Suspend-resume in conditional handover
Systems, methods and apparatus are disclosed for handling conditional handover configurations by wireless devices and network nodes. An example method performed by a wireless device includes receiving and storing one or more conditional handover configurations associated with a target cell candidate. The wireless device transitions from a connected state to a sleeping state, where the transition includes discarding the conditional handover configurations. The wireless device releases resources associated with the conditional handover configurations and performs clean up actions relating to conditional handover. An example method performed by a network node includes providing, to a user equipment, one or more conditional handover configurations that are associated with a target cell candidate. The network node transmits, to the user equipment, a message to transition from a connected state to a sleeping state. After transmitting the message, the network node discards the conditional handover configurations.
1. A method performed by a wireless device for handling conditional handover configurations, the method comprising:
while in a connected state:
receiving and storing one or more conditional handover configurations, wherein each of the one or more conditional handover configurations is associated with a target cell candidate;
transitioning from the connected state to a sleeping state, the transitioning including discarding the one or more conditional handover configurations;
releasing resources associated with the one or more conditional handover configurations;
performing one or more clean up actions relating to conditional handover; and
transitioning from the sleeping state to the connected state comprising:
transmitting a Radio Resource Control (RRC) resume request message;
receiving an RRC resume message including at least one conditional handover configuration; and
performing one or more actions responsive to the at least one conditional handover configuration.
2. The method of claim 1 , wherein the connected state comprises RRC_CONNECTED.
3. The method of claim 1 , wherein the sleeping state comprises RRC_INACTIVE or RRC_IDLE.
4. The method of claim 1 , wherein the releasing of the resources is performed upon reception of an Radio Resource Control (RRC) release message.
5. The method of claim 1 , wherein the one or more clean up actions comprise one or more of:
discarding state variables;
discarding measurements that were monitored for conditional handover conditions;
stopping monitoring corresponding to conditional handover conditions; or
stopping timers associated with conditional handover procedures.
6. A user equipment (UE) comprising:
a non-transitory memory; and
processing circuitry coupled to the non-transitory memory and configured to read instructions from the non-transitory memory to cause the user equipment to perform operations comprising:
while in a connected state:
receiving and storing one or more conditional handover configurations, wherein each of the one or more conditional handover configurations is associated with a target cell candidate;
transitioning from the connected state to a sleeping state, the transitioning including discarding the one or more conditional handover configurations;
releasing resources associated with the one or more conditional handover configurations;
performing one or more clean up actions relating to conditional handover; and
transitioning from the sleeping state to the connected state comprising:
transmitting a Radio Resource Control (RRC) resume request message;
receiving an RRC resume message including at least one conditional handover configuration; and
performing one or more actions responsive to the received at least one conditional handover configuration.
7. The user equipment of claim 6 , wherein the connected state comprises RRC_CONNECTED.
8. The user equipment of claim 6 , wherein the sleeping state comprises RRC_INACTIVE or RRC_IDLE.
9. The user equipment of claim 6 , wherein the releasing of the resources is performed upon reception of an Radio Resource Control (RRC) release message.
10. The user equipment of claim 6 , wherein the one or more clean up actions comprise one or more of:
discarding state variables;
discarding measurements that were monitored for conditional handover conditions;
stopping monitoring corresponding to conditional handover conditions; or
stopping timers associated with conditional handover procedures.
11. A non-transitory computer-readable storage medium having stored thereon instructions executable to cause a wireless device to perform operations comprising:
while in a connected state:
receiving and storing one or more conditional handover configurations, wherein each of the one or more conditional handover configurations is associated with a target cell candidate;
transitioning from the connected state to a sleeping state, the transitioning including discarding the one or more conditional handover configurations;
releasing resources associated with the one or more conditional handover configurations;
performing one or more clean up actions relating to conditional handover; and
transitioning from the sleeping state to the connected state comprising:
transmitting a Radio Resource Control (RRC) resume request message;
receiving an RRC resume message including at least one conditional handover configuration; and
performing one or more actions responsive to the at least one conditional handover configuration.
12. The non-transitory computer-readable storage medium of claim 11 , wherein the connected state comprises RRC_CONNECTED.
13. The non-transitory computer-readable storage medium of claim 11 , wherein the sleeping state comprises RRC_INACTIVE or RRC_IDLE.
14. The non-transitory computer-readable storage medium of claim 11 , wherein the releasing of the resources is performed upon reception of an Radio Resource Control (RRC) release message.
15. The non-transitory computer-readable storage medium of claim 11 , wherein the one or more clean up actions comprise one or more of:
discarding state variables;
discarding measurements that were monitored for conditional handover conditions;
stopping monitoring corresponding to conditional handover conditions; or
stopping timers associated with conditional handover procedures.