Method and apparatus for processing downlink HARQ process in carrier aggregation
AssigneeNEC Corporation
InventorKengo Oketani
Life of this patent
Estimating the term…
Abstract
A radio terminal (1) determines a maximum number of HARQ processes used for DL transport blocks received in an FDD serving cell (32) based on whether or not the radio terminal (1) is configured to monitor a downlink (DL) control channel of a TDD serving cell (31) for scheduling the FDD serving cell (32). This contributes, for example, to appropriate determination of a maximum number of HARQ processes used for DL transport blocks transmitted in the FDD serving cell when FDD-TDD carrier aggregation (FDD-TDD CA) is configured and when cross-carrier scheduling is configured for DL transmission in the FDD serving cell.
Claims9
A method for performing a downlink hybrid automatic repeat request (HARQ) in a radio terminal which is configured by a base station with a plurality of component carriers including first and second component carriers for carrier aggregation, the method comprising:
- configuring the carrier aggregation using a first serving cell operated using the first component carrier and a second serving cell operated using the second component carrier, the first serving cell using a frame structure type 2 for time division duplex (TDD), the second serving cell using a frame structure type 1 for frequency division duplex (FDD);
- selecting a maximum number of downlink hybrid automatic repeat request (HARQ) processes used for downlink transport blocks received in the second serving cell from a first table defined for TDD when the radio terminal is configured to monitor a first downlink control channel in the first serving cell for scheduling the second serving cell;
- selecting the maximum number from a second table defined for FDD-TDD carrier aggregation when the radio terminal is configured to monitor a second downlink control channel in the second serving cell for scheduling the second serving cell;
- receiving downlink transport blocks in the second serving cell in accordance with the determined maximum number of downlink HARQ processes;
- and
- receiving, by the radio terminal from the base station, a signal indicating whether or not there is a need to selectively use the first and second tables,
- wherein when the signal indicates that there is no need to selectively use the first and second tables, determining the maximum number from the second table, regardless of whether the radio terminal is configured to monitor the first downlink control channel or the second downlink control channel for scheduling the second serving cell.
A radio terminal which is configured by a base station with a plurality of component carriers including first and second component carriers for carrier aggregation, the radio terminal comprising:
- a processor configured to:
- configure the carrier aggregation using a first serving cell operated using the first component carrier and a second serving cell operated using the second component carrier, the first serving cell using a frame structure type 2 for time division duplex (TDD), the second serving cell using a frame structure type 1 for frequency division duplex (FDD);
- select a maximum number of downlink hybrid automatic repeat request (HARD) processes used for downlink transport blocks received in the second serving cell from a first table defined for TDD when the radio terminal is configured to monitor a first downlink control channel in the first serving cell for scheduling the second serving cell;
- select the maximum number from a second table defined for FDD-TDD carrier aggregation when the radio terminal is configured to monitor a second downlink control channel in the second serving cell for scheduling the second serving cell;
- receive downlink transport blocks in the second serving cell in accordance with the determined maximum number of downlink HARQ processes;
- and
- receive, from the base station, a signal indicating whether or not there is a need to selectively use the first and second tables,
- wherein when the signal indicates that there is no need to selectively use the first and second tables, determine the maximum number from the second table, regardless of whether the radio terminal is configured to monitor the first downlink control channel or the second downlink control channel for scheduling the second serving cell.
A method performed by a base station that allocates a plurality of component carriers including first and second component carriers to a radio terminal for carrier aggregation, the method comprising:
- configuring the carrier aggregation using a first serving cell operated using the first component carrier and a second serving cell operated using the second component carrier, the first serving cell using a frame structure type 2 for time division duplex (TDD), the second serving cell using a frame structure type 1 for frequency division duplex (FDD);
- selecting a maximum number of downlink hybrid automatic repeat request (HARQ) processes used for downlink transport blocks received in the second serving cell from a first table defined for TDD when the radio terminal is configured to monitor a first downlink control channel in the first serving cell for scheduling the second serving cell;
- selecting the maximum number from a second table defined for FDD-TDD carrier aggregation when the radio terminal is configured to monitor a second downlink control channel in the second serving cell for scheduling the second serving cell;
- transmitting downlink transport blocks by using multiple HARQ processes in accordance with the maximum number;
- and
- transmitting, to the radio terminal, a signal indicating whether or not there is a need to selectively use the first and second tables,
- wherein the signal causes the radio terminal to, when the signal indicates that there is no need to selectively use the first and second tables, determine the maximum number from the second table, regardless of whether the radio terminal is configured to monitor the first downlink control channel or the second downlink control channel for scheduling the second serving cell.
Dependencies are inferred from the claim text.