Conditions for transitioning to or remaining in inactive state
A wireless communication device, WCD, receives a message from a network node in a communication network. The message indicates that the WCD is to save a user equipment, UE, context of the WCD. In response to receiving the message, the WCD saves the UE context. The message also indicates that the WCD is to transition from a connected state to an inactive state when a first condition is satisfied, and/or remain in an inactive state when a second condition is satisfied. The first and/or second condition may for example include that the WCD experiences a loss of connection or loss of coverage, or that the WCD experiences a radio link failure.
1 . A method at a wireless communication device, WCD, the method comprising:
receiving a conditional message from a network node in a communication network, the conditional message comprising:
a radio resource control, RRC, release message;
an information element, IE; and
a condition in the IE of the conditional message regarding when to use the IE; and
responsive to receiving the conditional message, saving a user equipment, UE, context of the WCD; and
applying the received conditional message to trigger the WCD to one or both:
wait to transition from a connected state to an inactive state until a first condition in the IE is satisfied; and
remain, without transition, in an inactive state after a second condition in the IE is satisfied.
2 . The method of claim 1 , wherein the UE context of the WCD is a UE Inactive Access Stratum, AS, context.
3 . The method of claim 1 , further comprising:
after receiving the conditional message and while the WCD is in the inactive state, detecting a synchronization signal from a cell in the communication network; and
after detecting the synchronization signal, using the saved UE context of the WCD to transmit data to the communication network.
4 . The method of claim 3 , wherein the data is transmitted while the WCD is in the inactive state.
5 . The method of claim 3 , wherein the data is transmitted in a message 3 of a four-step random access procedure, or in a message A of a two-step random access procedure.
6 . The method of claim 3 , wherein the conditional message is transmitted via a first cell served by the network node, wherein the data is transmitted in uplink resources which were configured via the first cell while the WCD was in the connected state.
7 . The method of claim 6 , wherein one or both:
the synchronization signal is received via the first cell; and
the data is transmitted via the first cell.
8 . The method of claim 1 , further-comprising:
responsive to receiving the conditional message and while the WCD is in the inactive state:
detecting a synchronization signal from a cell in the communication network; and
after detecting the synchronization signal, using the saved UE context of the WCD to connect to the cell.
9 . The method of claim 1 , wherein one or both of the first and second condition involve use of a timer, and wherein a duration of the timer is:
indicated in the IE; or
indicated in another conditional message transmitted to the WCD; or
predefined at the WCD.
10 . A wireless communication device (WCD), comprising:
processing circuitry configured to cause the WCD to:
receive a conditional message from a network node in a communication network, the conditional message comprising:
a radio resource control, RRC, release message;
an information element, IE; and
a condition in the IE of the conditional message regarding when to use the IE;
responsive to receiving the conditional message, save a user equipment, UE, context of the WCD; and
apply the received conditional message to trigger the WCD to one or both:
wait to transition from a connected state to an inactive state until a first condition in the IE is satisfied; and
remain, without transition, in an inactive state after a second condition in the IE is satisfied.
11 . A method at a network node in a communication network, the method comprising:
transmitting a conditional message to a wireless communication device (WCD), the conditional message indicating that the WCD is to save a user equipment (UE) context of the WCD, the conditional message comprising:
a radio resource control, RRC, release message;
an information element, IE; and
a condition in the IE of the conditional message regarding when to use the IE; and
applying the conditional message to trigger the WCD to one or both:
wait to transition from a connected state to an inactive state until a first condition in the IE is satisfied; and
remain, without transition, in an inactive state after a second condition in the IE is satisfied.
12 . The method of claim 11 , further comprising:
after transmitting the conditional message and while the WCD is in the inactive state, transmitting a synchronization signal via a cell in the communication network; and
after transmitting the synchronization signal, using the saved UE context of the WCD to receive data from the WCD.
13 . The method of claim 12 , wherein the data is received in a message 3 of a four-step random access procedure, or in a message A of a two-step random access procedure.
14 . The method of claim 12 , wherein the conditional message is transmitted via a first cell served by the network node, and wherein the data is received in uplink resources which were configured via the first cell while the WCD was in the connected state.
15 . The method of claim 11 , wherein the conditional message indicates that the WCD is to:
remain in the inactive state instead of transitioning to the idle state if the second condition is satisfied.
16 . The method of claim 11 , wherein the conditional message indicates one or more parameters for one or both of encryption and context fetching, to be used by the WCD for a future resumption of connection.
17 . A network node for operation in a communication network, the network node comprising processing circuitry configured to cause the network node to:
transmit a conditional message to a wireless communication device (WCD), the conditional message indicating that the WCD is to save a user equipment (UE) context of the WCD, the conditional message comprising:
a radio resource control, RRC, release message;
an information element, IE; and
a condition in the IE of the conditional message regarding when to use the IE; and
apply the conditional message to trigger the WCD to one or both:
wait to transition from a connected state to an inactive state until a first condition in the IE is satisfied; and
remain, without transition, in an inactive state after a second condition in the IE is satisfied.