Radio terminal, base station, and method therefor

1. A radio terminal comprising:

at least one memory; and

at least one processor coupled to the at least one memory and configured to receive a first information element indicating a list of search spaces configured by a base station for the radio terminal via a dedicated signaling message destined for the radio terminal, wherein

the first information element contains a second information element indicating a configuration of each search space required by the radio terminal to monitor downlink control information in each search space included in the list, and

the first information element further contains a third information element indicating, on a per-search space basis, whether each search space is initially deactivated.

2. The radio terminal according to claim 1 , wherein the at least one processor is configured to determine, on a per-search space basis, whether each search space needs to be monitored to receive downlink control information, based on the third information element.

3. The radio terminal according to claim 1 , wherein

the at least one processor is configured to, if the third information element indicates deactivation, determine that a search space associated with the third information element does not need to be monitored to receive downlink control information, and

the at least one processor is configured to, if the third information element does not indicate deactivation, determine that the search space associated with the third information element needs to be monitored to receive downlink control information.

4. The radio terminal according to claim 1 , wherein the at least one processor is configured to perform a Radio Resource Control (RRC) layer operation,

wherein the RRC layer operation includes, if the third information element indicates deactivation, informing a physical layer of the radio terminal that a search space associated with the third information element does not need to be monitored.

5. The radio terminal according to claim 1 , wherein the at least one processor is configured to perform a Radio Resource Control (RRC) layer operation,

wherein the RRC layer operation includes, if the third information element indicates deactivation, configuring a physical layer of the radio terminal not to monitor a search space associated with the third information element.

6. The radio terminal according to claim 1 , wherein the second information element includes an information element indicating an identifier of each search space.

7. The radio terminal according to claim 1 , wherein the second information element includes at least one of: an information element indicating a resource location of each search space; an information element indicating a type of each search space; an information element indicating a type of downlink control information to be monitored in each search space; or an information element indicating periodicity of each search space.

8. The radio terminal according to claim 1 , wherein

the first information element relates to a configuration of a single downlink Bandwidth Part (BWP), and

the second and third information elements relate to each search space configured within the downlink BWP.

9. The radio terminal according to claim 1 , wherein the dedicated signaling message is a Radio Resource Control (RRC) message.

10. The radio terminal according to claim 9 , wherein

the first information element is a searchSpacesToAddModList information element,

the second information element is a SearchSpace information element included in the searchSpacesToAddModList information element, and

the third information element is contained in the SearchSpace information element.

11. The radio terminal according to claim 1 , wherein the at least one processor is configured to, when the radio terminal is handed over to the base station from another base station, receive the dedicated signaling message via the other base station.

12. A base station comprising:

at least one memory; and

at least one processor coupled to the at least one memory and configured to transmit to a radio terminal a first information element indicating a list of search spaces configured by the base station for the radio terminal via a dedicated signaling message destined for the radio terminal, wherein

the first information element contains a second information element indicating a configuration of each search space required by the radio terminal to monitor downlink control information in each search space included in the list, and

the first information element further contains a third information element indicating, on a per-search space basis, whether each search space is initially deactivated.

13. The base station according to claim 12 , wherein the third information element causes the radio terminal to determine, on a per-search space basis, whether each search space needs to be monitored to receive downlink control information.

14. The base station according to claim 12 , wherein

the third information element causes the radio terminal to, if the third information element indicates deactivation, determine that a search space associated with the third information element does not need to be monitored to receive downlink control information, and

the third information element causes the radio terminal to, if the third information element does not indicate deactivation, determine that the search space associated with the third information element needs to be monitored to receive downlink control information.

15. The base station according to claim 12 , wherein the third information element causes a Radio Resource Control (RRC) of the radio terminal to, if the third information element indicates deactivation, inform a physical layer of the radio terminal that a search space associated with the third information element does not need to be monitored.

16. The base station according to claim 12 , wherein the third information element causes a Radio Resource Control (RRC) of the radio terminal to, if the third information element indicates deactivation, configure a physical layer of the radio terminal not to monitor a search space associated with the third information element.

17. The base station according to claim 12 , wherein the second information element includes an information element indicating an identifier of each search space.

18. The base station according to claim 12 , wherein the second information element includes at least one of: an information element indicating a resource location of each search space; an information element indicating a type of each search space; an information element indicating a type of downlink control information to be monitored in each search space; or an information element indicating periodicity of each search space.

19. The base station according to claim 12 , wherein

the first information element relates to a configuration of a single downlink Bandwidth Part (BWP), and

the second and third information elements relate to each search space configured within the downlink BWP.

20. A method for a radio terminal, the method comprising:

receiving a first information element indicating a list of search spaces configured by a base station for the radio terminal via a dedicated signaling message destined for the radio terminal, wherein

the first information element contains a second information element indicating a configuration of each search space required by the radio terminal to monitor downlink control information in each search space included in the list, and

the first information element further contains a third information element indicating, on a per-search space basis, whether each search space is initially deactivated.