cell indication information used to indicate a serving cell corresponding to the first MAC CE signaling;

CORESET indication information used to indicate a CORESET corresponding to the first MAC CE signaling;

first indication information used to indicate an active TCI-state among the N active TCI-states; and

second indication information used to indicate another active TCI-state among the N active TCI-states;

wherein the first MAC CE signaling is used for the terminal device to schedule the PDSCH according to a first TCI-state in the N active TCI-states when the PDCCH schedules a PDSCH and if a scheduling offset is smaller than a first threshold and the terminal device needs to determine a Quasi-co-location (QCL) assumption related to PDSCH reception according to the first CORESET;

wherein the first TCI-state is determined according to positions of respective TCI-states in the N active TCI-states, and the first TCI-state a TCI-state which has a forward position among the N active TCI-states in the first MAC CE signaling;

wherein the transceiver is further configured to:

send fourth configuration information to the terminal device, wherein the fourth configuration information is used to indicate that a DMRS for at least part of at least one PDCCH received by the terminal device corresponds to the N active TCI-states.

12 . The device according to claim 11 , wherein the first CORESET comprises multiple physical resource blocks in a frequency domain and one to three Orthogonal Frequency Division Multiplexing (OFDM) symbols in a time domain, and the first CORESET is associated with at least one search space.

13 . The device according to claim 11 , wherein a control resource set pool index coresetPoolIndex corresponding to the first CORESET is not configured.

14 . The device according to claim 11 , wherein an indication field of a Transmission Configuration Indicator (TCI) in Downlink Control Information (DCI) corresponding to the first CORESET is at least one bit; and/or

wherein transmission configuration indication information tci-PresentInDCI corresponding to the first CORESET is in an enable state; and/or

wherein transmission configuration indication information tci-PresentInDCI-1-2 corresponding to the first CORESET is in an enable state.

15 . The device according to claim 11 , wherein a Bandwidth Part (BWP) of the terminal device is configured with P CORESETs, where 1≤P≤5 and P is an integer, and the P CORESETs comprise the first CORESET;

wherein the P is at most 5; or the P is at most 3.