Secondary cell group activation by bandwidth part for dual connectivity with multiple radio access technologies

1. A user equipment (UE) for wireless communication, comprising:

one or more memories; and

one or more processors, coupled to the one or more memories, configured to:

operate, in connection with a secondary cell group (SCG) for multiple radio access technology dual connectivity, in an SCG deactivated state in a downlink bandwidth part (BWP) configured for a primary secondary cell of the SCG;

receive a control message associated with activating the SCG for the UE, the control message indicating a BWP switch for the UE;

switch, in connection with receiving the control message, from the downlink BWP to an activated downlink BWP in which the UE operates in an SCG activated state; and

transmit, after entering the SCG activated state from the SCG deactivated state, uplink communications without performing a random access channel procedure.

2. The UE of claim 1 , wherein the control message includes downlink control information received on a primary cell of a master cell group associated with the SCG.

3. The UE of claim 1 , wherein the control message includes a medium access control control element (MAC-CE) received on a primary cell or an activated secondary cell of a master cell group associated with the SCG.

4. The UE of claim 1 , wherein the one or more processors are configured to, after entering the SCG activated state from the SCG deactivated state, perform a random access channel procedure.

5. The UE of claim 1 , wherein the one or more processors are configured to:

receive another control message associated with transitioning to the SCG deactivated state, the another control message indicating another BWP switch; and

switch, in connection with receiving the another control message, to the downlink BWP for operating in the SCG deactivated state.

6. The UE of claim 1 , wherein the one or more processors are configured to:

receive a medium access control control element (MAC-CE) on the primary secondary cell; and

transition to the SCG deactivated state based at least in part on receiving the MAC-CE.

7. The UE of claim 1 , wherein the UE operating in the SCG deactivated state is to refrain from monitoring a physical downlink control channel on the primary secondary cell, refrain from transmitting uplink communications on the primary secondary cell, refrain from performing channel state information (CSI) measurements on the primary secondary cell, refrain from maintaining uplink timing alignment with a secondary node in the primary secondary cell, and perform radio resource management measurements on the primary secondary cell.

8. The UE of claim 1 , wherein the control message is associated with activating the primary secondary cell and one or more other secondary cells of the SCG.

9. A network node for wireless communication, comprising:

one or more memories; and

one or more processors, coupled to the one or more memories, configured to:

determine to instruct a user equipment (UE) to enter into a secondary cell group (SCG) deactivated state or an SCG activated state, in connection with multiple radio access technology dual connectivity;

transmit a control message to the UE indicating for the UE to switch to a deactivated downlink bandwidth part (BWP) configured for a primary secondary cell of the SCG for operating in the SCG deactivated state or an activated downlink BWP configured for the primary secondary cell for operating in the SCG activated state;

determine to instruct the UE to enter the SCG deactivated state; and

transmit a medium access control control element (MAC-CE) on the primary secondary cell, indicating for the UE to transition to the SCG deactivated state, wherein the MAC-CE is to cause the UE to operate in the SCG deactivated state in which the UE is configured to refrain from monitoring a physical downlink control channel on a primary secondary cell of the SCG, refrain from transmitting uplink communications on the primary secondary cell, refrain from performing channel state information (CSI) measurements on the primary secondary cell, refrain from maintaining uplink timing alignment with a secondary node in the primary secondary cell, and perform radio resource management measurements on the primary secondary cell.

10. The network node of claim 9 , wherein the one or more processors, to transmit the control message, are configured to transmit the control message via downlink control information on a primary cell of a master cell group associated with the SCG.

11. The network node of claim 9 , wherein the control message includes a medium access control control element (MAC-CE) on a primary cell or an activated secondary cell of a master cell group associated with the SCG.

12. The network node of claim 9 , wherein the control message is associated with activating the primary secondary cell and one or more other secondary cells of the SCG.

13. A method of wireless communication performed by a user equipment (UE), comprising:

operating, in connection with a secondary cell group (SCG) for multiple radio access technology dual connectivity, in an SCG deactivated state in a downlink bandwidth part (BWP) configured for a primary secondary cell of the SCG;

receiving a control message associated with activating the SCG for the UE, the control message indicating a BWP switch for the UE;

switching, in connection with receiving the control message, from the downlink BWP to an activated downlink BWP in which the UE operates in an SCG activated state; and

transmit, after entering the SCG activated state from the SCG deactivated state, uplink communications without performing a random access channel procedure.

14. The method of claim 13 , further comprising:

receiving another control message associated with transitioning to the SCG deactivated state, the another control message indicating another BWP switch; and

switching, in connection with receiving the another control message, to the deactivated downlink BWP for operating in the SCG deactivated state.

15. The method of claim 13 , further comprising:

receiving a medium access control control element (MAC-CE) on the primary secondary cell; and

transitioning to the SCG deactivated state based at least in part on receiving the MAC-CE.

16. The method of claim 13 , wherein the control message is associated with activating the primary secondary cell and one or more other secondary cells of the SCG.

17. The method of claim 13 , wherein the control message includes downlink control information received on a primary cell of a master cell group associated with the SCG.

18. The method of claim 13 , wherein the control message includes a medium access control control element (MAC-CE) received on a primary cell or an activated secondary cell of a master cell group associated with the SCG.

19. The method of claim 13 , further comprising:

after entering the SCG activated state from the SCG deactivated state, performing a random access channel procedure.

20. The method of claim 13 , further comprising:

after entering the SCG activated state from the SCG deactivated state, transmitting uplink communications without performing a random access channel procedure.

21. The method of claim 13 , wherein transitioning to the SCG deactivated state comprises operating in the SCG deactivated state, in which the UE is configured to refrain from monitoring a physical downlink control channel on a primary secondary cell of the SCG, refrain from transmitting uplink communications on the primary secondary cell, refrain from performing channel state information (CSI) measurements on the primary secondary cell, refrain from maintaining uplink timing alignment with a secondary node in the primary secondary cell, and perform radio resource management measurements on the primary secondary cell.

22. A method of wireless communication performed by a network node, comprising:

determining to instruct a user equipment (UE) to enter into a secondary cell group (SCG) deactivated state or an SCG activated state, in connection with multiple radio access technology dual connectivity;

transmitting a control message to the UE indicating for the UE to switch to a deactivated downlink bandwidth part (BWP) configured for a primary secondary cell of the SCG for operating in the SCG deactivated state or an activated downlink BWP configured for the primary secondary cell for operating in the SCG activated state;

transmitting a medium access control control element (MAC-CE) on the primary secondary cell, indicating for the UE to transition to the SCG deactivated state, wherein the MAC-CE is to cause the UE to operate in the SCG deactivated state in which the UE is configured to refrain from monitoring a physical downlink control channel on a primary secondary cell of the SCG, refrain from transmitting uplink communications on the primary secondary cell, refrain from performing channel state information (CSI) measurements on the primary secondary cell, refrain from maintaining uplink timing alignment with a secondary node in the primary secondary cell, and perform radio resource management measurements on the primary secondary cell.

23. The method of claim 22 , further comprising:

determining to instruct the UE to enter the SCG deactivated state; and

transmitting the MAC-CE on the primary secondary cell, indicating for the UE to transition to the SCG deactivated state.

24. The method of claim 22 , wherein the UE operating in the SCG deactivated state is to refrain from monitoring a physical downlink control channel on the primary secondary cell, refrain from transmitting uplink communications on the primary secondary cell, refrain from performing channel state information (CSI) measurements on the primary secondary cell, refrain from maintaining uplink timing alignment with a secondary node in the primary secondary cell, and perform radio resource management measurements on the primary secondary cell.

25. The method of claim 22 , further comprising:

transmitting the control message via downlink control information on a primary cell of a master cell group associated with the SCG.

26. The method of claim 22 , wherein the control message includes the MAC-CE on a primary cell or an activated secondary cell of a master cell group associated with the SCG.