Traffic-rate based branch deactivation for UE power efficiency in a dual-connectivity mode
A user equipment (UE) device may reside in a state of dual connectivity with a master cell group (MCG) and a secondary cell group (SCG), wherein the radio access technologies of the MCG and the SCG are different. While in the dual connectivity state, the UE device may transition to a mode of reduced activity (e.g., processing and/or RF activity) relative to the secondary cell group (SCG) in order to save power, e.g., when traffic flow via the SCG is below a threshold, or when scheduling activity on the SCG is low. Various mechanisms may be employed to reduce activity, e.g., mechanisms such as reduction of beam monitoring, deactivation of secondary cells of the SCG, reduction of number of active antenna elements, employment of longer periods for periodic measurement and reporting processes, etc.
1. A wireless user equipment (UE) device comprising:
radio circuitry configured to transmit and receive radio signals; and
a processor communicatively coupled to the radio circuitry and configured to cooperate with the radio circuitry to:
transmit, to a master node when the UE device is in a state of dual connectivity to one or more cells of a master cell group (MCG) of the master node and one or more cells of a secondary cell group (SCG) of a secondary node, an indication of a preference to have the SCG deactivated;
receive, from the master node subsequent to transmission of the indication, a deactivation indication of the SCG having been deactivated; and
perform communications with the master node subsequent to reception of the deactivation indication.
2. The UE device of claim 1 , wherein the processor is configured to further cooperate with the radio circuitry to transmit, to the master node subsequent to performing the communications, an SCG activation request to have the SCG activated.
3. The UE device of claim 1 , wherein the processor is configured to cooperate with the radio circuitry to perform any one or more of the following upon entering the state of dual connectivity:
report cell measurement relative to a primary cell of the secondary cell group, with longer cycle than prior to entering the state of dual connectivity;
track one or more beams relative to the primary cell of the secondary cell group, with longer cycle than prior to entering the state of dual connectivity;
report information regarding channel quality relative to the primary cell of the secondary cell group, with longer cycle than prior to entering the state of dual connectivity;
transmit sounding reference signals (SRSs) to the primary cell of the secondary cell group, with longer cycle than prior to entering the state of dual connectivity;
terminate monitoring of a Physical Downlink Shared Channel (PDSCH) of the primary cell of the secondary cell group;
terminate monitoring of a Physical Downlink Control Channel (PDCCH) of the primary cell of the secondary cell group;
disable transmission on a Physical Uplink Shared Channel (PUSCH) associated with the secondary cell group; or
terminate measurements related to radio link monitoring (RLM) with respect to the secondary cell group.
4. The UE device of claim 1 , wherein the state of dual connectivity is entered in response to a command from the master node or the secondary node, wherein the command is received in a Radio Resource Control (RRC) message or in a Medium Access Control (MAC) Control Element or as part of downlink control information (DCI).
5. The UE device of claim 1 , wherein the processor is further configured to:
start an inactivity timer in response to receiving uplink and/or downlink scheduling with respect to the secondary node; and
restart the inactivity timer in response to receiving additional uplink and/or downlink scheduling with respect to the secondary node while the inactivity timer is running;
wherein the state of dual connectivity is entered in response to expiration of the inactivity timer.
6. The UE device of claim 1 , wherein the processor is further configured to:
start a timer in response to determining that a first traffic rate relating to data communication with the secondary node is lower than a specified rate; and
stop the timer in response to determining that a subsequent traffic rate relating to the data communication with the secondary node is greater than the specified rate;
wherein the state of dual connectivity is entered in response to expiration of the timer.
7. The UE device of claim 1 , wherein the master node corresponds to a first radio access technology and wherein the secondary node corresponds to a second radio access technology different from the first radio access technology.
8. A network master node comprising:
radio circuitry configured to transmit and receive radio signals; and
a processor communicatively coupled to the radio circuitry and configured to cooperate with the radio circuitry to:
receive, from a wireless user equipment (UE) device when the UE device is in a state of dual connectivity to one or more cells of a master cell group (MCG) of the master node and one or more cells of a secondary cell group (SCG) of a secondary node, a first indication of a preference to have the SCG deactivated;
transmit, to the UE device subsequent to reception of the first indication, a deactivation indication of the SCG having been deactivated; and
perform communications with the UE device subsequent to transmission of the deactivation indication.
9. The network master node of claim 8 , wherein the processor is configured to further cooperate with the radio circuitry to receive, from the UE device subsequent to performing the communications, an SCG activation request to have the SCG activated.
10. The network master node of claim 8 , wherein the processor is configured to further cooperate with the radio circuitry to transmit, to the UE device to have the UE device enter the state of dual connectivity, a command via one or more of:
a Radio Resource Control (RRC) message;
a Medium Access Control (MAC) Control Element; or
downlink control information (DCI).
11. The network master node of claim 8 , wherein the processor is configured to further cooperate with the radio circuitry to:
receive, from the UE device, a threshold indication of a traffic threshold, wherein the traffic threshold represents a boundary between
traffic rates sufficiently small so that reduction in activity relative to the secondary node is recommended, and
traffic rates sufficiently large so that reduction in activity relative to the secondary node is not recommended; and
transmit, based at least on the threshold indication, a message to the UE device to direct the UE device to enter a mode of reduced activity relative to the secondary node.
12. The network master node of claim 11 , wherein the traffic threshold is determined based on at least one of:
mobility of the UE device;
condition of RF channel relative to the secondary node;
a configuration of the UE device with respect to a radio access technology (RAT) corresponding to the master node; or
a configuration of the UE device with respect to a RAT corresponding to the secondary node.
13. The network master node of claim 8 , wherein the master node is a base station conforming to specifications of a first radio access technology (RAT), and wherein the secondary node is a base station conforming to specifications of a second RAT different from the first RAT.
14. A non-transitory memory medium storing programming instructions, which, when executed by a processor, instruct a user equipment (UE) device to:
transmit, to a master node when the UE device is in a state of dual connectivity to one or more cells of a master cell group (MCG) of the master node and one or more cells of a secondary cell group (SCG) of a secondary node, an indication of a preference to have the SCG deactivated;
receive, from the master node subsequent to transmission of the indication, a deactivation indication of the SCG having been deactivated; and
perform communications with the master node subsequent to reception of the deactivation indication.
15. The non-transitory memory medium of claim 14 , wherein the instructions, when executed by the processor, further instruct the UE device to:
transmit, to the master node subsequent to performing the communications, an SCG activation request to have the SCG activated.
16. The non-transitory memory medium of claim 14 , wherein the instructions, when executed by the processor, further instruct the UE device to:
report cell measurement relative to a primary cell of the secondary cell group, with longer cycle than prior to entering the state of dual connectivity;
track one or more beams relative to the primary cell of the secondary cell group, with longer cycle than prior to entering the state of dual connectivity;
report information regarding channel quality relative to the primary cell of the secondary cell group, with longer cycle than prior to entering the state of dual connectivity;
transmit sounding reference signals (SRSs) to the primary cell of the secondary cell group, with longer cycle than prior to entering the state of dual connectivity;
terminate monitoring of a Physical Downlink Shared Channel (PDSCH) of the primary cell of the secondary cell group;
terminate monitoring of a Physical Downlink Control Channel (PDCCH) of the primary cell of the secondary cell group;
disable transmission on a Physical Uplink Shared Channel (PUSCH) associated with the secondary cell group; or
terminate measurements related to radio link monitoring (RLM) with respect to the secondary cell group.
17. The non-transitory memory medium of claim 14 , wherein the state of dual connectivity is entered in response to a command from the master node or the secondary node, wherein the command is received in a Radio Resource Control (RRC) message or in a Medium Access Control (MAC) Control Element or as part of downlink control information (DCI).
18. The non-transitory memory medium of claim 14 , wherein the instructions, when executed by the processor, further instruct the UE device to:
start an inactivity timer in response to receiving uplink and/or downlink scheduling with respect to the secondary node; and
restart the inactivity timer in response to receiving additional uplink and/or downlink scheduling with respect to the secondary node while the inactivity timer is running;
wherein the state of dual connectivity is entered in response to expiration of the inactivity timer.
19. The non-transitory memory medium of claim 14 , wherein the instructions, when executed by the processor, further instruct the UE device to:
start a timer in response to determining that a first traffic rate relating to data communication with the secondary node is lower than a specified rate; and
stop the timer in response to determining that a subsequent traffic rate relating to the data communication with the secondary node is greater than the specified rate;
wherein the state of dual connectivity is entered in response to expiration of the timer.
20. The non-transitory memory medium of claim 14 , wherein the master node corresponds to a first radio access technology and wherein the secondary node corresponds to a second radio access technology different from the first radio access technology.