Method of transmitting and receiving downlink control channel and apparatus therefor

A user equipment (UE) comprising:

• at least one transceiver;
• at least one processor;
• and
• at least one memory operably connected to the at least one processor and configured to store instructions that, when executed, cause the at least one processor to perform operations comprising:
• receiving, through higher layer signaling, configuration information for search space (SS) sets including a first SS set and one or more second SS sets;
• monitoring first physical downlink control channel (PDCCH) candidates in the first SS set to detect first downlink control information (DCI);
• based on that the first DCI is detected, monitoring second PDCCH candidates in the SS sets including the first SS set and the one or more second SS sets to detect second DCI;
• and after detecting the second DCI as a result of the monitoring the second PDCCH candidates, determining, based on a SS set in which the second DCI is detected, at least one SS set to be used for subsequent PDCCH candidate monitoring
• wherein the SS set in which the second DCI is detected is one of the first SS set and the one or more second SS sets.

A base station comprising:

• at least one transceiver;
• at least one processor;
• and
• at least one memory operably connected to the at least one processor and configured to store instructions that, when executed, cause the at least one processor to perform operations comprising:
• transmitting, through higher layer signaling, configuration information for search space (SS) sets including a first SS set and one or more second SS sets;
• transmitting first downlink control information (DCI) based on a first physical downlink control channel (PDCCH) candidate determined in the first SS set;
• transmitting second DCI based on a second PDCCH candidate determined in the SS sets including the first SS set and the one or more second SS sets;
• and
• determining, based on a SS set used for transmitting the second DCI, at least one SS set to be used for subsequent DCI transmission, wherein the SS set used for transmitting the second DCI is one of the first SS set and the one or more second SS sets.