Method and apparatus to improve inter-band carrier aggregation (CA) in TDD (time division duplex) mode

Abstract

A method and apparatus are disclosed to improve inter-band carrier aggregation (CA) in a UE (User Equipment) in TDD (Time Division Duplex) mode. In one embodiment, the method includes connecting the UE with a PCell (Primary Serving Cell). The method further includes configuring the UE with at least one SCell (Secondary Serving Cell), among which at least one SCell is deactivated, wherein TDD UL-DL (Uplink-Downlink) configurations of the PCell and the at least one SCell may be different. The method also includes taking a TDD UL-DL configuration of an activated serving cell into consideration for defining consecutive PDCCH (Physical Downlink Control Channel) subframes of a drx-InactivityTimer, and not taking a TDD UL-DL configuration of a deactivated serving cell into consideration.

What is claimed is: 
     
       1. A method for inter-band carrier aggregation in a UE (User Equipment) in TDD (Time Division Duplex) mode, comprising:
 connecting the UE with a PCell (Primary Serving Cell), wherein the PCell is always activated; 
 configuring the UE with at least one SCell (Secondary Serving Cell), among which at least one SCell is deactivated, wherein TDD UL-DL (Uplink-Downlink) configurations of the PCell and the at least one SCell are different; and 
 taking a TDD UL-DL configuration of an activated serving cell into consideration for defining consecutive PDCCH (Physical Downlink Control Channel) subframes of a drx-InactivityTimer, and not taking a TDD UL-DL configuration of a deactivated serving cell into consideration, 
 wherein there is only one DRX (Discontinuous Reception) configuration applied for the PCell and the at least one SCell, 
 wherein the activated serving cell refers to the PCell or the SCell that is activated, and the deactivated serving cell refers to the SCell that is deactivated, and 
 wherein an Activation/Deactivation MAC (Medium Access Control) control element (CE) is used to activate/deactivate the at least one SCell. 
 
     
     
       2. The method of  claim 1 , wherein PDCCH subframes for defining the drx-InactivityTimer are equal to a union of PDCCH subframes of all activated serving cells. 
     
     
       3. The method of  claim 1 , wherein the activated serving cell taken into consideration for defining consecutive PDCCH subframes of the drx-InactivityTimer is configured with a PDCCH. 
     
     
       4. The method of  claim 1 , further comprising:
 defining consecutive PDCCH subframes of an onDurationTimer based on a TDD UL-DL configuration of the PCell. 
 
     
     
       5. The method of  claim 1 , further comprising:
 defining consecutive PDCCH subframes of a drx-RetransmissionTimer based on a TDD UL-DL configuration of a serving cell which owns a HARQ process associated with the drx-Retransmission Timer, wherein the serving cell refers to the PCell or an SCell of the at least one SCell. 
 
     
     
       6. The method of  claim 1 , further comprising:
 defining consecutive PDCCH subframes of a drx-RetransmissionTimer based on a TDD UL-DL configuration of a scheduling cell of a serving cell which owns a HARQ process associated with the drx-RetransmissionTimer, wherein the serving cell refers to the PCell or a SCell of the at least one SCell. 
 
     
     
       7. The method of  claim 5 , wherein the drx-RetransmissionTimer is stopped when the corresponding SCell is deactivated. 
     
     
       8. The method of  claim 6 , wherein the drx-RetransmissionTimer is stopped when the corresponding scheduling cell is deactivated. 
     
     
       9. A communication device for inter-band carrier aggregation in a UE (User Equipment) in TDD (Time Division Duplex) mode, the communication device comprising:
 a control circuit; 
 a processor installed in the control circuit; 
 a memory installed in the control circuit and coupled to the processor; 
 wherein the processor is configured to execute a program code stored in memory for inter-band carrier aggregation by:
 connecting the UE with a PCell (Primary Serving Cell), wherein the PCell is always activated; 
 configuring the UE with at least one SCell (Secondary Serving Cell), among which at least one SCell is deactivated, wherein TDD UL-DL (Uplink-Downlink) configurations of the PCell and the at least one SCell are different; and 
 taking a TDD UL-DL configuration of an activated serving cell into consideration for defining consecutive PDCCH (Physical Downlink Control Channel) subframes of a drx-InactivityTimer, and not taking a TDD UL-DL configuration of a deactivated serving cell into consideration, 
 wherein there is only one DRX (Discontinuous Reception) configuration applied for the PCell and the at least one SCell, 
 wherein the activated serving cell refers to the PCell or the SCell that is activated, and the deactivated serving cell refers to the SCell that is deactivated, and 
 wherein an Activation/Deactivation MAC (Medium Access Control) control element (CE) is used to activate/deactivate the at least one SCell. 
 
 
     
     
       10. The communication device of  claim 9 , wherein PDCCH subframes for defining the drx-InactivityTimer are equal to a union of PDCCH subframes of all activated serving cells. 
     
     
       11. The communication device of  claim 9 , wherein the activated SCell taken into consideration for defining consecutive PDCCH subframes of the drx-InactivityTimer is configured with a PDCCH. 
     
     
       12. The communication device of  claim 9 , further comprising:
 defining consecutive PDCCH subframes of an onDurationTimer based on a TDD UL-DL configuration of the PCell. 
 
     
     
       13. The communication device of  claim 9 , further comprising:
 defining consecutive PDCCH subframes of a drx-RetransmissionTimer based on a TDD UL-DL configuration of a serving cell which owns a HARQ process associated with the drx-RetransmissionTimer, wherein the serving cell refers to the PCell or an SCell of the at least one SCell. 
 
     
     
       14. The communication device of  claim 9 , further comprising:
 defining consecutive PDCCH subframes of a drx-RetransmissionTimer based on a TDD UL-DL configuration of a scheduling cell of a serving cell which owns a HARQ process associated with the drx-RetransmissionTimer, wherein the serving cell refers to the PCell or a SCell of the at least one SCell. 
 
     
     
       15. The communication device of  claim 13 , wherein the drx-RetransmissionTimer is stopped when the corresponding SCell is deactivated. 
     
     
       16. The communication device of  claim 14 , wherein the drx-RetransmissionTimer is stopped when the corresponding scheduling cell is deactivated.